WorldWideScience

Sample records for rankin scale score

  1. Optimizing cutoff scores for the Barthel Index and the modified Rankin Scale for defining outcome in acute stroke trials

    NARCIS (Netherlands)

    Uyttenboogaart, Maarten; Stewart, Roy E; Vroomen, Patrick C A J; De Keyser, Jacques; Luijckx, Gert-Jan

    Background and Purpose - There is little agreement on how to assess outcome in acute stroke trials. Cutoff scores for the Barthel Index (BI) and modified Rankin Scale (mRS) are frequently arbitrarily chosen to dichotomize favorable and unfavorable outcome. We investigated sensitivity and specificity

  2. Relationship between Barthel Index (BI and the Modified Rankin Scale (mRS Score in Assessing Functional Outcome in Acute Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    C S Mohanty

    2016-01-01

    Conclusion: Our study has demonstrated that stroke functional outcome can be predicted from the baseline BI and mRS scales. It is concluded thatBI and mRS Stroke scale can be used to prognosticate functional outcome at admission and at follow up.

  3. Mobile Phone-Based Questionnaire for Assessing 3 Months Modified Rankin Score After Acute Stroke: A Pilot Study.

    Science.gov (United States)

    Cooray, Charith; Matusevicius, Marius; Wahlgren, Nils; Ahmed, Niaz

    2015-10-01

    In many countries, a majority of stroke patients are not assessed for long-term functional outcome owing to limited resources and time. We investigated whether automatic assessment of the modified Rankin Scale (mRS) based on a mobile phone questionnaire may serve as an alternative to mRS assessments at clinical visits after stroke. We enrolled 62 acute stroke patients admitted to our stroke unit during March to May 2014. Forty-eight patients completed the study. During the stay, patients and/or caregivers were equipped with a mobile phone application in their personal mobile phones. The mobile phone application contained a set of 20 questions, based on the Rankin Focused Assessment, which we previously tested in a pilot study. Three months after inclusion, the mobile phone application automatically prompted the study participants to answer the mRS questionnaire in the mobile phones. Each question or a group of questions in the questionnaire corresponded to a certain mRS score. Using a predefined protocol, the highest mRS score question where the study participant had answered yes was deemed the final mobile mRS score. A few days later, a study personnel performed a clinical visit mRS assessment. The 2 assessments were compared using quadratic weighing κ-statistics. Mean age was 67 years (38% females), and median baseline National Institutes of Health Stroke Scale (NIHSS) score was 5 (interquartile range 2-10.5, range 0-23). Median and mean clinical visit mRS at 3 months was 2 and 2.3, respectively. We found a 62.5% agreement between clinical visit and mobile mRS assessment, weighted kappa 0.89 (95% confidence interval 0.82-0.96), and unweighted kappa 0.53 (95% confidence interval 0.36-0.70). Dichotomized mRS outcome separating functionally independent (mRS score 0-2) from dependent (mRS score 3-5) showed 83% agreement and unweighted kappa of 0.66 (95% confidence interval 0.45-0.87). Mobile phone-based automatic assessments of mRS performed well in comparison with

  4. Working fluid charge oriented off-design modeling of a small scale Organic Rankine Cycle system

    International Nuclear Information System (INIS)

    Liu, Liuchen; Zhu, Tong; Ma, Jiacheng

    2017-01-01

    Highlights: • Organic Rankine Cycle model considering working fluid charge has been established. • Overall solution algorithm of system off-design performance is proposed. • Variation trend of different zones in both heat exchangers can be observed. • Optimal working fluid charge volume for different output work has been estimated. - Abstract: Organic Rankine Cycle system is one of the most widely used technique for low-grade waste heat recovery. Developing of dynamic Organic Rankine Cycle models played an increasingly important part in system performance prediction. The present paper developed a working fluid charge oriented model for an small scale Organic Rankine Cycle to calculate the theoretical value of working fluid charge level for the system under rated condition. The two heat exchangers are divided into three different zones and related heat transfer correlations are employed to estimate the length variation of each zones. Steady state models have been applied to describe the performance of pump and expander. Afterwards, an overall solution algorithm based on the established model has been proposed in order to exact simulate the system’s off-design performance. Additionally, the impact of different working fluid charge volumes has also been discussed. Simulation results clearly shows the variation trend of different zones in both heat exchangers, as well as the variation trend of system operating parameters under various expander output work. Furthermore, the highest thermal efficiency can be reached 6.37% under rated conditions with a working fluid charge volume of 34.6 kg.

  5. Parametric analysis of blade configurations for a small-scale nitrogen axial expander with hybrid open-Rankine cycle

    International Nuclear Information System (INIS)

    Khalil, Khalil M.; Mahmoud, S.; Al- Dadah, R.K.; AL-Mousawi, Fadhel

    2017-01-01

    Highlights: • Develop cryogenic energy storage and efficient recovery technologies. • Integrate small scale closed and cryogenic open-Rankine cycles. • Investigate blade configuration on small-scale axial expander performance. • Use mean line and 3D CFD simulation for expander robust design procedure. • Predict effects of expander efficiency on hybrid open-Rankine cycle efficiency. - Abstract: During the last few decades, low-grade energy sources such as solar energy and wind energy have enhanced the efficiency of the advanced renewable technologies such as the combined Rankine. Furthermore, these heat sources have contributed to a reduction in CO2 emissions. To address the problem of the intermittent nature of such renewable sources, energy storage technologies have been used to balance the power demand and smooth out energy production. In this study, the direct expansion cycle (open Rankine cycle) is combined with a closed loop Rankine cycle to generate power more efficiently and address the problem of discontinuous renewable sources. The topping cycle of this system is a closed looped Rankine cycle and propane is used as a hydrocarbon fluid, while the direct expansion cycle is considered to be the bottoming cycle utilizing nitrogen as cryogen fluid. Small-scale expanders are the most important parts in many thermal power cycles, such as the Rankine cycle, due to the significant impact on the overall cycle’s efficiency. This work investigated the effect of using a number of blade configurations on the cycle’s performance using a small-scale axial expander. A three-dimensional Computational Fluid Dynamic (CFD) simulation was used to examine four proposed blade configurations (lean, sweep, twist, bowl) with three hub- tip ratios (0.83, 0.75, 0.66). In addition, a numerical simulation model of the hybrid open expansion- Rankine cycle was designed and modeled in order to estimate the cycle’s performance. The results show that when the expander

  6. Evaluation of external heat loss from a small-scale expander used in organic Rankine cycle

    International Nuclear Information System (INIS)

    Li Jing; Pei Gang; Li Yunzhu; Ji Jie

    2011-01-01

    With the scaling down of the Organic Rankine Cycle (ORC), the engine shaft power is not only determined by the enthalpy drop in the expansion process but also the external heat loss from the expander. Theoretical and experimental support in evaluating small-scale expander heat loss is rare. This paper presents a quantitative study on the convection, radiation, and conduction heat transfer from a kW-scale expander. A mathematical model is built and validated. The results show that the external radiative or convective heat loss coefficient was about 3.2 or 7.0 W/K.m 2 when the ORC operated around 100 o C. Radiative and convective heat loss coefficients increased as the expander operation temperature increased. Conductive heat loss due to the connection between the expander and the support accounted for a large proportion of the total heat loss. The fitting relationships between heat loss and mean temperature difference were established. It is suggested that low conductivity material be embodied in the support of expander. Mattress insulation for compact expander could be eliminated when the operation temperature is around 100 o C. - Highlights: → A close examination of external heat loss from a small expander is presented. → Theoretical analysis and experimental test were conducted. → The established formulas can be applied to other small ORC expanders. → The results are useful in further research of small-scale ORC.

  7. Validation of a structured interview for telephone assessment of the modified Rankin Scale in Brazilian stroke patients.

    Science.gov (United States)

    Baggio, Jussara A O; Santos-Pontelli, Taiza E G; Cougo-Pinto, Pedro T; Camilo, Millene; Silva, Nathalia F; Antunes, Paula; Machado, Laura; Leite, João P; Pontes-Neto, Octavio M

    2014-01-01

    The modified Rankin Scale (mRS) is a commonly used scale to assess the functional outcome after stroke. Several studies on mRS showed good reliability, feasibility, and interrater agreement of this scale using a face-to-face assessment. However, telephone assessment is a more time-efficient way to obtain an mRS grade than a face-to-face interview. The aim of this study was to validate the telephone assessment of mRS among the Portuguese using a structured interview in a sample of Brazilian stroke patients. We evaluated 50 stroke outpatients twice. The first interview was face-to-face and the second was made by telephone and the time between the two assessments ranged between 7 and 14 days. Four certified raters evaluated the patients using a structured interview based on a questionnaire previously published in the literature. Raters were blinded for the Rankin score given by the other rater. For both assessments, the rater could also interview a caregiver if necessary. The patients' mean age was 62.8 ± 14.7, mean number of years of study 5.2 ± 3.4, 52% were males, 55.2% of patients needed a caregiver's help to answer the questions. The majority of caregivers were female (85%), mean age 49.1 ± 15, and mean number of years of study 8.3 ± 3.4. Perfect agreement between the telephone and face-to-face assessments was obtained for 27 (54%) patients, corresponding to an unweighted Kappa of 0.44 (95% CI 0.27-0.61) and a weighted Kappa of 0.89. The median of telephone assessment mRS was 3.5 (interquartile range = 2-4) and of face-to-face assessment was 4 (interquartile range = 2-5). There was no difference between the two assessments (Wilcoxon test, p = 0.35). Despite the low education level of our sample, the telephone assessment of functional impairment of stroke patients using a translated and culturally adapted Brazilian Portuguese version of the mRS showed good validity and reliability. Therefore, the telephone assessment of mRS can be used in clinical practice and

  8. Performance estimation of Tesla turbine applied in small scale Organic Rankine Cycle (ORC) system

    International Nuclear Information System (INIS)

    Song, Jian; Gu, Chun-wei; Li, Xue-song

    2017-01-01

    Highlights: • One-dimensional model of the Tesla turbine is improved and applied in ORC system. • Working fluid properties and system operating conditions impact efficiency. • The influence of turbine efficiency on ORC system performance is evaluated. • Potential of using Tesla turbine in ORC systems is estimated. - Abstract: Organic Rankine Cycle (ORC) system has been proven to be an effective method for the low grade energy utilization. In small scale applications, the Tesla turbine offers an attractive option for the organic expander if an efficient design can be achieved. The Tesla turbine is simple in structure and is easy to be manufactured. This paper improves the one-dimensional model for the Tesla turbine, which adopts a non-dimensional formulation that identifies the dimensionless parameters that dictates the performance features of the turbine. The model is used to predict the efficiency of a Tesla turbine that is applied in a small scale ORC system. The influence of the working fluid properties and the operating conditions on the turbine performance is evaluated. Thermodynamic analysis of the ORC system with different organic working fluids and under various operating conditions is conducted. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, the Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.

  9. Exergy analysis of micro-organic Rankine power cycles for a small scale solar driven reverse osmosis desalination system

    International Nuclear Information System (INIS)

    Tchanche, B.F.; Lambrinos, Gr.; Frangoudakis, A.; Papadakis, G.

    2010-01-01

    Exergy analysis of micro-organic Rankine heat engines is performed to identify the most suitable engine for driving a small scale reverse osmosis desalination system. Three modified engines derived from simple Rankine engine using regeneration (incorporation of regenerator or feedliquid heaters) are analyzed through a novel approach, called exergy-topological method based on the combination of exergy flow graphs, exergy loss graphs, and thermoeconomic graphs. For the investigations, three working fluids are considered: R134a, R245fa and R600. The incorporated devices produce different results with different fluids. Exergy destruction throughout the systems operating with R134a was quantified and illustrated using exergy diagrams. The sites with greater exergy destruction include turbine, evaporator and feedliquid heaters. The most critical components include evaporator, turbine and mixing units. A regenerative heat exchanger has positive effects only when the engine operates with dry fluids; feedliquid heaters improve the degree of thermodynamic perfection of the system but lead to loss in exergetic efficiency. Although, different modifications produce better energy conversion and less exergy destroyed, the improvements are not significant enough and subsequent modifications of the simple Rankine engine cannot be considered as economically profitable for heat source temperature below 100 °C. As illustration, a regenerator increases the system's energy efficiency by 7%, the degree of thermodynamic perfection by 3.5% while the exergetic efficiency is unchanged in comparison with the simple Rankine cycle, with R600 as working fluid. The impacts of heat source temperature and pinch point temperature difference on engine's performance are also examined. Finally, results demonstrate that energy analysis combined with the mathematical graph theory is a powerful tool in performance assessments of Rankine based power systems and permits meaningful comparison of different

  10. Experimental and Thermoeconomic Analysis of Small-Scale Solar Organic Rankine Cycle (SORC System

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-04-01

    Full Text Available A small-scale solar organic Rankine cycle (ORC is a promising renewable energy-driven power generation technology that can be used in the rural areas of developing countries. A prototype was developed and tested for its performance characteristics under a range of solar source temperatures. The solar ORC system power output was calculated based on the thermal and solar collector efficiency. The maximum solar power output was observed in April. The solar ORC unit power output ranged from 0.4 kW to 1.38 kW during the year. The highest power output was obtained when the expander inlet pressure was 13 bar and the solar source temperature was 120 °C. The area of the collector for the investigation was calculated based on the meteorological conditions of Busan City (South Korea. In the second part, economic and thermoeconomic analyses were carried out to determine the cost of energy per kWh from the solar ORC. The selling price of electricity generation was found to be $0.68/kWh and $0.39/kWh for the prototype and low cost solar ORC, respectively. The sensitivity analysis was carried out in order to find the influencing economic parameters for the change in NPV. Finally, the sustainability index was calculated to assess the sustainable development of the solar ORC system.

  11. Three dimensional optimization of small-scale axial turbine for low temperature heat source driven organic Rankine cycle

    International Nuclear Information System (INIS)

    Al Jubori, Ayad; Al-Dadah, Raya K.; Mahmoud, Saad; Bahr Ennil, A.S.; Rahbar, Kiyarash

    2017-01-01

    Highlights: • Three-dimensional optimization of axial turbine stage is presented. • Six organic fluids suitable for low-temperature heat source are considered. • Three-dimensional optimization has been done for each working fluid. • The results showed highlight the potential of optimization technique. • The performance of optimized turbine has been improved off-design conditions. - Abstract: Advances in optimization techniques can be used to enhance the performance of turbines in various applications. However, limited work has been reported on using such optimization techniques to develop small-scale turbines for organic Rankine cycles. This paper investigates the use of multi-objective genetic algorithm to optimize the stage geometry of a small-axial subsonic turbine. This optimization is integrated with organic Rankine cycle analysis using wide range of high density organic working fluids like R123, R134a, R141b, R152a, R245fa and isobutane suitable for low temperature heat sources <100 °C such as solar energy to achieve the best turbine design and highest organic Rankine cycle efficiency. The isentropic efficiency of the turbine in most of the reported organic Rankine cycle studies was assumed constant, while the current work allows the turbine isentropic efficiency to change (dynamic value) with both operating conditions and working fluids. Three-dimensional computational fluid dynamics analysis and multi-objective genetic algorithm optimization were performed using three-dimensional Reynolds-averaged Navier-Stokes equations with k-omega shear stress transport turbulence model in ANSYS"R"1"7-CFX and design exploration for various working fluids. The optimization was carried out using eight design parameters for the turbine stage geometry optimization including stator and rotor number of blades, rotor leading edge beta angle, trailing edge beta angle, stagger angle, throat width, trailing half wedge angle and shroud tip clearance. Results showed that

  12. Development of micro-scale axial and radial turbines for low-temperature heat source driven organic Rankine cycle

    International Nuclear Information System (INIS)

    Al Jubori, Ayad; Daabo, Ahmed; Al-Dadah, Raya K.; Mahmoud, Saad; Ennil, Ali Bahr

    2016-01-01

    . Such results are better than other studies in the literature and highlight the potential of the integrated approach for accurate prediction of the organic Rankine cycle performance based on micro-scale axial and radial-inflow turbines.

  13. Outcomes validity and reliability of the modified Rankin scale: implications for stroke clinical trials: a literature review and synthesis.

    Science.gov (United States)

    Banks, Jamie L; Marotta, Charles A

    2007-03-01

    The modified Rankin scale (mRS), a clinician-reported measure of global disability, is widely applied for evaluating stroke patient outcomes and as an end point in randomized clinical trials. Extensive evidence on the validity of the mRS exists across a large but fragmented literature. As new treatments for acute ischemic stroke are submitted for agency approval, an appreciation of the mRS's attributes, specifically its relationship to other stroke evaluation scales, would be valuable for decision-makers to properly assess the impact of a new drug on treatment paradigms. The purpose of this report is to assemble and systematically assess the properties of the mRS to provide decision-makers with pertinent evaluative information. A Medline search was conducted to identify reports in the peer-reviewed medical literature (1957-2006) that provide information on the structure, validation, scoring, and psychometric properties of the mRS and its use in clinical trials. The selection of articles was based on defined criteria that included relevance, study design and use of appropriate statistical methods. Of 224 articles identified by the literature search, 50 were selected for detailed assessment. Inter-rater reliability with the mRS is moderate and improves with structured interviews (kappa 0.56 versus 0.78); strong test-re-test reliability (kappa=0.81 to 0.95) has been reported. Numerous studies demonstrate the construct validity of the mRS by its relationships to physiological indicators such as stroke type, lesion size, perfusion and neurological impairment. Convergent validity between the mRS and other disability scales is well documented. Patient comorbidities and socioeconomic factors should be considered in properly applying and interpreting the mRS. Recent analyses suggest that randomized clinical trials of acute stroke treatments may require a smaller sample size if the mRS is used as a primary end point rather than the Barthel Index. Multiple types of evidence

  14. High-Efficiency Small-Scale Combined Heat and Power Organic Binary Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Costante Mario Invernizzi

    2018-04-01

    Full Text Available Small-CHP (Combined Heat and Power systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example they could play an important role in distributed generation even in developing countries or, in any case, where there are no extensive electricity networks. Traditionally the considered heat engines for micro- or mini-CHP are: the gas engine, the gas turbine (with internal combustion, the steam engine, engine working according to the Stirling and to the Rankine cycles, the last with organic fluids. In principle, also fuel cells could be used. In this paper, we focus on small size Rankine cycles (10–15 k W with organic working fluids. The assumed heat source is hot combustion gases at high temperature (900–950 ∘ C and we assume to use only single stages axial turbines. The need to work at high temperatures, limits the choice of the right organic working fluids. The calculation results show the limitation in the performances of simple cycles and suggest the opportunity to resort to complex (binary cycle configurations to achieve high net conversion efficiencies (15–16%.

  15. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    Science.gov (United States)

    2016-08-01

    efficiency by reducing energy consumption associated with electrical generation and reduces greenhouse gas emissions by increasing electrical generating...integrated system fuel economy test conditions This computation requires prediction of fuel consumption over baseline and integrated system load...EW-201251) Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

  16. Bottoming organic Rankine cycle for a small scale gas turbine: A comparison of different solutions

    International Nuclear Information System (INIS)

    Clemente, Stefano; Micheli, Diego; Reini, Mauro; Taccani, Rodolfo

    2013-01-01

    Highlights: ► The ORC bottoming section for a commercial micro gas turbine has been studied. ► Six different organic working fluids have been considered and compared. ► The preliminary designs of both axial and radial turbines have been developed. ► Also scroll and reciprocating expanders have been analyzed for comparison. ► The best suited machine has to be selected after a detailed analysis in each case. - Abstract: Recently, several efforts have been devoted to the improvement of the thermal efficiency of small gas turbines, in order to approach the typical values of the internal combustion engines in the same range of power. One possibility is represented by a combined cycle, obtained coupling the gas turbine to a bottoming organic Rankine cycle (ORC). This paper deals with the definition of the main features of an ORC system aimed to recover heat from a 100 kWe commercial gas turbine with internal recuperator. After the optimization of the thermodynamic cycles, involving a comparison between six working fluids, different expanders are analyzed, with the aim of detecting, if possible, the best suited machine. First, single stage turbines, in both radial and axial flow configuration, are designed specifically for each considered fluid, in particular investigating the opportunity of mounting the ORC expander directly on the high-speed shaft of the gas turbine. Then, the performances of these dynamic machines are compared with those of positive displacement expanders, such as scroll devices, obtainable from commercial HVAC compressor with minor revisions, and reciprocating ones, here newly designed

  17. The impact of component performance on the overall cycle performance of small-scale low temperature organic Rankine cycles

    Science.gov (United States)

    White, M.; Sayma, A. I.

    2015-08-01

    Low temperature organic Rankine cycles offer a promising technology for the generation of power from low temperature heat sources. Small-scale systems (∼10kW) are of significant interest, however there is a current lack of commercially viable expanders. For a potential expander to be economically viable for small-scale applications it is reasonable to assume that the same expander must have the ability to be implemented within a number of different ORC applications. It is therefore important to design and optimise the cycle considering the component performance, most notably the expander, both at different thermodynamic conditions, and using alternative organic fluids. This paper demonstrates a novel modelling methodology that combines a previously generated turbine performance map with cycle analysis to establish at what heat source conditions optimal system performance can be achieved using an existing turbine design. The results obtained show that the same turbine can be effectively utilised within a number of different ORC applications by changing the working fluid. By selecting suitable working fluids, this turbine can be used to convert pressurised hot water at temperatures between 360K and 400K, and mass flow rates between 0.45kg/s and 2.7kg/s, into useful power with outputs between 1.5kW and 27kW. This is a significant result since it allows the same turbine to be implemented into a variety of applications, improving the economy of scale. This work has also confirmed the suitability of the candidate turbine for a range of low temperature ORC applications.

  18. Improving the economy-of-scale of small organic rankine cycle systems through appropriate working fluid selection

    International Nuclear Information System (INIS)

    White, Martin; Sayma, Abdulnaser I.

    2016-01-01

    Highlights: • Novel system model coupling turbine and ORC system performance. • Contour plots to characterise working fluid and turbine performance. • Changing working fluid can expand pump and turbine operating envelope. • Possible to improve the economy-of-scale through optimal working fluid selection. - Abstract: Organic Rankine cycles (ORC) are becoming a major research area within the field of sustainable energy systems. However, a major challenge facing the widespread implementation of small and mini-scale ORC systems is the economy-of-scale. To overcome this challenge requires single components that can be manufactured in large volumes and then implemented into a wide variety of different applications where the heat source conditions may vary. The aim of this paper is to investigate whether working fluid selection can improve the current economy-of-scale by enabling the same system components to be used in multiple ORC systems. This is done through coupling analysis and optimisation of the energy process, with a performance map for a small-scale ORC radial turbine. The performance map, obtained using CFD, is adapted to account for additional loss mechanisms not accounted for in the original CFD simulation before being non-dimensionalised using a modified similitude theory developed for subsonic ORC turbines. The updated performance map is then implemented into a thermodynamic model, enabling the construction of a single performance contour that displays the range of heat source conditions that can be accommodated by the existing turbine whilst using a particular working fluid. Constructing this performance map for a range of working fluids, this paper demonstrates that through selecting a suitable working fluid, the same turbine can efficiently utilise heat sources between 360 and 400 K, with mass flow rates ranging between 0.5 and 2.75 kg/s respectively. This corresponds to using the same turbine in ORC applications where the heat available ranges

  19. Experimental performance of a piston expander in a small- scale organic Rankine cycle

    Science.gov (United States)

    Oudkerk, J. F.; Dickes, R.; Dumont, O.; Lemort, V.

    2015-08-01

    Volumetric expanders are suitable for more and more applications in the field of micro- and small-scale power system as waster heat recovery or solar energy. This paper present an experimental study carried out on a swatch-plate piston expander. The expander was integrated into an ORC test-bench using R245fa. The performances are evaluated in term of isentropic efficiency and filling factor. The maximum efficiency and power reached are respectively 53% and 2 kW. Inside cylinder pressure measurements allow to compute mechanical efficiency and drown P-V diagram. A semi-empirical simulation model is then proposed, calibrated and used to analyse the different sources of losses.

  20. Optimizing the performance of small-scale organic Rankine cycle that utilizes a single-screw expander

    International Nuclear Information System (INIS)

    Ziviani, D.; Gusev, S.; Lecompte, S.; Groll, E.A.; Braun, J.E.; Horton, W.T.; Broek, M. van den; De Paepe, M.

    2017-01-01

    Highlights: • A total of 102 steady-state points with R245fa and SES336 have been collected. • R245fa led to 10% higher power output despite lower expander isentropic efficiency. • The ORC running with SES36 presented a better matching between expander and cycle. • The theoretical matching between expander volume ratio and cycle efficiency is determined. • Steady-state performance maps are used to build a feed-forward controller. - Abstract: This paper deals with the operation and optimization of a down-scaled industrial organic Rankine cycle (ORC) for low-grade waste heat recovery. The system is a sub-critical regenerative ORC with a nominal power output of 11 kW. The ORC unit has been assembled using off-the-shelf components including three identical plate heat exchangers, a liquid receiver, a multi-stage centrifugal pump and a single-screw compressor adapted to operate as an expander. The experimental results are used to evaluate the influence of the expander performance on the behavior of the ORC system at nominal and part-load conditions. The matching between the volumetric expander and the system operating conditions is also analyzed. Results showed that in the case of SES36, both the expander efficiency and system performance were maximized for a pressure ratio between 7 and 9. In the case of R245fa, while the system efficiency achieved values similar to SES36, but the expander maximum isentropic efficiency was 17% lower. Two analyses are carried out to optimize the operation of the ORC unit with R245fa. At first, the insights gained by analyzing the experimental data are used to evaluate the theoretical matching between volumetric expander and the system maximum efficiency in terms of the Second Law of thermodynamics. Secondly, a control-oriented steady-state cycle model based on empirical correlations calibrated on the experimental results is developed. The model is used to implement a feed-forward control strategy based on predetermined steady

  1. Conditional Standard Errors of Measurement for Scale Scores.

    Science.gov (United States)

    Kolen, Michael J.; And Others

    1992-01-01

    A procedure is described for estimating the reliability and conditional standard errors of measurement of scale scores incorporating the discrete transformation of raw scores to scale scores. The method is illustrated using a strong true score model, and practical applications are described. (SLD)

  2. Clinical scoring scales in thyroidology: A compendium

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2011-01-01

    Full Text Available This compendium brings together traditional as well as contemporary scoring and grading systems used for the screening and diagnosis of various thyroid diseases, dysfunctions, and complications. The article discusses scores used to help diagnose hypo-and hyperthyroidism, to grade and manage goiter and ophthalmopathy, and to assess the risk of thyroid malignancy.

  3. Facilitating the Interpretation of English Language Proficiency Scores: Combining Scale Anchoring and Test Score Mapping Methodologies

    Science.gov (United States)

    Powers, Donald; Schedl, Mary; Papageorgiou, Spiros

    2017-01-01

    The aim of this study was to develop, for the benefit of both test takers and test score users, enhanced "TOEFL ITP"® test score reports that go beyond the simple numerical scores that are currently reported. To do so, we applied traditional scale anchoring (proficiency scaling) to item difficulty data in order to develop performance…

  4. Energy, Exergy and Performance Analysis of Small-Scale Organic Rankine Cycle Systems for Electrical Power Generation Applicable in Rural Areas of Developing Countries

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-01-01

    Full Text Available This paper introduces the concept of installing a small-scale organic Rankine cycle system for the generation of electricity in remote areas of developing countries. The Organic Rankine Cycle Systems (ORC system uses a commercial magnetically-coupled scroll expander, plate type heat exchangers and plunger type working fluid feed pump. The heat source for the ORC system can be solar energy. A series of laboratory tests were conducted to confirm the cycle efficiency and expander power output of the system. Using the actual system data, the exergy destruction on the system components and exergy efficiency were assessed. Furthermore, the results of the variations of system energy and exergy efficiencies with different operating parameters, such as the evaporating and condensing pressures, degree of superheating, dead state temperature, expander inlet temperature and pressure ratio were illustrated. The system exhibited acceptable operational characteristics with good performance under a wide range of conditions. A heat source temperature of 121 °C is expected to deliver a power output of approximately 1.4 kW. In addition, the system cost analysis and financing mechanisms for the installation of the ORC system were discussed.

  5. Adopting a Patient-Centered Approach to Primary Outcome Analysis of Acute Stroke Trials by Use of a Utility-Weighted Modified Rankin Scale

    Science.gov (United States)

    Chaisinanunkul, Napasri; Adeoye, Opeolu; Lewis, Roger J.; Grotta, James C.; Broderick, Joseph; Jovin, Tudor G.; Nogueira, Raul G.; Elm, Jordan; Graves, Todd; Berry, Scott; Lees, Kennedy R.; Barreto, Andrew D.; Saver, Jeffrey L.

    2015-01-01

    Background and Purpose Although the modified Rankin Scale (mRS) is the most commonly employed primary endpoint in acute stroke trials, its power is limited when analyzed in dichotomized fashion and its indication of effect size challenging to interpret when analyzed ordinally. Weighting the seven Rankin levels by utilities may improve scale interpretability while preserving statistical power. Methods A utility weighted mRS (UW-mRS) was derived by averaging values from time-tradeoff (patient centered) and person-tradeoff (clinician centered) studies. The UW-mRS, standard ordinal mRS, and dichotomized mRS were applied to 11 trials or meta-analyses of acute stroke treatments, including lytic, endovascular reperfusion, blood pressure moderation, and hemicraniectomy interventions. Results Utility values were: mRS 0–1.0; mRS 1 - 0.91; mRS 2 - 0.76; mRS 3 - 0.65; mRS 4 - 0.33; mRS 5 & 6 - 0. For trials with unidirectional treatment effects, the UW-mRS paralleled the ordinal mRS and outperformed dichotomous mRS analyses. Both the UW-mRS and the ordinal mRS were statistically significant in six of eight unidirectional effect trials, while dichotomous analyses were statistically significant in two to four of eight. In bidirectional effect trials, both the UW-mRS and ordinal tests captured the divergent treatment effects by showing neutral results whereas some dichotomized analyses showed positive results. Mean utility differences in trials with statistically significant positive results ranged from 0.026 to 0.249. Conclusion A utility-weighted mRS performs similarly to the standard ordinal mRS in detecting treatment effects in actual stroke trials and ensures the quantitative outcome is a valid reflection of patient-centered benefits. PMID:26138130

  6. Factor Structure of Child Behavior Scale Scores in Peruvian Preschoolers

    Science.gov (United States)

    Meyer, Erin L.; Schaefer, Barbara A.; Soto, Cesar Merino; Simmons, Crystal S.; Anguiano, Rebecca; Brett, Jeremy; Holman, Alea; Martin, Justin F.; Hata, Heidi K.; Roberts, Kimberly J.; Mello, Zena R.; Worrell, Frank C.

    2011-01-01

    Behavior rating scales aid in the identification of problem behaviors, as well as the development of interventions to reduce such behavior. Although scores on many behavior rating scales have been validated in the United States, there have been few such studies in other cultural contexts. In this study, the structural validity of scores on a…

  7. Preliminary Development of a Free Piston Expander–Linear Generator for Small-Scale Organic Rankine Cycle (ORC Waste Heat Recovery System

    Directory of Open Access Journals (Sweden)

    Gaosheng Li

    2016-04-01

    Full Text Available A novel free piston expander-linear generator (FPE-LG integrated unit was proposed to recover waste heat efficiently from vehicle engine. This integrated unit can be used in a small-scale Organic Rankine Cycle (ORC system and can directly convert the thermodynamic energy of working fluid into electric energy. The conceptual design of the free piston expander (FPE was introduced and discussed. A cam plate and the corresponding valve train were used to control the inlet and outlet valve timing of the FPE. The working principle of the FPE-LG was proven to be feasible using an air test rig. The indicated efficiency of the FPE was obtained from the p–V indicator diagram. The dynamic characteristics of the in-cylinder flow field during the intake and exhaust processes of the FPE were analyzed based on Fluent software and 3D numerical simulation models using a computation fluid dynamics method. Results show that the indicated efficiency of the FPE can reach 66.2% and the maximal electric power output of the FPE-LG can reach 22.7 W when the working frequency is 3 Hz and intake pressure is 0.2 MPa. Two large-scale vortices are formed during the intake process because of the non-uniform distribution of velocity and pressure. The vortex flow will convert pressure energy and kinetic energy into thermodynamic energy for the working fluid, which weakens the power capacity of the working fluid.

  8. Energy, Exergy and Economic Evaluation Comparison of Small-Scale Single and Dual Pressure Organic Rankine Cycles Integrated with Low-Grade Heat Sources

    Directory of Open Access Journals (Sweden)

    Armando Fontalvo

    2017-09-01

    Full Text Available Low-grade heat sources such as solar thermal, geothermal, exhaust gases and industrial waste heat are suitable alternatives for power generation which can be exploited by means of small-scale Organic Rankine Cycle (ORC. This paper combines thermodynamic optimization and economic analysis to assess the performance of single and dual pressure ORC operating with different organic fluids and targeting small-scale applications. Maximum power output is lower than 45 KW while the temperature of the heat source varies in the range 100–200 °C. The studied working fluids, namely R1234yf, R1234ze(E and R1234ze(Z, are selected based on environmental, safety and thermal performance criteria. Levelized Cost of Electricity (LCOE and Specific Investment Cost (SIC for two operation conditions are presented: maximum power output and maximum thermal efficiency. Results showed that R1234ze(Z achieves the highest net power output (up to 44 kW when net power output is optimized. Regenerative ORC achieves the highest performance when thermal efficiency is optimized (up to 18%. Simple ORC is the most cost-effective among the studied cycle configurations, requiring a selling price of energy of 0.3 USD/kWh to obtain a payback period of 8 years. According to SIC results, the working fluid R1234ze(Z exhibits great potential for simple ORC when compared to conventional R245fa.

  9. Experimental Assessment of a Helical Coil Heat Exchanger Operating at Subcritical and Supercritical Conditions in a Small-Scale Solar Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2017-05-01

    Full Text Available In this study, the performance of a helical coil heat exchanger operating at subcritical and supercritical conditions is analysed. The counter-current heat exchanger was specially designed to operate at a maximal pressure and temperature of 42 bar and 200 °C, respectively. The small-scale solar organic Rankine cycle (ORC installation has a net power output of 3 kWe. The first tests were done in a laboratory where an electrical heater was used instead of the concentrated photovoltaic/thermal (CPV/T collectors. The inlet heating fluid temperature of the water was 95 °C. The effects of different parameters on the heat transfer rate in the heat exchanger were investigated. Particularly, the performance analysis was elaborated considering the changes of the mass flow rate of the working fluid (R-404A in the range of 0.20–0.33 kg/s and the inlet pressure varying from 18 bar up to 41 bar. Hence, the variation of the heat flux was in the range of 5–9 kW/m2. The results show that the working fluid’s mass flow rate has significant influence on the heat transfer rate rather than the operational pressure. Furthermore, from the comparison between the experimental results with the heat transfer correlations from the literature, the experimental results fall within the uncertainty range for the supercritical analysis but there is a deviation of the investigated subcritical correlations.

  10. National Institutes of Health Stroke Scale-Time Score Predicts Outcome after Endovascular Therapy in Acute Ischemic Stroke: A Retrospective Single-Center Study.

    Science.gov (United States)

    Todo, Kenichi; Sakai, Nobuyuki; Kono, Tomoyuki; Hoshi, Taku; Imamura, Hirotoshi; Adachi, Hidemitsu; Kohara, Nobuo

    2016-05-01

    Outcomes after successful endovascular therapy in acute ischemic stroke are associated with onset-to-reperfusion time (ORT) and the National Institutes of Health Stroke Scale (NIHSS) score. In intravenous recombinant tissue plasminogen activator therapy, the NIHSS-time score, calculated by multiplying onset-to-treatment time with the NIHSS score, has been shown to predict clinical outcomes. In this study, we assessed whether a similar combination of the ORT and the NIHSS score can be applied to predict the outcomes after endovascular therapy. We retrospectively reviewed the charts of 128 consecutive ischemic stroke patients with successful reperfusion after endovascular therapy. We analyzed the association of the ORT, the NIHSS score, and the NIHSS-time score with good outcome (modified Rankin Scale score ≤ 2 at 3 months). Good outcome rates for patients with NIHSS-time scores of 84.7 or lower, scores higher than 84.7 up to 127.5 or lower, and scores higher than 127.5 were 72.1%, 44.2%, and 14.3%, respectively (P < .01). Multivariate logistic regression analysis revealed that the NIHSS-time score was an independent predictor of good outcomes (odds ratio, .372; 95% confidence interval, .175-.789) after adjusting for age, sex, internal carotid artery occlusion, plasma glucose level, ORT, and NIHSS score. The NIHSS-time score can predict good clinical outcomes after endovascular treatment. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  11. Low-Concentration Solar-Power Systems Based on Organic Rankine Cycles for Distributed-Scale Applications: Overview and Further Developments

    Energy Technology Data Exchange (ETDEWEB)

    Markides, Christos N., E-mail: c.markides@imperial.ac.uk [Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London, London (United Kingdom)

    2015-12-10

    This paper is concerned with the emergence and development of low-to-medium-grade thermal-energy-conversion systems for distributed power generation based on thermodynamic vapor-phase heat-engine cycles undergone by organic working fluids, namely organic Rankine cycles (ORCs). ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low/medium-grade heat (at temperatures up to ~300–400°C) to useful work, at an output power scale from a few kilowatts to 10s of megawatts. Thermal efficiencies in excess of 25% are achievable at higher temperatures and larger scales, and efforts are currently in progress to improve the overall economic viability and thus uptake of ORC power systems, by focusing on advanced architectures, working-fluid selection, heat exchangers and expansion machines. Solar-power systems based on ORC technology have a significant potential to be used for distributed power generation, by converting thermal energy from simple and low-cost non-concentrated or low-concentration collectors to mechanical, hydraulic, or electrical energy. Current fields of use include mainly geothermal and biomass/biogas, as well as the recovery and conversion of waste heat, leading to improved energy efficiency, primary energy (i.e., fuel) use and emission minimization, yet the technology is highly transferable to solar-power generation as an affordable alternative to small-to-medium-scale photovoltaic systems. Solar-ORC systems offer naturally the advantages of providing a simultaneous thermal-energy output for hot water provision and/or space heating, and the particularly interesting possibility of relatively straightforward onsite (thermal) energy storage. Key performance characteristics are presented, and important heat transfer effects that act to limit performance are identified as noteworthy directions of future research for the further development of this technology.

  12. Low-Concentration Solar-Power Systems based on Organic Rankine Cycles for Distributed-Scale Applications:Overview and Further Developments

    Directory of Open Access Journals (Sweden)

    Christos N. Markides

    2015-12-01

    Full Text Available This paper is concerned with the emergence and development of low- to medium-grade thermal-energy conversion systems for distributed power generation based on thermodynamic vapour-phase heat-engine cycles undergone by organic working-fluids, namely organic Rankine cycles (ORCs. ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low-/medium-grade heat (at temperatures up to ~ 300 – 400 °C to useful work, at an output power scale from a few kW to 10s of MW. Thermal efficiencies in excess of 25% are achievable at higher temperatures and larger scales, and efforts are currently in progress to improve the overall economic viability, and thus uptake, of ORC power systems by focusing on advanced architectures, working-fluid selection, heat exchangers and expansion machines. Solar-power systems based on ORC technology have a significant potential to be used for distributed power generation, by converting thermal energy from simple and low-cost non-concentrated or low-concentration collectors to mechanical, hydraulic or electrical energy. Current fields of use include mainly geothermal and biomass/biogas, as well as the recovery and conversion of waste heat, leading to improved energy efficiency, primary energy (i.e. fuel use and emission minimization, yet the technology is highly transferable to solar power generation as an affordable alternative to small- to medium-scale photovoltaic (PV systems. Solar-ORC systems offer naturally the advantages of providing a simultaneous thermal-energy output for hot water provision and/or space heating, and the particularly interesting possibility of relatively straightforward on-site (thermal energy storage. Key performance characteristics are presented, and important heat transfer effects that act to limit performance are identified as noteworthy directions of future research for the further development of this technology.

  13. Low-Concentration Solar-Power Systems Based on Organic Rankine Cycles for Distributed-Scale Applications: Overview and Further Developments

    International Nuclear Information System (INIS)

    Markides, Christos N.

    2015-01-01

    This paper is concerned with the emergence and development of low-to-medium-grade thermal-energy-conversion systems for distributed power generation based on thermodynamic vapor-phase heat-engine cycles undergone by organic working fluids, namely organic Rankine cycles (ORCs). ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low/medium-grade heat (at temperatures up to ~300–400°C) to useful work, at an output power scale from a few kilowatts to 10s of megawatts. Thermal efficiencies in excess of 25% are achievable at higher temperatures and larger scales, and efforts are currently in progress to improve the overall economic viability and thus uptake of ORC power systems, by focusing on advanced architectures, working-fluid selection, heat exchangers and expansion machines. Solar-power systems based on ORC technology have a significant potential to be used for distributed power generation, by converting thermal energy from simple and low-cost non-concentrated or low-concentration collectors to mechanical, hydraulic, or electrical energy. Current fields of use include mainly geothermal and biomass/biogas, as well as the recovery and conversion of waste heat, leading to improved energy efficiency, primary energy (i.e., fuel) use and emission minimization, yet the technology is highly transferable to solar-power generation as an affordable alternative to small-to-medium-scale photovoltaic systems. Solar-ORC systems offer naturally the advantages of providing a simultaneous thermal-energy output for hot water provision and/or space heating, and the particularly interesting possibility of relatively straightforward onsite (thermal) energy storage. Key performance characteristics are presented, and important heat transfer effects that act to limit performance are identified as noteworthy directions of future research for the further development of this technology.

  14. Automatic scoring of the severity of psoriasis scaling

    DEFF Research Database (Denmark)

    Gomez, David Delgado; Ersbøll, Bjarne Kjær; Carstensen, Jens Michael

    2004-01-01

    In this work, a combined statistical and image analysis method to automatically evaluate the severity of scaling in psoriasis lesions is proposed. The method separates the different regions of the disease in the image and scores the degree of scaling based on the properties of these areas. The pr...... with scores made by doctors. This and the fact that the obtained measures are continuous indicate the proposed method is a suitable tool to evaluate the lesion and to track the evolution of dermatological diseases....

  15. The Impact of Emotional Priming on MMPI-2 Scale Scores

    Science.gov (United States)

    Lee, Tayla T. C.; Forbey, Johnathan D.; Ritchey, Kristin A.

    2011-01-01

    The current study investigated potential emotional priming effects on Minnesota Multiphasic Personality Inventory-2 (MMPI-2) scale scores. Participants included 98 college students who completed a personal narrative intended to induce temporary mood states, the MMPI-2, and a mood rating inventory. Results of the mood manipulation indicated that…

  16. Characterizing Sources of Uncertainty in Item Response Theory Scale Scores

    Science.gov (United States)

    Yang, Ji Seung; Hansen, Mark; Cai, Li

    2012-01-01

    Traditional estimators of item response theory scale scores ignore uncertainty carried over from the item calibration process, which can lead to incorrect estimates of the standard errors of measurement (SEMs). Here, the authors review a variety of approaches that have been applied to this problem and compare them on the basis of their statistical…

  17. Stroke scale score and early prediction of outcome after stroke

    International Nuclear Information System (INIS)

    Ahmed, R.; Zuberi, F.Z.; Afsar, S.

    2004-01-01

    Objective: To evaluate the baseline National Institute of Health Stroke Scale (NIHSS) score as a predictor of functional outcome after ischemic stroke. Subjects and Methods: The study included 50 patients who presented to Civil Hospital, Karachi, during the study period with acute stroke and were evaluated with CT scan of brain. Only those patients were enrolled in the study that had acute ischemic stroke. The enrolled subjects were then evaluated for the neurological impairment using National Institute of Health Stroke Scale (NIHSS). The subjects were followed-up and their functional outcome was assessed using Barthel index (BI) on the 7th day of their admission. Results: Of the fifty patients enrolled in the study, 31 (62%) were males and 19 (38%) were females, with age ranging from 45 years to 95 years and a mean age of 59.9 years. Neurological impairment at presentation was assessed by NIHSS. The score ranged between 2 and 28. The functional outcome was evaluated on the 7th day using Barthel index (BI), which ranged from 0 to 80. NIHSS score was found to be a good predictor of functional outcome in patients with ischemic stroke (p<0.001). Other factors like gender, hypertension and heart disease did not affect the functional recovery in such patients. Various factors were found to be significant for early prediction of stroke recovery. The NIHSS score was the strongest predictor of outcome after ischemic stroke. Age at the time of the event was also found to be an important predictor for stroke recovery. Conclusion: The NIHSS score is a good predictor of patient's recovery after stroke. Assessing the patient's neurological impairment at first presentation of ischemic stroke can guide the physician regarding the prognosis and management plan. (author)

  18. [Circadian rhythm : Influence on Epworth Sleepiness Scale score].

    Science.gov (United States)

    Herzog, M; Bedorf, A; Rohrmeier, C; Kühnel, T; Herzog, B; Bremert, T; Plontke, S; Plößl, S

    2017-02-01

    The Epworth Sleepiness Scale (ESS) is frequently used to determine daytime sleepiness in patients with sleep-disordered breathing. It is still unclear whether different levels of alertness induced by the circadian rhythm influence ESS score. The aim of this study is to investigate the influence of circadian rhythm-dependent alertness on ESS performance. In a monocentric prospective noninterventional observation study, 97 patients with suspected sleep-disordered breathing were investigated with respect to daytime sleepiness in temporal relationship to polysomnographic examination and treatment. The Karolinska Sleepiness Scale (KSS) and the Stanford Sleepiness Scale (SSS) served as references for the detection of present sleepiness at three different measurement times (morning, noon, evening), prior to and following a diagnostic polysomnography night as well as after a continuous positive airway pressure (CPAP) titration night (9 measurements in total). The KSS, SSS, and ESS were performed at these times in a randomized order. The KSS and SSS scores revealed a circadian rhythm-dependent curve with increased sleepiness at noon and in the evening. Following a diagnostic polysomnography night, the scores were increased compared to the measurements prior to the night. After the CPAP titration night, sleepiness in the morning was reduced. KSS and SSS reflect the changes in alertness induced by the circadian rhythm. The ESS score war neither altered by the intra-daily nor by the inter-daily changes in the level of alertness. According to the present data, the ESS serves as a reliable instrument to detect the level of daytime sleepiness independently of the circadian rhythm-dependent level of alertness.

  19. River Discharge and Local Scale Habitat Influence LIFE Score Macroinvertebrate LIFE Scores

    DEFF Research Database (Denmark)

    Dunbar, Michael J.; Pedersen, Morten Lauge; Cadman, Dan

    2010-01-01

    Midlands of the U.K., we describe how local-scale habitat features (indexed through River Habitat Survey or Danish Habitat Quality Survey) and changing river flow (discharge) influence the response of a macroinvertebrate community index. The approach has broad applicability in developing regional flow...... Invertebrate index for Flow Evaluation (LIFE), an average of abundance-weighted flow groups which indicate the microhabitat preferences of each taxon for higher velocities and clean gravel/cobble substrata or slow/still velocities and finer substrata. 3. For the Danish fauna, the LIFE score responded to three...... of the channel (negative). In both cases, LIFE responded negatively to features associated with historical channel modification. We suggest that there are several mechanisms for these relationships, including the narrower tolerances of taxa preferring high velocity habitat; these taxa are also continually...

  20. Design and simulation of a prototype of a small-scale solar CHP system based on evacuated flat-plate solar collectors and Organic Rankine Cycle

    International Nuclear Information System (INIS)

    Calise, Francesco; D’Accadia, Massimo Dentice; Vicidomini, Maria; Scarpellino, Marco

    2015-01-01

    Highlights: • A novel small scale solar power plant was designed and simulated. • The system is based on evacuated solar thermal collectors and an ORC system. • An average electric efficiency of 10% was found for the ORC. • The efficiency of solar collectors was found to be high in summer (>50%). • Pay-back periods lower than 5 years were estimated, in case of public funding. - Abstract: This paper presents a dynamic simulation model of a novel prototype of a 6 kW e solar power plant. The system is based on the coupling of innovative solar thermal collectors with a small Organic Rankine Cycle (ORC), simultaneously producing electric energy and low temperature heat. The novelty of the proposed system lies in the solar collector field, which is based on stationary evacuated flat-plate solar thermal collectors capable to achieve the operating temperatures typical of the concentrating solar thermal collectors. The solar field consists of about 73.5 m 2 of flat-plate evacuated solar collectors, heating a diathermic oil up to a maximum temperature of 230 °C. A diathermic oil storage tank is employed in order to mitigate the fluctuations due to the variability of solar energy availability. The hot diathermic oil exiting from the tank passes through an auxiliary gas-fired burner which provides eventual additional thermal energy. The inlet temperature of the diathermic oil entering the ORC system varies as a function of the availability of solar energy, also determining an oscillating response of the ORC. The ORC was simulated in Engineering Equation Solver (EES), using zero-dimensional energy and mass balances. The ORC model was subsequently implemented in a more general TRNSYS model, including all the remaining components of the system. The model was used to evaluate the energy and economic performance of the solar CHP system under analysis, in different climatic conditions. The results show that the efficiency of the ORC does not significantly vary during the

  1. Ammonia-water Rankine cycle

    International Nuclear Information System (INIS)

    Bo Hanliang; Ma Changwen; Wu Shaorong

    1997-01-01

    On characteristics of heating source and cooling source in nuclear heating reactor cooperation, the authors advance a new kind of power cycle in which a multicomponent mixture as the work fluid, ammonia-water Rankine cycle, describe its running principle, and compare it with steam Rankine cycle in the same situation. The result is that: the new kind of power cycle, ammonia-water Rankine cycle has higher electricity efficiency; it suits for the situation of heating source and cooling source which offered by nuclear heating reactor cooperation. For low temperature heating source, it maybe has a widely application

  2. Working Fluid Stability in Large-Scale Organic Rankine Cycle-Units Using Siloxanes—Long-Term Experiences and Fluid Recycling

    Directory of Open Access Journals (Sweden)

    Tobias G. Erhart

    2016-05-01

    Full Text Available The results in this work show the influence of long-term operation on the decomposition of working fluids in eight different organic rankine cycle (ORC power plants (both heat-led and electricity-led in a range of 900 kW el to 2 MW el . All case study plants are using octamethyltrisiloxane (MDM as a working fluid; the facilities are between six to 12 years old. Detailed analyses, including the fluid distribution throughout the cycle, are conducted on one system. All presented fluid samples are analyzed via head space gas chromatography mass spectrometry (HS-GC-MS. Besides the siloxane composition, the influence of contaminants, such as mineral oil-based lubricants (and their components, is examined. In most cases, the original working fluid degrades to fractions of siloxanes with a lower boiling point (low boilers and fractions with a higher boiling point (high boilers. As a consequence of the analyses, a new fluid recycling and management system was designed and tested in one case study plant (Case Study #8. Pre-post comparisons of fluid samples prove the effectiveness of the applied methods. The results show that the recovery of used working fluid offers an alternative to the purchase of fresh fluid, since operating costs can be significantly reduced. For large facilities, the prices for new fluid range from € 15 per liter (in 2006 to € 22 per liter (in 2013, which is a large reinvestment, especially in light of filling volumes of 4000 liters to 7000 liters per unit. Using the aforementioned method, a price of € 8 per liter of recovered MDM can be achieved.

  3. The SCSTPE organic Rankine engine

    Science.gov (United States)

    Boda, F. P.

    1980-01-01

    The organic Rankine cycle engine under consideration for a solar thermal system being developed is described. Design parameters, method of control, performance and cost data are provided for engine power levels up to 80 kWe; efficiency is shown as a function of turbine inlet temperature in the range of 149 C to 427 C.

  4. Reliability Generalization: Exploring Variation of Reliability Coefficients of MMPI Clinical Scales Scores.

    Science.gov (United States)

    Vacha-Haase, Tammi; Kogan, Lori R.; Tani, Crystal R.; Woodall, Renee A.

    2001-01-01

    Used reliability generalization to explore the variance of scores on 10 Minnesota Multiphasic Personality Inventory (MMPI) clinical scales drawing on 1,972 articles in the literature on the MMPI. Results highlight the premise that scores, not tests, are reliable or unreliable, and they show that study characteristics do influence scores on the…

  5. Multiple scaling behaviour and nonlinear traits in music scores

    Science.gov (United States)

    González-Espinoza, Alfredo; Larralde, Hernán; Martínez-Mekler, Gustavo; Müller, Markus

    2017-12-01

    We present a statistical analysis of music scores from different composers using detrended fluctuation analysis (DFA). We find different fluctuation profiles that correspond to distinct autocorrelation structures of the musical pieces. Further, we reveal evidence for the presence of nonlinear autocorrelations by estimating the DFA of the magnitude series, a result validated by a corresponding study of appropriate surrogate data. The amount and the character of nonlinear correlations vary from one composer to another. Finally, we performed a simple experiment in order to evaluate the pleasantness of the musical surrogate pieces in comparison with the original music and find that nonlinear correlations could play an important role in the aesthetic perception of a musical piece.

  6. Normal variability of children's scaled scores on subtests of the Dutch Wechsler Preschool and Primary scale of Intelligence - third edition.

    Science.gov (United States)

    Hurks, P P M; Hendriksen, J G M; Dek, J E; Kooij, A P

    2013-01-01

    Intelligence tests are included in millions of assessments of children and adults each year (Watkins, Glutting, & Lei, 2007a , Applied Neuropsychology, 14, 13). Clinicians often interpret large amounts of subtest scatter, or large differences between the highest and lowest scaled subtest scores, on an intelligence test battery as an index for abnormality or cognitive impairment. The purpose of the present study is to characterize "normal" patterns of variability among subtests of the Dutch Wechsler Preschool and Primary Scale of Intelligence - Third Edition (WPPSI-III-NL; Wechsler, 2010 ). Therefore, the frequencies of WPPSI-III-NL scaled subtest scatter were reported for 1039 healthy children aged 4:0-7:11 years. Results indicated that large differences between highest and lowest scaled subtest scores (or subtest scatter) were common in this sample. Furthermore, degree of subtest scatter was related to: (a) the magnitude of the highest scaled subtest score, i.e., more scatter was seen in children with the highest WPPSI-III-NL scaled subtest scores, (b) Full Scale IQ (FSIQ) scores, i.e., higher FSIQ scores were associated with an increase in subtest scatter, and (c) sex differences, with boys showing a tendency to display more scatter than girls. In conclusion, viewing subtest scatter as an index for abnormality in WPPSI-III-NL scores is an oversimplification as this fails to recognize disparate subtest heterogeneity that occurs within a population of healthy children aged 4:0-7:11 years.

  7. Thermo-economic analysis and selection of working fluid for solar organic Rankine cycle

    International Nuclear Information System (INIS)

    Desai, Nishith B.; Bandyopadhyay, Santanu

    2016-01-01

    Highlights: • Concentrating solar power plant with organic Rankine cycle. • Thermo-economic analysis of solar organic Rankine cycle. • Performance evaluation for different working fluids. • Comparison diagram to select appropriate working fluid. - Graphical Abstract: Display Omitted - Abstract: Organic Rankine cycle (ORC), powered by line-focusing concentrating solar collectors (parabolic trough collector and linear Fresnel reflector), is a promising option for modular scale. ORC based power block, with dry working fluids, offers higher design and part-load efficiencies compared to steam Rankine cycle (SRC) in small-medium scale, with temperature sources up to 400 °C. However, the cost of ORC power block is higher compared to the SRC power block. Similarly, parabolic trough collector (PTC) system has higher optical efficiency and higher cost compared to linear Fresnel reflector (LFR) system. The thermodynamic efficiencies and power block costs also vary with working fluids of the Rankine cycle. In this paper, thermo-economic comparisons of organic Rankine and steam Rankine cycles powered by line-focusing concentrating solar collectors are reported. A simple selection methodology, based on thermo-economic analysis, and a comparison diagram for working fluids of power generating cycles are also proposed. Concentrating solar power plants with any collector technology and any power generating cycle can be compared using the proposed methodology.

  8. A Reliability Generalization Study of Scores on Rotter's and Nowicki-Strickland's Locus of Control Scales

    Science.gov (United States)

    Beretvas, S. Natasha; Suizzo, Marie-Anne; Durham, Jennifer A.; Yarnell, Lisa M.

    2008-01-01

    The most commonly used measures of locus of control are Rotter's Internality-Externality Scale (I-E) and Nowicki and Strickland's Internality-Externality Scale (NSIE). A reliability generalization study is conducted to explore variability in I-E and NSIE score reliability. Studies are coded for aspects of the scales used (number of response…

  9. Rankine cycle system and method

    Science.gov (United States)

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-09-09

    A Rankine cycle waste heat recovery system uses a receiver with a maximum liquid working fluid level lower than the minimum liquid working fluid level of a sub-cooler of the waste heat recovery system. The receiver may have a position that is physically lower than the sub-cooler's position. A valve controls transfer of fluid between several of the components in the waste heat recovery system, especially from the receiver to the sub-cooler. The system may also have an associated control module.

  10. Psychometric Properties of Raw and Scale Scores on Mixed-Format Tests

    Science.gov (United States)

    Kolen, Michael J.; Lee, Won-Chan

    2011-01-01

    This paper illustrates that the psychometric properties of scores and scales that are used with mixed-format educational tests can impact the use and interpretation of the scores that are reported to examinees. Psychometric properties that include reliability and conditional standard errors of measurement are considered in this paper. The focus is…

  11. Comparing the MMPI-2 Scale Scores of Parents Involved in Parental Competency and Child Custody Assessments

    Science.gov (United States)

    Resendes, John; Lecci, Len

    2012-01-01

    MMPI-2 scores from a parent competency sample (N = 136 parents) are compared with a previously published data set of MMPI-2 scores for child custody litigants (N = 508 parents; Bathurst et al., 1997). Independent samples t tests yielded significant and in some cases substantial differences on the standard MMPI-2 clinical scales (especially Scales…

  12. A comparative study on assessment procedures and metric properties of two scoring systems of the Coma Recovery Scale-Revised items: standard and modified scores.

    Science.gov (United States)

    Sattin, Davide; Lovaglio, Piergiorgio; Brenna, Greta; Covelli, Venusia; Rossi Sebastiano, Davide; Duran, Dunja; Minati, Ludovico; Giovannetti, Ambra Mara; Rosazza, Cristina; Bersano, Anna; Nigri, Anna; Ferraro, Stefania; Leonardi, Matilde

    2017-09-01

    The study compared the metric characteristics (discriminant capacity and factorial structure) of two different methods for scoring the items of the Coma Recovery Scale-Revised and it analysed scale scores collected using the standard assessment procedure and a new proposed method. Cross sectional design/methodological study. Inpatient, neurological unit. A total of 153 patients with disorders of consciousness were consecutively enrolled between 2011 and 2013. All patients were assessed with the Coma Recovery Scale-Revised using standard (rater 1) and inverted (rater 2) procedures. Coma Recovery Scale-Revised score, number of cognitive and reflex behaviours and diagnosis. Regarding patient assessment, rater 1 using standard and rater 2 using inverted procedures obtained the same best scores for each subscale of the Coma Recovery Scale-Revised for all patients, so no clinical (and statistical) difference was found between the two procedures. In 11 patients (7.7%), rater 2 noted that some Coma Recovery Scale-Revised codified behavioural responses were not found during assessment, although higher response categories were present. A total of 51 (36%) patients presented the same Coma Recovery Scale-Revised scores of 7 or 8 using a standard score, whereas no overlap was found using the modified score. Unidimensionality was confirmed for both score systems. The Coma Recovery Scale Modified Score showed a higher discriminant capacity than the standard score and a monofactorial structure was also supported. The inverted assessment procedure could be a useful evaluation method for the assessment of patients with disorder of consciousness diagnosis.

  13. Which clinical variable influences health-related quality of life the most after spontaneous subarachnoid hemorrhage? Hunt and Hess scale, Fisher score, World Federation of Neurosurgeons score, Brussels coma score, and Glasgow coma score compared.

    Science.gov (United States)

    Kapapa, Thomas; Tjahjadi, Martin; König, Ralph; Wirtz, Christian Rainer; Woischneck, Dieter

    2013-12-01

    To determine the strength of the correlation between the Hunt and Hess scale, Fisher score, Brussels coma score, World Federation of Neurosurgeons score, and Glasgow coma score and health-related quality of life. Evaluable questionnaires from 236 patients (5.6 years [± standard deviation, 2.854 years] on average after hemorrhage) were included in the analysis. Quality of life was documented using the MOS-36 item short form health survey. Because of the ordinal nature of the variables, Kendall tau was used for calculation. Significance was established as P ≤ 0.05. Weak and very weak correlations were found in general (r ≤ 0.28). The strongest correlations were found between the Glasgow coma score and quality of life (r = 0.236, P = 0.0001). In particular, the "best verbal response" achieved the strongest correlations in the comparison, at r = 0.28/P = 0.0001. The Fisher score showed very weak correlations (r = -0.148/P = 0.012). The Brussels coma score (r = -0.216/P = 0.0001), Hunt and Hess scale (r = -0.197/P = 0.0001), and the World Federation of Neurosurgeons score (r = -0.185/P = 0.0001) revealed stronger correlations, especially in terms of the physical aspects of quality of life. The Glasgow coma scale revealed the strongest, and the Fisher score showed the weakest correlations. Thus the Fisher score, as an indicator of the severity of a hemorrhage, has little significance in terms of health-related quality of life. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Validation of patient determined disease steps (PDDS) scale scores in persons with multiple sclerosis.

    Science.gov (United States)

    Learmonth, Yvonne C; Motl, Robert W; Sandroff, Brian M; Pula, John H; Cadavid, Diego

    2013-04-25

    The Patient Determined Disease Steps (PDDS) is a promising patient-reported outcome (PRO) of disability in multiple sclerosis (MS). To date, there is limited evidence regarding the validity of PDDS scores, despite its sound conceptual development and broad inclusion in MS research. This study examined the validity of the PDDS based on (1) the association with Expanded Disability Status Scale (EDSS) scores and (2) the pattern of associations between PDDS and EDSS scores with Functional System (FS) scores as well as ambulatory and other outcomes. 96 persons with MS provided demographic/clinical information, completed the PDDS and other PROs including the Multiple Sclerosis Walking Scale-12 (MSWS-12), and underwent a neurological examination for generating FS and EDSS scores. Participants completed assessments of cognition, ambulation including the 6-minute walk (6 MW), and wore an accelerometer during waking hours over seven days. There was a strong correlation between EDSS and PDDS scores (ρ = .783). PDDS and EDSS scores were strongly correlated with Pyramidal (ρ = .578 &ρ = .647, respectively) and Cerebellar (ρ = .501 &ρ = .528, respectively) FS scores as well as 6 MW distance (ρ = .704 &ρ = .805, respectively), MSWS-12 scores (ρ = .801 &ρ = .729, respectively), and accelerometer steps/day (ρ = -.740 &ρ = -.717, respectively). This study provides novel evidence supporting the PDDS as valid PRO of disability in MS.

  15. Construct Validity and Reliability Measures of Scores from the Science Teachers' Pedagogical Discontentment (STPD) Scale

    Science.gov (United States)

    Kahveci, Murat; Kahveci, Ajda; Mansour, Nasser; Mohammed, Maher

    2016-01-01

    The Science Teachers' Pedagogical Discontentment (STPD) scale has formerly been developed in the United States and used since 2006. Based on the perceptions of selected teachers, the scale is deeply rooted in the cultural and national standards. Given these limitations, the measurement integrity of its scores has not yet been conclusively…

  16. Exploring Shared Measurement Properties and Score Comparability between Two Versions of the "Supports Intensity Scale"

    Science.gov (United States)

    Seo, Hyojeong; Shogren, Karrie A.; Wehmeyer, Michael L.; Hughes, Carolyn; Thompson, James R.; Little, Todd D.; Palmer, Susan B.

    2016-01-01

    This study examined similarities and differences in measurement properties and score comparability of the "Supports Intensity Scale-Adult Version" (16-64 years) and the "Supports Intensity Scale-Children's Version" (5-16 years). Data were collected from 142 adolescents with intellectual disability with both versions of the…

  17. Decreasing scoring errors on Wechsler Scale Vocabulary, Comprehension, and Similarities subtests: a preliminary study.

    Science.gov (United States)

    Linger, Michele L; Ray, Glen E; Zachar, Peter; Underhill, Andrea T; LoBello, Steven G

    2007-10-01

    Studies of graduate students learning to administer the Wechsler scales have generally shown that training is not associated with the development of scoring proficiency. Many studies report on the reduction of aggregated administration and scoring errors, a strategy that does not highlight the reduction of errors on subtests identified as most prone to error. This study evaluated the development of scoring proficiency specifically on the Wechsler (WISC-IV and WAIS-III) Vocabulary, Comprehension, and Similarities subtests during training by comparing a set of 'early test administrations' to 'later test administrations.' Twelve graduate students enrolled in an intelligence-testing course participated in the study. Scoring errors (e.g., incorrect point assignment) were evaluated on the students' actual practice administration test protocols. Errors on all three subtests declined significantly when scoring errors on 'early' sets of Wechsler scales were compared to those made on 'later' sets. However, correcting these subtest scoring errors did not cause significant changes in subtest scaled scores. Implications for clinical instruction and future research are discussed.

  18. An Analysis of Cross Racial Identity Scale Scores Using Classical Test Theory and Rasch Item Response Models

    Science.gov (United States)

    Sussman, Joshua; Beaujean, A. Alexander; Worrell, Frank C.; Watson, Stevie

    2013-01-01

    Item response models (IRMs) were used to analyze Cross Racial Identity Scale (CRIS) scores. Rasch analysis scores were compared with classical test theory (CTT) scores. The partial credit model demonstrated a high goodness of fit and correlations between Rasch and CTT scores ranged from 0.91 to 0.99. CRIS scores are supported by both methods.…

  19. Reassessing the "traditional background hypothesis" for elevated MMPI and MMPI-2 Lie-scale scores.

    Science.gov (United States)

    Rosen, Gerald M; Baldwin, Scott A; Smith, Ronald E

    2016-10-01

    The Lie (L) scale of the Minnesota Multiphasic Personality Inventory (MMPI) is widely regarded as a measure of conscious attempts to deny common human foibles and to present oneself in an unrealistically positive light. At the same time, the current MMPI-2 manual states that "traditional" and religious backgrounds can account for elevated L scale scores as high as 65T-79T, thereby tempering impression management interpretations for faith-based individuals. To assess the validity of the traditional background hypothesis, we reviewed 11 published studies that employed the original MMPI with religious samples and found that only 1 obtained an elevated mean L score. We then conducted a meta-analysis of 12 published MMPI-2 studies in which we compared L scores of religious samples to the test normative group. The meta-analysis revealed large between-study heterogeneity (I2 = 87.1), L scale scores for religious samples that were somewhat higher but did not approach the upper limits specified in the MMPI-2 manual, and an overall moderate effect size (d¯ = 0.54, p < .001; 95% confidence interval [0.37, 0.70]). Our analyses indicated that religious-group membership accounts, on average, for elevations on L of about 5 t-score points. Whether these scores reflect conscious "fake good" impression management or religious-based virtuousness remains unanswered. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  20. Combined rankine and vapor compression cycles

    Science.gov (United States)

    Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

    2005-04-19

    An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

  1. The Impact of Overreporting on MMPI-2-RF Substantive Scale Score Validity

    Science.gov (United States)

    Burchett, Danielle L.; Ben-Porath, Yossef S.

    2010-01-01

    This study examined the impact of overreporting on the validity of Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) substantive scale scores by comparing correlations with relevant external criteria (i.e., validity coefficients) of individuals who completed the instrument under instructions to (a) feign psychopathology…

  2. Technical Analysis of Scores on the "Self-Efficacy Self-Report Scale"

    Science.gov (United States)

    Erford, Bradley T.; Schein, Hallie; Duncan, Kelly

    2011-01-01

    The purpose of this study was to provide preliminary analysis of reliability and validity of scores on the "Self-Efficacy Self-Report Scale", which was designed to assess general self-efficacy in students aged 10 to 17 years. Confirmatory factor analysis on cross-validated samples was conducted revealing a marginal fit of the data to the…

  3. A Note on the Score Reliability for the Satisfaction with Life Scale: An RG Study

    Science.gov (United States)

    Vassar, Matt

    2008-01-01

    The purpose of the present study was to meta-analytically investigate the score reliability for the Satisfaction With Life Scale. Four-hundred and sixteen articles using the measure were located through electronic database searches and then separated to identify studies which had calculated reliability estimates from their own data. Sixty-two…

  4. Comparison of WAIS-III Short Forms for Measuring Index and Full-Scale Scores

    Science.gov (United States)

    Girard, Todd A.; Axelrod, Bradley N.; Wilkins, Leanne K.

    2010-01-01

    This investigation assessed the ability of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) short forms to estimate both index and IQ scores in a large, mixed clinical sample (N = 809). More specifically, a commonly used modification of Ward's seven-subtest short form (SF7-A), a recently proposed index-based SF7-C and eight-subtest…

  5. [The Collage Impression Scoring Scale (CIISS) may help predict sobriety for alcoholics].

    Science.gov (United States)

    Itoh, Mitsuru; Ishii, Takayoshi

    2009-08-01

    The Collage Impression Scoring Scale (CISS; Imamura, 2004) was used by 54 raters to score collages made by 24 alcoholics on admission to the hospital and at discharge. The CISS contains three factors: stability, expression and creativity. Comparisons using paired t-tests showed that the collages made at discharge had lower scores on the three CISS factors than the collages made on admission. The results for 11 alcoholics, who were followed for six months after discharge, showed that the scores for CISS factors for the abstinent group were lower than those for the relapsed drinking group. The abstinent group showed more anxiety than the relapsed drinking group. This result suggests that the abstinent alcoholics'anxieties were projected onto the collages because they were facing their internal problems more seriously. Thus the CISS was effective as a predictive index for alcoholics who maintain sobriety.

  6. Organic Rankine Cycles. Old wine in new bottles; Organic Rankine Cycles. Oude wijn in nieuwe zakken

    Energy Technology Data Exchange (ETDEWEB)

    Den Hartog, T.L.B. [Cumae, Arnhem (Netherlands)

    2007-05-15

    An overview is given of the renewed interest for the Organic Rankine Cycle technology and new developments with regard to this power generating technology. [Dutch] Een overzicht wordt gegeven van de hernieuwde belangstelling voor de Organic Rankine Cycle (ORC) technologie en nieuwe ontwikkeling m.b.t. deze vorm van elektriciteitopwekking.

  7. Fall risk assessment: retrospective analysis of Morse Fall Scale scores in Portuguese hospitalized adult patients.

    Science.gov (United States)

    Sardo, Pedro Miguel Garcez; Simões, Cláudia Sofia Oliveira; Alvarelhão, José Joaquim Marques; Simões, João Filipe Fernandes Lindo; Melo, Elsa Maria de Oliveira Pinheiro de

    2016-08-01

    The Morse Fall Scale is used in several care settings for fall risk assessment and supports the implementation of preventive nursing interventions. Our work aims to analyze the Morse Fall Scale scores of Portuguese hospitalized adult patients in association with their characteristics, diagnoses and length of stay. Retrospective cohort analysis of Morse Fall Scale scores of 8356 patients hospitalized during 2012. Data were associated to age, gender, type of admission, specialty units, length of stay, patient discharge, and ICD-9 diagnosis. Elderly patients, female, with emergency service admission, at medical units and/or with longer length of stays were more frequently included in the risk group for falls. ICD-9 diagnosis may also be an important risk factor. More than a half of hospitalized patients had "medium" to "high" risk of falling during the length of stay, which determines the implementation and maintenance of protocoled preventive nursing interventions throughout hospitalization. There are several fall risk factors not assessed by Morse Fall Scale. There were no statistical differences in Morse Fall Scale score between the first and the last assessment. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Genetic parameter estimates among scale activity score and farrowing disposition with reproductive traits in swine.

    Science.gov (United States)

    Schneider, J F; Rempel, L A; Rohrer, G A; Brown-Brandl, T M

    2011-11-01

    The primary objective of this study was to determine if certain behavior traits were genetically correlated with reproduction. If 1 or both of the behavior traits were found to be correlated, a secondary objective was to determine if the behavior traits could be useful in selecting for more productive females. A scale activity score taken at 5 mo of age and a farrowing disposition score taken at farrowing were selected as the behavioral traits. Scale activity score ranged from 1 to 5 and farrowing disposition ranged from 1 to 3. Reproductive traits included age at puberty, number born alive, number born dead, litter birth weight, average piglet birth weight, number weaned, litter weaning weight, average weaning weight, wean-to-estrus interval, ovulation rate including gilts, and postweaning ovulation rate. Genetic correlations between scale activity score and reproduction ranged from -0.79 to 0.61. Three of the correlations, number born alive (P < 0.01), average piglet birth weight (P < 0.001), and wean-to-estrus interval (P = 0.014), were statistically significant but included both favorable and antagonistic correlations. In contrast, all but 1 of the farrowing disposition correlations was favorable and ranged from -0.66 to 0.67. Although only the correlation with litter birth weight was significant (P = 0.018), the consistent favorable direction of all farrowing disposition correlations, except average weaning weight, shows a potential for inclusion of farrowing disposition into a selection program.

  9. Graduate Student WAIS-III Scoring Accuracy Is a Function of Full Scale IQ and Complexity of Examiner Tasks

    Science.gov (United States)

    Hopwood, Christopher J.; Richard, David C. S.

    2005-01-01

    Research on the Wechsler Adult Intelligence Scale-Revised and Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) suggests that practicing clinical psychologists and graduate students make item-level scoring errors that affect IQ, index, and subtest scores. Studies have been limited in that Full-Scale IQ (FSIQ) and examiner administration,…

  10. Severity score system for progressive myelopathy: development and validation of a new clinical scale

    Directory of Open Access Journals (Sweden)

    R.M. Castilhos

    2012-07-01

    Full Text Available Progressive myelopathies can be secondary to inborn errors of metabolism (IEM such as mucopolysaccharidosis, mucolipidosis, and adrenomyeloneuropathy. The available scale, Japanese Orthopaedic Association (JOA score, was validated only for degenerative vertebral diseases. Our objective is to propose and validate a new scale addressing progressive myelopathies and to present validating data for JOA in these diseases. A new scale, Severity Score System for Progressive Myelopathy (SSPROM, covering motor disability, sphincter dysfunction, spasticity, and sensory losses. Inter- and intra-rater reliabilities were measured. External validation was tested by applying JOA, the Expanded Disability Status Scale (EDSS, the Barthel index, and the Osame Motor Disability Score. Thirty-eight patients, 17 with adrenomyeloneuropathy, 3 with mucopolysaccharidosis I, 3 with mucopolysaccharidosis IV, 2 with mucopolysaccharidosis VI, 2 with mucolipidosis, and 11 with human T-cell lymphotropic virus type-1 (HTLV-1-associated myelopathy participated in the study. The mean ± SD SSPROM and JOA scores were 74.6 ± 11.4 and 12.4 ± 2.3, respectively. Construct validity for SSPROM (JOA: r = 0.84, P < 0.0001; EDSS: r = -0.83, P < 0.0001; Barthel: r = 0.56, P < 0.002; Osame: r = -0.94, P < 0.0001 and reliability (intra-rater: r = 0.83, P < 0.0001; inter-rater: r = 0.94, P < 0.0001 were demonstrated. The metric properties of JOA were similar to those found in SSPROM. Several clinimetric requirements were met for both SSPROM and JOA scales. Since SSPROM has a wider range, it should be useful for follow-up studies on IEM myelopathies.

  11. Psychometric Properties of the Quantitative Myasthenia Gravis Score and the Myasthenia Gravis Composite Scale.

    Science.gov (United States)

    Barnett, Carolina; Merkies, Ingemar S J; Katzberg, Hans; Bril, Vera

    2015-09-02

    The Quantitative Myasthenia Gravis Score and the Myasthenia Gravis Composite are two commonly used outcome measures in Myasthenia Gravis. So far, their measurement properties have not been compared, so we aimed to study their psychometric properties using the Rasch model. 251 patients with stable myasthenia gravis were assessed with both scales, and 211 patients returned for a second assessment. We studied fit to the Rasch model at the first visit, and compared item fit, thresholds, differential item functioning, local dependence, person separation index, and tests for unidimensionality. We also assessed test-retest reliability and estimated the Minimal Detectable Change. Neither scale fit the Rasch model (X2p Myasthenia Gravis Composite had lower discrimination properties than the Quantitative Myasthenia Gravis Scale (Person Separation Index: 0.14 and 0.7). There was local dependence in both scales, as well as differential item functioning for ocular and generalized disease. Disordered thresholds were found in 6(60%) items of the Myasthenia Gravis Composite and in 4(31%) of the Quantitative Myasthenia Gravis Score. Both tools had adequate test-retest reliability (ICCs >0.8). The minimally detectable change was 4.9 points for the Myasthenia Gravis Composite and 4.3 points for the Quantitative Myasthenia Gravis Score. Neither scale fulfilled Rasch model expectations. The Quantitative Myasthenia Gravis Score has higher discrimination than the Myasthenia Gravis Composite. Both tools have items with disordered thresholds, differential item functioning and local dependency. There was evidence of multidimensionality in the QMGS. The minimal detectable change values are higher than previous studies on the minimal significant change. These findings might inform future modifications of these tools.

  12. Method of administration of PROMIS scales did not significantly impact score level, reliability, or validity

    DEFF Research Database (Denmark)

    Bjorner, Jakob B; Rose, Matthias; Gandek, Barbara

    2014-01-01

    OBJECTIVES: To test the impact of the method of administration (MOA) on score level, reliability, and validity of scales developed in the Patient Reported Outcomes Measurement Information System (PROMIS). STUDY DESIGN AND SETTING: Two nonoverlapping parallel forms each containing eight items from......, no significant mode differences were found and all confidence intervals were within the prespecified minimal important difference of 0.2 standard deviation. Parallel-forms reliabilities were very high (ICC = 0.85-0.93). Only one across-mode ICC was significantly lower than the same-mode ICC. Tests of validity...... questionnaire (PQ), personal digital assistant (PDA), or personal computer (PC) and a second form by PC, in the same administration. Method equivalence was evaluated through analyses of difference scores, intraclass correlations (ICCs), and convergent/discriminant validity. RESULTS: In difference score analyses...

  13. A pediatric FOUR score coma scale: interrater reliability and predictive validity.

    Science.gov (United States)

    Czaikowski, Brianna L; Liang, Hong; Stewart, C Todd

    2014-04-01

    The Full Outline of UnResponsiveness (FOUR) Score is a coma scale that consists of four components (eye and motor response, brainstem reflexes, and respiration). It was originally validated among the adult population and recently in a pediatric population. To enhance clinical assessment of pediatric intensive care unit patients, including those intubated and/or sedated, at our children's hospital, we modified the FOUR Score Scale for this population. This modified scale would provide many of the same advantages as the original, such as interrater reliability, simplicity, and elimination of the verbal component that is not compatible with the Glasgow Coma Scale (GCS), creating a more valuable neurological assessment tool for the nursing community. Our goal was to potentially provide greater information than the formally used GCS when assessing critically ill, neurologically impaired patients, including those sedated and/or intubated. Experienced pediatric intensive care unit nurses were trained as "expert raters." Two different nurses assessed each subject using the Pediatric FOUR Score Scale (PFSS), GCS, and Richmond Agitation Sedation Scale at three different time points. Data were compared with the Pediatric Cerebral Performance Category (PCPC) assessed by another nurse. Our hypothesis was that the PFSS and PCPC should highly correlate and the GCS and PCPC should correlate lower. Study results show that the PFSS is excellent for interrater reliability for trained nurse-rater pairs and prediction of poor outcome and in-hospital mortality, under various situations, but there were no statistically significant differences between the PFSS and the GCS. However, the PFSS does have the potential to provide greater neurological assessment in the intubated and/or sedated patient based on the outcomes of our study.

  14. Relationship between family history of alcohol addiction, parents' education level, and smartphone problem use scale scores.

    Science.gov (United States)

    Beison, Ashley; Rademacher, David J

    2017-03-01

    Background and aims Smartphones are ubiquitous. As smartphones increased in popularity, researchers realized that people were becoming dependent on their smartphones. The purpose here was to provide a better understanding of the factors related to problematic smartphone use (PSPU). Methods The participants were 100 undergraduates (25 males, 75 females) whose ages ranged from 18 to 23 (mean age = 20 years). The participants completed questionnaires to assess gender, ethnicity, year in college, father's education level, mother's education level, family income, age, family history of alcoholism, and PSPU. The Family Tree Questionnaire assessed family history of alcoholism. The Mobile Phone Problem Use Scale (MPPUS) and the Adapted Cell Phone Addiction Test (ACPAT) were used to determine the degree of PSPU. Whereas the MPPUS measures tolerance, escape from other problems, withdrawal, craving, and negative life consequences, the ACPAT measures preoccupation (salience), excessive use, neglecting work, anticipation, lack of control, and neglecting social life. Results Family history of alcoholism and father's education level together explained 26% of the variance in the MPPUS scores and 25% of the variance in the ACPAT scores. The inclusion of mother's education level, ethnicity, family income, age, year in college, and gender did not significantly increase the proportion of variance explained for either MPPUS or ACPAT scores. Discussion and conclusions Family history of alcoholism and father's education level are good predictors of PSPU. As 74%-75% of the variance in PSPU scale scores was not explained, future studies should aim to explain this variance.

  15. Apparently abnormal Wechsler Memory Scale index score patterns in the normal population.

    Science.gov (United States)

    Carrasco, Roman Marcus; Grups, Josefine; Evans, Brittney; Simco, Edward; Mittenberg, Wiley

    2015-01-01

    Interpretation of the Wechsler Memory Scale-Fourth Edition may involve examination of multiple memory index score contrasts and similar comparisons with Wechsler Adult Intelligence Scale-Fourth Edition ability indexes. Standardization sample data suggest that 15-point differences between any specific pair of index scores are relatively uncommon in normal individuals, but these base rates refer to a comparison between a single pair of indexes rather than multiple simultaneous comparisons among indexes. This study provides normative data for the occurrence of multiple index score differences calculated by using Monte Carlo simulations and validated against standardization data. Differences of 15 points between any two memory indexes or between memory and ability indexes occurred in 60% and 48% of the normative sample, respectively. Wechsler index score discrepancies are normally common and therefore not clinically meaningful when numerous such comparisons are made. Explicit prior interpretive hypotheses are necessary to reduce the number of index comparisons and associated false-positive conclusions. Monte Carlo simulation accurately predicts these false-positive rates.

  16. Spacecraft COst REduction Team (SCORE): TQM/CI on a massive scale

    Science.gov (United States)

    Bullard, Jerry D.

    1992-01-01

    The business of building satellites and space systems has matured. Few missions require, or can afford, excellent performance at any price. The new paradigm is doing more with less, providing quality systems at lower cost--in other words, doing our job 'Faster-Better-Cheaper.' The TRW Spacecraft COst REduction (SCORE) initiative was launched in 1990 by Daniel S. Goldin, then general manager of TRW's Space & Technology Group. The SCORE mission is to apply continuous improvement (CI) techniques to effect major reductions in the cost (our primary goal) and span time (as a corollary) required for the production of spacecraft. SCORE is a multi-year initiative that is having a profound effect on both the procedural and the cultural aspects of how we do business. The objectives of this initiative are being realized. The focus of this paper is not on the results of SCORE per se, but rather on the things we have leaned about how to do continuous improvement on a massive scale, with multilevel (hierarchical) CI teams. The following sections summarize the chronology of the SCORE initiative, from team formation to development of the year-end report for 1991. Lessons learned, the core of this presentation, are discussed--with particular focus on the unique aspects of SCORE. The SCORE initiative is continuing and, as a part of our evolving culture, will never end. It has resulted in profound insights into the way we do work and (the topic at hand) how to do CI for large and complex multidisciplinary development activities.

  17. Turbomachinery design for Rankine cycles in waste heat recovery applications

    OpenAIRE

    Agromayor Otero, Roberto

    2017-01-01

    Rankine Cycles are an effective and efficient manner to convert waste thermal energy into power. Numerous fluids can be used in Rankine cycles, including water, hydrocarbons, hydrofluorocarbons, siloxanes, alcohols or even mixtures of fluids. The performance of Rankine cycles is highly dependent on the optimization of the operating conditions and the design of its components. The expander is, perhaps, the most important component of the Rankine cycle, as it is the device where the energy of t...

  18. Assessing coral reefs on a Pacific-wide scale using the microbialization score.

    Directory of Open Access Journals (Sweden)

    Tracey McDole

    Full Text Available The majority of the world's coral reefs are in various stages of decline. While a suite of disturbances (overfishing, eutrophication, and global climate change have been identified, the mechanism(s of reef system decline remain elusive. Increased microbial and viral loading with higher percentages of opportunistic and specific microbial pathogens have been identified as potentially unifying features of coral reefs in decline. Due to their relative size and high per cell activity, a small change in microbial biomass may signal a large reallocation of available energy in an ecosystem; that is the microbialization of the coral reef. Our hypothesis was that human activities alter the energy budget of the reef system, specifically by altering the allocation of metabolic energy between microbes and macrobes. To determine if this is occurring on a regional scale, we calculated the basal metabolic rates for the fish and microbial communities at 99 sites on twenty-nine coral islands throughout the Pacific Ocean using previously established scaling relationships. From these metabolic rate predictions, we derived a new metric for assessing and comparing reef health called the microbialization score. The microbialization score represents the percentage of the combined fish and microbial predicted metabolic rate that is microbial. Our results demonstrate a strong positive correlation between reef microbialization scores and human impact. In contrast, microbialization scores did not significantly correlate with ocean net primary production, local chla concentrations, or the combined metabolic rate of the fish and microbial communities. These findings support the hypothesis that human activities are shifting energy to the microbes, at the expense of the macrobes. Regardless of oceanographic context, the microbialization score is a powerful metric for assessing the level of human impact a reef system is experiencing.

  19. Assessing coral reefs on a Pacific-wide scale using the microbialization score.

    Science.gov (United States)

    McDole, Tracey; Nulton, James; Barott, Katie L; Felts, Ben; Hand, Carol; Hatay, Mark; Lee, Hochul; Nadon, Marc O; Nosrat, Bahador; Salamon, Peter; Bailey, Barbara; Sandin, Stuart A; Vargas-Angel, Bernardo; Youle, Merry; Zgliczynski, Brian J; Brainard, Russell E; Rohwer, Forest

    2012-01-01

    The majority of the world's coral reefs are in various stages of decline. While a suite of disturbances (overfishing, eutrophication, and global climate change) have been identified, the mechanism(s) of reef system decline remain elusive. Increased microbial and viral loading with higher percentages of opportunistic and specific microbial pathogens have been identified as potentially unifying features of coral reefs in decline. Due to their relative size and high per cell activity, a small change in microbial biomass may signal a large reallocation of available energy in an ecosystem; that is the microbialization of the coral reef. Our hypothesis was that human activities alter the energy budget of the reef system, specifically by altering the allocation of metabolic energy between microbes and macrobes. To determine if this is occurring on a regional scale, we calculated the basal metabolic rates for the fish and microbial communities at 99 sites on twenty-nine coral islands throughout the Pacific Ocean using previously established scaling relationships. From these metabolic rate predictions, we derived a new metric for assessing and comparing reef health called the microbialization score. The microbialization score represents the percentage of the combined fish and microbial predicted metabolic rate that is microbial. Our results demonstrate a strong positive correlation between reef microbialization scores and human impact. In contrast, microbialization scores did not significantly correlate with ocean net primary production, local chla concentrations, or the combined metabolic rate of the fish and microbial communities. These findings support the hypothesis that human activities are shifting energy to the microbes, at the expense of the macrobes. Regardless of oceanographic context, the microbialization score is a powerful metric for assessing the level of human impact a reef system is experiencing.

  20. Defining the minimal detectable change in scores on the eight-item Morisky Medication Adherence Scale.

    Science.gov (United States)

    Muntner, Paul; Joyce, Cara; Holt, Elizabeth; He, Jiang; Morisky, Donald; Webber, Larry S; Krousel-Wood, Marie

    2011-05-01

    Self-report scales are used to assess medication adherence. Data on how to discriminate change in self-reported adherence over time from random variability are limited. To determine the minimal detectable change for scores on the 8-item Morisky Medication Adherence Scale (MMAS-8). The MMAS-8 was administered twice, using a standard telephone script, with administration separated by 14-22 days, to 210 participants taking antihypertensive medication in the CoSMO (Cohort Study of Medication Adherence among Older Adults). MMAS-8 scores were calculated and participants were grouped into previously defined categories (<6, 6 to <8, and 8 for low, medium, and high adherence). The mean (SD) age of participants was 78.1 (5.8) years, 43.8% were black, and 68.1% were women. Overall, 8.1% (17/210), 16.2% (34/210), and 51.0% (107/210) of participants had low, medium, and high MMAS-8 scores, respectively, at both survey administrations (overall agreement 75.2%; 158/210). The weighted κ statistic was 0.63 (95% CI 0.53 to 0.72). The intraclass correlation coefficient was 0.78. The within-person standard error of the mean for change in MMAS-8 scores was 0.81, which equated to a minimal detectable change of 1.98 points. Only 4.3% (9/210) of the participants had a change in MMAS-8 of 2 or more points between survey administrations. Within-person changes in MMAS-8 scores of 2 or more points over time may represent a real change in antihypertensive medication adherence.

  1. Association of metabolic syndrome and change in Unified Parkinson's Disease Rating Scale scores.

    Science.gov (United States)

    Leehey, Maureen; Luo, Sheng; Sharma, Saloni; Wills, Anne-Marie A; Bainbridge, Jacquelyn L; Wong, Pei Shieen; Simon, David K; Schneider, Jay; Zhang, Yunxi; Pérez, Adriana; Dhall, Rohit; Christine, Chadwick W; Singer, Carlos; Cambi, Franca; Boyd, James T

    2017-10-24

    To explore the association between metabolic syndrome and the Unified Parkinson's Disease Rating Scale (UPDRS) scores and, secondarily, the Symbol Digit Modalities Test (SDMT). This is a secondary analysis of data from 1,022 of 1,741 participants of the National Institute of Neurological Disorders and Stroke Exploratory Clinical Trials in Parkinson Disease Long-Term Study 1, a randomized, placebo-controlled trial of creatine. Participants were categorized as having or not having metabolic syndrome on the basis of modified criteria from the National Cholesterol Education Program Adult Treatment Panel III. Those who had the same metabolic syndrome status at consecutive annual visits were included. The change in UPDRS and SDMT scores from randomization to 3 years was compared in participants with and without metabolic syndrome. Participants with metabolic syndrome (n = 396) compared to those without (n = 626) were older (mean [SD] 63.9 [8.1] vs 59.9 [9.4] years; p metabolic syndrome experienced an additional 0.6- (0.2) unit annual increase in total UPDRS ( p = 0.02) and 0.5- (0.2) unit increase in motor UPDRS ( p = 0.01) scores compared with participants without metabolic syndrome. There was no difference in the change in SDMT scores. Persons with Parkinson disease meeting modified criteria for metabolic syndrome experienced a greater increase in total UPDRS scores over time, mainly as a result of increases in motor scores, compared to those who did not. Further studies are needed to confirm this finding. NCT00449865. © 2017 American Academy of Neurology.

  2. Modified Ashworth scale and spasm frequency score in spinal cord injury

    DEFF Research Database (Denmark)

    Baunsgaard, C. B.; Nissen, U. V.; Christensen, K. B.

    2016-01-01

    .94 and inter-rater κweighted=0.93. Correlation between MAS and SFS showed non-significant correlation coefficients from-0.11 to 0.90. CONCLUSION: Reliability of MAS is highly affected by the weighting scheme. With a weighted-κ it was overall reliable and simple-κ overall unreliability. Repeated tests should......STUDY DESIGN: Intra- and inter-rater reliability study. OBJECTIVES: To assess intra- and inter-rater reliability of the Modified Ashworth Scale (MAS) and Spasm Frequency Score (SFS) in lower extremities in a population of spinal cord-injured persons, as well as correlations between the two scales....... SETTING: Clinic for Spinal Cord Injuries, Rigshospitalet, Hornbaek, Denmark. METHODS: Thirty-one persons participated in the study and were tested four times in total with MAS and SFS by three experienced raters. Cohen's kappa (κ), simple and quadratic weighted (nominal and ordinal scale level...

  3. Reliability and validity of the new Tanaka B Intelligence Scale scores: a group intelligence test.

    Directory of Open Access Journals (Sweden)

    Yota Uno

    Full Text Available OBJECTIVE: The present study evaluated the reliability and concurrent validity of the new Tanaka B Intelligence Scale, which is an intelligence test that can be administered on groups within a short period of time. METHODS: The new Tanaka B Intelligence Scale and Wechsler Intelligence Scale for Children-Third Edition were administered to 81 subjects (mean age ± SD 15.2 ± 0.7 years residing in a juvenile detention home; reliability was assessed using Cronbach's alpha coefficient, and concurrent validity was assessed using the one-way analysis of variance intraclass correlation coefficient. Moreover, receiver operating characteristic analysis for screening for individuals who have a deficit in intellectual function (an FIQ<70 was performed. In addition, stratum-specific likelihood ratios for detection of intellectual disability were calculated. RESULTS: The Cronbach's alpha for the new Tanaka B Intelligence Scale IQ (BIQ was 0.86, and the intraclass correlation coefficient with FIQ was 0.83. Receiver operating characteristic analysis demonstrated an area under the curve of 0.89 (95% CI: 0.85-0.96. In addition, the stratum-specific likelihood ratio for the BIQ≤65 stratum was 13.8 (95% CI: 3.9-48.9, and the stratum-specific likelihood ratio for the BIQ≥76 stratum was 0.1 (95% CI: 0.03-0.4. Thus, intellectual disability could be ruled out or determined. CONCLUSION: The present results demonstrated that the new Tanaka B Intelligence Scale score had high reliability and concurrent validity with the Wechsler Intelligence Scale for Children-Third Edition score. Moreover, the post-test probability for the BIQ could be calculated when screening for individuals who have a deficit in intellectual function. The new Tanaka B Intelligence Test is convenient and can be administered within a variety of settings. This enables evaluation of intellectual development even in settings where performing intelligence tests have previously been difficult.

  4. Reliability and validity of the new Tanaka B Intelligence Scale scores: a group intelligence test.

    Science.gov (United States)

    Uno, Yota; Mizukami, Hitomi; Ando, Masahiko; Yukihiro, Ryoji; Iwasaki, Yoko; Ozaki, Norio

    2014-01-01

    The present study evaluated the reliability and concurrent validity of the new Tanaka B Intelligence Scale, which is an intelligence test that can be administered on groups within a short period of time. The new Tanaka B Intelligence Scale and Wechsler Intelligence Scale for Children-Third Edition were administered to 81 subjects (mean age ± SD 15.2 ± 0.7 years) residing in a juvenile detention home; reliability was assessed using Cronbach's alpha coefficient, and concurrent validity was assessed using the one-way analysis of variance intraclass correlation coefficient. Moreover, receiver operating characteristic analysis for screening for individuals who have a deficit in intellectual function (an FIQIntelligence Scale IQ (BIQ) was 0.86, and the intraclass correlation coefficient with FIQ was 0.83. Receiver operating characteristic analysis demonstrated an area under the curve of 0.89 (95% CI: 0.85-0.96). In addition, the stratum-specific likelihood ratio for the BIQ≤65 stratum was 13.8 (95% CI: 3.9-48.9), and the stratum-specific likelihood ratio for the BIQ≥76 stratum was 0.1 (95% CI: 0.03-0.4). Thus, intellectual disability could be ruled out or determined. The present results demonstrated that the new Tanaka B Intelligence Scale score had high reliability and concurrent validity with the Wechsler Intelligence Scale for Children-Third Edition score. Moreover, the post-test probability for the BIQ could be calculated when screening for individuals who have a deficit in intellectual function. The new Tanaka B Intelligence Test is convenient and can be administered within a variety of settings. This enables evaluation of intellectual development even in settings where performing intelligence tests have previously been difficult.

  5. Gait and Glasgow Coma Scale scores can predict functional recovery in patients with traumatic brain injury☆

    Science.gov (United States)

    Bilgin, Sevil; Guclu-Gunduz, Arzu; Oruckaptan, Hakan; Kose, Nezire; Celik, Bülent

    2012-01-01

    Fifty-one patients with mild (n = 14), moderate (n = 10) and severe traumatic brain injury (n = 27) received early rehabilitation. Level of consciousness was evaluated using the Glasgow Coma Score. Functional level was determined using the Glasgow Outcome Score, whilst mobility was evaluated using the Mobility Scale for Acute Stroke. Activities of daily living were assessed using the Barthel Index. Following Bobath neurodevelopmental therapy, the level of consciousness was significantly improved in patients with moderate and severe traumatic brain injury, but was not greatly influenced in patients with mild traumatic brain injury. Mobility and functional level were significantly improved in patients with mild, moderate and severe traumatic brain injury. Gait recovery was more obvious in patients with mild traumatic brain injury than in patients with moderate and severe traumatic brain injury. Activities of daily living showed an improvement but this was insignificant except for patients with severe traumatic brain injury. Nevertheless, complete recovery was not acquired at discharge. Multiple regression analysis showed that gait and Glasgow Coma Scale scores can be considered predictors of functional outcomes following traumatic brain injury. PMID:25624828

  6. Substantial improvements in large-scale redocking and screening using the novel HYDE scoring function

    Science.gov (United States)

    Schneider, Nadine; Hindle, Sally; Lange, Gudrun; Klein, Robert; Albrecht, Jürgen; Briem, Hans; Beyer, Kristin; Claußen, Holger; Gastreich, Marcus; Lemmen, Christian; Rarey, Matthias

    2012-06-01

    The HYDE scoring function consistently describes hydrogen bonding, the hydrophobic effect and desolvation. It relies on HYdration and DEsolvation terms which are calibrated using octanol/water partition coefficients of small molecules. We do not use affinity data for calibration, therefore HYDE is generally applicable to all protein targets. HYDE reflects the Gibbs free energy of binding while only considering the essential interactions of protein-ligand complexes. The greatest benefit of HYDE is that it yields a very intuitive atom-based score, which can be mapped onto the ligand and protein atoms. This allows the direct visualization of the score and consequently facilitates analysis of protein-ligand complexes during the lead optimization process. In this study, we validated our new scoring function by applying it in large-scale docking experiments. We could successfully predict the correct binding mode in 93% of complexes in redocking calculations on the Astex diverse set, while our performance in virtual screening experiments using the DUD dataset showed significant enrichment values with a mean AUC of 0.77 across all protein targets with little or no structural defects. As part of these studies, we also carried out a very detailed analysis of the data that revealed interesting pitfalls, which we highlight here and which should be addressed in future benchmark datasets.

  7. Empirical Correlates of Low Scores on MMPI-2/MMPI-2-RF Restructured Clinical Scales in a Sample of University Students

    Science.gov (United States)

    Avdeyeva, Tatyana V.; Tellegen, Auke; Ben-Porath, Yossef S.

    2012-01-01

    In the present study, the authors explored the meaning of low scores on the MMPI-2/MMPI-2-RF Restructured Clinical (RC) scales. Using responses of a sample of university students (N = 811), the authors examined whether low (T less than 39), within-normal-limits (T = 39-64), and high (T greater than 65) score levels on the RC scales are…

  8. Rankine cycle waste heat recovery system

    Science.gov (United States)

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-08-12

    This disclosure relates to a waste heat recovery (WHR) system and to a system and method for regulation of a fluid inventory in a condenser and a receiver of a Rankine cycle WHR system. Such regulation includes the ability to regulate the pressure in a WHR system to control cavitation and energy conversion.

  9. Does Wechsler Intelligence Scale administration and scoring proficiency improve during assessment training?

    Science.gov (United States)

    Platt, Tyson L; Zachar, Peter; Ray, Glen E; Lobello, Steven G; Underhill, Andrea T

    2007-04-01

    Studies have found that Wechsler scale administration and scoring proficiency is not easily attained during graduate training. These findings may be related to methodological issues. Using a single-group repeated measures design, this study documents statistically significant, though modest, error reduction on the WAIS-III and WISC-III during a graduate course in assessment. The study design does not permit the isolation of training factors related to error reduction, or assessment of whether error reduction is a function of mere practice. However, the results do indicate that previous study findings of no or inconsistent improvement in scoring proficiency may have been the result of methodological factors. Implications for teaching individual intelligence testing and further research are discussed.

  10. Optimal design of compact organic Rankine cycle units for domestic solar applications

    DEFF Research Database (Denmark)

    Barbazza, Luca; Pierobon, Leonardo; Mirandola, Alberto

    2014-01-01

    criteria, i.e., compactness, high performance and safe operation, are targeted by adopting a multi-objective optimization approach modeled with the genetic algorithm. Design-point thermodynamic variables, e.g., evaporating pressure, the working fluid, minimum allowable temperature differences......Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design...

  11. Relationship between family history of alcohol addiction, parents’ education level, and smartphone problem use scale scores

    Science.gov (United States)

    Beison, Ashley; Rademacher, David J.

    2017-01-01

    Background and aims Smartphones are ubiquitous. As smartphones increased in popularity, researchers realized that people were becoming dependent on their smartphones. The purpose here was to provide a better understanding of the factors related to problematic smartphone use (PSPU). Methods The participants were 100 undergraduates (25 males, 75 females) whose ages ranged from 18 to 23 (mean age = 20 years). The participants completed questionnaires to assess gender, ethnicity, year in college, father’s education level, mother’s education level, family income, age, family history of alcoholism, and PSPU. The Family Tree Questionnaire assessed family history of alcoholism. The Mobile Phone Problem Use Scale (MPPUS) and the Adapted Cell Phone Addiction Test (ACPAT) were used to determine the degree of PSPU. Whereas the MPPUS measures tolerance, escape from other problems, withdrawal, craving, and negative life consequences, the ACPAT measures preoccupation (salience), excessive use, neglecting work, anticipation, lack of control, and neglecting social life. Results Family history of alcoholism and father’s education level together explained 26% of the variance in the MPPUS scores and 25% of the variance in the ACPAT scores. The inclusion of mother’s education level, ethnicity, family income, age, year in college, and gender did not significantly increase the proportion of variance explained for either MPPUS or ACPAT scores. Discussion and conclusions Family history of alcoholism and father’s education level are good predictors of PSPU. As 74%–75% of the variance in PSPU scale scores was not explained, future studies should aim to explain this variance. PMID:28316252

  12. Validation of the DRAGON score in 12 stroke centers in anterior and posterior circulation.

    Science.gov (United States)

    Strbian, Daniel; Seiffge, David J; Breuer, Lorenz; Numminen, Heikki; Michel, Patrik; Meretoja, Atte; Coote, Skye; Bordet, Régis; Obach, Victor; Weder, Bruno; Jung, Simon; Caso, Valeria; Curtze, Sami; Ollikainen, Jyrki; Lyrer, Philippe A; Eskandari, Ashraf; Mattle, Heinrich P; Chamorro, Angel; Leys, Didier; Bladin, Christopher; Davis, Stephen M; Köhrmann, Martin; Engelter, Stefan T; Tatlisumak, Turgut

    2013-10-01

    The DRAGON score predicts functional outcome in the hyperacute phase of intravenous thrombolysis treatment of ischemic stroke patients. We aimed to validate the score in a large multicenter cohort in anterior and posterior circulation. Prospectively collected data of consecutive ischemic stroke patients who received intravenous thrombolysis in 12 stroke centers were merged (n=5471). We excluded patients lacking data necessary to calculate the score and patients with missing 3-month modified Rankin scale scores. The final cohort comprised 4519 eligible patients. We assessed the performance of the DRAGON score with area under the receiver operating characteristic curve in the whole cohort for both good (modified Rankin scale score, 0-2) and miserable (modified Rankin scale score, 5-6) outcomes. Area under the receiver operating characteristic curve was 0.84 (0.82-0.85) for miserable outcome and 0.82 (0.80-0.83) for good outcome. Proportions of patients with good outcome were 96%, 93%, 78%, and 0% for 0 to 1, 2, 3, and 8 to 10 score points, respectively. Proportions of patients with miserable outcome were 0%, 2%, 4%, 89%, and 97% for 0 to 1, 2, 3, 8, and 9 to 10 points, respectively. When tested separately for anterior and posterior circulation, there was no difference in performance (P=0.55); areas under the receiver operating characteristic curve were 0.84 (0.83-0.86) and 0.82 (0.78-0.87), respectively. No sex-related difference in performance was observed (P=0.25). The DRAGON score showed very good performance in the large merged cohort in both anterior and posterior circulation strokes. The DRAGON score provides rapid estimation of patient prognosis and supports clinical decision-making in the hyperacute phase of stroke care (eg, when invasive add-on strategies are considered).

  13. Outcome After Radiosurgery for Brain Metastases in Patients With Low Karnofsky Performance Scale (KPS) Scores

    International Nuclear Information System (INIS)

    Chernov, Mikhail F.; Nakaya, Kotaro; Izawa, Masahiro; Hayashi, Motohiro; Usuba, Yuki; Kato, Koichi; Muragaki, Yoshihiro; Iseki, Hiroshi; Hori, Tomokatsu; Takakura, Kintomo

    2007-01-01

    Purpose: The objective of this retrospective study was evaluation of the outcome after stereotactic radiosurgery (SRS) in patients with intracranial metastases and poor performance status. Methods and Materials: Forty consecutive patients with metastatic brain tumors and Karnofsky performance scale (KPS) scores ≤50 (mean, 43 ± 8; median, 40) treated with SRS were analyzed. Poor performance status was caused by presence of intracranial metastases in 28 cases (70%) and resulted from uncontrolled extracerebral disease in 12 (30%). Results: Survival after SRS varied from 3 days to 11.5 months (mean, 3.8 ± 2.9 months; median, 3.3 months). Survival probability constituted 0.50 ± 0.07 at 3 months and 0.20 ± 0.05 at 6 months posttreatment. Cause of low KPS score (p = 0.0173) and presence of distant metastases beside the brain (p = 0.0308) showed statistically significant associations with overall survival in multivariate Cox proportional hazards regression analysis. Median survival was 6.0 months if low KPS score was caused by cerebral disease and distant metastases in regions beyond the brain were absent, 3.3 months if low KPS score was caused by cerebral disease and distant metastases in regions beyond the brain were present, and 1.0 month if poor performance status resulted from extracerebral disease. Conclusions: Identification of the cause of low KPS score (cerebral vs. extracerebral) in patients with metastatic brain tumor(s) may be important for prediction of the outcome after radiosurgical treatment. If poor patient performance status without surgical indications is caused by intracranial tumor(s), SRS may be a reasonable treatment option

  14. Cascaded organic rankine cycles for waste heat utilization

    Science.gov (United States)

    Radcliff, Thomas D [Vernon, CT; Biederman, Bruce P [West Hartford, CT; Brasz, Joost J [Fayetteville, NY

    2011-05-17

    A pair of organic Rankine cycle systems (20, 25) are combined and their respective organic working fluids are chosen such that the organic working fluid of the first organic Rankine cycle is condensed at a condensation temperature that is well above the boiling point of the organic working fluid of the second organic Rankine style system, and a single common heat exchanger (23) is used for both the condenser of the first organic Rankine cycle system and the evaporator of the second organic Rankine cycle system. A preferred organic working fluid of the first system is toluene and that of the second organic working fluid is R245fa.

  15. High Agreement was Obtained Across Scores from Multiple Equated Scales for Social Anxiety Disorder using Item Response Theory.

    Science.gov (United States)

    Sunderland, Matthew; Batterham, Philip; Calear, Alison; Carragher, Natacha; Baillie, Andrew; Slade, Tim

    2018-04-10

    There is no standardized approach to the measurement of social anxiety. Researchers and clinicians are faced with numerous self-report scales with varying strengths, weaknesses, and psychometric properties. The lack of standardization makes it difficult to compare scores across populations that utilise different scales. Item response theory offers one solution to this problem via equating different scales using an anchor scale to set a standardized metric. This study is the first to equate several scales for social anxiety disorder. Data from two samples (n=3,175 and n=1,052), recruited from the Australian community using online advertisements, were utilised to equate a network of 11 self-report social anxiety scales via a fixed parameter item calibration method. Comparisons between actual and equated scores for most of the scales indicted a high level of agreement with mean differences <0.10 (equivalent to a mean difference of less than one point on the standardized metric). This study demonstrates that scores from multiple scales that measure social anxiety can be converted to a common scale. Re-scoring observed scores to a common scale provides opportunities to combine research from multiple studies and ultimately better assess social anxiety in treatment and research settings. Copyright © 2018. Published by Elsevier Inc.

  16. Hematoma shape, hematoma size, Glasgow coma scale score and ICH score: which predicts the 30-day mortality better for intracerebral hematoma?

    Directory of Open Access Journals (Sweden)

    Chih-Wei Wang

    Full Text Available To investigate the performance of hematoma shape, hematoma size, Glasgow coma scale (GCS score, and intracerebral hematoma (ICH score in predicting the 30-day mortality for ICH patients. To examine the influence of the estimation error of hematoma size on the prediction of 30-day mortality.This retrospective study, approved by a local institutional review board with written informed consent waived, recruited 106 patients diagnosed as ICH by non-enhanced computed tomography study. The hemorrhagic shape, hematoma size measured by computer-assisted volumetric analysis (CAVA and estimated by ABC/2 formula, ICH score and GCS score was examined. The predicting performance of 30-day mortality of the aforementioned variables was evaluated. Statistical analysis was performed using Kolmogorov-Smirnov tests, paired t test, nonparametric test, linear regression analysis, and binary logistic regression. The receiver operating characteristics curves were plotted and areas under curve (AUC were calculated for 30-day mortality. A P value less than 0.05 was considered as statistically significant.The overall 30-day mortality rate was 15.1% of ICH patients. The hematoma shape, hematoma size, ICH score, and GCS score all significantly predict the 30-day mortality for ICH patients, with an AUC of 0.692 (P = 0.0018, 0.715 (P = 0.0008 (by ABC/2 to 0.738 (P = 0.0002 (by CAVA, 0.877 (P<0.0001 (by ABC/2 to 0.882 (P<0.0001 (by CAVA, and 0.912 (P<0.0001, respectively.Our study shows that hematoma shape, hematoma size, ICH scores and GCS score all significantly predict the 30-day mortality in an increasing order of AUC. The effect of overestimation of hematoma size by ABC/2 formula in predicting the 30-day mortality could be remedied by using ICH score.

  17. Hematoma Shape, Hematoma Size, Glasgow Coma Scale Score and ICH Score: Which Predicts the 30-Day Mortality Better for Intracerebral Hematoma?

    Science.gov (United States)

    Wang, Chih-Wei; Liu, Yi-Jui; Lee, Yi-Hsiung; Hueng, Dueng-Yuan; Fan, Hueng-Chuen; Yang, Fu-Chi; Hsueh, Chun-Jen; Kao, Hung-Wen; Juan, Chun-Jung; Hsu, Hsian-He

    2014-01-01

    Purpose To investigate the performance of hematoma shape, hematoma size, Glasgow coma scale (GCS) score, and intracerebral hematoma (ICH) score in predicting the 30-day mortality for ICH patients. To examine the influence of the estimation error of hematoma size on the prediction of 30-day mortality. Materials and Methods This retrospective study, approved by a local institutional review board with written informed consent waived, recruited 106 patients diagnosed as ICH by non-enhanced computed tomography study. The hemorrhagic shape, hematoma size measured by computer-assisted volumetric analysis (CAVA) and estimated by ABC/2 formula, ICH score and GCS score was examined. The predicting performance of 30-day mortality of the aforementioned variables was evaluated. Statistical analysis was performed using Kolmogorov-Smirnov tests, paired t test, nonparametric test, linear regression analysis, and binary logistic regression. The receiver operating characteristics curves were plotted and areas under curve (AUC) were calculated for 30-day mortality. A P value less than 0.05 was considered as statistically significant. Results The overall 30-day mortality rate was 15.1% of ICH patients. The hematoma shape, hematoma size, ICH score, and GCS score all significantly predict the 30-day mortality for ICH patients, with an AUC of 0.692 (P = 0.0018), 0.715 (P = 0.0008) (by ABC/2) to 0.738 (P = 0.0002) (by CAVA), 0.877 (Phematoma shape, hematoma size, ICH scores and GCS score all significantly predict the 30-day mortality in an increasing order of AUC. The effect of overestimation of hematoma size by ABC/2 formula in predicting the 30-day mortality could be remedied by using ICH score. PMID:25029592

  18. Image subsampling and point scoring approaches for large-scale marine benthic monitoring programs

    Science.gov (United States)

    Perkins, Nicholas R.; Foster, Scott D.; Hill, Nicole A.; Barrett, Neville S.

    2016-07-01

    Benthic imagery is an effective tool for quantitative description of ecologically and economically important benthic habitats and biota. The recent development of autonomous underwater vehicles (AUVs) allows surveying of spatial scales that were previously unfeasible. However, an AUV collects a large number of images, the scoring of which is time and labour intensive. There is a need to optimise the way that subsamples of imagery are chosen and scored to gain meaningful inferences for ecological monitoring studies. We examine the trade-off between the number of images selected within transects and the number of random points scored within images on the percent cover of target biota, the typical output of such monitoring programs. We also investigate the efficacy of various image selection approaches, such as systematic or random, on the bias and precision of cover estimates. We use simulated biotas that have varying size, abundance and distributional patterns. We find that a relatively small sampling effort is required to minimise bias. An increased precision for groups that are likely to be the focus of monitoring programs is best gained through increasing the number of images sampled rather than the number of points scored within images. For rare species, sampling using point count approaches is unlikely to provide sufficient precision, and alternative sampling approaches may need to be employed. The approach by which images are selected (simple random sampling, regularly spaced etc.) had no discernible effect on mean and variance estimates, regardless of the distributional pattern of biota. Field validation of our findings is provided through Monte Carlo resampling analysis of a previously scored benthic survey from temperate waters. We show that point count sampling approaches are capable of providing relatively precise cover estimates for candidate groups that are not overly rare. The amount of sampling required, in terms of both the number of images and

  19. The use of test scores from large-scale assessment surveys: psychometric and statistical considerations

    Directory of Open Access Journals (Sweden)

    Henry Braun

    2017-11-01

    Full Text Available Abstract Background Economists are making increasing use of measures of student achievement obtained through large-scale survey assessments such as NAEP, TIMSS, and PISA. The construction of these measures, employing plausible value (PV methodology, is quite different from that of the more familiar test scores associated with assessments such as the SAT or ACT. These differences have important implications both for utilization and interpretation. Although much has been written about PVs, it appears that there are still misconceptions about whether and how to employ them in secondary analyses. Methods We address a range of technical issues, including those raised in a recent article that was written to inform economists using these databases. First, an extensive review of the relevant literature was conducted, with particular attention to key publications that describe the derivation and psychometric characteristics of such achievement measures. Second, a simulation study was carried out to compare the statistical properties of estimates based on the use of PVs with those based on other, commonly used methods. Results It is shown, through both theoretical analysis and simulation, that under fairly general conditions appropriate use of PV yields approximately unbiased estimates of model parameters in regression analyses of large scale survey data. The superiority of the PV methodology is particularly evident when measures of student achievement are employed as explanatory variables. Conclusions The PV methodology used to report student test performance in large scale surveys remains the state-of-the-art for secondary analyses of these databases.

  20. Process integration of organic Rankine cycle

    International Nuclear Information System (INIS)

    Desai, Nishith B.; Bandyopadhyay, Santanu

    2009-01-01

    An organic Rankine cycle (ORC) uses an organic fluid as a working medium within a Rankine cycle power plant. ORC offers advantages over conventional Rankine cycle with water as the working medium, as ORC generates shaft-work from low to medium temperature heat sources with higher thermodynamic efficiency. The dry and the isentropic fluids are most preferred working fluid for the ORC. The basic ORC can be modified by incorporating both regeneration and turbine bleeding to improve its thermal efficiency. In this paper, 16 different organic fluids have been analyzed as a working medium for the basic as well as modified ORCs. A methodology is also proposed for appropriate integration and optimization of an ORC as a cogeneration process with the background process to generate shaft-work. It has been illustrated that the choice of cycle configuration for appropriate integration with the background process depends on the heat rejection profile of the background process (i.e., the shape of the below pinch portion of the process grand composite curve). The benefits of integrating ORC with the background process and the applicability of the proposed methodology have been demonstrated through illustrative examples.

  1. Comparability of scores on the MMPI-2-RF scales generated with the MMPI-2 and MMPI-2-RF booklets.

    Science.gov (United States)

    Van der Heijden, P T; Egger, J I M; Derksen, J J L

    2010-05-01

    In most validity studies on the recently released 338-item MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008; Tellegen & Ben-Porath, 2008), scale scores were derived from the 567-item MMPI-2 booklet. In this study, we evaluated the comparability of the MMPI-2-RF scale scores derived from the original 567-item MMPI-2 booklet with MMPI-2-RF scale scores derived from the 338-item MMPI-2-RF booklet in a Dutch student sample (N = 107). We used a counterbalanced (ABBA) design. We compared results with those previously reported by Tellegen and Ben-Porath (2008). Our findings support the comparability of the scores of the 338-item version and the 567-item version of the 50 MMPI-2-RF scales. We discuss clinical implications and directions for further research.

  2. Recall of false memories in individuals scoring high in schizotypy: memory distortions are scale specific.

    Science.gov (United States)

    Saunders, Jo; Randell, Jordan; Reed, Phil

    2012-06-01

    Previous research has indicated abnormal semantic activation in individuals scoring higher in schizotypy. In the current experiment, semantic activation was examined by using the Deese-Roediger-McDermott paradigm of false memories. Participants were assessed for schizotypy using the Oxford-Liverpool Inventory of Feelings (OLIFE). Participants studied lists of semantically related words in which a critical and highly associated word was absent. Participants then recalled the list. Participants high in Unusual Experiences and Cognitive Disorganization recalled more critical non-presented words, weakly related studied words, and fewer studied words than participants who scored low on these measures. Previous research using the cognitive-perceptual factor of the Schizotypy Personality Questionnaire found reduced false memories, while the Unusual Experiences subscale of the OLIFE was associated with more false memories. Both scales cover similar unusual perceptual experiences and it is unclear why they led to divergent results. The findings suggest that subtypes of schizotypy are associated with abnormal semantic activation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Late effects of normal tissues (lent) scoring system: the soma scale

    International Nuclear Information System (INIS)

    Mornex, F.; Pavy, J.J.; Denekamp, J.

    1997-01-01

    Radiation tolerance of normal tissues remains the limiting factor for delivering tumoricidal dose. The late toxicity of normal tissues is the most critical element of an irradiation: somatic, functional and structural alterations occur during the actual treatment itself, but late effects manifest months to years after acute effects heal, and may progress with time. The optimal therapeutic ratio ultimately requires not only complete tumor clearance, but also minimal residual injury to surrounding vital normal tissues. The disparity between the intensity of acute and late effects and the inability to predict the eventual manifestation of late normal tissue injury has made radiation oncologists recognize the importance of careful patient follow-up. There is so far no uniform toxicity scoring system to compare several clinical studies in the absence of a 'common toxicity language'. This justifies the need to establish a precise evaluation system for the analysis of late effects of radiation on normal tissues. The SOMA/LENT scoring system results from an international collaboration. European Organization Treatment of Cancer (EORTC) and Radiation Therapy Oncology Group (RTOG) have created subcommittees with the aim of addressing the question of standardized toxic effects criteria. This effort appeared as a necessity to standardize and improve the data recording, to then describe and evaluate uniform toxicity at regular time intervals. The current proposed scale is not yet validated, and should be used cautiously. (authors)

  4. Comparing Canadian and American normative scores on the Wechsler Adult Intelligence Scale-Fourth Edition.

    Science.gov (United States)

    Harrison, Allyson G; Armstrong, Irene T; Harrison, Laura E; Lange, Rael T; Iverson, Grant L

    2014-12-01

    Psychologists practicing in Canada must decide which set of normative data to use for the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV). The purpose of this study was to compare the interpretive effects of applying American versus Canadian normative systems in a sample of 432 Canadian postsecondary-level students who were administered the WAIS-IV as part of an evaluation for a learning disability, attention-deficit hyperactivity disorder, or other mental health problems. Employing the Canadian normative system yielded IQ, Index, and subtest scores that were systematically lower than those obtained using the American norms. Furthermore, the percentage agreement in normative classifications, defined as American and Canadian index scores within five points or within the same classification range, was between 49% and 76%. Substantial differences are present between the American and Canadian WAIS-IV norms. Clinicians should consider carefully the implications regarding which normative system is most appropriate for specific types of evaluations. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. CORRELATION OF MOBILE PHONE ADDICTION SCALE (MPAS SCORE WITH CRANIOVERTEBRAL ANGLE, SCAPULAR INDEX AND BECKS DEPRESSION INVENTORY SCORE IN YOUNG ADULTS

    Directory of Open Access Journals (Sweden)

    Rupali Salvi

    2018-02-01

    Full Text Available Background: Mobile phone usage has become increasingly common in today’s youth. Its heavy use often leads to an addiction. Dependency on these devices could lead to postural dysfunctions as well as produce an adverse effect on psychology. Hence, this study is done to correlate mobile addiction with the craniovertebral angle, scapular index and Beck’s depression inventory score in young adults. Methods: An observational study was performed on 100 subjects out of which 51 were males and 49 were females in the age group of 18- 25 years who were pursuing their graduation and post-graduation courses. Mobile Phone Addiction Scale was used to determine the level of addiction. Craniovertebral angle, Scapular Index, and Beck’s Depression Inventory score were measured. Correlation of Mobile Phone Addiction Scale score with the above-mentioned parameters was done using GraphPad Instat Version 3.10 (Pearson correlation coefficient and Spearman correlation coefficient. Results: Mobile phone addiction was found low in 27%, moderate in 30% and high in 43% participants. There is significant correlation of mobile phone addiction scale score with Craniovertebral angle (r = -0.6470, p = <0.0001, Scapular Index (r = -0.4370, p = < 0.001 and Beck’s depression Inventory score (r = 0.3172, p = 0.0013. Conclusion: This study shows that mobile phone addiction is common amongst the youth and it contributes to considerable stresses on neck and shoulder. It could even cause unfavorable repercussion on an individual’s psychological status, such as depression. Hence, it is important to create awareness amongst the youth and take preventive measures for the same.

  6. Using Score Equating and Measurement Invariance to Examine the Flynn Effect in the Wechsler Adult Intelligence Scale.

    Science.gov (United States)

    Benson, Nicholas; Beaujean, A Alexander; Taub, Gordon E

    2015-01-01

    The Flynn effect (FE; i.e., increase in mean IQ scores over time) is commonly viewed as reflecting population shifts in intelligence, despite the fact that most FE studies have not investigated the assumption of score comparability. Consequently, the extent to which these mean differences in IQ scores reflect population shifts in cognitive abilities versus changes in the instruments used to measure these abilities is unclear. In this study, we used modern psychometric tools to examine the FE. First, we equated raw scores for each common subtest to be on the same scale across instruments. This enabled the combination of scores from all three instruments into one of 13 age groups before converting raw scores into Z scores. Second, using age-based standardized scores for standardization samples, we examined measurement invariance across the second (revised), third, and fourth editions of the Wechsler Adult Intelligence Scale. Results indicate that while scores were equivalent across the third and fourth editions, they were not equivalent across the second and third editions. Results suggest that there is some evidence for an increase in intelligence, but also call into question many published FE findings as presuming the instruments' scores are invariant when this assumption is not warranted.

  7. An image based system to automatically and objectivelly score the degreeof redness and scaling in psoriasi lesions

    DEFF Research Database (Denmark)

    Gomez, David Delgado; Ersbøll, Bjarne Kjær; Carstensen, Jens Michael

    2004-01-01

    In this work, a combined statistical and image analysis method to automatically evaluate the severity of scaling in psoriasis lesions is proposed. The method separates the different regions of the disease in the image and scores the degree of scaling based on the properties of these areas. The pr...... that the obtained scores are highly correlated with scores made by doctors. This and the fact that the obtained measures are continuous indicate the proposed method is a suitable tool to evaluate the lesion and to track the evolution of dermatological diseases....

  8. Correlation between Manchester Grading Scale and American Orthopaedic Foot and Ankle Society Score in Patients with Hallux Valgus

    Science.gov (United States)

    Iliou, Kalliopi; Paraskevas, George; Kanavaros, Panagiotis; Barbouti, Alexandra; Vrettakos, Aristidis; Gekas, Christos; Kitsoulis, Panagiotis

    2015-01-01

    Objective To evaluate the correlation between the Manchester Grading Scale and the American Orthopaedic Foot and Ankle Society (AOFAS) score in patients with a hallux valgus deformity. Subjects and Methods The study sample included 181 feet of 122 patients with hallux valgus and 424 feet of 212 individuals without hallux valgus deformity as the control group. The severity of hallux valgus, utilizing a relative nonmetric scale, the Manchester Grading Scale, and the metric AOFAS score, was determined for all individuals in the hallux valgus and control groups. SPSS version 18 (Chicago, Ill., USA) was used for data analysis. Results According to the Manchester Grading Scale, the 424 feet of the normal group were classified as ‘no deformity−. In the hallux valgus group, 85 feet were classified as ‘mild deformity−, 67 as ‘moderate deformity' and 29 as ‘severe deformity−. The AOFAS total score in the control group was 99.14. In the hallux valgus group, patients with mild or moderate deformity had total scores of 86.20 and 68.19, respectively. For those with severe hallux valgus, the total score was 44.69 and the differences were statistically significant (p = 0.000). Using the Pearson correlation, strong negative correlations were found between the AOFAS score and the hallux valgus angle (HVA; r = −0.899, p = 0.000). Strong negative correlations were demonstrated between the AOFAS score and the first intermetatarsal angle (IMA) as well (r = −0.748, p = 0.000). Conclusions The AOFAS score was negatively associated with the Manchester Grading Scale, HVA and first IMA. As the severity of hallux valgus increased, the AOFAS score seemed to decrease. PMID:26335050

  9. Validation of Scores on the Marlowe-Crowne Social Desirability Scale and the Balanced Inventory of Desirable Responding

    Science.gov (United States)

    Leite, Walter L.; Beretvas, S. Natasha

    2005-01-01

    The Marlowe-Crowne Social Desirability Scale (MCSDS), the most commonly used social desirability bias (SDB) assessment, conceptualizes SDB as an individual's need for approval. The Balanced Inventory of Desirable Responding (BIDR) measures SDB as two separate constructs: impression management and self-deception. Scores on SDB scales are commonly…

  10. Energy analysis of Organic Rankine Cycles for biomass applications

    Directory of Open Access Journals (Sweden)

    Algieri Angelo

    2015-01-01

    Full Text Available The present paper aims at analysing the performances of Organic Rankine Cycles (ORCs adopted for the exploitation of the biomass resulting from the pruning residues in a 3000 hectares district in Southern Italy. A parametric energy analysis has been carried out to define the influence of the main plant operating conditions. To this purpose, both subcritical and transcritical power plants have been examined and saturated and superheated conditions at the turbine inlet have been imposed. Moreover, the effect of the working fluid, condensation temperature, and internal regeneration on system performances has been investigated. The results show that ORC plants represent an interesting and sustainable solution for decentralised and small-scale power production. Furthermore, the analysis highlights the significant impact of the maximum temperature and the noticeable effect of internal regeneration on the performances of the biomass power plants.

  11. Dementia knowledge assessment scale (DKAS): confirmatory factor analysis and comparative subscale scores among an international cohort.

    Science.gov (United States)

    Annear, Michael J; Toye, Chris; Elliott, Kate-Ellen J; McInerney, Frances; Eccleston, Claire; Robinson, Andrew

    2017-07-31

    Dementia is a life-limiting condition that is increasing in global prevalence in line with population ageing. In this context, it is necessary to accurately measure dementia knowledge across a spectrum of health professional and lay populations with the aim of informing targeted educational interventions and improving literacy, care, and support. Building on prior exploratory analysis, which informed the development of the preliminarily valid and reliable version of the Dementia Knowledge Assessment Scale (DKAS), a Confirmatory Factor Analysis (CFA) was performed to affirm construct validity and proposed subscales to further increase the measure's utility for academics and educators. A large, de novo sample of 3649 volunteer respondents to a dementia-related online course was recruited to evaluate the performance of the DKAS and its proposed subscales. Respondents represented diverse cohorts, including health professionals, students, and members of the general public. Analyses included CFA (using structural equation modelling), measures of internal consistency (α), and non-parametric tests of subscale correlation (Spearman Correlation) and score differences between cohorts (Kruskal-Wallis one-way analysis of variance). Findings of the CFA supported a 25-item, four-factor model for the DKAS with two items removed due to poor performance and one item moved between factors. The resultant model exhibited good reliability (α = .85; ω h  = .87; overall scale), with acceptable subscale internal consistency (α ≥ .65; subscales). Subscales showed acceptable correlation without any indication of redundancy. Finally, total and DKAS subscale scores showed good discrimination between cohorts of respondents who would be anticipated to hold different levels of knowledge on the basis of education or experience related to dementia. The DKAS has been confirmed as a reliable and valid measure of dementia knowledge for diverse populations that is capable of elucidating

  12. Organic rankine cycle waste heat applications

    Science.gov (United States)

    Brasz, Joost J.; Biederman, Bruce P.

    2007-02-13

    A machine designed as a centrifugal compressor is applied as an organic rankine cycle turbine by operating the machine in reverse. In order to accommodate the higher pressures when operating as a turbine, a suitable refrigerant is chosen such that the pressures and temperatures are maintained within established limits. Such an adaptation of existing, relatively inexpensive equipment to an application that may be otherwise uneconomical, allows for the convenient and economical use of energy that would be otherwise lost by waste heat to the atmosphere.

  13. Rankine bottoming cycle safety analysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowski, G.A.

    1980-02-01

    Vector Engineering Inc. conducted a safety and hazards analysis of three Rankine Bottoming Cycle Systems in public utility applications: a Thermo Electron system using Fluorinal-85 (a mixture of 85 mole % trifluoroethanol and 15 mole % water) as the working fluid; a Sundstrand system using toluene as the working fluid; and a Mechanical Technology system using steam and Freon-II as the working fluids. The properties of the working fluids considered are flammability, toxicity, and degradation, and the risks to both plant workers and the community at large are analyzed.

  14. Toluene stability Space Station Rankine power system

    Science.gov (United States)

    Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

    1987-01-01

    A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

  15. Correlation of Social Network Attributes with Individuals’ Score on Bipolar Spectrum Diagnostic Scale

    Directory of Open Access Journals (Sweden)

    Amir Momeni Boroujeni

    2012-09-01

    Full Text Available Introduction: Bipolar Spectrum Disorders include a variety of mood disorders from bipolar II disorder to conditions characterized by hyperthymic mood states. It has been suggested that psychosocial factors also play an important role in bipolar disorders, in this study we have used social network analysis in order to better understand the social positions of those affected by bipolar spectrum disorders. Methods: In this cross sectional study 90 individuals within a bounded network were included and studied by using a standard questionnaire for bipolar spectrum disorder scale (BSDS and a sociometric questionnaire for analyzing the social network of those individuals.Results: This study showed that BSDS score is signi.cantly correlated with the Bonacich power of the participants (P= 0.009 as well as with their Outdegree Strength (P= 0.013.Discussion: The results of this study show that there is interplay between social attributes and Bipolar Spectrum Disorders. This emphasizes the need for understanding the role of social networks and performing further research into quantifying social aspects of psychiatric disorders.

  16. Correlation of Social Network Attributes with Individuals’ Score on Bipolar Spectrum Diagnostic Scale

    Directory of Open Access Journals (Sweden)

    Amir Momeni Boroujeni

    2012-12-01

    Full Text Available Bipolar Spectrum Disorders include a variety of mood disorders from bipolar II disorder to conditions characterized by hyperthymic mood states. It has been suggested that psychosocial factors also play an important role in bipolar disorders, in this study we have used social network analysis in order to better understand the social positions of those affected by bipolar spectrum disorders.Methods and Materials: In this cross sectional study 90 individuals within a bounded network were included and studied by using a standard questionnaire for bipolar spectrum disorder scale (BSDS and a sociometric questionnaire for analyzing the social network of those individuals.Results: This study showed that BSDS score is significantly correlated with the Bonacich power of the participants (P= 0.009 as well as with their Outdegree Strength (P= 0.013.Discussion:The results of this study show that there is interplay between social attributes and Bipolar Spectrum Disorders. This emphasizes the need for understanding the role of social networks and performing further research into quantifying social aspects of psychiatric disorders.

  17. Conditional standard errors of measurement for composite scores on the Wechsler Preschool and Primary Scale of Intelligence-Third Edition.

    Science.gov (United States)

    Price, Larry R; Raju, Nambury; Lurie, Anna; Wilkins, Charles; Zhu, Jianjun

    2006-02-01

    A specific recommendation of the 1999 Standards for Educational and Psychological Testing by the American Educational Research Association, the American Psychological Association, and the National Council on Measurement in Education is that test publishers report estimates of the conditional standard error of measurement (SEM). Procedures for calculating the conditional (score-level) SEM based on raw scores are well documented; however, few procedures have been developed for estimating the conditional SEM of subtest or composite scale scores resulting from a nonlinear transformation. Item response theory provided the psychometric foundation to derive the conditional standard errors of measurement and confidence intervals for composite scores on the Wechsler Preschool and Primary Scale of Intelligence-Third Edition.

  18. Conservative treatment of soft tissue sarcomas of the extremities. Functional evaluation with LENT-SOMA scales and the Enneking score

    International Nuclear Information System (INIS)

    Tawfiq, N.; Lagarde, P.; Thomas, L.; Kantor, G.; Stockle, E.; Bui, B.N.

    2000-01-01

    Objective. - The aim of this prospective study is the feasibility of late effects assessment by LENT-SOMA scales after conservative treatment of soft tissue sarcomas of the extremities and a comparison with the functional evaluation by the Enneking score. Patients and methods. - During the systematic follow-up consultations, a series of 32 consecutive patients was evaluated in terms of late effects by LENT SOMA scales and functional results by the Enneking score. The median time after treatment was 65 months. The treatment consisted of conservative surgery (all cases) followed by radiation therapy (29 cases), often combined with adjuvant therapy (12 concomitant radio-chemotherapy association cases out of 14). The assessment of the toxicity was retrospective for acute effects and prospective for the following late tissue damage: skin/subcutaneous tissues, muscles/soft tissues and peripheral nerves. Results. -According to the Enneking score, the global score for the overall series was high (24/30) despite four the scores zero for the psychological acceptance. According to LENT SOMA scales, a low rate of severe sequelae (grade 3-4) was observed. The occurrence of high-grade sequelae and their functional consequences were not correlated with quality of exeresis, dose of radiotherapy or use of concomitant chemotherapy. A complementarity was observed between certain factors of the Enneking score and some criteria of the LENTSOMA scales, especially of muscles/soft tissues. Conclusion. -The good quality of functional results was confirmed by the two mean scoring systems for late normal tissue damage. The routine use of LENT-SOMA seems to be more time consuming than the Enneking score (mean time of scoring: 1 3 versus five minutes). The LENT-SOMA scales are aimed at a detailed description of late toxicity and sequelae while the Enneking score provides a more global evaluation, including the psychological acceptance of treatment. The late effects assessment by the LENT

  19. A comparison of low IQ scores from the Reynolds Intellectual Assessment Scales and the Wechsler Adult Intelligence Scale-Third Edition.

    Science.gov (United States)

    Umphress, Thomas B

    2008-06-01

    Twenty people with suspected intellectual disability took the Reynolds Intellectual Assessment Scales (RIAS; C. R. Reynolds & R. W. Kamphaus, 1998) and the Wechsler Adult Intelligence Scale-3rd Edition (WAIS-III; D. Wechsler, 1997) to see if the 2 IQ tests produced comparable results. A t test showed that the RIAS Composite Intelligence Index scores were significantly higher than WAIS-III Full Scale IQ scores at the alpha level of .01. There was a significant difference between the RIAS Nonverbal Intelligence and WAIS-III Performance Scale, but there was no significant difference between the RIAS Verbal Intelligence Index and the WAIS-III Verbal Scale IQ. The results raise questions concerning test selection for diagnosing intellectual disability and the use of the correlation statistic for comparing intelligence tests.

  20. Circadian variability of the initial Glasgow Coma Scale score in traumatic brain injury patients

    Directory of Open Access Journals (Sweden)

    John K. Yue

    2017-01-01

    Conclusions: Nighttime TBI patients present with decreased GCS scores and are admitted to ICU at higher rates, yet have fewer prior comorbidities and similar systemic injuries. The interaction between nighttime hours and decreased GCS score on ICU admissions has important implications for clinical assessment/triage.

  1. Robust Scale Transformation Methods in IRT True Score Equating under Common-Item Nonequivalent Groups Design

    Science.gov (United States)

    He, Yong

    2013-01-01

    Common test items play an important role in equating multiple test forms under the common-item nonequivalent groups design. Inconsistent item parameter estimates among common items can lead to large bias in equated scores for IRT true score equating. Current methods extensively focus on detection and elimination of outlying common items, which…

  2. Using Raters from India to Score a Large-Scale Speaking Test

    Science.gov (United States)

    Xi, Xiaoming; Mollaun, Pam

    2011-01-01

    We investigated the scoring of the Speaking section of the Test of English as a Foreign Language[TM] Internet-based (TOEFL iBT[R]) test by speakers of English and one or more Indian languages. We explored the extent to which raters from India, after being trained and certified, were able to score the TOEFL examinees with mixed first languages…

  3. Malingering in Toxic Exposure. Classification Accuracy of Reliable Digit Span and WAIS-III Digit Span Scaled Scores

    Science.gov (United States)

    Greve, Kevin W.; Springer, Steven; Bianchini, Kevin J.; Black, F. William; Heinly, Matthew T.; Love, Jeffrey M.; Swift, Douglas A.; Ciota, Megan A.

    2007-01-01

    This study examined the sensitivity and false-positive error rate of reliable digit span (RDS) and the WAIS-III Digit Span (DS) scaled score in persons alleging toxic exposure and determined whether error rates differed from published rates in traumatic brain injury (TBI) and chronic pain (CP). Data were obtained from the files of 123 persons…

  4. Cross Racial Identity Scale (CRIS) scores and profiles in African American adolescents involved with the juvenile justice system.

    Science.gov (United States)

    Worrell, Frank C; Andretta, James R; Woodland, Malcolm H

    2014-10-01

    In this study, we examined the internal consistency and structural validity of Cross Racial Identity Scale (CRIS) scores in a sample of 477 African American adolescents who had been arrested in a city in the mid-Atlantic. Using cluster analysis, we also identified profiles of CRIS scores and compared adolescents with different profiles on Major Depressive Episode, Manic Episode, Generalized Anxiety Disorder, and Obsessive-Compulsive Disorder scores. Results indicated that CRIS subscale scores were reliable, and the 6-factor structure of the CRIS was supported. Five nigrescence profiles were identified: Miseducation-Pro-Black, Conflicted-Self-Hatred, Multiculturalist, Low Race Salience, and Conflicted-Anti-White. Individuals with Conflicted-Self-Hatred profiles reported significantly and meaningfully higher scores on the 4 syndromes than did their peers, and individuals with the Multiculturalist and Low Race Salience profiles reported the lowest scores. A greater percentage of individuals with Conflicted racial identity profiles had syndrome scores in the clinically significant range. The results of this study demonstrate that some of the nigrescence profiles found in college-age students generalize to adolescents. The implications of the findings for theory, research, and practice are discussed. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  5. Evaluation of novel scoring system named 5-5-5 exacerbation grading scale for allergic conjunctivitis disease.

    Science.gov (United States)

    Shoji, Jun; Inada, Noriko; Sawa, Mitsuru

    2009-12-01

    The objective of this study is to evaluate the practical usefulness of a scoring system using the 5-5-5 exacerbation grading scale for allergic conjunctivitis disease (ACD). Subjects were 103 patients with ACD including 40 patients with vernal keratoconjunctivitis (VKC), 20 patients with atopic keratoconjunctivitis (AKC), and 43 patients with allergic conjunctivitis (AC). The 5-5-5 exacerbation grading scale consists of the following 3 graded groups of clinical observations: the 100-point-grade group (100 points for each observation) includes active giant papillae, gelatinous infiltrates of the limbus, exfoliative epithelial keratopathy, shield ulcer and papillary proliferation at lower palpebral conjunctiva; the 10-point-grade group (10 points for each observation) includes blepharitis, papillary proliferation with velvety appearance, Horner-Trantas spots, edema of bulbal conjunctiva, and superficial punctate keratopathy; and the 1-point-grade group (1 point for each observation) includes papillae at upper palpebral conjunctiva, follicular lesion at lower palpebral conjunctiva, hyperemia of palpebral conjunctiva, hyperemia of bulbal conjunctiva, and lacrimal effusion. The total points in each grade group were determined as the severity score of the 5-5-5 exacerbation grading scale. The median severity scores of the 5-5-5 exacerbation grading scale in VKC, AKC and AC were 243 (range: 12-444), 32.5 (11-344), and 13 (2-33), respectively. The severity score of each ACD disease type was significantly different (P Kruskal-Wallis test). The severity of each type of ACD was classified as severe, moderate, or mild according to the severity score. The 5-5-5 exacerbation grading scale is a useful clinical tool for grading the severity of each type of ACD.

  6. Establishing the cut-off score for remission and severity-ranges on the Psychotic Depression Assessment Scale (PDAS)

    DEFF Research Database (Denmark)

    Østergaard, Søren D; Rothschild, Anthony J; Flint, Alastair J

    2016-01-01

    BACKGROUND: The Psychotic Depression Assessment Scale (PDAS) is a rating scale dedicated to the measurement of severity in psychotic depression (PD). The aim of this study was to establish the PDAS cut-off for remission of PD as well as PDAS score-ranges for mild, moderate, and severe PD...... on the PDAS and the severity-ranges for mild, moderate, and severe PD were defined using the Clinical Global Impression - Severity scale (CGI-S) as reference by means of pair-wise receiver operating characteristic (ROC) analyses. Subsequently, it was tested whether remission on the PDAS could separate...... the effects of Olanzapine+Sertraline vs. Olanzapine+Placebo through an intention-to-treat, mixed-effects logistic regression of the data from STOP-PD. RESULTS: According to the ROC analyses, the ideal cut-off for remission of PD was a PDAS total score moderate...

  7. Analysis of a combined Rankine-vapour-compression refrigeration cycle

    International Nuclear Information System (INIS)

    Aphornratana, Satha; Sriveerakul, Thanarath

    2010-01-01

    This paper describes a theoretical analysis of a heat-powered refrigeration cycle, a combined Rankine-vapour-compression refrigeration cycle. This refrigeration cycle combines an Organic Rankine Cycle and a vapour-compression cycle. The cycle can be powered by low grade thermal energy as low as 60 deg. C and can produce cooling temperature as low as -10 deg. C. In the analysis, two combined Rankine-vapour-compression refrigeration cycles were investigated: the system with R22 and the system with R134a. Calculated COP values between 0.1 and 0.6 of both the systems were found.

  8. Reliability and Validity of the New Tanaka B Intelligence Scale Scores: A Group Intelligence Test

    OpenAIRE

    Uno, Yota; Mizukami, Hitomi; Ando, Masahiko; Yukihiro, Ryoji; Iwasaki, Yoko; Ozaki, Norio

    2014-01-01

    OBJECTIVE: The present study evaluated the reliability and concurrent validity of the new Tanaka B Intelligence Scale, which is an intelligence test that can be administered on groups within a short period of time. METHODS: The new Tanaka B Intelligence Scale and Wechsler Intelligence Scale for Children-Third Edition were administered to 81 subjects (mean age ± SD 15.2 ± 0.7 years) residing in a juvenile detention home; reliability was assessed using Cronbach's alpha coefficient, and concurre...

  9. Sensitivity and Specificity of the Coma Recovery Scale--Revised Total Score in Detection of Conscious Awareness.

    Science.gov (United States)

    Bodien, Yelena G; Carlowicz, Cecilia A; Chatelle, Camille; Giacino, Joseph T

    2016-03-01

    To describe the sensitivity and specificity of Coma Recovery Scale-Revised (CRS-R) total scores in detecting conscious awareness. Data were retrospectively extracted from the medical records of patients enrolled in a specialized disorders of consciousness (DOC) program. Sensitivity and specificity analyses were completed using CRS-R-derived diagnoses of minimally conscious state (MCS) or emerged from minimally conscious state (EMCS) as the reference standard for conscious awareness and the total CRS-R score as the test criterion. A receiver operating characteristic curve was constructed to demonstrate the optimal CRS-R total cutoff score for maximizing sensitivity and specificity. Specialized DOC program. Patients enrolled in the DOC program (N=252, 157 men; mean age, 49y; mean time from injury, 48d; traumatic etiology, n=127; nontraumatic etiology, n=125; diagnosis of coma or vegetative state, n=70; diagnosis of MCS or EMCS, n=182). Not applicable. Sensitivity and specificity of CRS-R total scores in detecting conscious awareness. A CRS-R total score of 10 or higher yielded a sensitivity of .78 for correct identification of patients in MCS or EMCS, and a specificity of 1.00 for correct identification of patients who did not meet criteria for either of these diagnoses (ie, were diagnosed with vegetative state or coma). The area under the curve in the receiver operating characteristic curve analysis is .98. A total CRS-R score of 10 or higher provides strong evidence of conscious awareness but resulted in a false-negative diagnostic error in 22% of patients who demonstrated conscious awareness based on CRS-R diagnostic criteria. A cutoff score of 8 provides the best balance between sensitivity and specificity, accurately classifying 93% of cases. The optimal total score cutoff will vary depending on the user's objective. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  10. Higher stress scores for female medical students measured by the Kessler Psychological Distress Scale (K10 in Pakistan

    Directory of Open Access Journals (Sweden)

    Khadija Qamar

    2014-10-01

    Full Text Available The aim of this study was to determine the stress level of medical students and the relationship between stress and academic year. A cross-sectional, descriptive study was conducted at an undergraduate medical school with a five-year curriculum, in Pakistan, from January 2014 to April 2014. Medical students in the first four years were included in the study. The Kessler Psychological Distress Scale (K10, a self-administered questionnaire, was distributed to the students. A total of 445 medical students completed the questionnaire. The average stress score was 19.61 (SD = 6.76 with a range from 10 to 43. Stress was experienced by 169 students (41.7%. The scores of female students were higher than scores of males, indicating a higher stress level (P = 0.011. The relationship between stress and academic year was insignificant (P = 0.392.

  11. [Golf handicap score is a suitable scale for monitoring rehabilitation after apoplexia cerebri].

    Science.gov (United States)

    Jensen, Per; Meden, Per; Knudsen, Lars V; Knudsen, G M; Thomsen, Carsten; Feng, Ling; Pinborg, Lars H

    2015-12-21

    A 67-year-old male was examined nine, 35 and 135 days after stroke using conventional stroke scales, 18 holes of golf, functional MRI (fist closures) and translocator protein imaging of microglial function in the brain using single photon emission computed tomography. The data showed that the over 100-year-old golf handicap scale is better suited for quantifying recovery after stroke than conventional stroke assessment scales, which are prone to ceiling effect. We suggest that rating with golf handicap should be used more widely in stroke research, and we find it tremendously important that these new findings are published before Christmas.

  12. Wechsler Adult Intelligence Scale-Third Edition short form for index and IQ scores in a psychiatric population.

    Science.gov (United States)

    Christensen, Bruce K; Girard, Todd A; Bagby, R Michael

    2007-06-01

    An eight-subtest short form (SF8) of the Wechsler Adult Intelligence Scale, Third Edition (WAIS-III), maintaining equal representation of each index factor, was developed for use with psychiatric populations. Data were collected from a mixed inpatient/outpatient sample (99 men and 101 women) referred for neuropsychological assessment. Psychometric analyses revealed an optimal SF8 comprising Vocabulary, Similarities, Arithmetic, Digit Span, Picture Completion, Matrix Reasoning, Digit Symbol Coding, and Symbol Search, scored by linear scaling. Expanding on previous short forms, the current SF8 maximizes the breadth of information and reduces administration time while maintaining the original WAIS-III factor structure. (c) 2007 APA, all rights reserved

  13. The London handicap scale: a re-evaluation of its validity using standard scoring and simple summation

    OpenAIRE

    Jenkinson, C.; Mant, J.; Carter, J.; Wade, D.; Winner, S.

    2000-01-01

    OBJECTIVE—To assess the validity of the London handicap scale (LHS) using a simple unweighted scoring system compared with traditional weighted scoring
METHODS—323 patients admitted to hospital with acute stroke were followed up by interview 6 months after their stroke as part of a trial looking at the impact of a family support organiser. Outcome measures included the six item LHS, the Dartmouth COOP charts, the Frenchay activities index, the Barthel index, and the hospital...

  14. Conversion between mini-mental state examination, montreal cognitive assessment, and dementia rating scale-2 scores in Parkinson's disease.

    Science.gov (United States)

    van Steenoven, Inger; Aarsland, Dag; Hurtig, Howard; Chen-Plotkin, Alice; Duda, John E; Rick, Jacqueline; Chahine, Lama M; Dahodwala, Nabila; Trojanowski, John Q; Roalf, David R; Moberg, Paul J; Weintraub, Daniel

    2014-12-01

    Cognitive impairment is one of the earliest, most common, and most disabling non-motor symptoms in Parkinson's disease (PD). Thus, routine screening of global cognitive abilities is important for the optimal management of PD patients. Few global cognitive screening instruments have been developed for or validated in PD patients. The Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Dementia Rating Scale-2 (DRS-2) have been used extensively for cognitive screening in both clinical and research settings. Determining how to convert the scores between instruments would facilitate the longitudinal assessment of cognition in clinical settings and the comparison and synthesis of cognitive data in multicenter and longitudinal cohort studies. The primary aim of this study was to apply a simple and reliable algorithm for the conversion of MoCA to MMSE scores in PD patients. A secondary aim was to apply this algorithm for the conversion of DRS-2 to both MMSE and MoCA scores. The cognitive performance of a convenience sample of 360 patients with idiopathic PD was assessed by at least two of these cognitive screening instruments. We then developed conversion scores between the MMSE, MoCA, and DRS-2 using equipercentile equating and log-linear smoothing. The conversion score tables reported here enable direct and easy comparison of three routinely used cognitive screening assessments in PD patients. © 2014 International Parkinson and Movement Disorder Society.

  15. Evaluation of stratification factors and score-scales in clinical trials of treatment of clinical mastitis in dairy cows.

    Science.gov (United States)

    Hektoen, L; Ødegaard, S A; Løken, T; Larsen, S

    2004-05-01

    There is often a need to reduce sample size in clinical trials due to practical limitations and ethical considerations. Better comparability between treatment groups by use of stratification in the design, and use of continuous outcome variables in the evaluation of treatment results, are two methods that can be used in order to achieve this. In this paper the choice of stratification factors in trials of clinical mastitis in dairy cows is investigated, and two score-scales for evaluation of clinical mastitis are introduced. The outcome in 57 dairy cows suffering from clinical mastitis and included in a clinical trial comparing homeopathic treatment, placebo and a standard antibiotic treatment is investigated. The strata of various stratification factors are compared across treatments to determine which other factors influence outcome. The two score scales, measuring acute and chronic mastitis symptoms, respectively, are evaluated on their ability to differentiate between patients classified from clinical criteria as responders or non-responders to treatment. Differences were found between the strata of the factors severity of mastitis, lactation number, previous mastitis this lactation and bacteriological findings. These factors influence outcome of treatment and appear relevant as stratification factors in mastitis trials. Both score scales differentiated between responders and non-responders to treatment and were found useful for evaluation of mastitis and mastitis treatment.

  16. Inclusion of Highest Glasgow Coma Scale Motor Component Score in Mortality Risk Adjustment for Benchmarking of Trauma Center Performance.

    Science.gov (United States)

    Gomez, David; Byrne, James P; Alali, Aziz S; Xiong, Wei; Hoeft, Chris; Neal, Melanie; Subacius, Harris; Nathens, Avery B

    2017-12-01

    The Glasgow Coma Scale (GCS) is the most widely used measure of traumatic brain injury (TBI) severity. Currently, the arrival GCS motor component (mGCS) score is used in risk-adjustment models for external benchmarking of mortality. However, there is evidence that the highest mGCS score in the first 24 hours after injury might be a better predictor of death. Our objective was to evaluate the impact of including the highest mGCS score on the performance of risk-adjustment models and subsequent external benchmarking results. Data were derived from the Trauma Quality Improvement Program analytic dataset (January 2014 through March 2015) and were limited to the severe TBI cohort (16 years or older, isolated head injury, GCS ≤8). Risk-adjustment models were created that varied in the mGCS covariates only (initial score, highest score, or both initial and highest mGCS scores). Model performance and fit, as well as external benchmarking results, were compared. There were 6,553 patients with severe TBI across 231 trauma centers included. Initial and highest mGCS scores were different in 47% of patients (n = 3,097). Model performance and fit improved when both initial and highest mGCS scores were included, as evidenced by improved C-statistic, Akaike Information Criterion, and adjusted R-squared values. Three-quarters of centers changed their adjusted odds ratio decile, 2.6% of centers changed outlier status, and 45% of centers exhibited a ≥0.5-SD change in the odds ratio of death after including highest mGCS score in the model. This study supports the concept that additional clinical information has the potential to not only improve the performance of current risk-adjustment models, but can also have a meaningful impact on external benchmarking strategies. Highest mGCS score is a good potential candidate for inclusion in additional models. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Predicting SF-6D utility scores from the Oswestry disability index and numeric rating scales for back and leg pain.

    Science.gov (United States)

    Carreon, Leah Y; Glassman, Steven D; McDonough, Christine M; Rampersaud, Raja; Berven, Sigurd; Shainline, Michael

    2009-09-01

    Cross-sectional cohort. The purpose of this study is to provide a model to allow estimation of utility from the Short Form (SF)-6D using data from the Oswestry Disability Index (ODI), Back Pain Numeric Rating Scale (BPNRS), and the Leg Pain Numeric Rating Scale (LPNRS). Cost-utility analysis provides important information about the relative value of interventions and requires a measure of utility not often available from clinical trial data. The ODI and numeric rating scales for back (BPNRS) and leg pain (LPNRS), are widely used disease-specific measures for health-related quality of life in patients with lumbar degenerative disorders. The purpose of this study is to provide a model to allow estimation of utility from the SF-6D using data from the ODI, BPNRS, and the LPNRS. SF-36, ODI, BPNRS, and LPNRS were prospectively collected before surgery, at 12 and 24 months after surgery in 2640 patients undergoing lumbar fusion for degenerative disorders. Spearman correlation coefficients for paired observations from multiple time points between ODI, BPNRS, and LPNRS, and SF-6D utility scores were determined. Regression modeling was done to compute the SF-6D score from the ODI, BPNRS, and LPNRS. Using a separate, independent dataset of 2174 patients in which actual SF-6D and ODI scores were available, the SF-6D was estimated for each subject and compared to their actual SF-6D. In the development sample, the mean age was 52.5 +/- 15 years and 34% were male. In the validation sample, the mean age was 52.9 +/- 14.2 years and 44% were male. Correlations between the SF-6D and the ODI, BPNRS, and LPNRS were statistically significant (P < 0.0001) with correlation coefficients of 0.82, 0.78, and 0.72, respectively. The regression equation using ODI, BPNRS,and LPNRS to predict SF-6D had an R of 0.69 and a root mean square error of 0.076. The model using ODI alone had an R of 0.67 and a root mean square error of 0.078. The correlation coefficient between the observed and estimated

  18. Performance on large-scale science tests: Item attributes that may impact achievement scores

    Science.gov (United States)

    Gordon, Janet Victoria

    Significant differences in achievement among ethnic groups persist on the eighth-grade science Washington Assessment of Student Learning (WASL). The WASL measures academic performance in science using both scenario and stand-alone question types. Previous research suggests that presenting target items connected to an authentic context, like scenario question types, can increase science achievement scores especially in underrepresented groups and thus help to close the achievement gap. The purpose of this study was to identify significant differences in performance between gender and ethnic subgroups by question type on the 2005 eighth-grade science WASL. MANOVA and ANOVA were used to examine relationships between gender and ethnic subgroups as independent variables with achievement scores on scenario and stand-alone question types as dependent variables. MANOVA revealed no significant effects for gender, suggesting that the 2005 eighth-grade science WASL was gender neutral. However, there were significant effects for ethnicity. ANOVA revealed significant effects for ethnicity and ethnicity by gender interaction in both question types. Effect sizes were negligible for the ethnicity by gender interaction. Large effect sizes between ethnicities on scenario question types became moderate to small effect sizes on stand-alone question types. This indicates the score advantage the higher performing subgroups had over the lower performing subgroups was not as large on stand-alone question types compared to scenario question types. A further comparison examined performance on multiple-choice items only within both question types. Similar achievement patterns between ethnicities emerged; however, achievement patterns between genders changed in boys' favor. Scenario question types appeared to register differences between ethnic groups to a greater degree than stand-alone question types. These differences may be attributable to individual differences in cognition

  19. Efficiency optimization potential in supercritical Organic Rankine Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, A.; Aumann, R. [Technische Universitaet Muenchen Institute of Energy Systems Boltzmannstr. 15, 85748 Garching (Germany); Karellas, S. [National Technical University of Athens Laboratory of Steam Boilers and Thermal Plants Heroon Polytechniou 9, 15780 Athens (Greece)

    2010-02-15

    Nowadays, the use of Organic Rankine Cycle (ORC) in decentralised applications is linked with the fact that this process allows the use of low temperature heat sources and offers an advantageous efficiency in small-scale concepts. Many state-of-the-art and innovative applications can successfully use the ORC process. In this process, according to the heat source level, special attention must be drawn to the choice of the appropriate working fluid, which is a factor that affects the thermal and exergetic efficiency of the cycle. The investigation of supercritical parameters of various working fluids in ORC applications seems to bring promising results concerning the efficiency of the application. This paper presents the results from a simulation of the ORC and the optimization potential of the process when using supercritical parameters. In order to optimize the process, various working fluids are considered and compared concerning their thermal efficiency and the usable percentage of heat. The reduction of exergy losses is discussed based on the need of surplus heat exchanger surface. (author)

  20. An automated four-point scale scoring of segmental wall motion in echocardiography using quantified parametric images

    International Nuclear Information System (INIS)

    Kachenoura, N; Delouche, A; Ruiz Dominguez, C; Frouin, F; Diebold, B; Nardi, O

    2010-01-01

    The aim of this paper is to develop an automated method which operates on echocardiographic dynamic loops for classifying the left ventricular regional wall motion (RWM) in a four-point scale. A non-selected group of 37 patients (2 and 4 chamber views) was studied. Each view was segmented according to the standardized segmentation using three manually positioned anatomical landmarks (the apex and the angles of the mitral annulus). The segmented data were analyzed by two independent experienced echocardiographists and the consensual RWM scores were used as a reference for comparisons. A fast and automatic parametric imaging method was used to compute and display as static color-coded parametric images both temporal and motion information contained in left ventricular dynamic echocardiograms. The amplitude and time parametric images were provided to a cardiologist for visual analysis of RWM and used for RWM quantification. A cross-validation method was applied to the segmental quantitative indices for classifying RWM in a four-point scale. A total of 518 segments were analyzed. Comparison between visual interpretation of parametric images and the reference reading resulted in an absolute agreement (Aa) of 66% and a relative agreement (Ra) of 96% and kappa (κ) coefficient of 0.61. Comparison of the automated RWM scoring against the same reference provided Aa = 64%, Ra = 96% and κ = 0.64 on the validation subset. Finally, linear regression analysis between the global quantitative index and global reference scores as well as ejection fraction resulted in correlations of 0.85 and 0.79. A new automated four-point scale scoring of RWM was developed and tested in a non-selected database. Its comparison against a consensual visual reading of dynamic echocardiograms showed its ability to classify RWM abnormalities.

  1. RSE-40: An Alternate Scoring System for the Rosenberg Self-Esteem Scale (RSE).

    Science.gov (United States)

    Wallace, Gaylen R.

    The Rosenberg Self-Esteem Inventory (RSE) is a 10-item scale purporting to measure self-esteem using self-acceptance and self-worth statements. This analysis covers concerns about the degree to which the RSE items represent a particular content universe, the RSE's applicability, factor analytic methods used, and the RSE's reliability and validity.…

  2. The Factor Structure of Preschool Learning Behaviors Scale Scores in Peruvian Children

    Science.gov (United States)

    Hahn, Kathryn R.; Schaefer, Barbara A.; Merino, Cesar; Worrell, Frank C.

    2009-01-01

    The factor structure of the Escala de Conductas de Aprendizaje Preescolar (ECAP), a Spanish translation of the Preschool Learning Behaviors Scale (PLBS), was examined in this study. Children aged 2 to 6 years (N = 328) enrolled in public and private preschools in the Republic of Peru were rated by classroom teachers on the frequency of observable,…

  3. The Development and Validation of Scores on the Mathematics Information Processing Scale (MIPS).

    Science.gov (United States)

    Bessant, Kenneth C.

    1997-01-01

    This study reports on the development and psychometric properties of a new 87-item Mathematics Information Processing Scale that explores learning strategies, metacognitive problem-solving skills, and attentional deployment. Results with 340 college students support the use of the instrument, for which factor analysis identified five theoretically…

  4. Determining minimally important score differences in scales of the Copenhagen Psychosocial Questionnaire

    DEFF Research Database (Denmark)

    Pejtersen, Jan Hyld; Bjorner, Jakob Bue; Hasle, Peter

    2010-01-01

    AIM: To determine minimally important differences (MIDs) for scales in the first version of the Copenhagen Psychosocial Questionnaire (COPSOQ). METHODS: Data were taken from two separate studies: a national population survey (N = 1062), and an intervention study at 14 workplaces (N = 1505). On th...

  5. Validity Evidence for the Interpretation and Use of Essential Elements of Communication Global Rating Scale Scores

    Science.gov (United States)

    Schneider, Nancy Rhoda

    2015-01-01

    Purpose. Clinical communication influences health outcomes, so medical schools are charged to prepare future physicians with the skills they need to interact effectively with patients. Communication leaders at The University of New Mexico School of Medicine (UNMSOM) developed The Essential Elements of Communication-Global Rating Scale (EEC-GRS) to…

  6. Associations between MMPI-2-RF validity scale scores and extra-test measures of personality and psychopathology.

    Science.gov (United States)

    Forbey, Johnathan D; Lee, Tayla T C; Ben-Porath, Yossef S; Arbisi, Paul A; Gartland, Diane

    2013-08-01

    The current study explored associations between two potentially invalidating self-report styles detected by the Validity scales of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF), over-reporting and under-reporting, and scores on the MMPI-2-RF substantive, as well as eight collateral self-report measures administered either at the same time or within 1 to 10 days of MMPI-2-RF administration. Analyses were conducted with data provided by college students, male prisoners, and male psychiatric outpatients from a Veterans Administration facility. Results indicated that if either an over- or under-reporting response style was suggested by the MMPI-2-RF Validity scales, scores on the majority of the MMPI-2-RF substantive scales, as well as a number of collateral measures, were significantly affected in all three groups in the expected directions. Test takers who were identified as potentially engaging in an over- or under-reporting response style by the MMPI-2-RF Validity scales appeared to approach extra-test measures similarly regardless of when these measures were administered in relation to the MMPI-2-RF. Limitations and suggestions for future study are discussed.

  7. [Correlation between dental pulp demyelination degree and pain visual analogue scale scores data under acute and chronic pulpitis].

    Science.gov (United States)

    Korsantiia, N B; Davarashvili, X T; Gogiashvili, L E; Mamaladze, M T; Tsagareli, Z G; Melikadze, E B

    2013-05-01

    The aim of study is the analysis of pulp nerve fibers demyelination degree and its relationship with Visual Analogue Scale (VAS) score that may be measured as objective criteria. Material and methods of study. Step I: electron micrografs of dental pulp simples with special interest of myelin structural changes detected in 3 scores system, obtained from 80 patients, displays in 4 groups: 1) acute and 2) chronic pulpitis without and with accompined systemic deseases, 20 patients in each group. Dental care was realized in Kutaisi N1 Dental clinic. Step II - self-reported VAS used for describing dental pain. All data were performed by SPSS 10,0 version statistics including Spearmen-rank and Mann-Whitny coefficients for examine the validity between pulp demyelination degree and pain intensity in verbal, numbered and box scales. Researched Data were shown that damaged myelin as focal decomposition of membranes and Schwann cells hyperthrophia correspond with acute dental pain intensity as Spearman index reported in VAS numbered Scales, myelin and axoplasm degeneration as part of chronic gangrenous pulpitis disorders are in direct correlation with VAS in verbal, numbered and behavioral Rating Scales. In fact, all morphological and subjective data, including psychomotoric assessment of dental painin pulpitis may be used in dental practice for evaluation of pain syndrome considered personal story.

  8. Normative scores on the Berg Balance Scale decline after age 70 years in healthy community-dwelling people: a systematic review.

    Science.gov (United States)

    Downs, Stephen; Marquez, Jodie; Chiarelli, Pauline

    2014-06-01

    What is the mean Berg Balance Scale score of healthy elderly people living in the community and how does it vary with age? How much variability in Berg Balance Scale scores is present in groups of healthy elderly people and how does this vary with age? Systematic review with meta-analysis. Any group of healthy community-dwelling people with a mean age of 70 years or greater that has undergone assessment using the Berg Balance Scale. Mean and standard deviations of Berg Balance Scale scores within cohorts of elderly people of known mean age. The search yielded 17 relevant studies contributing data from a total of 1363 participants. The mean Berg Balance Scale scores ranged from 37 to 55 out of a possible maximum score of 56. The standard deviation of Berg Balance Scale scores varied from 1.0 to 9.2. Although participants aged around 70 years had very close to normal Berg Balance Scale scores, there was a significant decline in balance with age at a rate of 0.7 points on the 56-point Berg Balance Scale per year. There was also a strong association between increasing age and increasing variability in balance (R(2) = 0.56, p balance deficits, as measured by the Berg Balance Scale, although balance scores deteriorate and become more variable with age. Copyright © 2014. Published by Elsevier B.V.

  9. A comparison of intraoperative morphine sulfate and methadone hydrochloride on postoperative visual analogue scale pain scores and narcotic requirements.

    Science.gov (United States)

    Laur, D F; Sinkovich, J; Betley, K

    1995-02-01

    Morphine sulfate and methadone hydrochloride exhibit very different half-lives but are described as having an analgesic potency of one. The use of a drug like methadone may provide prolonged and constant analgesia in the perioperative setting. This double-blinded investigation used methadone and morphine intraoperatively and measured pain scores and narcotic requirements in the first 24 hours postoperatively. Thirty American Society of Anesthesiology (ASA) patients, physical status I through III, between the ages of 18 to 65 years were scheduled for orthopedic surgery and randomly assigned to receive morphine or methadone at 0.30 mg/kg. Fifteen patients received morphine and fifteen patients received methadone. There was no significant difference between the two groups in terms of age, height, weight, and ASA status. No statistically significant difference was observed among the two groups between the amount of analgesic requirements postoperatively or in the visual analogue scale pain score.

  10. Ocean Thermal Energy Conversion Using Double-Stage Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Yasuyuki Ikegami

    2018-03-01

    Full Text Available Ocean Thermal Energy Conversion (OTEC using non-azeotropic mixtures such as ammonia/water as working fluid and the multistage cycle has been investigated in order to improve the thermal efficiency of the cycle because of small ocean temperature differences. The performance and effectiveness of the multistage cycle are barely understood. In addition, previous evaluation methods of heat exchange process cannot clearly indicate the influence of the thermophysical characteristics of the working fluid on the power output. Consequently, this study investigated the influence of reduction of the irreversible losses in the heat exchange process on the system performance in double-stage Rankine cycle using pure working fluid. Single Rankine, double-stage Rankine and Kalina cycles were analyzed to ascertain the system characteristics. The simple evaluation method of the temperature difference between the working fluid and the seawater is applied to this analysis. From the results of the parametric performance analysis it can be considered that double-stage Rankine cycle using pure working fluid can reduce the irreversible losses in the heat exchange process as with the Kalina cycle using an ammonia/water mixture. Considering the maximum power efficiency obtained in the study, double-stage Rankine and Kalina cycles can improve the power output by reducing the irreversible losses in the cycle.

  11. Sequence analysis of annually normalized citation counts: an empirical analysis based on the characteristic scores and scales (CSS) method.

    Science.gov (United States)

    Bornmann, Lutz; Ye, Adam Y; Ye, Fred Y

    2017-01-01

    In bibliometrics, only a few publications have focused on the citation histories of publications, where the citations for each citing year are assessed. In this study, therefore, annual categories of field- and time-normalized citation scores (based on the characteristic scores and scales method: 0 = poorly cited, 1 = fairly cited, 2 = remarkably cited, and 3 = outstandingly cited) are used to study the citation histories of papers. As our dataset, we used all articles published in 2000 and their annual citation scores until 2015. We generated annual sequences of citation scores (e.g., [Formula: see text]) and compared the sequences of annual citation scores of six broader fields (natural sciences, engineering and technology, medical and health sciences, agricultural sciences, social sciences, and humanities). In agreement with previous studies, our results demonstrate that sequences with poorly cited (0) and fairly cited (1) elements dominate the publication set; sequences with remarkably cited (3) and outstandingly cited (4) periods are rare. The highest percentages of constantly poorly cited papers can be found in the social sciences; the lowest percentages are in the agricultural sciences and humanities. The largest group of papers with remarkably cited (3) and/or outstandingly cited (4) periods shows an increasing impact over the citing years with the following orders of sequences: [Formula: see text] (6.01%), which is followed by [Formula: see text] (1.62%). Only 0.11% of the papers ( n  = 909) are constantly on the outstandingly cited level.

  12. Summary scores captured changes in subjects' QoL as measured by the multiple scales of the EORTC QLQ-C30.

    Science.gov (United States)

    Phillips, Rachel; Gandhi, Mihir; Cheung, Yin Bun; Findlay, Michael P; Win, Khin Maung; Hai, Hoang Hoa; Yang, Jin Mo; Lobo, Rolley Rey; Soo, Khee Chee; Chow, Pierce K H

    2015-08-01

    To examine the performance of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) global health status/quality of life (QoL) scale and two summary scores to detect changes in the QoL profile over time, according to changes in the individual scales. Data came from 167 clinical trial patients with unresectable (advanced) hepatocellular carcinoma. The global health status/QoL scale of the questionnaire contained two items: overall health and overall QoL. Nordin and Hinz proposed summary scores for the questionnaire. A mixed-effect model was fitted to estimate trends in scores over time. Predominantly the individual scale scores declined over time; however, the global health status/QoL score was stable [rate of change = -0.3 per month; 95% confidence interval (CI): -1.2, 0.6]. Nordin's summary score, which gave equal weight to the 15 questionnaire scales, and Hinz's summary score, which gave equal weight to the 30 questionnaire items, showed a statistically significant decline over time, 3.4 (95% CI: -4.5, -2.4) and 4.2 (95% CI: -5.3, -3.0) points per month, respectively. In contrast to the global health status/QoL scale, the summary scores proposed by Nordin and Hinz detected changes in subjects' QoL profile described by the EORTC QLQ-C30 individual scales. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. [Interpreting change scores of the Behavioural Rating Scale for Geriatric Inpatients (GIP)].

    Science.gov (United States)

    Diesfeldt, H F A

    2013-09-01

    The Behavioural Rating Scale for Geriatric Inpatients (GIP) consists of fourteen, Rasch modelled subscales, each measuring different aspects of behavioural, cognitive and affective disturbances in elderly patients. Four additional measures are derived from the GIP: care dependency, apathy, cognition and affect. The objective of the study was to determine the reproducibility of the 18 measures. A convenience sample of 56 patients in psychogeriatric day care was assessed twice by the same observer (a professional caregiver). The median time interval between rating occasions was 45 days (interquartile range 34-58 days). Reproducibility was determined by calculating intraclass correlation coefficients (ICC agreement) for test-retest reliability. The minimal detectable difference (MDD) was calculated based on the standard error of measurement (SEM agreement). Test-retest reliability expressed by the ICCs varied from 0.57 (incoherent behaviour) to 0.93 (anxious behaviour). Standard errors of measurement varied from 0.28 (anxious behaviour) to 1.63 (care dependency). The results show how the GIP can be applied when interpreting individual change in psychogeriatric day care participants.

  14. Emissions-critical charge cooling using an organic rankine cycle

    Science.gov (United States)

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-07-15

    The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.

  15. The efficiency of parameter estimation of latent path analysis using summated rating scale (SRS) and method of successive interval (MSI) for transformation of score to scale

    Science.gov (United States)

    Solimun, Fernandes, Adji Achmad Rinaldo; Arisoesilaningsih, Endang

    2017-12-01

    Research in various fields generally investigates systems and involves latent variables. One method to analyze the model representing the system is path analysis. The data of latent variables measured using questionnaires by applying attitude scale model yields data in the form of score, before analyzed should be transformation so that it becomes data of scale. Path coefficient, is parameter estimator, calculated from scale data using method of successive interval (MSI) and summated rating scale (SRS). In this research will be identifying which data transformation method is better. Path coefficients have smaller varieties are said to be more efficient. The transformation method that produces scaled data and used in path analysis capable of producing path coefficients (parameter estimators) with smaller varieties is said to be better. The result of analysis using real data shows that on the influence of Attitude variable to Intention Entrepreneurship, has relative efficiency (ER) = 1, where it shows that the result of analysis using data transformation of MSI and SRS as efficient. On the other hand, for simulation data, at high correlation between items (0.7-0.9), MSI method is more efficient 1.3 times better than SRS method.

  16. Fluid selection for a low-temperature solar organic Rankine cycle

    International Nuclear Information System (INIS)

    Tchanche, Bertrand Fankam; Papadakis, George; Lambrinos, Gregory; Frangoudakis, Antonios

    2009-01-01

    Theoretical performances as well as thermodynamic and environmental properties of few fluids have been comparatively assessed for use in low-temperature solar organic Rankine cycle systems. Efficiencies, volume flow rate, mass flow rate, pressure ratio, toxicity, flammability, ODP and GWP were used for comparison. Of 20 fluids investigated, R134a appears as the most suitable for small scale solar applications. R152a, R600a, R600 and R290 offer attractive performances but need safety precautions, owing to their flammability.

  17. The Basilar Artery on Computed Tomography Angiography Prognostic Score for Basilar Artery Occlusion.

    Science.gov (United States)

    Alemseged, Fana; Shah, Darshan G; Diomedi, Marina; Sallustio, Fabrizio; Bivard, Andrew; Sharma, Gagan; Mitchell, Peter J; Dowling, Richard J; Bush, Steven; Yan, Bernard; Caltagirone, Carlo; Floris, Roberto; Parsons, Mark W; Levi, Christopher R; Davis, Stephen M; Campbell, Bruce C V

    2017-03-01

    Basilar artery occlusion is associated with high risk of disability and mortality. This study aimed to assess the prognostic value of a new radiological score: the Basilar Artery on Computed Tomography Angiography (BATMAN) score. A retrospective analysis of consecutive stroke patients with basilar artery occlusion diagnosed on computed tomographic angiography was performed. BATMAN score is a 10-point computed tomographic angiography-based grading system which incorporates thrombus burden and the presence of collaterals. Reliability was assessed with intraclass coefficient correlation. Good outcome was defined as modified Rankin Scale score of ≤3 at 3 months and successful reperfusion as thrombolysis in cerebral infarction 2b-3. BATMAN score was externally validated and compared with the Posterior Circulation Collateral score. The derivation cohort included 83 patients with 41 in the validation cohort. In receiver operating characteristic (ROC) analysis, BATMAN score had an area under receiver operating characteristic curve of 0.81 (95% confidence interval [CI], 0.7-0.9) in derivation cohort and an area under receiver operating characteristic curve of 0.74 (95% CI, 0.6-0.9) in validation cohort. In logistic regression adjusted for age and clinical severity, BATMAN score of BATMAN score of BATMAN score had greater accuracy compared with Posterior Circulation Collateral score ( P =0.04). The addition of collateral quality to clot burden in BATMAN score seems to improve prognostic accuracy in basilar artery occlusion patients. © 2017 American Heart Association, Inc.

  18. A Comparative Study of Glasgow Coma Scale and Full Outline of Unresponsiveness Scores for Predicting Long-Term Outcome After Brain Injury.

    Science.gov (United States)

    McNett, Molly M; Amato, Shelly; Philippbar, Sue Ann

    2016-01-01

    The aim of this study was to compare predictive ability of hospital Glasgow Coma Scale (GCS) scores and scores obtained using a novel coma scoring tool (the Full Outline of Unresponsiveness [FOUR] scale) on long-term outcomes among patients with traumatic brain injury. Preliminary research of the FOUR scale suggests that it is comparable with GCS for predicting mortality and functional outcome at hospital discharge. No research has investigated relationships between coma scores and outcome 12 months postinjury. This is a prospective cohort study. Data were gathered on adult patients with traumatic brain injury admitted to urban level I trauma center. GCS and FOUR scores were assigned at 24 and 72 hours and at hospital discharge. Glasgow Outcome Scale scores were assigned at 6 and 12 months. The sample size was n = 107. Mean age was 53.5 (SD = ±21, range = 18-91) years. Spearman correlations were comparable and strongest among discharge GCS and FOUR scores and 12-month outcome (r = .73, p coma scores performed best for both tools, with GCS discharge scores predictive in multivariate models.

  19. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    Science.gov (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  20. New concepts for organic Rankine cycle power systems

    NARCIS (Netherlands)

    Casati, E.I.M.

    2014-01-01

    Energy provision is one of the major challenges for the Human Society, and it is increasingly clear that the current production/consumption model is not sustainable. The envisaged energy system is smarter, more decentralised and integrated. Energy conversion systems based on the organic Rankine

  1. K-Rankine systems for piloted and cargo Mars missions

    International Nuclear Information System (INIS)

    Mills, J.C.; Rovang, R.D.; Johnson, G.A.

    1992-03-01

    Studies are performed to demonstrate the attractiveness of potassium-Rankine (K-Rankine) nuclear electric propulsion (NEP) systems for both piloted and cargo Mars missions. The key results of the piloted mission study are that a full-up piloted mission can be accomplished with a trip time of less than 390 days with an attractive initial mass in low earth orbit (IMLEO) of 700 metric tons. This is achieved by coupling two advanced cermet fuel reactors (1550 K outlet temperature) to K-Rankine power-conversion systems to produce the 46 MWe needed to power advanced ion engines. This design approach offers an alternative to a more risky split-sprint mission where comparable trip times and IMLEO can be achieved with a nearer-term reactor (SP-100 at 1350 K outlet temperature) technology. The results of the cargo-mission study indicate that a lower-power K-Rankine system (5.5 MWe) operating at SP-100 reactor conditions would best perform a representative Mars cargo transport. A round-trip mission (480 days outbound; 600 day return) to Mars requires only 225 metric tons IMLEO and permit possible system reuse. 6 refs

  2. Organic Rankine Cycle with Solar Heat Storage in Paraffin Way

    Directory of Open Access Journals (Sweden)

    Constantin LUCA

    2015-06-01

    Full Text Available The paper presents an electricity generation system based on an Organic Rankine Cycle and proposed storing the amount of the heat produced by the solar panels using large volume of paraffin wax. The proposed working fluid is R-134a refrigerant. The cycle operates at very low temperatures. A efficiency of 6,55% was obtained.

  3. 2000-2010 Annual State-Scale Service and Domain Scores for Forecasting Well-Being from Service-Based Decisions

    Data.gov (United States)

    U.S. Environmental Protection Agency — 2000-2010 Annual State-Scale Service and Domain scores used to support the approach for forecasting EPA's Human Well-Being Index. A modeling approach was developed...

  4. Seeing the Forest for the Trees: Prevalence of Low Scores on the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV)

    Science.gov (United States)

    Brooks, Brian L.

    2010-01-01

    Low scores across a battery of tests are common in healthy people and vary by demographic characteristics. The purpose of the present article was to present the base rates of low scores for the Wechsler Intelligence Scale for Children, fourth edition (WISC-IV; D. Wechsler, 2003). Participants included 2,200 children and adolescents between 6 and…

  5. Increasing thermal efficiency of Rankine cycles by using refrigeration cycles: A theoretical analysis

    International Nuclear Information System (INIS)

    Sarr, Joachim-André Raymond; Mathieu-Potvin, François

    2016-01-01

    Highlights: • A new stratagem is proposed to improve thermal efficiency of Rankine cycles. • Three new configurations are optimized by means of numerical simulations. • The Rankine-1SCR design is advantageous for 1338 different fluid combinations. • The Rankine-2SCR design is advantageous for 772 different fluid combinations. • The Rankine-3SCR design is advantageous for 768 different fluid combinations. - Abstract: In this paper, three different modifications of the basic Rankine thermodynamic cycle are proposed. The objective is to increase the thermal efficiency of power systems based on Rankine cycles. The three new systems are named “Rankine-1SCR”, “Rankine-2SCR”, and “Rankine-3SCR” cycles, and they consist of linking a refrigeration cycle to the basic Rankine cycle. The idea is to use the refrigeration cycle to create a low temperature heat sink for the Rankine cycle. These three new power plant configurations are modeled and optimized with numerical tools, and then they are compared with the basic Rankine cycle. The objective function is the thermal efficiency of the systems (i.e., net power output (kW) divided by heat rate (kW) entering the system), and the design variables are the operating temperatures within the systems. Among the 84 × 84 (i.e., 7056) possible combinations of working and cooling fluids investigated in this paper, it is shown that: (i) the Rankine-1SCR system is advantageous for 1338 different fluid combinations, (ii) the Rankine-2SCR system is advantageous for 772 different fluid combinations, and (iii) the Rankine-3SCR system is advantageous for 768 different fluid combinations.

  6. Do Multidimensional Pain Inventory scale score changes indicate risk of receiving sick leave benefits 1 year after a pain rehabilitation programme?

    DEFF Research Database (Denmark)

    Nyberg, Vanja E; Novo, Mehmed; Sjölund, Bengt H

    2011-01-01

    To study whether scale score changes in the Multidimensional Pain Inventory (MPI) can predict which persons disabled by pain will receive sick leave benefits 1 year after completing a pain rehabilitation programme.......To study whether scale score changes in the Multidimensional Pain Inventory (MPI) can predict which persons disabled by pain will receive sick leave benefits 1 year after completing a pain rehabilitation programme....

  7. CORRELATION OF MOBILE PHONE ADDICTION SCALE (MPAS) SCORE WITH CRANIOVERTEBRAL ANGLE, SCAPULAR INDEX AND BECKS DEPRESSION INVENTORY SCORE IN YOUNG ADULTS

    OpenAIRE

    Rupali Salvi; Sneha Battin

    2018-01-01

    Background: Mobile phone usage has become increasingly common in today’s youth. Its heavy use often leads to an addiction. Dependency on these devices could lead to postural dysfunctions as well as produce an adverse effect on psychology. Hence, this study is done to correlate mobile addiction with the craniovertebral angle, scapular index and Beck’s depression inventory score in young adults. Methods: An observational study was performed on 100 subjects out of which 51 were males and 49 w...

  8. Comparison of the Full Outline of UnResponsiveness score and the Glasgow Coma Scale in predicting mortality in critically ill patients*.

    Science.gov (United States)

    Wijdicks, Eelco F M; Kramer, Andrew A; Rohs, Thomas; Hanna, Susan; Sadaka, Farid; O'Brien, Jacklyn; Bible, Shonna; Dickess, Stacy M; Foss, Michelle

    2015-02-01

    Impaired consciousness has been incorporated in prediction models that are used in the ICU. The Glasgow Coma Scale has value but is incomplete and cannot be assessed in intubated patients accurately. The Full Outline of UnResponsiveness score may be a better predictor of mortality in critically ill patients. Thirteen ICUs at five U.S. hospitals. One thousand six hundred ninety-five consecutive unselected ICU admissions during a six-month period in 2012. Glasgow Coma Scale and Full Outline of UnResponsiveness score were recorded within 1 hour of admission. Baseline characteristics and physiologic components of the Acute Physiology and Chronic Health Evaluation system, as well as mortality were linked to Glasgow Coma Scale/Full Outline of UnResponsiveness score information. None. We recruited 1,695 critically ill patients, of which 1,645 with complete data could be linked to data in the Acute Physiology and Chronic Health Evaluation system. The area under the receiver operating characteristic curve of predicting ICU mortality using the Glasgow Coma Scale was 0.715 (95% CI, 0.663-0.768) and using the Full Outline of UnResponsiveness score was 0.742 (95% CI, 0.694-0.790), statistically different (p = 0.001). A similar but nonsignificant difference was found for predicting hospital mortality (p = 0.078). The respiratory and brainstem reflex components of the Full Outline of UnResponsiveness score showed a much wider range of mortality than the verbal component of Glasgow Coma Scale. In multivariable models, the Full Outline of UnResponsiveness score was more useful than the Glasgow Coma Scale for predicting mortality. The Full Outline of UnResponsiveness score might be a better prognostic tool of ICU mortality than the Glasgow Coma Scale in critically ill patients, most likely a result of incorporating brainstem reflexes and respiration into the Full Outline of UnResponsiveness score.

  9. Combining Spot Sign and Intracerebral Hemorrhage Score to Estimate Functional Outcome: Analysis From the PREDICT Cohort.

    Science.gov (United States)

    Schneider, Hauke; Huynh, Thien J; Demchuk, Andrew M; Dowlatshahi, Dar; Rodriguez-Luna, David; Silva, Yolanda; Aviv, Richard; Dzialowski, Imanuel

    2018-06-01

    The intracerebral hemorrhage (ICH) score is the most commonly used grading scale for stratifying functional outcome in patients with acute ICH. We sought to determine whether a combination of the ICH score and the computed tomographic angiography spot sign may improve outcome prediction in the cohort of a prospective multicenter hemorrhage trial. Prospectively collected data from 241 patients from the observational PREDICT study (Prediction of Hematoma Growth and Outcome in Patients With Intracerebral Hemorrhage Using the CT-Angiography Spot Sign) were analyzed. Functional outcome at 3 months was dichotomized using the modified Rankin Scale (0-3 versus 4-6). Performance of (1) the ICH score and (2) the spot sign ICH score-a scoring scale combining ICH score and spot sign number-was tested. Multivariable analysis demonstrated that ICH score (odds ratio, 3.2; 95% confidence interval, 2.2-4.8) and spot sign number (n=1: odds ratio, 2.7; 95% confidence interval, 1.1-7.4; n>1: odds ratio, 3.8; 95% confidence interval, 1.2-17.1) were independently predictive of functional outcome at 3 months with similar odds ratios. Prediction of functional outcome was not significantly different using the spot sign ICH score compared with the ICH score alone (spot sign ICH score area under curve versus ICH score area under curve: P =0.14). In the PREDICT cohort, a prognostic score adding the computed tomographic angiography-based spot sign to the established ICH score did not improve functional outcome prediction compared with the ICH score. © 2018 American Heart Association, Inc.

  10. The Use of Quality Control and Data Mining Techniques for Monitoring Scaled Scores: An Overview. Research Report. ETS RR-12-20

    Science.gov (United States)

    von Davier, Alina A.

    2012-01-01

    Maintaining comparability of test scores is a major challenge faced by testing programs that have almost continuous administrations. Among the potential problems are scale drift and rapid accumulation of errors. Many standard quality control techniques for testing programs, which can effectively detect and address scale drift for small numbers of…

  11. The use of the SF-36 questionnaire in adult survivors of childhood cancer: evaluation of data quality, score reliability, and scaling assumptions

    Directory of Open Access Journals (Sweden)

    Winter David L

    2006-10-01

    Full Text Available Abstract Background The SF-36 has been used in a number of previous studies that have investigated the health status of childhood cancer survivors, but it never has been evaluated regarding data quality, scaling assumptions, and reliability in this population. As health status among childhood cancer survivors is being increasingly investigated, it is important that the measurement instruments are reliable, validated and appropriate for use in this population. The aim of this paper was to determine whether the SF-36 questionnaire is a valid and reliable instrument in assessing self-perceived health status of adult survivors of childhood cancer. Methods We examined the SF-36 to see how it performed with respect to (1 data completeness, (2 distribution of the scale scores, (3 item-internal consistency, (4 item-discriminant validity, (5 internal consistency, and (6 scaling assumptions. For this investigation we used SF-36 data from a population-based study of 10,189 adult survivors of childhood cancer. Results Overall, missing values ranged per item from 0.5 to 2.9 percent. Ceiling effects were found to be highest in the role limitation-physical (76.7% and role limitation-emotional (76.5% scales. All correlations between items and their hypothesised scales exceeded the suggested standard of 0.40 for satisfactory item-consistency. Across all scales, the Cronbach's alpha coefficient of reliability was found to be higher than the suggested value of 0.70. Consistent across all cancer groups, the physical health related scale scores correlated strongly with the Physical Component Summary (PCS scale scores and weakly with the Mental Component Summary (MCS scale scores. Also, the mental health and role limitation-emotional scales correlated strongly with the MCS scale score and weakly with the PCS scale score. Moderate to strong correlations with both summary scores were found for the general health perception, energy/vitality, and social functioning

  12. Rankine-Brayton engine powered solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L [Livermore, CA

    2009-12-29

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  13. Exergy analysis of biomass organic Rankine cycle for power generation

    Science.gov (United States)

    Nur, T. B.; Sunoto

    2018-02-01

    The study examines proposed small biomass-fed Organic Rankine Cycle (ORC) power plant through exergy analysis. The system consists of combustion burner unit to utilize biomass as fuel, and organic Rankine cycle unit to produce power from the expander. The heat from combustion burner was transfered by thermal oil heater to evaporate ORC working fluid in the evaporator part. The effects of adding recuperator into exergy destruction were investigated. Furthermore, the results of the variations of system configurations with different operating parameters, such as the evaporating pressures, ambient temperatures, and expander pressures were analyzed. It was found that the largest exergy destruction occurs during processes are at combustion part, followed by evaporator, condenser, expander, and pump. The ORC system equipped with a recuperator unit exhibited good operational characteristics under wide range conditions compared to the one without recuperator.

  14. Scoring correction for MMPI-2 Hs scale with patients experiencing a traumatic brain injury: a test of measurement invariance.

    Science.gov (United States)

    Alkemade, Nathan; Bowden, Stephen C; Salzman, Louis

    2015-02-01

    It has been suggested that MMPI-2 scoring requires removal of some items when assessing patients after a traumatic brain injury (TBI). Gass (1991. MMPI-2 interpretation and closed head injury: A correction factor. Psychological assessment, 3, 27-31) proposed a correction procedure in line with the hypothesis that MMPI-2 endorsement may be affected by symptoms of TBI. This study assessed the validity of the Gass correction procedure. A sample of patients with a TBI (n = 242), and a random subset of the MMPI-2 normative sample (n = 1,786). The correction procedure implies a failure of measurement invariance across populations. This study examined measurement invariance of one of the MMPI-2 scales (Hs) that includes TBI correction items. A four-factor model of the MMPI-2 Hs items was defined. The factor model was found to meet the criteria for partial measurement invariance. Analysis of the change in sensitivity and specificity values implied by partial measurement invariance failed to indicate significant practical impact of partial invariance. Overall, the results support continued use of all Hs items to assess psychological well-being in patients with TBI. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Catalytic activity of autoantibodies toward myelin basic protein correlates with the scores on the multiple sclerosis expanded disability status scale.

    Science.gov (United States)

    Ponomarenko, Natalia A; Durova, Oxana M; Vorobiev, Ivan I; Belogurov, Alexey A; Telegin, Georgy B; Suchkov, Sergey V; Misikov, Victor K; Morse, Herbert C; Gabibov, Alexander G

    2006-02-28

    Autoantibodies toward myelin basic protein (MBP) evidently emerge in sera and cerebrospinal fluid of the patients with multiple sclerosis (MS), as well as in a MS rodent model, i.e., experimental autoimmune encephalomyelitis (EAE). The studies of the last two decades have unveiled somewhat controversial data on the diagnostic applicability of anti-MBP autoantibodies as a disease' marker. Here, we present the results of new functional analysis of the anti-MBP autoantibodies isolated from MS (in patients) and EAE (in mice) sera, based on their proteolytic activity against the targeted autoantigen. The activity was shown to be the intrinsic property of the IgG molecule. No activity was found in the sera-derived antibody fraction of healthy donors and control mice. Sera of 24 patients with clinically proven MS at different stages of the disease, and 20 healthy controls were screened for the anti-MBP antibody-mediated proteolytic activity. The activity correlated with the scores on the MS expanded disability status scale (EDSS) (r(2)=0.85, P<0.001). Thus, the anti-MBP autoantibody-mediated proteolysis may be regarded as an additional marker of the disease progression.

  16. Quantifying Risk of Financial Incapacity and Financial Exploitation in Community-dwelling Older Adults: Utility of a Scoring System for the Lichtenberg Financial Decision-making Rating Scale.

    Science.gov (United States)

    Lichtenberg, Peter A; Gross, Evan; Ficker, Lisa J

    2018-06-08

    This work examines the clinical utility of the scoring system for the Lichtenberg Financial Decision-making Rating Scale (LFDRS) and its usefulness for decision making capacity and financial exploitation. Objective 1 was to examine the clinical utility of a person centered, empirically supported, financial decision making scale. Objective 2 was to determine whether the risk-scoring system created for this rating scale is sufficiently accurate for the use of cutoff scores in cases of decisional capacity and cases of suspected financial exploitation. Objective 3 was to examine whether cognitive decline and decisional impairment predicted suspected financial exploitation. Two hundred independently living, non-demented community-dwelling older adults comprised the sample. Participants completed the rating scale and other cognitive measures. Receiver operating characteristic curves were in the good to excellent range for decisional capacity scoring, and in the fair to good range for financial exploitation. Analyses supported the conceptual link between decision making deficits and risk for exploitation, and supported the use of the risk-scoring system in a community-based population. This study adds to the empirical evidence supporting the use of the rating scale as a clinical tool assessing risk for financial decisional impairment and/or financial exploitation.

  17. New concepts for organic Rankine cycle power systems

    OpenAIRE

    Casati, E.I.M.

    2014-01-01

    Energy provision is one of the major challenges for the Human Society, and it is increasingly clear that the current production/consumption model is not sustainable. The envisaged energy system is smarter, more decentralised and integrated. Energy conversion systems based on the organic Rankine thermodynamic cycle (ORC) have the potential to play a major role in this framework, being one of the most proven solutions for the exploitation of external thermal sources in the power-output range fr...

  18. Energy recovery system using an organic rankine cycle

    Science.gov (United States)

    Ernst, Timothy C

    2013-10-01

    A thermodynamic system for waste heat recovery, using an organic rankine cycle is provided which employs a single organic heat transferring fluid to recover heat energy from two waste heat streams having differing waste heat temperatures. Separate high and low temperature boilers provide high and low pressure vapor streams that are routed into an integrated turbine assembly having dual turbines mounted on a common shaft. Each turbine is appropriately sized for the pressure ratio of each stream.

  19. Pb-H2O Thermogravimetric Plants. The Rankine Cycle

    International Nuclear Information System (INIS)

    Arosio, S.; Carlevaro, R.

    2000-01-01

    An economic evaluation concerning Pb-H 2 O thermogravimetric systems with an electric power in the range 200-1.000 kW has been done. Moreover, plant and running costs for a thermogravimetric and a Rankine cycle, 1 MW power, have been compared. Basically due to the lead charge, the plant cost of the former is higher: nevertheless such amount can be recuperated in less than three years, being higher the running cost of the latter [it

  20. Experimental demonstrations of organic Rankine cycle waste heat rejection systems

    Science.gov (United States)

    Bland, Timothy J.; Lacey, P. Douglas

    Two phase fluid management is an important factor in the successful design of organic Rankine cycle (ORC) power conversion systems for space applications. The evolution of the heat rejection system approach from a jet condenser, through a rotary jet condenser, to a rotary fluid management device (RFMD) with a surface condenser has been described in a previous paper. Some of the test programs that were used to prove the validity of the selected approach are described.

  1. Differences in pain measures by mini-mental state examination scores of residents in aged care facilities: examining the usability of the Abbey pain scale-Japanese version.

    Science.gov (United States)

    Takai, Yukari; Yamamoto-Mitani, Noriko; Ko, Ayako; Heilemann, Marysue V

    2014-03-01

    The validity and reliability of the Abbey Pain Scale-Japanese version (APS-J) have been examined. However, the range of cognitive levels for which the APS-J can be accurately used in older adults has not been investigated. This study aimed to examine the differences between total/item scores of the APS-J and Mini-Mental State Examination (MMSE) scores of residents in aged care facilities who self-reported the presence or absence of pain. This descriptive study included 252 residents in aged care facilities. Self-reported pain, MMSE scores, and item/total APS-J scores for pain intensity were collected. The MMSE scores were used to create four groups on the basis of the cognitive impairment level. Self-reports of pain and the APS-J scores were compared with different MMSE score groups. The total APS-J score for pain intensity as well as scores for individual items such as "vocalization" and "facial expression" were significantly higher in those who reported pain than in those reporting no pain across all MMSE groups. The total APS-J score and item scores for "vocalization," "change in body language," and "behavioral changes" showed significant differences in the four MMSE groups. Pain intensity tended to be overestimated by the APS-J, especially among those with low MMSE scores. The APS-J can be used to assess pain intensity in residents despite their cognitive levels. However, caution is required when using it to compare scores among older adults with different cognitive capacity because of the possibility of overestimation of pain among residents with low cognitive capacity. Copyright © 2014 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  2. The effect of rater training on scoring performance and scale-specific expertise amongst occupational therapists participating in a multicentre study

    DEFF Research Database (Denmark)

    Hansen, Tina; Elholm Madsen, Esben; Sørensen, Annette

    2016-01-01

    Gill Ingestive Skills Assessment (MISA) they observe, interpret and record occupational performance of dysphagic clients participating in a meal. This is a highly complex task, which might introduce unwanted variability in measurement scores. A 2-day rater training programme was developed and this builds...... of the training on scoring performance and scale-specific expertise amongst raters. METHOD: During 2 days of rater training, 81 occupational therapists (OTs) were qualified to observe and score dysphagic clients' mealtime performance according to the criteria of 36 MISA-items. The training effects were evaluated...... deficient mealtime performance appeared most difficult to score. The OTs scale-specific expertise improved significantly (knowledge: Z = -7.857, p performance when using the Danish MISA as well as their perceived...

  3. Mediterranean Diet in patients with acute ischemic stroke: Relationships between Mediterranean Diet score, diagnostic subtype, and stroke severity index.

    Science.gov (United States)

    Tuttolomondo, Antonino; Casuccio, Alessandra; Buttà, Carmelo; Pecoraro, Rosaria; Di Raimondo, Domenico; Della Corte, Vittoriano; Arnao, Valentina; Clemente, Giuseppe; Maida, Carlo; Simonetta, Irene; Miceli, Giuseppe; Lucifora, Benedetto; Cirrincione, Anna; Di Bona, Danilo; Corpora, Francesca; Maugeri, Rosario; Iacopino, Domenico Gerardo; Pinto, Antonio

    2015-11-01

    Adherence to a Mediterranean Diet appears to reduce the risk of cardiovascular disease, cancer, Alzheimer's disease, and Parkinson's disease, as well as the risk of death due to cardiovascular disease. No study has addressed the association between diagnostic subtype of stroke and its severity and adherence to a Mediterranean Diet in subjects with acute ischemic stroke. To evaluate the association between Mediterranean Diet adherence, TOAST subtype, and stroke severity by means of a retrospective study. The type of acute ischemic stroke was classified according to the TOAST criteria. All patients admitted to our ward with acute ischemic stroke completed a 137-item validated food-frequency questionnaire adapted to the Sicilian population. A scale indicating the degree of adherence to the traditional Mediterranean Diet was used (Me-Di score: range 0-9). 198 subjects with acute ischemic stroke and 100 control subjects without stroke. Stroke subjects had a lower mean Mediterranean Diet score compared to 100 controls without stroke. We observed a significant positive correlation between Me-Di score and SSS score, whereas we observed a negative relationship between Me-Di score and NIHSS and Rankin scores. Subjects with atherosclerotic (LAAS) stroke subtype had a lower mean Me-Di score compared to subjects with other subtypes. Multinomial logistic regression analysis in a simple model showed a negative relationship between MeDi score and LAAS subtype vs. lacunar subtype (and LAAS vs. cardio-embolic subtype). Patients with lower adherence to a Mediterranean Diet are more likely to have an atherosclerotic (LAAS) stroke, a worse clinical presentation of ischemic stroke at admission and a higher Rankin score at discharge. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Research in Support of the Use of Rankine Cycle Energy Conversion Systems for Space Power and Propulsion

    Science.gov (United States)

    Lahey, Richard T., Jr.; Dhir, Vijay

    2004-01-01

    This is the report of a Scientific Working Group (SWG) formed by NASA to determine the feasibility of using a liquid metal cooled nuclear reactor and Rankine energy conversion cycle for dual purpose power and propulsion in space. This is a high level technical report which is intended for use by NASA management in program planning. The SWG was composed of a team of specialists in nuclear energy and multiphase flow and heat transfer technology from academia, national laboratories, NASA and industry. The SWG has identified the key technology issues that need to be addressed and have recommended an integrated short term (approx. 2 years) and a long term (approx. 10 year) research and development (R&D) program to qualify a Rankine cycle power plant for use in space. This research is ultimately intended to give NASA and its contractors the ability to reliably predict both steady and transient multiphase flow and heat transfer phenomena at reduced gravity, so they can analyze and optimize designs and scale-up experimental data on Rankine cycle components and systems. In addition, some of these results should also be useful for the analysis and design of various multiphase life support and thermal management systems being considered by NASA.

  5. Evidence for the Psychometric Validity, Internal Consistency and Measurement Invariance of Warwick Edinburgh Mental Well-being Scale Scores in Scottish and Irish Adolescents.

    Science.gov (United States)

    McKay, Michael T; Andretta, James R

    2017-09-01

    Mental well-being is an important indicator of current, but also the future health of adolescents. The 14-item Warwick Edinburgh Mental Well-being Scale (WEMWBS) has been well validated in adults world-wide, but less work has been undertaken to examine the psychometric validity and internal consistency of WEMWBS scores in adolescents. In particular, little research has examined scores on the short 7-item version of the WEMWBS. The present study used two large samples of school children in Scotland and Northern Ireland and found that for both forms of the WEMWBS, scores were psychometrically valid, internally consistent, factor saturated, and measurement invariant by country. Using the WEMWBS full form, males reported significantly higher scores than females, and Northern Irish adolescents reported significantly higher scores than their Scottish counterparts. Last, the lowest overall levels of well-being were observed among Scottish females. Copyright © 2017. Published by Elsevier B.V.

  6. Exergoeconomic comparison of TLC (trilateral Rankine cycle), ORC (organic Rankine cycle) and Kalina cycle using a low grade heat source

    International Nuclear Information System (INIS)

    Yari, M.; Mehr, A.S.; Zare, V.; Mahmoudi, S.M.S.; Rosen, M.A.

    2015-01-01

    Recently, the TLC (trilateral power cycle) has attracted significant interest as it provides better matching between the temperature profiles in the evaporator compared to conventional power cycles. This article investigates the performance of this cycle and compares it with those for the ORC (organic Rankine cycle) and the Kalina cycle, from the viewpoints of thermodynamics and thermoeconomics. A low-grade heat source with a temperature of 120 °C is considered for all the three systems. Parametric studies are performed for the systems for several working fluids in the ORC and TLC. The systems are then optimized for either maximum net output power or minimum product cost, using the EES (engineering equation solver) software. The results for the TLC indicate that an increase in the expander inlet temperature leads to an increase in net output power and a decrease in product cost for this power plant, whereas this is not the case for the ORC system. It is found that, although the TLC can achieve a higher net output power compared with the ORC and Kalina (KCS11 (Kalina cycle system 11)) systems, its product cost is greatly affected by the expander isentropic efficiency. It is also revealed that using n-butane as the working fluid can result in the lowest product cost in the ORC and the TLC. In addition, it is observed that, for both the ORC and Kalina systems, the optimum operating condition for maximum net output power differs from that for minimum product cost. - Highlights: • Exergoeconomic analysis of trilateral Rankine cycle is performed. • The system performance is compared with Organic Rankine and Kalina cycles. • Net power from trilateral Rankine cycle is higher than the other power systems. • Superiority of trilateral cycle depends on its expander isentropic efficiency

  7. AN OBSERVATIONAL CLINICAL STUDY OF ASSESSING THE UTILITY OF PSS (POISON SEVERITY SCORE AND GCS (GLASGOW COMA SCALE SCORING SYSTEMS IN PREDICTING SEVERITY AND CLINICAL OUTCOMES IN OP POISONING

    Directory of Open Access Journals (Sweden)

    S. Chandrasekhar

    2017-05-01

    Full Text Available BACKGROUND Organophosphorus compound poisoning is the most common poisonings in India because of easy availability often requiring ICU care and ventilator support. Clinical research has indicated that respiratory failure is the most important cause of death due to organophosphorus poisoning. It results in respiratory muscle weakness, pulmonary oedema, respiratory depression, increased secretions and bronchospasm. These complications and death can be prevented with timely institution of ventilator support. MATERIALS AND METHODS Hundred consecutive patients admitted with a history of organophosphorus poisoning at Kurnool Medical College, Kurnool, were taken for study after considering the inclusion and exclusion criteria. Detailed history, confirmation of poisoning, examination and other than routine investigations, serum pseudocholinesterase and arterial blood gas analysis was done. The severity and clinical outcomes in OP poisoning is graded by PSS (poison severity score and GCS (Glasgow coma scale scoring systems. RESULTS This study was conducted in 100 patients with male preponderance. Majority of poisoning occurred in 21-30 age group (n=5. Most common compound consumed in our study was methyl parathion and least common was phosphoran. Slightly more than half of the patients consumed less than 50 mL of poison. 21 patients consumed between 50 to 100 mL. Distribution of poison severity score of patients studied showed 45 cases of grade 1 poisoning. 26 cases of grade 2 poisoning, 23 cases of grade 3 poisoning and 6 cases of grade 4 poisoning (death within first 24 hours. Distribution of GCS score of patients studied GCS scores were <10 in 25 patients at admission and 24 patients after 24 hours. GCS scores were ≥10 in 75 patients at admission and 76 patients after 24 hours. Poison severity score is not prognostic, but merely defines severity of OP poisoning at a given time. CONCLUSION Both Glasgow coma scale and poison severity scoring systems

  8. Number theory and modular forms papers in memory of Robert A Rankin

    CERN Document Server

    Ono, Ken

    2003-01-01

    Robert A. Rankin, one of the world's foremost authorities on modular forms and a founding editor of The Ramanujan Journal, died on January 27, 2001, at the age of 85. Rankin had broad interests and contributed fundamental papers in a wide variety of areas within number theory, geometry, analysis, and algebra. To commemorate Rankin's life and work, the editors have collected together 25 papers by several eminent mathematicians reflecting Rankin's extensive range of interests within number theory. Many of these papers reflect Rankin's primary focus in modular forms. It is the editors' fervent hope that mathematicians will be stimulated by these papers and gain a greater appreciation for Rankin's contributions to mathematics. This volume would be an inspiration to students and researchers in the areas of number theory and modular forms.

  9. Eleven Years of Data on the Jefferson Scale of Empathy-Medical Student Version (JSE-S): Proxy Norm Data and Tentative Cutoff Scores.

    Science.gov (United States)

    Hojat, Mohammadreza; Gonnella, Joseph S

    2015-01-01

    This study was designed to provide typical descriptive statistics, score distributions and percentile ranks of the Jefferson Scale of Empathy-Medical Student version (JSE-S) of male and female medical school matriculants to serve as proxy norm data and tentative cutoff scores. The participants were 2,637 students (1,336 women and 1,301 men) who matriculated at Sidney Kimmel (formerly Jefferson) Medical College between 2002 and 2012, and completed the JSE at the beginning of medical school. Information extracted from descriptive statistics, score distributions and percentile ranks for male and female matriculants were used to develop proxy norm data and tentative cutoff scores. The score distributions of the JSE tended to be moderately skewed and platykurtic. Women obtained a significantly higher mean score (116.2 ± 9.7) than men (112.3 ± 10.8) on the JSE-S (t2,635 = 9.9, p norm data. The tentative cutoff score to identify low scorers was ≤ 95 for men and ≤ 100 for women. Our findings provide norm data and cutoff scores for admission decisions under certain conditions and for identifying students in need of enhancing their empathy. © 2015 S. Karger AG, Basel.

  10. Pattern analysis of total item score and item response of the Kessler Screening Scale for Psychological Distress (K6 in a nationally representative sample of US adults

    Directory of Open Access Journals (Sweden)

    Shinichiro Tomitaka

    2017-02-01

    Full Text Available Background Several recent studies have shown that total scores on depressive symptom measures in a general population approximate an exponential pattern except for the lower end of the distribution. Furthermore, we confirmed that the exponential pattern is present for the individual item responses on the Center for Epidemiologic Studies Depression Scale (CES-D. To confirm the reproducibility of such findings, we investigated the total score distribution and item responses of the Kessler Screening Scale for Psychological Distress (K6 in a nationally representative study. Methods Data were drawn from the National Survey of Midlife Development in the United States (MIDUS, which comprises four subsamples: (1 a national random digit dialing (RDD sample, (2 oversamples from five metropolitan areas, (3 siblings of individuals from the RDD sample, and (4 a national RDD sample of twin pairs. K6 items are scored using a 5-point scale: “none of the time,” “a little of the time,” “some of the time,” “most of the time,” and “all of the time.” The pattern of total score distribution and item responses were analyzed using graphical analysis and exponential regression model. Results The total score distributions of the four subsamples exhibited an exponential pattern with similar rate parameters. The item responses of the K6 approximated a linear pattern from “a little of the time” to “all of the time” on log-normal scales, while “none of the time” response was not related to this exponential pattern. Discussion The total score distribution and item responses of the K6 showed exponential patterns, consistent with other depressive symptom scales.

  11. Present status of severe head injured patients with an admission glasgow coma scale score of 3 based on the Japan neurotrauma data bank

    International Nuclear Information System (INIS)

    Uzura, Masahiko

    2011-01-01

    Severe head injured patients presenting with Glasgow Coma Scale (GCS) score of 3 have been hesitated to treat aggressively. We analyzed present status of patients with GCS score of 3 from the Project 2004 in the Japan Neurotrauma Data Bank. Among 1,101 cases registered, 805 cases with GCS score of 8 or less on admission. Of those, 215 cases with GCS score of 3 were classified the survival group (51 cases) and the dead group (164 cases) and compared each group. These results showed that the characteristics associated with favorable outcome including absence of cardiopulmonary arrest, no abnormality of pupil findings, stable condition of respiration and circulation, serum glucose level (less than 184 mg/dl), absence of initial CT findings including skull base fracture, pneumocephalus and subarachnoid hemorrhage, no serious extracranial injures including Injury Severity Scale score of less than 25, critic al care including intracranial pressure monitoring and temperature management. We suggest that it is important to treat brain and systemic problems aggressively in severe head injured patients with GCS score of 3. (author)

  12. Examining the Impact of Unscorable Item Responses on the Validity and Interpretability of MMPI-2/MMPI-2-RF Restructured Clinical (RC) Scale Scores

    Science.gov (United States)

    Dragon, Wendy R.; Ben-Porath, Yossef S.; Handel, Richard W.

    2012-01-01

    This article examined the impact of unscorable item responses on the psychometric validity and practical interpretability of scores on the Restructured Clinical (RC) Scales of the Minnesota Multiphasic Personality Inventory-2/Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2/MMPI-2-RF). In analyses conducted with five…

  13. The Reverse of Social Anxiety Is Not Always the Opposite: The Reverse-Scored Items of the Social Interaction Anxiety Scale Do Not Belong

    Science.gov (United States)

    Rodebaugh, Thomas L.; Woods, Carol M.; Heimberg, Richard G.

    2007-01-01

    Although well-used and empirically supported, the Social Interaction Anxiety Scale (SIAS) has a questionable factor structure and includes reverse-scored items with questionable utility. Here, using samples of undergraduates and a sample of clients with social anxiety disorder, we extend previous work that opened the question of whether the…

  14. Long-Term Stability of Scores on the Wechsler Intelligence Scale for Children-Fourth Edition in Children with Learning Disabilities

    Science.gov (United States)

    Lander, Jenny

    2010-01-01

    The present investigation explored the stability of scores on the Wechsler Intelligence Scale for Children-IV (WISC-IV) over approximately a three-year period. Previous research has suggested that some children with Learning Disabilities (LD) do not demonstrate long-term stability of intelligence. Legally, school districts are no longer required…

  15. U-Pb zircon age for a volcanic suite in the Rankin Inlet Group, Rankin Inlet map area, District of Keewatin, Northwest Territories

    Energy Technology Data Exchange (ETDEWEB)

    Tella, S; Roddick, J C; VanBreemen, O [Geological Survey of Canada, Ottawa, ON (Canada)

    1997-12-31

    U-Pb zircon analyses from a felsic band within dominantly mafic volcanics of the Rankin Inlet Group yields a U-Pb upper concordia intercept age of 2663 {+-} 3 Ma. These supracrustals at Rankin Inlet appear to be 15-20 Ma younger than volcanics of the Kaminak Group in the Tavani area, 70 km to the southwest. The 2.68-2.66 Ga volcanism in the Tavani and Rankin Inlet areas coincided with the last stage of the main phase of magmatism in the Slave Structural Province. (author). 16 refs., 1 tab., 3 figs.

  16. U-Pb zircon age for a volcanic suite in the Rankin Inlet Group, Rankin Inlet map area, District of Keewatin, Northwest Territories

    International Nuclear Information System (INIS)

    Tella, S.; Roddick, J.C.; VanBreemen, O.

    1996-01-01

    U-Pb zircon analyses from a felsic band within dominantly mafic volcanics of the Rankin Inlet Group yields a U-Pb upper concordia intercept age of 2663 ± 3 Ma. These supracrustals at Rankin Inlet appear to be 15-20 Ma younger than volcanics of the Kaminak Group in the Tavani area, 70 km to the southwest. The 2.68-2.66 Ga volcanism in the Tavani and Rankin Inlet areas coincided with the last stage of the main phase of magmatism in the Slave Structural Province. (author). 16 refs., 1 tab., 3 figs

  17. A study of the effect of a visual arts-based program on the scores of Jefferson Scale for Physician Empathy.

    Science.gov (United States)

    Yang, Kuang-Tao; Yang, Jen-Hung

    2013-10-25

    The effect of visual arts interventions on development of empathy has not been quantitatively investigated. A study was conducted on the effect of a visual arts-based program on the scores of the Jefferson Scale for Physician Empathy (JSPE). A total of 110 clerks (n = 92) and first-year postgraduate residents (PGY1s) (n = 18) participating in the program were recruited into this study. The 4-hr program covered the subjects of learning to interpret paintings, interpreting paintings relating to medicine, illness and human suffering, the related-topics of humanitarianism and the other humanities fields and values and meaning. The JSPE was completed at the beginning (pretest) and the end (posttest) of the program. There was no significant difference between the pretest and posttest JSPE scores. The average of the scores for the pretest was lower in the subgroup of PGY1s than the subgroup of clerks (p = 0.0358). An increased but not significantly mean posttest JESPE score was noted for the subgroup of PGY1s. Neither the females nor the males had higher posttest JSPE scores than the pretest scores. Although using a structured visual arts-based program as an intervention may be useful to enhance medical students' empathy, our results failed to show a positive effect on the JSPE Scores for a group of clerks and PGY1s. This suggests that further experimental studies are needed if quantitative evaluation of the effectiveness of visual-arts based programs on empathy is to be investigated.

  18. Predicting Outcome in Subarachnoid Hemorrhage (SAH) Utilizing the Full Outline of UnResponsiveness (FOUR) Score.

    Science.gov (United States)

    Zeiler, F A; Lo, B W Y; Akoth, E; Silvaggio, J; Kaufmann, A M; Teitelbaum, J; West, M

    2017-12-01

    Existing scoring systems for aneurysmal subarachnoid hemorrhage (SAH) patients fail to accurately predict patient outcome. Our goal was to prospectively study the Full Outline of UnResponsiveness (FOUR) score as applied to newly admitted aneurysmal SAH patients. All adult patients presenting to Health Sciences Center in Winnipeg from January 2013 to July 2015 (2.5 year period) with aneurysmal SAH were prospectively enrolled in this study. All patients were followed up to 6 months. FOUR score was calculated upon admission, with repeat calculation at 7 and 14 days. The primary outcomes were: mortality, as well as dichotomized 1- and 6-month Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) values. Sixty-four patients were included, with a mean age of 54.2 years (range 26-85 years). The mean FOUR score upon admission pre- and post-external ventricular drain (EVD) was 10.3 (range 0-16) and 11.1 (range 3-16), respectively. There was a statistically significant association between pre-EVD FOUR score (total, eye, respiratory and motor sub-scores) with mortality, 1-month GOS, and 6-month GOS/mRS (p FOUR scores were associated with mortality, 1-month GOS/mRS, and 6-month GOS/mRS (p FOUR scores were associated with 6-month GOS (p FOUR score was associated with the development of clinical vasospasm (p FOUR score at admission and day 7 post-SAH is associated with mortality, 1-month GOS/mRS, and 6-month GOS/mRS. The FOUR score at day 14 post-SAH is associated with 6-month GOS. The brainstem sub-score was not associated with 1- or 6-month primary outcomes.

  19. Standardized Total Average Toxicity Score: A Scale- and Grade-Independent Measure of Late Radiotherapy Toxicity to Facilitate Pooling of Data From Different Studies

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Gillian C., E-mail: gillbarnett@doctors.org.uk [University of Cambridge Department of Oncology, Oncology Centre, Cambridge (United Kingdom); Cancer Research-UK Centre for Genetic Epidemiology and Department of Oncology, Strangeways Research Laboratories, Cambridge (United Kingdom); West, Catharine M.L. [School of Cancer and Enabling Sciences, Manchester Academic Health Science Centre, University of Manchester, Christie Hospital, Manchester (United Kingdom); Coles, Charlotte E. [University of Cambridge Department of Oncology, Oncology Centre, Cambridge (United Kingdom); Pharoah, Paul D.P. [Cancer Research-UK Centre for Genetic Epidemiology and Department of Oncology, Strangeways Research Laboratories, Cambridge (United Kingdom); Talbot, Christopher J. [Department of Genetics, University of Leicester, Leicester (United Kingdom); Elliott, Rebecca M. [School of Cancer and Enabling Sciences, Manchester Academic Health Science Centre, University of Manchester, Christie Hospital, Manchester (United Kingdom); Tanteles, George A. [Department of Clinical Genetics, University Hospitals of Leicester, Leicester (United Kingdom); Symonds, R. Paul [Department of Cancer Studies and Molecular Medicine, University Hospitals of Leicester, Leicester (United Kingdom); Wilkinson, Jennifer S. [University of Cambridge Department of Oncology, Oncology Centre, Cambridge (United Kingdom); Dunning, Alison M. [Cancer Research-UK Centre for Genetic Epidemiology and Department of Oncology, Strangeways Research Laboratories, Cambridge (United Kingdom); Burnet, Neil G. [University of Cambridge Department of Oncology, Oncology Centre, Cambridge (United Kingdom); Bentzen, Soren M. [University of Wisconsin, School of Medicine and Public Health, Department of Human Oncology, Madison, WI (United States)

    2012-03-01

    Purpose: The search for clinical and biologic biomarkers associated with late radiotherapy toxicity is hindered by the use of multiple and different endpoints from a variety of scoring systems, hampering comparisons across studies and pooling of data. We propose a novel metric, the Standardized Total Average Toxicity (STAT) score, to try to overcome these difficulties. Methods and Materials: STAT scores were derived for 1010 patients from the Cambridge breast intensity-modulated radiotherapy trial and 493 women from University Hospitals of Leicester. The sensitivity of the STAT score to detect differences between patient groups, stratified by factors known to influence late toxicity, was compared with that of individual endpoints. Analysis of residuals was used to quantify the effect of these covariates. Results: In the Cambridge cohort, STAT scores detected differences (p < 0.00005) between patients attributable to breast volume, surgical specimen weight, dosimetry, acute toxicity, radiation boost to tumor bed, postoperative infection, and smoking (p < 0.0002), with no loss of sensitivity over individual toxicity endpoints. Diabetes (p = 0.017), poor postoperative surgical cosmesis (p = 0.0036), use of chemotherapy (p = 0.0054), and increasing age (p = 0.041) were also associated with increased STAT score. When the Cambridge and Leicester datasets were combined, STAT was associated with smoking status (p < 0.00005), diabetes (p = 0.041), chemotherapy (p = 0.0008), and radiotherapy boost (p = 0.0001). STAT was independent of the toxicity scale used and was able to deal with missing data. There were correlations between residuals of the STAT score obtained using different toxicity scales (r > 0.86, p < 0.00005 for both datasets). Conclusions: The STAT score may be used to facilitate the analysis of overall late radiation toxicity, from multiple trials or centers, in studies of possible genetic and nongenetic determinants of radiotherapy toxicity.

  20. Nuclear alkali metal Rankine power systems for space applications

    International Nuclear Information System (INIS)

    Moyers, J.C.; Holcomb, R.S.

    1986-08-01

    Nucler power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper

  1. Nuclear alkali metal Rankine power systems for space applications

    International Nuclear Information System (INIS)

    Moyers, J.C.; Holcomb, R.S.

    1986-01-01

    Nuclear power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper

  2. Status of the organic Rankine cycle for space applications

    Science.gov (United States)

    Bland, T. J.; Lacey, P. D.; Sorensen, G. L.

    The Organic Rankine Cycle (ORC) has been under continuous development and evaluation since the 1960s for both terrestrial and space power applications. Recent activities (Bland et al, 1987) have focused primarily on the Space Station's solar dynamic power system and Dynamic Isotope Power Systems (DIPS) applications. This paper addresses ORC-DIPS system level trade studies conducted during the past year and a half. Two companion papers (Bland and Pearson) present more detailed data on specific ORC-DIPS technology issues and testing conducted during the same period.

  3. Minnesota multiphasic personality inventory-2 restructured form (MMPI-2-RF) scale score differences in bariatric surgery candidates diagnosed with binge eating disorder versus BMI-matched controls.

    Science.gov (United States)

    Marek, Ryan J; Ben-Porath, Yossef S; Ashton, Kathleen; Heinberg, Leslie J

    2014-04-01

    Binge Eating Disorder (BED) is among the most common psychiatric disorders in bariatric surgery candidates. The Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF) is a broadband, psychological test that includes measures of emotional and behavioral dysfunction, which have been associated with BED behaviors in bariatric surgery candidates; however these studies have lacked appropriate controls. In the current study, we compared MMPI-2-RF scale scores of bariatric surgery patients diagnosed with BED (BED+) with BMI-matched controls without BED (BED-). Three-hundred and seven BED+ participants (72.64% female and 67.87% Caucasian; mean BMI of 51.36 kg/m(2) [SD = 11.94]) were drawn from a large, database (N = 1304). Three-hundred and seven BED- participants were matched on BMI and demographics (72.64% female, 68.63% Caucasian, and mean BMI of 51.30 kg/m(2) [SD = 11.70]). The BED+ group scored significantly higher on measures of Demoralization, Low Positive Emotions, and Dysfunctional Negative Emotions and scored lower on measures of Antisocial Behaviors, reflecting behavioral constraint. Optimal T-Score cutoffs were below the traditional 65 T score for several MMPI-2-RF scales. MMPI-2-RF externalizing measures also added incrementally to differentiating between the groups beyond the Binge Eating Scale (BES). BED+ individuals produced greater elevations on a number of MMPI-2-RF internalizing scales and externalizing scales. Use of the test in conjunction with a clinical interview and other self-report data can further aid the clinician in guiding patients to appropriate treatment to optimize outcome. Copyright © 2013 Wiley Periodicals, Inc.

  4. Computed tomography and magnetic resonance imaging of mild head injury - is it appropriate to classify patients with glasgow coma scale score of 13 to 15 as 'mild injury'?

    International Nuclear Information System (INIS)

    Uchino, Y.; Saeki, N.; Yamaura, A.; Okimura, Y.; Tanaka, M.

    2001-01-01

    Objective. The purpose of this study is to examine the relation between Glasgow coma scale (GCS) score and findings on computed tomography (CT) and magnetic resonance (MR) imaging of patients with mild head injury presenting GCS Scores between 13 and 15. Methods. Data were collected from all consecutive patients with mild head injury who were referred to our hospital between July 1 and October 31, 1999. All patients were recommended to undergo CT and MR imaging examinations. Patients younger than 14 years of age were excluded. Results. Ninety patients were recruited into this study. CT scans were obtained in 88 patients and MR imaging were obtained in 65 patients. Of those 90 patients, 2 patients scored 13 points, 5 scored 14 points and 83 (92.2 %) 15 points. Patients with GCS score of 13 points demonstrated parenchymal lesions an both CT and MR imaging. Those with 14 points revealed absence of parenchymal abnormality an CT, but presence of parenchymal lesions an MR imaging. Patients in advanced age (chi square test, p < 0.0001), and those with amnesia (p = 0005, not significant), although scoring 15 points, revealed a tendency to abnormal intracranial lesions on CT scans. Conclusion. It is doubtful whether patients with GCS score 13 should be included in the mild head injury category, due to obvious brain damage on CT scans. MR imaging should be performed on patients with GCS score 14, since the parenchymal lesions are not clearly demonstrated an CT scans. Even if patients scored GCS 15, patients which amnesia or of advanced age should undergo CT scans at minimum, and MR imaging when available. (author)

  5. The responsiveness of the International Prostate Symptom Score, Incontinence Impact Questionnaire-7 and Depression, Anxiety and Stress Scale-21 in patients with lower urinary tract symptoms.

    Science.gov (United States)

    Choi, Edmond P H; Chin, Weng Yee; Lam, Cindy L K; Wan, Eric Y F

    2015-08-01

    To examine the responsiveness of a combined symptom severity and health-related quality of life measure, condition-specific health-related quality of life measure and mental health measure in patients with lower urinary tract symptoms. To establish the responsiveness of measures that accurately capture the change in health status of patients is crucial before any longitudinal studies can be appropriately planned and evaluated. Prospective longitudinal observational study. 402 patients were surveyed at baseline and 1-year using the International Prostate Symptom Score, the Incontinence Impact Questionnaire-7 and Depression, Anxiety and Stress Scales-21. The internal and external responsiveness were assessed. Surveys were conducted from March 2013-July 2014. In participants with improvements, the internal responsiveness for detecting positive changes was satisfactory in males and females for all scales, expect for the Depression subscale. The health-related quality of life question of the International Prostate Symptom Score was more externally responsive than the Incontinence Impact Questionnaire-7. The International Prostate Symptom Score and Anxiety and Stress subscales were more responsive in males than in females. The symptom questions of the International Prostate Symptom Score and Anxiety and Stress subscales were not externally responsive in females. The health-related quality of life question of the International Prostate Symptom Score outperformed the Incontinence Impact Questionnaire-7 in both males and females, in terms of external responsiveness. © 2015 John Wiley & Sons Ltd.

  6. Altheim geothermal plant. Power generation by means of an ORC turbogenerator; Geothermieanlagen Altheim. Stromerzeugung mittels Organic-Rankine-Cycle Turbogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Pernecker, G [Marktgemeindeamt Altheim (Austria)

    1997-12-01

    The report describes the project of the Austrian market town of Altheim to generate electricity by means of an ORC turbogenerator using low-temperature thermal water. The project is to improve the technical and economic situation of the existing industrial-scale geothermal project. (orig.) [Deutsch] Der Bericht beschreibt das Vorhaben der Marktgemeinde Altheim in Oberoesterreich, Strom mittels eines Organic-Rankine-Cycle-Turbogenerators unter Verwendung niedrig temperierten Thermalwassers zu produzieren. Ziel bzw. der Zweck des Projektes ist es, die technische und wirtschaftliche Situation der bestehenden Grossthermieanlage zu verbessern. (orig.)

  7. Optimization of MRI-based scoring scales of brain injury severity in children with unilateral cerebral palsy

    International Nuclear Information System (INIS)

    Pagnozzi, Alex M.; Fiori, Simona; Boyd, Roslyn N.; Guzzetta, Andrea; Doecke, James; Rose, Stephen; Dowson, Nicholas; Gal, Yaniv

    2016-01-01

    Several scoring systems for measuring brain injury severity have been developed to standardize the classification of MRI results, which allows for the prediction of functional outcomes to help plan effective interventions for children with cerebral palsy. The aim of this study is to use statistical techniques to optimize the clinical utility of a recently proposed template-based scoring method by weighting individual anatomical scores of injury, while maintaining its simplicity by retaining only a subset of scored anatomical regions. Seventy-six children with unilateral cerebral palsy were evaluated in terms of upper limb motor function using the Assisting Hand Assessment measure and injuries visible on MRI using a semiquantitative approach. This cohort included 52 children with periventricular white matter injury and 24 with cortical and deep gray matter injuries. A subset of the template-derived cerebral regions was selected using a data-driven region selection algorithm. Linear regression was performed using this subset, with interaction effects excluded. Linear regression improved multiple correlations between MRI-based and Assisting Hand Assessment scores for both periventricular white matter (R squared increased to 0.45 from 0, P < 0.0001) and cortical and deep gray matter (0.84 from 0.44, P < 0.0001) cohorts. In both cohorts, the data-driven approach retained fewer than 8 of the 40 template-derived anatomical regions. The equal or better prediction of the clinically meaningful Assisting Hand Assessment measure using fewer anatomical regions highlights the potential of these developments to enable enhanced quantification of injury and prediction of patient motor outcome, while maintaining the clinical expediency of the scoring approach. (orig.)

  8. Optimization of MRI-based scoring scales of brain injury severity in children with unilateral cerebral palsy.

    Science.gov (United States)

    Pagnozzi, Alex M; Fiori, Simona; Boyd, Roslyn N; Guzzetta, Andrea; Doecke, James; Gal, Yaniv; Rose, Stephen; Dowson, Nicholas

    2016-02-01

    Several scoring systems for measuring brain injury severity have been developed to standardize the classification of MRI results, which allows for the prediction of functional outcomes to help plan effective interventions for children with cerebral palsy. The aim of this study is to use statistical techniques to optimize the clinical utility of a recently proposed template-based scoring method by weighting individual anatomical scores of injury, while maintaining its simplicity by retaining only a subset of scored anatomical regions. Seventy-six children with unilateral cerebral palsy were evaluated in terms of upper limb motor function using the Assisting Hand Assessment measure and injuries visible on MRI using a semiquantitative approach. This cohort included 52 children with periventricular white matter injury and 24 with cortical and deep gray matter injuries. A subset of the template-derived cerebral regions was selected using a data-driven region selection algorithm. Linear regression was performed using this subset, with interaction effects excluded. Linear regression improved multiple correlations between MRI-based and Assisting Hand Assessment scores for both periventricular white matter (R squared increased to 0.45 from 0, P < 0.0001) and cortical and deep gray matter (0.84 from 0.44, P < 0.0001) cohorts. In both cohorts, the data-driven approach retained fewer than 8 of the 40 template-derived anatomical regions. The equal or better prediction of the clinically meaningful Assisting Hand Assessment measure using fewer anatomical regions highlights the potential of these developments to enable enhanced quantification of injury and prediction of patient motor outcome, while maintaining the clinical expediency of the scoring approach.

  9. Optimization of MRI-based scoring scales of brain injury severity in children with unilateral cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Pagnozzi, Alex M. [Royal Brisbane and Women' s Hospital, CSIRO Digital Productivity and Services Flagship, The Australian e-Health Research Centre, Herston, QLD (Australia); The University of Queensland, School of Medicine, Brisbane (Australia); Fiori, Simona [Stella Maris Scientific Institute, Pisa (Italy); Boyd, Roslyn N. [The University of Queensland, Queensland Cerebral Palsy and Rehabilitation Research Centre, School of Medicine, Brisbane (Australia); Guzzetta, Andrea [Stella Maris Scientific Institute, Pisa (Italy); University of Pisa, Department of Clinical and Experimental Medicine, Pisa (Italy); Doecke, James; Rose, Stephen; Dowson, Nicholas [Royal Brisbane and Women' s Hospital, CSIRO Digital Productivity and Services Flagship, The Australian e-Health Research Centre, Herston, QLD (Australia); Gal, Yaniv [The University of Queensland, Centre for Medical Diagnostic Technologies in Queensland, Brisbane (Australia)

    2016-02-15

    Several scoring systems for measuring brain injury severity have been developed to standardize the classification of MRI results, which allows for the prediction of functional outcomes to help plan effective interventions for children with cerebral palsy. The aim of this study is to use statistical techniques to optimize the clinical utility of a recently proposed template-based scoring method by weighting individual anatomical scores of injury, while maintaining its simplicity by retaining only a subset of scored anatomical regions. Seventy-six children with unilateral cerebral palsy were evaluated in terms of upper limb motor function using the Assisting Hand Assessment measure and injuries visible on MRI using a semiquantitative approach. This cohort included 52 children with periventricular white matter injury and 24 with cortical and deep gray matter injuries. A subset of the template-derived cerebral regions was selected using a data-driven region selection algorithm. Linear regression was performed using this subset, with interaction effects excluded. Linear regression improved multiple correlations between MRI-based and Assisting Hand Assessment scores for both periventricular white matter (R squared increased to 0.45 from 0, P < 0.0001) and cortical and deep gray matter (0.84 from 0.44, P < 0.0001) cohorts. In both cohorts, the data-driven approach retained fewer than 8 of the 40 template-derived anatomical regions. The equal or better prediction of the clinically meaningful Assisting Hand Assessment measure using fewer anatomical regions highlights the potential of these developments to enable enhanced quantification of injury and prediction of patient motor outcome, while maintaining the clinical expediency of the scoring approach. (orig.)

  10. A higher score on the Aging Males' Symptoms scale is associated with insulin resistance in middle-aged men.

    Science.gov (United States)

    Hamanoue, Nobuya; Tanabe, Makito; Tanaka, Tomoko; Akehi, Yuko; Murakami, Junji; Nomiyama, Takashi; Yanase, Toshihiko

    2017-05-30

    An age-associated androgen decrease and its pathological conditions are defined as late-onset hypogonadism (LOH). Among the various symptoms associated with LOH, a visceral fat increase is strongly associated with relatively low levels of testosterone. However, few studies have investigated the relationship between the Aging Males' Symptoms (AMS) scores and metabolic abnormalities. Thus, we aimed to clarify this relationship by investigating the relationship between AMS scores and various markers in blood. During routine health examinations in 241 middle-aged males (52.7±7.5 years of age, mean±SD), 150 males (62.2%) displayed higher AMS values than normal. No statistical association was observed between total AMS scores and any testosterone value. All mental, physical and sexual AMS subscales were significantly positively correlated with insulin levels and HOMA-IR. Only sexual subscale scores were significantly inversely associated with free or bioavailable testosterone level. Males with insulin resistance (HOMA-IR≥2.5) demonstrated significantly higher AMS scores than those with normal insulin sensitivity (HOMA-IRinsulin and HOMA-IR values. Interestingly, univariate and multivariate analyses revealed that HOMA-IR≥2.5 was a significant predictor for detection of moderately severe AMS values (AMS≥37), whereas AMS≥37 was not a predictor of metabolic syndrome by International Diabetes Federation (IDF) criterion. In conclusion, almost 60% of healthy male subjects displayed abnormal AMS scores. AMS values were not associated with testosterone values but rather were related to insulin resistance, particularly in subjects with moderately severe AMS values. Insulin resistance-related general unwellness might be reflected by AMS values.

  11. Integrated biomass pyrolysis with organic Rankine cycle for power generation

    Science.gov (United States)

    Nur, T. B.; Syahputra, A. W.

    2018-02-01

    The growing interest on Organic Rankine Cycle (ORC) application to produce electricity by utilizing biomass energy sources are increasingly due to its successfully used to generate power from waste heat available in industrial processes. Biomass pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. In the application, biomass pyrolysis can be divided into three main categories; slow, fast and flash pyrolysis mainly aiming at maximizing the products of bio-oil or biochar. The temperature of synthesis gas generated during processes can be used for Organic Rankine Cycle to generate power. The heat from synthesis gas during pyrolysis processes was transfer by thermal oil heater to evaporate ORC working fluid in the evaporator unit. In this study, the potential of the palm oil empty fruit bunch, palm oil shell, and tree bark have been used as fuel from biomass to generate electricity by integrated with ORC. The Syltherm-XLT thermal oil was used as the heat carrier from combustion burner, while R245fa was used as the working fluid for ORC system. Through Aspen Plus, this study analyses the influences on performance of main thermodynamic parameters, showing the possibilities of reaching an optimum performance for different working conditions that are characteristics of different design parameters.

  12. Solar thermal organic rankine cycle for micro-generation

    Science.gov (United States)

    Alkahli, N. A.; Abdullah, H.; Darus, A. N.; Jalaludin, A. F.

    2012-06-01

    The conceptual design of an Organic Rankine Cycle (ORC) driven by solar thermal energy is developed for the decentralized production of electricity of up to 50 kW. Conventional Rankine Cycle uses water as the working fluid whereas ORC uses organic compound as the working fluid and it is particularly suitable for low temperature applications. The ORC and the solar collector will be sized according to the solar flux distribution in the Republic of Yemen for the required power output of 50 kW. This will be a micro power generation system that consists of two cycles, the solar thermal cycle that harness solar energy and the power cycle, which is the ORC that generates electricity. As for the solar thermal cycle, heat transfer fluid (HTF) circulates the cycle while absorbing thermal energy from the sun through a parabolic trough collector and then storing it in a thermal storage to increase system efficiency and maintains system operation during low radiation. The heat is then transferred to the organic fluid in the ORC via a heat exchanger. The organic fluids to be used and analyzed in the ORC are hydrocarbons R600a and R290.

  13. New scoring methodology improves the sensitivity of the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) in clinical trials.

    Science.gov (United States)

    Verma, Nishant; Beretvas, S Natasha; Pascual, Belen; Masdeu, Joseph C; Markey, Mia K

    2015-11-12

    As currently used, the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) has low sensitivity for measuring Alzheimer's disease progression in clinical trials. A major reason behind the low sensitivity is its sub-optimal scoring methodology, which can be improved to obtain better sensitivity. Using item response theory, we developed a new scoring methodology (ADAS-CogIRT) for the ADAS-Cog, which addresses several major limitations of the current scoring methodology. The sensitivity of the ADAS-CogIRT methodology was evaluated using clinical trial simulations as well as a negative clinical trial, which had shown an evidence of a treatment effect. The ADAS-Cog was found to measure impairment in three cognitive domains of memory, language, and praxis. The ADAS-CogIRT methodology required significantly fewer patients and shorter trial durations as compared to the current scoring methodology when both were evaluated in simulated clinical trials. When validated on data from a real clinical trial, the ADAS-CogIRT methodology had higher sensitivity than the current scoring methodology in detecting the treatment effect. The proposed scoring methodology significantly improves the sensitivity of the ADAS-Cog in measuring progression of cognitive impairment in clinical trials focused in the mild-to-moderate Alzheimer's disease stage. This provides a boost to the efficiency of clinical trials requiring fewer patients and shorter durations for investigating disease-modifying treatments.

  14. Optimal design of compact organic Rankine cycle units for domestic solar applications

    Directory of Open Access Journals (Sweden)

    Barbazza Luca

    2014-01-01

    Full Text Available Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design criteria, i. e., compactness, high performance and safe operation, are targeted by adopting a multi-objective optimization approach modeled with the genetic algorithm. Design-point thermodynamic variables, e. g., evaporating pressure, the working fluid, minimum allowable temperature differences, and the equipment geometry, are the decision variables. Flat plate heat exchangers with herringbone corrugations are selected as heat transfer equipment for the preheater, the evaporator and the condenser. The results unveil the hyperbolic trend binding the net power output to the heat exchanger compactness. Findings also suggest that the evaporator and condenser minimum allowable temperature differences have the largest impact on the system volume and on the cycle performances. Among the fluids considered, the results indicate that R1234yf and R1234ze are the best working fluid candidates. Using flat plate solar collectors (hot water temperature equal to 75 °C, R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm3, whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal to 120 °C. In such case the thermal efficiency is around 6.9%, and the heat exchanger volume varies from 6.0 to 18.0 dm3.

  15. Analysis and assessment of a new organic Rankine based heat engine system with/without cogeneration

    International Nuclear Information System (INIS)

    Hogerwaard, Janette; Dincer, Ibrahim; Zamfirescu, Calin

    2013-01-01

    A low-temperature heat driven heat engine is proposed as a cost-effective system for power and heat production for small scale applications. The external heat source allows flexibility in the design; the system may be coupled with various available renewable sources including biomass/biofuel/biogas combustion, geothermal heat, concentrated solar radiation, and industrial waste heat, by selecting appropriate off-the-shelf components from the HVAC (heating, ventilation, and air conditioning), refrigeration, and automotive industries for use in an ORC (organic Rankine cycle). A theoretical analysis and an experimental study are carried out for an ORC with R134a as the working fluid, utilizing a low-temperature heat source (T source < 150 °C), with focus on the expansion and boiling processes. The complete ORC model is comprised of models for the expander, working fluid pump, boiler, and condenser. Thermodynamic and heat transfer models are developed to calculate the local and averaged heat transfer coefficient of the working fluid throughout the boiling process, based on the geometry of the selected heat exchanger. Data collected for the experimental ORC test bench are used to validate the expander and boiler models. A case study is performed for the proposed ORC, for cogeneration of power and heat in a residential application. The results of the case study analysis for the proposed ORC system indicate a cycle efficiency of 0.05, exergy efficiency of 0.17, and energy and exergy cogeneration efficiency of 0.87, and 0.35, respectively. - Highlights: • Development and investigation of a scroll based Rankine heat engine operating with R134a. • Thermodynamic analyses of the system and its components. • Heat transfer analyses of boiler and condenser. • Dynamic analysis of expander. • Model validation through performed experiments on an ORC test bench

  16. Clinical study on HAT and SEDAN score scales and related risk factors for predicting hemorrhagic transformation following thrombolysis in acute ischemic stroke

    Directory of Open Access Journals (Sweden)

    Heng WEI

    2015-03-01

    Full Text Available Objective To investigate the value of HAT and SEDAN score scales in predicting hemorrhagic transformation (HT following the recombinant tissue-type plasminogen activator (rt-PA intravenous thrombolysis in acute ischemic stroke patients and risk factors affecting HT.  Methods A total of 143 patients with acute ischemic stroke underwent rt-PA intravenous thrombolysis within 4.50 h of onset and their clinical data were collected. According to head CT after thrombolysis, patients were divided into HT group (18 cases and non-HT group (125 cases. Single factor analysis was used to assess differences in HAT and SEDAN score scales and related risk factors of ischemic stroke in 2 groups, and further Logistic regression analysis was used to investigate independent predictors of HT. Receiver operating characteristic (ROC curve was used to evaluate the sensitivity and specificity of HAT and SEDAN score scales in predicting HT.  Results Univariate Logistic regression analysis showed that history of atrial fibrillation (AF, admission systolic blood pressure (SBP, admission blood glucose level, early low density of head CT, thrombolytic time window, National Institute of Health Stroke Scale (NIHSS, HAT and SEDAN scores were all risk factors for HT after thrombolysis (P < 0.05, for all. Multivariate Logistic regression analysis showed that history of AF (OR = 1.677, 95% CI: 1.332-2.111; P = 0.000, admission SBP (OR = 1.102, 95% CI: 1.009-1.204; P = 0.031, admission blood glucose level (OR = 1.870, 95% CI: 1.119-3.125; P = 0.017, thrombolysis time window (OR = 1.030, 95%CI: 1.009-1.052; P = 0.005, NIHSS score (OR = 1.574, 95%CI: 1.186-2.090; P = 0.002, HAT score (OR = 2.515, 95%CI: 1.273-4.970;P = 0.008 and SEDAN score (OR = 2.413, 95%CI: 1.123-5.185; P = 0.024 were risk factors for HT after thrombolysis. ROC curve analysis showed that HAT score could predict HT with 94.40% sensitivity and 41.60% specificity, and area under curve (AUC was 0.70. SEDAN

  17. Thai venous stroke prognostic score: TV-SPSS.

    Science.gov (United States)

    Poungvarin, Niphon; Prayoonwiwat, Naraporn; Ratanakorn, Disya; Towanabut, Somchai; Tantirittisak, Tassanee; Suwanwela, Nijasri; Phanthumchinda, Kamman; Tiamkoa, Somsak; Chankrachang, Siwaporn; Nidhinandana, Samart; Laptikultham, Somsak; Limsoontarakul, Sansern; Udomphanthuruk, Suthipol

    2009-11-01

    Prognosis of cerebral venous sinus thrombosis (CVST) has never been studied in Thailand. A simple prognostic score to predict poor prognosis of CVST has also never been reported. The authors are aiming to establish a simple and reliable prognostic score for this condition. The medical records of CVST patients from eight neurological training centers in Thailand who received between April 1993 and September 2005 were reviewed as part of this retrospective study. Clinical features included headache, seizure, stroke risk factors, Glasgow coma scale (GCS), blood pressure on arrival, papilledema, hemiparesis, meningeal irritation sign, location of occluded venous sinuses, hemorrhagic infarction, cerebrospinal fluid opening pressure, treatment options, length of stay, and other complications were analyzed to determine the outcome using modified Rankin scale (mRS). Poor prognosis (defined as mRS of 3-6) was determined on the discharge date. One hundred ninety four patients' records, 127 females (65.5%) and mean age of 36.6 +/- 14.4 years, were analyzed Fifty-one patients (26.3%) were in the poor outcome group (mRS 3-6). Overall mortality was 8.4%. Univariate analysis and then multivariate analysis using SPSS version 11.5 revealed only four statistically significant predictors influencing outcome of CVST They were underlying malignancy, low GCS, presence of hemorrhagic infarction (for poor outcome), and involvement of lateral sinus (for good outcome). Thai venous stroke prognostic score (TV-SPSS) was derived from these four factors using a multiple logistic model. A simple and pragmatic prognostic score for CVST outcome has been developed with high sensitivity (93%), yet low specificity (33%). The next study should focus on the validation of this score in other prospective populations.

  18. A Study of the Effect of a Child's Physical Attractiveness upon Verbal Scoring of the Wechsler Intelligence Scale for Children (Revised) and upon Personality Attributions

    OpenAIRE

    Wheeler, Paula Theisler

    1985-01-01

    The purpose of this research was to investigate possible examiner bias in scoring the Verbal subtests of the Wechsler Intelligence Scale for Children (Revised) due to the level of facial attractiveness of the child. Sex of the child and sex of the research subject were also included as independent variables. No main effect for attractiveness or sex x attractiveness interactions were found. Thus, little evidence emerged to suggest attractiveness stereotyping effects in an intelligence testing ...

  19. Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) processing speed scores as measures of noncredible responding: The third generation of embedded performance validity indicators.

    Science.gov (United States)

    Erdodi, Laszlo A; Abeare, Christopher A; Lichtenstein, Jonathan D; Tyson, Bradley T; Kucharski, Brittany; Zuccato, Brandon G; Roth, Robert M

    2017-02-01

    Research suggests that select processing speed measures can also serve as embedded validity indicators (EVIs). The present study examined the diagnostic utility of Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) subtests as EVIs in a mixed clinical sample of 205 patients medically referred for neuropsychological assessment (53.3% female, mean age = 45.1). Classification accuracy was calculated against 3 composite measures of performance validity as criterion variables. A PSI ≤79 produced a good combination of sensitivity (.23-.56) and specificity (.92-.98). A Coding scaled score ≤5 resulted in good specificity (.94-1.00), but low and variable sensitivity (.04-.28). A Symbol Search scaled score ≤6 achieved a good balance between sensitivity (.38-.64) and specificity (.88-.93). A Coding-Symbol Search scaled score difference ≥5 produced adequate specificity (.89-.91) but consistently low sensitivity (.08-.12). A 2-tailed cutoff on the Coding/Symbol Search raw score ratio (≤1.41 or ≥3.57) produced acceptable specificity (.87-.93), but low sensitivity (.15-.24). Failing ≥2 of these EVIs produced variable specificity (.81-.93) and sensitivity (.31-.59). Failing ≥3 of these EVIs stabilized specificity (.89-.94) at a small cost to sensitivity (.23-.53). Results suggest that processing speed based EVIs have the potential to provide a cost-effective and expedient method for evaluating the validity of cognitive data. Given their generally low and variable sensitivity, however, they should not be used in isolation to determine the credibility of a given response set. They also produced unacceptably high rates of false positive errors in patients with moderate-to-severe head injury. Combining evidence from multiple EVIs has the potential to improve overall classification accuracy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  20. A Comparison of Low IQ Scores from the Reynolds Intellectual Assessment Scales and the Wechsler Adult Intelligence Scale--Third Edition

    Science.gov (United States)

    Umphress, Thomas B.

    2008-01-01

    Twenty people with suspected intellectual disability took the Reynolds Intellectual Assessment Scales (RIAS; C. R. Reynolds & R. W. Kamphaus, 1998) and the Wechsler Adult Intelligence Scale--3rd Edition (WAIS-III; D. Wechsler, 1997) to see if the 2 IQ tests produced comparable results. A t test showed that the RIAS Composite Intelligence Index…

  1. Integration between a thermophotovoltaic generator and an Organic Rankine Cycle

    International Nuclear Information System (INIS)

    De Pascale, Andrea; Ferrari, Claudio; Melino, Francesco; Morini, Mirko; Pinelli, Michele

    2012-01-01

    Highlights: ► A new energy system comprising a Thermo-Photo-Voltaic and Organic Rankine Cycle. ► An analytical model to calculate the performance of the system is introduced. ► The system shows promising results in terms of CHP performance. -- Abstract: The constant increase in energy need and the growing attention to the related environmental impact have given a boost to the development of new strategies in order to reduce the primary energy consumption and to improve its utilization. One of the possible strategies for achieving this aim is Combined Heat and Power (CHP) specially if coupled with the concept of on-site generation (also known as distributed generation). These approaches allow the reduction of fuel consumption and pollutant emissions and the increase of security in energy supply. This paper introduces the Thermophotovoltaic Organic Rankine Cycle Integrated System (TORCIS), an energy system integrating a ThermoPhotoVoltaic generator (TPV) and an Organic Rankine Cycle (ORC). This study represents the start-up of a research program which involves three research teams from IMEM – National Research Council, ENDIF – University of Ferrara and DIEM – University of Bologna. The aim of this research is the complete definition and the pre-prototyping characterization of this system covering all the unresolved issues in this field. More specifically, TPV is a system to convert the radiation emitted from an artificial heat source (i.e. the combustion of fuel) into electrical energy by the use of photovoltaic cells. In this system, the produced electrical power is strictly connected to the thermal one as their ratio is almost constant and cannot be changed without severe loss in performance. The coupling between TPV and ORC allows this limitation to be overcome by the realization of a CHP system which can be regulated with a large degree of freedom changing the ratio between the produced electrical and thermal power. In this study a thermodynamic

  2. Conversion Between Mini-Mental State Examination, Montreal Cognitive Assessment, and Dementia Rating Scale-2 Scores in Parkinson’s Disease

    Science.gov (United States)

    van Steenoven, Inger; Aarsland, Dag; Hurtig, Howard; Chen-Plotkin, Alice; Duda, John E.; Rick, Jacqueline; Chahine, Lama M.; Dahodwala, Nabila; Trojanowski, John Q.; Roalf, David R.; Moberg, Paul J.; Weintraub, Daniel

    2015-01-01

    Cognitive impairment is one of the earliest, most common, and most disabling non-motor symptoms in Parkinson’s disease (PD). Thus, routine screening of global cognitive abilities is important for the optimal management of PD patients. Few global cognitive screening instruments have been developed for or validated in PD patients. The Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Dementia Rating Scale-2 (DRS-2) have been used extensively for cognitive screening in both clinical and research settings. Determining how to convert the scores between instruments would facilitate the longitudinal assessment of cognition in clinical settings and the comparison and synthesis of cognitive data in multicenter and longitudinal cohort studies. The primary aim of this study was to apply a simple and reliable algorithm for the conversion of MoCA to MMSE scores in PD patients. A secondary aim was to apply this algorithm for the conversion of DRS-2 to both MMSE and MoCA scores. The cognitive performance of a convenience sample of 360 patients with idiopathic PD was assessed by at least two of these cognitive screening instruments. We then developed conversion scores between the MMSE, MoCA, and DRS-2 using equipercentile equating and log-linear smoothing. The conversion score tables reported here enable direct and easy comparison of three routinely used cognitive screening assessments in PD patients. PMID:25381961

  3. Effect of image compression and scaling on automated scoring of immunohistochemical stainings and segmentation of tumor epithelium

    Directory of Open Access Journals (Sweden)

    Konsti Juho

    2012-03-01

    Full Text Available Abstract Background Digital whole-slide scanning of tissue specimens produces large images demanding increasing storing capacity. To reduce the need of extensive data storage systems image files can be compressed and scaled down. The aim of this article is to study the effect of different levels of image compression and scaling on automated image analysis of immunohistochemical (IHC stainings and automated tumor segmentation. Methods Two tissue microarray (TMA slides containing 800 samples of breast cancer tissue immunostained against Ki-67 protein and two TMA slides containing 144 samples of colorectal cancer immunostained against EGFR were digitized with a whole-slide scanner. The TMA images were JPEG2000 wavelet compressed with four compression ratios: lossless, and 1:12, 1:25 and 1:50 lossy compression. Each of the compressed breast cancer images was furthermore scaled down either to 1:1, 1:2, 1:4, 1:8, 1:16, 1:32, 1:64 or 1:128. Breast cancer images were analyzed using an algorithm that quantitates the extent of staining in Ki-67 immunostained images, and EGFR immunostained colorectal cancer images were analyzed with an automated tumor segmentation algorithm. The automated tools were validated by comparing the results from losslessly compressed and non-scaled images with results from conventional visual assessments. Percentage agreement and kappa statistics were calculated between results from compressed and scaled images and results from lossless and non-scaled images. Results Both of the studied image analysis methods showed good agreement between visual and automated results. In the automated IHC quantification, an agreement of over 98% and a kappa value of over 0.96 was observed between losslessly compressed and non-scaled images and combined compression ratios up to 1:50 and scaling down to 1:8. In automated tumor segmentation, an agreement of over 97% and a kappa value of over 0.93 was observed between losslessly compressed images and

  4. Solar-powered Rankine heat pump for heating and cooling

    Science.gov (United States)

    Rousseau, J.

    1978-01-01

    The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

  5. RANKINE-HUGONIOT RELATIONS IN RELATIVISTIC COMBUSTION WAVES

    International Nuclear Information System (INIS)

    Gao Yang; Law, Chung K.

    2012-01-01

    As a foundational element describing relativistic reacting waves of relevance to astrophysical phenomena, the Rankine-Hugoniot relations classifying the various propagation modes of detonation and deflagration are analyzed in the relativistic regime, with the results properly degenerating to the non-relativistic and highly relativistic limits. The existence of negative-pressure downstream flows is noted for relativistic shocks, which could be of interest in the understanding of the nature of dark energy. Entropy analysis for relativistic shock waves is also performed for relativistic fluids with different equations of state (EoS), denoting the existence of rarefaction shocks in fluids with adiabatic index Γ < 1 in their EoS. The analysis further shows that weak detonations and strong deflagrations, which are rare phenomena in terrestrial environments, are expected to exist more commonly in astrophysical systems because of the various endothermic reactions present therein. Additional topics of relevance to astrophysical phenomena are also discussed.

  6. Organic Rankine Kilowatt Isotope Power System. Final phase I report

    International Nuclear Information System (INIS)

    1978-01-01

    On 1 August 1975 under Department of Energy Contract EN-77-C-02-4299, Sundstrand Energy Systems commenced development of a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980s and beyond. The KIPS is a 238 PuO 2 fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W/sub (e)/ with a minimum of system changes. The principal objectives of the Phase 1 development effort were to: conceptually design a flight system; design a Ground Demonstration System (GDS) that is prototypic of the flight system in order to prove the feasibility of the flight system design; fabricate and assemble the GDS; and performance and endurance test the GDS using electric heaters in lieu of the isotope heat source. Results of the work performed under the Phase 1 contract to 1 July 1978 are presented

  7. Optimal integration of organic Rankine cycles with industrial processes

    International Nuclear Information System (INIS)

    Hipólito-Valencia, Brígido J.; Rubio-Castro, Eusiel; Ponce-Ortega, José M.; Serna-González, Medardo; Nápoles-Rivera, Fabricio; El-Halwagi, Mahmoud M.

    2013-01-01

    Highlights: • An optimization approach for heat integration is proposed. • A new general superstructure for heat integration is proposed. • Heat process streams are simultaneously integrated with an organic Rankine cycle. • Better results can be obtained respect to other previously reported methodologies. - Abstract: This paper presents a procedure for simultaneously handling the problem of optimal integration of regenerative organic Rankine cycles (ORCs) with overall processes. ORCs may allow the recovery of an important fraction of the low-temperature process excess heat (i.e., waste heat from industrial processes) in the form of mechanical energy. An integrated stagewise superstructure is proposed for representing the interconnections and interactions between the HEN and ORC for fixed data of process streams. Based on the integrated superstructure, the optimization problem is formulated as a mixed integer nonlinear programming problem to simultaneously account for the capital and operating costs including the revenue from the sale of the shaft power produced by the integrated system. The application of this method is illustrated with three example problems. Results show that the proposed procedure provides significantly better results than an earlier developed method for discovering optimal integrated systems using a sequential approach, due to the fact that it accounts simultaneously for the tradeoffs between the capital and operating costs as well as the sale of the produced energy. Also, the proposed method is an improvement over the previously reported methods for solving the synthesis problem of heat exchanger networks without the option of integration with an ORC (i.e., stand-alone heat exchanger networks)

  8. Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami Nathan [Eaton Corporation

    2017-06-30

    Nearly 30% of fuel energy is not utilized and wasted in the engine exhaust. Organic Rankine Cycle (ORC) based waste heat recovery (WHR) systems offer a promising approach on waste energy recovery and improving the efficiency of Heavy-Duty diesel engines. Major barriers in the ORC WHR system are the system cost and controversial waste heat recovery working fluids. More than 40% of the system cost is from the additional heat exchangers (recuperator, condenser and tail pipe boiler). The secondary working fluid loop designed in ORC system is either flammable or environmentally sensitive. The Eaton team investigated a novel approach to reduce the cost of implementing ORC based WHR systems to Heavy-Duty (HD) Diesel engines while utilizing safest working fluids. Affordable Rankine Cycle (ARC) concept aimed to define the next generation of waste energy recuperation with a cost optimized WHR system. ARC project used engine coolant as the working fluid. This approach reduced the need for a secondary working fluid circuit and subsequent complexity. A portion of the liquid phase engine coolant has been pressurized through a set of working fluid pumps and used to recover waste heat from the exhaust gas recirculation (EGR) and exhaust tail pipe exhaust energy. While absorbing heat, the mixture is partially vaporized but remains a wet binary mixture. The pressurized mixed-phase engine coolant mixture is then expanded through a fixed-volume ratio expander that is compatible with two-phase conditions. Heat rejection is accomplished through the engine radiator, avoiding the need for a separate condenser. The ARC system has been investigated for PACCAR’s MX-13 HD diesel engine.

  9. Parametric investigation of working fluids for organic Rankine cycle applications

    International Nuclear Information System (INIS)

    Brown, J. Steven; Brignoli, Riccardo; Quine, Timothy

    2015-01-01

    This paper investigates working fluids for organic Rankine cycle (ORC) applications with a goal of identifying “ideal” working fluids for five renewable/alternative energy sources. It employs a methodology for screening and comparing with good engineering accuracy the thermodynamic performance potential of ORC operating with working fluids that are not well characterized experimentally or by high-accuracy equations of state. A wide range of “theoretical” working fluids are investigated with the goals to identify potential alternative working fluids and to guide future research and development efforts of working fluids. The “theoretical” working fluids investigated are described in terms of critical state properties, acentric factor, and ideal gas specific heat capacity at constant pressure and are obtained by parametrically varying each of these parameters. The performances of these “theoretical” working fluids are compared to the performances of several “real” working fluids. The study suggests a working fluid's critical temperature and its critical ideal gas molar heat capacity have the largest impact on the cycle efficiency and volumetric work output, with “ideal” working fluids for high efficiency possessing critical temperatures on the order of 100%–150% of the source temperature and possessing intermediate values of critical ideal gas molar heat capacity. - Highlights: • “Ideal” working fluids are investigated for organic Rankine cycles (ORC). • The thermodynamic space of “ideal” working fluids is parametrically investigated. • Five low- and high-temperature ORC applications are investigated. • 1620 “ideal” and several “real” working fluids per application are investigated.

  10. Theoretical thermodynamic analysis of Rankine power cycle with thermal driven pump

    International Nuclear Information System (INIS)

    Lakew, Amlaku Abie; Bolland, Olav; Ladam, Yves

    2011-01-01

    Highlights: → The work is focused on theoretical aspects of thermal driven pump (TDP) Rankine cycle. → The mechanical pump is replaced by thermal driven pump. → Important parameters of thermal driven pump Rankine cycle are investigated. → TDP Rankine cycle produce more power but it requires additional low grade heat. - Abstract: A new approach to improve the performance of supercritical carbon dioxide Rankine cycle which uses low temperature heat source is presented. The mechanical pump in conventional supercritical carbon dioxide Rankine cycle is replaced by thermal driven pump. The concept of thermal driven pump is to increase the pressure of a fluid in a closed container by supplying heat. A low grade heat source is used to increase the pressure of the fluid instead of a mechanical pump, this increase the net power output and avoid the need for mechanical pump which requires regular maintenance and operational cost. The thermal driven pump considered is a shell and tube heat exchanger where the working fluid is contained in the tube, a tube diameter of 5 mm is chosen to reduce the heating time. The net power output of the Rankine cycle with thermal driven pump is compared to that of Rankine cycle with mechanical pump and it is observed that the net power output is higher when low grade thermal energy is used to pressurize the working fluid. The thermal driven pump consumes additional heat at low temperature (60 o C) to pressurize the working fluid.

  11. Effects of TimeSlips on Cornell Scale for Depression in Dementia scores of senile dementia patients

    Directory of Open Access Journals (Sweden)

    Hui-Ying Chen

    2016-03-01

    Conclusion: TimeSlips is beneficial to relieve depressive symptoms and ameliorate the emotions of mild or moderate senile dementia patients, thus improving their life quality and reducing the burden of their caregivers. A large-scale experimental research on TimeSlips with rigorous design is proposed for further studies.

  12. An Operational Definition of Learning Disabilities (Cognitive Domain) Using WISC Full Scale IQ and Peabody Individual Achievement Test Scores.

    Science.gov (United States)

    Brenton, Beatrice White; Gilmore, Doug

    An operational index of discrepancy between ability and achievement using the Wechsler Intelligence Scale for Children and the Peabody Individual Achievement Test (PIAT) was tested with 50 male and 10 female legally identified learning disabled (LD) children (mean age 9 years 2 months). Use of the index identified 74% of the males and 30% of the…

  13. Potential application of Rankine and He-Brayton cycles to sodium fast reactors

    International Nuclear Information System (INIS)

    Perez-Pichel, G.D.; Linares, J.I.; Herranz, L.E.; Moratilla, B.Y.

    2011-01-01

    Highlights: → This paper has been focused on thermal efficiency of several Rankine and Brayton cycles for SFR. → A sub-critical Rankine configuration could reach a thermal efficiency higher than 43%. → It could be increased to almost 45% using super-critical configurations. → Brayton cycles thermal performance can be enhanced by adding a super-critical organic fluid Rankine cycle. → The moderate coolant temperature at the reactor makes Brayton configurations have poorer. - Abstract: Traditionally all the demos and/or prototypes of the sodium fast reactor (SFR) technology with power output, have used a steam sub-critical Rankine cycle. Sustainability requirement of Gen. IV reactors recommends exploring alternate power cycle configurations capable of reaching high thermal efficiency. By adopting the anticipated working parameters of next SFRs, this paper investigates the potential of some Rankine and He-Brayton layouts to reach thermal efficiencies as high as feasible, so that they could become alternates for SFR reactor balance of plant. The assessment has encompassed from sub-critical to super-critical Rankine cycles and combined cycles based on He-Brayton gas cycles of different complexity coupled to Organic Rankine Cycles. The sub-critical Rankine configuration reached at thermal efficiency higher than 43%, which has been shown to be a superior performance than any of the He-Brayton configurations analyzed. By adopting a super-critical Rankine arrangement, thermal efficiency would increase less than 1.5%. In short, according to the present study a sub-critical layout seems to be the most promising configuration for all those upcoming prototypes to be operated in the short term (10-15 years). The potential of super-critical CO 2 -Brayton cycles should be explored for future SFRs to be deployed in a longer run.

  14. Predictors of short-term outcome in patients with acute middle cerebral artery occlusion: unsuitability of fluid-attenuated inversion recovery vascular hyperintensity scores

    Directory of Open Access Journals (Sweden)

    Chan-chan Li

    2018-01-01

    Full Text Available Fluid-attenuated inversion recovery (FLAIR vascular hyperintensity (FVH is used to assess leptomeningeal collateral circulation, but clinical outcomes of patients with FVH can be very different. The aim of the present study was to assess a FVH score and explore its relationship with clinical outcomes. Patients with acute ischemic stroke due to middle cerebral artery M1 occlusion underwent magnetic resonance imaging and were followed up at 10 days (National Institutes of Health Stroke Scale and 90 days (modified Rankin Scale to determine short-term clinical outcomes. Effective collateral circulation indirectly improved recovery of neurological function and short-term clinical outcome by extending the size of the pial penumbra and reducing infarct lesions. FVH score showed no correlation with 90-day functional clinical outcome and was not sufficient as an independent predictor of short-term clinical outcome.

  15. Creating a brief rating scale for the assessment of learning disabilities using reliability and true score estimates of the scale's items based on the Rasch model.

    Science.gov (United States)

    Sideridis, Georgios; Padeliadu, Susana

    2013-01-01

    The purpose of the present studies was to provide the means to create brief versions of instruments that can aid the diagnosis and classification of students with learning disabilities and comorbid disorders (e.g., attention-deficit/hyperactivity disorder). A sample of 1,108 students with and without a diagnosis of learning disabilities took part in study 1. Using information from modern theory methods (i.e., the Rasch model), a scale was created that included fewer than one third of the original battery items designed to assess reading skills. This best item synthesis was then evaluated for its predictive and criterion validity with a valid external reading battery (study 2). Using a sample of 232 students with and without learning disabilities, results indicated that the brief version of the scale was equally effective as the original scale in predicting reading achievement. Analysis of the content of the brief scale indicated that the best item synthesis involved items from cognition, motivation, strategy use, and advanced reading skills. It is suggested that multiple psychometric criteria be employed in evaluating the psychometric adequacy of scales used for the assessment and identification of learning disabilities and comorbid disorders.

  16. Analysis of a rotating spool expander for Organic Rankine Cycle applications

    Science.gov (United States)

    Krishna, Abhinav

    Increasing interest in recovering or utilizing low-grade heat for power generation has prompted a search for ways in which the power conversion process may be enhanced. Amongst the conversion systems, the Organic Rankine Cycle (ORC) has generated an enormous amount of interest amongst researchers and system designers. Nevertheless, component level technologies need to be developed and match the range of potential applications. In particular, technical challenges associated with scaling expansion machines (turbines) from utility scale to commercial scale have prevented widespread adoption of the technology. In this regard, this work focuses on a novel rotating spool expansion machine at the heart of an Organic Rankine Cycle. A comprehensive, deterministic simulation model of the rotating spool expander is developed. The comprehensive model includes a detailed geometry model of the spool expander and the suction valve mechanism. Sub-models for mass flow, leakage, heat transfer and friction within the expander are also developed. Apart from providing the ability to characterize the expander in a particular system, the model provides a valuable tool to study the impact of various design variables on the performance of the machine. The investigative approach also involved an experimental program to assess the performance of a working prototype. In general, the experimental data showed that the expander performance was sub-par, largely due to the mismatch of prevailing operating conditions and the expander design criteria. Operating challenges during the shakedown tests and subsequent sub-optimal design changes also detracted from performance. Nevertheless, the results of the experimental program were sufficient for a proof-of-concept assessment of the expander and for model validation over a wide range of operating conditions. The results of the validated model reveal several interesting details concerning the expander design and performance. For example, the match

  17. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2018-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  18. Analysis of hot spots in boilers of organic Rankine cycle units during transient operation

    DEFF Research Database (Denmark)

    Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycle...... and fluid decomposition. It is demonstrated thatthe use of a spray attemperator can mitigate the problems of local overheating of the organic compound.As a practical consequence, this paper provides guidelines for safe and reliable operation of organicRankine cycle power modules on offshore installations....

  19. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2017-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  20. FLUOROETHERS AS A WORKING FLUIDS FOR LOW TEMPERATURE ORGANIC RANKINE CYCLE

    Directory of Open Access Journals (Sweden)

    Artemenko S.V

    2014-12-01

    Full Text Available Hydrofluoroethers as a new class of working fluids for the organic Rankine cycle have been considered to utilize the low-potential waste heat. Temperature range 300…400 K was chosen to provide energy conversion of waste heat from fuel cells. The direct assessment of the efficiency criteria for the Rankine cycle via artificial neural networks (ANN was used. To create ANN the critical parameters of substance and normal boiling temperature as input were chosen. The forecast of efficiency criteria for the Rankine cycle as output parameter which reproduces the coefficient of performance with high accuracy and without thermodynamic property calculations was presented.

  1. Associations of scores on the White-Campbell Psychological Birth Order Inventory and the Kern Lifestyle Scale.

    Science.gov (United States)

    White, J; Campbell, L; Stewart, A

    1995-12-01

    This study investigated the relations among psychological birth order, actual birth order, and lifestyle. The study also further examined the convergent validity of the White-Campbell Psychological Birth Order Inventory. This inventory and Kern's Lifestyle Scale were administered to 126 individuals in a southeastern urban university. The several analyses of variance and canonical correlation analysis (1) supported a stronger relationship between psychological birth order and lifestyle than between actual birth order and lifestyle, (2) identified differential relationships between particular birth-order positions and lifestyle scales that were predicted and in accord with Adlerian theory, and (3) further supported the validity of the inventory. The results reaffirmed the lifestyle pattern and birth-order characterizations of Adlerian theory.

  2. Score of Inattention Subscale of ADHD Rating Scale-IV is Significantly Higher for AD/HD than PDD.

    OpenAIRE

    Fujibayashi, Hiromi; Kitayama, Shinji; Matsuo, Masafumi

    2010-01-01

    Attention-deficit/hyperactivity disorder (AD/HD) and pervasive developmental disorder (PDD) must be differentiated because the respective treatments are different. However, they are difficult to distinguish because they often show similar symptoms. At our hospital, we have the rearer of a patient answer both the ADHD Rating Scale-IV (ADHD-RS) and the Autism Spectrum Screening Questionnaire (ASSQ), and use the results as an aid for the diagnosis of AD/HD or PDD. These results were compared wit...

  3. Influence of Deep Breathing on Heart Rate Variability in Parkinson's Disease: Co-relation with Severity of Disease and Non-Motor Symptom Scale Score.

    Science.gov (United States)

    Bidikar, Mukta Pritam; Jagtap, Gayatri J; Chakor, Rahul T

    2014-07-01

    Dysautonomia and non-motor symptoms (NMS) in Parkinson's disease (PD) are frequent, disabling and reduce quality of life of patient. There is a paucity of studies on autonomic dysfunction in PD in Indian population. The study aimed to evaluate autonomic dysfunction in PD patients and co-relate the findings with severity of PD and Non-Motor Symptoms Scale (NMSS) score. We evaluated autonomic function in 30 diagnosed patients of PD (age 55-70 years) and 30 healthy age-matched controls by 3 min deep breathing test (DBT). NMSS was used to identify non-motor symptoms and Hoehn and Yahr (HY) Scale to grade severity of PD. The DBT findings were co-related with severity of PD (HY staging) and NMSS score. DBT was found to be abnormal in 40% while it was on borderline in 33.3% of PD patients. There was a statistically significant difference (psymptom. A negative co-relation was found between results of deep breathing test and clinical severity of disease and NMSS score. Abnormalities of autonomic function and NMS were integral and present across all the stages of PD patients. Early recognition and treatment of these may decrease morbidity and improve quality of life of PD patients.

  4. Lord-Wingersky Algorithm Version 2.0 for Hierarchical Item Factor Models with Applications in Test Scoring, Scale Alignment, and Model Fit Testing.

    Science.gov (United States)

    Cai, Li

    2015-06-01

    Lord and Wingersky's (Appl Psychol Meas 8:453-461, 1984) recursive algorithm for creating summed score based likelihoods and posteriors has a proven track record in unidimensional item response theory (IRT) applications. Extending the recursive algorithm to handle multidimensionality is relatively simple, especially with fixed quadrature because the recursions can be defined on a grid formed by direct products of quadrature points. However, the increase in computational burden remains exponential in the number of dimensions, making the implementation of the recursive algorithm cumbersome for truly high-dimensional models. In this paper, a dimension reduction method that is specific to the Lord-Wingersky recursions is developed. This method can take advantage of the restrictions implied by hierarchical item factor models, e.g., the bifactor model, the testlet model, or the two-tier model, such that a version of the Lord-Wingersky recursive algorithm can operate on a dramatically reduced set of quadrature points. For instance, in a bifactor model, the dimension of integration is always equal to 2, regardless of the number of factors. The new algorithm not only provides an effective mechanism to produce summed score to IRT scaled score translation tables properly adjusted for residual dependence, but leads to new applications in test scoring, linking, and model fit checking as well. Simulated and empirical examples are used to illustrate the new applications.

  5. Wechsler Intelligence Scale for Children 4th edition-Chinese version index scores in Taiwanese children with attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Yang, Pinchen; Cheng, Chung-Ping; Chang, Chen-Lin; Liu, Tai-Ling; Hsu, Hsiu-Yi; Yen, Cheng-Fang

    2013-02-01

    The Wechsler Intelligence Scale for Children 4th edition-Chinese version (WISC-IV-Chinese) has been in clinical use in Taiwan since 2007. Research is needed to determine how the WISC-IV, modified from its earlier version, will affect its interpretation in clinical practice in a Mandarin-speaking context. We attempted to use WISC-IV-Chinese scores to identify the cognitive strengths and weaknesses in 334 Taiwanese children with attention-deficit/hyperactivity disorder (ADHD). Comparison of cognitive profiles of WISC-IV-Chinese scores between subtypes of ADHD was also performed. The results indicated that the four-factor model of the WISC-IV-Chinese fitted well for Taiwanese children with ADHD. The profiles showed that performance in the index score of the Processing Speed Index was the weakness domain for the Taiwanese children with ADHD, as confirmed by two different kinds of analytic methods. Cognitive profile analysis of ADHD subtypes revealed children with inattentive subtypes to have a greater weakness in processing speed performance. The implications of the profiles of the index scores on the WISC-IV-Chinese version for Taiwanese children with ADHD were explored. © 2013 The Authors. Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology.

  6. Effect of Age on Glasgow Coma Scale in Patients with Moderate and Severe Traumatic Brain Injury: An Approach with Propensity Score-Matched Population

    Directory of Open Access Journals (Sweden)

    Cheng-Shyuan Rau

    2017-11-01

    Full Text Available Background: The most widely used methods of describing traumatic brain injury (TBI are the Glasgow Coma Scale (GCS and the Abbreviated Injury Scale (AIS. Recent evidence suggests that presenting GCS in older patients may be higher than that in younger patients for an equivalent anatomical severity of TBI. This study aimed to assess these observations with a propensity-score matching approach using the data from Trauma Registry System in a Level I trauma center. Methods: We included all adult patients (aged ≥20 years old with moderate to severe TBI from 1 January 2009 to 31 December 2016. Patients were categorized into elderly (aged ≥65 years and young adults (aged 20–64 years. The severity of TBI was defined by an AIS score in the head (AIS 3‒4 and 5 indicate moderate and severe TBI, respectively. We examined the differences in the GCS scores by age at each head AIS score. Unpaired Student’s t- and Mann–Whitney U-tests were used to analyze normally and non-normally distributed continuous data, respectively. Categorical data were compared using either the Pearson chi-square or two-sided Fisher’s exact tests. Matched patient populations were allocated in a 1:1 ratio according to the propensity scores calculated using NCSS software with the following covariates: sex, pre-existing chronic obstructive pulmonary disease, systolic blood pressure, hemoglobin, sodium, glucose, and alcohol level. Logistic regression was used to evaluate the effects of age on the GCS score in each head AIS stratum. Results: The study population included 2081 adult patients with moderate to severe TBI. These patients were categorized into elderly (n = 847 and young adults (n = 1234: each was exclusively further divided into three groups of patients with head AIS of 3, 4, or 5. In the 162 well-balanced pairs of TBI patients with head AIS of 3, the elderly demonstrated a significantly higher GCS score than the young adults (14.1 ± 2.2 vs. 13.1 ± 3

  7. The Alcohol Use Disorders Identification Scale (AUDIT) normative scores for a multiracial sample of Rhodes University residence students.

    Science.gov (United States)

    Young, Charles; Mayson, Tamara

    2010-06-01

    The objective of this research is to obtain accurate drinking norms for students living in the university residences in preparation for future social norms interventions that would allow individual students to compare their drinking to an appropriate reference group. Random cluster sampling was used to obtain data from 318 residence students who completed the Alcohol Use Disorders Identification Test (AUDIT), a brief, reliable and valid screening measure designed by the World Health Organisation (Babor et al. 2001). The Cronbach alpha coefficient of 0.83 reported for this multicultural sample is high, suggesting that the AUDIT may be reliably used in this and similar contexts. Normative scores are reported in the form of percentiles. Comparisons between the portions of students drinking safely and hazardously according to race and gender indicate that while male students are drinking no more hazardously than female students, white students drink far more hazardously than black students. These differences suggest that both race- and gender-specific norms would be essential for an effective social norms intervention in this multicultural South African context. Finally, the racialised drinking patterns might reflect an informal segregation of social space at Rhodes University.

  8. Reference Values for the Marx Activity Rating Scale in a Young Athletic Population: History of Knee Ligament Injury Is Associated With Higher Scores.

    Science.gov (United States)

    Cameron, Kenneth L; Peck, Karen Y; Thompson, Brandon S; Svoboda, Steven J; Owens, Brett D; Marshall, Stephen W

    2015-01-01

    Activity-related patient-reported outcome measures are an important component of assessment after knee ligament injury in young and physically active patients; however, normative data for most activity scales are limited. To present reference values by sex for the Marx Activity Rating Scale (MARS) within a young and physically active population while accounting for knee ligament injury history and sex. Cross-sectional study. Level 2. All incoming freshman entering a US Service Academy in June of 2011 were recruited to participate in this study. MARS was administered to 1169 incoming freshmen (203 women) who consented to participate within the first week of matriculation. All subjects were deemed healthy and medically fit for military service on admission. Subjects also completed a baseline questionnaire that asked for basic demographic information and injury history. We calculated means with standard deviations, medians with interquartile ranges, and percentiles for ordinal and continuous variables, and frequencies and proportions for dichotomous variables. We also compared median scores by sex and history of knee ligament injury using the Kruskal-Wallis test. MARS was the primary outcome of interest. The median MARS score was significantly higher for men when compared with women (χ(2) = 13.22, df = 1, P MARS scores between men and women (χ(2) = 0.47, df = 1, P = 0.493) who reported a history of injury. Overall, median MARS scores were significantly higher among those who reported a history of knee ligament injury when compared with those who did not (χ(2) = 9.06, df = 1, P = 0.003). Assessing activity as a patient-reported outcome after knee ligament injury is important, and reference values for these instruments need to account for the influence of prior injury and sex. © 2015 The Author(s).

  9. Predictive Accuracy of Violence Risk Scale-Sexual Offender Version Risk and Change Scores in Treated Canadian Aboriginal and Non-Aboriginal Sexual Offenders.

    Science.gov (United States)

    Olver, Mark E; Sowden, Justina N; Kingston, Drew A; Nicholaichuk, Terry P; Gordon, Audrey; Beggs Christofferson, Sarah M; Wong, Stephen C P

    2018-04-01

    The present study examined the predictive properties of Violence Risk Scale-Sexual Offender version (VRS-SO) risk and change scores among Aboriginal and non-Aboriginal sexual offenders in a combined sample of 1,063 Canadian federally incarcerated men. All men participated in sexual offender treatment programming through the Correctional Service of Canada (CSC) at sites across its five regions. The Static-99R was also examined for comparison purposes. In total, 393 of the men were identified as Aboriginal (i.e., First Nations, Métis, Circumpolar) while 670 were non-Aboriginal and primarily White. Aboriginal men scored significantly higher on the Static-99R and VRS-SO and had higher rates of sexual and violent recidivism; however, there were no significant differences between Aboriginal and non-Aboriginal groups on treatment change with both groups demonstrating close to a half-standard deviation of change pre and post treatment. VRS-SO risk and change scores significantly predicted sexual and violent recidivism over fixed 5- and 10-year follow-ups for both racial/ancestral groups. Cox regression survival analyses also demonstrated positive treatment changes to be significantly associated with reductions in sexual and violent recidivism among Aboriginal and non-Aboriginal men after controlling baseline risk. A series of follow-up Cox regression analyses demonstrated that risk and change score information accounted for much of the observed differences between Aboriginal and non-Aboriginal men in rates of sexual recidivism; however, marked group differences persisted in rates of general violent recidivism even after controlling for these covariates. The results support the predictive properties of VRS-SO risk and change scores with treated Canadian Aboriginal sexual offenders.

  10. www.common-metrics.org: a web application to estimate scores from different patient-reported outcome measures on a common scale.

    Science.gov (United States)

    Fischer, H Felix; Rose, Matthias

    2016-10-19

    Recently, a growing number of Item-Response Theory (IRT) models has been published, which allow estimation of a common latent variable from data derived by different Patient Reported Outcomes (PROs). When using data from different PROs, direct estimation of the latent variable has some advantages over the use of sum score conversion tables. It requires substantial proficiency in the field of psychometrics to fit such models using contemporary IRT software. We developed a web application ( http://www.common-metrics.org ), which allows estimation of latent variable scores more easily using IRT models calibrating different measures on instrument independent scales. Currently, the application allows estimation using six different IRT models for Depression, Anxiety, and Physical Function. Based on published item parameters, users of the application can directly estimate latent trait estimates using expected a posteriori (EAP) for sum scores as well as for specific response patterns, Bayes modal (MAP), Weighted likelihood estimation (WLE) and Maximum likelihood (ML) methods and under three different prior distributions. The obtained estimates can be downloaded and analyzed using standard statistical software. This application enhances the usability of IRT modeling for researchers by allowing comparison of the latent trait estimates over different PROs, such as the Patient Health Questionnaire Depression (PHQ-9) and Anxiety (GAD-7) scales, the Center of Epidemiologic Studies Depression Scale (CES-D), the Beck Depression Inventory (BDI), PROMIS Anxiety and Depression Short Forms and others. Advantages of this approach include comparability of data derived with different measures and tolerance against missing values. The validity of the underlying models needs to be investigated in the future.

  11. Recent research trends in organic Rankine cycle technology: A bibliometric approach

    DEFF Research Database (Denmark)

    Imran, Muhammad; Haglind, Fredrik; Asim, Muhammad

    2018-01-01

    This work describes the contribution of researchers around the world in the field of the organic Rankine cycle in the period 2000–2016. A bibliometric approach was applied to analyze the scientific publications in the field using the Scopus Elsevier database, together with Science Citation Index...... of active countries, institutes, authors, and journals in the organic Rankine cycle technology field. From 2000 to 2016, there were 2120 articles published by 3443 authors from 997 research institutes scattered over 71 countries. The total number of citations and impact factor are 36,739 and 4597...... are the leading countries in organic Rankine cycle research and account for 64% of the total number of publications. The core research activities in the field are mainly focused on applications of the organic Rankine cycle technology, working fluids selection/performance, cycle architecture, and design...

  12. Prospects of the use of nanofluids as working fluids for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Mondejar, Maria E.; Andreasen, Jesper G.; Regidor, Maria

    2017-01-01

    The search of novel working fluids for organic Rankine cycle power systems is driven by the recent regulations imposing additional phase-out schedules for substances with adverse environmental characteristics. Recently, nanofluids (i.e. colloidal suspensions of nanoparticles in fluids) have been...... suggested as potential working fluids for organic Rankine cycle power systems due to their enhanced thermal properties, potentially giving advantages with respect to the design of the components and the cycle performance. Nevertheless, a number of challenges concerning the use of nanofluids must...... the prospects of using nanofluids as working fluids for organic Rankine cycle power systems. As a preliminary study, nanofluids consisting of a homogenous and stable mixture of different nanoparticles types and a selected organic fluid are simulated on a case study organic Rankine cycle unit for waste heat...

  13. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B

    DEFF Research Database (Denmark)

    La Seta, Angelo; Meroni, Andrea; Andreasen, Jesper Graa

    2016-01-01

    Organic Rankine cycle (ORC) power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging...... due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly...... is the preliminary design of an organic Rankine cycle turbogenerator to increase the overall energy efficiency of an offshore platform. For an increase in expander pressure ratio from 10 to 35, the results indicate up to 10% point reduction in expander performance. This corresponds to a relative reduction in net...

  14. Performance Evaluation of a Helical Coil Heat Exchanger Working under Supercritical Conditions in a Solar Organic Rankine Cycle Installation

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2016-06-01

    Full Text Available Worldwide interest in low grade heat valorization using organic Rankine cycle (ORC technologies has increased significantly. A new small-scale ORC with a net capacity of 3 kW was efficiently integrated with a concentrated solar power technology for electricity generation. The excess heat source from Photovoltaic (PV collectors with a maximum temperature of 100 °C was utilized through a supercritical heat exchanger that uses R-404A as working medium. By ensuring supercritical heat transfer leads to a better thermal match in the heat exchanger and improved overall cycle efficiency. A helical coil heat exchanger was designed by using heat transfer correlations from the literature. These heat transfer correlations were derived for different conditions than ORCs and their estimated uncertainty is ~20%. In order to account for the heat transfer correlation uncertainties this component was oversized by 20%. Next, a prototype was built and installed in an integrated concentrated photovoltaic/thermal (CPV/T/Rankine system. The results from the measurements show that for better estimation of the sizing of the heat exchanger a more accurate correlation is required in order to design an optimal configuration and thus employ cheaper components.

  15. A Co-Powered Biomass and Concentrated Solar Power Rankine Cycle Concept for Small Size Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Eileen Tortora

    2013-03-01

    Full Text Available The present work investigates the matching of an advanced small scale Combined Heat and Power (CHP Rankine cycle plant with end-user thermal and electric load. The power plant consists of a concentrated solar power field co-powered by a biomass furnace to produce steam in a Rankine cycle, with a CHP configuration. A hotel was selected as the end user due to its high thermal to electric consumption ratio. The power plant design and its operation were modelled and investigated by adopting transient simulations with an hourly distribution. The study of the load matching of the proposed renewable power technology and the final user has been carried out by comparing two different load tracking scenarios, i.e., the thermal and the electric demands. As a result, the power output follows fairly well the given load curves, supplying, on a selected winter day, about 50 GJ/d of thermal energy and the 6 GJ/d of electric energy, with reduced energy dumps when matching the load.

  16. Education-stratified base-rate information on discrepancy scores within and between the Wechsler Adult Intelligence Scale--Third Edition and the Wechsler Memory Scale--Third Edition.

    Science.gov (United States)

    Dori, Galit A; Chelune, Gordon J

    2004-06-01

    The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997a) and the Wechsler Memory Scale--Third Edition (WMS-III; D. Wechsler, 1997b) are 2 of the most frequently used measures in psychology and neuropsychology. To facilitate the diagnostic use of these measures in the clinical decision-making process, this article provides information on education-stratified, directional prevalence rates (i.e., base rates) of discrepancy scores between the major index scores for the WAIS-III, the WMS-III, and between the WAIS-III and WMS-III. To illustrate how such base-rate data can be clinically used, this article reviews the relative risk (i.e., odds ratio) of empirically defined "rare" cognitive deficits in 2 of the clinical samples presented in the WAIS-III--WMS-III Technical Manual (The Psychological Corporation, 1997). ((c) 2004 APA, all rights reserved)

  17. Impact of baseline Diabetic Retinopathy Severity Scale scores on visual outcomes in the VIVID-DME and VISTA-DME studies.

    Science.gov (United States)

    Staurenghi, Giovanni; Feltgen, Nicolas; Arnold, Jennifer J; Katz, Todd A; Metzig, Carola; Lu, Chengxing; Holz, Frank G

    2017-10-19

    To evaluate intravitreal aflibercept versus laser in subgroups of patients with baseline Diabetic Retinopathy Severity Scale (DRSS) scores ≤43, 47, and ≥53 in VIVID-DME and VISTA-DME. Patients with diabetic macular oedema were randomised to receive intravitreal aflibercept 2 mg every 4 weeks (2q4), intravitreal aflibercept 2 mg every 8 weeks after five initial monthly doses (2q8), or macular laser photocoagulation at baseline with sham injections at every visit. These post hoc analyses evaluate outcomes based on baseline DRSS scores in patients in the integrated dataset. The 2q4 and 2q8 treatment groups were also pooled. 748 patients had a baseline DRSS score based on fundus photographs (≤43, n=301; 47, n=153; ≥53, n=294). At week 100, the least squares mean difference between treatment groups (effect of intravitreal aflibercept above that of laser, adjusting for baseline best-corrected visual acuity) was 8.9 (95% CI 5.99 to 11.81), 9.7 (95% CI 5.54 to 13.91), and 11.0 (95% CI 7.96 to 14.1) letters in those with baseline DRSS scores ≤43, 47, and ≥53, respectively. The proportions of patients with ≥2 step DRSS score improvement were greater in the intravitreal aflibercept group versus laser, respectively, for those with baseline DRSS scores of ≤43 (13% vs 5.9%), 47 (25.8% vs 4.5%), and ≥53 (64.5% vs 28.4%). Regardless of baseline DRSS score, functional outcomes were superior in intravitreal aflibercept-treated patients, demonstrating consistent treatment benefit across various baseline levels of retinopathy. NCT01331681 and NCT01363440, Post-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  18. Waste Heat-to-Power Using Scroll Expander for Organic Rankine Bottoming Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, John [TIAX LLC, Lexington, MA (United States); Smutzer, Chad [TIAX LLC, Lexington, MA (United States); Sinha, Jayanti [TIAX LLC, Lexington, MA (United States)

    2017-05-30

    The objective of this program was to develop a novel, scalable scroll expander for conversion of waste heat to power; this was accomplished and demonstrated in both a bench-scale system as well as a full-scale system. The expander is a key component in Organic Rankine Cycle (ORC) waste heat recovery systems which are used to convert medium-grade waste heat to electric power in a wide range of industries. These types of waste heat recovery systems allow for the capture of energy that would otherwise just be exhausted to the atmosphere. A scroll expander has the benefit over other technologies of having high efficiency over a broad range of operating conditions. The speed range of the TIAX expander (1,200 to 3,600 RPM) enables the shaft power output to directly drive an electric generator and produce 60 Hz electric power without incurring the equipment costs or losses of electronic power conversion. This greatly simplifies integration with the plant electric infrastructure. The TIAX scroll expander will reduce the size, cost, and complexity of a small-scale waste heat recovery system, while increasing the system efficiency compared to the prevailing ORC technologies at similar scale. During this project, TIAX demonstrated the scroll expander in a bench-scale test setup to have isentropic efficiency of 70-75% and operated it successfully for ~200 hours with minimal wear. This same expander was then installed in a complete ORC system driven by a medium grade waste heat source to generate 5-7 kW of electrical power. Due to funding constraints, TIAX was unable to complete this phase of testing, although the initial results were promising and demonstrated the potential of the technology.

  19. Arthritis self-efficacy scale scores in knee osteoarthritis: a systematic review and meta-analysis comparing arthritis self-management education with or without exercise.

    Science.gov (United States)

    Brand, Emily; Nyland, John; Henzman, Cameron; McGinnis, Mark

    2013-12-01

    Systematic literature review and meta-analysis. To evaluate studies that used arthritis self-management education alone or with exercise to improve Arthritis Self-Efficacy Scale scores of patients with knee osteoarthritis. Increasing self-efficacy may improve patient knee osteoarthritis symptom management and function. MEDLINE (1946-March 2013), CINAHL (1981-March 2013), and PsycINFO (1967-March 2013) databases were searched. Twenty-four studies, including 3163 subjects (women, n = 2547 [80.5%]; mean ± SD age, 65.3 ± 6.5 years), met the inclusion criteria. A meta-analysis was performed to compare the standardized mean difference effect sizes (Cohen d) of randomized controlled studies that used the Arthritis Self-Efficacy Scale pain (13 studies, n = 1906), other symptoms (13 studies, n = 1957), and function (5 studies, n = 399) subscales. Cohen d effect sizes were also calculated for cohort studies that used the Arthritis Self-Efficacy Scale pain (10 studies, n = 1035), other symptoms (9 studies, n = 913), and function (3 studies, n = 141) subscales. Both randomized controlled studies and cohort studies were grouped by intervention type (intervention 1, arthritis self-management education alone; intervention 2, arthritis self-management education with exercise), and effect sizes were compared (Mann-Whitney U tests, Pmanagement education with exercise displayed higher methodological quality scale scores (76.8 ± 13.1 versus 61.6 ± 19.6, P = .03). Statistically significant standardized effect-size differences between intervention 1 and intervention 2 were not observed. Small to moderate effect sizes were observed regardless of whether the intervention included exercise. Exercise interventions used in conjunction with arthritis self-management education programs need to be developed to better enhance the self-efficacy of patients with knee osteoarthritis. Therapy, level 2b-.

  20. Comparison of IMP-SPECT findings to subtest scores of Wechsler intelligence adult Scale-Revised in temporal lobe epilepsy patients

    Energy Technology Data Exchange (ETDEWEB)

    Kan, Rumiko; Uejima, Masahiko; Kaneko, Yuko; Miyamoto, Yuriko; Watabe, Manabu; Takahashi, Ruriko; Niwa, Shin-ichi; Shishido, Fumio [Fukushima Medical Coll. (Japan)

    1998-02-01

    In this study, 40 temporal lobe epilepsy patients were assessed, using the Laterality Index (LI) of ROI values in IMP-SPECT findings, Wechsler adult intelligence Scale-Revised (WAIS-R) and subtest scores. LIs of the frontal, temporal and occipital lobes were calculated as follows: the ROI values on the right side were subtracted from those on the left, and the results was divided by the sum of the ROI values on the right and left sides. The individual subtest scores on WAIS-R were standardized by all evaluation scores in order to exclude the influence of differences in intelligence level as much as possible. The results were as follows: there was a positive correlation (r=0.74, p<0.001) between LI values and the performance in Arithmetic in the left temporal lobe hypoperfusion group. And there was a positive correlation (r=0.50, p<0.02) between LI values and the performance in Vocabulary in the left temporal lobe hypoperfusion group. In the right occipital lobe hypoperfusion group, there was a negative correlation (r=-O.44, p

  1. Comparison of IMP-SPECT findings to subtest scores of Wechsler intelligence adult Scale-Revised in temporal lobe epilepsy patients

    International Nuclear Information System (INIS)

    Kan, Rumiko; Uejima, Masahiko; Kaneko, Yuko; Miyamoto, Yuriko; Watabe, Manabu; Takahashi, Ruriko; Niwa, Shin-ichi; Shishido, Fumio

    1998-01-01

    In this study, 40 temporal lobe epilepsy patients were assessed, using the Laterality Index (LI) of ROI values in IMP-SPECT findings, Wechsler adult intelligence Scale-Revised (WAIS-R) and subtest scores. LIs of the frontal, temporal and occipital lobes were calculated as follows: the ROI values on the right side were subtracted from those on the left, and the results was divided by the sum of the ROI values on the right and left sides. The individual subtest scores on WAIS-R were standardized by all evaluation scores in order to exclude the influence of differences in intelligence level as much as possible. The results were as follows: there was a positive correlation (r=0.74, p<0.001) between LI values and the performance in Arithmetic in the left temporal lobe hypoperfusion group. And there was a positive correlation (r=0.50, p<0.02) between LI values and the performance in Vocabulary in the left temporal lobe hypoperfusion group. In the right occipital lobe hypoperfusion group, there was a negative correlation (r=-O.44, p< O.05) between LI values and the performance in Coding. It is suggested that decreased blood flow areas detected by SPECT might influence brain function. (author)

  2. Validation of a Novel Scoring System for Changes in Skeletal Manifestations of Hypophosphatasia in Newborns, Infants, and Children: The Radiographic Global Impression of Change Scale.

    Science.gov (United States)

    Whyte, Michael P; Fujita, Kenji P; Moseley, Scott; Thompson, David D; McAlister, William H

    2018-05-01

    Hypophosphatasia (HPP) is the heritable metabolic disease characterized by impaired skeletal mineralization due to low activity of the tissue-nonspecific isoenzyme of alkaline phosphatase. Although HPP during growth often manifests with distinctive radiographic skeletal features, no validated method was available to quantify them, including changes over time. We created the Radiographic Global Impression of Change (RGI-C) scale to assess changes in the skeletal burden of pediatric HPP. Site-specific pairs of radiographs of newborns, infants, and children with HPP from three clinical studies of asfotase alfa, an enzyme replacement therapy for HPP, were obtained at baseline and during treatment. Each pair was scored by three pediatric radiologists ("raters"), with nine raters across the three studies. Intrarater and interrater agreement was determined by weighted Kappa coefficients. Interrater reliability was assessed using intraclass correlation coefficients (ICCs) and by two-way random effects analysis of variance (ANOVA) and a mixed-model repeated measures ANOVA. Pearson correlation coefficients evaluated relationships of the RGI-C to the Rickets Severity Scale (RSS), Pediatric Outcomes Data Collection Instrument Global Function Parent Normative Score, Childhood Health Assessment Questionnaire Disability Index, 6-Minute Walk Test percent predicted, and Z-score for height in patients aged 6 to 12 years at baseline. Eighty-nine percent (8/9) of raters showed substantial or almost perfect intrarater agreement of sequential RGI-C scores (weighted Kappa coefficients, 0.72 to 0.93) and moderate or substantial interrater agreement (weighted Kappa coefficients, 0.53 to 0.71) in patients aged 0 to 12 years at baseline. Moderate-to-good interrater reliability was observed (ICC, 0.57 to 0.65). RGI-C scores were significantly (p ≤ 0.0065) correlated with the RSS and with measures of global function, disability, endurance, and growth in the patients aged 6 to 12 years at

  3. Rankin-Selberg methods for closed string amplitudes

    CERN Document Server

    Pioline, Boris

    2014-01-01

    After integrating over supermoduli and vertex operator positions, scattering amplitudes in superstring theory at genus $h\\leq 3$ are reduced to an integral of a Siegel modular function of degree $h$ on a fundamental domain of the Siegel upper half plane. A direct computation is in general unwieldy, but becomes feasible if the integrand can be expressed as a sum over images under a suitable subgroup of the Siegel modular group: if so, the integration domain can be extended to a simpler domain at the expense of keeping a single term in each orbit -- a technique known as the Rankin-Selberg method. Motivated by applications to BPS-saturated amplitudes, Angelantonj, Florakis and I have applied this technique to one-loop modular integrals where the integrand is the product of a Siegel-Narain theta function times a weakly, almost holomorphic modular form. I survey our main results, and take some steps in extending this method to genus greater than one.

  4. Quasi-dynamic model for an organic Rankine cycle

    International Nuclear Information System (INIS)

    Bamgbopa, Musbaudeen O.; Uzgoren, Eray

    2013-01-01

    Highlights: • Study presents a simplified transient modeling approach for an ORC under variable heat input. • The ORC model is presented as a synthesis of its models of its sub-components. • The model is compared to benchmark numerical simulations and experimental data at different stages. - Abstract: When considering solar based thermal energy input to an organic Rankine cycle (ORC), intermittent nature of the heat input does not only adversely affect the power output but also it may prevent ORC to operate under steady state conditions. In order to identify reliability and efficiency of such systems, this paper presents a simplified transient modeling approach for an ORC operating under variable heat input. The approach considers that response of the system to heat input variations is mainly dictated by the evaporator. Consequently, overall system is assembled using dynamic models for the heat exchangers (evaporator and condenser) and static models of the pump and the expander. In addition, pressure drop within heat exchangers is neglected. The model is compared to benchmark numerical and experimental data showing that the underlying assumptions are reasonable for cases where thermal input varies in time. Furthermore, the model is studied on another configuration and mass flow rates of both the working fluid and hot water and hot water’s inlet temperature to the ORC unit are shown to have direct influence on the system’s response

  5. ALKASYS, Rankine-Cycle Space Nuclear Power System

    International Nuclear Information System (INIS)

    2001-01-01

    1 - Description of program or function: The program ALKASYS is used for the creation of design concepts of multimegawatt space power systems that employ potassium Rankine power conversion cycles. 2 - Method of solution: ALKASYS calculates performance and design characteristics and mass estimates for the major subsystems composing the total power system. Design and engineering performance characteristics are determined by detailed engineering procedures rather than by empirical algorithms. Mass estimates are developed using basic design principles augmented in some cases by empirical coefficients determined from the literature. The reactor design is based on a fast spectrum, metallic-clad rod fuel element containing UN pellets. 3 - Restrictions on the complexity of the problem: ALKASYS was developed primarily for the analysis of systems with electric power in the range from 1,000 to 25,000 kW(e) and full-power life from 1 to 10 years. The program should be used with caution in systems that are limited by heat flux (which might indicate need for extended surfaces on fuel elements) or criticality (which might indicate the need for other geometries or moderators)

  6. Rankine cycle generators using geothermal fluids. Final progress report

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The Rankine Cycle generator was delivered and installed at Gila Hot Springs. Trial runs were made at that time, using Freon 12 as the expansion fluid. These tests showed that the boiler capacity was inadequate. It could not extract enough heat to generate sufficient volumes of Freon gas at the heat and pressure necessary to operate the system at an acceptable level. Increasing and decreasing the flow of hot water had a direct influence on efficiency, but it was not a linear relationship. Added amounts of hot water increased the power very little, but raised the water temperature at the discharge point. This implied that the heat exchange capacity of the boiler was saturated. The reverse was found in the condenser system. There was little increase in pressure of the condenser when we switched from static to run mode. Efficiency was maintained even when the cold water flow was reduced as much as 40%. The tests using Freon 12 resulted in the conclusion that the boiler volume needs to be increased and/or the configuration changed to radically increase its efficiency.

  7. Organic Rankine cycle - review and research directions in engine applications

    Science.gov (United States)

    Panesar, Angad

    2017-11-01

    Waste heat to power conversion using Organic Rankine Cycles (ORC) is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2) are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

  8. Performance analysis of organic Rankine cycles using different working fluids

    Directory of Open Access Journals (Sweden)

    Zhu Qidi

    2015-01-01

    Full Text Available Low-grade heat from renewable or waste energy sources can be effectively recovered to generate power by an organic Rankine cycle (ORC in which the working fluid has an important impact on its performance. The thermodynamic processes of ORCs using different types of organic fluids were analyzed in this paper. The relationships between the ORC’s performance parameters (including evaporation pressure, condensing pressure, outlet temperature of hot fluid, net power, thermal efficiency, exergy efficiency, total cycle irreversible loss, and total heat-recovery efficiency and the critical temperatures of organic fluids were established based on the property of the hot fluid through the evaporator in a specific working condition, and then were verified at varied evaporation temperatures and inlet temperatures of the hot fluid. Here we find that the performance parameters vary monotonically with the critical temperatures of organic fluids. The values of the performance parameters of the ORC using wet fluids are distributed more dispersedly with the critical temperatures, compared with those of using dry/isentropic fluids. The inlet temperature of the hot fluid affects the relative distribution of the exergy efficiency, whereas the evaporation temperature only has an impact on the performance parameters using wet fluid.

  9. Utilisation of diesel engine waste heat by Organic Rankine Cycle

    International Nuclear Information System (INIS)

    Kölsch, Benedikt; Radulovic, Jovana

    2015-01-01

    In this paper, three different organic liquids were investigated as potential working fluids in an Organic Rankine Cycle. Performance of Methanol, Toluene and Solkatherm SES36 was modelled in an ORC powered by a diesel engine waste heat. The ORC model consists of a preheater, evaporator, superheater, turbine, pump and two condensers. With variable maximum cycle temperatures and high cycle pressures, the thermal efficiency, net power output and overall heat transfer area have been evaluated. Methanol was found to have the best thermal performance, but also required the largest heat transfer area. While Toluene achieved lower thermal efficiency, it showed great work potential at high pressures and relatively low temperatures. Our model identified the risks associated with employing these fluids in an ORC: methanol condensing during the expansion and toluene not sufficiently superheated at the turbine inlet, which can compromise the cycle operation. The best compromise between the size of heat exchanger and thermodynamic performance was found for Methanol ORC at intermediate temperatures and high pressures. Flammability and toxicity, however, remain the obstacles for safe implementation of both fluids in ORC systems. - Highlights: • ORC powered by diesel-engine waste heat was developed. • Methanol, Toluene and Solkatherm were considered as working fluids. • Methanol was selected due to the best overall thermal performance. • Optimal cycle operating parameters and heat exchanger area were evaluated

  10. Bottoming micro-Rankine cycles for micro-gas turbines

    International Nuclear Information System (INIS)

    Invernizzi, Costante; Iora, Paolo; Silva, Paolo

    2007-01-01

    This paper investigates the possibility of enhancing the performances of micro-gas turbines through the addition of a bottoming organic Rankine cycle which recovers the thermal power of the exhaust gases typically available in the range of 250-300 o C. The ORC cycles are particularly suitable for the recovery of heat from sources at variable temperatures, and for the generation of medium to small electric power. With reference to a micro-gas turbine with a size of about 100 kWe, a combined configuration could increase the net electric power by about 1/3, yielding an increase of the electrical efficiency of up to 40%. A specific analysis of the characteristics of different classes of working fluids is carried out in order to define a procedure to select the most appropriate fluid, capable of satisfying both environmental (ozone depletion potential, global warming potential) and technical (flammability, toxicity, fluid critical temperature and molecular complexity) concerns. Afterwards, a thermodynamic analysis is performed to ascertain the most favourable cycle thermodynamic conditions, from the point of view of heat recovery. Furthermore, a preliminary design of the ORC turbine (number of stages, outer diameter and rotational speed) is carried out

  11. Internal Combustion Engine (ICE) bottoming with Organic Rankine Cycles (ORCs)

    International Nuclear Information System (INIS)

    Vaja, Iacopo; Gambarotta, Agostino

    2010-01-01

    This paper describes a specific thermodynamic analysis in order to efficiently match a vapour cycle to that of a stationary Internal Combustion Engine (ICE). Three different working fluids are considered to represent the main classes of fluids, with reference to the shape of the vapour lines in the T-s diagram: overhanging, nearly isoentropic and bell shaped. First a parametric analysis is conducted in order to determine optimal evaporating pressures for each fluid. After which three different cycles setups are considered: a simple cycle with the use of only engine exhaust gases as a thermal source, a simple cycle with the use of exhaust gases and engine cooling water and a regenerated cycle. A second law analysis of the cycles is performed, with reference to the available heat sources. This is done in order to determine the best fluid and cycle configuration to be employed, the main parameters of the thermodynamic cycles and the overall efficiency of the combined power system. The analysis demonstrates that a 12% increase in the overall efficiency can be achieved with respect to the engine with no bottoming; nevertheless it has been observed that the Organic Rankine Cycles (ORCs) can recover only a small fraction of the heat released by the engine through the cooling water.

  12. Thermodynamic analysis of a simple Organic Rankine Cycle

    International Nuclear Information System (INIS)

    Javanshir, Alireza; Sarunac, Nenad

    2017-01-01

    Thermodynamic performance (thermal efficiency and net power output) of a simple subcritical and supercritical Organic Rankine Cycle (ORC) was analyzed over a range of operating conditions for a number of working fluids to determine the effect of operating parameters on cycle performance and select the best working fluid. The results show that for an ORC operating with a dry working fluid, thermal efficiency decreases with an increase in the turbine inlet temperature (TIT) due to the convergence of the isobaric lines with temperature. The results also show that efficiency of an ORC operating with isentropic working fluids is higher compared to the dry and wet fluids, and working fluids with higher specific heat capacity provide higher cycle net power output. New expressions for thermal efficiency of a subcritical and supercritical simple ORC are proposed. For a subcritical ORC without the superheat, thermal efficiency is expressed as a function of the Figure of Merit (FOM), while for the superheated subcritical ORC thermal efficiency is given in terms of the modified Jacob number. For the supercritical ORC, thermal efficiency is expressed as a function of dimensionless temperature. - Highlights: • Analyzing thermodynamic performance of ORC over a range of operating conditions. • Selecting the best working fluid suitable for a simple ORC. • Proposing new expressions for thermal efficiency of a simple ORC.

  13. Performance of an organic Rankine cycle with multicomponent mixtures

    International Nuclear Information System (INIS)

    Chaitanya Prasad, G.S.; Suresh Kumar, C.; Srinivasa Murthy, S.; Venkatarathnam, G.

    2015-01-01

    There is a renewed interest in ORC (organic Rankine cycle) systems for power generation using solar thermal energy. Many authors have studied the performance of ORC with different pure fluids as well as binary zeotropic mixtures in order to improve the thermal efficiency. It has not been well appreciated that zeotropic mixtures can also be used to reduce the size and cost of an ORC system. The main objective of this paper is to present mixtures that help reduce the cost while maintaining high thermal efficiency. The proposed method also allows us to design an optimum mixture for a given expander. This new approach is particularly beneficial for designing mixtures for small ORC systems operating with solar thermal energy. A number of examples are presented to demonstrate this concept. - Highlights: • The performance of an ORC operating with different zeotropic multicomponent mixtures is presented. • A thermodynamic method is proposed for the design of multicomponent mixtures for ORC power plants. • High exergy efficiency as well as high volumetric expander work can be achieved with appropriate mixtures. • The method allows design of mixtures that can be used with off-the-shelf positive displacement expanders

  14. Biogas Engine Waste Heat Recovery Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Alberto Benato

    2017-03-01

    Full Text Available Italy is a leading country in the biogas sector. Energy crops and manure are converted into biogas using anaerobic digestion and, then, into electricity using internal combustion engines (ICEs. Therefore, there is an urgent need for improving the efficiency of these engines taking the real operation into account. To this purpose, in the present work, the organic Rankine cycle (ORC technology is used to recover the waste heat contained in the exhaust gases of a 1 MWel biogas engine. The ICE behavior being affected by the biogas characteristics, the ORC unit is designed, firstly, using the ICE nameplate data and, then, with data measured during a one-year monitoring activity. The optimum fluid and the plant configuration are selected in both cases using an “in-house” optimization tool. The optimization goal is the maximization of the net electric power while the working fluid is selected among 115 pure fluids and their mixtures. Results show that a recuperative ORC designed using real data guarantees a 30% higher net electric power than the one designed with ICE nameplate conditions.

  15. Entorhinal cortex volume measured with 3T MRI is positively correlated with the Wechsler memory scale-revised logical/verbal memory score for healthy subjects

    International Nuclear Information System (INIS)

    Goto, Masami; Abe, Osamu; Takao, Hidemasa; Inano, Sachiko; Mori, Harushi; Kunimatsu, Akira; Ohtomo, Kuni; Miyati, Tosiaki; Yoshikawa, Takeharu; Hayashi, Naoto; Kabasawa, Hiroyuki; Aoki, Shigeki; Ino, Kenji; Iida, Kyouhito; Yano, Keiichi

    2011-01-01

    Previous studies revealed a correlation between local brain volume and cognitive function. The aim of the present study was to investigate the correlation between local gray matter volume and the Wechsler Memory Scale-Revised (WMS-R) logical/verbal memory (WMS-R-verbal) score in healthy adults using a 3 Tesla magnetic resonance scanner and voxel-based morphometry (VBM). T1-weighted magnetic resonance images were obtained in 1,169 healthy adults. The T1-weighted images in native space were bias-corrected, spatially normalized, and segmented into gray matter, white matter, and cerebrospinal fluid images with Statistical Parametric Mapping 5. To investigate regionally the specific effects of the WMS-R-verbal score on the gray matter images, simple regression analysis was performed by VBM treating age, total intracranial volume, and gender as confounding covariates. A P value of less than 0.05 corrected with false discovery rate in voxel difference was considered to be statistically significant. Our study showed a significant positive correlation between the WMS-R-verbal score and the bilateral entorhinal cortex volume. In the right entorhinal, T value is 4.75, and the size of the clusters is 155 voxels. In the left entorhinal, T value is 4.08, and the size of the clusters is 23 voxels. A significant negative correlation was not found. To our knowledge, this is the first VBM study showing that entorhinal cortex volume is positively correlated with the WMS-R-verbal score for healthy subjects. Therefore, in our structural neuroimaging study, we add evidence to the hypothesis that the entorhinal cortex is involved in verbal memory processing. (orig.)

  16. Entorhinal cortex volume measured with 3T MRI is positively correlated with the Wechsler memory scale-revised logical/verbal memory score for healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Masami [University of Tokyo Hospital, Department of Radiological Technology, Graduate School of Medicine, Tokyo (Japan); Kanazawa University, Tsunomatyou, Graduate School of Medical Science, Kanazawa (Japan); Abe, Osamu; Takao, Hidemasa; Inano, Sachiko; Mori, Harushi; Kunimatsu, Akira; Ohtomo, Kuni [University of Tokyo Hospital, Department of Radiology, Tokyo (Japan); Miyati, Tosiaki [Kanazawa University, Tsunomatyou, Graduate School of Medical Science, Kanazawa (Japan); Yoshikawa, Takeharu; Hayashi, Naoto [University of Tokyo Hospital, Department of Computational Diagnostic Radiology and Preventive Medicine, Tokyo (Japan); Kabasawa, Hiroyuki [GE Healthcare, Japan Applied Science Laboratory, Hino (Japan); Aoki, Shigeki [Juntendo University, Department of Radiology, Tokyo (Japan); Ino, Kenji; Iida, Kyouhito; Yano, Keiichi [University of Tokyo Hospital, Department of Radiological Technology, Graduate School of Medicine, Tokyo (Japan)

    2011-08-15

    Previous studies revealed a correlation between local brain volume and cognitive function. The aim of the present study was to investigate the correlation between local gray matter volume and the Wechsler Memory Scale-Revised (WMS-R) logical/verbal memory (WMS-R-verbal) score in healthy adults using a 3 Tesla magnetic resonance scanner and voxel-based morphometry (VBM). T1-weighted magnetic resonance images were obtained in 1,169 healthy adults. The T1-weighted images in native space were bias-corrected, spatially normalized, and segmented into gray matter, white matter, and cerebrospinal fluid images with Statistical Parametric Mapping 5. To investigate regionally the specific effects of the WMS-R-verbal score on the gray matter images, simple regression analysis was performed by VBM treating age, total intracranial volume, and gender as confounding covariates. A P value of less than 0.05 corrected with false discovery rate in voxel difference was considered to be statistically significant. Our study showed a significant positive correlation between the WMS-R-verbal score and the bilateral entorhinal cortex volume. In the right entorhinal, T value is 4.75, and the size of the clusters is 155 voxels. In the left entorhinal, T value is 4.08, and the size of the clusters is 23 voxels. A significant negative correlation was not found. To our knowledge, this is the first VBM study showing that entorhinal cortex volume is positively correlated with the WMS-R-verbal score for healthy subjects. Therefore, in our structural neuroimaging study, we add evidence to the hypothesis that the entorhinal cortex is involved in verbal memory processing. (orig.)

  17. Ischemic Volume and Neurological Deficit: Correlation of Computed Tomography Perfusion with the National Institutes of Health Stroke Scale Score in Acute Ischemic Stroke.

    Science.gov (United States)

    Furlanis, Giovanni; Ajčević, Miloš; Stragapede, Lara; Lugnan, Carlo; Ridolfi, Mariana; Caruso, Paola; Naccarato, Marcello; Ukmar, Maja; Manganotti, Paolo

    2018-04-30

    The National Institutes of Health Stroke Scale (NIHSS) is the most adopted stroke patients' evaluation tool in emergency settings to assess the severity of stroke and to determine the patients' eligibility for specific treatments. Computed tomography perfusion (CTP) is crucial to identify salvageable tissue that can benefit from the reperfusion treatment. The aim of this study is to identify the relation between the NIHSS scores and the hypoperfused volumes evaluated by CTP in patients with hyperacute ischemic stroke. This retrospective study was conducted on 105 patients with ischemic stroke who underwent NIHSS assessment and CTP in the hyperacute phase. Hypoperfused volume was evaluated by CTP maps processed with semi-automatic algorithm. An analysis was conducted to determine the degree of correlation between the NIHSS scores and the ischemic lesion volumes and to investigate the relation between the anterior and the posterior circulation strokes, as well as between the right and the left hemispheric strokes. A significant correlation was found between ischemic volume and NIHSS score at baseline (r = .82; P correlation was identified in the anterior circulation stroke (r = .76; P correlated for the left and the right hemispheric strokes (r = .83 and .81; P correlation between the baseline NIHSS score and the ischemic volume estimated by CTP. We confirmed that NIHSS is a reliable predictor of perfusion deficits in acute ischemic stroke. CTP allows fast imaging assessment in the hyperacute phase. The results highlight the importance of these diagnostic tools in the assessment of stroke severity and in acute decision-making. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  18. External Validation of the Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale Score for Predicting Pneumonia After Stroke Using Data From the China National Stroke Registry.

    Science.gov (United States)

    Zhang, Runhua; Ji, Ruijun; Pan, Yuesong; Jiang, Yong; Liu, Gaifen; Wang, Yilong; Wang, Yongjun

    2017-05-01

    Pneumonia is an important risk factor for mortality and morbidity after stroke. The Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale (ISAN) score was shown to be a useful tool for predicting stroke-associated pneumonia based on UK multicenter cohort study. We aimed to externally validate the score using data from the China National Stroke Registry (CNSR). Eligible patients with acute ischemic stroke (AIS) and intracerebral hemorrhage (ICH) in the CNSR from 2007 to 2008 were included. The area under the receiver operating characteristic (AUC) curve was used to evaluate discrimination. The Hosmer-Lemeshow goodness of fit test and Pearson correlation coefficient were performed to assess calibration of the model. A total of 19,333 patients (AIS = 14400; ICH = 4933) were included and the overall pneumonia rate was 12.7%. The AUC was .76 (95% confidence interval [CI]: .75-.78) for the subgroup of AIS and .70 (95% CI: .68-.72) for the subgroup of ICH. The Hosmer-Lemeshow test showed the ISAN score with the good calibration for AIS and ICH (P = .177 and .405, respectively). The plot of observed versus predicted pneumonia rates suggested higher correlation for patients with AIS than with ICH (Pearson correlation coefficient = .99 and .83, respectively). The ISAN score was a useful tool for predicting in-hospital pneumonia after acute stroke, especially for patients with AIS. Further validations need to be done in different populations. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  19. Premorbid functioning of patients with first-episode nonaffective psychosis: a comparison of deterioration in academic and social performance, and clinical correlates of Premorbid Adjustment Scale scores.

    Science.gov (United States)

    Monte, Ralph C; Goulding, Sandra M; Compton, Michael T

    2008-09-01

    Motivated by a previous study among male veterans [Allen, D.N., Frantom, L.V., Strauss, G.P., van Kammen, D.P., 2005. Differential patterns of premorbid academic and social deterioration in patients with schizophrenia. Schizophr. Res. 75, 389-397], the present analysis examined: (1) patterns of premorbid academic and social functioning during childhood, early adolescence, and late adolescence, and (2) associations between these premorbid functioning dimensions and a number of clinical variables. Data on premorbid functioning were collected using the Premorbid Adjustment Scale (PAS) in 95 hospitalized first-episode patients. Analyses were similar to those conducted by Allen and colleagues (2005). Deterioration was evident in both academic and social functioning from childhood to early adolescence, along with a pronounced/accelerated deterioration in academic functioning from early adolescence to late adolescence, occurring in both male and female patients. Age at onset of prodromal symptoms was predicted by childhood/early adolescent/late adolescent academic functioning scores, and age at onset of psychotic symptoms was significantly associated only with childhood academic functioning. Severity of negative symptoms was predicted by childhood and late adolescent social functioning scores, and severity of general psychopathology symptoms was predicted by late adolescent academic functioning, as well as childhood and late adolescent social functioning scores. Consistent with prior findings, deterioration in premorbid functioning appears to be more pronounced in the academic than social dimension of the PAS. Some PAS scores are predictive of ages at onset of prodrome/psychosis and severity of psychotic symptoms. Ongoing research on premorbid adjustment in schizophrenia may have implications for future prevention goals.

  20. Preliminary Design and Simulation of a Turbo Expander for Small Rated Power Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Roberto Capata

    2014-11-01

    Full Text Available Nowadays, the Organic Rankine Cycle (ORC system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.; from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW. Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc. or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.. These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo-expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar, imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen

  1. Catestatin, vasostatin, cortisol, temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale and visual analog scale for stress and pain behavior in dogs before and after ovariohysterectomy.

    Science.gov (United States)

    Srithunyarat, Thanikul; Höglund, Odd V; Hagman, Ragnvi; Olsson, Ulf; Stridsberg, Mats; Lagerstedt, Anne-Sofie; Pettersson, Ann

    2016-08-02

    The stress reaction induced by surgery and associated pain may be detrimental for patient recovery and should be minimized. The neuropeptide chromogranin A (CGA) has shown promise as a sensitive biomarker for stress in humans. Little is known about CGA and its derived peptides, catestatin (CST) and vasostatin (VS), in dogs undergoing surgery. The objectives of this study were to investigate and compare concentrations of CGA epitopes CST and VS, cortisol, body temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale (CMPS-SF) and visual analog scales (VAS) for stress and pain behavior in dogs before and after ovariohysterectomy. Thirty healthy privately owned female dogs admitted for elective ovariohysterectomy were included. Physical examination, CMPS-SF, pain behavior VAS, and stress behavior VAS were recorded and saliva and blood samples were collected before surgery, 3 h after extubation, and once at recall 7-15 days after surgery. Dogs were premedicated with morphine and received carprofen as analgesia for 7 days during the postoperative period. At 3 h after extubation, CMPS-SF and pain behavior VAS scores had increased (p stress behavior VAS scores, temperature, respiratory rate (p stress and pain changed in dogs subjected to ovariohysterectomy. To further evaluate CST and VS usefulness as pain biomarkers, studies on dogs in acute painful situations are warranted.

  2. Performance of four ischemic stroke prognostic scores in a Brazilian population.

    Science.gov (United States)

    Kuster, Gustavo W; Dutra, Lívia A; Brasil, Israel P; Pacheco, Evelyn P; Arruda, Márcio J C; Volcov, Cristiane; Domingues, Renan B

    2016-02-01

    Ischemic stroke (IS) prognostic scales may help clinicians in their clinical decisions. This study aimed to assess the performance of four IS prognostic scales in a Brazilian population. We evaluated data of IS patients admitted at Hospital Paulistano, a Joint Commission International certified primary stroke center. In-hospital mortality and modified Rankin score at discharge were defined as the outcome measures. The performance of National Institutes of Health Stroke Scale (NIHSS), Stroke Prognostication Using Age and NIHSS (SPAN-100), Acute Stroke Registry and Analysis of Lausanne (ASTRAL), and Totaled Health Risks in Vascular Events (THRIVE) were compared. Two hundred six patients with a mean ± SD age of 67.58 ± 15.5 years, being 55.3% male, were included. The four scales were significantly and independently associated functional outcome. Only THRIVE was associated with in-hospital mortality. With area under the curve THRIVE and NIHSS were the scales with better performance for functional outcome and THRIVE had the best performance for mortality. THRIVE showed the best performance among the four scales, being the only associated with in-hospital mortality.

  3. Performance of four ischemic stroke prognostic scores in a Brazilian population

    Directory of Open Access Journals (Sweden)

    Gustavo W. Kuster

    2016-02-01

    Full Text Available ABSTRACT Objective Ischemic stroke (IS prognostic scales may help clinicians in their clinical decisions. This study aimed to assess the performance of four IS prognostic scales in a Brazilian population. Method We evaluated data of IS patients admitted at Hospital Paulistano, a Joint Commission International certified primary stroke center. In-hospital mortality and modified Rankin score at discharge were defined as the outcome measures. The performance of National Institutes of Health Stroke Scale (NIHSS, Stroke Prognostication Using Age and NIHSS (SPAN-100, Acute Stroke Registry and Analysis of Lausanne (ASTRAL, and Totaled Health Risks in Vascular Events (THRIVE were compared. Results Two hundred six patients with a mean ± SD age of 67.58 ± 15.5 years, being 55.3% male, were included. The four scales were significantly and independently associated functional outcome. Only THRIVE was associated with in-hospital mortality. With area under the curve THRIVE and NIHSS were the scales with better performance for functional outcome and THRIVE had the best performance for mortality. Conclusion THRIVE showed the best performance among the four scales, being the only associated with in-hospital mortality.

  4. The relation of putamen nucleus 6-[18F]fluoro-L-m-tyrosine uptake to total Unified Parkinson's Disease Rating Scale scores

    International Nuclear Information System (INIS)

    Buchy, R.

    2002-01-01

    The contribution of dopaminergic deficiency in the striatum to the severity of locomotor disability in Parkinson's disease has been consistently shown with 6-[ 18 F]fluoro-L-DOPA in positron emission tomography. Recently, 6-[ 18 F]fluoro-L-m-tyrosine, an alternative tracer with similar distribution kinetics has been used to facilitate data analysis. Locomotor disability in Parkinson's disease can be measured using the Unified Parkinson's Disease Rating Scale. The Unified Parkinson's Disease Rating Scale was used in conjunction with 6-[ 18 F]fluoro-L-m-tyrosine -PET to clinically examine a group of five Parkinson's disease patients. An inverse relation similar to that previously demonstrated with 6-[ 18 F]fluoro-L-DOPA was found between the putamen nucleus 6-[ 18 F]fluoro-L-m-tyrosine influx constant and Unified Parkinson's Disease Rating Scale score. This finding suggests that like 6-[ 18 F]fluoro-L-m-tyrosine can be used to accurately measure the degree of locomotor disability caused by Parkinson's disease. (author)

  5. Measuring the impact of multiple sclerosis on psychosocial functioning: the development of a new self-efficacy scale.

    Science.gov (United States)

    Airlie, J; Baker, G A; Smith, S J; Young, C A

    2001-06-01

    To develop a scale to measure self-efficacy in neurologically impaired patients with multiple sclerosis and to assess the scale's psychometric properties. Cross-sectional questionnaire study in a clinical setting, the retest questionnaire returned by mail after completion at home. Regional multiple sclerosis (MS) outpatient clinic or the Clinical Trials Unit (CTU) at a large neuroscience centre in the UK. One hundred persons with MS attending the Walton Centre for Neurology and Neurosurgery and Clatterbridge Hospital, Wirral, as outpatients. Cognitively impaired patients were excluded at an initial clinic assessment. Patients were asked to provide demographic data and complete the self-efficacy scale along with the following validated scales: Hospital Anxiety and Depression Scale, Rosenberg Self-Esteem Scale, Impact, Stigma and Mastery and Rankin Scales. The Rankin Scale and Barthel Index were also assessed by the physician. A new 11-item self-efficacy scale was constructed consisting of two domains of control and personal agency. The validity of the scale was confirmed using Cronbach's alpha analysis of internal consistency (alpha = 0.81). The test-retest reliability of the scale over two weeks was acceptable with an intraclass correlation coefficient of 0.79. Construct validity was investigated using Pearson's product moment correlation coefficient resulting in significant correlations with depression (r= -0.52) anxiety (r =-0.50) and mastery (r= 0.73). Multiple regression analysis demonstrated that these factors accounted for 70% of the variance of scores on the self-efficacy scale, with scores on mastery, anxiety and perceived disability being independently significant. Assessment of the psychometric properties of this new self-efficacy scale suggest that it possesses good validity and reliability in patients with multiple sclerosis.

  6. Organic Rankine cycle for power recovery of exhaust flue gas

    International Nuclear Information System (INIS)

    Guo, Cong; Du, Xiaoze; Yang, Lijun; Yang, Yongping

    2015-01-01

    To study the effects of different working fluids on the performance of organic Rankine cycle (ORC), three working fluids, a mixture that matches with heat source, a mixture that matches with heat sink and a pure working fluid, are selected in this paper. Thermodynamic models were built in Matlab together with REFPROP, with which, the physical properties of the selected working fluids can be acquired. Heat source of the ORC system is the exhaust flue gas of boiler in a 240 MW pulverized coal-fired power plant. Some indicators such as thermal efficiency, inlet temperature of expander, superheat degree, mass flow, volumetric flow, and exergy destruction distribution, as well as the influence of recuperator are studied. The analytical results show that the mixture that matches with heat sink has the greatest efficiency and the mixture that matches with heat source has the lowest superheat degree. The rate of heat exchanged in recuperator to that in evaporator has a maximum value with evaporating pressure. There exists no optimal working fluid for all indicators (thermal efficiency, heat exchanger area, mass flow and volumetric flow etc.). An appropriate working fluid should be chosen by taking both investment cost and power generating benefits into account. The cost-benefit ratio of the proposed ORC plant was evaluated either. - Highlights: • Three types of working fluids are selected for ORC using exhaust flue gas. • The mixture that matches with heat sink has the greatest efficiency. • The mixture that matches with heat source has the lowest superheat degree. • There does not exist a working fluid that satisfies all the indicators

  7. Test-retest reliability at the item level and total score level of the Norwegian version of the Spinal Cord Injury Falls Concern Scale (SCI-FCS).

    Science.gov (United States)

    Roaldsen, Kirsti Skavberg; Måøy, Åsa Blad; Jørgensen, Vivien; Stanghelle, Johan Kvalvik

    2016-05-01

    Translation of the Spinal Cord Injury Falls Concern Scale (SCI-FCS), and investigation of test-retest reliability on item-level and total-score-level. Translation, adaptation and test-retest study. A specialized rehabilitation setting in Norway. Fifty-four wheelchair users with a spinal cord injury. The median age of the cohort was 49 years, and the median number of years after injury was 13. Interventions/measurements: The SCI-FCS was translated and back-translated according to guidelines. Individuals answered the SCI-FCS twice over the course of one week. We investigated item-level test-retest reliability using Svensson's rank-based statistical method for disagreement analysis of paired ordinal data. For relative reliability, we analyzed the total-score-level test-retest reliability with intraclass correlation coefficients (ICC2.1), the standard error of measurement (SEM), and the smallest detectable change (SDC) for absolute reliability/measurement-error assessment and Cronbach's alpha for internal consistency. All items showed satisfactory percentage agreement (≥69%) between test and retest. There were small but non-negligible systematic disagreements among three items; we recovered an 11-13% higher chance for a lower second score. There was no disagreement due to random variance. The test-retest agreement (ICC2.1) was excellent (0.83). The SEM was 2.6 (12%), and the SDC was 7.1 (32%). The Cronbach's alpha was high (0.88). The Norwegian SCI-FCS is highly reliable for wheelchair users with chronic spinal cord injuries.

  8. Extending Structural Analyses of the Rosenberg Self-Esteem Scale to Consider Criterion-Related Validity: Can Composite Self-Esteem Scores Be Good Enough?

    Science.gov (United States)

    Donnellan, M Brent; Ackerman, Robert A; Brecheen, Courtney

    2016-01-01

    Although the Rosenberg Self-Esteem Scale (RSES) is the most widely used measure of global self-esteem in the literature, there are ongoing disagreements about its factor structure. This methodological debate informs how the measure should be used in substantive research. Using a sample of 1,127 college students, we test the overall fit of previously specified models for the RSES, including a newly proposed bifactor solution (McKay, Boduszek, & Harvey, 2014 ). We extend previous work by evaluating how various latent factors from these structural models are related to a set of criterion variables frequently studied in the self-esteem literature. A strict unidimensional model poorly fit the data, whereas models that accounted for correlations between negatively and positively keyed items tended to fit better. However, global factors from viable structural models had similar levels of association with criterion variables and with the pattern of results obtained with a composite global self-esteem variable calculated from observed scores. Thus, we did not find compelling evidence that different structural models had substantive implications, thereby reducing (but not eliminating) concerns about the integrity of the self-esteem literature based on overall composite scores for the RSES.

  9. Improving the efficiency of heat supply systems on the basis of plants operating on organic Rankine cycle

    Science.gov (United States)

    Solomin, I. N.; Daminov, A. Z.; Sadykov, R. A.

    2017-11-01

    Results of experimental and analytical studies of the plant main element - plant turbomachine (turbo-expander) operating on organic Rankine cycle were obtained for facilities of the heat supply systems of small-scale power generation. At simultaneous mathematical modeling and experimental studies it was found that the best working medium to be used in the turbomachines of these plants is Freon R245fa which has the most suitable calorimetric properties to be used in the cycle. The mathematical model of gas flow in the turbomachine was developed. The main engineering dependencies to calculate the optimal design parameters of the turbomachine were obtained. The engineering problems of providing the minimum axial size of the turbomachine impeller were solved and the main design elements were unified.

  10. Application of Biomass from Palm Oil Mill for Organic Rankine Cycle to Generate Power in North Sumatera Indonesia

    Science.gov (United States)

    Nur, T. B.; Pane, Z.; Amin, M. N.

    2017-03-01

    Due to increasing oil and gas demand with the depletion of fossil resources in the current situation make efficient energy systems and alternative energy conversion processes are urgently needed. With the great potential of resources in Indonesia, make biomass has been considered as one of major potential fuel and renewable resource for the near future. In this paper, the potential of palm oil mill waste as a bioenergy source has been investigated. An organic Rankine cycle (ORC) small scale power plant has been preliminary designed to generate electricity. The working fluid candidates for the ORC plant based on the heat source temperature domains have been investigated. The ORC system with a regenerator has higher thermal efficiency than the basic ORC system. The study demonstrates the technical feasibility of ORC solutions in terms of resources optimizations and reducing of greenhouse gas emissions.

  11. Parametric optimization and range analysis of Organic Rankine Cycle for binary-cycle geothermal plant

    International Nuclear Information System (INIS)

    Wang, Xing; Liu, Xiaomin; Zhang, Chuhua

    2014-01-01

    Highlights: • Optimal level constitution of parameters for ORC system was obtained. • Order of system parameters’ sensitivity to the performance of ORC was revealed. • Evaporating temperature had significant effect on performance of ORC system. • Superheater had little effect on performance of ORC system. - Abstract: In this study, a thermodynamic model of Organic Rankine Cycle (ORC) system combined with orthogonal design is proposed. The comprehensive scoring method was adopted to obtain a comprehensive index to evaluate both of the thermodynamic performance and economic performance. The optimal level constitution of system parameters which improves the thermodynamic and economic performance of ORC system is provided by analyzing the result of orthogonal design. The range analysis based on orthogonal design is adopted to determine the sensitivity of system parameters to the net power output of ORC system, thermal efficiency, the SP factor of radial inflow turbine, the power decrease factor of the pump and the total heat transfer capacity. The results show that the optimal level constitution of system parameters is determined as the working fluid of R245fa, the super heating temperature of 10 °C, the pinch temperature difference in evaporator and condenser of 5 °C, the evaporating temperature of 65 °C, the isentropic efficiency for the pump of 0.75 and the isentropic efficiency of radial inflow turbine of 0.85. The order of system parameters’ sensitivity to the comprehensive index of orthogonal design is evaporating temperature > isentropic efficiency of radial inflow turbine > the working fluid > the pinch temperature difference of the evaporator and the condenser > isentropic efficiency of cycle pump > the super heating temperature. This study provides useful references for selecting main controlled parameters in the optimal design of ORC system

  12. Sentiment analysis methods for understanding large-scale texts: a case for using continuum-scored words and word shift graphs

    Directory of Open Access Journals (Sweden)

    Andrew J Reagan

    2017-10-01

    Full Text Available Abstract The emergence and global adoption of social media has rendered possible the real-time estimation of population-scale sentiment, an extraordinary capacity which has profound implications for our understanding of human behavior. Given the growing assortment of sentiment-measuring instruments, it is imperative to understand which aspects of sentiment dictionaries contribute to both their classification accuracy and their ability to provide richer understanding of texts. Here, we perform detailed, quantitative tests and qualitative assessments of 6 dictionary-based methods applied to 4 different corpora, and briefly examine a further 20 methods. We show that while inappropriate for sentences, dictionary-based methods are generally robust in their classification accuracy for longer texts. Most importantly they can aid understanding of texts with reliable and meaningful word shift graphs if (1 the dictionary covers a sufficiently large portion of a given text’s lexicon when weighted by word usage frequency; and (2 words are scored on a continuous scale.

  13. Comparisons of American, Israeli, Italian and Mexican physicians and nurses on the total and factor scores of the Jefferson scale of attitudes toward physician-nurse collaborative relationships.

    Science.gov (United States)

    Hojat, Mohammadreza; Gonnella, Joseph S; Nasca, Thomas J; Fields, Sylvia K; Cicchetti, Americo; Lo Scalzo, Alessandra; Taroni, Francesco; Amicosante, Anna Maria Vincenza; Macinati, Manuela; Tangucci, Massimo; Liva, Carlo; Ricciardi, Gualtiero; Eidelman, Shmuel; Admi, Hanna; Geva, Hana; Mashiach, Tanya; Alroy, Gideon; Alcorta-Gonzalez, Adelina; Ibarra, David; Torres-Ruiz, Antonio

    2003-05-01

    This cross-cultural study was designed to compare the attitudes of physicians and nurses toward physician-nurse collaboration in the United States, Israel, Italy and Mexico. Total participants were 2522 physicians and nurses who completed the Jefferson Scale of Attitudes Toward Physician-Nurse Collaboration (15 Likert-type items, (Hojat et al., Evaluation and the Health Professions 22 (1999a) 208; Nursing Research 50 (2001) 123). They were compared on the total scores and four factors of the Jefferson Scale (shared education and team work, caring as opposed to curing, nurses, autonomy, physicians' dominance). Results showed inter- and intra-cultural similarities and differences among the study groups providing support for the social role theory (Hardy and Conway, Role Theory: Perspectives for Health Professionals, Appelton-Century-Crofts, New York, 1978) and the principle of least interest (Waller and Hill, The Family: A Dynamic Interpretation, Dryden, New York, 1951) in inter-professional relationships. Implications for promoting physician-nurse education and inter-professional collaboration are discussed.

  14. Validation of the DRAGON Score in a Chinese Population to Predict Functional Outcome of Intravenous Thrombolysis-Treated Stroke Patients.

    Science.gov (United States)

    Zhang, Xinmiao; Liao, Xiaoling; Wang, Chunjuan; Liu, Liping; Wang, Chunxue; Zhao, Xingquan; Pan, Yuesong; Wang, Yilong; Wang, Yongjun

    2015-08-01

    The DRAGON score predicts functional outcome of ischemic stroke patients treated with intravenous thrombolysis. Our aim was to evaluate its utility in a Chinese stroke population. Patients with acute ischemic stroke treated with intravenous thrombolysis were prospectively registered in the Thrombolysis Implementation and Monitor of acute ischemic Stroke in China. We excluded patients with basilar artery occlusion and missing data, leaving 970 eligible patients. We calculated the DRAGON score, and the clinical outcome was measured by the modified Rankin Scale at 3 months. Model discrimination was quantified by calculating the C statistic. Calibration was assessed using Pearson correlation coefficient. The C statistic was .73 (.70-.76) for good outcome and .75 (.70-.79) for miserable outcome. Proportions of patients with good outcome were 94%, 83%, 70%, and 0% for 0 to 1, 2, 3, and 8 to 10 score points, respectively. Proportions of patients with miserable outcome were 0%, 3%, 9%, and 50% for 0 to 1, 2, 3, and 8 to 10 points, respectively. There was high correlation between predicted and observed probability of 3-month favorable and miserable outcome in the external validation cohort (Pearson correlation coefficient, .98 and .98, respectively, both P DRAGON score showed good performance to predict functional outcome after tissue-type plasminogen activator treatment in the Chinese population. This study demonstrated the accuracy and usability of the DRAGON score in the Chinese population in daily practice. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  15. Experimental Study of a Low-Temperature Power Generation System in an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Mu, Yongchao; Zhang, Yufeng; Deng, Na

    2015-01-01

    This paper presents a new power generation system under the principle of organic Rankine cycle which can generate power with a low-temperature heat source. A prototype was built to investigate the proposed system. In the prototype, an air screw compressor was converted into an expander and used...... as the engine of the power generator. The style of the preheater was a shell and tube heat exchanger, which could provide a long path for the working fluid. A flooded heat exchanger with a high heat transfer coefficient was taken as the evaporator. R134a was used as working fluid for the Rankine cycle......, the average isentropic efficiency of the screw expander was 68%, and the efficiency of power generation varies from 1.2 to 4.56%. The highest value of thermodynamical perfectness was 29.06%. It can be concluded that organic Rankine cycle could be competitive for recovering low-temperature heat source...

  16. A review of the use of organic Rankine cycle power systems for maritime applications

    DEFF Research Database (Denmark)

    Mondejar, M. E.; Andreasen, J. G.; Pierobon, L.

    2018-01-01

    combustion, geothermal reservoirs, and waste heat from industrial processes. However, its economic feasibility has not yet been demonstrated for marine applications. This paper aims at evaluating the potential of using organic Rankine cycle systems for waste heat recovery aboard ships. The suitable vessels......Diesel engines are by far the most common means of propulsion aboard ships. It is estimated that around half of their fuel energy consumption is dissipated as low-grade heat. The organic Rankine cycle technology is a well-established solution for the energy conversion of thermal power from biomass...... in order to tackle the challenges limiting a widespread use of this technology in currently operating vessels and new-buildings. The results indicate that organic Rankine cycle units recovering heat from the exhaust gases of engines using low-sulfur fuels could yield fuel savings between 10% and 15%....

  17. Power generation and heating performances of integrated system of ammonia–water Kalina–Rankine cycle

    International Nuclear Information System (INIS)

    Zhang, Zhi; Guo, Zhanwei; Chen, Yaping; Wu, Jiafeng; Hua, Junye

    2015-01-01

    Highlights: • Integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) is investigated. • Ammonia–water Rankine cycle is operated for cogenerating room heating-water in winter. • Kalina cycle with higher efficiency is operated for power generation in other seasons. • Power recovery efficiency accounts thermal efficiency and waste heat absorbing ratio. • Heating water with 70 °C and capacity of 55% total reclaimed heat load is cogenerated. - Abstract: An integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) for power generation and heating is introduced. The Kalina cycle has large temperature difference during evaporation and small one during condensation therefore with high thermal efficiency for power generation, while the ammonia–water Rankine cycle has large temperature difference during condensation as well as evaporation, thus it can be adopted to generate heating-water as a by-product in winter. The integrated system is based on the Kalina cycle and converted to the Rankine cycle with a set of valves. The performances of the AWKRC system in different seasons with corresponding cycle loops were studied and analyzed. When the temperatures of waste heat and cooling water are 300 °C and 25 °C respectively, the thermal efficiency and power recovery efficiency of Kalina cycle are 20.9% and 17.4% respectively in the non-heating seasons, while these efficiencies of the ammonia–water Rankine cycle are 17.1% and 13.1% respectively with additional 55.3% heating recovery ratio or with comprehensive efficiency 23.7% higher than that of the Kalina cycle in heating season

  18. Self perception score from zero to ten correlates well with standardized scales of adolescent self esteem, body dissatisfaction, eating disorders risk, depression, and anxiety.

    Science.gov (United States)

    O'Dea, Jennifer A

    2009-01-01

    The ability to quickly and reliably assess mental health status would assist health workers, educators and youth workers to provide appropriate early intervention for adolescents. To investigate the validity of a simple self perception score out of ten by correlating the self perception scores of adolescents from a normal, community sample of adolescents with their scores on standardized mental health measures. Study group was 470 early adolescent students aged 11.0-14.5 years from grades 7 and 8 in two secondary schools. Self perception was self reported using a score of zero to ten points, and the scores were then correlated with scores on the Harter Self Perception Profile, Beck Junior Depression, Speilberger State and Trait Anxiety and the Eating Disorders Inventory. A High Risk group (self perception adolescents also had poor self esteem and risk for depression, anxiety, and eating disorders. Self perception scores correlated positively with self esteem and self concept subscales and it was negatively associated with depression, state and trait anxiety, and EDI scores. Of the 15.1% high risk adolescents in the overall sample, 78% scored below the group average on the mean of all Harter Self Concept scores; 70% scored above average for Beck Depression; 64% and 74% scored above average on Speilberger State/Trait Anxiety respectively; 80% scored higher than the average on the group mean EDI. A self perception score from zero to ten can be a simple and accurate way of gaining an initial insight into the current mental health status of adolescents.

  19. Magnetic Resonance Imaging-DRAGON score: 3-month outcome prediction after intravenous thrombolysis for anterior circulation stroke.

    Science.gov (United States)

    Turc, Guillaume; Apoil, Marion; Naggara, Olivier; Calvet, David; Lamy, Catherine; Tataru, Alina M; Méder, Jean-François; Mas, Jean-Louis; Baron, Jean-Claude; Oppenheim, Catherine; Touzé, Emmanuel

    2013-05-01

    The DRAGON score, which includes clinical and computed tomographic scan parameters, showed a high specificity to predict 3-month outcome in patients with acute ischemic stroke treated by intravenous tissue plasminogen activator. We adapted the score for patients undergoing MRI as the first-line diagnostic tool. We reviewed patients with consecutive anterior circulation ischemic stroke treated ≤ 4.5 hour by intravenous tissue plasminogen activator between 2003 and 2012 in our center, where MRI is systematically implemented as first-line diagnostic work-up. We derived the MRI-DRAGON score keeping all clinical parameters of computed tomography-DRAGON (age, initial National Institutes of Health Stroke Scale and glucose level, prestroke handicap, onset to treatment time), and considering the following radiological variables: proximal middle cerebral artery occlusion on MR angiography instead of hyperdense middle cerebral artery sign, and diffusion-weighted imaging Alberta Stroke Program Early Computed Tomography Score (DWI ASPECTS) ≤ 5 instead of early infarct signs on computed tomography. Poor 3-month outcome was defined as modified Rankin scale >2. We calculated c-statistics as a measure of predictive ability and performed an internal cross-validation. Two hundred twenty-eight patients were included. Poor outcome was observed in 98 (43%) patients and was significantly associated with all parameters of the MRI-DRAGON score in multivariate analysis, except for onset to treatment time (nonsignificant trend). The c-statistic was 0.83 (95% confidence interval, 0.78-0.88) for poor outcome prediction. All patients with a MRI-DRAGON score ≤ 2 (n=22) had a good outcome, whereas all patients with a score ≥ 8 (n=11) had a poor outcome. The MRI-DRAGON score is a simple tool to predict 3-month outcome in acute stroke patients screened by MRI then treated by intravenous tissue plasminogen activator and may help for therapeutic decision.

  20. Perme Intensive Care Unit Mobility Score and ICU Mobility Scale: translation into Portuguese and cross-cultural adaptation for use in Brazil

    Science.gov (United States)

    Kawaguchi, Yurika Maria Fogaça; Nawa, Ricardo Kenji; Figueiredo, Thais Borgheti; Martins, Lourdes; Pires-Neto, Ruy Camargo

    2016-01-01

    ABSTRACT Objective: To translate the Perme Intensive Care Unit Mobility Score and the ICU Mobility Scale (IMS) into Portuguese, creating versions that are cross-culturally adapted for use in Brazil, and to determine the interobserver agreement and reliability for both versions. Methods: The processes of translation and cross-cultural validation consisted in the following: preparation, translation, reconciliation, synthesis, back-translation, review, approval, and pre-test. The Portuguese-language versions of both instruments were then used by two researchers to evaluate critically ill ICU patients. Weighted kappa statistics and Bland-Altman plots were used in order to verify interobserver agreement for the two instruments. In each of the domains of the instruments, interobserver reliability was evaluated with Cronbach's alpha coefficient. The correlation between the instruments was assessed by Spearman's correlation test. Results: The study sample comprised 103 patients-56 (54%) of whom were male-with a mean age of 52 ± 18 years. The main reason for ICU admission (in 44%) was respiratory failure. Both instruments showed excellent interobserver agreement (κ > 0.90) and reliability (α > 0.90) in all domains. Interobserver bias was low for the IMS and the Perme Score (−0.048 ± 0.350 and −0.06 ± 0.73, respectively). The 95% CIs for the same instruments ranged from −0.73 to 0.64 and −1.50 to 1.36, respectively. There was also a strong positive correlation between the two instruments (r = 0.941; p < 0.001). Conclusions: In their versions adapted for use in Brazil, both instruments showed high interobserver agreement and reliability. PMID:28117473

  1. Perme Intensive Care Unit Mobility Score and ICU Mobility Scale: translation into Portuguese and cross-cultural adaptation for use in Brazil

    Directory of Open Access Journals (Sweden)

    Yurika Maria Fogaça Kawaguchi

    Full Text Available ABSTRACT Objective: To translate the Perme Intensive Care Unit Mobility Score and the ICU Mobility Scale (IMS into Portuguese, creating versions that are cross-culturally adapted for use in Brazil, and to determine the interobserver agreement and reliability for both versions. Methods: The processes of translation and cross-cultural validation consisted in the following: preparation, translation, reconciliation, synthesis, back-translation, review, approval, and pre-test. The Portuguese-language versions of both instruments were then used by two researchers to evaluate critically ill ICU patients. Weighted kappa statistics and Bland-Altman plots were used in order to verify interobserver agreement for the two instruments. In each of the domains of the instruments, interobserver reliability was evaluated with Cronbach's alpha coefficient. The correlation between the instruments was assessed by Spearman's correlation test. Results: The study sample comprised 103 patients-56 (54% of whom were male-with a mean age of 52 ± 18 years. The main reason for ICU admission (in 44% was respiratory failure. Both instruments showed excellent interobserver agreement ( > 0.90 and reliability ( > 0.90 in all domains. Interobserver bias was low for the IMS and the Perme Score (−0.048 ± 0.350 and −0.06 ± 0.73, respectively. The 95% CIs for the same instruments ranged from −0.73 to 0.64 and −1.50 to 1.36, respectively. There was also a strong positive correlation between the two instruments (r = 0.941; p < 0.001. Conclusions: In their versions adapted for use in Brazil, both instruments showed high interobserver agreement and reliability.

  2. The use of brain CT Scan in craniocerebral trauma with Glasgow coma scale scores of 13 – 15 in Dr. Cipto Mangunkusumo Hospital 1999-2001

    Directory of Open Access Journals (Sweden)

    Jofizal Jannis

    2004-09-01

    Full Text Available There is still a controversy among the neurologists whether brain CT scan must be performed on the mild head trauma patients. This study was executed to find out the correlation between the brain CT scan image findings and its clinical impairment among the mild head trauma patients with Glasgow coma scale (GCS score of 13 to 15. The study was a retrospective study by analyzing the uniform medical records of the head trauma patients hospitalized at the Neurology ward of Dr. Cipto Mangunkusumo Hospital within the period of 1999 to 2001. During that period 1,663 patients were hospitalized due to head trauma, and 1,166 of them (70.1 % were suffered from mild head trauma patients with GCS score of 13-15. Among those with brain CT scan examinations (N: 271, the neurological abnormalities were found on 144 (53.1% of patients, consisted of cerebral edema (11,4%, intracerebral hemorrhage (5.5%, epidural hemorrhage (16.2%, subdural hemorrhage (18.1%, subarachnoid hemorrhage (5.5%, and combination (13.8%. The further analysis showed that cranial nerves disturbance, amnesia, loss of conciousness for more than 10 minutes, and vomiting are significantly correlated to the brain CT scan abnormality. Combination of the above four clinical signs and symptoms have sensitivity of 90 % in predicting brain insults. This findings may be used as a simple set of clinical criteria for identifying mild head trauma patients who need undergo CT scan examination. (Med J Indones 2004; 13: 156-60 Keywords: mild head injury, brain CT scan

  3. Equation of State Selection for Organic Rankine Cycle Modeling Under Uncertainty

    DEFF Research Database (Denmark)

    Frutiger, Jerome; O'Connell, John; Abildskov, Jens

    In recent years there has been a great interest in the design and selection of working fluids for low-temperature Organic Rankine Cycles (ORC), to efficiently produce electrical power from waste heat from chemical engineering applications, as well as from renewable energy sources such as biomass...... cycle, all influence the model output uncertainty. The procedure is highlighted for an ORC for with a low-temperature heat source from exhaust gas from a marine diesel engine.[1] Saleh B, Koglbauer G, Wendland M, Fischer J. Working fluids for lowtemperature organic Rankine cycles. Energy 2007...

  4. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

    DEFF Research Database (Denmark)

    Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

    2016-01-01

    Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...

  5. Simultaneous heat integration and techno-economic optimization of Organic Rankine Cycle (ORC) for multiple waste heat stream recovery

    International Nuclear Information System (INIS)

    Yu, Haoshui; Eason, John; Biegler, Lorenz T.; Feng, Xiao

    2017-01-01

    In the past decades, the Organic Rankine Cycle (ORC) has become a promising technology for low and medium temperature energy utilization. In refineries, there are usually multiple waste heat streams to be recovered. From a safety and controllability perspective, using an intermedium (hot water) to recover waste heat before releasing heat to the ORC system is more favorable than direct integration. The mass flowrate of the intermediate hot water stream determines the amount of waste heat recovered and the final hot water temperature affects the thermal efficiency of ORC. Both, in turn, exert great influence on the power output. Therefore, the hot water mass flowrate is a critical decision variable for the optimal design of the system. This study develops a model for techno-economic optimization of an ORC with simultaneous heat recovery and capital cost optimization. The ORC is modeled using rigorous thermodynamics with the concept of state points. The task of waste heat recovery using the hot water intermedium is modeled using the Duran-Grossmann model for simultaneous heat integration and process optimization. The combined model determines the optimal design of an ORC that recovers multiple waste heat streams in a large scale background process using an intermediate heat transfer stream. In particular, the model determines the optimal heat recovery approach temperature (HRAT), the utility load of the background process, and the optimal operating conditions of the ORC simultaneously. The effectiveness of this method is demonstrated with a case study that uses a refinery as the background process. Sensitivity of the optimal solution to the parameters (electricity price, utility cost) is quantified in this paper. - Highlights: • A new model for Organic Rankine cycle design optimization is presented. • Process heat integration and ORC are considered simultaneously. • Rigorous equation oriented models of the ORC are used for accurate results. • Impact of working

  6. A thermodynamic analysis of waste heat recovery from reciprocating engine power plants by means of Organic Rankine Cycles

    International Nuclear Information System (INIS)

    Uusitalo, Antti; Honkatukia, Juha; Turunen-Saaresti, Teemu; Larjola, Jaakko

    2014-01-01

    Organic Rankine Cycle (ORC) is a Rankine cycle using organic fluid as the working fluid instead of water and steam. The ORC process is a feasible choice in waste heat recovery applications producing electricity from relatively low-temperature waste heat sources or in applications having a rather low power output. Utilizing waste heat from a large high-efficiency reciprocating engine power plant with ORC processes is studied by means of computations. In addition to exhaust gas heat recovery, this study represents and discusses an idea of directly replacing the charge air cooler (CAC) of a large turbocharged engine with an ORC evaporator to utilize the charge air heat in additional power production. A thermodynamic analysis for ORCs was carried out with working fluids toluene, n-pentane, R245fa and cyclohexane. The effect of different ORC process parameters on the process performance are presented and analyzed in order to investigate the heat recovery potential from the exhaust gas and charge air. A simplified feasibility consideration is included by comparing the ratio of the theoretical heat transfer areas needed and the obtained power output from ORC processes. The greatest potential is related to the exhaust gas heat recovery, but in addition also the lower temperature waste heat streams could be utilized to boost the electrical power of the engine power plant. A case study for a large-scale gas-fired engine was carried out showing that the maximum power increase of 11.4% was obtained from the exhaust gas and 2.4% from the charge air heat. - Highlights: • Waste heat recovery potential of reciprocating engines was studied. • Thermodynamic optimization for ORCs was carried out with different fluids. • The utilization of exhaust gas and charge air heat is presented and discussed. • Simplified economic feasibility study was included in the analysis. • Power increase of 11.4% was obtained from exhaust gas and 2.4% from charge air

  7. AP Potential™ Expectancy Tables Based on PSAT/NMSQT® and SAT® Scores on the 2015-16 Redesigned Scales. Statistical Report 2016-2

    Science.gov (United States)

    Ewing, Maureen; Wyatt, Jeffrey N.; Smith, Kara

    2016-01-01

    Historically, AP Potential™ has used PSAT/NMSQT® scores to identify students who are likely to earn a 3 or higher on a specific AP® Exam--based on research showing moderate to strong relationships between PSAT/NMSQT scores and AP Exam scores (Camara & Millsap, 1998; Ewing, Camara & Millsap, 2006; Zhang, Patel & Ewing, 2014a). For most…

  8. AP Potential Expectancy Tables Based on PSAT/NMSQT and SAT Scores on the 2015-16 Redesigned Scales Using Final Concordance Tables. Statistical Report

    Science.gov (United States)

    Ewing, Maureen; Wyatt, Jeff

    2017-01-01

    Historically, AP Potential™ has used PSAT/NMSQT® scores to identify students who are likely to earn a 3 or higher on a specific AP Exam based on research showing moderate to strong relationships between PSAT/NMSQT scores and AP Exam scores (Camara & Millsap, 1998; Ewing, Camara, & Millsap, 2006; Zhang, Patel, & Ewing, 2014a). For most…

  9. Multiple regression models for the prediction of the maximum obtainable thermal efficiency of organic Rankine cycles

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Wronski, Jorrit

    2014-01-01

    Much attention is focused on increasing the energy efficiency to decrease fuel costs and CO2 emissions throughout industrial sectors. The ORC (organic Rankine cycle) is a relatively simple but efficient process that can be used for this purpose by converting low and medium temperature waste heat ...

  10. Constrained multi-objective optimization of radial expanders in organic Rankine cycles by firefly algorithm

    International Nuclear Information System (INIS)

    Bahadormanesh, Nikrouz; Rahat, Shayan; Yarali, Milad

    2017-01-01

    Highlights: • A multi-objective optimization for radial expander in Organic Rankine Cycles is implemented. • By using firefly algorithm, Pareto front based on the size of turbine and thermal efficiency is produced. • Tension and vibration constrains have a significant effect on optimum design points. - Abstract: Organic Rankine Cycles are viable energy conversion systems in sustainable energy systems due to their compatibility with low-temperature heat sources. In the present study, one dimensional model of radial expanders in conjunction with a thermodynamic model of organic Rankine cycles is prepared. After verification, by defining thermal efficiency of the cycle and size parameter of a radial turbine as the objective functions, a multi-objective optimization was conducted regarding tension and vibration constraints for 4 different organic working fluids (R22, R245fa, R236fa and N-Pentane). In addition to mass flow rate, evaporator temperature, maximum pressure of cycle and turbo-machinery design parameters are selected as the decision variables. Regarding Pareto fronts, by a little increase in size of radial expanders, it is feasible to reach high efficiency. Moreover, by assessing the distribution of decision variables, the variables that play a major role in trending between the objective functions are found. Effects of mechanical and vibration constrains on optimum decision variables are investigated. The results of optimization can be considered as an initial values for design of radial turbines for Organic Rankine Cycles.

  11. Technical and economical feasibility of the Rankine compression gas turbine (RCG)

    NARCIS (Netherlands)

    Ouwerkerk, H.; Lange, de H.C.

    2006-01-01

    The Rankine compression gas turbine (RCG) is a new type of combined cycle, i.e. combined steam and gas turbine installation, that returns all shaft power on one free power turbine. The novelty of the RCG is that the steam turbine drives the compressor of the gas turbine cycle. This way, the turbine

  12. Performance analysis of different organic Rankine cycle configurations on board liquefied natural gas-fuelled vessels

    DEFF Research Database (Denmark)

    Baldasso, Enrico; Andreasen, Jesper Graa; Meroni, Andrea

    2017-01-01

    Gas-fuelled shipping is expected to increase significantly in the coming years. Similarly, much effort is devoted to the study of waste heat recovery systems to be implemented on board ships. In this context, the organic Rankine cycle (ORC) technology is considered one of the most promising...

  13. A thermodynamic study of waste heat recovery from GT-MHR using organic Rankine cycles

    International Nuclear Information System (INIS)

    Yari, Mortaza; Mahmoudi, S.M.S.

    2011-01-01

    This paper presents an investigation on the utilization of waste heat from a gas turbine-modular helium reactor (GT-MHR) using different arrangements of organic Rankine cycles (ORCs) for power production. The considered organic Rankine cycles were: simple organic Rankine cycle (SORC), ORC with internal heat exchanger (HORC) and regenerative organic Rankine cycle (RORC). The performances of the combined cycles were studied from the point of view of first and second-laws of thermodynamics. Individual models were developed for each component and the effects of some important parameters such as compressor pressure ratio, turbine inlet temperature, and evaporator and environment temperatures on the efficiencies and on the exergy destruction rate were studied. Finally the combined cycles were optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on the identical operating conditions for the GT-MHR cycle, a comparison between the three combined cycles and a simple GT-MHR cycle is also were made. This comparison was also carried out from the point of view of economics. The GT-MHR/SORC combined cycle proved to be the best among all the cycles from the point of view of both thermodynamics and economics. The efficiency of this cycle was about 10% higher than that of GT-MHR alone. (orig.)

  14. Design of organic Rankine cycle power systems accounting for expander performance

    DEFF Research Database (Denmark)

    La Seta, Angelo; Andreasen, Jesper Graa; Pierobon, Leonardo

    2015-01-01

    Organic Rankine cycle power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. Its design process and efficiency estimation are particularly challenging due...

  15. Conservative treatment of soft tissue sarcomas of the extremities. Functional evaluation with LENT-SOMA scales and the Enneking score; Traitement conservateur des sarcomes des tissus mous des membres. Evaluation du resultat fonctionnel selon l'echelle LENT-SOMA et le score de Enneking

    Energy Technology Data Exchange (ETDEWEB)

    Tawfiq, N.; Lagarde, P.; Thomas, L.; Kantor, G. [Institut Bergonie, Centre Regional de Lutte Contre le Cancer, Service de Radiotherapie, 33 - Bordeaux (France); Stockle, E. [Institut Bergonie, Centre Regional de Lutte Contre le Cancer, Service de Chirurgie, 33 - Bordeaux (France); Bui, B.N. [Institut Bergonie, Centre Regional de Lutte Contre le Cancer, Service d' Oncologie Medicale, 33 - Bordeaux (France)

    2000-12-01

    Objective. - The aim of this prospective study is the feasibility of late effects assessment by LENT-SOMA scales after conservative treatment of soft tissue sarcomas of the extremities and a comparison with the functional evaluation by the Enneking score. Patients and methods. - During the systematic follow-up consultations, a series of 32 consecutive patients was evaluated in terms of late effects by LENT SOMA scales and functional results by the Enneking score. The median time after treatment was 65 months. The treatment consisted of conservative surgery (all cases) followed by radiation therapy (29 cases), often combined with adjuvant therapy (12 concomitant radio-chemotherapy association cases out of 14). The assessment of the toxicity was retrospective for acute effects and prospective for the following late tissue damage: skin/subcutaneous tissues, muscles/soft tissues and peripheral nerves. Results. -According to the Enneking score, the global score for the overall series was high (24/30) despite four the scores zero for the psychological acceptance. According to LENT SOMA scales, a low rate of severe sequelae (grade 3-4) was observed. The occurrence of high-grade sequelae and their functional consequences were not correlated with quality of exeresis, dose of radiotherapy or use of concomitant chemotherapy. A complementarity was observed between certain factors of the Enneking score and some criteria of the LENTSOMA scales, especially of muscles/soft tissues. Conclusion. -The good quality of functional results was confirmed by the two mean scoring systems for late normal tissue damage. The routine use of LENT-SOMA seems to be more time consuming than the Enneking score (mean time of scoring: 1 3 versus five minutes). The LENT-SOMA scales are aimed at a detailed description of late toxicity and sequelae while the Enneking score provides a more global evaluation, including the psychological acceptance of treatment. The late effects assessment by the LENT

  16. Perme Intensive Care Unit Mobility Score and ICU Mobility Scale: translation into Portuguese and cross-cultural adaptation for use in Brazil.

    Science.gov (United States)

    Kawaguchi, Yurika Maria Fogaça; Nawa, Ricardo Kenji; Figueiredo, Thais Borgheti; Martins, Lourdes; Pires-Neto, Ruy Camargo

    2016-01-01

    To translate the Perme Intensive Care Unit Mobility Score and the ICU Mobility Scale (IMS) into Portuguese, creating versions that are cross-culturally adapted for use in Brazil, and to determine the interobserver agreement and reliability for both versions. The processes of translation and cross-cultural validation consisted in the following: preparation, translation, reconciliation, synthesis, back-translation, review, approval, and pre-test. The Portuguese-language versions of both instruments were then used by two researchers to evaluate critically ill ICU patients. Weighted kappa statistics and Bland-Altman plots were used in order to verify interobserver agreement for the two instruments. In each of the domains of the instruments, interobserver reliability was evaluated with Cronbach's alpha coefficient. The correlation between the instruments was assessed by Spearman's correlation test. The study sample comprised 103 patients-56 (54%) of whom were male-with a mean age of 52 ± 18 years. The main reason for ICU admission (in 44%) was respiratory failure. Both instruments showed excellent interobserver agreement ( > 0.90) and reliability ( > 0.90) in all domains. Interobserver bias was low for the IMS and the Perme Score (-0.048 ± 0.350 and -0.06 ± 0.73, respectively). The 95% CIs for the same instruments ranged from -0.73 to 0.64 and -1.50 to 1.36, respectively. There was also a strong positive correlation between the two instruments (r = 0.941; p composta por 103 pacientes, sendo a maioria homens (n = 56; 54%), com média de idade = 52 ± 18 anos. O principal motivo de internação nas UTIs foi insuficiência respiratória (em 44%). Os dois instrumentos apresentaram excelente concordância interobservador (> 0,90) e confiabilidade ( > 0,90) em todos os domínios. Constatou-se um baixo viés interobservador na EMU e no Perme Escore (-0,048 ± 0,350 e -0,06 ± 0,73, respectivamente). Os IC95% para os mesmos instrumentos variaram

  17. Energy efficiency analysis of Organic Rankine Cycles with scroll expanders for cogenerative applications

    International Nuclear Information System (INIS)

    Clemente, Stefano; Micheli, Diego; Reini, Mauro; Taccani, Rodolfo

    2012-01-01

    Highlights: ► We present an ORC model composed of a scroll 1D model and a cycle thermodynamic one. ► High-series production components from HVAC field are considered to reduce costs. ► Couplings of the micro-CHP with low-temperature heat sources are analyzed. ► Small and low-cost CHP systems with acceptable electrical efficiency are realizable. ► Higher electrical efficiency are possible modifying the scroll geometry. -- Abstract: Small scale Organic Rankine Cycle (ORC) systems has been the object of a large number of studies in the last decade, because of their suitability for energy recovery and cogenerative applications. The paper presents an ORC numerical model and its applications to two different case studies; the code has been obtained by combining a one-dimensional model of a scroll machine and a thermodynamic model of a whole ORC system. Series production components, such as scroll compressors, from HVAC field, have been first considered in order to reduce costs, because this is a critical issue for small scale energy recovery and cogeneration systems. The detailed model of the scroll machine is capable to calculate the performances of both a compressor and an expander, as function of the geometry of the device and of the working fluid. The model has been first tested and validated by comparing its outputs with experimental tests on a commercial scroll compressor, then used to calculate the working curves of commercial scroll machines originally designed as compressors in the HVAC field, but operating as expanders. The model of the expander has been then integrated in the thermodynamic model of the ORC system. A series of comparisons have been carried out in order to evaluate how the performances are influenced by cycle parameters, scroll geometry and working fluid for different applications. The results confirm the feasibility of small scale CHP systems with acceptable electrical efficiency, taking into account the low-temperature thermal source

  18. PROMIS GH (Patient-Reported Outcomes Measurement Information System Global Health) Scale in Stroke: A Validation Study.

    Science.gov (United States)

    Katzan, Irene L; Lapin, Brittany

    2018-01-01

    The International Consortium for Health Outcomes Measurement recently included the 10-item PROMIS GH (Patient-Reported Outcomes Measurement Information System Global Health) scale as part of their recommended Standard Set of Stroke Outcome Measures. Before collection of PROMIS GH is broadly implemented, it is necessary to assess its performance in the stroke population. The objective of this study was to evaluate the psychometric properties of PROMIS GH in patients with ischemic stroke and intracerebral hemorrhage. PROMIS GH and 6 PROMIS domain scales measuring same/similar constructs were electronically collected on 1102 patients with ischemic and hemorrhagic strokes at various stages of recovery from their stroke who were seen in a cerebrovascular clinic from October 12, 2015, through June 2, 2017. Confirmatory factor analysis was performed to evaluate the adequacy of 2-factor structure of component scores. Test-retest reliability and convergent validity of PROMIS GH items and component scores were assessed. Discriminant validity and responsiveness were compared between PROMIS GH and PROMIS domain scales measuring the same or related constructs. Analyses were repeated stratified by stroke subtype and modified Rankin Scale score validity was good with significant correlations between all PROMIS GH items and PROMIS domain scales ( P 0.5) was demonstrated for 8 of the 10 PROMIS GH items. Reliability and validity remained consistent across stroke subtype and disability level (modified Rankin Scale, <2 versus ≥2). PROMIS GH exhibits acceptable performance in patients with stroke. Our findings support International Consortium for Health Outcomes Measurement recommendation to use PROMIS GH as part of the standard set of outcome measures in stroke. © 2017 American Heart Association, Inc.

  19. A study of low scores in Canadian children and adolescents on the Wechsler Intelligence Scale For Children, Fourth Edition (WISC-IV).

    Science.gov (United States)

    Brooks, Brian L

    2011-01-01

    Knowing the prevalence of low neurocognitive scores for the WISC-IV Canadian normative sample (WISC-IV(CDN)) is an important supplement for clinical interpretation of test performance. On the WISC-IV(CDN), it is uncommon for children and adolescents to have 4 or more subtest scores or 2 or more Index scores ≤ 9th percentile when all scores on the battery are considered simultaneously. As the level of the child's intelligence increases or the number of years of parental education increases, the prevalence of low scores decreases. These results are consistent with existing studies of the base rates of low scores in children and adolescents on pediatric cognitive batteries, including the WISC-IV American normative sample. Tables provided are ready for clinical use.

  20. Modelling of an air-cooled two-stage Rankine cycle for electricity production

    International Nuclear Information System (INIS)

    Liu, Bo

    2014-01-01

    This work considers a two stage Rankine cycle architecture slightly different from a standard Rankine cycle for electricity generation. Instead of expanding the steam to extremely low pressure, the vapor leaves the turbine at a higher pressure then having a much smaller specific volume. It is thus possible to greatly reduce the size of the steam turbine. The remaining energy is recovered by a bottoming cycle using a working fluid which has a much higher density than the water steam. Thus, the turbines and heat exchangers are more compact; the turbine exhaust velocity loss is lower. This configuration enables to largely reduce the global size of the steam water turbine and facilitate the use of a dry cooling system. The main advantage of such an air cooled two stage Rankine cycle is the possibility to choose the installation site of a large or medium power plant without the need of a large and constantly available water source; in addition, as compared to water cooled cycles, the risk regarding future operations is reduced (climate conditions may affect water availability or temperature, and imply changes in the water supply regulatory rules). The concept has been investigated by EDF R and D. A 22 MW prototype was developed in the 1970's using ammonia as the working fluid of the bottoming cycle for its high density and high latent heat. However, this fluid is toxic. In order to search more suitable working fluids for the two stage Rankine cycle application and to identify the optimal cycle configuration, we have established a working fluid selection methodology. Some potential candidates have been identified. We have evaluated the performances of the two stage Rankine cycles operating with different working fluids in both design and off design conditions. For the most acceptable working fluids, components of the cycle have been sized. The power plant concept can then be evaluated on a life cycle cost basis. (author)

  1. A hybrid Rankine cycle (HyRC) with ambient pressure combustion (APC)

    International Nuclear Information System (INIS)

    Wu, Lijun; Thimsen, David; Clements, Bruce; Zheng, Ligang; Pomalis, Richard

    2014-01-01

    The main losses in thermal power generation include heat in exhaust flue gas, heat rejected through steam condensation of low-pressure turbine, and exergy destruction in heat exchange process etc. To the extent that the heat losses are significantly greater in temperature than either air or water coolant resources, these losses also represent exergy losses which might be exploited to improve plant capacity and efficiency. This paper presents a hybrid Rankine cycle (HyRC) with an ambient pressure combustion (APC) boiler to address the recovery potential of these losses within the steam Rankine cycle (SRC). The APC–HyRC concept employs an organic Rankine cycle (ORC) to supplement SRC and to reduce cycle energy losses to the atmosphere since organic fluids are capable of lowering cycle condensation temperature when a very low temperature heat sink is available. The case studies based on a 399 MW SRC unit show that the APC–HyRC configurations have better thermodynamic performance than its base case SRC at a cycle condensation temperature of 30 °C and below. The best APC–HyRC configuration generates up to 14% more power than the baseline steam cycle which is a 5.45% increase in overall gross efficiency with a cycle condensation temperature at 4 °C. - Highlights: • A hybrid Rankine cycle with water and organic fluid is presented. • Heat losses in exhaust flue gas and exhaust steam are reduced. • Exergy losses in regeneration process are reduced. • Efficiency improvements are made to the conventional steam Rankine cycle. • Issues in design/construction of greenfield and repowering project are discussed

  2. Questionário específico para sintomas do joelho "Lysholm Knee Scoring Scale": tradução e validação para a língua portuguesa Specific questionnaire for knee symptoms - the "Lysholm Knee Scoring Scale": translation and validation into Portuguese

    Directory of Open Access Journals (Sweden)

    Maria Stella Peccin

    2006-01-01

    Full Text Available As doenças do joelho apresentam conseqüências variadas para a função e a qualidade de vida do indivíduo. Para traduzir, validar e verificar as propriedades de medida do questionário específico para sintomas do joelho "Lysholm Knee Scoring Scale" para a língua portuguesa, selecionamos, por conveniência, 50 pacientes (29 homens e 21 mulheres, média de idade 38,7 anos com lesão de joelho (lesão meniscal, lesão do ligamento cruzado anterior, condromalácia ou artrose. A reprodutibilidade e a concordância ordinal inter e intra-entrevistador foram excelentes (alfa = 0,9. A concordância nominal inter-entrevistadores foi boa (Kappa = 0,7 e intra-entrevistador, excelente (Kappa = 0,8. No processo de validação, correlacionamos o questionário Lysholm com a escala numérica da dor (r=-0,6; p=0,001 e com o índice de Lequesne (r= -0,8; p=0,001. As correlações entre o Lysholm e a avaliação global da saúde pelo paciente e pelo terapeuta apresentaram-se fracas e não significantes. As correlações entre o questionário Lysholm e o SF-36 foram significantes nos aspectos físicos (r = 0,4; p = 0,04, de dor (r = 0,5; p = 0,001 e de capacidade funcional (r = 0,7; p = 0,0001. Concluímos que a tradução e adaptação cultural do "Lysholm knee scoring scale" para o nosso idioma apresentou reprodutibilidade e validade em pacientes com lesão meniscal, lesão do ligamento cruzado anterior, condromalácia ou artrose do joelho.Knee diseases present variable consequences for an individual’s function and quality of life. For the purposes of translating, validating and checking the measurement properties of the specific questionnaire for knee symptoms - the "Lysholm Knee Scoring Scale" - into Portuguese, we selected, for convenience, 50 patients (29 males and 21 females, mean age = 38.7 years with knee injuries (meniscal injury, anterior cruciate ligament injury, chondromalacia or arthrosis. Reproducibility and ordinal consistency inter- and

  3. The large-scale blast score ratio (LS-BSR pipeline: a method to rapidly compare genetic content between bacterial genomes

    Directory of Open Access Journals (Sweden)

    Jason W. Sahl

    2014-04-01

    Full Text Available Background. As whole genome sequence data from bacterial isolates becomes cheaper to generate, computational methods are needed to correlate sequence data with biological observations. Here we present the large-scale BLAST score ratio (LS-BSR pipeline, which rapidly compares the genetic content of hundreds to thousands of bacterial genomes, and returns a matrix that describes the relatedness of all coding sequences (CDSs in all genomes surveyed. This matrix can be easily parsed in order to identify genetic relationships between bacterial genomes. Although pipelines have been published that group peptides by sequence similarity, no other software performs the rapid, large-scale, full-genome comparative analyses carried out by LS-BSR.Results. To demonstrate the utility of the method, the LS-BSR pipeline was tested on 96 Escherichia coli and Shigella genomes; the pipeline ran in 163 min using 16 processors, which is a greater than 7-fold speedup compared to using a single processor. The BSR values for each CDS, which indicate a relative level of relatedness, were then mapped to each genome on an independent core genome single nucleotide polymorphism (SNP based phylogeny. Comparisons were then used to identify clade specific CDS markers and validate the LS-BSR pipeline based on molecular markers that delineate between classical E. coli pathogenic variant (pathovar designations. Scalability tests demonstrated that the LS-BSR pipeline can process 1,000 E. coli genomes in 27–57 h, depending upon the alignment method, using 16 processors.Conclusions. LS-BSR is an open-source, parallel implementation of the BSR algorithm, enabling rapid comparison of the genetic content of large numbers of genomes. The results of the pipeline can be used to identify specific markers between user-defined phylogenetic groups, and to identify the loss and/or acquisition of genetic information between bacterial isolates. Taxa-specific genetic markers can then be translated

  4. Factors influencing pediatric Injury Severity Score and Glasgow Coma Scale in pediatric automobile crashes: results from the Crash Injury Research Engineering Network.

    Science.gov (United States)

    Ehrlich, Peter F; Brown, J Kristine; Sochor, Mark R; Wang, Stewart C; Eichelberger, Martin E

    2006-11-01

    Motor vehicle crashes account for more than 50% of pediatric injuries. Triage of pediatric patients to appropriate centers can be based on the crash/injury characteristics. Pediatric motor vehicle crash/injury characteristics can be determined from an in vitro laboratory using child crash dummies. However, to date, no detailed data with respect to outcomes and crash mechanism have been presented with a pediatric in vivo model. The Crash Injury Research Engineering Network is comprised of 10 level 1 trauma centers. Crashes were examined with regard to age, crash severity (DeltaV), crash direction, restraint use, and airbag deployment. Multiple logistic regression analysis was performed with Injury Severity Score (ISS) and Glasgow Coma Scale (GCS) as outcomes. Standard age groupings (0-4, 5-9, 10-14, and 15-18) were used. The database is biases toward a survivor population with few fatalities. Four hundred sixty-one motor vehicle crashes with 2500 injuries were analyzed (242 boys, 219 girls). Irrespective of age, DeltaV > 30 mph resulted in increased ISS and decreased GCS (eg, for 0-4 years, DeltaV 30: ISS = 19.5, GCS = 10.6; P 15) injuries than did backseat passengers (odds ratio, 1.7; 95% confidence interval, 0.7-3.4). A trend was noted for children younger than 12 years sitting in the front seat to have increased ISS and decreased GCS with airbag deployment but was limited by case number. A reproducible pattern of increased ISS and lower GCS characterized by high severity, lateral crashes in children was noted. Further analysis of the specific injuries as a function and the crash characteristic can help guide management and prevention strategies.

  5. 'Prostate Cancer Risk Calculator' mobile applications (Apps): a systematic review and scoring using the validated user version of the Mobile Application Rating Scale (uMARS).

    Science.gov (United States)

    Adam, Ahmed; Hellig, Julian C; Perera, Marlon; Bolton, Damien; Lawrentschuk, Nathan

    2018-04-01

    The use of mobile phone applications (Apps) has modernised the conventional practice of medicine. The diagnostic ability of the current Apps in prostate specific antigen monitoring, and its diagnostic ability within prostate cancer (PCa) risk calculators have not yet been appraised. We aimed to review, rate and assess the everyday functionality, and utility of all the currently available PCa risk calculator Apps. A systematic search on iTunes, Google Play Store, Blackberry World and Windows Apps Store, was performed on 23/11/2017, using the search term 'prostate cancer risk calculator'. After applying the exclusion criteria, each App was individually assessed and rated using pre-set criteria and grading was performed using the validated uMARS scale. In total, 83 Apps were retrieved. After applying our exclusion criteria, only 9 Apps were relevant, with 2 duplicated, and the remaining 7 were suitable for critical review. Data sizes ranged from 414 kb to 10.1 Mb. The cost of the Apps ranged from South African rand (ZAR) 0.00 to ZAR 29.99. The overall mean category uMARS scores ranged from 2.8/5 to 4.5/5. Apps such as Rotterdam Prostate Cancer Risk Calculator, Coral-Prostate Cancer Nomogram Calculator and CPC Risk Calculator, performed the best. The current PCa risk calculator mobile Apps available may be beneficial in counselling the concerned at risk patient. These Apps have potential to assist both the patient and the urologist alike. The PCa risk calculator App 'predictability' may be further enhanced by the incorporation of newly validated risk factors and predictors for PCa.

  6. The Basilar Artery on Computed Tomography Angiography Score for Acute Basilar Artery Occlusion Treated with Mechanical Thrombectomy.

    Science.gov (United States)

    Yang, Haihua; Ma, Ning; Liu, Lian; Gao, Feng; Mo, Dapeng; Miao, Zhongrong

    2018-06-01

    Recently, the Basilar Artery on Computed Tomography Angiography (BATMAN) score predicts clinical outcome of acute basilar artery occlusion (BAO), yet there is no extensive external validation. The purpose of this study was to validate the prognostic value of BATMAN scoring system for the prediction of clinical outcome in patients with acute BAO treated with endovascular mechanical thrombectomy by using cerebral digital subtraction angiography (DSA). We analyzed the clinical and angiographic data of consecutive patients with acute BAO from March 2012 to November 2016. The BATMAN scoring system was used to assess the collateral status and thrombus burden. Thrombolysis in Cerebral Infarction (TICI) score 2b-3 was defined as successful recanalization. Receiver operating characteristic (ROC) curve was used to determine the area under the curve (AUC) and the optimum cutoff value. Multivariate regression analysis was used to identify the predictor of clinical outcome. This study included 63 patients with acute BAO who underwent mechanical thrombectomy. Of these patients, 90.5% (57/63) achieved successful recanalization (TICI, 2b-3) and 34.9% (22/63) had a favorable outcome (modified Rankin Scale score 0-2). ROC analysis indicated that the AUC of the BATMAN score was .722 (95% confidence interval [CI], .594-.827), and the optimal cutoff value was 3 (sensitivity = 72.73, specificity = 63.41). In multivariate logistic regression analysis, the BATMAN score higher than 3 was associated with favorable outcome (odds ratio, 5.214; 95% CI, 1.47-18.483; P = .011). The BATMAN score on DSA seems to predict the functional outcome in patients of acute BAO treated with mechanical thrombectomy. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  7. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    Directory of Open Access Journals (Sweden)

    Jesper Graa Andreasen

    2017-04-01

    Full Text Available This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt % and low-sulfur (0.5 wt % fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane, toluene, n-pentane, i-pentane and c-pentane. The results of the comparison indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit turbines compared to the steam turbines. When the efficiency of the c-pentane turbine was allowed to be 10% points larger than the steam turbine efficiency, the organic Rankine cycle unit reaches higher net power outputs than the steam Rankine cycle unit at all engine loads for the low-sulfur fuel case. The net power production from the waste heat recovery units is generally higher for the low-sulfur fuel case. The steam Rankine cycle unit produces 18% more power at design compared to the high-sulfur fuel case, while the organic Rankine cycle unit using MM produces 33% more power.

  8. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Meroni, Andrea; Haglind, Fredrik

    2017-01-01

    %) fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane), toluene, n-pentane, i-pentane and c-pentane. The results of the comparison....... The net power production from the waste heat recovery units is generally higher for the low-sulfur fuel case. The steam Rankine cycle unit produces 18% more power at design compared to the high-sulfur fuel case, while the organic Rankine cycle unit using MM produces 33% more power....

  9. Quebec Back Pain Disability Scale, Low Back Outcome Score and revised Oswestry low back pain disability scale for patients with low back pain due to degenerative disc disease: evaluation of Polish versions.

    Science.gov (United States)

    Misterska, Ewa; Jankowski, Roman; Glowacki, Maciej

    2011-12-15

    Evaluation and comparison of translated and culturally adapted self-reported measurements. The aim of this prospective study was to cross-culturally adapt the Polish versions of Revised Oswestry Disability Index (RODI-PL), Quebec Back Pain Disability Scale (QDS-PL), and the Low Back Outcome Score (LBOS-PL). The application of instruments in English, which have undergone translation must be subjected to validation studies. Such studies are necessary above all for instruments that have been adapted to establish their value and usefulness in studies of patient populations where English is not the native language. The translation was carried out according to International Quality of Life Association (IQOLA) Project and consisted of the following stages: translation, synthesis of the translations, back translation, expert committee, and testing of the prefinal versions of questionnaires. Eighty-five consecutive patients with low back pain due to spinal disc herniation and degenerative changes completed the QDS-PL, RODI-PL, LBOS-PL, and a Visual Analogue Scale twice within 2-day intervals. Mean duration of LBP was 45.9 months SD 55.5. The evaluation of degenerative changes in the lumbar region was carried out according to the Modic scale. Twenty-nine patients were categorized at type I, 4 patients were registered as type II, and 52 patients were type III. Cronbach α values for the LBOS-PL equaled 0.77, for the RODI-PL 0.85, and 0.95 for the QDS-PL. Item-total correlation confirmed that all scales are internally consistent. Test-retest reliability was excellent for RODI-PL and QDS-PL, but poor for LBOS-PL (0.88, 0.93, and 0.34, respectively). All questionnaires were significantly intercorrelated. We identified the strongest correlation between QDS-PL and RODI-PL (0.823, P < 0.001). The statistically significant correlation was identified between the QDS-PL and Modic Classification (rS = 0.226 P = 0.038). QBPDS-PL and RODI-PL are reliable and valid. Furthermore

  10. A comparative analysis of rankine and absorption power cycles from exergoeconomic viewpoint

    International Nuclear Information System (INIS)

    Shokati, Naser; Ranjbar, Faramarz; Yari, Mortaza

    2014-01-01

    Highlights: • The Rankine and absorption power cycles are compared from exergoeconomic viewpoint. • The LiBr–H 2 O cycle has the highest unit cost of electricity produced by turbine. • The LiBr–H 2 O cycle has the lowest exergy destruction cost rate. • In LiBr–H 2 O cycle, the generator has the maximum value regarding (C-dot) D,k +(C-dot) L,k +(Z-dot) k . - Abstract: In this paper LiBr–H 2 O and NH 3 –H 2 O absorption power cycles and Rankine cycle which produce 1 MW electrical power in same conditions of heat sources are compared from exergoeconomic point of view. Exergoeconomic analysis is performed using the specific exergy costing (SPECO) method. The results show that among these cycles, although the LiBr–H 2 O cycle has the highest first law efficiency, but unit cost of electricity produced by turbine for LiBr–H 2 O cycle is more than that for Rankine cycle. This value is lowest for the NH 3 –H 2 O cycle. Moreover, the NH 3 –H 2 O cycle has the highest and the LiBr–H 2 O cycle has the lowest exergy destruction cost rate. The generator, the absorber and the boiler in all considered cycles have the maximum value of sum of cost rate associated with capital investment, operating and maintenance, exergy destruction and exergy losses. Therefore, these components should be taken into consideration from exergoeconomic viewpoint. In parametric study, it is observed that in the constant generator temperature, as the generator pressure increases, unit cost of power produced by turbine for LiBr–H 2 O and Rankine cycles decreases. This value for Rankine cycle is lower than for LiBr–H 2 O cycle whereas Rankine cycle efficiency is less than the efficiency of LiBr–H 2 O cycle. Also, in LiBr–H 2 O cycle, at constant temperature of the generator, the value of exergy destruction cost rate is minimized and exergoeconomic factor is maximized at particular values of generator pressure and the more absorber pressure results the minimum value of

  11. Scales

    Science.gov (United States)

    Scales are a visible peeling or flaking of outer skin layers. These layers are called the stratum ... Scales may be caused by dry skin, certain inflammatory skin conditions, or infections. Examples of disorders that ...

  12. Adverse drug reaction prediction using scores produced by large-scale drug-protein target docking on high-performance computing machines.

    Science.gov (United States)

    LaBute, Montiago X; Zhang, Xiaohua; Lenderman, Jason; Bennion, Brian J; Wong, Sergio E; Lightstone, Felice C

    2014-01-01

    Late-stage or post-market identification of adverse drug reactions (ADRs) is a significant public health issue and a source of major economic liability for drug development. Thus, reliable in silico screening of drug candidates for possible ADRs would be advantageous. In this work, we introduce a computational approach that predicts ADRs by combining the results of molecular docking and leverages known ADR information from DrugBank and SIDER. We employed a recently parallelized version of AutoDock Vina (VinaLC) to dock 906 small molecule drugs to a virtual panel of 409 DrugBank protein targets. L1-regularized logistic regression models were trained on the resulting docking scores of a 560 compound subset from the initial 906 compounds to predict 85 side effects, grouped into 10 ADR phenotype groups. Only 21% (87 out of 409) of the drug-protein binding features involve known targets of the drug subset, providing a significant probe of off-target effects. As a control, associations of this drug subset with the 555 annotated targets of these compounds, as reported in DrugBank, were used as features to train a separate group of models. The Vina off-target models and the DrugBank on-target models yielded comparable median area-under-the-receiver-operating-characteristic-curves (AUCs) during 10-fold cross-validation (0.60-0.69 and 0.61-0.74, respectively). Evidence was found in the PubMed literature to support several putative ADR-protein associations identified by our analysis. Among them, several associations between neoplasm-related ADRs and known tumor suppressor and tumor invasiveness marker proteins were found. A dual role for interstitial collagenase in both neoplasms and aneurysm formation was also identified. These associations all involve off-target proteins and could not have been found using available drug/on-target interaction data. This study illustrates a path forward to comprehensive ADR virtual screening that can potentially scale with increasing number

  13. Adverse drug reaction prediction using scores produced by large-scale drug-protein target docking on high-performance computing machines.

    Directory of Open Access Journals (Sweden)

    Montiago X LaBute

    Full Text Available Late-stage or post-market identification of adverse drug reactions (ADRs is a significant public health issue and a source of major economic liability for drug development. Thus, reliable in silico screening of drug candidates for possible ADRs would be advantageous. In this work, we introduce a computational approach that predicts ADRs by combining the results of molecular docking and leverages known ADR information from DrugBank and SIDER. We employed a recently parallelized version of AutoDock Vina (VinaLC to dock 906 small molecule drugs to a virtual panel of 409 DrugBank protein targets. L1-regularized logistic regression models were trained on the resulting docking scores of a 560 compound subset from the initial 906 compounds to predict 85 side effects, grouped into 10 ADR phenotype groups. Only 21% (87 out of 409 of the drug-protein binding features involve known targets of the drug subset, providing a significant probe of off-target effects. As a control, associations of this drug subset with the 555 annotated targets of these compounds, as reported in DrugBank, were used as features to train a separate group of models. The Vina off-target models and the DrugBank on-target models yielded comparable median area-under-the-receiver-operating-characteristic-curves (AUCs during 10-fold cross-validation (0.60-0.69 and 0.61-0.74, respectively. Evidence was found in the PubMed literature to support several putative ADR-protein associations identified by our analysis. Among them, several associations between neoplasm-related ADRs and known tumor suppressor and tumor invasiveness marker proteins were found. A dual role for interstitial collagenase in both neoplasms and aneurysm formation was also identified. These associations all involve off-target proteins and could not have been found using available drug/on-target interaction data. This study illustrates a path forward to comprehensive ADR virtual screening that can potentially scale with

  14. [Hemostasiological, lipidemic, and hemodynamic indicators associated with the risk of cardiovascular death in high- and very high-risk patients according to the SCORE scale].

    Science.gov (United States)

    Kachkovskiĭ, M A; Simerzin, V V; Rybanenko, O A; Kirichenko, N A

    2014-01-01

    To identify lipidemic, hemostasiological, and hemodynamic indicators associated with the risk of cardiovascular death in high- and very high-risk patients. One hundred and forty-eight patients whose mean age was 50.8 +/- 4.4 years were examined. All the patients were divided into high (1 group) and very high (2 group) cardiovascular death risk groups according to the SCORE scale. Lipid metabolism, hemostatic system parameters (fibrinogen, time of ADP-induced platelet aggregation initiation, D-dimer), endothelial dysfunction markers (von Willebrand factor), and echocardiographic findings were studied. Multivariate regression analysis showed that the odds ratio for a cardiovascular death risk was 1.8 (95% confidence interval (CI), 1.1 to 4.2; p = 0.04) in patients with a D-dimer level of greater than 1 mg/ml, 0.77 (95% CI, 0.6 to 0.97; p = 0.03) in those with an ADP-induced platelet aggregation initiation time of 13.5 sec, 1.04 (95% CI, 1.01 to 1.07; p = 0.02) in those with an end-diastolic volume of more than 123 ml, 1.1 (95% CI, 1.04 to 1.2; p = 0.003) in those with an end-diastolic dimension of more than 51 mm, 1.5 (95% CI, 1.1 to 2.0; p = 0.009) in those with a ventricular septal thickness of more than 11.5 mm, and 2.1 (95% CI, 1.03 to 3.2; p = 0.0032) in those with avon Willebrand factor level of more than 140%. The high levels of von Willebrand factor, D-dimer, ADP-induced platelet aggregation, triglycerides, end-diastolic volume, end-diastolic dimension, and ventricular septal thickness are independent predictors of cardiovascular death in very high-risk patients. These indicators bear out a close relationship between lipid metabolic and hemostatic disturbances and between endothelial dysfunction and intracardiac hemodynamic worsening in these patients.

  15. Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

    Science.gov (United States)

    Douvartzides, S.; Karmalis, I.

    2016-11-01

    Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

  16. Investigations on the application of zeotropic fluid mixtures in the organic rankine cycle for the geothermal power generation; Untersuchung zum Einsatz von zeotropen Fluidgemischen im Organic Rankine Cycle fuer die geothermische Stromerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Heberle, Florian

    2013-04-01

    The organic rankine cycle is a thermodynamic cycle process which uses an organic fluid working fluid instead of water in comparison to the commercial rankine process. The organic rankine cycle facilitates sufficiently high pressures at moderate temperatures. The organic rankine cycle significantly expands the technically possible and economically feasible ranges of application of such heat and power processes. The geothermal power is a very attractive field of application. Thermal water with a temperature of nearly 100 Celsius can be used for the power generation by means of the organic rankine cycle. Especially zeotropic mixtures are interesting as a working fluid. This is due to a non-isothermal phase change to a temperature glide which adapts very well to the temperature progress of the heat source. The author of the book under consideration reports on the application of different mixtures in the organic rankine cycle. The evaluation is based on a thermodynamic analysis and considers also toxicological, ecologic, technical as well as economic aspects.

  17. Prestroke CHA2DS2-VASc Score and Severity of Acute Stroke in Patients with Atrial Fibrillation: Findings from RAF Study.

    Science.gov (United States)

    Acciarresi, Monica; Paciaroni, Maurizio; Agnelli, Giancarlo; Falocci, Nicola; Caso, Valeria; Becattini, Cecilia; Marcheselli, Simona; Rueckert, Christina; Pezzini, Alessandro; Morotti, Andrea; Costa, Paolo; Padovani, Alessandro; Csiba, Laszló; Szabó, Lilla; Sohn, Sung-Il; Tassinari, Tiziana; Abdul-Rahim, Azmil H; Michel, Patrik; Cordier, Maria; Vanacker, Peter; Remillard, Suzette; Alberti, Andrea; Venti, Michele; D'Amore, Cataldo; Scoditti, Umberto; Denti, Licia; Orlandi, Giovanni; Chiti, Alberto; Gialdini, Gino; Bovi, Paolo; Carletti, Monica; Rigatelli, Alberto; Putaala, Jukka; Tatlisumak, Turgut; Masotti, Luca; Lorenzini, Gianni; Tassi, Rossana; Guideri, Francesca; Martini, Giuseppe; Tsivgoulis, Georgios; Vadikolias, Kostantinos; Liantinioti, Chrissoula; Corea, Francesco; Del Sette, Massimo; Ageno, Walter; De Lodovici, Maria Luisa; Bono, Giorgio; Baldi, Antonio; D'Anna, Sebastiano; Sacco, Simona; Carolei, Antonio; Tiseo, Cindy; Imberti, Davide; Zabzuni, Dorjan; Doronin, Boris; Volodina, Vera; Consoli, Domenico; Galati, Franco; Pieroni, Alessio; Toni, Danilo; Monaco, Serena; Baronello, Mario Maimone; Barlinn, Kristian; Pallesen, Lars-Peder; Kepplinger, Jessica; Bodechtel, Ulf; Gerber, Johannes; Deleu, Dirk; Melikyan, Gayane; Ibrahim, Faisal; Akhtar, Naveed; Mosconi, Maria Giulia; Lees, Kennedy R

    2017-06-01

    The aim of this study was to investigate for a possible association between both prestroke CHA 2 DS 2 -VASc score and the severity of stroke at presentation, as well as disability and mortality at 90 days, in patients with acute stroke and atrial fibrillation (AF). This prospective study enrolled consecutive patients with acute ischemic stroke, AF, and assessment of prestroke CHA 2 DS 2 -VASc score. Severity of stroke was assessed on admission using the National Institutes of Health Stroke Scale (NIHSS) score (severe stroke: NIHSS ≥10). Disability and mortality at 90 days were assessed by the modified Rankin Scale (mRS <3 or ≥3). Multiple logistic regression was used to correlate prestroke CHA 2 DS 2 -VASc and severity of stroke, as well as disability and mortality at 90 days. Of the 1020 patients included in the analysis, 606 patients had an admission NIHSS score lower and 414 patients higher than 10. At 90 days, 510 patients had mRS ≥3. A linear correlation was found between the prestroke CHA 2 DS 2 -VASc score and severity of stroke (P = .001). On multivariate analysis, CHA 2 DS 2 -VASc score correlated with severity of stroke (P = .041) and adverse functional outcome (mRS ≥3) (P = .001). A logistic regression with the receiver operating characteristic graph procedure (C-statistics) evidenced an area under the curve of .60 (P = .0001) for severe stroke. Furthermore, a correlation was found between prestroke CHA 2 DS 2 -VASc score and lesion size. In patients with AF, in addition to the risk of stroke, a high CHA 2 DS 2 -VASc score was independently associated with both stroke severity at onset and disability and mortality at 90 days. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  18. Comparative thermodynamic performance of some Rankine/Brayton cycle configurations for a low-temperature energy application

    Science.gov (United States)

    Lansing, F. L.

    1977-01-01

    Various configurations combining solar-Rankine and fuel-Brayton cycles were analyzed in order to find the arrangement which has the highest thermal efficiency and the smallest fuel share. A numerical example is given to evaluate both the thermodynamic performance and the economic feasibility of each configuration. The solar-assisted regenerative Rankine cycle was found to be leading the candidates from both points of energy utilization and fuel conservation.

  19. Studi Variasi Flowrate Refrigerant pada Sistem Organic Rankine Cycle dengan Fluida Kerja R-123

    Directory of Open Access Journals (Sweden)

    Aria Halim Pamungkas

    2013-09-01

    Full Text Available Saat ini kelangkaan sumber energi fosil telah menjadi isu utama di seluruh dunia. Hal tersebut memberikan dampak yang signifikan di setiap aspek kehidupan dan salah satunya adalah di bidang pembangkit listrik. Salah satu sistem pembangkit listrik yang tidak menggunakan energi fosil adalah Organic rankine cycle (ORC. Pada penelitian ini dilakukan dengan metode eksperimental pada suatu sistem Organic rankine cycle yang telah dibangun. Penelitian ini yang divariasikan adalah flowrate dari fluida kerja dalam hal ini R-123. Variasi flowrate yang digunakan yaitu 3-1 GPM (Galon per menit dengan penurunan 0,5 GPM setiap pengambilan data. Hasil yang didapatkan dari penelitian ini berupa grafik–grafik daya pada turbin, kondensor, pompa dan evaporator, efisiensi siklus dan back work ratio  fungsi flowrate fluida kerja. Efisiensi siklus tertinggi adalah 5,86% yang terjadi pada flowrate 3 GPM dan efisiensi siklus terendah adalah 4,32% yang terjadi pada flowrate 1 GPM.

  20. A review of the use of organic Rankine cycle power systems for maritime applications

    DEFF Research Database (Denmark)

    Mondejar, M. E.; Andreasen, J. G.; Pierobon, L.

    2018-01-01

    Diesel engines are by far the most common means of propulsion aboard ships. It is estimated that around half of their fuel energy consumption is dissipated as low-grade heat. The organic Rankine cycle technology is a well-established solution for the energy conversion of thermal power from biomass...... combustion, geothermal reservoirs, and waste heat from industrial processes. However, its economic feasibility has not yet been demonstrated for marine applications. This paper aims at evaluating the potential of using organic Rankine cycle systems for waste heat recovery aboard ships. The suitable vessels...... and engine heat sources are identified by estimating the total recoverable energy. Different cycle architectures, working fluids, components, and control strategies are analyzed. The economic feasibility and integration on board are also evaluated. A number of research and development areas are identified...

  1. Study of toluene stability for an Organic Rankine Cycle (ORC) space-based power system

    Science.gov (United States)

    Havens, Vance; Ragaller, Dana

    1988-01-01

    The design, fabrication, assembly, and endurance operation of a dynamic test loop, built to evaluate the thermal stability of a proposed Organic Rankine Cycle (ORC) working fluid, is discussed. The test fluid, toluene, was circulated through a heater, simulated turbine, regenerator, condenser and pump to duplicate an actual ORC system. The maximum nominal fluid temperature, 750 F, was at the turbine simulator inlet. Samples of noncondensible gases and liquid toluene were taken periodically during the test. The samples were analyzed to identify the degradation products formed and the quantity of these products. From these data it was possible to determine the degradation rate of the working fluid and the generation rate of noncondensible gases. A further goal of this work was to relate the degradation observed in the dynamic operating loop to degradation obtained in isothermal capsule tests. This relationship was the basis for estimating the power loop degradation in the Space Station Organic Rankine Cycle system.

  2. Modeling and analysis of scroll compressor conversion into expander for Rankine cycles

    Energy Technology Data Exchange (ETDEWEB)

    Oralli, E.; Dincer, I.; Zamfirescu, C. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (Canada)], E-mail: Emre.Oralli@uoit.ca, email: Ibrahim.Dincer@uoit.ca, email: Calin.Zamfirescu@uoit.ca

    2011-07-01

    With the current push towards the use of sustainable energies, low power heat generation systems are shifting towards sustainable heat sources such as geothermal, solar, industrial waste and cogeneration energy. The aim of this paper is to investigate the use of a scroll expander for power generation using the Rankine cycle. A parametric study was carried out on a refrigeration scroll compressor to determine the impact of geometry, working fluid, and operating conditions on the efficiency of the Rankine heat engine. In addition modifications were made to the expander to optimize its operation. Results showed that organic fluids should be used at saturated conditions, that decreasing the temperature of the condenser leads to an increased thermal efficiency of ORC and that the designed radius is an optimum value. This study highlighted the impacts of geometric and thermodynamic parameters on scroll expanders.

  3. Performance Estimation of Organic Rankine Cycle by Using Soft Computing Technics

    Directory of Open Access Journals (Sweden)

    Tuğba Kovacı

    2017-10-01

    Full Text Available In this study, the thermal efficiency values of Organic Rankine cycle system were estimated depending on the condenser temperature and the evaporator temperatures values by adaptive network fuzzy interference system (ANFIS and artificial neural networks system (ANN. Organic Rankine cycle (ORC fluids of R365-mfc and SES32 were chosen to evaluate as the system fluid. The performance values of ANN and ANFIS models are compared with actual values. The R2 values are determined between 0.97 and 0.99 for SES36 and R365-mfc, and this is satisfactory. Although it was observed that both ANN and ANFIS models obtained a good statistical prediction performance through coefficient of determination variance, the accuracies of ANN predictions were usually imperceptible better than those of ANFIS predictions.

  4. Carga de trabajo en tres grupos de pacientes de UCI Española según el Nursing Activities Score Carga de trabalho em três grupos de pacientes em uma UTI espanhola segundo Nursing Activites Score Assessment of nursing workload in three groups of patients in a Spanish ICU using the Nursing Activities Score Scale

    Directory of Open Access Journals (Sweden)

    Francisco Javier Carmona-Monge

    2013-04-01

    diferentes grupos de pacientes que passam com mais frequência pelas unidades de cuidados intensivos.The purpose of this study was to assess the nursing workload at admission to and discharge from intensive care of three groups of patients (i.e., acute coronary syndrome, acute respiratory failure, and sepsis. A prospective, descriptive study was performed over a 27-month period and included 563 patients. The workload was assessed using the Nursing Activities Score scale. Significant differences in the workload were determined on the days of admission and discharge: the workload was higher in both cases for patients with acute respiratory failure and sepsis compared with patients diagnosed with acute coronary syndrome. This difference was maintained over the first seven days of their hospital stay. From day 8 on, the difference disappeared, and a workload balance was achieved in the three groups. Good staffing requires adequate tools for measuring care needs and understanding the workload required in the groups of patients who are most frequently admitted to intensive care.

  5. Instability of a two-step Rankine vortex in a reduced gravity QG model

    Energy Technology Data Exchange (ETDEWEB)

    Perrot, Xavier [Laboratoire de Météorologie Dynamique, Ecole Normale Supérieure, 24 rue Lhomond, F-75005 Paris (France); Carton, Xavier, E-mail: xperrot@lmd.ens.fr, E-mail: xcarton@univ-brest.fr [Laboratoire de Physique des Océans, Université de Bretagne Occidentale, 6 avenue Le Gorgeu, F-29200 Brest (France)

    2014-06-01

    We investigate the stability of a steplike Rankine vortex in a one-active-layer, reduced gravity, quasi-geostrophic model. After calculating the linear stability with a normal mode analysis, the singular modes are determined as a function of the vortex shape to investigate short-time stability. Finally we determine the position of the critical layer and show its influence when it lies inside the vortex. (papers)

  6. System and method for regulating EGR cooling using a rankine cycle

    Science.gov (United States)

    Ernst, Timothy C.; Morris, Dave

    2015-12-22

    This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

  7. Parametric Adjustments to the Rankine Vortex Wind Model for Gulf of Mexico Hurricanes

    Science.gov (United States)

    2012-11-01

    2012 4. TITLE AND SUBTITLE Parametric Adjustments to the Rankine Vortex Wind Model for Gulf of Mexico Hurricanes 5a. CONTRACT NUMBER 5b. GRANT ...may be used to construct spatially varying wind fields for the GOM region (e.g., Thompson and Cardone [12]), but this requires using a complicated...Storm Damage Reduc- tion, and Dredging Operations and Environmental Research (DOER). The USACE Headquarters granted permission to publish this paper

  8. Energy and exergy analysis of integrated system of ammonia–water Kalina–Rankine cycle

    International Nuclear Information System (INIS)

    Chen, Yaping; Guo, Zhanwei; Wu, Jiafeng; Zhang, Zhi; Hua, Junye

    2015-01-01

    The integrated system of AWKRC (ammonia–water Kalina–Rankine cycle) is a novel cycle operated on KC (Kalina cycle) for power generation in non-heating seasons and on AWRC (ammonia–water Rankine cycle) for cogeneration of power and heating water in winter. The influences of inlet temperatures of both heat resource and cooling water on system efficiencies were analyzed based on the first law and the second law of thermodynamics. The calculation is based on following conditions that the heat resource temperature keeps 300 °C, the cooling water temperature for the KC or AWRC is respectively 25 °C or 15 °C; and the temperatures of heating water and backwater are respectively 90 °C and 40 °C. The results show that the evaluation indexes of the power recovery efficiency and the exergy efficiency of KC were respectively 18.2% and 41.9%, while the composite power recovery efficiency and the composite exergy efficiency of AWRC are respectively 21.1% and 43.0% accounting both power and equivalent power of cogenerated heating capacity, including 54.5% heating recovery ratio or 12.4% heating water exergy efficiency. The inventory flow diagrams of both energy and exergy gains and losses of the components operating on KC or AWRC are also demonstrated. - Highlights: • An integrated system of AWKRC (ammonia–water Kalina–Rankine cycle) is investigated. • NH_3–H_2O Rankine cycle is operated for cogenerating power and heating-water in winter. • Heating water with 90 °C and capacity of 54% total reclaimed heat load is cogenerated. • Kalina cycle is operated for power generation in other seasons with high efficiency. • Energy and exergy analysis draw similar results in optimizing the system parameters.

  9. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    OpenAIRE

    Suresh Baral; Kyung Chun Kim

    2015-01-01

    The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC) water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal ef...

  10. Thermo- economical consideration of Regenerative organic Rankine cycle coupling with the absorption chiller systems incorporated in the trigeneration system

    International Nuclear Information System (INIS)

    Anvari, Simin; Taghavifar, Hadi; Parvishi, Alireza

    2017-01-01

    Highlights: • A new trigeneration cycle was studied from a new viewpoint of exergoeconomic and thermodynamic. • Organic Rankine and refrigeration cycles are used for recovery waste heat of cogeneration system. • Application of trigeneration cycles is advantageous in economical and thermodynamic aspects. - Abstract: In this paper, a combined cooling, heating and power cycle is proposed consisting of three sections of gas turbine and heat recovery steam generator cycle, Regenerative organic Rankine cycle, and absorption refrigeration cycle. This trigeneration cycle is subjected to a thorough thermodynamic and exergoeconomic analysis. The principal goal followed in the investigation is to address the thermodynamic and exergoeconomic of a trigeneration cycle from a new prospective such that the economic and thermodynamic viability of incorporating Regenerative organic Rankine cycle, and absorption refrigeration cycle to the gas turbine and heat recovery steam generator cycle is being investigated. Thus, the cost-effectiveness of the introduced method can be studied and further examined. The results indicate that adding Regenerative organic Rankine cycle to gas turbine and heat recovery steam generator cycle leads to 2.5% increase and the addition of absorption refrigeration cycle to the gas turbine and heat recovery steam generator/ Regenerative Organic Rankine cycle would cause 0.75% increase in the exergetic efficiency of the entire cycle. Furthermore, from total investment cost of the trigeneration cycle, only 5.5% and 0.45% results from Regenerative organic Rankine cycle and absorption refrigeration cycles, respectively.

  11. Advanced Rotator Cuff Tear Score (ARoCuS): a multi-scaled tool for the classification and description of rotator cuff tears.

    Science.gov (United States)

    Walter, S G; Stadler, T; Thomas, T S; Thomas, W

    2018-03-02

    To introduce a (semi-)quantitative surgical score for the classification of rotator cuff tears. A total of 146 consecutive patients underwent rotator cuff repair and were assessed using the previously defined Advanced Rotator Cuff Tear Score (ARoCuS) criteria: muscle tendon, size, tissue quality, pattern as well as mobilization of the tear. The data set was split into a training (125 patients) and a testing set (21 patients). The training data set fitted a nonlinear predictive model of the tear score based on the ARoCuS criteria, while the testing data served as control. Based on the scoring results, rotator cuff tears were assigned to one of four categories (ΔV I-IV) and received a stage-adapted treatment. For statistical analysis, mean values ± standard deviation, interclass correlation coefficients (ICC) and kappa values were calculated. Overall, 32 patients were classified as ΔV I, 68 as ΔV II and 37 as ΔV III. Nine patients showed ΔV IV tears. Patients of all ΔV groups improved significantly their Constant scores (p tears in a standardized and reproducible manner.

  12. Thermodynamic analysis of high-temperature regenerative organic Rankine cycles using siloxanes as working fluids

    International Nuclear Information System (INIS)

    Fernandez, F.J.; Prieto, M.M.; Suarez, I.

    2011-01-01

    A recent novel adjustment of the Span-Wagner equation of state for siloxanes, used as working fluids in high-temperature organic Rankine cycles, is applied in a mathematical model to solve cycles under several working conditions. The proposed scheme includes a thermo-oil intermediate heat circuit between the heat source and the organic Rankine cycle. Linear and cyclic siloxanes are assayed in saturated, superheated and supercritical cycles. The cycle includes an internal heat exchanger (regenerative cycle), although a non-regenerative scheme is also solved. In the first part of the study, a current of combustion gases cooled to close to their dew point temperature is taken as the reference heat source. In the second part, the outlet temperature of the heat source is varied over a wide range, determining appropriate fluids and schemes for each thermal level. Simple linear (MM, MDM) siloxanes in saturated regenerative schemes show good efficiencies and ensure thermal stability of the working fluid. -- Highlights: → Organic Rankine cycles with polymethylsiloxanes as working fluids were modelled. → The cycle scheme is regenerative and includes an intermediate heat transfer fluid. → The fluid properties were calculated by means of the Span-Wagner equation of state. → Vapour conditions to the expander and source thermal level were analysed. → Siloxanes MM, MDM and D 4 under saturated conditions were the best options.

  13. Design of a Rankine cycle operating with a passive turbine multi fluid

    Energy Technology Data Exchange (ETDEWEB)

    Placco, Guilherme M., E-mail: guilhermeplacco@gmail.com [Instituto Tecnológico de Aeronáutica (ITA), São José dos Campos, SP (Brazil); Guimarães, Lamartine N.F., E-mail: guimarae@ieav.cta.br [Instituto de Estudo Avançados (CTA/IEAV), São José dos Campos, SP, (Brazil); Santos, Gabriela S. B., E-mail: siqueira.gsb@gmail.com [Universidade Paulista (UNIP), São José dos Campos, SP (Brazil)

    2017-07-01

    The Institute of Advanced Studies - IEAv, has been conducting a project called TERRA - 'Fast Advanced Reactors Technology', which aims to study the effects on the working of a Rankine cycle operating with a Multi Fluid Passive Turbine - TPMF. This turbine has the main characteristic operate bladeless using discs arranged in parallel along a rotating axis. After a thorough literature search, we have not found a previous operating Rankine cycle with this kind of turbine. Thus, the work presented here, began its development with few guidelines to follow. It will be presented, of a sucint way, of the design of the parts that makes up a Rankine cycle; the boundary conditions of the cycle; Data acquisition system; the development schedule; assembly of the components; some associated costs and project management. Experimental results thermal conduction through the cycle; the results of net power generated by the turbine and a comparison between thermal energy to mechanical energy in the turbine (efficiency curve). (author)

  14. Design of a Rankine cycle operating with a passive turbine multi fluid

    International Nuclear Information System (INIS)

    Placco, Guilherme M.; Guimarães, Lamartine N.F.; Santos, Gabriela S. B.

    2017-01-01

    The Institute of Advanced Studies - IEAv, has been conducting a project called TERRA - 'Fast Advanced Reactors Technology', which aims to study the effects on the working of a Rankine cycle operating with a Multi Fluid Passive Turbine - TPMF. This turbine has the main characteristic operate bladeless using discs arranged in parallel along a rotating axis. After a thorough literature search, we have not found a previous operating Rankine cycle with this kind of turbine. Thus, the work presented here, began its development with few guidelines to follow. It will be presented, of a sucint way, of the design of the parts that makes up a Rankine cycle; the boundary conditions of the cycle; Data acquisition system; the development schedule; assembly of the components; some associated costs and project management. Experimental results thermal conduction through the cycle; the results of net power generated by the turbine and a comparison between thermal energy to mechanical energy in the turbine (efficiency curve). (author)

  15. On the Rankin-Selberg method for higher genus string amplitudes

    CERN Document Server

    Florakis, Ioannis

    2017-01-01

    Closed string amplitudes at genus $h\\leq 3$ are given by integrals of Siegel modular functions on a fundamental domain of the Siegel upper half-plane. When the integrand is of rapid decay near the cusps, the integral can be computed by the Rankin-Selberg method, which consists of inserting an Eisenstein series $E_h(s)$ in the integrand, computing the integral by the orbit method, and finally extracting the residue at a suitable value of $s$. String amplitudes, however, typically involve integrands with polynomial or even exponential growth at the cusps, and a renormalization scheme is required to treat infrared divergences. Generalizing Zagier's extension of the Rankin-Selberg method at genus one, we develop the Rankin-Selberg method for Siegel modular functions of degree 2 and 3 with polynomial growth near the cusps. In particular, we show that the renormalized modular integral of the Siegel-Narain partition function of an even self-dual lattice of signature $(d,d)$ is proportional to a residue of the Langla...

  16. Performance analysis of double organic Rankine cycle for discontinuous low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Wang Dongxiang; Ling Xiang; Peng Hao

    2012-01-01

    This research proposes a double organic Rankine cycle for discontinuous waste heat recovery. The optimal operation conditions of several working fluids have been calculated by a procedure employing MATLAB and REFPROP. The influence of outlet temperature of heat source on the net power output, thermal efficiency, power consumption, mass flow rate, expander outlet temperature, cycle irreversibility and exergy efficiency at a given pinch point temperature difference (PPTD) has been analyzed. Pinch point analysis has also been employed to obtain a thermodynamic understanding of the ORC performance. Of all the working fluids investigated, some performances between each working fluid are rather similar. For a fixed low temperature heat source, the optimal operation condition should be mainly determined by the heat carrier of the heat source, and working fluids have limited influence. Lower outlet temperature of heat source does not always mean more efficient energy use. Acetone exhibits the least exergy destruction, while R245fa possesses the maximal exergy efficiency at a fixed PPTD. Wet fluids exhibit lower thermal efficiency than the others with the increasing of PPTD at a fixed outlet temperature of heat source. Dry and isentropic fluids offer attractive performance. - Highlights: ► We propose a double organic Rankine cycle for discontinuous waste heat recovery. ► Performance of organic Rankine cycle (ORC) is analyzed by pinch point analysis. ► The heat carrier of the heat source determines ORC optimal operation condition. ► Design of ORC heat exchangers prefers lower pinch point temperature difference.

  17. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    Directory of Open Access Journals (Sweden)

    Bing Hu

    2014-01-01

    Full Text Available To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m−2 and 7.61 kg m−2 day−1 at the generation temperature of 140°C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.

  18. Technical and economic study of Stirling and Rankine cycle bottoming systems for heavy truck diesel engines

    Science.gov (United States)

    Kubo, I.

    1987-01-01

    Bottoming cycle concepts for heavy duty transport engine applications were studied. In particular, the following tasks were performed: (1) conceptual design and cost data development for Stirling systems; (2) life-cycle cost evaluation of three bottoming systems - organic Rankine, steam Rankine, and Stirling cycles; and (3) assessment of future directions in waste heat utilization research. Variables considered for the second task were initial capital investments, fuel savings, depreciation tax benefits, salvage values, and service/maintenance costs. The study shows that none of the three bottoming systems studied are even marginally attractive. Manufacturing costs have to be reduced by at least 65%. As a new approach, an integrated Rankine/Diesel system was proposed. It utilizes one of the diesel cylinders as an expander and capitalizes on the in-cylinder heat energy. The concept eliminates the need for the power transmission device and a sophisticated control system, and reduces the size of the exhaust evaporator. Results of an economic evaluation indicate that the system has the potential to become an attractive package for end users.

  19. Mapping health assessment questionnaire disability index (HAQ-DI) score, pain visual analog scale (VAS), and disease activity score in 28 joints (DAS28) onto the EuroQol-5D (EQ-5D) utility score with the KORean Observational study Network for Arthritis (KORONA) registry data.

    Science.gov (United States)

    Kim, Hye-Lin; Kim, Dam; Jang, Eun Jin; Lee, Min-Young; Song, Hyun Jin; Park, Sun-Young; Cho, Soo-Kyung; Sung, Yoon-Kyoung; Choi, Chan-Bum; Won, Soyoung; Bang, So-Young; Cha, Hoon-Suk; Choe, Jung-Yoon; Chung, Won Tae; Hong, Seung-Jae; Jun, Jae-Bum; Kim, Jinseok; Kim, Seong-Kyu; Kim, Tae-Hwan; Kim, Tae-Jong; Koh, Eunmi; Lee, Hwajeong; Lee, Hye-Soon; Lee, Jisoo; Lee, Shin-Seok; Lee, Sung Won; Park, Sung-Hoon; Shim, Seung-Cheol; Yoo, Dae-Hyun; Yoon, Bo Young; Bae, Sang-Cheol; Lee, Eui-Kyung

    2016-04-01

    The aim of this study was to estimate the mapping model for EuroQol-5D (EQ-5D) utility values using the health assessment questionnaire disability index (HAQ-DI), pain visual analog scale (VAS), and disease activity score in 28 joints (DAS28) in a large, nationwide cohort of rheumatoid arthritis (RA) patients in Korea. The KORean Observational study Network for Arthritis (KORONA) registry data on 3557 patients with RA were used. Data were randomly divided into a modeling set (80 % of the data) and a validation set (20 % of the data). The ordinary least squares (OLS), Tobit, and two-part model methods were employed to construct a model to map to the EQ-5D index. Using a combination of HAQ-DI, pain VAS, and DAS28, four model versions were examined. To evaluate the predictive accuracy of the models, the root-mean-square error (RMSE) and mean absolute error (MAE) were calculated using the validation dataset. A model that included HAQ-DI, pain VAS, and DAS28 produced the highest adjusted R (2) as well as the lowest Akaike information criterion, RMSE, and MAE, regardless of the statistical methods used in modeling set. The mapping equation of the OLS method is given as EQ-5D = 0.95-0.21 × HAQ-DI-0.24 × pain VAS/100-0.01 × DAS28 (adjusted R (2) = 57.6 %, RMSE = 0.1654 and MAE = 0.1222). Also in the validation set, the RMSE and MAE were shown to be the smallest. The model with HAQ-DI, pain VAS, and DAS28 showed the best performance, and this mapping model enabled the estimation of an EQ-5D value for RA patients in whom utility values have not been measured.

  20. A comparison of global rating scale and checklist scores in the validation of an evaluation tool to assess performance in the resuscitation of critically ill patients during simulated emergencies (abbreviated as "CRM simulator study IB").

    Science.gov (United States)

    Kim, John; Neilipovitz, David; Cardinal, Pierre; Chiu, Michelle

    2009-01-01

    Crisis resource management (CRM) skills are a set of nonmedical skills required to manage medical emergencies. There is currently no gold standard for evaluation of CRM performance. A prior study examined the use of a global rating scale (GRS) to evaluate CRM performance. This current study compared the use of a GRS and a checklist as formal rating instruments to evaluate CRM performance during simulated emergencies. First-year and third-year residents participated in two simulator scenarios each. Three raters then evaluated resident performance in CRM using edited video recordings using both a GRS and a checklist. The Ottawa GRS provides a seven-point anchored ordinal scale for performance in five categories of CRM, and an overall performance score. The Ottawa CRM checklist provides 12 items in the five categories of CRM, with a maximum cumulative score of 30 points. Construct validity was measured on the basis of content validity, response process, internal structure, and response to other variables. T-test analysis of Ottawa GRS scores was conducted to examine response to the variable of level of training. Intraclass correlation coefficient (ICC) scores were used to measure inter-rater reliability for both scenarios. Thirty-two first-year and 28 third-year residents participated in the study. Third-year residents produced higher mean scores for overall CRM performance than first-year residents (P CRM checklist (P CRM checklist. Users indicated a strong preference for the Ottawa GRS given ease of scoring, presence of an overall score, and the potential for formative evaluation. Construct validity seems to be present when using both the Ottawa GRS and CRM checklist to evaluate CRM performance during simulated emergencies. Data also indicate the presence of moderate inter-rater reliability when using both the Ottawa GRS and CRM checklist.

  1. Effects of endorphin massage on B-endorphin level and Edinburgh Postnatal Depression Scale (EPDS score in women with postpartum blues

    Directory of Open Access Journals (Sweden)

    Hidayati Hidayati

    2014-06-01

    Results: Endorphin massage treatment significantly increase the B-endorphin level compared to before treatment (P 0.05. The level of EPDS significantly decrease after treatment than that before treatment (P 0.05. There is significantly negative correlation between B-endorphin level and EPDS score (r = -0,517; P 0.05. Conclusion: Endorphin massage is good alternative treatment to increase B-endorphin level and decresae EPDS score among mother with postpartum blues. [Cukurova Med J 2014; 39(3.000: 512-516

  2. High-Efficiency Small-Scale Combined Heat and Power Organic Binary Rankine Cycles

    OpenAIRE

    Costante Mario Invernizzi; Nadeem Ahmed Sheikh

    2018-01-01

    Small-CHP (Combined Heat and Power) systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example) they could play an important role in distributed generation even in developing countries or, in any case, where there are no extensive electricity networks. Traditionally the considered heat engines for micro- or mini-CHP are: the gas eng...

  3. Relationship between the climbing up and climbing down stairs domain scores on the FES-DMD, the score on the Vignos Scale, age and timed performance of functional activities in boys with Duchenne muscular dystrophy

    Directory of Open Access Journals (Sweden)

    Lilian A. Y. Fernandes

    2014-12-01

    Full Text Available BACKGROUND: Knowing the potential for and limitations of information generated using different evaluation instruments favors the development of more accurate functional diagnoses and therapeutic decision-making. OBJECTIVE: To investigate the relationship between the number of compensatory movements when climbing up and going down stairs, age, functional classification and time taken to perform a tested activity (TA of going up and down stairs in boys with Duchenne muscular dystrophy (DMD. METHOD: A bank of movies featuring 30 boys with DMD performing functional activities was evaluated. Compensatory movements were assessed using the climbing up and going down stairs domain of the Functional Evaluation Scale for Duchenne Muscular Dystrophy (FES-DMD; age in years; functional classification using the Vignos Scale (VS, and TA using a timer. Statistical analyses were performed using the Spearman correlation test. RESULTS: There is a moderate relationship between the climbing up stairs domain of the FES-DMD and age (r=0.53, p=0.004 and strong relationships with VS (r=0.72, p=0.001 and TA for this task (r=0.83, p<0.001. There were weak relationships between the going down stairs domain of the FES-DMD-going down stairs with age (r=0.40, p=0.032, VS (r=0.65, p=0.002 and TA for this task (r=0.40, p=0.034. CONCLUSION: These findings indicate that the evaluation of compensatory movements used when climbing up stairs can provide more relevant information about the evolution of the disease, although the activity of going down stairs should be investigated, with the aim of enriching guidance and strengthening accident prevention. Data from the FES-DMD, age, VS and TA can be used in a complementary way to formulate functional diagnoses. Longitudinal studies and with broader age groups may supplement this information.

  4. Thermodynamic, economic and thermo-economic optimization of a new proposed organic Rankine cycle for energy production from geothermal resources

    International Nuclear Information System (INIS)

    Kazemi, Neda; Samadi, Fereshteh

    2016-01-01

    Highlights: • A new cycle was designed to improve basic organic Rankine cycle performance. • Peng Robinson equation of state was used to obtain properties of working fluids. • Operating parameters were optimized with three different objective functions. • Efficiency of new organic Rankine cycle is higher than other considered cycles. • Return on investment of new cycle for Iran is more than France and America. - Abstract: The main goal of this study is to propose and investigate a new organic Rankine cycle based on three considered configurations: basic organic Rankine cycle, regenerative organic Rankine cycle and two-stage evaporator organic Rankine cycle in order to increase electricity generation from geothermal sources. To analyze the considered cycles’ performance, thermodynamic (energy and exergy based on the first and second laws of thermodynamics) and economic (specific investment cost) models are investigated. Also, a comparison of cycles modeling results is carried out in optimum conditions according to different optimization which consist thermodynamic, economic and thermo-economic objective functions for maximizing exergy efficiency, minimizing specific investment cost and applying a multi-objective function in order to maximize exergy efficiency and minimize specific investment cost, respectively. Optimized operating parameters of cycles include evaporators and regenerative temperatures, pinch point temperature difference of evaporators and degree of superheat. Furthermore, Peng Robinson equation of state is used to obtain thermodynamic properties of isobutane and R123 which are selected as dry and isentropic working fluids, respectively. The results of optimization indicate that, thermal and exergy efficiencies increase and exergy destruction decrease especially in evaporators for both working fluids in new proposed organic Rankine cycle compared to the basic organic Rankine cycle. Moreover, the amount of specific investment cost in new

  5. [Religious/spiritual well-being in mentally ill persons II: the development of a short scale and comparison scores for clinical psychiatric groups and healthy controls].

    Science.gov (United States)

    Unterrainer, Human-Friedrich; Kapfhammer, Hans-Peter

    2014-01-01

    The Multidimensional Inventory for Religious/Spiritual Well-Being (MI-RSWB) was successfully applied in several clinical as well as non-clinical studies. However, the original version of the scale often showed to be as too comprehensive especially for clinical surroundings. There for the aim of this study is to develop a short version of the scale comprising 12 items. Based on a sample representative of the Austrian general population (N = 1,500), a first MI-RSWB short version is developed by means of factor- and reliability analysis. Furthermore the new short version of the scale is initially validated through several indicators of mental illness. The MI-RSWB short version shows convincing psychometric properties. The total scale as well as the sub scales exhibit at least a sufficient internal consistency. A significant negative association with several indicators of psychiatric illness is also confirmed for the short version of the scale. The MI-RWSB 12 scale is especially recommended for further research focusing on the clinical relevance of religiosity and spirituality.

  6. Comparison between regenerative organic Rankine cycle (RORC) and basic organic Rankine cycle (BORC) based on thermoeconomic multi-objective optimization considering exergy efficiency and levelized energy cost (LEC)

    International Nuclear Information System (INIS)

    Feng, Yongqiang; Zhang, Yaning; Li, Bingxi; Yang, Jinfu; Shi, Yang

    2015-01-01

    Highlights: • The thermoeconomic comparison of regenerative RORC and BORC is investigated. • The Pareto frontier solution with bi-objective compares with the corresponding single-objective solutions. • The three-objective optimization of the RORC and BORC is studied. • The RORC owns 8.1% higher exergy efficiency and 21.1% more LEC than the BORC under the Pareto-optimal solution. - Abstract: Based on the thermoeconomic multi-objective optimization by using non-dominated sorting genetic algorithm (NSGA-II), considering both thermodynamic performance and economic factors, the thermoeconomic comparison of regenerative organic Rankine cycles (RORC) and basic organic Rankine cycles (BORC) are investigated. The effects of five key parameters including evaporator outlet temperature, condenser temperature, degree of superheat, pinch point temperature difference and degree of supercooling on the exergy efficiency and levelized energy cost (LEC) are examined. Meanwhile, the Pareto frontier solution with bi-objective for maximizing exergy efficiency and minimizing LEC is obtained and compared with the corresponding single-objective solutions. Research demonstrates that there is a significant negative correlation between thermodynamic performance and economic factors. And the optimum exergy efficiency and LEC for the Pareto-optimal solution of the RORC are 55.97% and 0.142 $/kW h, respectively, which are 8.1% higher exergy efficiency and 21.1% more LEC than that of the BORC under considered condition. Highest exergy and thermal efficiencies are accompanied with lowest net power output and worst economic performance. Furthermore, taking the net power output into account, detailed investigation on the three-objective optimization for maximizing exergy efficiency, maximizing net power output and minimizing LEC is discussed

  7. Proposal of a combined heat and power plant hybridized with regeneration organic Rankine cycle: Energy-Exergy evaluation

    International Nuclear Information System (INIS)

    Anvari, Simin; Jafarmadar, Samad; Khalilarya, Shahram

    2016-01-01

    Highlights: • A new thermodynamic cogeneration system is proposed. • Energy and exergy analysis of the considered cycle were performed. • An enhancement of 2.6% in exergy efficiency compared to that of baseline cycle. - Abstract: Among Rankine cycles (simple, reheat and regeneration), regeneration organic Rankine cycle demonstrates higher efficiencies compared to other cases. Consequently, in the present work a regeneration organic Rankine cycle has been utilized to recuperate gas turbine’s heat using heat recovery steam generator. At first, this cogeneration system was subjected to energy and exergy analysis and the obtained results were compared with that of investigated cogeneration found in literature (a cogeneration system in which a reheat organic Rankine cycle for heat recuperation of gas turbine cycle was used with the aid of heat recovery steam generator). Results indicated that the first and second thermodynamic efficiencies in present cycle utilizing regeneration cycle instead of reheat cycle has increased 2.62% and 2.6%, respectively. In addition, the effect of thermodynamic parameters such as combustion chamber’s inlet temperature, gas turbine inlet temperature, evaporator and condenser temperature on the energetic and exergetic efficiencies of gas turbine-heat recovery steam generator cycle and gas turbine-heat recovery steam generator cycle with regeneration organic Rankine cycle was surveyed. Besides, parametric analysis shows that as gas turbine and combustion chamber inlet temperatures increase, energetic and exergetic efficiencies tend to increase. Moreover, once condenser and evaporator temperature raise, a slight decrement in energetic and exergetic efficiency is expected.

  8. Exergy analysis and parameter study on a novel auto-cascade Rankine cycle

    International Nuclear Information System (INIS)

    Bao, Junjiang; Zhao, Li

    2012-01-01

    A novel auto-cascade Rankine cycle (ARC) is proposed to reduce thermodynamics irreversibility and improve energy utilization. Like the Kalina cycle, the working fluid for the ARC is zeotropic mixture, which can improve the system efficiency due to the temperature slip that zeotropic mixtures exhibit during phase change. Unlike the Kalina cycle, two expanders are included in the ARC rather than a expander and a throttling valve in the Kalina cycle, which means more work can be obtained. Using the exhaust gas as the heat source and water as the heat sink, a program is written by Matlab 2010a to carry out exergy analysis and parameter study on the ARC. Results show that the R245fa mass fraction in the primary circuit exists an optimum value with respect to the minimum total cycle irreversibility. The largest exergy loss occurs in evaporator, followed by the superheater, condenser, regenerator and IHE (Internal heat exchanger). As the R245fa mass fraction increases, the exergy losses of different components vary diversely. With the evaporation pressure rises, the total cycle irreversibility decreases and work output increases. Separator temperature has a greater influence on the system performance than superheating temperature. Compared with ORC (organic Rankine cycle) and Kalina cycle in the literature, the ARC has proven to be thermodynamically better. -- Highlights: ► We have proposed a novel auto-cascade Rankine cycle (ARC) system. ► The zeotropic mixture Isopentane/R245fa is employed in this system. ► Exergy analysis and parameter study on the ARC are presented. ► Compared with ORC and Kalina cycle in the literature, the ARC has proven to be thermodynamically better.

  9. A synthesis/design optimization algorithm for Rankine cycle based energy systems

    International Nuclear Information System (INIS)

    Toffolo, Andrea

    2014-01-01

    The algorithm presented in this work has been developed to search for the optimal topology and design parameters of a set of Rankine cycles forming an energy system that absorbs/releases heat at different temperature levels and converts part of the absorbed heat into electricity. This algorithm can deal with several applications in the field of energy engineering: e.g., steam cycles or bottoming cycles in combined/cogenerative plants, steam networks, low temperature organic Rankine cycles. The main purpose of this algorithm is to overcome the limitations of the search space introduced by the traditional mixed-integer programming techniques, which assume that possible solutions are derived from a single superstructure embedding them all. The algorithm presented in this work is a hybrid evolutionary/traditional optimization algorithm organized in two levels. A complex original codification of the topology and the intensive design parameters of the system is managed by the upper level evolutionary algorithm according to the criteria set by the HEATSEP method, which are used for the first time to automatically synthesize a “basic” system configuration from a set of elementary thermodynamic cycles. The lower SQP (sequential quadratic programming) algorithm optimizes the objective function(s) with respect to cycle mass flow rates only, taking into account the heat transfer feasibility constraint within the undefined heat transfer section. A challenging example of application is also presented to show the capabilities of the algorithm. - Highlights: • Energy systems based on Rankine cycles are used in many applications. • A hybrid algorithm is proposed to optimize the synthesis/design of such systems. • The topology of the candidate solutions is not limited by a superstructure. • Topology is managed by the genetic operators of the upper level algorithm. • The effectiveness of the algorithm is proved in a complex test case

  10. [Collateral score based on CT perfusion can predict the prognosis of patients with anterior circulation ischemic stroke after thrombectomy].

    Science.gov (United States)

    Wang, Qingsong; Zhang, Sheng; Zhang, Meixia; Chen, Zhicai; Lou, Min

    2017-07-25

    To evaluate the value of collateral score based on CT perfusion (CTP-CS) in predicting the clinical outcome of patients with anterior circulation ischemic stroke after thrombectomy. Clinical data of acute ischemic stroke patients with anterior artery occlusion undergoing endovascular treatment in the Second Affiliated Hospital, Zhejiang University School of Medicine during October 2013 and October 2016 were retrospectively reviewed. Collateral scores were assessed based on CTP and digital subtraction angiography (DSA) images, respectively. And DSA-CS or CTP-CS 3-4 was defined as good collateral vessels. Good clinical outcome was defined as a modified Rankin Scale (mRS) ≤ 2 at 3 months after stroke. The binary logistic regression model was used to analyze the correlation between the collateral score and clinical outcome, and the receiver operating characteristic (ROC) curve was used to analyze the value of DSA-CS and CTP-CS in predicting the clinical outcome. Among 40 patients, 33 (82.5%) acquired recanalization and 16 (40.0%) got good outcome. Compared with poor outcome group, the collateral score (all P collateral vessels were higher in good outcome group (all P collateral vessels were independent factor of good outcome (CTP-CS: OR =48.404, 95% CI :1.373-1706.585, P Collateral scores based on CTP and DSA had good consistency ( κ =0.697, P <0.01), and ROC curve showed that the predictive value of CTP-CS and DSA-CS were comparable (both AUC=0.726, 95% CI :0.559-0.893, P <0.05). CTP-CS can predict the clinical outcome of patients with anterior circulation ischemic stroke after thrombectomy.

  11. Influence of working fluids on Organic Rankine Cycle for waste heat recovery applications

    Energy Technology Data Exchange (ETDEWEB)

    Struzyna, Ralf; Eifler, Wolfgang; Steinmill, Jens [Bochum Univ. (Germany). Lehrstuhl fuer Verbrennungsmotoren

    2012-11-01

    More than 50% of the energy contained in fuel is lost due to the loss of heat content to the exhaust gas, the cooling water or the charge air cooler medium. Therefore, one of the most promising attempts to further increase the efficiency of internal combustion engines is waste heat recovery by means of a combined process. The Organic Rankine Cycle (ORC) is a promising process for waste heat recovery systems. The main purpose is to identify suitable working fluids to achieve best system performance. Therefore an analysis of the influence of different working fluids on system output is required. (orig.)

  12. Preliminary design package for residential heating/cooling system: Rankine air conditioner redesign

    Science.gov (United States)

    1978-01-01

    A summary of the preliminary redesign and development of a marketable single family heating and cooling system is presented. The interim design and schedule status of the residential (3-ton) redesign, problem areas and solutions, and the definition of plans for future design and development activities were discussed. The proposed system for a single-family residential heating and cooling system is a single-loop, solar-assisted, hydronic-to-warm-air heating subsystem with solar-assisted domestic water heating and a Rankine-driven expansion air-conditioning subsystem.

  13. Panel cutting method: new approach to generate panels on a hull in Rankine source potential approximation

    Directory of Open Access Journals (Sweden)

    Hee-Jong Choi

    2011-12-01

    Full Text Available In the present study, a new hull panel generation algorithm, namely panel cutting method, was developed to predict flow phenomena around a ship using the Rankine source potential based panel method, where the iterative method was used to satisfy the nonlinear free surface condition and the trim and sinkage of the ship was taken into account. Numerical computations were performed to investigate the validity of the proposed hull panel generation algorithm for Series 60 (CB=0.60 hull and KRISO container ship (KCS, a container ship designed by Maritime and Ocean Engineering Research Institute (MOERI. The computational results were validated by comparing with the existing experimental data.

  14. Panel cutting method: new approach to generate panels on a hull in Rankine source potential approximation

    Science.gov (United States)

    Choi, Hee-Jong; Chun, Ho-Hwan; Park, Il-Ryong; Kim, Jin

    2011-12-01

    In the present study, a new hull panel generation algorithm, namely panel cutting method, was developed to predict flow phenomena around a ship using the Rankine source potential based panel method, where the iterative method was used to satisfy the nonlinear free surface condition and the trim and sinkage of the ship was taken into account. Numerical computations were performed to investigate the validity of the proposed hull panel generation algorithm for Series 60 (CB=0.60) hull and KRISO container ship (KCS), a container ship designed by Maritime and Ocean Engineering Research Institute (MOERI). The computational results were validated by comparing with the existing experimental data.

  15. Design and optimization of a novel organic Rankine cycle with improved boiling process

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, U.; Knudsen, Thomas

    2015-01-01

    to improve the boiling process. Optimizations are carried out for eight hydrocarbon mixtures for hot fluid inlet temperatures at 120 °C and 90 °C, using a genetic algorithm to determine the cycle conditions for which the net power output is maximized. The most promising mixture is an isobutane....../pentane mixture which, for the 90 °C hot fluid inlet temperature case, achieves a 14.5% higher net power output than an optimized organic Rankine cycle using the same mixture. Two parameter studies suggest that optimum conditions for the organic split-cycle are when the temperature profile allows the minimum...

  16. Evaluation of Rankine cycle air conditioning system hardware by computer simulation

    Science.gov (United States)

    Healey, H. M.; Clark, D.

    1978-01-01

    A computer program for simulating the performance of a variety of solar powered Rankine cycle air conditioning system components (RCACS) has been developed. The computer program models actual equipment by developing performance maps from manufacturers data and is capable of simulating off-design operation of the RCACS components. The program designed to be a subroutine of the Marshall Space Flight Center (MSFC) Solar Energy System Analysis Computer Program 'SOLRAD', is a complete package suitable for use by an occasional computer user in developing performance maps of heating, ventilation and air conditioning components.

  17. Applying the principles of thermoeconomics to the organic Rankine Cycle for low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Xiao, F.; Lilun, Q.; Changsun, S.

    1989-01-01

    In this paper, thermoeconomic principle is used to study the selection of working fluids and the option of the cycle parameters in the organic Rankine cycle of low temperature waste heat recovery. The parameter ξ, the product of the ratio of waste heat recovery and real cycle thermal efficiency, is suggested as a unified thermodynamic criterion for the selection of the working fluids. The mathematical expressions are developed to determine the optimal boiling temperature and the optimal pin point temperature difference in the heat recovery exchanger by way of thermoeconomic principle

  18. A study of organic working fluids of an organic Rankine cycle for solar concentrating power plant

    International Nuclear Information System (INIS)

    Saifaoui, D.; Elmaanaoui, Y.; Faik, A.

    2014-01-01

    This work is a comparative study between four different configurations of an organic Rankine cycle (ORC) in order to find the configuration that gives the best performances. This study also made a comparison between seven organic fluids used as working fluids in the four ORC configurations. These fluids are all hydrocarbons. Then we made a parametric analysis of the results obtained in this first part. In a second part, we developed the binary mixtures of the seven pure hydrocarbons with the NIST software REFPROP 9 and we used them in our four ORC configurations. The obtained results are given and discussed. (author)

  19. Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

    Science.gov (United States)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

  20. Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

    Science.gov (United States)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

  1. Model based control for waste heat recovery rankine cycle system in heavy duty trucks

    OpenAIRE

    Grelet, Vincent; Dufour, Pascal; Nadri, Madiha; Lemort, Vincent; Reiche, Thomas

    2015-01-01

    Driven by future emissions legislations and increase in fuel prices engine, gas heat recovering has recently attracted a lot of interest. In the past few years, a high number of studies have shown the interest of energy recovery Rankine based systems for heavy duty trucks engine compounding. Recent studies have brought a significant potential for such a system in a Heavy Duty (HD) vehicle, which can lead to a decrease in fuel consumption of about 5% [Wang et al. (2011)] and reduce engine emis...

  2. Experimental Comparison Of Working Fluids For Organic Rankine Cycle With Single-Screw Expander

    OpenAIRE

    Gusev, Sergei; Ziviani, Davide; Bell, Ian; De Paepe, Michel; van den Broek, Martijn

    2014-01-01

    This paper describes the behavior of an Organic Rankine Cycle (ORC) fed by a heat source with adaptable temperature and mass flow. For a suitable choice of working fluid, the setting of its evaporation pressure is crucial for the performance of an ORC installation. The higher the evaporation pressure, the higher the cycle efficiency on the one hand, but the lower the energy recovered from the heat source due to a higher outlet temperature on the other hand. An optimum has to be found to achie...

  3. A Novel Organic Rankine Cycle System with Improved Thermal Stability and Low Global Warming Fluids

    Directory of Open Access Journals (Sweden)

    Panesar Angad S

    2014-07-01

    Full Text Available This paper proposes a novel Organic Rankine Cycle (ORC system for long haul truck application. Rather than typical tail pipe heat recovery configurations, the proposed setup exploits the gaseous streams that are already a load on the engine cooling module. The system uses dual loops connected only by the Exhaust Gas Recirculation (EGR stream. A water blend study is conducted to identify suitable mixtures for the High Temperature (HT loop, while the Low Temperature (LT loop utilises a Low Global Warming (GWP Hydrofluoroether.

  4. Technology for industrial waste heat recovery by organic Rankine cycle systems

    Science.gov (United States)

    Cain, W. G.; Drake, R. L.; Prisco, C. J.

    1984-10-01

    The recovery of industrial waste heat and the conversion thereof to useful electric power by use of Rankine cycle systems is studied. Four different aspects of ORC technology were studied: possible destructive chemical reaction between an aluminum turbine wheel and R-113 working fluid under wheel-to-rotor rub conditions; possible chemical reaction between stainless steel or carbon steel and any of five different ORC working fluids under rotor-stator rub conditions; effects on electric generator properties of extended exposure to an environment of saturated R-113 vapor/fluid; and operational proof tests under laboratory conditions of two 1070 kW, ORC, R-113 hermetic turbogenerator power module systems.

  5. Conceptual design and analysis of a Dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.

    1980-08-01

    A Point Focusing Distributed Receiver (PFDR) solar thermal electric system which employs small Organic Rankine Cycle (ORC) engines is examined with reference to its projected technical/economic performance. With mass-produced power modules (about 100,000 per year), the projected life-cycle energy cost for an optimized no-storage system is estimated at 67 mills/kWh (Levelized Busbar Energy Cost) without the need for advanced development of any of its components. At moderate production rates (about 50 MWe/yr) system energy costs are competitive with conventional power generation systems in special remote-site types of applications.

  6. Thermal energy storage for organic Rankine cycle solar dynamic space power systems

    Science.gov (United States)

    Heidenreich, G. R.; Parekh, M. B.

    An organic Rankine cycle-solar dynamic power system (ORC-SDPS) comprises a concentrator, a radiator, a power conversion unit, and a receiver with a thermal energy storage (TES) subsystem which charges and discharges energy to meet power demands during orbital insolation and eclipse periods. Attention is presently given to the criteria used in designing and evaluating an ORC-SDPS TES, as well as the automated test facility employed. It is found that a substantial data base exists for the design of an ORC-SDPS TES subsystem.

  7. Preliminary design package for residential heating/cooling system--Rankine air conditioner redesign

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    This report contains a summary of the preliminary redesign and development of a marketable single-family heating and cooling system. The objectives discussed are the interim design and schedule status of the Residential (3-ton) redesign, problem areas and solutions, and the definition of plans for future design and development activities. The proposed system for a single-family residential heating and cooling system is a single-loop, solar-assisted, hydronic-to-warm-air heating subsystem with solar-assisted domestic water heating and a Rankine-driven expansion air-conditioning subsystem.

  8. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2016-01-01

    , which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important......For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers...

  9. Multi-objective optimization of organic Rankine cycle power plants using pure and mixed working fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermalphase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cyclepower plants enables a minimization of the mean temperature difference of the heat exchangers whenthe...... minimum pinch point temperature difference is kept fixed. A low mean temperature differencemeans low heat transfer irreversibilities, which is beneficial for cycle performance, but it also results inlarger heat transfer surface areas. Moreover, the two-phase heat transfer coefficients for zeotropic...

  10. Thermodynamic analysis of an integrated gasification solid oxide fuel cell plant combined with an organic Rankine cycle

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Rokni, Masoud; Larsen, Ulrik

    2013-01-01

    into a fixed bed gasification plant to produce syngas which fuels the combined solid oxide fuel cells e organic Rankine cycle system to produce electricity. More than a hundred fluids are considered as possible alternative for the organic cycle using non-ideal equations of state (or state-of-the-art equations......A 100 kWe hybrid plant consisting of gasification system, solid oxide fuel cells and organic Rankine cycle is presented. The nominal power is selected based on cultivation area requirement. For the considered output a land of around 0.5 km2 needs to be utilized. Woodchips are introduced...... achieved by simple and double stage organic Rankine cycle plants and around the same efficiency of a combined gasification, solid oxide fuel cells and micro gas turbine plant. © 2013 Elsevier Ltd. All rights reserved....

  11. Thermodynamic performance analysis of a coupled transcritical and subcritical organic Rankine cycle system for waste heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xi Wu [Zhejiang Ocean University, Zhejian (China); Wang, Xiao Qiong; Li, You Rong; Wu, Chun Mei [Chongqing University, Chongqing (China)

    2015-07-15

    We present a novel coupled organic Rankine cycle (CORC) system driven by the low-grade waste heat, which couples a transcritical organic Rankine cycle with a subcritical organic Rankine cycle. Based on classical thermodynamic theory, a detailed performance analysis on the novel CORC system was performed. The results show that the pressure ratio of the expander is decreased in the CORC and the selection of the working fluids becomes more flexible and abundant. With the increase of the pinch point temperature difference of the internal heat exchanger, the net power output and thermal efficiency of the CORC all decrease. With the increase of the critical temperature of the working fluid, the system performance of the CORC is improved. The net power output and thermal efficiency of the CORC with isentropic working fluids are higher than those with dry working fluids.

  12. Validación de los Puntajes de Corte del MACI a través de las Escalas Clínicas del MMPI-A Validation of Cutoff Scores for MACI Using the MMPI-A Clinical Scales

    Directory of Open Access Journals (Sweden)

    Eugenia V Vinet

    2009-01-01

    Full Text Available Inserta en el proyecto de desarrollo de normas chilenas del MACI, se reporta la validación concurrente de los puntajes de corte de las escalas del MACI, utilizando como criterio las escalas clínicas del MMPI-A. Las puntuaciones MMPI-A de los participantes de la muestra de baremación del MACI (n = 807 fueron analizadas a través de una serie de MANOVAS y ANO VAS que diferenciaron significativamente a los grupos de funcionamiento sano y funcionamiento alterado creados a partir de la segmentación de la muestra total según el puntaje de corte de cada escala. La discusión destaca la congruencia de la diferenciación realizada por el MMPI-A y sus aportes a la mejor comprensión de las escalas MACI.Inserted in a project for building Chilean norms for the MACI, the concurrent validation of the cutoff scores of MACI is reported, using as a criterion the MMPI-A scores obtained by the MACI normative sample (n = 807. Data were analyzed through a set of MANOVAS and ANO VAS that allowed significant differentiation between healthy functioning and disorderly functioning groups that were created by dividing the sample on the basis of cutoff scores for each scale. Discussion emphasizes the congruence of MMPI-A results and its contribution to the better understanding of MACI scales.

  13. Preliminary thermodynamic study for an efficient turbo-blower external combustion Rankine cycle

    Science.gov (United States)

    Romero Gómez, Manuel; Romero Gómez, Javier; Ferreiro Garcia, Ramón; Baaliña Insua, Álvaro

    2014-08-01

    This research paper presents a preliminary thermodynamic study of an innovative power plant operating under a Rankine cycle fed by an external combustion system with turbo-blower (TB). The power plant comprises an external combustion system for natural gas, where the combustion gases yield their thermal energy, through a heat exchanger, to a carbon dioxide Rankine cycle operating under supercritical conditions and with quasi-critical condensation. The TB exploits the energy from the pressurised exhaust gases for compressing the combustion air. The study is focused on the comparison of the combustion system's conventional technology with that of the proposed. An energy analysis is carried out and the effect of the flue gas pressure on the efficiency and on the heat transfer in the heat exchanger is studied. The coupling of the TB results in an increase in efficiency and of the convection coefficient of the flue gas with pressure, favouring a reduced volume of the heat exchanger. The proposed innovative system achieves increases in efficiency of around 12 % as well as a decrease in the heat exchanger volume of 3/5 compared with the conventional technology without TB.

  14. Off-design performance analysis of a solar-powered organic Rankine cycle

    International Nuclear Information System (INIS)

    Wang, Jiangfeng; Yan, Zhequan; Zhao, Pan; Dai, Yiping

    2014-01-01

    Highlights: • Solar-powered organic Rankine cycle with CPC and thermal storage unit is studied. • Off-design performances encountering the changes of key parameters are examined. • Off-design performance is analyzed over a whole day and in different months. - Abstract: Performance evaluation of a thermodynamic system under off-design conditions is very important for reliable and cost-effective operation. In this study, an off-design model of an organic Rankine cycle driven by solar energy is established with compound parabolic collector (CPC) to collect the solar radiation and thermal storage unit to achieve the continuous operation of the overall system. The system off-design behavior is examined under the change in environment temperature, as well as thermal oil mass flow rates of vapor generator and CPC. In addition, the off-design performance of the system is analyzed over a whole day and in different months. The results indicate that a decrease in environment temperature, or the increases in thermal oil mass flow rates of vapor generator and CPC could improve the off-design performance. The system obtains the maximum average exergy efficiency in December and the maximum net power output in June or in September. Both the net power output and the average exergy efficiency reach minimum values in August

  15. An integrated optimization for organic Rankine cycle based on entransy theory and thermodynamics

    International Nuclear Information System (INIS)

    Li, Tailu; Fu, Wencheng; Zhu, Jialing

    2014-01-01

    The organic Rankine cycle has been one of the essential heat-work conversion technologies nowadays. Lots of effectual optimization methods are focused on the promotion of the system efficiency, which are mainly relied on engineering experience and numerical simulations rather than theoretical analysis. A theoretical integrated optimization method was established based on the entransy theory and thermodynamics, with the ratio of the net power output to the ratio of the total thermal conductance to the thermal conductance in the condenser as the objective function. The system parameters besides the optimal pinch point temperature difference were obtained. The results show that the mass flow rate of the working fluid is inversely proportional to the evaporating temperature. An optimal evaporating temperature maximizes the net power output, and the maximal net power output corresponds to the maximal entransy loss and the change points of the heat source outlet temperature and the change rates for the entropy generation and the entransy dissipation. Moreover, the net power output and the total thermal conductance are inversely proportional to the pinch point temperature difference, contradicting with each other. Under the specified condition, the optimal operating parameters are ascertained, with the optimal pinch point temperature difference of 5 K. - Highlights: • We establish an integrated optimization model for organic Rankine cycle. • The model combines the entransy theory with thermodynamics. • The maximal net power output corresponds to the maximal entransy loss. • The pinch point temperature difference is optimized to be 5 K

  16. Selecting working fluids in an organic Rankine cycle for power generation from low temperature heat sources

    Directory of Open Access Journals (Sweden)

    Fredy Vélez

    2014-01-01

    Full Text Available Este trabajo presenta un estudio termodinámico realizado sobre el uso de fuentes de calor de baja temperatura para la generaci ón de energía a través de un ciclo Rankin e subcrítico con fluidos de trabajo orgánicos. Un análisis d el estado del arte de esta tecn ología muestra como línea de investigación abierta, la selección del fluido de trabajo, pues hasta ahora, no existe un fluido que satisfaga t odos los aspectos medioambientales y técnicos a tener en cuenta en estos ciclos. Por ello, se ha desarrollado una serie de simulaciones que permiten estudiar el comportamiento del ciclo Rankine con difer entes configuraciones y fluidos (húmedo, seco e isoentrópico, permitiendo con ello observar de qué manera influyen cambios ta nto en esos tipos de fluidos utilizados (refrigerantes, hidroca rburos y agua, como de condiciones de temperatura, presión, flujo, etc. , sobre la eficiencia total del ciclo. Con el trabajo realizado se demuestra la viabilidad de este tipo de proceso en la recuperación de calore s en la industria y/o aprovechamiento de fuentes renovables de baja y media temperatura para la producción de energía eléctrica.

  17. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  18. Simulation of a passive house coupled with a heat pump/organic Rankine cycle reversible unit

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Randaxhe, François

    2014-01-01

    This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible ...... presents a higher global COP because the heat produced on the roof can heat the storage directly.......This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible...... modes that need to be chosen optimally depending on the weather conditions, the heat demand and the temperature level of the storage. The ORC mode is activated, as long as the heat demand of the house is covered by the storage to produce electricity based upon the heat generated by the solar roof...

  19. Review of organic Rankine cycles for internal combustion engine exhaust waste heat recovery

    International Nuclear Information System (INIS)

    Sprouse, Charles; Depcik, Christopher

    2013-01-01

    Escalating fuel prices and future carbon dioxide emission limits are creating a renewed interest in methods to increase the thermal efficiency of engines beyond the limit of in-cylinder techniques. One promising mechanism that accomplishes both objectives is the conversion of engine waste heat to a more useful form of energy, either mechanical or electrical. This paper reviews the history of internal combustion engine exhaust waste heat recovery focusing on Organic Rankine Cycles since this thermodynamic cycle works well with the medium-grade energy of the exhaust. Selection of the cycle expander and working fluid are the primary focus of the review, since they are regarded as having the largest impact on system performance. Results demonstrate a potential fuel economy improvement around 10% with modern refrigerants and advancements in expander technology. -- Highlights: ► This review article focuses on engine exhaust waste heat recovery works. ► The organic Rankine cycle is superior for low to medium exergy heat sources. ► Working fluid and expander selection strongly influence efficiency. ► Several authors demonstrate viable systems for vehicle installation

  20. Selection of Optimum Working Fluid for Organic Rankine Cycles by Exergy and Exergy-Economic Analyses

    Directory of Open Access Journals (Sweden)

    Kamyar Darvish

    2015-11-01

    Full Text Available The thermodynamic performance of a regenerative organic Rankine cycle that utilizes low temperature heat sources to facilitate the selection of proper organic working fluids is simulated. Thermodynamic models are used to investigate thermodynamic parameters such as output power, and energy efficiency of the ORC (Organic Rankine Cycle. In addition, the cost rate of electricity is examined with exergo-economic analysis. Nine working fluids are considered as part of the investigation to assess which yields the highest output power and exergy efficiency, within system constraints. Exergy efficiency and cost rate of electricity are used as objective functions for system optimization, and each fluid is assessed in terms of the optimal operating condition. The degree of superheat and the pressure ratio are independent variables in the optimization. R134a and iso-butane are found to exhibit the highest energy and exergy efficiencies, while they have output powers in between the systems using other working fluids. For a source temperature was equal to 120 °C, the exergy efficiencies for the systems using R134a and iso-butane are observed to be 19.6% and 20.3%, respectively. The largest exergy destructions occur in the boiler and the expander. The electricity cost rates for the system vary from 0.08 USD/kWh to 0.12 USD/kWh, depending on the fuel input cost, for the system using R134a as a working fluid.

  1. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    Directory of Open Access Journals (Sweden)

    Jesper G. Andreasen

    2016-04-01

    Full Text Available For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low-temperature heat at 90 ∘ C to produce electrical power at around 500 kW. The primary outcomes of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a (0.65/0.35 mole . The results indicate that R32/R134a is the best of these fluids, with 3.4 % higher net power than R32 at the same total cost of 1200 k$.

  2. A confirmatory test of the underlying factor structure of scores on the collective self-esteem scale in two independent samples of Black Americans.

    Science.gov (United States)

    Utsey, Shawn O; Constantine, Madonna G

    2006-04-01

    In this study, we examined the factor structure of the Collective Self-Esteem Scale (CSES; Luhtanen & Crocker, 1992) across 2 separate samples of Black Americans. The CSES was administered to a sample of Black American adolescents (n = 538) and a community sample of Black American adults (n = 313). Results of confirmatory factor analyses (CFAs), however, did not support the original 4-factor model identified by Luhtanen and Crocker (1992) as providing an adequate fit to the data for these samples. Furthermore, an exploratory CFA procedure failed to find a CSES factor structure that could be replicated across the 2 samples of Black Americans. We present and discuss implications of the findings.

  3. Parametric and exergetic analysis of waste heat recovery system based on thermoelectric generator and organic rankine cycle utilizing R123

    International Nuclear Information System (INIS)

    Shu, Gequn; Zhao, Jian; Tian, Hua; Liang, Xingyu; Wei, Haiqiao

    2012-01-01

    The paper analyzes the combined TEG-ORC (thermoelectric generator and organic rankine cycle) used in exhaust heat recovery of ICE (internal combustion engine) theoretically. A theoretical model is proposed to calculate the optimal parameters of the bottoming cycle based on thermodynamic theory when net output power and volumetric expansion ratio are selected as objective functions, which affect system performance and size. The effects of relative TEG flow direction, TEG scale, highest temperature, condensation temperature, evaporator pressure and efficiency of IHE (internal heat exchanger) on system performance are investigated. R123 is chosen among the fluids whose decomposition temperature exceeds 600 K to avoid fluid resolving and resulting in wet stroke when expansion process ends. The thermodynamic irreversibility that occurs in evaporator, turbine, IHE, condenser, pump and TEG is revealed at target working areas. The results indicate a significant increase of system performance when TEG and IHE are combined with ORC bottoming cycle. It is also suggested that TEG-ORC system is suitable to recovering waste heat from engines, because TEG can extend the temperature range of heat source and thereby improve the security and fuel economy of engines. -- Highlights: ► Development of a TEG-ORC system using R123 as working fluid for WHR of engines. ► Performance of the developed cycle was investigated theoretically. ► Optimization of configurations and parameters can be obtained. ► Irreversibility in the evaporator, turbine, IHE, condenser, pump and TEG is revealed. ► Optimal net power and indicated efficiency is 27 kW and 45.7%, respectively.

  4. Comparison of a Novel Organic-Fluid Thermofluidic Heat Converter and an Organic Rankine Cycle Heat Engine

    Directory of Open Access Journals (Sweden)

    Christoph J.W. Kirmse

    2016-06-01

    Full Text Available The Up-THERM heat converter is an unsteady, two-phase thermofluidic oscillator that employs an organic working fluid, which is currently being considered as a prime-mover in small- to medium-scale combined heat and power (CHP applications. In this paper, the Up-THERM heat converter is compared to a basic (sub-critical, non-regenerative organic Rankine cycle (ORC heat engine with respect to their power outputs, thermal efficiencies and exergy efficiencies, as well as their capital and specific costs. The study focuses on a pre-specified Up-THERM design in a selected application, a heat-source temperature range from 210 °C to 500 °C and five different working fluids (three n-alkanes and two refrigerants. A modeling methodology is developed that allows the above thermo-economic performance indicators to be estimated for the two power-generation systems. For the chosen applications, the power output of the ORC engine is generally higher than that of the Up-THERM heat converter. However, the capital costs of the Up-THERM heat converter are lower than those of the ORC engine. Although the specific costs (£/kW of the ORC engine are lower than those of the Up-THERM converter at low heat-source temperatures, the two systems become progressively comparable at higher temperatures, with the Up-THERM heat converter attaining a considerably lower specific cost at the highest heat-source temperatures considered.

  5. Numerical Analysis of an Organic Rankine Cycle with Adjustable Working Fluid Composition, a Volumetric Expander and a Recuperator

    Directory of Open Access Journals (Sweden)

    Peter Collings

    2017-03-01

    Full Text Available Conventional Organic Rankine Cycles (ORCs using ambient air as their coolant cannot fully utilize the greater temperature differential available to them during the colder months. However, changing the working fluid composition so its boiling temperature matches the ambient temperature as it changes has been shown to have potential to increase year-round electricity generation. Previous research has assumed that the cycle pressure ratio is able to vary without a major loss in the isentropic efficiency of the turbine. This paper investigates if small scale ORC systems that normally use positive-displacement expanders with fixed expansion ratios could also benefit from this new concept. A numerical model was firstly established, based on which a comprehensive analysis was then conducted. The results showed that it can be applied to systems with positive-displacement expanders and improve their year-round electricity generation. However, such an improvement is less than that of the systems using turbine expanders with variable expansion ratios. Furthermore, such an improvement relies on heat recovery via the recuperator. This is because expanders with a fixed expansion ratio have a relatively constant pressure ratio between their inlet and outlet. The increase of pressure ratio between the evaporator and condenser by tuning the condensing temperature to match colder ambient condition in winter cannot be utilised by such expanders. However, with the recuperator in place, the higher discharging temperature of the expander could increase the heat recovery and consequently reduce the heat input at the evaporator, increasing the thermal efficiency and the specific power. The higher the amount of heat energy transferred in the recuperator, the higher the efficiency improvement.

  6. External validation of the DRAGON score in an elderly Spanish population: prediction of stroke prognosis after IV thrombolysis.

    Science.gov (United States)

    Giralt-Steinhauer, Eva; Rodríguez-Campello, Ana; Cuadrado-Godia, Elisa; Ois, Ángel; Jiménez-Conde, Jordi; Soriano-Tárraga, Carolina; Roquer, Jaume

    2013-01-01

    Intravenous (i.v.) thrombolysis within 4.5 h of symptom onset has proven efficacy in acute ischemic stroke treatment, although half of all outcomes are unfavorable. The recently published DRAGON score aims to predict the 3-month outcome in stroke patients who have received i.v. alteplase. The purpose of this study was an external validation of the results of the DRAGON score in a Spanish cohort. Patients with acute stroke treated with alteplase were prospectively registered in our BasicMar database. We collected demographic characteristics, vascular risk factors, the time from stroke onset to treatment, baseline serum glucose levels and stroke severity for this population. We then reviewed hyperdense cerebral artery signs and signs of early infarct on the admission CT scan. We calculated the DRAGON score and used the developers' 3-month prognosis categories: good [modified Rankin Scale score (mRS) 0-2], poor (mRS 3-6) and miserable (mRS 5-6) outcome. Discrimination was tested using the area under the receiver operator curve (AUC-ROC). Calibration was assessed by the Hosmer-Lemeshow test. Our final cohort of 297 patients was older (median age 74 years, IQR 65-80) and had more risk factors and severe strokes [median National Institutes of Health Stroke Scale (NIHSS) points 13, IQR 7-19] than the original study population. Poor prognosis was observed in 143 (48.1%) patients. Higher DRAGON scores were associated with a higher risk of poor prognosis. None of our treated stroke patients with a DRAGON score ≥8 at admission experienced a favorable outcome after 3 months. All DRAGON variables were significantly associated with a worse outcome in the multivariate analysis except for onset-to-treatment time (p = 0.334). Discrimination to predict poor prognosis was very good (AUC-ROC 0.84) and the score had good Hosmer-Lemeshow calibration (p = 0.84). The DRAGON score is easy to perform and offers a rapid, reliable prediction of poor prognosis in acute-stroke patients

  7. Optimization of the ship type using waveform by means of Rankine source method; Rankine source ho ni yoru hakei wo mochiita funagata saitekika ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, A; Eguchi, T [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

    1996-04-10

    Among the numerical calculation methods for steady-state wave-making problems, the panel shift Rankine source (PSRS) method has the advantages of rather precise determination of wave pattern of practical ship types, and short calculation period. The wave pattern around the hull was calculated by means of the PSRS method. The waveform analysis was carried out for the wave, to obtain an amplitude function of the original ship type. Based on the amplitude function, a ship type improvement method aiming at the optimization of ship type was provided using a conditional calculus of variation. A Series 60 (Cb=0.6) ship type was selected for the ship type improvement, to apply this technique. It was suggested that optimum design can be made for reducing the wave making resistance by means of this method. For the improvement of Series 60 ship type using this method, a great degree of reduction in the wave making resistance was recognized from the results of numerical waveform analysis. It was suggested that the ship type improvement aiming at the reduction of wave-making resistance can be made in shorter period and by smaller labor compared with the method using a waveform analysis of cistern tests. 5 refs., 9 figs.

  8. Analysis of long-term (median 10.5 years) outcomes in children presenting with traumatic brain injury and an initial Glasgow Coma Scale score of 3 or 4.

    Science.gov (United States)

    Fulkerson, Daniel H; White, Ian K; Rees, Jacqueline M; Baumanis, Maraya M; Smith, Jodi L; Ackerman, Laurie L; Boaz, Joel C; Luerssen, Thomas G

    2015-10-01

    Patients with traumatic brain injury (TBI) with low presenting Glasgow Coma Scale (GCS) scores have very high morbidity and mortality rates. Neurosurgeons may be faced with difficult decisions in managing the most severely injured (GCS scores of 3 or 4) patients. The situation may be considered hopeless, with little chance of a functional recovery. Long-term data are limited regarding the clinical outcome of children with severe head injury. The authors evaluate predictor variables and the clinical outcomes at discharge, 1 year, and long term (median 10.5 years) in a cohort of children with TBI presenting with postresuscitation GCS scores of 3 and 4. A review of a prospectively collected trauma database was performed. Patients treated at Riley Hospital for Children (Indianapolis, Indiana) from 1988 to 2004 were reviewed. All children with initial GCS (modified for pediatric patients) scores of 3 or 4 were identified. Patients with a GCS score of 3 were compared with those with a GCS score of 4. The outcomes of all patients at the time of death or discharge and at 1-year and long-term follow-up were measured with a modified Glasgow Outcome Scale (GOS) that included a "normal" outcome. Long-term outcomes were evaluated by contacting surviving patients. Statistical "classification trees" were formed for survival and outcome, based on predictor variables. Sixty-seven patients with a GCS score of 3 or 4 were identified in a database of 1636 patients (4.1%). Three of the presenting factors differed between the GCS 3 patients (n = 44) and the GCS 4 patients (n = 23): presence of hypoxia, single seizure, and open basilar cisterns on CT scan. The clinical outcomes were statistically similar between the 2 groups. In total, 48 (71.6%) of 67 patients died, remained vegetative, or were severely disabled by 1 year. Eight patients (11.9%) were normal at 1 year. Ten of the 22 patients with long-term follow-up were either normal or had a GOS score of 5. Multiple clinical

  9. Analysis of vehicle exhaust waste heat recovery potential using a Rankine cycle

    International Nuclear Information System (INIS)

    Domingues, António; Santos, Helder; Costa, Mário

    2013-01-01

    This study evaluates the vehicle exhaust WHR (waste heat recovery) potential using a RC (Rankine cycle ). To this end, both a RC thermodynamic model and a heat exchanger model have been developed. Both models use as input, experimental data obtained from a vehicle tested on a chassis dynamometer. The thermodynamic analysis was performed for water, R123 and R245fa and revealed the advantage of using water as the working fluid in applications of thermal recovery from exhaust gases of vehicles equipped with a spark-ignition engine. Moreover, the heat exchanger effectiveness for the organic working fluids R123 and R245fa is higher than that for the water and, consequently, they can also be considered appropriate for use in vehicle WHR applications through RCs when the exhaust gas temperatures are relatively low. For an ideal heat exchanger, the simulations revealed increases in the internal combustion engine thermal and vehicle mechanical efficiencies of 1.4%–3.52% and 10.16%–15.95%, respectively, while for a shell and tube heat exchanger, the simulations showed an increase of 0.85%–1.2% in the thermal efficiency and an increase of 2.64%–6.96% in the mechanical efficiency for an evaporating pressure of 2 MPa. The results confirm the advantages of using the thermal energy contained in the vehicle exhaust gases through RCs. Furthermore, the present analysis demonstrates that improved evaporator designs and appropriate expander devices allowing for higher evaporating pressures are required to obtain the maximum WHR potential from vehicle RC systems. -- Highlights: ► This study evaluates the vehicle exhaust waste heat recovery potential using Rankine cycle systems. ► A thermodynamic model and a heat exchanger model were developed. ► Experimental data obtained in a vehicle tested on a chassis dynamometer was used as models input. ► Thermodynamic analysis was performed for water, R123 and R245fa. ► Results confirm advantages of using the thermal energy

  10. Selection and optimization of pure and mixed working fluids for low grade heat utilization using organic Rankine cycles

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, Ulrik; Knudsen, Thomas

    2014-01-01

    We present a generic methodology for organic Rankine cycle optimization, where the working fluid is included as an optimization parameter, in order to maximize the net power output of the cycle. The method is applied on two optimization cases with hot fluid inlet temperatures at 120°C and 90°C. P...

  11. Design and optimisation of organic Rankine cycles for waste heat recovery in marine applications using the principles of natural selection

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Haglind, Fredrik

    2013-01-01

    , boundary conditions, hazard levels and environmental concerns. A generally applicable methodology, based on the principles of natural selection, is presented and used to determine the optimum working fluid, boiler pressure and Rankine cycle process layout for scenarios related to marine engine heat...

  12. CT Angiography and Presentation NIH stroke Scale in Predicting TIA in Patients Presenting with Acute Stroke Symptoms.

    Science.gov (United States)

    Karaman, Bedriye; Selph, James; Burdine, Joselyn; Graham, Cole Blease; Sen, Souvik

    2013-11-08

    Patient candidacy for acute stroke intervention, is currently assessed using brain computed tomography angiography (CTA) evidence of significant stenosis/occlusion (SSO) with a high National Institutes of Health Stroke Scale (NIHSS) (>6). This study examined the association between CTA without significant stenosis/occlusion (NSSO) and lower NIHSS (≤ 6) with transient ischemic attack (TIA) and other good clinical outcomes at discharge. Patients presenting TIA, modified Rankin Score [mRS] ≤ 1, and home as the discharge disposition. Eighty-five patients received both an NIHSS at presentation and a CTA at 4.2 ± 2.2 hours from stroke symptom onset. Patients with NSSO on CTA as well as those with NIHSS≤6 had better outcomes at discharge (pTIA (pTIA. Addition of NIHSS ≤ 6 to NSSO on CTA proved to be a stronger independent predictor of TIA (Adjusted OR 18.7 95% CI: 3.5-98.9, p=0.001).

  13. From Rasch scores to regression

    DEFF Research Database (Denmark)

    Christensen, Karl Bang

    2006-01-01

    Rasch models provide a framework for measurement and modelling latent variables. Having measured a latent variable in a population a comparison of groups will often be of interest. For this purpose the use of observed raw scores will often be inadequate because these lack interval scale propertie....... This paper compares two approaches to group comparison: linear regression models using estimated person locations as outcome variables and latent regression models based on the distribution of the score....

  14. Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

    2016-01-01

    of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output......This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC....... The net power outputs of all the feasible working fluids were ranked including their uncertainties. The method could propagate and quantify the input property uncertainty of the fluidproperty parameters to the ORC model, giving an additional dimension to the fluid selection process. In the given analysis...

  15. Comparative investigation of working fluids for an organic Rankine cycle with geothermal water

    Directory of Open Access Journals (Sweden)

    Liu Yan-Na

    2015-06-01

    Full Text Available In this paper, the thermodynamic investigation on the use of geothermal water (130 °C as maximum for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.

  16. Organic Rankine cycle unit for waste heat recovery on ships (PilotORC)

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Montagud, Maria E. Mondejar; Andreasen, Jesper Graa

    The project PilotORC was aimed at evaluating the technical and economic feasibility of the use of organic Rankine cycle (ORC) units to recover low-temperature waste heat sources (i.e. exhaust gases, scavenge air, engine cooling system, and lubricant oil system) on container vessels. The project...... included numerical simulations and experimental tests on a 125 kW demonstration ORC unit that utilizes the waste heat of the main engine cooling system on board one of Mærsk's container vessels. During the design of the demonstration ORC unit, different alternatives for the condenser were analyzed in order...... of using ORC units for maritime applications, and the relevance of this technology for new-building projects. Firstly, an evaluation of the waste heat resources available on board Mærsk containers fleet, and an estimation of the potential energy recovery by means of the ORC technology was performed...

  17. Leak detectors for organic Rankine cycle power plants: On-line and manual methods

    Science.gov (United States)

    Robertus, R. J.; Pool, K. H.; Kindle, C. H.; Sullivan, R. G.; Shannon, D. W.; Pierce, D. D.

    1984-10-01

    Two leak detector systems were designed, built, and tested at a binary-cycle (organic Rankine cycle) geothermal plant. One system is capable of detecting water in hydrocarbon streams down to 100 ppm liquid water ion liquid isobutane. The magnitude of the leak is estimated from the frequency at which solenoid-operated valve opens and closes. The second system can detect the presence of isobutane on water or brine streams down to 2 ppm liquid isobutane in liquid water or brine. The unit first cools the liquid stream if necessary then reduces the pressure in an expansion chamber so the hydrocarbon will vaporize. In brine streams flashed CO2 carries the hydrocarbon to a non-dispersive infrared analyzer (NDIR). The NDIR was modified to be highly selective for isobutane. One can estimate the size of a leak knowing the total gas-to-liquid ratio entering the leak detection system and the concentration of hydrocarbon in the gas phase.

  18. Uncertainty assessment of equations of state with application to an organic Rankine cycle

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Bell, Ian; O’Connell, John P.

    2017-01-01

    Evaluations of equations of state (EoS) should include uncertainty. This study presents a genericmethod to analyse EoS from a detailed uncertainty analysis of the mathematical form and the dataused to obtain EoS parameter values. The method is illustrated by comparison of Soave–Redlich–Kwong (SRK......) cubic EoS with perturbed-chain statistical associating fluid theory (PC-SAFT) EoS for anorganic Rankine cycle (ORC) for heat recovery to power fromthe exhaust gas of a marine diesel engineusing cyclopentane as working fluid. Uncertainties of the EoS input parameters including......Evaluations of equations of state (EoS) should include uncertainty. This study presents a genericmethod to analyse EoS from a detailed uncertainty analysis of the mathematical form and the dataused to obtain EoS parameter values. The method is illustrated by comparison of Soave–Redlich–Kwong (SRK...

  19. Rankine cycle condenser pressure control using an energy conversion device bypass valve

    Science.gov (United States)

    Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

    2014-04-01

    The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

  20. Control system to a Rankine cycle with a Tesla turbine using arduino

    International Nuclear Information System (INIS)

    Medeiros, Josenei G.; Guimaraes, Lamartine F.; Placco, Guilherme M.

    2013-01-01

    The thermal Rankine cycle is a thermodynamic cycle which converts heat in energy. This cycle occurs in steady state, in other words the cycle is a closed loop circuit with continuous feedback, which guarantees the reuse process one energy transformed in the various stages of the cycle. This cycle is used to drive a turbine type TESLA designed for the system. The objective of this work is to create the control and automation of this cycle using an micro-controlled system with Arduino that will hold the collection of sensors and the system will act to maintain the balance of the cycle causing it to behave continuously and with less interference from human operation for maintenance. Data will be collected and further processed, where it will display all the sensors and the situation of the actuators involved. Using Arduino system ensures the stability and reliability with a low cost of implementation

  1. Thermodynamic analysis of an integrated solid oxide fuel cell cycle with a rankine cycle

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of solid oxide fuel cells (SOFC) on the top of a steam turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydro-carbons. The pre-treated fuel enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a heat recovery steam generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67% are achieved which is considerably higher than the conventional combined cycles (CC). Both adiabatic steam reformer (ASR) and catalytic partial oxidation (CPO) fuel pre-reformer reactors are considered in this investigation.

  2. Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

    2016-01-01

    This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC...... modeloutput, and provides the 95%-confidence interval of the net power output with respect to the fluid property uncertainties. The methodology has been applied to a molecular design problem for an ORCusing a low-temperature heat source and consisted of the following four parts: 1) formulation...... of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output...

  3. Parametric optimization and comparative study of organic Rankine cycle (ORC) for low grade waste heat recovery

    International Nuclear Information System (INIS)

    Dai Yiping; Wang Jiangfeng; Gao Lin

    2009-01-01

    Organic Rankine cycles for low grade waste heat recovery are described with different working fluids. The effects of the thermodynamic parameters on the ORC performance are examined, and the thermodynamic parameters of the ORC for each working fluid are optimized with exergy efficiency as an objective function by means of the genetic algorithm. The optimum performance of cycles with different working fluids was compared and analyzed under the same waste heat condition. The results show that the cycles with organic working fluids are much better than the cycle with water in converting low grade waste heat to useful work. The cycle with R236EA has the highest exergy efficiency, and adding an internal heat exchanger into the ORC system could not improve the performance under the given waste heat condition. In addition, for the working fluids with non-positive saturation vapor curve slope, the cycle has the best performance property with saturated vapor at the turbine inlet

  4. Development of a computer code for a regenerative Rankine cycle analysis

    International Nuclear Information System (INIS)

    Wi, Myung Hwan; Kim, Seong O; Choi, Seok Ki; Kim, Jin Hwan

    2005-01-01

    A regenerative Rankine cycle can increase the thermal efficiency of a steam system without increasing the steam pressure and temperature. The regenerative process involves heating the feedwater on its return trip to the steam generator by extracting steam at various stages of the turbine and transferring the energy to the feedwater via a feedwater heater. Some real plants use more than five feedwater heaters to enhance the cycle efficiency. However, the optimum number of feedwater heaters required is determined by balancing the efficiency improvement against the capital investment for a given cycle. In the present study, the computer code, TAOPCS, for the thermodynamic analysis of a regenerative steam cycle was developed to optimally design and accurately analyze the behavior of the power conversion system of Korea Advance Liquid Metal Reactor (KALIMER). In order to understand the functions and the characteristics of the code, the main features of the TAPCS were described and the example results are presented in this paper

  5. Space reactor/organic Rankine conversion - A near-term state-of-the-art solution

    Science.gov (United States)

    Niggemann, R. E.; Lacey, D.

    The use of demonstrated reactor technology with organic Rankine cycle (ORC) power conversion can provide a low cost, minimal risk approach to reactor-powered electrical generation systems in the near term. Several reactor technologies, including zirconium hydride, EBR-II and LMFBR, have demonstrated long life and suitability for space application at the operating temperature required by an efficient ORC engine. While this approach would not replace the high temperature space reactor systems presently under development, it could be available in a nearer time frame at a low and predictable cost, allowing some missions requiring high power levels to be flown prior to the availability of advanced systems with lower specific mass. Although this system has relatively high efficiency, the heat rejection temperature is low, requiring a large radiator on the order of 3.4 sq m/kWe. Therefore, a deployable heat pipe radiator configuration will be required.

  6. Potassium Rankine cycle power conversion systems for lunar-Mars surface power

    International Nuclear Information System (INIS)

    Holcomb, R.S.

    1992-01-01

    The potassium Rankine cycle has good potential for application to nuclear power systems for surface power on the moon and Mars. A substantial effort on the development of the power conversion system was carried out in the 1960's which demonstrated successful operation of components made of stainless steel at moderate temperatures. This technology could be applied in the near term to produce a 360 kW(e) power system by coupling a stainless steel power conversion system to the SP-100 reactor. Improved performance could be realized in later systems by utilizing niobium or tantalum refractory metal alloys in the reactor and power conversion system. The design characteristics and estimated mass of power systems for each of three technology levels are presented in the paper

  7. Control system to a Rankine cycle with a Tesla turbine using arduino

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Josenei G., E-mail: joseneigodoi@yahoo.com.br [Faculdade de Tecnologia Sao Francisco (FATESF), Jacarei, SP (Brazil); Guimaraes, Lamartine F.; Placco, Guilherme M., E-mail: guimarae@ieav.cta.br, E-mail: placco@ieav.cta.br [Instituto de Estudos Avancados (ENU/IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Departamento de Energia Nuclear

    2013-07-01

    The thermal Rankine cycle is a thermodynamic cycle which converts heat in energy. This cycle occurs in steady state, in other words the cycle is a closed loop circuit with continuous feedback, which guarantees the reuse process one energy transformed in the various stages of the cycle. This cycle is used to drive a turbine type TESLA designed for the system. The objective of this work is to create the control and automation of this cycle using an micro-controlled system with Arduino that will hold the collection of sensors and the system will act to maintain the balance of the cycle causing it to behave continuously and with less interference from human operation for maintenance. Data will be collected and further processed, where it will display all the sensors and the situation of the actuators involved. Using Arduino system ensures the stability and reliability with a low cost of implementation.

  8. Performance analysis a of solar driven organic Rankine cycle using multi-component working fluids

    DEFF Research Database (Denmark)

    Baldasso, E.; Andreasen, J. G.; Modi, A.

    2015-01-01

    suitable control strategy and both the overall annual production and the average solar to electrical efficiency are estimated with an annual simulation. The results suggest that the introduction of binary working fluids enables to increase the solar system performance both in design and part-load operation....... cycle. The purpose of this paper is to optimize a low temperature organic Rankine cycle tailored for solar applications. The objective of the optimization is the maximization of the solar to electrical efficiency and the optimization parameters are the working fluid and the turbine inlet temperature...... and pressure. Both pure fluids and binary mixtures are considered as possible working fluids and thus one of the primary aims of the study is to evaluate whether the use of multi-component working fluids might lead to increased solar to electrical efficiencies. The considered configuration includes a solar...

  9. Uncertainty Assessment of Equations of State with Application to an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Bell, Ian; O’Connell, John P.

    2017-01-01

    Evaluations of equations of state (EoS) with application to process systems should include uncertainty analysis. A generic method is presented for determining such uncertainties from both the mathematical formand the data for obtaining EoS parameter values. The method is implemented for the Soave......–Redlich–Kwong (SRK), the Peng-Robinson (PR) cubic EoS, and the perturbed-chain statistical associating fluid theory (PCSAFT) EoS, as applied to an organic Rankine cycle (ORC) power system to recover heat from the exhaust gas of a marine diesel engine with cyclopentane as the working fluid. Uncertainties of the Eo......S input parameters, including their corresponding correlation structure, are quantified from the data using a bootstrap method. A Monte Carlo procedure propagates parameter input uncertainties onto the process output. Regressions have been made of the three cubic EoS parameters from both critical point...

  10. Thermal Stability of Hexamethyldisiloxane (MM for High-Temperature Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2016-03-01

    Full Text Available The design of efficient Organic Rankine Cycle (ORC units for the usage of industrial waste heat at high temperatures requires direct contact evaporators without intermediate thermal oil circuits. Therefore, the thermal stability of high-temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM is investigated in an electrically heated tube. Qualitative results concerning remarks on degradation products as well as quantitative results like the annual degradation rate are presented. It is shown that MM is stable up to a temperature of 300 °C with annual degradation rates of less than 3.5%. Furthermore, the break of a silicon–carbon bond can be a main chemical reaction that influences the thermal degradation. Finally, it is discussed how the results may impact the future design of ORC units.

  11. Thermodynamic analysis of an organic rankine cycle using a tubular solar cavity receiver

    International Nuclear Information System (INIS)

    Loni, R.; Kasaeian, A.B.; Mahian, O.; Sahin, A.Z.

    2016-01-01

    Highlights: • A non-regenerative Organic Rankine Cycle has been analyzed. • R113, R601, R11, R141b, Ethanol and Methanol were used as the working fluid. • A parabolic dish concentrator with a square prismatic cavity receiver was used. • Thermal efficiency, second law efficiency, and net power output were analyzed. - Abstract: In this study, a non-regenerative Organic Rankine Cycle (ORC) has been thermodynamically analyzed under superheated conditions, constant evaporator pressure of 2.5 MPa, and condenser temperature of 300 K. R113, R601, R11, R141b, Ethanol and Methanol were employed as the working fluid. A parabolic dish concentrator with a square prismatic tubular cavity receiver was used as the heat source of the ORC system. The effects of the tube diameter, the cavity depth, and the solar irradiation on the thermodynamic performance of the selected working fluid were investigated. Some thermodynamic parameters were analyzed in this study. These thermodynamic parameters included the thermal efficiency, second law efficiency, total irreversibility, availability ratio, mass flow rate, and net power output. The results showed that, among the selected working fluids, methanol had the highest thermal efficiency, net power output, second law efficiency, and availability ratio in the range of turbine inlet temperature (TIT) considered. On the other hand, methanol had the smallest total irreversibility in the same range of TIT. The results showed also that mass flow rate and consequently the net power output increased for higher solar irradiation, smaller tube diameter, and for the case of cubical cavity receiver (i.e. cavity depth h equal to the receiver aperture side length a).

  12. Analysis and optimization of the low-temperature solar organic Rankine cycle (ORC)

    International Nuclear Information System (INIS)

    Delgado-Torres, Agustin M.; Garcia-Rodriguez, Lourdes

    2010-01-01

    Solar thermal driven reverse osmosis desalination is a promising renewable energy-driven desalination technology. A joint use of the solar thermal powered organic Rankine cycle (ORC) and the desalination technology of less energy consumption, reverse osmosis (RO), makes this combination interesting in some scarce water resource scenarios. However, prior to any practical experience with any new process, a comprehensive and rigorous theoretical study must be done in order to assess the performance of the new technology or combination of existing technologies. The main objective of the present paper is the expansion of the theoretical analysis done by the authors in previous works to the case in which the thermal energy required by a solar ORC is supplied by means of stationary solar collectors. Twelve substances are considered as working fluids of the ORC and four different models of stationary solar collectors (flat plate collectors, compound parabolic collectors and evacuated tube collectors) are also taken into account. Operating conditions of the solar ORC that minimizes the aperture area needed per unit of mechanical power output of the solar cycle are determined for every working fluid and every solar collector. The former is done considering a direct vapour generation configuration of the solar cycle and also the configuration with water as heat transfer fluid flowing inside the solar collector. This work is part of the theoretical analysis of the solar thermal driven seawater and brackish water reverse osmosis desalination technology. Nevertheless, the supplied information can be also used for the assessment of different applications of the solar ORC. In that case, results presented in this paper can be useful in techno-economic analysis, selection of working fluids of the Rankine cycle, sizing of systems and assessment of solar power cycle configuration.

  13. Performance analyses of geothermal organic Rankine cycles with selected hydrocarbon working fluids

    International Nuclear Information System (INIS)

    Liu, Qiang; Duan, Yuanyuan; Yang, Zhen

    2013-01-01

    ORC (organic Rankine cycles) are promising systems for conversion of low temperature geothermal energy to electricity. The thermodynamic performance of the ORC with a wet cooling system is analyzed here using hydrocarbon working fluids driven by geothermal water from 100 °C to 150 °C and reinjection temperatures not less than 70 °C. The hydrocarbon working fluids are butane (R600), isobutane (R600a), pentane (R601), isopentane (R601a) and hexane. For each fluid, the ORC net power output first increases and then decreases with increasing turbine inlet temperature. The turbine inlet parameters are then optimized for the maximum power output. The ORC net power output increases as the condensation temperature decreases but the circulating pump power consumption increases especially for lower condensation temperatures at higher cooling water flow rates. The optimal condensation temperatures for the maximum plant power output are 29.45–29.75 °C for a cooling water inlet temperature of 20 °C and a pinch point temperature difference of 5 °C in the condenser. The maximum power is produced by an ORC using R600a at geothermal water inlet temperatures higher than 120 °C, followed by R245fa and R600 for reinjection temperatures not less than 70 °C. R600a also has the highest plant exergetic efficiency with the lowest turbine size factor. - Highlights: • ORC (organic Rankine cycles) using geothermal water from 100 to 150 °C and reinjection temperatures not less than 70 °C are analyzed. • Condensation temperatures optimized to maximize the plant power output. • An IHE (internal heat exchanger) gives higher plant power at low geothermal water temperatures and high reinjection temperatures. • ORC performance optimized considering the condensation and reinjection temperature. • R600a gives the best performance at the optimal turbine operating parameters

  14. Utilization of waste heat from GT-MHR for power generation in organic Rankine cycles

    International Nuclear Information System (INIS)

    Yari, Mortaza; Mahmoudi, S.M.S.

    2010-01-01

    The gas turbine-modular helium reactor (GT-MHR) is currently being developed by an international consortium. In this power plant, circulating helium that has to be compressed in a single or two successive stages cools the reactor core. For thermodynamic reasons, these compression stages require pre-cooling of the helium to about 26 deg. C through the use of intercooler and pre-cooler in which water is used to cool the helium. Considerable thermal energy (∼300 MWth) is thus dissipated in these components. This thermal energy is then rejected to a heat sink. For different designs, the temperature ranges of the helium in the intercooler and pre-cooler could be about 100 and 150 deg. C, respectively. These are ideal energy sources to be used in an organic Rankine cycles for power generation. This study examines the performance of a gas-cooled nuclear power plant with closed Brayton cycle (CBC) combined with two organic Rankine cycles (ORC). More attention was paid to the irreversibilities generated in the combined cycle. Individual models are developed for each component through applications of the first and second laws of thermodynamics. The effects of the turbine inlet temperature, compressor pressure ratio, evaporator temperature and temperature difference in the evaporator on the first- and second-law efficiencies and on the exergy destruction rate of the combined cycle were studied. Finally the combined cycle was optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on identical operating conditions, a comparison between the GT-MHR/ORC and a simple GT-MHR cycle is also made. It was found that both the first- and second-law efficiencies of GT-MHR/ORC cycle are about 3%-points higher than that of the simple GT-MHR cycle. Also, the exergy destruction rate for GT-MHR/ORC cycle is about 5% lower than that of the GT-MHR cycle.

  15. Exergy analysis of parabolic trough solar collectors integrated with combined steam and organic Rankine cycles

    International Nuclear Information System (INIS)

    Al-Sulaiman, Fahad A.

    2014-01-01

    Highlights: • As the solar irradiation increases, the exergetic efficiency increases. • The R134a combined cycle has best exergetic performance, 26%. • The R600a combined cycle has the lowest exergetic efficiency, 20%. • The main source of exergy destruction is the solar collector. • There is an exergetic improvement potential of 75% in the systems considered. - Abstract: In this paper, detailed exergy analysis of selected thermal power systems driven by parabolic trough solar collectors (PTSCs) is presented. The power is produced using either a steam Rankine cycle (SRC) or a combined cycle, in which the SRC is the topping cycle and an organic Rankine cycle (ORC) is the bottoming cycle. Seven refrigerants for the ORC were examined: R134a, R152a, R290, R407c, R600, R600a, and ammonia. Key exergetic parameters were examined: exergetic efficiency, exergy destruction rate, fuel depletion ratio, irreversibility ratio, and improvement potential. For all the cases considered it was revealed that as the solar irradiation increases, the exergetic efficiency increases. Among the combined cycles examined, the R134a combined cycle demonstrates the best exergetic performance with a maximum exergetic efficiency of 26% followed by the R152a combined cycle with an exergetic efficiency of 25%. Alternatively, the R600a combined cycle has the lowest exergetic efficiency, 20–21%. This study reveals that the main source of exergy destruction is the solar collector where more than 50% of inlet exergy is destructed, or in other words more than 70% of the total destructed exergy. In addition, more than 13% of the inlet exergy is destructed in the evaporator which is equivalent to around 19% of the destructed exergy. Finally, this study reveals that there is an exergetic improvement potential of 75% in the systems considered

  16. Potential of organic Rankine cycle using zeotropic mixtures as working fluids for waste heat recovery

    International Nuclear Information System (INIS)

    Li, You-Rong; Du, Mei-Tang; Wu, Chun-Mei; Wu, Shuang-Ying; Liu, Chao

    2014-01-01

    The performance of the ORC (organic Rankine cycle) systems using zeotropic mixtures as working fluids for recovering waste heat of flue gas from industrial boiler is examined on the basis of thermodynamics and thermo-economics under different operating conditions. In order to explore the potential of the mixtures as the working fluids in the ORC, the effects of various mixtures with different components and composition proportions on the system performance have been analyzed. The results show that the compositions of the mixtures have an important effect on the ORC system performance, which is associated with the temperature glide during the phase change of mixtures. From the point of thermodynamics, the performance of the ORC system is not always improved by employing the mixtures as the working fluids. The merit of the mixtures is related to the restrictive conditions of the ORC, different operating conditions results in different conclusions. At a fixed pinch point temperature difference, the small mean heat transfer temperature difference in heat exchangers will lead to a larger heat transfer area and the larger total cost of the ORC system. Compared with the ORC with pure working fluids, the ORC with the mixtures presents a poor economical performance. - Highlights: • Organic Rankine cycle system with the mixture working fluids for recovering waste heat is analyzed. • The performance of the mixture-fluid ORC is related to temperature glide in phase change of mixture working fluids. • The relative merit of the mixture working fluids depends on the restrictive operation conditions of the ORC. • The ORC with mixture working fluid presents a poor economical performance compared with the pure working fluid case

  17. Pre-treatment ASPECTS-DWI score has a relation with functional outcome at 3 months following intravenous rt-PA therapy

    International Nuclear Information System (INIS)

    Nezu, Tomohisa; Koga, Masatoshi; Naganuma, Masaki

    2009-01-01

    The clinical importance of early ischemic changes (EIC) on diffusion-weighted imaging (DWI) before recombinant tissue-plasminogen activator (rt-PA) thrombolysis has not been elucidated well. The present study aimed evaluating whether Alberta Stroke Programme Early CT Score (ASPECTS)-DWI before rt-PA therapy could predict chronic independent outcome. Consecutive stroke patients treated with rt-PA from October 2005 through July 2008 were registered from 10 major stroke centers located without regional imbalance in Japan. Before rt-PA IV infusion, we assessed EIC on DWI by using ASPECTS-DWI (11 points). Independent outcome was defined by modified Rankin Scale score (mRS) 0-2 at 3 months after stroke onset. A total of 420 patients (280 men, 71±11 years in age) were studied, and 221 (52.6%) of them were independent (mRS 0-2) at 3 months. The independent patients were younger, had less hypertension and atrial fibrillation, lower baseline National Institutes of Health Stroke Scale (NIHSS) score, higher ASPECTS-DWI, less internal carotid artery occlusion than dependent patients (mRS 3-6, P<0.05 for all). The optimal cutoff score of ASPECTS-DWI to predict independent outcome was ≥7 with a sensitivity of 92% and specificity of 31%, and the area under the receiver-operating characteristic curve was 0.622. After multivariate logistic regression analysis, ASPECTS-DWI ≥7 was independently predictive of an independent outcome at 3 months (odds ratio (OR) 2.78, 95% confidence interval (CI) 1.45-5.49). ASPECTS-DWI before rt-PA therapy is useful to predict patients' chronic functional outcome. (author)

  18. Clinical and radiologic features and their relationships with neurofunctional scores in patients with acute cerebellar infarct

    Directory of Open Access Journals (Sweden)

    Hasan Huseyin Kozak

    2016-01-01

    Full Text Available Background: Cerebellar infarct is a rare condition with very nonspecific clinical features. The aim of this study was to assess the full spectrum of the clinical characteristics, neuroimaging findings and neurofunctional analyses of cerebellar infarction, and the relationship between them. Materials and Methods: Data were collected from 59 patients admitted to our department during an 8-year period. We retrospectively analyzed the relationship between demographic characteristics, clinical symptomatology, etiological factors, functional condition, vascular distribution, frequency of subcortical white matter lesions (WMLs, and concomitant lesion outside the cerebellum in patients with acute cerebellar infarct (ACI at time of admission. Results: The mean age in our series was 65.2 years, with most being male (57.6%. The posterior inferior cerebellar (PICA artery was the most commonly affected territory at 62.7%. There was concomitant lesion outside the cerebellum in 45.7%. The main etiology in PICA was cardioembolism. While mean National Institutes of Health Stroke Scale on admission was 2.08 ± 1.67 in study group, modified Rankin Scale (mRS on admission was detected to be mRS1 (n: 44, 74.5% and mRS2 (n: 12, 20.3% most frequently. Fourteen (35% patients were detected to be in Fazekas stage 0; 11 (27.5% patients in Fazekas stage 1; 6 (15% patients in Fazekas stage 2; and 9 (22.5% patients in Fazekas stage 3. Conclusion: Cerebellar infarct is very heterogeneous. The other cerebral area infarcts which accompany ACI negatively affect neurologic functional scores. Although it is difficult to detect the relationship between WMLs and neurologic functional severity, timely detection of risk factors and their modulation may be associated with prevention and treatability of WMLs, and this may be one of the important points for prevention of stroke-related disability.

  19. An experimental analysis of flow boiling and pressure drop in a brazed plate heat exchanger for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Desideri, Adriano; Zhang, Ji; Kærn, Martin Ryhl

    2017-01-01

    Organic Rankine cycle power systems for low quality waste heat recovery applications can play a major role in achieving targets of increasing industrial processes efficiency and thus reducing the emissions of greenhouse gases. Low capacity organic Rankine cycle systems are equipped with brazed...... and pressure drop during vaporization at typical temperatures for low quality waste heat recovery organic Rankine cycle systems are presented for the working fluids HFC-245fa and HFO-1233zd. The experiments were carried out at saturation temperatures of 100°C, 115°C and 130°C and inlet and outlet qualities...

  20. Association Between Change in Body Mass Index, Unified Parkinson's Disease Rating Scale Scores, and Survival Among Persons With Parkinson Disease: Secondary Analysis of Longitudinal Data From NINDS Exploratory Trials in Parkinson Disease Long-term Study 1.

    Science.gov (United States)

    Wills, Anne-Marie A; Pérez, Adriana; Wang, Jue; Su, Xiao; Morgan, John; Rajan, Suja S; Leehey, Maureen A; Pontone, Gregory M; Chou, Kelvin L; Umeh, Chizoba; Mari, Zoltan; Boyd, James

    2016-03-01

    Greater body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) is associated with improved survival among persons with Huntington disease or amyotrophic lateral sclerosis. Weight loss is common among persons with Parkinson disease (PD) and is associated with worse quality of life. To explore the association between change in BMI, Unified Parkinson's Disease Rating Scale (UPDRS) motor and total scores, and survival among persons with PD and to test whether there is a positive association between BMI at randomization and survival. Secondary analysis (from May 27, 2014, to October 13, 2015) of longitudinal data (3-6 years) from 1673 participants who started the National Institute of Neurological Disorders and Stroke Exploratory Trials in PD Long-term Study-1 (NET-PD LS-1). This was a double-blind randomized placebo-controlled clinical trial of creatine monohydrate (10 g/d) that was performed at 45 sites throughout the United States and Canada. Participants with early (within 5 years of diagnosis) and treated (receiving dopaminergic therapy) PD were enrolled from March 2007 to May 2010 and followed up until September 2013. Change across time in motor UPDRS score, change across time in total UPDRS score, and time to death. Generalized linear mixed models were used to estimate the effect of BMI on the change in motor and total UPDRS scores after controlling for covariates. Survival was analyzed using Cox proportional hazards models of time to death. A participant's BMI was measured at randomization, and BMI trajectory groups were classified according to whether participants experienced weight loss ("decreasing BMI"), weight stability ("stable BMI"), or weight gain ("increasing BMI") during the study. Of the 1673 participants (mean [SD] age, 61.7 [9.6] years; 1074 [64.2%] were male), 158 (9.4%) experienced weight loss (decreasing BMI), whereas 233 (13.9%) experienced weight gain (increasing BMI). After adjusting for covariates, we

  1. Prediction of Large Vessel Occlusions in Acute Stroke: National Institute of Health Stroke Scale Is Hard to Beat.

    Science.gov (United States)

    Vanacker, Peter; Heldner, Mirjam R; Amiguet, Michael; Faouzi, Mohamed; Cras, Patrick; Ntaios, George; Arnold, Marcel; Mattle, Heinrich P; Gralla, Jan; Fischer, Urs; Michel, Patrik

    2016-06-01

    Endovascular treatment for acute ischemic stroke with a large vessel occlusion was recently shown to be effective. We aimed to develop a score capable of predicting large vessel occlusion eligible for endovascular treatment in the early hospital management. Retrospective, cohort study. Two tertiary, Swiss stroke centers. Consecutive acute ischemic stroke patients (1,645 patients; Acute STroke Registry and Analysis of Lausanne registry), who had CT angiography within 6 and 12 hours of symptom onset, were categorized according to the occlusion site. Demographic and clinical information was used in logistic regression analysis to derive predictors of large vessel occlusion (defined as intracranial carotid, basilar, and M1 segment of middle cerebral artery occlusions). Based on logistic regression coefficients, an integer score was created and validated internally and externally (848 patients; Bernese Stroke Registry). None. Large vessel occlusions were present in 316 patients (21%) in the derivation and 566 (28%) in the external validation cohort. Five predictors added significantly to the score: National Institute of Health Stroke Scale at admission, hemineglect, female sex, atrial fibrillation, and no history of stroke and prestroke handicap (modified Rankin Scale score, < 2). Diagnostic accuracy in internal and external validation cohorts was excellent (area under the receiver operating characteristic curve, 0.84 both). The score performed slightly better than National Institute of Health Stroke Scale alone regarding prediction error (Wilcoxon signed rank test, p < 0.001) and regarding discriminatory power in derivation and pooled cohorts (area under the receiver operating characteristic curve, 0.81 vs 0.80; DeLong test, p = 0.02). Our score accurately predicts the presence of emergent large vessel occlusions, which are eligible for endovascular treatment. However, incorporation of additional demographic and historical information available on hospital arrival

  2. Allegheny County Walk Scores

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Walk Score measures the walkability of any address using a patented system developed by the Walk Score company. For each 2010 Census Tract centroid, Walk Score...

  3. Um novo escore para dependência a nicotina e uma nova escala de conforto do paciente durante o tratamento do tabagismo A new nicotine dependence score and a new scale assessing patient comfort during smoking cessation treatment

    Directory of Open Access Journals (Sweden)

    Jaqueline Scholz Issa

    2012-12-01

    Full Text Available O tabagismo é considerado a maior causa evitável de morbidade e mortalidade. O manuseio farmacológico da síndrome de abstinência de nicotina possibilita melhores taxas de cessação. Desenvolvemos um sistema de coleta de dados em nosso programa de assistência ao fumante, que inclui dois instrumentos novos: um escore para dependência de nicotina em fumantes de Smoking is considered the leading preventable cause of morbidity and mortality. The pharmacological management of nicotine withdrawal syndrome enables better cessation rates. In our smoking cessation program, we have developed a data collection system, which includes two new instruments: a score that assesses nicotine dependence in smokers of < 10 cigarettes/day; and a patient comfort scale to be used during smoking cessation treatment. Here, we describe the two instruments, both of which are still undergoing validation.

  4. Performance Analysis of a Reciprocating Piston Expander and a Plate Type Exhaust Gas Recirculation Boiler in a Water-Based Rankine Cycle for Heat Recovery from a Heavy Duty Diesel Engine

    Directory of Open Access Journals (Sweden)

    Gunnar Latz

    2016-06-01

    Full Text Available The exhaust gas in an internal combustion engine provides favorable conditions for a waste-heat recovery (WHR system. The highest potential is achieved by the Rankine cycle as a heat recovery technology. There are only few experimental studies that investigate full-scale systems using water-based working fluids and their effects on the performance and operation of a Rankine cycle heat recovery system. This paper discusses experimental results and practical challenges with a WHR system when utilizing heat from the exhaust gas recirculation system of a truck engine. The results showed that the boiler’s pinch point necessitated trade-offs between maintaining adequate boiling pressure while achieving acceptable cooling of the EGR and superheating of the water. The expander used in the system had a geometric compression ratio of 21 together with a steam outlet timing that caused high re-compression. Inlet pressures of up to 30 bar were therefore required for a stable expander power output. Such high pressures increased the pump power, and reduced the EGR cooling in the boiler because of pinch-point effects. Simulations indicated that reducing the expander’s compression ratio from 21 to 13 would allow 30% lower steam supply pressures without adversely affecting the expander’s power output.

  5. A Generalised Assessment of Working Fluids and Radial Turbines for Non-Recuperated Subcritical Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Martin T. White

    2018-03-01

    Full Text Available The aim of this paper is to conduct a generalised assessment of both optimal working fluids and radial turbine designs for small-scale organic Rankine cycle (ORC systems across a range of heat-source temperatures. The former has been achieved by coupling a thermodynamic model of subcritical, non-recperated cycles with the Peng–Robinson equation of state, and optimising the working-fluid and cycle parameters for heat-source temperatures ranging between 80 ° C and 360 ° C . The critical temperature of the working fluid is found to be an important parameter governing working-fluid selection. Moreover, a linear correlation between heat-source temperature and the optimal critical temperature that achieves maximum power output has been found for heat-source temperatures below 300 ° C ( T cr = 0.830 T hi + 41.27 . This correlation has been validated against cycle calculations completed for nine predefined working fluids using both the Peng–Robinson equation of state and using the REFPROP program. Ultimately, this simple correlation can be used to identify working-fluid candidates for a specific heat-source temperature. In the second half of this paper, the effect of the heat-source temperature on the optimal design of a radial-inflow turbine rotor for a 25 kW subcritical ORC system has been studied. As the heat-source temperature increases, the optimal blade-loading coefficient increases, whilst the optimal flow coefficient reduces. Furthermore, passage losses are dominant in turbines intended for low-temperature applications. However, at higher heat-source temperatures, clearance losses become more dominant owing to the reduced blade heights. This information can be used to identify the most direct route to efficiency improvements in these machines. Finally, it is observed that the transition from a conventional converging stator to a converging-diverging stator occurs at heat-source temperatures of approximately 165 ° C , whilst radially

  6. Étude de la faisabilité des cycles sous-critiques et supercritiques de Rankine pour la valorisation de rejets thermiques

    OpenAIRE

    Le , Van Long

    2014-01-01

    This thesis concerns the feasibility study of subcritical and supercritical organic Rankine cycles for industrial waste heat recovery at relatively low temperature. Initially, a state of the art of ORCs (Organic Rankine Cycles) and their working fluids has been achieved. We conducted a preliminary comparison of several configurations from the scientific literature. In a second step, methods of energy and exergy analysis were applied to evaluate and optimize the performance of the ORCs. Indeed...

  7. Étude de la faisabilité des cycles sous-critiques et supercritiques de Rankine pour la valorisation de rejets thermiques

    OpenAIRE

    Le , Van Long

    2014-01-01

    This thesis concerns the feasibility study of subcritical and supercritical organic Rankine cycles for industrial waste heat recovery at relatively low temperature.Initially, a state of the art of ORCs (Organic Rankine Cycles) and their working fluids has been achieved. We conducted a preliminary comparison of several configurations from the scientific literature.In a second step, methods of energy and exergy analysis were applied to evaluate and optimize the performance of the ORCs. Indeed, ...

  8. Optimization of Cycle and Expander Design of an Organic Rankine Cycle Unit using Multi-Component Working Fluids

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Pierobon, Leonardo

    2016-01-01

    Organic Rankine cycle (ORC) power systems represent at-tractive solutions for power conversion from low temperatureheat sources, and the use of these power systems is gaining increasing attention in the marine industry. This paper proposesthe combined optimal design of cycle and expander...... for an organic Rankine cycle unit utilizing waste heat from low temperature heat sources. The study addresses a case where the minimum temperature of the heat source is constrained and a case where no constraint is imposed. The former case is the wasteheat recovery from jacket cooling water of a marine diesel...... engine onboard a large ship, and the latter is representative of a low-temperature geothermal, solar or waste heat recovery application. Multi-component working fluids are investigated, as they allow improving the match between the temperature pro-files in the heat exchangers and, consequently, reducing...

  9. Evaluation of ejector performance for an organic Rankine cycle combined power and cooling system

    International Nuclear Information System (INIS)

    Zhang, Kun; Chen, Xue; Markides, Christos N.; Yang, Yong; Shen, Shengqiang

    2016-01-01

    Highlights: • The performance of an ejector in an Organic Rankine Cycle and ejector refrigeration cycle (EORC) was evaluated. • The achieved entrainment ratio and COP of an EORC system is affected significantly by the evaporator conditions (such as temperature, pressure and flow rate). • An optimum distance of 6 mm nozzle position was found that ensures a maximum entrainment ratio, the best efficiency and lowest loss in the ejector. • A reduced total pressure loss between the nozzle inlet and exit leads to a lower energy loss, a higher entrainment ratio and better overall ejector performance. - Abstract: Power-generation systems based on organic Rankine cycles (ORCs) are well suited and increasingly employed in the conversion of thermal energy from low temperature heat sources to power. These systems can be driven by waste heat, for example from various industrial processes, as well as solar or geothermal energy. A useful extension of such systems involves a combined ORC and ejector-refrigeration cycle (EORC) that is capable, at low cost and complexity, of producing useful power while having a simultaneous capacity for cooling that is highly desirable in many applications. A significant thermodynamic loss in such a combined energy system takes place in the ejector due to unavoidable losses caused by irreversible mixing in this component. This paper focuses on the flow and transport processes in an ejector, in order to understand and quantify the underlying reasons for these losses, as well as their sensitivity to important design parameters and operational variables. Specifically, the study considers, beyond variations to the geometric design of the ejector, also the role of changing the external conditions across this component and how these affect its performance; this is not only important in helping develop ejector designs in the first instance, but also in evaluating how the performance may shift (in fact, deteriorate) quantitatively when the device

  10. An improved CO_2-based transcritical Rankine cycle (CTRC) used for engine waste heat recovery

    International Nuclear Information System (INIS)

    Shu, Gequn; Shi, Lingfeng; Tian, Hua; Li, Xiaoya; Huang, Guangdai; Chang, Liwen

    2016-01-01

    Highlights: • Propose an improved CTRC system (PR-CTRC) for engine waste heat recovery. • The PR-CTRC achieves a significant increase in thermodynamic performance. • The PR-CTRC possesses a strong coupling capability for high and low grade waste heat. • The PR-CTRC uses smaller turbine design parameters than ORC systems. • Total cooling load analysis of combined engine and recovery system was conducted. - Abstract: CO_2-based transcritical Rankine cycle (CTRC) is a promising technology for the waste heat recovery of an engine considering its safety and environment friendly characteristics, which also matchs the high temperature of the exhaust gas and satisfies the miniaturization demand of recovery systems. But the traditional CTRC system with a basic configuration (B-CTRC) has a poor thermodynamic performance. This paper introduces an improved CTRC system containing both a preheater and regenerator (PR-CTRC), for recovering waste heat in exhaust gas and engine coolant of an engine, and compares its performance with that of the B-CTRC system and also with that of the traditional excellent Organic Rankine Cycle (ORC) systems using R123 as a working fluid. The utilization rate of waste heat, total cooling load, net power output, thermal efficiency, exergy loss, exergy efficiency and component size have been investigated. Results show that, the net power output of the PR-CTRC could reach up to 9.0 kW for a 43.8 kW engine, which increases by 150% compared with that of the B-CTRC (3.6 kW). The PR-CTRC also improves the thermal efficiency and exergy efficiency of the B-CTRC, with increases of 184% and 227%, respectively. Compared with the ORC system, the PR-CTRC shows the significant advantage of highly recycling the exhaust gas and engine coolant simultaneously due to the special property of supercritical CO_2’s specific heat capacity. The supercritical property of CO_2 also generates a better heat transfer and flowing performances. Meanwhile, the PR

  11. Model of the expansion process for R245fa in an Organic Rankine Cycle (ORC)

    International Nuclear Information System (INIS)

    Luján, J.M.; Serrano, J.R.; Dolz, V.; Sánchez, J.

    2012-01-01

    An Organic Rankine Cycle (ORC) is considered as one of the most environmental-friendly ways to convert different kinds of low temperature energies, i.e. solar, geothermal, biomass and thermal energy of exhaust gases into electrical energy. Two important facts about the ORC must be considered: An organic fluid is selected as the working fluid and a high expansion ratio is usually presented in the machinery due to thermodynamic and efficiency factors. In the past, the pre-design of turbomachinery has been based on the usage of ideal fluid laws, but the real gas effects have a significant influence in the ORC working condition, due to its proximity to the saturation vapor line. In this article, the Equations of State (EoS) (Ideal gas, Redlich-Kwong-Soave and Peng–Robinson) have been evaluated in a typical ORC expansion in order to observe the inaccuracies of the ideal gas model with different thermodynamic variables. Finally an isothermal process followed by an isochoric process is proposed to reproduce the thermodynamic process of the organic fluid expansion by means of simpler equations. In the last point of this paper, several examples of this expansion process have been calculated, in order to analyze the proposed methodologies. It has been concluded that in typical expansion process of ORC (2.5 MPa-0.1 MPa and 1.6MPa-0.1 MPa), the PR and RKS equations show deviations between 6% and 8% in specific energy. These deviations are very low compared with the ideal gas equation whose deviations are above 100%. - Highlights: ► Evaluate the ideal gas behaviour of R245fa in typical working conditions of an Organic Rankine Cycle (ORC). ► Compare the ideal behaviour with other simple equations of state for real gas. ► Decide which equation of state has the highest precision in typical working conditions of an ORC. ► Derive the most important thermodynamic variables in each equation of state and decide the most accurate equation. ► Evaluate the speci c output

  12. Performance analysis of solar parabolic trough collectors driven combined supercritical CO2 and organic Rankine cycle

    Directory of Open Access Journals (Sweden)

    Harwinder Singh

    2018-06-01

    Full Text Available In this paper, attempts have been made on the detailed energy and exergy analysis of solar parabolic trough collectors (SPTCs driven combined power plant. The combination of supercritical CO2 (SCO2 cycle and organic Rankine cycle (ORC integrated with SPTCs has been used to produce power, in which SCO2 cycle and ORC are arranged as a topping and bottoming cycle. Five organic working fluids like R134a, R1234yf, R407c, R1234ze, and R245fa were selected for a low temperature bottoming ORC. Five key exergetic parameters such as exergetic efficiency, exergy destruction rate, fuel depletion ratio, irreversibility ratio, and improvement potential were also examined. It was revealed that exergetic and thermal efficiency of all the combined cycles enhances as the direct normal irradiance increases from 0.5 kW/m2 to 0.95 kW/m2. As can be seen, R407c combined cycle has the maximum exergetic as well as thermal efficiency which is around 78.07% at 0.95 kW/m2 and 43.49% at 0.95 kW/m2, respectively. Alternatively, the R134a and R245fa combined cycle yields less promising results with the marginal difference in their performance. As inferred from the study that SCO2 turbine and evaporator has a certain amount of exergy destruction which is around 9.72% and 8.54% of the inlet exergy, and almost 38.10% of the total exergy destruction in case of R407c combined cycle. Moreover, the maximum amount of exergy destructed by the solar collector field which is more than 25% of the solar inlet exergy and around 54% of the total destructed exergy. Finally, this study concludes that R407c combined cycle has a minimum fuel depletion ratio of 0.2583 for a solar collector and possess the highest power output of 3740 kW. Keywords: Supercritical CO2cycle, Organic Rankine cycle, Exergetic performance, SPTCs, Organic fluids

  13. Thermodynamic analysis of an Organic Rankine Cycle (ORC) based on industrial data

    International Nuclear Information System (INIS)

    Tumen Ozdil, N. Filiz; Segmen, M. Rıdvan; Tantekin, Atakan

    2015-01-01

    In this study, thermodynamic analysis of an Organic Rankine Cycle (ORC) is presented in a local power plant that is located southern of Turkey. The system that is analyzed includes an evaporator, a turbine, a condenser, a pump and a generator as components. System components are analyzed separately using actual plant data and performance cycle. The relationship between pinch point and exergy efficiency is observed. As the pinch point temperature decreases, the exergy efficiency increases due to low exergy destruction rate. The energy and exergy efficiencies of the ORC are calculated as 9.96% and 47.22%, respectively for saturated liquid form which is the real condition. In order to show the effect of the water phase of the evaporator inlet, exergy destruction and exergy efficiencies of components and overall system are calculated for different water phases. The exergy efficiency of the ORC is calculated as 41.04% for water mixture form which has quality 0.3. On the other hand, it is found as 40.29% for water mixture form which has quality 0.7. Lastly, it is calculated as 39.95% for saturated vapor form. Moreover, exergy destruction rates of the system are 520.01 kW for saturated liquid form, 598.39 kW for water mixture form which has quality 0.3, 609.5 kW for water mixture form which has quality 0.7 and 614.63 kW for saturated vapor form. The analyses show that evaporator has important effect on the system efficiency in terms of exergy rate. The evaporator is investigated particularly in order to improve the performance of the overall system. - Highlights: • Energy and exergy analysis of an Organic Rankine Cycle (ORC). • The main reasons of the irreversibility in the ORC. • Determination of exergy efficiency for the different water phases in the evaporator inlet. • Determination of the effect of the ambient temperature on ORC efficiency.

  14. Organic Rankine cycle saves energy and reduces gas emissions for cement production

    International Nuclear Information System (INIS)

    Wang, Huarong; Xu, Jinliang; Yang, Xufei; Miao, Zheng; Yu, Chao

    2015-01-01

    We investigated ORCs (organic Rankine cycles) integrated with typical China cement production line. The dry air at the kiln cooler outlet with the temperature of 220 °C was the waste heat. The fluids of hexane, isohexane, R601, R123 and R245fa were selected for ORCs based on the critical temperature criterion. The developed ORC verified the thermodynamics analysis. The NPV (net present value) and PBP (payback period) methods were applied to evaluate the economic performance. The LCA (life cycle assessment) was applied to evaluate the environment impacts. ORCs could generate 67,85,540–81,21,650 kWh electricity per year, equivalent to save 2035–2436 tons standard coal and reduce 7743–9268 tons CO 2 emission, for a 4000 t/d cement production line. ORCs reduced gas emissions of CO 2 by 0.62–0.74%, SO 2 by 3.83–4.59% and NO x by 1.36–1.63%. The PBP (payback period) was 2.74–3.42 years. The ORCs had the reduction ratios of EIL (environment impact load) by 1.49–1.83%, GWP (global warming potential) by 0.74–0.92%, AP (acidification potential) by 2.34–2.84%, EP (eutrophication potential) by 0.96–1.22% and HTP (human toxicity potential) by 2.38–2.89%. The ORC with R601 as the fluid had the best economic performance and significant gas emission reductions. ORCs had good economic performance and reduce the gas emissions. - Highlights: • Organic Rankine Cycles were integrated with the cement production line. • Five organic fluids were used as the working fluids for ORCs. • Thermal, economic and gas emission performances were analyzed. • R601 was the best fluid for ORC with the heat source temperature of 220 °C. • ORCs had good economic and gas emission reduction performances

  15. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A: Turbine Model

    Directory of Open Access Journals (Sweden)

    Andrea Meroni

    2016-04-01

    Full Text Available Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary turbine design model, the details of the validation and a sensitivity analysis on the main parameters, in order to minimize the number of decision variables in the subsequent turbine design optimization. Part B analyzes the application of the combined turbine and cycle designs on a selected case study, which was performed in order to show the advantages of the adopted methodology. Part A presents a one-dimensional turbine model and the results of the validation using two experimental test cases from literature. The first case is a subsonic turbine operated with air and investigated at the University of Hannover. The second case is a small, supersonic turbine operated with an organic fluid and investigated by Verneau. In the first case, the results of the turbine model are also compared to those obtained using computational fluid dynamics simulations. The results of the validation suggest that the model can predict values of efficiency within ± 1.3%-points, which is in agreement with the reliability of classic turbine loss models such as the Craig and Cox correlations used in the present study. Values similar to computational fluid dynamics simulations at the midspan were obtained in the first case of validation. Discrepancy below 12 % was obtained in the estimation of the flow velocities and turbine geometry. The values are considered to be within a

  16. Performance characterization of a power generation unit–organic Rankine cycle system based on the efficiencies of the system components

    International Nuclear Information System (INIS)

    Knizley, Alta; Mago, Pedro J.; Tobermann, James; Warren, Harrison R.

    2015-01-01

    Highlights: • Use of waste heat from a power generation unit to generate electricity is explored. • An organic Rankine cycle is used to recover the waste heat. • The system may lower cost, primary energy consumption, and carbon dioxide emission. • A parameter was established to show when the proposed system would provide savings. • The proposed system was evaluated in different locations in the US. - Abstract: This paper analyzes the potential of using the waste heat from a power generation unit to generate additional electricity using an organic Rankine cycle to reduce operational cost, primary energy consumption, and carbon dioxide emissions in different locations in the U.S. The power generation unit–organic Rankine cycle system is compared with a conventional system in terms of operational cost, primary energy consumption, and carbon dioxide emissions reduction. A parameter (R_m_i_n), which is based on system efficiencies, is established to determine when the proposed power generation unit–organic Rankine cycle system would potentially provide savings versus the conventional system in which electricity is purchased from the utility grid. The effect on the R_m_i_n parameter with variation of each system efficiency is also analyzed in this paper. Results indicated that savings in one parameter, such as primary energy consumption, did not imply savings in the other two parameters. Savings in the three parameters (operational cost, primary energy consumption, and carbon dioxide emissions) varied widely based on location due to prices of natural gas and electricity, source-to-site conversion factors, and carbon dioxide emissions conversion factors for electricity and natural gas. Variations in each system efficiency affected R_m_i_n, but varying the power generation unit efficiency had the most dramatic effect in the overall savings potential from the proposed system.

  17. Analisa Efisiensi Siklus Rankine Pada Sistem Pembangkit Tenaga Uap di PT. Pertamina (PERSERO) Refinery Unit IV Cilacap

    OpenAIRE

    Rahman, Fajril Ar

    2015-01-01

    Thermodynamic analysis was conducted to determine the thermal efficiency of the cycle Steam Power Plant. Rankine cycle is a thermodynamic basic principles that are commonly used to determine the performance and efficiency of a power plant. On Steam Generating System PT. Pertamina (Persero) RU IV Cilacap thermodynamic analysis has been conducted to determine the thermal efficiency and fuel use for different loading conditions. Thermodynamic analysis was done by determining the condition of the...

  18. Test results of an organic Rankine-cycle power module for a small community solar thermal power experiment

    Science.gov (United States)

    Clark, T. B.

    1985-01-01

    The organic Rankine-cycle (ORC) power conversion assembly was tested. Qualification testing of the electrical transport subsystem was also completed. Test objectives were to verify compatibility of all system elements with emphasis on control of the power conversion assembly, to evaluate the performance and efficiency of the components, and to validate operating procedures. After 34 hours of power generation under a wide range of conditions, the net module efficiency exceeded 18% after accounting for all parasitic losses.

  19. Part-Load Performance of aWet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    Directory of Open Access Journals (Sweden)

    Leonardo Pierobon

    2014-12-01

    Full Text Available Over the last years, much attention has been paid to the development of efficient and low-cost power systems for biomass-to-electricity conversion. This paper aims at investigating the design- and part-load performance of an innovative plant based on a wet indirectly fired gas turbine (WIFGT fueled by woodchips and an organic Rankine cycle (ORC turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model of the plant and to estimate its performance at different power outputs. The novel plant has a nominal power of 250 kW and a thermal efficiency of 43%. The major irreversibilities take place in the burner, recuperator, compressor and in the condenser. Toluene is the optimal working fluid for the organic Rankine engine. The part-load investigation indicates that the plant can operate at high efficiencies over a wide range of power outputs (50%–100%, with a peak thermal efficiency of 45% at around 80% load. While the ORC turbogenerator is responsible for the efficiency drop at low capacities, the off-design performance is governed by the efficiency characteristics of the compressor and turbine serving the gas turbine unit.

  20. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    Science.gov (United States)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-08-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives (η_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  1. Exergoeconomic assessment and parametric study of a Gas Turbine-Modular Helium Reactor combined with two Organic Rankine Cycles

    International Nuclear Information System (INIS)

    Mohammadkhani, F.; Shokati, N.; Mahmoudi, S.M.S.; Yari, M.; Rosen, M.A.

    2014-01-01

    An exergoeconomic analysis is reported for a combined system with a net electrical output of 299 MW in which waste heat from a Gas Turbine-Modular Helium Reactor (GT-MHR) is utilized by two Organic Rankine Cycles (ORCs). A parametric study is also done to reveal the effects on the exergoeconomic performance of the combined system of such significant parameters as compressor pressure ratio, turbine inlet temperature, temperatures of evaporators, pinch point temperature difference in the evaporators and degree of superheat at the ORC (Organic Rankine Cycle) turbines inlet. Finally the combined cycle performance is optimized from the viewpoint of exergoeconomics. The results show that the precooler, the intercooler and the ORC condensers exhibit the worst exergoeconomic performance. For the overall system, the exergoeconomic factor, the capital cost rate and the exergy destruction cost rate are determined to be 37.95%, 6876 $/h and 11,242 $/h, respectively. Also, it is observed that the unit cost of electricity produced by the GT-MHR turbine increases with increasing GT-MHR turbine inlet temperature but decreases as the other above mentioned parameters increase. - Highlights: • An exergoeconomic analysis is performed for the GT-MHR/ORC (Organic Rankine Cycle) combined cycle. • The effects of decision parameters on the exergoeconomic performance are studied. • The highest exergy destructions occur in the precooler, intercooler and condenser. • Superheating the working fluid at the ORC turbine inlet is not necessary. • Thermodynamic and exergoeconomic optimal conditions differ from each other

  2. Oxidation of mine tailings from Rankin Inlet, Nunavut, at subzero temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Meldrum, J. L.; Jamieson, H. E.; Dyke, L. D.

    2001-10-01

    An experiment was undertaken to determine if encapsulation in permafrost of acid-generating sulphidic tailings from a Ni-Cu mine on the shores of Hudson Bay in Nunavut will maintain the tailings and their saline pore water in a chemically inert state. The experiment involved collection of tailings material and pore water samples three years after burial, followed by long-term thermal monitoring. Tailings were studied at temperatures between +30 degrees C and -10 degrees C. Oxygen consumption was measured directly to determine the effect of low temperatures on oxidation rate. Significant oxidation was observed at +30 degrees C, which was substantially reduced at lower temperatures. At -10 degrees C oxygen consumption was below the detection limit. The highest measured oxygen flux correlated with a temperature increase of one degree C, which is consistent with exothermic sulphide oxidation reactions. The experiment showed that freezing in Rankin Inlet is progressing and tailings will be ice-bonded approximately 15 years after burial. 30 refs., 3 tabs. 6 figs.

  3. Evaluation of Working Fluids for Organic Rankine Cycle Based on Exergy Analysis

    Science.gov (United States)

    Setiawan, D.; Subrata, I. D. M.; Purwanto, Y. A.; Tambunan, A. H.

    2018-05-01

    One of the crucial aspects to determine the performance of Organic Rankine Cycle (ORC) is the selection of appropriate working fluids. This paper describes the simulative performance of several organic fluid and water as working fluid of an ORC based on exergy analysis with a heat source from waste heat recovery. The simulation was conducted by using Engineering Equation Solver (EES). The effect of several parameters and thermodynamic properties of working fluid was analyzed, and part of them was used as variables for the simulation in order to determine their sensitivity to the exergy efficiency changes. The results of this study showed that water is not appropriate to be used as working fluid at temperature lower than 130 °C, because the expansion process falls in saturated area. It was also found that Benzene had the highest exergy efficiency, i.e. about 10.49%, among the dry type working fluid. The increasing turbine inlet temperature did not lead to the increase of exergy efficiency when using organic working fluids with critical temperature near heat source temperature. Meanwhile, exergy efficiency decreasing linearly with the increasing condenser inlet temperature. In addition, it was found that working fluid with high latent heat of vaporization and specific heat exert in high exergy efficiency.

  4. Preliminary design and off-design performance analysis of an Organic Rankine Cycle for geothermal sources

    International Nuclear Information System (INIS)

    Hu, Dongshuai; Li, Saili; Zheng, Ya; Wang, Jiangfeng; Dai, Yiping

    2015-01-01

    Highlights: • A method for preliminary design and performance prediction is established. • Preliminary data of radial inflow turbine and plate heat exchanger are obtained. • Off-design performance curves of critical components are researched. • Performance maps in sliding pressure operation are illustrated. - Abstract: Geothermal fluid of 90 °C and 10 kg/s can be exploited together with oil in Huabei Oilfield of China. Organic Rankine Cycle is regarded as a reasonable method to utilize these geothermal sources. This study conducts a detailed design and off-design performance analysis based on the preliminary design of turbines and heat exchangers. The radial inflow turbine and plate heat exchanger are selected in this paper. Sliding pressure operation is applied in the simulation and three parameters are considered: geothermal fluid mass flow rate, geothermal fluid temperature and condensing pressure. The results indicate that in all considered conditions the designed radial inflow turbine has smooth off-design performance and no choke or supersonic flow are found at the nozzle and rotor exit. The lager geothermal fluid mass flow rate, the higher geothermal fluid temperature and the lower condensing pressure contribute to the increase of cycle efficiency and net power. Performance maps are illustrated to make system meet different load requirements especially when the geothermal fluid temperature and condensing pressure deviate from the design condition. This model can be used to provide basic data for future detailed design, and predict off-design performance in the initial design phase

  5. Comparison of different iterative schemes for ISPH based on Rankine source solution

    Directory of Open Access Journals (Sweden)

    Xing Zheng

    2017-07-01

    Full Text Available Smoothed Particle Hydrodynamics (SPH method has a good adaptability for the simulation of free surface flow problems. There are two forms of SPH. One is weak compressible SPH and the other one is incompressible SPH (ISPH. Compared with the former one, ISPH method performs better in many cases. ISPH based on Rankine source solution can perform better than traditional ISPH, as it can use larger stepping length by avoiding the second order derivative in pressure Poisson equation. However, ISPH_R method needs to solve the sparse linear matrix for pressure Poisson equation, which is one of the most expensive parts during one time stepping calculation. Iterative methods are normally used for solving Poisson equation with large particle numbers. However, there are many iterative methods available and the question for using which one is still open. In this paper, three iterative methods, CGS, Bi-CGstab and GMRES are compared, which are suitable and typical for large unsymmetrical sparse matrix solutions. According to the numerical tests on different cases, still water test, dam breaking, violent tank sloshing, solitary wave slamming, the GMRES method is more efficient than CGS and Bi-CGstab for ISPH method.

  6. Organic Rankine Cycle Analysis: Finding the Best Way to Utilize Waste Heat

    Directory of Open Access Journals (Sweden)

    Nadim Chakroun

    2012-01-01

    Full Text Available An Organic Rankine Cycle (ORC is a type of power cyclethat uses organic substances such as hydrocarbons orrefrigerants as the working fluid. ORC technology is usedto generate electricity in waste heat recovery applications,because the available heat is not at a high enoughtemperature to operate with other types of cycles. Theoptimum amount of working fluid required for the cycle(i.e., optimum charge level was investigated. Three chargelevels (13, 15, and 18 lbm were tested, and their effect onefficiency and performance of the system was analyzed.The heat source for the fluid was waste steam from thePurdue Power Plant, which had an average temperatureof 120oC. Regular city tap water at a temperature of 15oCwas used as the heat sink. For each charge level, multipletests were performed by measuring the temperaturesand pressures at all state points in the cycle, in order tounderstand any overarching patterns within the data.An important parameter that was analyzed is the 2nd lawefficiency. This efficiency is a measure of the effectivenessof the energy utilization compared to that of an idealcase. The peak efficiency increased from 24% to 27% asthe charge in the system decreased. Therefore, movingforward, this research suggests that a lower charge levelin the system will increase efficiency. However, testingbelow 13 lbm might cause mechanical complications inthe equipment as there may not be enough fluid to flowaround; thus, a compromise had to be made.

  7. Wave resistance calculation method combining Green functions based on Rankine and Kelvin source

    Directory of Open Access Journals (Sweden)

    LI Jingyu

    2017-12-01

    Full Text Available [Ojectives] At present, the Boundary Element Method(BEM of wave-making resistance mostly uses a model in which the velocity distribution near the hull is solved first, and the pressure integral is then calculated using the Bernoulli equation. However,the process of this model of wave-making resistance is complex and has low accuracy.[Methods] To address this problem, the present paper deduces a compound method for the quick calculation of ship wave resistance using the Rankine source Green function to solve the hull surface's source density, and combining the Lagally theorem concerning source point force calculation based on the Kelvin source Green function so as to solve the wave resistance. A case for the Wigley model is given.[Results] The results show that in contrast to the thin ship method of the linear wave resistance theorem, this method has higher precision, and in contrast to the method which completely uses the Kelvin source Green function, this method has better computational efficiency.[Conclusions] In general, the algorithm in this paper provides a compromise between precision and efficiency in wave-making resistance calculation.

  8. Design and process integration of organic Rankine cycle utilizing biomass for power generation

    Science.gov (United States)

    Ependi, S.; Nur, T. B.

    2018-02-01

    Indonesia has high potential biomass energy sources from palm oil mill industry activities. The growing interest on Organic Rankine Cycle (ORC) application to produce electricity by utilizing biomass energy sources are increasingly due to its successfully used for generating electricity from rejected waste heat to the environment in industrial processes. In this study, the potential of the palm oil empty fruit bunch, and wood chip have been used as fuel for biomass to generate electricity based ORC with combustion processes. The heat from combustion burner was transfer by thermal oil heater to evaporate ORC working fluid in the evaporator unit. The Syltherm-XLT thermal oil was used as the heat carrier from combustion burner, while R245fa was used as the working fluid for ORC unit. Appropriate designs integration from biomass combustion unit to ORC unit have been analyzed and proposed to generate expander shaft-work. Moreover, the effect of recuperator on the total system efficiency has also been investigated. It was observed that the fuel consumption was increased when the ORC unit equipped recuperator operated until certain pressure and decreased when operated at high pressure.

  9. Operation of an organic Rankine cycle dependent on pumping flow rates and expander torques

    International Nuclear Information System (INIS)

    Yang, Xufei; Xu, Jinliang; Miao, Zheng; Zou, Jinghuang; Yu, Chao

    2015-01-01

    An ORC (organic Rankine cycle) was developed with R123 as the working fluid. The heat capacity is in ∼100 kW. The match between pump and expander is investigated. Lower pump frequencies (f 10 Hz) adapt low expander torques only, and cause unstable flow and pump cavitation for larger expander torques. Ultra-low expander torques generate sufficiently high vapor superheatings to decrease expander efficiencies. Ultra-high expander torques achieve saturation vapor at the expander inlet, causing liquid droplets induced shock wave to worsen expander performance. An optimal range of expander torques exists to have better expander performance. A liquid subcooling of 20 °C is necessary to avoid pump cavitation. Expander powers and efficiencies show parabola shapes versus expander torques, or vapor superheatings at the expander inlet. The optimal vapor superheating is 13 °C. The cavitation mechanisms and measures to avoid cavitation are analyzed. This paper notes the overestimation of ORC performance by equilibrium thermodynamic analysis. Assumptions should be dependent on experiments. Future studies are suggested on organic fluid flow, heat transfer and energy conversion in various components. - Highlights: • The match between pump and expander is investigated. • A liquid subcooling of 20 °C is needed at pump inlet. • A vapor superheating of 13 °C is necessary at expander inlet. • Cavitation in pumps and expanders are analyzed. • The equilibrium thermodynamics overestimate ORC performances.

  10. Analysis of zeotropic mixtures used in high-temperature Organic Rankine cycle

    International Nuclear Information System (INIS)

    Dong, Bensi; Xu, Guoqiang; Cai, Yi; Li, Haiwang

    2014-01-01

    Highlights: • Using mixtures leads to an efficiency increase compared to pure fluids. • MM/MDM (0.4/0.6) produces optimal cycle efficiency. • Lower temperature gradients of heat source and sink give rise to higher cycle efficiency. • Condensation step shows more effect than evaporation step on cycle efficiency. - Abstract: The paper investigates the performance of high-temperature Organic Rankine cycle (ORC) with zeotropic mixtures as working fluid. A numerical model, which has been validated by comparing with the published data, is developed to predict the first law thermal efficiency of the cycle. The effects of mixture concentration, temperature gradient of the heat transfer fluid, pinch temperature difference, pressure ratio, and condensation pressure on the first law efficiency are presented firstly using a purposely designed program, and then the suitable conditions for the described ORC are suggested based on the results of the simulation. It is demonstrated that the use of zeotropic mixtures leads to an efficiency increase compared to pure fluids

  11. Numerical optimization of Combined Heat and Power Organic Rankine Cycles – Part A: Design optimization

    International Nuclear Information System (INIS)

    Martelli, Emanuele; Capra, Federico; Consonni, Stefano

    2015-01-01

    This two-part paper proposes an approach based on state-of-the-art numerical optimization methods for simultaneously determining the most profitable design and part-load operation of Combined Heat and Power Organic Rankine Cycles. Compared to the usual design practice, the important advantages of the proposed approach are (i) to consider the part-load performance of the ORC at the design stage, (ii) to optimize not only the cycle variables, but also the main turbine design variables (number of stages, stage loads, rotational speed). In this first part (Part A), the design model and the optimization algorithm are presented and tested on a real-world test case. PGS-COM, a recently proposed hybrid derivative-free algorithm, allows to efficiently tackle the challenging non-smooth black-box problem. - Highlights: • Algorithm for the simultaneous optimization Organic Rakine Cycle and turbine. • Thermodynamic and economic models of boiler, cycle, turbine are developed. • Non-smooth black-box optimization problem is successfully tackled with PGS-COM. • Test cases show that the algorithm returns optimal solutions within 4 min. • Toluene outperforms MDM (a siloxane) in terms of efficiency and costs.

  12. Organic Rankine kilowatt isotope power system. First annual summary report, August 1, 1975--August 1, 1976

    International Nuclear Information System (INIS)

    1976-01-01

    Sundstrand Energy Systems is developing a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980's. The KIPS is a plutonium oxide fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W(e) with a minimum of system changes. Research progress is reported on Phase I comprising: (1) flight system conceptual design and ground demonstration; (2) flight system design and ground qualification; and (3) flight system production, acceptance testing and delivery. The principal objectives of Phase I are to: (1) conceptually design the flight system, (2) based on the flight system concept, design and build the ground demonstration system (GDS), (3) conduct performance and endurance testing using electric heaters to simulate the radioisotope heat source, (4) identify and initiate long lead development efforts required to achieve the initial flight qualification hardware availability date of April 1981, and (5) finalize the flight concept design and prepare the program plan for the Phase II effort

  13. Performance analysis of low temperature heat source of organic Rankine cycle for geothermal application

    Science.gov (United States)

    Pintoro, A.; Ambarita, H.; Nur, T. B.; Napitupulu, F. H.

    2018-02-01

    Indonesia has a high potential energy resources from geothermal activities. Base on the report of Asian Development Bank and World Bank, the estimated of Indonesian hydrothermal geothermal resource considered to be the largest among the world. If it’s can be utilized to produce the electric power, it’s can contribute to increasing the electrification rates in Indonesia. In this study, an experimental studied of electric power generation, utilizing the Organic Rankine Cycle (ORC) system to convert the low level heat of hydrothermal as an energy source. The temperature of hydrothermal was modelled as hot water from water boiler which has a temperature range from 60 °C - 100 °C to heat up the organic working fluid of ORC system. The system can generated 1,337.7 watts of electricity when operated using R134A with hot water inlet temperature of 100 °C. Changing system working fluid to R245fa, the net power obtained increase to 1,908.9 watts with the same heat source condition. This study showed that the ORC system can be implemented to utilize low temperature heat source of hydrothermal in Indonesia.

  14. Computational modelling of an Organic Rankine Cycle (ORC waste heat recovery system for an aircraft engine

    Directory of Open Access Journals (Sweden)

    Saadon S.

    2018-01-01

    Full Text Available Escalating fuel prices and carbon dioxide emission are causing new interest in methods to increase the thrust force of an aircraft engine with limitation of fuel consumption. One viable means is the conversion of exhaust engine waste heat to a more useful form of energy or to be used in the aircraft environmental system. A one-dimensional analysis method has been proposed for the organic Rankine cycle (ORC waste heat recovery system for turbofan engine in this paper. The paper contains two main parts: validation of the numerical model and a performance prediction of turbofan engine integrated to an ORC system. The cycle is compared with industrial waste heat recovery system from Hangzhou Chinen Steam Turbine Power CO., Ltd. The results show that thrust specific fuel consumption (TSFC of the turbofan engine reach lowest value at 0.91 lbm/lbf.h for 7000 lbf of thrust force. When the system installation weight is applied, the system results in a 2.0% reduction in fuel burn. Hence implementation of ORC system for waste heat recovery to an aircraft engine can bring a great potential to the aviation industry.

  15. A new six stroke single cylinder diesel engine referring Rankine cycle

    International Nuclear Information System (INIS)

    Chen, Hao; Guo, Qi; Yang, Lu; Liu, Shenghua; Xie, Xuliang; Chen, Zhaoyang; Liu, Zengqiang

    2015-01-01

    Six stroke engine presented by Conklin and Szybist is an effective way to recover energy of exhaust gas by adding a partial exhaust stroke and steam expansion stroke. Characteristics of the engine are analyzed and its disadvantages are pointed out. A new six stroke diesel engine is presented here. It refers rankine cycle inside cylinder. Total exhaust gas is recompressed and at a relatively low back pressure in the fourth stroke water is injected to which maintains liquid phase until the piston moves to the TDC. At c′ 720 °CA (crank angle) the water becomes saturated. An ideal thermodynamics model of exhaust gas compression, water injection and expansion is constructed to investigate this modification. Properties at characteristic points are calculated to determine the increased indicated work. Results show that the work increases with the advance of water injection timing and the quality of water. The cycle is more efficient and the new engine has potential for saving energy. Moreover, it is forecasted that HC and PM emissions may reform with steam in reality and H 2 is produced which will react with NO X . - Highlights: • A new six stroke diesel engine is introduced and a new ideal cycle is constructed. • Increased indicated work of the cycle proves that the cycle is more efficient. • In reality steam may reform with HC and PM and produced H 2 may react with NO X emission. • The engine has the potential for energy saving and emission reducing

  16. Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

    Science.gov (United States)

    Moghimi, Mahdi; Khosravian, Mohammadreza

    2018-06-01

    In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

  17. Organic Rankine cycle – review and research directions in engine applications

    Directory of Open Access Journals (Sweden)

    Panesar Angad

    2017-01-01

    Full Text Available Waste heat to power conversion using Organic Rankine Cycles (ORC is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2 are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

  18. Exergoeconomic analysis of a solar-powered/fuel assisted Rankine cycle for power generation

    International Nuclear Information System (INIS)

    Cavalcanti, Eduardo J.C.; Motta, Henrique Pereira

    2015-01-01

    A Rankine System assisted for solar radiation and fuel combustion which produces 57 kW electrical power are evaluated from exergoeconomic point of view. The Parabolic trough collector efficiency has been performed to investigate its effect as heat source. The exergoeconomic parameters as the relative cost difference and the exergoeconomic factor for each component are evaluated. The analysis is based on the SPECO (Specific Exergy Costing) approach. The simulation of system on March, June, September and December 21st from 7 am to 4 pm for Natal/Brazil using real data was carried out. The results reveal the daily average values of collector efficiencies, ratio of the useful solar energy, electricity produced, the specific cost per exergy unit of the produced electricity and others heat rates. The system is advantageous for higher solar radiation. The outcome of the analysis can be useful in design, optimization of operating parameters and help to take decision of investment. - Highlights: • As the solar irradiation decreases, the electricity cost per exergy unit increases. • The cost rate is high at collector field due to higher purchase cost. • The system is advantageous when the solar radiation is high. • Further aspect as environmental impact is important

  19. Low-order models of a single-screw expander for organic Rankine cycle applications

    Science.gov (United States)

    Ziviani, D.; Desideri, A.; Lemort, V.; De Paepe, M.; van den Broek, M.

    2015-08-01

    Screw-type volumetric expanders have been demonstrated to be a suitable technology for organic Rankine cycle (ORC) systems because of higher overall effectiveness and good part-load behaviour over other positive displacement machines. An 11 kWe single-screw expander (SSE) adapted from an air compressor has been tested in an ORC test-rig operating with R245fa as working fluid. A total of 60 steady-steady points have been obtained at four different rotational speeds of the expander in the range between 2000 rpm and 3300 rpm. The maximum electrical power output and overall isentropic effectiveness measured were 7.3 kW and 51.9%, respectively. In this paper, a comparison between two low-order models is proposed in terms of accuracy of the predictions, the robustness of the model and the computational time. The first model is the Pacejka equation-based model and the second is a semi-empirical model derived from a well-known scroll expander model and modified to include the geometric aspects of a single screw expander. The models have been calibrated with the available steady-state measurement points by identifying the proper parameters.

  20. Optimization of low temperature solar thermal electric generation with Organic Rankine Cycle in different areas

    International Nuclear Information System (INIS)

    Jing, Li; Gang, Pei; Jie, Ji

    2010-01-01

    The presented low temperature solar thermal electric generation system mainly consists of compound parabolic concentrators (CPC) and the Organic Rankine Cycle (ORC) working with HCFC-123. A novel design is proposed to reduce heat transfer irreversibility between conduction oil and HCFC-123 in the heat exchangers while maintaining the stability of electricity output. Mathematical formulations are developed to study the heat transfer and energy conversion processes and the numerical simulation is carried out based on distributed parameters. Annual performances of the proposed system in different areas of Canberra, Singapore, Bombay, Lhasa, Sacramento and Berlin are simulated. The influences of the collector tilt angle adjustment, the connection between the heat exchangers and the CPC collectors, and the ORC evaporation temperature on the system performance are investigated. The results indicate that the three factors have a major impact on the annual electricity output and should be the key points of optimization. And the optimized system shows that: (1) The annual received direct irradiance can be significantly increased by two or three times optimal adjustments even when the CPC concentration ratio is smaller than 3.0. (2) Compared with the traditional single-stage collectors, two-stage collectors connected with the heat exchangers by two thermal oil cycles can improve the collector efficiency by 8.1-20.9% in the simultaneous processes of heat collection and power generation. (3) On the use of the market available collectors the optimal ORC evaporation temperatures in most of the simulated areas are around 120 C. (author)

  1. Organic Rankine Cycle recovering stage heat from MSF desalination distillate water

    International Nuclear Information System (INIS)

    Al-Weshahi, Mohammed A.; Anderson, Alexander; Tian, Guohong

    2014-01-01

    Highlights: • The ORC model is validated against measured performance of an existing ORC unit. • This ORC model highlights the importance of refrigerant choice (R245fa performs better than R134a for this specific application). • For heat recovery from desalination plant, ORC evaporator and cooling water temperatures significantly influence the performance. - Abstract: This investigation addresses the potential for heat recovery from Multi Stage Flash (MSF) desalination plant hot distillate water to power an Organic Rankine Cycle (ORC), comparing R134a and R245fa refrigerants as the working fluid. Using design characteristics of an existing ORC unit, the model was first validated against its measured output. The distillate hot water from MSF stages is utilised to provide heat to the ORC and performance is investigated for both working fluids and for the number of MSF stages for heat recovery. For the specific MSF plant investigated, the net produced ORC power is found the highest with extraction up to MSF powering stage 8, generating 359 kW when R245fa is used and 307 kW when R134a is used. Both refrigerants exhibit an increase of power output and decrease of energy efficiency as heat is recovered from more MSF stages. The influence of variation of the evaporator and cooling temperature on ORC performance is demonstrated to be significant for both refrigerants, with R245fa performing better in this specific application

  2. Investigation of the organic Rankine cycle (ORC) system and the radial-inflow turbine design

    International Nuclear Information System (INIS)

    Li, Yan; Ren, Xiao-dong

    2016-01-01

    Highlights: • The thermodynamic analysis of an ORC system is introduced. • A radial turbine design method has been proposed based on the real gas model. • A radial turbine with R123 is designed and numerically analyzed. - Abstract: Energy and environment issue set utilizing low-grade heat noticed. Organic Rankine Cycle (ORC) has been demonstrated to be a promising technology to recover waste heat. As a critical component of ORC system, the turbine selection has an enormous influence on the system performance. This paper carries out a study on the thermodynamic analysis of ORC system and the aerodynamic design of an organic radial turbine. The system performance is evaluated with various working fluids. The aerodynamic design of the organic radial-inflow turbine is focused due to the high molecule weight and the low sound speed of the organic working fluid. An aerodynamic and profile design system is developed. A radial-inflow turbine with R123 as the working fluid is designed and the numerical analysis is conducted. The simulation results indicate that the shock wave caused by the high expansion ratio in the nozzle is well controlled. Compared with the one-dimensional design results, the performance of the radial-inflow turbine in this paper reaches the design requirements.

  3. Reciprocating Expander for an Exhaust Heat Recovery Rankine Cycle for a Passenger Car Application

    Directory of Open Access Journals (Sweden)

    Osoko Shonda

    2012-06-01

    Full Text Available Nowadays, on average, two thirds of the fuel energy consumed by an engine is wasted through the exhaust gases and the cooling liquid. The recovery of this energy would enable a substantial reduction in fuel consumption. One solution is to integrate a heat recovery system based on a steam Rankine cycle. The key component in such a system is the expander, which has a strong impact on the system’s performance. A survey of different expander technologies leads us to select the reciprocating expander as the most promising one for an automotive application. This paper therefore proposes a steady-state semi-empirical model of the expander device developed under the Engineering Equation Solver (EES environment. The ambient and mechanical losses as well as internal leakage were taken into account by the model. By exploiting the expander manufacturer’s data, all the parameters of the expander model were identified. The model computes the mass flow rate, the power output delivered and the exhaust enthalpy of the steam. The maximum deviation between predictions and measurement data is 4.7%. A performance study of the expander is carried out and shows that the isentropic efficiency is quite high and increases with the expander rotary speed. The mechanical efficiency depends on mechanical losses which are quite high, approximately 90%. The volumetric efficiency was also evaluated.

  4. Experimental Investigation of the Performance of a Hermetic Screw-Expander Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Sung-Wei Hsu

    2014-09-01

    Full Text Available In this study, the authors experimentally investigate the performance of the organic Rankine cycle (ORC and screw expander under the influence of supply pressure and pressure ratio over the expander. Three tests were performed with expander pressure ratios of 2.4–3.5, 3.0–4.6, and 3.3–6.1, which cover the over-expansion and under-expansion operating modes. The test results show a maximum expander isentropic efficiency of 72.4% and a relative cycle efficiency of 10.5% at an evaporation temperature of 101 °C and condensation temperature of 45 °C. At a given pressure ratio over the expander, a higher supply pressure to the expander causes a higher expander isentropic efficiency and higher cycle efficiency in the over-expansion mode. However, in the under-expansion mode, the higher supply pressure results in a lower expander isentropic efficiency and adversely affects the cycle efficiency. The results also show that under the condition of operation at a given pressure ratio, a higher supply pressure yields a larger power output owing to the increased mass flow rate at the higher supply pressure. The study results demonstrate that a screw-expander ORC can be operated with a wide range of heat sources and heat sinks with satisfactory cycle efficiency.

  5. Performance analysis of an organic Rankine cycle with internal heat exchanger having zeotropic working fluid

    Directory of Open Access Journals (Sweden)

    Thoranis Deethayat

    2015-09-01

    Full Text Available In this study, performance of a 50 kW organic Rankine cycle (ORC with internal heat exchanger (IHE having R245fa/R152a zeotropic refrigerant with various compositions was investigated. The IHE could reduce heat rate at the ORC evaporator and better cycle efficiency could be obtained. The zeotropic mixture could reduce the irreversibilities during the heat exchanges at the ORC evaporator and the ORC condenser due to its gliding temperature; thus the cycle working temperatures came closer to the temperatures of the heat source and the heat sink. In this paper, effects of evaporating temperature, mass fraction of R152a and effectiveness of internal heat exchanger on the ORC performances for the first law and the second law of thermodynamics were considered. The simulated results showed that reduction of R245fa composition could reduce the irreversibilities at the evaporator and the condenser. The suitable composition of R245fa was around 80% mass fraction and below this the irreversibilities were nearly steady. Higher evaporating temperature and higher internal heat exchanger effectiveness also increased the first law and second law efficiencies. A set of correlations to estimate the first and the second law efficiencies with the mass fraction of R245fa, the internal heat exchanger effectiveness and the evaporating temperature were also developed.

  6. Energy analysis of a trigeneration plant based on solid oxide fuel cell and organic Rankine cycle

    International Nuclear Information System (INIS)

    Al-Sulaiman, F.A.; Dincer, I.; Hamdullahpur, F.

    2009-01-01

    In this paper, energy analysis of a trigeneration plant based on Solid Oxide Fuel cell (SOFC) and organic Rankine cycle (ORC) is carried out. The physical and thermodynamic elements of the plant include a SOFC, ORC, a heating process and a single-effect absorption chiller. The waste heat from the SOFC is used as an input heat to the ORC. In turn, the waste heat from the ORC is used to heat the inlet water, and to provide the heat needed for the single-effect absorption chiller. The results obtained from this study show that the highest cycle efficiency that can be attained under the proposed scheme is 48% and the highest SOFC efficiency is 43%. Furthermore, it is found that the highest net work rate is 435 kW and the highest SOFC-AC work rate is 337 kW. At a current density higher than 0.87 A/cm 2 , the SOFC and cycle efficiencies drop abruptly because of the sharp increase in the voltage losses of the SOFC. At a current density of 0.75 A/cm 2 , the highest SOFC efficiency of 41% is obtained at the inlet fuel cell temperature of 890 K. The change in the inlet pressure of the turbine has insignificant effect on the efficiencies of the ORC and overall cycle. The study shows the effect of both the current density and the inlet fuel cell temperature on the cell voltage and voltage loss. (author)

  7. Combined solar organic Rankine cycle with reverse osmosis desalination process: Energy, exergy, and cost evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Nafey, A.S.; Sharaf, M.A. [Department of Engineering Science, Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2010-11-15

    Organic Rankine cycles (ORC) have unique properties that are well suited to solar power generation. In this work design and performance calculations are performed using MatLab/SimuLink computational environment. The cycle consists of thermal solar collectors (Flat Plate Solar Collector (FPC), or Parabolic Trough Collector (PTC), or Compound Parabolic Concentrator (CPC)) for heat input, expansion turbine for work output, condenser unit for heat rejection, pump unit, and Reverse Osmosis (RO) unit. Reverse osmosis unit specifications used in this work is based on Sharm El-Shiekh RO desalination plant. Different working fluids such as: butane, isobutane, propane, R134a, R152a, R245ca, and R245fa are examined for FPC. R113, R123, hexane, and pentane are investigated for CPC. Dodecane, nonane, octane, and toluene are allocated for PTC. The proposed process units are modeled and show a good validity with literatures. Exergy and cost analysis are performed for saturation and superheated operating conditions. Exergy efficiency, total exergy destruction, thermal efficiency, and specific capital cost are evaluated for direct vapor generation (DVG) process. Toluene and Water achieved minimum results for total solar collector area, specific total cost and the rate of exergy destruction. (author)

  8. Evaluation of a solar-powered organic Rankine cycle using dry organic working fluids

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2015-12-01

    Full Text Available This paper presents a model to evaluate the performance of a solar-powered organic Rankine cycle (ORC. The system was evaluated in Jackson, MS, using five dry organic working fluids, R218, R227ea, R236ea, R236fa, and RC318. The purpose of this study is to investigate how hourly temperature change affects the electricity production and exergy destruction rates of the solar ORC, and to determine the effect of the working fluid on the proposed system. The system was also evaluated in Tucson, AZ, to investigate the effect of average hourly outdoor temperatures on its performance. The potential of the system to reduce primary energy consumption and carbon dioxide emissions is also investigated. A parametric analysis to determine how temperature and pressure of the organic working fluid, the solar collector area, and the turbine efficiency affect the electricity production is performed. Results show that the ORC produces the most electricity during the middle of the day, when the temperatures are the highest and when the solar collectors have the highest efficiency. Also, R-236ea is the working fluid that shows the best performance of the evaluated fluids. An economic analysis was performed to determine the capital cost available for the proposed system.

  9. Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Ratha Z. Mathkor

    2015-08-01

    Full Text Available This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC, an organic Rankine cycle (ORC, single-effect desalination (SED, and single effect LiBr-H2O absorption chiller (ACH was electrical power, distilled water, and refrigerant load. The electrical power was produced by the ORC which used cyclopentane as working fluid and Therminol VP-1 was specified as the heat transfer oil (HTO in the collectors with thermal storage. The absorption chiller and the desalination unit were utilize the waste heat exiting from the steam turbine in the ORC to provide the necessary cooling energy and drinking water respectively. The modelling, which includes an exergetic analysis, focuses on the performance of the solar tri-generation system. The simulation results of the tri-generation system and its subsystems were produced using IPSEpro software and were validated against experimental data which showed good agreement. The tri-generation system was able to produce about 194 Ton of refrigeration, and 234 t/day distilled water.

  10. Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

    Science.gov (United States)

    Moghimi, Mahdi; Khosravian, Mohammadreza

    2018-01-01

    In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

  11. Dynamic Simulation of an Organic Rankine Cycle—Detailed Model of a Kettle Boiler

    Directory of Open Access Journals (Sweden)

    Roberto Pili

    2017-04-01

    Full Text Available Organic Rankine Cycles (ORCs are nowadays a valuable technology to produce electricity from low and medium temperature heat sources, e.g., in geothermal, biomass and waste heat recovery applications. Dynamic simulations can help improve the flexibility and operation of such plants, and guarantee a better economic performance. In this work, a dynamic model for a multi-pass kettle evaporator of a geothermal ORC power plant has been developed and its dynamics have been validated against measured data. The model combines the finite volume approach on the tube side and a two-volume cavity on the shell side. To validate the dynamic model, a positive and a negative step function in heat source flow rate is applied. The simulation model performed well in both cases. The liquid level appeared the most challenging quantity to simulate. A better agreement in temperature was achieved by increasing the volume flow rate of the geothermal brine by 2% over the entire simulation. Measurement errors, discrepancies in working fluid and thermal brine properties and uncertainties in heat transfer correlations can account for this. In the future, the entire geothermal power plant will be simulated, and suggestions to improve its dynamics and control by means of simulations will be provided.

  12. Molecular Entropy, Thermal Efficiency, and Designing of Working Fluids for Organic Rankine Cycles

    Science.gov (United States)

    Wang, Jingtao; Zhang, Jin; Chen, Zhiyou

    2012-06-01

    A shortage of fossil energy sources boosts the utilization of renewable energy. Among numerous novel techniques, recovering energy from low-grade heat sources through power generation via organic Rankine cycles (ORCs) is one of the focuses. Properties of working fluids are crucial for the ORC's performance. Many studies have been done to select proper working fluids or to design new working fluids. However, no researcher has systematically investigated the relationship between molecular structures and thermal efficiencies of various working fluids for an ideal ORC. This paper has investigated the interrelations of molecular structures, molecular entropies, and thermal efficiencies of various working fluids for an ideal ORC. By calculating thermal efficiencies and molecular entropies, we find that the molecular entropy is the most appropriate thermophysical property of a working fluid to determine how much energy can be converted into work and how much cannot in a system. Generally speaking, working fluids with low entropies will generally have high thermal efficiency for an ideal ORC. Based on this understanding, the direct interrelations of molecular structures and entropies provide an explicit interrelation between molecular structures and thermal efficiencies, and thus provide an insightful direction for molecular design of novel working fluids for ORCs.

  13. Real-Time Optimization of Organic Rankine Cycle Systems by Extremum-Seeking Control

    Directory of Open Access Journals (Sweden)

    Andres Hernandez

    2016-05-01

    Full Text Available In this paper, the optimal operation of a stationary sub-critical 11 kW el organic Rankine cycle (ORC unit for waste heat recovery (WHR applications is investigated, both in terms of energy production and safety conditions. Simulation results of a validated dynamic model of the ORC power unit are used to derive a correlation for the evaporating temperature, which maximizes the power generation for a range of operating conditions. This idea is further extended using a perturbation-based extremum seeking (ES algorithm to identify online the optimal evaporating temperature. Regarding safety conditions, we propose the use of the extended prediction self-adaptive control (EPSAC approach to constrained model predictive control (MPC. Since it uses input/output models for prediction, it avoids the need for state estimators, making it a suitable tool for industrial applications. The performance of the proposed control strategy is compared to PID-like schemes. Results show that EPSAC-MPC is a more effective control strategy, as it allows a safer and more efficient operation of the ORC unit, as it can handle constraints in a natural way, operating close to the boundary conditions where power generation is maximized.

  14. Thermodynamic and heat transfer analysis of heat recovery from engine test cell by Organic Rankine Cycle

    Science.gov (United States)

    Shokati, Naser; Mohammadkhani, Farzad; Farrokhi, Navid; Ranjbar, Faramarz

    2014-12-01

    During manufacture of engines, evaluation of engine performance is essential. This is accomplished in test cells. During the test, a significant portion of heat energy released by the fuel is wasted. In this study, in order to recover these heat losses, Organic Rankine Cycle (ORC) is recommended. The study has been conducted assuming the diesel oil to be composed of a single hydrocarbon such as C12H26. The composition of exhaust gases (products of combustion) have been computed (and not determined experimentally) from the stoichiometric equation representing the combustion reaction. The test cell heat losses are recovered in three separate heat exchangers (preheater, evaporator and superheater). These heat exchangers are separately designed, and the whole system is analyzed from energy and exergy viewpoints. Finally, a parametric study is performed to investigate the effect of different variables on the system performance characteristics such as the ORC net power, heat exchangers effectiveness, the first law efficiency, exergy destruction and heat transfer surfaces. The results of the study show that by utilizing ORC, heat recovery equivalent to 8.85 % of the engine power is possible. The evaporator has the highest exergy destruction rate, while the pump has the lowest among the system components. Heat transfer surfaces are calculated to be 173.6, 58.7, and 11.87 m2 for the preheater, evaporator and superheater, respectively.

  15. Thermal analysis of a Phase Change Material for a Solar Organic Rankine Cycle

    Science.gov (United States)

    Iasiello, M.; Braimakis, K.; Andreozzi, A.; Karellas, S.

    2017-11-01

    Organic Rankine Cycle (ORC) is a promising technology for low temperature power generation, for example for the utilization of medium temperature solar energy. Since heat generated from solar source is variable throughout the day, the implementation of Thermal Energy Storage (TES) systems to guarantee the continuous operation of solar ORCs is a critical task, and Phase Change Materials (PCM) rely on latent heat to store large amounts of energy. In the present study, a thermal analysis of a PCM for a solar ORC is carried out. Three different types of PCMs are analyzed. The energy equation for the PCM is modeled by using the heat capacity method, and it is solved by employing a 1Dexplicit finite difference scheme. The solar source is modeled with a time-variable temperature boundary condition, with experimental data t