Advanteges of using Two-Switch Forward in Single-Stage Power Factor Corrected Power Supplies

DEFF Research Database (Denmark)

Petersen, Lars

2000-01-01

A single-Stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (Discontinues Conduction Mode). This will insure the intermediate DC-bus to be controlled only by means of circuit parameters and therefore...... power supply has been implemented. The measured efficiency and power factor are about 87% and 0.96 respectively....

Two-Stage Centrifugal Fan

Science.gov (United States)

Converse, David

2011-01-01

Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

Meta-analysis of Gaussian individual patient data: Two-stage or not two-stage?

Science.gov (United States)

Morris, Tim P; Fisher, David J; Kenward, Michael G; Carpenter, James R

2018-04-30

Quantitative evidence synthesis through meta-analysis is central to evidence-based medicine. For well-documented reasons, the meta-analysis of individual patient data is held in higher regard than aggregate data. With access to individual patient data, the analysis is not restricted to a "two-stage" approach (combining estimates and standard errors) but can estimate parameters of interest by fitting a single model to all of the data, a so-called "one-stage" analysis. There has been debate about the merits of one- and two-stage analysis. Arguments for one-stage analysis have typically noted that a wider range of models can be fitted and overall estimates may be more precise. The two-stage side has emphasised that the models that can be fitted in two stages are sufficient to answer the relevant questions, with less scope for mistakes because there are fewer modelling choices to be made in the two-stage approach. For Gaussian data, we consider the statistical arguments for flexibility and precision in small-sample settings. Regarding flexibility, several of the models that can be fitted only in one stage may not be of serious interest to most meta-analysis practitioners. Regarding precision, we consider fixed- and random-effects meta-analysis and see that, for a model making certain assumptions, the number of stages used to fit this model is irrelevant; the precision will be approximately equal. Meta-analysts should choose modelling assumptions carefully. Sometimes relevant models can only be fitted in one stage. Otherwise, meta-analysts are free to use whichever procedure is most convenient to fit the identified model. © 2018 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

Control of a Two-Stage Direct Power Converter with a Single Voltage Sensor Mounted in the Intermediary Circuit

DEFF Research Database (Denmark)

Klumpner, Christian; Wheeler, P.; Blaabjerg, Frede

2004-01-01

Controlling a converter requires not only a powerful processors but also accurate voltage and current sensors and fast and precise analogue-digital converters, which increase the cost per kW of the assembly, especially in the low power range. A matrix converter requires less transducers than a back...... converters but in two stages (AC/DC/AC) without using energy storage in the intermediary circuit. They also offer the possibility to reduce the number of switches compared to the standard single-stage matrix converter. This paper presents a new method to control a two-stage DPC providing sine-wave in sine...

Surgical reconstruction of pressure ulcer defects: a single- or two-stage procedure?

LENUS (Irish Health Repository)

Laing, Tereze A

2012-02-01

BACKGROUND: The surgical management of pressure ulcers traditionally involved staged procedures, with initial debridement of necrotic or infected material followed by reconstruction at a later date when the wound was deemed viable and free of gross infection. However, over the past decade, it has been suggested that a single-stage procedure, combining initial debridement and definitive reconstruction, may provide advantages over staged surgery. We present our experience with the staged approach and review the current evidence for both methods. SUBJECTS AND SETTINGS: : We reviewed medical records of all patients referred to our service for pressure ulcer management between October 2001 and October 2007. The National Rehabilitation Hospital is the national center in Ireland for primary rehabilitation of adults and children suffering from spinal and brain injury, serving patients locally and from around the country. METHODS: All subjects who were managed surgically underwent a 2-stage procedure, with initial debridement and subsequent reconstruction. The main outcome measures were length of hospital stay, postoperative morbidity and mortality, and time to complete ulcer healing. RESULTS: Forty-one of 108 patients with 58 pressure ulcers were managed surgically. All patients underwent initial surgical debridement and 20 patients underwent subsequent pressure ulcer reconstruction. Postreconstructive complications occurred in 5 patients (20%). The mean time to complete ulcer healing was 17.4 weeks. Partial flap necrosis occurred in 3 patients, but there were no episodes of flap failure. CONCLUSIONS: We achieved favorable results with a 2-stage reconstruction technique and suggest that the paucity of evidence related to single-stage procedures does not support a change in surgical management.

Development and testing of a two stage granular filter to improve collection efficiency

Energy Technology Data Exchange (ETDEWEB)

Rangan, R.S.; Prakash, S.G.; Chakravarti, S.; Rao, S.R.

1999-07-01

A circulating bed granular filter (CBGF) with a single filtration stage was tested with a PFB combustor in the Coal Research Facility of BHEL R and D in Hyderabad during the years 1993--95. Filter outlet dust loading varied between 20--50 mg/Nm{sup 3} for an inlet dust loading of 5--8 gms/Nm{sup 3}. The results were reported in Fluidized Bed Combustion-Volume 2, ASME 1995. Though the outlet consists of predominantly fine particulates below 2 microns, it is still beyond present day gas turbine specifications for particulate concentration. In order to enhance the collection efficiency, a two-stage granular filtration concept was evolved, wherein the filter depth is divided between two stages, accommodated in two separate vertically mounted units. The design also incorporates BHEL's scale-up concept of multiple parallel stages. The two-stage concept minimizes reentrainment of captured dust by providing clean granules in the upper stage, from where gases finally exit the filter. The design ensures that dusty gases come in contact with granules having a higher dust concentration at the bottom of the two-stage unit, where most of the cleaning is completed. A second filtration stage of cleaned granules is provided in the top unit (where the granules are returned to the system after dedusting) minimizing reentrainment. Tests were conducted to determine the optimum granule to dust ratio (G/D ratio) which decides the granule circulation rate required for the desired collection efficiency. The data brings out the importance of pre-separation and the limitation on inlet dust loading for any continuous system of granular filtration. Collection efficiencies obtained were much higher (outlet dust being 3--9 mg/Nm{sub 3}) than in the single stage filter tested earlier for similar dust loading at the inlet. The results indicate that two-stage granular filtration has a high potential for HTHT application with fewer risks as compared to other systems under development.

Performance and genome-centric metagenomics of thermophilic single and two-stage anaerobic digesters treating cheese wastes

DEFF Research Database (Denmark)

Fontana, Alessandra; Campanaro, Stefano; Treu, Laura

2018-01-01

-depth characterization of the microbial community structure using genome-centric metagenomics. Both reactor configurations showed acidification problems under the tested organic loading rates (OLRs) of 3.6 and 2.4 g COD/L-reactor day and the hydraulic retention time (HRT) of 15 days. However, the two-stage design...... of the main population genomes highlighted specific metabolic pathways responsible for the AD process and the mechanisms of main intermediates production. Particularly, the acetate accumulation experienced by the single stage configuration was mainly correlated to the low abundant syntrophic acetate oxidizer...

Poppy Crop Height and Capsule Volume Estimation from a Single UAS Flight

Directory of Open Access Journals (Sweden)

Faheem Iqbal

2017-06-01

Full Text Available The objective of this study was to estimate poppy plant height and capsule volume with remote sensing using an Unmanned Aircraft System (UAS. Data were obtained from field measurements and UAS flights over two poppy crops at Cambridge and Cressy in Tasmania. Imagery acquired from the UAS was used to produce dense point clouds using structure from motion (SfM and multi-view stereopsis (MVS techniques. Dense point clouds were used to generate a digital surface model (DSM and orthophoto mosaic. An RGB index was derived from the orthophoto to extract the bare ground spaces. This bare ground space mask was used to filter the points on the ground, and a digital terrain model (DTM was interpolated from these points. Plant height values were estimated by subtracting the DSM and DTM to generate a Crop Height Model (CHM. UAS-derived plant height (PH and field measured PH in Cambridge were strongly correlated with R2 values ranging from 0.93 to 0.97 for Transect 1 and Transect 2, respectively, while at Cressy results from a single flight provided R2 of 0.97. Therefore, the proposed method can be considered an important step towards crop surface model (CSM generation from a single UAS flight in situations where a bare ground DTM is unavailable. High correlations were found between UAS-derived PH and poppy capsule volume (CV at capsule formation stage (R2 0.74, with relative error of 19.62%. Results illustrate that plant height can be reliably estimated for poppy crops based on a single UAS flight and can be used to predict opium capsule volume at capsule formation stage.

Two-stage implant systems.

Science.gov (United States)

Fritz, M E

1999-06-01

Since the advent of osseointegration approximately 20 years ago, there has been a great deal of scientific data developed on two-stage integrated implant systems. Although these implants were originally designed primarily for fixed prostheses in the mandibular arch, they have been used in partially dentate patients, in patients needing overdentures, and in single-tooth restorations. In addition, this implant system has been placed in extraction sites, in bone-grafted areas, and in maxillary sinus elevations. Often, the documentation of these procedures has lagged. In addition, most of the reports use survival criteria to describe results, often providing overly optimistic data. It can be said that the literature describes a true adhesion of the epithelium to the implant similar to adhesion to teeth, that two-stage implants appear to have direct contact somewhere between 50% and 70% of the implant surface, that the microbial flora of the two-stage implant system closely resembles that of the natural tooth, and that the microbiology of periodontitis appears to be closely related to peri-implantitis. In evaluations of the data from implant placement in all of the above-noted situations by means of meta-analysis, it appears that there is a strong case that two-stage dental implants are successful, usually showing a confidence interval of over 90%. It also appears that the mandibular implants are more successful than maxillary implants. Studies also show that overdenture therapy is valid, and that single-tooth implants and implants placed in partially dentate mouths have a success rate that is quite good, although not quite as high as in the fully edentulous dentition. It would also appear that the potential causes of failure in the two-stage dental implant systems are peri-implantitis, placement of implants in poor-quality bone, and improper loading of implants. There are now data addressing modifications of the implant surface to alter the percentage of

Two cycles of cisplatin-based chemotherapy for low-volume stage II seminoma: results of a retrospective, single-center case series.

Science.gov (United States)

Pichler, Renate; Leonhartsberger, Nicolai; Stöhr, Brigitte; Horninger, Wolfgang; Steiner, Hannes

2012-01-01

To report on the oncological outcome and toxicity of patients treated with 2 cycles of cisplatin-based chemotherapy for low-volume metastatic stage II seminoma. We retrospectively identified a case series of 15 patients with seminoma stage IIA (26.7%) and IIB (73.3%) who underwent chemotherapy consisting of 2 cycles of cisplatin, etoposide and bleomycin (PEB) (cisplatin 20 mg/m(2) on days 1-5, etoposide 100 mg/m(2) on days 1-5, bleomycin 30 mg on days 1, 8 and 15) according to patient preference (refusing a 3rd cycle of PEB) or institutional practice in the last decades. Complete staging before chemotherapy was available in all patients. Patient age, the side and diameter of the primary tumor, the size of the lymph nodes before and after chemotherapy, acute and late toxicity of chemotherapy, the incidence of second malignancies, the relapse-free rate and cancer-specific mortality were recorded. Chemotherapy was well tolerated and no episode of febrile neutropenia occurred. Thrombocytopenia grade 4 was not seen in any patient, while leukopenia grade 4 was observed in 4 (26.6%) patients. The mean (range) lymph node size decreased significantly from 2.54 cm (1.1-4.0) before chemotherapy to 0.75 cm (0.4-2.2) after chemotherapy (p < 0.001). After a median (range) follow-up of 60 (13-185) months, no patient had relapsed, no patient had died as a result of seminoma and second malignancy was seen in only 1 (6.6%) patient. These excellent long-term results from a retrospective case series of 2 cycles of PEB in stage IIA/IIB seminoma patients represent a hint for further research with a view to reducing treatment burden. However, these incidental findings should be studied in prospective trials prior to drawing any conclusions. Copyright © 2013 S. Karger AG, Basel.

Two-stage dental implants inserted in a one-stage procedure : a prospective comparative clinical study

NARCIS (Netherlands)

Heijdenrijk, Kees

2002-01-01

The results of this study indicate that dental implants designed for a submerged implantation procedure can be used in a single-stage procedure and may be as predictable as one-stage implants. Although one-stage implant systems and two-stage.

Two-Stage Dynamic Pricing and Advertising Strategies for Online Video Services

Directory of Open Access Journals (Sweden)

Zhi Li

2017-01-01

Full Text Available As the demands for online video services increase intensively, the selection of business models has drawn the great attention of online providers. Among them, pay-per-view mode and advertising mode are two important resource modes, where the reasonable fee charge and suitable volume of ads need to be determined. This paper establishes an analytical framework studying the optimal dynamic pricing and advertising strategies for online providers; it shows how the strategies are influenced by the videos available time and the viewers’ emotional factor. We create the two-stage strategy of revenue models involving a single fee mode and a mixed fee-free mode and find out the optimal fee charge and advertising level of online video services. According to the results, the optimal video price and ads volume dynamically vary over time. The viewer’s aversion level to advertising has direct effects on both the volume of ads and the number of viewers who have selected low-quality content. The optimal volume of ads decreases with the increase of ads-aversion coefficient, while increasing as the quality of videos increases. The results also indicate that, in the long run, a pure fee mode or free mode is the optimal strategy for online providers.

Thermodynamic analysis of single-stage and multi-stage adsorption refrigeration cycles with activated carbon–ammonia working pair

International Nuclear Information System (INIS)

Xu, S.Z.; Wang, L.W.; Wang, R.Z.

2016-01-01

Highlights: • Activated carbon–ammonia multi-stage adsorption refrigerator was analyzed. • COP, exergetic efficiency and entropy production of cycles were calculated. • Single-stage cycle usually has the advantages of simple structure and high COP. • Multi-stage cycles adapt to critical conditions better than single-stage cycle. • Boundary conditions for choosing optimal cycle were summarized as tables. - Abstract: Activated carbon–ammonia multi-stage adsorption refrigeration cycle was analyzed in this article, which realized deep-freezing for evaporating temperature under −18 °C with heating source temperature much lower than 100 °C. Cycle mathematical models for single, two and three-stage cycles were established on the basis of thorough thermodynamic analysis. According to simulation results of thermodynamic evaluation indicators such as COP (coefficient of performance), exergetic efficiency and cycle entropy production, multi-stage cycle adapts to high condensing temperature, low evaporating temperature and low heating source temperature well. Proposed cycle with selected working pair can theoretically work under very severe conditions, such as −25 °C evaporating temperature, 40 °C condensing temperature, and 70 °C heating source temperature, but under these working conditions it has the drawback of low cycle adsorption quantity. It was found that both COP and exergetic efficiency are of great reference value in the choice of cycle, whereas entropy production is not so useful for cycle stage selection. Finally, the application boundary conditions of single-stage, two-stage, and three-stage cycles were summarized as tables according to the simulation results, which provides reference for choosing optimal cycle under different conditions.

Two-stage precipitation of plutonium trifluoride

International Nuclear Information System (INIS)

Luerkens, D.W.

1984-04-01

Plutonium trifluoride was precipitated using a two-stage precipitation system. A series of precipitation experiments identified the significant process variables affecting precipitate characteristics. A mathematical precipitation model was developed which was based on the formation of plutonium fluoride complexes. The precipitation model relates all process variables, in a single equation, to a single parameter that can be used to control particle characteristics

Two-Stage Fuzzy Portfolio Selection Problem with Transaction Costs

Directory of Open Access Journals (Sweden)

Yanju Chen

2015-01-01

Full Text Available This paper studies a two-period portfolio selection problem. The problem is formulated as a two-stage fuzzy portfolio selection model with transaction costs, in which the future returns of risky security are characterized by possibility distributions. The objective of the proposed model is to achieve the maximum utility in terms of the expected value and variance of the final wealth. Given the first-stage decision vector and a realization of fuzzy return, the optimal value expression of the second-stage programming problem is derived. As a result, the proposed two-stage model is equivalent to a single-stage model, and the analytical optimal solution of the two-stage model is obtained, which helps us to discuss the properties of the optimal solution. Finally, some numerical experiments are performed to demonstrate the new modeling idea and the effectiveness. The computational results provided by the proposed model show that the more risk-averse investor will invest more wealth in the risk-free security. They also show that the optimal invested amount in risky security increases as the risk-free return decreases and the optimal utility increases as the risk-free return increases, whereas the optimal utility increases as the transaction costs decrease. In most instances the utilities provided by the proposed two-stage model are larger than those provided by the single-stage model.

A clinical case of single-stage correction of penetration combined orofacial defect with two microsurgical autografts

Directory of Open Access Journals (Sweden)

A. D. Kaprin

2015-01-01

Full Text Available After surgical treatment for locally advanced oral tumors with resection of soft tissues, mucosal membrane, and facial skeletal structures, there are penetration combined defects, removal of which is a challenge for reconstructive surgeons. Mandibular repair is one of the problems in the correction of combined oral defects. Surgeons use different grafts to remove mandibular defects. One-flap transplantation does not always solve all reconstruction problems and ensure the repair of the mucosal membrane, a soft-tissue component, skin integuments, and facial skeleton.The authors describe a clinical case of successful single-stage correction of penetration combined orofacial defect after resection of the tongue, mouth floor, en bloc resection of the lower jaw and mental soft tissues, bilateral cervical supramyochoroidal lymphadenectomy, stage LCL CM mandibular defect formation after J. Boyd, by using two microsurgical autografts (a peroneal skin-muscle-skin autograft and a radial skin-fascia one in a 39-year-old female patient clinically diagnosed with carcinoma of the left mandibular alveolar ridge mucosa, Stage IVA (T4аN0M0.The Department of Microsurgery, P.A. Herzen Moscow Oncology Research Institute, Ministry of Health of Russia, has gained experience in comprehensively correcting extensive combined maxillofacial defects with two or more grafts in 27 patients who underwent autografting with a total of 73 flaps. The most functionally incapacitating and life-incompatible defect was removed at Stage 1 of reconstructive treatment. Delayed reconstruction was made after a complex of specialized antitumor therapy and assessment of treatment results in the absence of progressive growth. A great problem during multi-stage defect correction is presented by the lack of recipient vessels after cervical lymphadenectomy, the presence of soft tissue scar changes, trismus, temporomandibular joint ankylosis, contractures and displacement of the edges of the

Delayed Single Stage Perineal Posterior Urethroplasty.

Science.gov (United States)

Ali, Shahzad; Shahnawaz; Shahzad, Iqbal; Baloch, Muhammad Umar

2015-06-01

To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Descriptive case series. Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patient's age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3%) experienced recurrent stricture during first 10 months. Five (16.6%) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6%) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3% with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures.

CFD simulations of compressed air two stage rotary Wankel expander – Parametric analysis

International Nuclear Information System (INIS)

Sadiq, Ghada A.; Tozer, Gavin; Al-Dadah, Raya; Mahmoud, Saad

2017-01-01

Highlights: • CFD ANSYS-Fluent 3D simulation of Wankel expander is developed. • Single and two-stage expander’s performance is compared. • Inlet and outlet ports shape and configurations are investigated. • Isentropic efficiency of two stage Wankel expander of 91% is achieved. - Abstract: A small scale volumetric Wankel expander is a powerful device for small-scale power generation in compressed air energy storage (CAES) systems and Organic Rankine cycles powered by different heat sources such as, biomass, low temperature geothermal, solar and waste heat leading to significant reduction in CO_2 emissions. Wankel expanders outperform other types of expander due to their ability to produce two power pulses per revolution per chamber additional to higher compactness, lower noise and vibration and lower cost. In this paper, a computational fluid dynamics (CFD) model was developed using ANSYS 16.2 to simulate the flow dynamics for a single and two stage Wankel expanders and to investigate the effect of port configurations, including size and spacing, on the expander’s power output and isentropic efficiency. Also, single-stage and two-stage expanders were analysed with different operating conditions. Single-stage 3D CFD results were compared to published work showing close agreement. The CFD modelling was used to investigate the performance of the rotary device using air as an ideal gas with various port diameters ranging from 15 mm to 50 mm; port spacing varying from 28 mm to 66 mm; different Wankel expander sizes (r = 48, e = 6.6, b = 32) mm and (r = 58, e = 8, b = 40) mm both as single-stage and as two-stage expanders with different configurations and various operating conditions. Results showed that the best Wankel expander design for a single-stage was (r = 48, e = 6.6, b = 32) mm, with the port diameters 20 mm and port spacing equal to 50 mm. Moreover, combining two Wankel expanders horizontally, with a larger one at front, produced 8.52 kW compared

Advantages of using a two-switch forward in single-stage power factor corrected power supplies

DEFF Research Database (Denmark)

Petersen, Lars

2000-01-01

A single-stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (discontinues conduction mode) and it is shown that this operation mode ensures the intermediate DC-bus to be controlled only by means of circuit...... supply has been implemented. The measured efficiency is between 85% and 88.5% in the range 30 W-500 W and the measured power factor at full load is 0.95....... parameters and therefore independent of load variations. The DCM operation often has a diminishing effect on the efficiency but by use of the two-switch topology high efficiency with minimum circuit complexity can be achieved in this mode. A 500 W 70 V prototype of the two-switch boost-forward PFC power...

Delayed Single Stage Perineal Posterior Urethroplasty

International Nuclear Information System (INIS)

Ali, S.; Shahnawaz; Shahzad, I.; Baloch, M. U.

2015-01-01

Objective: To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Study Design: Descriptive case series. Place and Duration of Study: Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Methodology: Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Results: Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patients age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3 percentage) experienced recurrent stricture during first 10 months. Five (16.6 percentage) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6 percentage) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3 percentage with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Conclusion: Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures. (author)

Experimental study on two-stage compression refrigeration/heat pump system with dual-cylinder rolling piston compressor

International Nuclear Information System (INIS)

Shuxue, Xu; Guoyuan, Ma

2014-01-01

A thermodynamically analytical model on the two-stage compression refrigeration/heat pump system with vapor injection was derived. The optimal volume ratio of the high-pressure cylinder to the low-pressure one has been discussed under both cooling and heating conditions. Based on the above research, the prototype was developed and its experimental setup established. A comprehensive experiments for the prototype have been conducted, and the results show that, compared with the single-stage compression heat pump system, the cooling capacity and cooling COP can increase 5%–15% and 10–12%, respectively. Also, the heating capacity with the evaporating temperature ranging from 0.3 to 3 °C is 92–95% of that under the rate condition with the evaporating temperature of 7 °C, and 58% when the evaporation temperature is between −28 °C and −24 °C. -- Highlights: • The volume ratio of the compressor is between 0.65 and 0.78 and the relative vapor injection mass ranges from 15% to 20%. • The cooling capacity and COP of the two-stage compression system can improve 5%–15% and 10%–12%. • The heating capacity can also be improved under low temperature condition

Two-stage free electron laser research

Science.gov (United States)

Segall, S. B.

1984-10-01

KMS Fusion, Inc. began studying the feasibility of two-stage free electron lasers for the Office of Naval Research in June, 1980. At that time, the two-stage FEL was only a concept that had been proposed by Luis Elias. The range of parameters over which such a laser could be successfully operated, attainable power output, and constraints on laser operation were not known. The primary reason for supporting this research at that time was that it had the potential for producing short-wavelength radiation using a relatively low voltage electron beam. One advantage of a low-voltage two-stage FEL would be that shielding requirements would be greatly reduced compared with single-stage short-wavelength FEL's. If the electron energy were kept below about 10 MeV, X-rays, generated by electrons striking the beam line wall, would not excite neutron resonance in atomic nuclei. These resonances cause the emission of neutrons with subsequent induced radioactivity. Therefore, above about 10 MeV, a meter or more of concrete shielding is required for the system, whereas below 10 MeV, a few millimeters of lead would be adequate.

Comparing a single-stage geocoding method to a multi-stage geocoding method: how much and where do they disagree?

Directory of Open Access Journals (Sweden)

Rice Kenneth

2007-03-01

Full Text Available Abstract Background Geocoding methods vary among spatial epidemiology studies. Errors in the geocoding process and differential match rates may reduce study validity. We compared two geocoding methods using 8,157 Washington State addresses. The multi-stage geocoding method implemented by the state health department used a sequence of local and national reference files. The single-stage method used a single national reference file. For each address geocoded by both methods, we measured the distance between the locations assigned by each method. Area-level characteristics were collected from census data, and modeled as predictors of the discordance between geocoded address coordinates. Results The multi-stage method had a higher match rate than the single-stage method: 99% versus 95%. Of 7,686 addresses were geocoded by both methods, 96% were geocoded to the same census tract by both methods and 98% were geocoded to locations within 1 km of each other by the two methods. The distance between geocoded coordinates for the same address was higher in sparsely populated and low poverty areas, and counties with local reference files. Conclusion The multi-stage geocoding method had a higher match rate than the single-stage method. An examination of differences in the location assigned to the same address suggested that study results may be most sensitive to the choice of geocoding method in sparsely populated or low-poverty areas.

Comparative effectiveness of one-stage versus two-stage basilic vein transposition arteriovenous fistulas.

Science.gov (United States)

Ghaffarian, Amir A; Griffin, Claire L; Kraiss, Larry W; Sarfati, Mark R; Brooke, Benjamin S

2018-02-01

Basilic vein transposition (BVT) fistulas may be performed as either a one-stage or two-stage operation, although there is debate as to which technique is superior. This study was designed to evaluate the comparative clinical efficacy and cost-effectiveness of one-stage vs two-stage BVT. We identified all patients at a single large academic hospital who had undergone creation of either a one-stage or two-stage BVT between January 2007 and January 2015. Data evaluated included patient demographics, comorbidities, medication use, reasons for abandonment, and interventions performed to maintain patency. Costs were derived from the literature, and effectiveness was expressed in quality-adjusted life-years (QALYs). We analyzed primary and secondary functional patency outcomes as well as survival during follow-up between one-stage and two-stage BVT procedures using multivariate Cox proportional hazards models and Kaplan-Meier analysis with log-rank tests. The incremental cost-effectiveness ratio was used to determine cost savings. We identified 131 patients in whom 57 (44%) one-stage BVT and 74 (56%) two-stage BVT fistulas were created among 8 different vascular surgeons during the study period that each performed both procedures. There was no significant difference in the mean age, male gender, white race, diabetes, coronary disease, or medication profile among patients undergoing one- vs two-stage BVT. After fistula transposition, the median follow-up time was 8.3 months (interquartile range, 3-21 months). Primary patency rates of one-stage BVT were 56% at 12-month follow-up, whereas primary patency rates of two-stage BVT were 72% at 12-month follow-up. Patients undergoing two-stage BVT also had significantly higher rates of secondary functional patency at 12 months (57% for one-stage BVT vs 80% for two-stage BVT) and 24 months (44% for one-stage BVT vs 73% for two-stage BVT) of follow-up (P < .001 using log-rank test). However, there was no significant difference

Study on a high capacity two-stage free piston Stirling cryocooler working around 30 K

Science.gov (United States)

Wang, Xiaotao; Zhu, Jian; Chen, Shuai; Dai, Wei; Li, Ke; Pang, Xiaomin; Yu, Guoyao; Luo, Ercang

2016-12-01

This paper presents a two-stage high-capacity free-piston Stirling cryocooler driven by a linear compressor to meet the requirement of the high temperature superconductor (HTS) motor applications. The cryocooler system comprises a single piston linear compressor, a two-stage free piston Stirling cryocooler and a passive oscillator. A single stepped displacer configuration was adopted. A numerical model based on the thermoacoustic theory was used to optimize the system operating and structure parameters. Distributions of pressure wave, phase differences between the pressure wave and the volume flow rate and different energy flows are presented for a better understanding of the system. Some characterizing experimental results are presented. Thus far, the cryocooler has reached a lowest cold-head temperature of 27.6 K and achieved a cooling power of 78 W at 40 K with an input electric power of 3.2 kW, which indicates a relative Carnot efficiency of 14.8%. When the cold-head temperature increased to 77 K, the cooling power reached 284 W with a relative Carnot efficiency of 25.9%. The influences of different parameters such as mean pressure, input electric power and cold-head temperature are also investigated.

Single-stage laparoscopic common bile duct exploration and cholecystectomy versus two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy for patients with concomitant gallbladder stones and common bile duct stones: a randomized controlled trial.

Science.gov (United States)

Bansal, Virinder Kumar; Misra, Mahesh C; Rajan, Karthik; Kilambi, Ragini; Kumar, Subodh; Krishna, Asuri; Kumar, Atin; Pandav, Chandrakant S; Subramaniam, Rajeshwari; Arora, M K; Garg, Pramod Kumar

2014-03-01

The ideal method for managing concomitant gallbladder stones and common bile duct (CBD) stones is debatable. The currently preferred method is two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy (LC). This prospective randomized trial compared the success and cost effectiveness of single- and two-stage management of patients with concomitant gallbladder and CBD stones. Consecutive patients with concomitant gallbladder and CBD stones were randomized to either single-stage laparoscopic CBD exploration and cholecystectomy (group 1) or endoscopic retrograde cholangiopancreatography (ERCP) for endoscopic extraction of CBD stones followed by LC (group 2). Success was defined as complete clearance of CBD and cholecystectomy by the intended method. Cost effectiveness was measured using the incremental cost-effectiveness ratio. Intention-to-treat analysis was performed to compare outcomes. From February 2009 to October 2012, 168 patients were randomized: 84 to the single-stage procedure (group 1) and 84 to the two-stage procedure (group 2). Both groups were matched with regard to demographic and clinical parameters. The success rates of laparoscopic CBD exploration and ERCP for clearance of CBD were similar (91.7 vs. 88.1 %). The overall success rate also was comparable: 88.1 % in group 1 and 79.8 % in group 2 (p = 0.20). Direct choledochotomy was performed in 83 of the 84 patients. The mean operative time was significantly longer in group 1 (135.7 ± 36.6 vs. 72.4 ± 27.6 min; p ≤ 0.001), but the overall hospital stay was significantly shorter (4.6 ± 2.4 vs. 5.3 ± 6.2 days; p = 0.03). Group 2 had a significantly greater number of procedures per patient (p gallbladder and CBD stones had similar success and complication rates, but the single-stage strategy was better in terms of shorter hospital stay, need for fewer procedures, and cost effectiveness.

Quantum mechanics two volumes bound as one

CERN Document Server

Messiah, Albert

2014-01-01

""Strongly recommended"" by the American Journal of Physics, this volume serves as a text for advanced undergraduates and graduate students of physics as well as a reference for professionals. Clear in its presentation and scrupulous in its attention to detail, the treatment originally appeared in a two-volume French edition. This convenient single-volume translation begins with formalism and its interpretation, starting with the origins of quantum theory and examinations of matter waves and the Schrödinger equation, one-dimensional quantized systems, the uncertainty relations, and the mathema

Managing uncertainty - a qualitative study of surgeons' decision-making for one-stage and two-stage revision surgery for prosthetic hip joint infection.

Science.gov (United States)

Moore, Andrew J; Blom, Ashley W; Whitehouse, Michael R; Gooberman-Hill, Rachael

2017-04-12

Approximately 88,000 primary hip replacements are performed in England and Wales each year. Around 1% go on to develop deep prosthetic joint infection. Between one-stage and two-stage revision arthroplasty best treatment options remain unclear. Our aims were to characterise consultant orthopaedic surgeons' decisions about performing either one-stage or two-stage revision surgery for patients with deep prosthetic infection (PJI) after hip arthroplasty, and to identify whether a randomised trial comparing one-stage with two-stage revision would be feasible. Semi-structured interviews were conducted with 12 consultant surgeons who perform revision surgery for PJI after hip arthroplasty at 5 high-volume National Health Service (NHS) orthopaedic departments in England and Wales. Surgeons were interviewed before the development of a multicentre randomised controlled trial. Data were analysed using a thematic approach. There is no single standardised surgical intervention for the treatment of PJI. Surgeons balance multiple factors when choosing a surgical strategy which include multiple patient-related factors, their own knowledge and expertise, available infrastructure and the infecting organism. Surgeons questioned whether it was appropriate that the two-stage revision remained the best treatment, and some surgeons' willingness to consider more one-stage revisions had increased over recent years and were influenced by growing evidence showing equivalence between surgical techniques, and local observations of successful one-stage revisions. Custom-made articulating spacers was a practice that enabled uncertainty to be managed in the absence of definitive evidence about the superiority of one surgical technique over the other. Surgeons highlighted the need for research evidence to inform practice and thought that a randomised trial to compare treatments was needed. Most surgeons thought that patients who they treated would be eligible for trial participation in instances

Single stage reconstruction of complex anterior urethral strictures

Directory of Open Access Journals (Sweden)

Deepak Dubey

2001-01-01

Full Text Available Purpose: Single stage reconstruction of long, com-plex urethral strictures is technically demanding and may require the use of more than one tissue transfer technique. We describe our experience in the manage-ment of such strictures with a variety of urethroplasty techniques. Materials and Methods: Between 1989 and 1999, 25 men (mean age 38.5 years underwent single stage re-construction of panurethral, multiple segment or focally dense strictures [mean length 11.2 cm (range 8-17 cm]. 8 patients had combined substitution urethroplasty with a circumpenile fasciocutaneous flap and a free graft of bladder/buccal mucosa or tunica vaginalis . flap. In 10 patients a single tissue transfer technique was used. 3 patients underwent an augmented roof/floor strip ure-throplasty with a penile skin flap. 4 patients with multi-ple segment strictures (separate pendulous and bulbar underwent distal onlay flap and proximal anastomotic urethroplasty. Results: The median ,follow-up was 46.5 months (range 6-88 months. The mean postoperative flow rate improved to 22.5 ml/sec. 2 patients developed fistulae requiring repair. Recurrent stricture developed in 5 (20.8% patients, of which 2 were managed with visual internal urethrotomy, 2 with anastomotic urethroplasty and 1 with a two-stage procedure. Pseudodiverticulum and post-void dribbling were seen in 6 (25% patients. Conclusions: Successful outcome of single stage re-construction of long complex strictures can be achieved with a combination of various tissue transfer methods. The urologist who has a thorough knowledge of penile skin and urethral vascular anatomy and a wide array of substitution techniques in his armamentarium can un-dertake approach to such strictures.

A Cost-Effective Power Ramp-Rate Control Strategy for Single-Phase Two-Stage Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

In the case of a wide-scale adoption of grid-connected Photovoltaic (PV) systems, more fluctuated power will be injected into the grid due to the intermittency of solar PV energy. A sudden change in the PV power can potentially induce grid voltage fluctuations, and thus challenge the stability......-point. Experiments conducted on a 3-kW single-phase two-stage grid-connected PV system have verified that the proposed solution can accomplish fast dynamics, high accuracy, and high robustness in the power ramp-rate control for PV systems....

Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

KAUST Repository

Alfazazi, Adamu

2016-08-10

The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

Wide-bandwidth bilateral control using two-stage actuator system

International Nuclear Information System (INIS)

Kokuryu, Saori; Izutsu, Masaki; Kamamichi, Norihiro; Ishikawa, Jun

2015-01-01

This paper proposes a two-stage actuator system that consists of a coarse actuator driven by a ball screw with an AC motor (the first stage) and a fine actuator driven by a voice coil motor (the second stage). The proposed two-stage actuator system is applied to make a wide-bandwidth bilateral control system without needing expensive high-performance actuators. In the proposed system, the first stage has a wide moving range with a narrow control bandwidth, and the second stage has a narrow moving range with a wide control bandwidth. By consolidating these two inexpensive actuators with different control bandwidths in a complementary manner, a wide bandwidth bilateral control system can be constructed based on a mechanical impedance control. To show the validity of the proposed method, a prototype of the two-stage actuator system has been developed and basic performance was evaluated by experiment. The experimental results showed that a light mechanical impedance with a mass of 10 g and a damping coefficient of 2.5 N/(m/s) that is an important factor to establish good transparency in bilateral control has been successfully achieved and also showed that a better force and position responses between a master and slave is achieved by using the proposed two-stage actuator system compared with a narrow bandwidth case using a single ball screw system. (author)

Automatic sleep stage classification using two facial electrodes.

Science.gov (United States)

Virkkala, Jussi; Velin, Riitta; Himanen, Sari-Leena; Värri, Alpo; Müller, Kiti; Hasan, Joel

2008-01-01

Standard sleep stage classification is based on visual analysis of central EEG, EOG and EMG signals. Automatic analysis with a reduced number of sensors has been studied as an easy alternative to the standard. In this study, a single-channel electro-oculography (EOG) algorithm was developed for separation of wakefulness, SREM, light sleep (S1, S2) and slow wave sleep (S3, S4). The algorithm was developed and tested with 296 subjects. Additional validation was performed on 16 subjects using a low weight single-channel Alive Monitor. In the validation study, subjects attached the disposable EOG electrodes themselves at home. In separating the four stages total agreement (and Cohen's Kappa) in the training data set was 74% (0.59), in the testing data set 73% (0.59) and in the validation data set 74% (0.59). Self-applicable electro-oculography with only two facial electrodes was found to provide reasonable sleep stage information.

One-stage versus two-stage exchange arthroplasty for infected total knee arthroplasty: a systematic review.

Science.gov (United States)

Nagra, Navraj S; Hamilton, Thomas W; Ganatra, Sameer; Murray, David W; Pandit, Hemant

2016-10-01

Infection complicating total knee arthroplasty (TKA) has serious implications. Traditionally the debate on whether one- or two-stage exchange arthroplasty is the optimum management of infected TKA has favoured two-stage procedures; however, a paradigm shift in opinion is emerging. This study aimed to establish whether current evidence supports one-stage revision for managing infected TKA based on reinfection rates and functional outcomes post-surgery. MEDLINE/PubMed and CENTRAL databases were reviewed for studies that compared one- and two-stage exchange arthroplasty TKA in more than ten patients with a minimum 2-year follow-up. From an initial sample of 796, five cohort studies with a total of 231 patients (46 single-stage/185 two-stage; median patient age 66 years, range 61-71 years) met inclusion criteria. Overall, there were no significant differences in risk of reinfection following one- or two-stage exchange arthroplasty (OR -0.06, 95 % confidence interval -0.13, 0.01). Subgroup analysis revealed that in studies published since 2000, one-stage procedures have a significantly lower reinfection rate. One study investigated functional outcomes and reported that one-stage surgery was associated with superior functional outcomes. Scarcity of data, inconsistent study designs, surgical technique and antibiotic regime disparities limit recommendations that can be made. Recent studies suggest one-stage exchange arthroplasty may provide superior outcomes, including lower reinfection rates and superior function, in select patients. Clinically, for some patients, one-stage exchange arthroplasty may represent optimum treatment; however, patient selection criteria and key components of surgical and post-operative anti-microbial management remain to be defined. III.

Two-Stage Latissimus Dorsi Flap with Implant for Unilateral Breast Reconstruction: Getting the Size Right

Directory of Open Access Journals (Sweden)

Jiajun Feng

2016-03-01

Full Text Available BackgroundThe aim of unilateral breast reconstruction after mastectomy is to craft a natural-looking breast with symmetry. The latissimus dorsi (LD flap with implant is an established technique for this purpose. However, it is challenging to obtain adequate volume and satisfactory aesthetic results using a one-stage operation when considering factors such as muscle atrophy, wound dehiscence and excessive scarring. The two-stage reconstruction addresses these difficulties by using a tissue expander to gradually enlarge the skin pocket which eventually holds an appropriately sized implant.MethodsWe analyzed nine patients who underwent unilateral two-stage LD reconstruction. In the first stage, an expander was placed along with the LD flap to reconstruct the mastectomy defect, followed by gradual tissue expansion to achieve overexpansion of the skin pocket. The final implant volume was determined by measuring the residual expander volume after aspirating the excess saline. Finally, the expander was replaced with the chosen implant.ResultsThe average volume of tissue expansion was 460 mL. The resultant expansion allowed an implant ranging in volume from 255 to 420 mL to be placed alongside the LD muscle. Seven patients scored less than six on the relative breast retraction assessment formula for breast symmetry, indicating excellent breast symmetry. The remaining two patients scored between six and eight, indicating good symmetry.ConclusionsThis approach allows the size of the eventual implant to be estimated after the skin pocket has healed completely and the LD muscle has undergone natural atrophy. Optimal reconstruction results were achieved using this approach.

A Two-Stage Fuzzy Logic Control Method of Traffic Signal Based on Traffic Urgency Degree

OpenAIRE

Yan Ge

2014-01-01

City intersection traffic signal control is an important method to improve the efficiency of road network and alleviate traffic congestion. This paper researches traffic signal fuzzy control method on a single intersection. A two-stage traffic signal control method based on traffic urgency degree is proposed according to two-stage fuzzy inference on single intersection. At the first stage, calculate traffic urgency degree for all red phases using traffic urgency evaluation module and select t...

A numerical investigation on the unstable flow in a single stage of an axial compressors

CERN Document Server

Farhanieh, B; Ghorbanian, K

2003-01-01

An unsteady two-dimensional finite-volume solver was developed based on Van Leer's flux splitting algorithm in conjunction with sup M onotonic Upstream Scheme for Conservation Laws sup l imiters to improve the order of accuracy and the two-layer Baldwin-Lomax turbulence model was also implemented. Two test cases were prepared to validate the solver. The computed results were compared with the experimental data and a good agreement validated the solver. Finally, the solver was used for the flow through a multi-blade stage of an axial compressor in its off-design condition. The computed results showed a rotating stall-like instability with a periodic behavior. To investigate the flow properties during the instability condition, the flow pattern, vortex properties and the axial velocity were studied. It was concluded that the instability vortices in the multi-blade cascade do not have the same generation history of the separated vortices over a single body.

FDG-PET/CT Imaging for Staging and Target Volume Delineation in Preoperative Conformal Radiotherapy of Rectal Cancer

International Nuclear Information System (INIS)

Bassi, Maria Chiara; Turri, Lucia; Sacchetti, Gianmauro; Loi, Gianfranco; Cannillo, Barbara; La Mattina, Pierdaniele; Brambilla, Marco; Inglese, Eugenio; Krengli, Marco

2008-01-01

Purpose: To investigate the potential impact of using 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on staging and target volume delineation for patients affected by rectal cancer and candidates for preoperative conformal radiotherapy. Methods and Materials: Twenty-five patients diagnosed with rectal cancer T3-4 N0-1 M0-1 and candidates for preoperative radiotherapy underwent PET/CT simulation after injection of 5.18 MBq/kg of FDG. Clinical stage was reassessed on the basis of FDG-PET/CT findings. The gross tumor volume (GTV) and the clinical target volume (CTV) were delineated first on CT and then on PET/CT images. The PET/CT-GTV and PET/CT-CTV were analyzed and compared with CT-GTV and CT-CTV, respectively. Results: In 4 of 25 cases (24%), PET/CT affected tumor staging or the treatment purpose. In 3 of 25 cases (12%) staged N0 M0, PET/CT showed FDG uptake in regional lymph nodes and in a case also in the liver. In a patient with a single liver metastasis PET/CT detected multiple lesions, changing the treatment intent from curative to palliative. The PET/CT-GTV and PET/CT-CTV were significantly greater than the CT-GTV (p = 0.00013) and CT-CTV (p = 0.00002), respectively. The mean difference between PET/CT-GTV and CT-GTV was 25.4% and between PET/CT-CTV and CT-CTV was 4.1%. Conclusions: Imaging with PET/CT for preoperative radiotherapy of rectal cancer may lead to a change in staging and target volume delineation. Stage variation was observed in 12% of cases and a change of treatment intent in 4%. The GTV and CTV changed significantly, with a mean increase in size of 25% and 4%, respectively

A high-power two stage traveling-wave tube amplifier

International Nuclear Information System (INIS)

Shiffler, D.; Nation, J.A.; Schachter, L.; Ivers, J.D.; Kerslick, G.S.

1991-01-01

Results are presented on the development of a two stage high-efficiency, high-power 8.76-GHz traveling-wave tube amplifier. The work presented augments previously reported data on a single stage amplifier and presents new data on the operational characteristics of two identical amplifiers operated in series and separated from each other by a sever. Peak powers of 410 MW have been obtained over the complete pulse duration of the device, with a conversion efficiency from the electron beam to microwave energy of 45%. In all operating conditions the severed amplifier showed a ''sideband''-like structure in the frequency spectrum of the microwave radiation. A similar structure was apparent at output powers in excess of 70 MW in the single stage device. The frequencies of the ''sidebands'' are not symmetric with respect to the center frequency. The maximum, single frequency, average output power was 210 MW corresponding to an amplifier efficiency of 24%. Simulation data is also presented that indicates that the short amplifiers used in this work exhibit significant differences in behavior from conventional low-power amplifiers. These include finite length effects on the gain characteristics, which may account for the observed narrow bandwidth of the amplifiers and for the appearance of the sidebands. It is also found that the bunching length for the beam may be a significant fraction of the total amplifier length

Analysis of honeybush tea (Cyclopia spp.) volatiles by comprehensive two-dimensional gas chromatography using a single-stage thermal modulator.

Science.gov (United States)

Ntlhokwe, Gaalebalwe; Tredoux, Andreas G J; Górecki, Tadeusz; Edwards, Matthew; Vestner, Jochen; Muller, Magdalena; Erasmus, Lené; Joubert, Elizabeth; Christel Cronje, J; de Villiers, André

2017-07-01

The applicability of comprehensive two-dimensional gas chromatography (GC×GC) using a single-stage thermal modulator was explored for the analysis of honeybush tea (Cyclopia spp.) volatile compounds. Headspace solid phase micro-extraction (HS-SPME) was used in combination with GC×GC separation on a non-polar × polar column set with flame ionisation (FID) detection for the analysis of fermented Cyclopia maculata, Cyclopia subternata and Cyclopia genistoides tea infusions of a single harvest season. Method optimisation entailed evaluation of the effects of several experimental parameters on the performance of the modulator, the choice of columns in both dimensions, as well as the HS-SPME extraction fibre. Eighty-four volatile compounds were identified by co-injection of reference standards. Principal component analysis (PCA) showed clear differentiation between the species based on their volatile profiles. Due to the highly reproducible separations obtained using the single-stage thermal modulator, multivariate data analysis was simplified. The results demonstrate both the complexity of honeybush volatile profiles and the potential of GC×GC separation in combination with suitable data analysis techniques for the investigation of the relationship between sensory properties and volatile composition of these products. The developed method therefore offers a fast and inexpensive methodology for the profiling of honeybush tea volatiles. Graphical abstract Surface plot obtained for the GC×GC-FID analysis of honeybush tea volatiles.

Gas pollutants removal in a single- and two-stage ejector-venturi scrubber.

Science.gov (United States)

Gamisans, Xavier; Sarrà, Montserrrat; Lafuente, F Javier

2002-03-29

The absorption of SO(2) and NH(3) from the flue gas into NaOH and H(2)SO(4) solutions, respectively has been studied using an industrial scale ejector-venturi scrubber. A statistical methodology is presented to characterise the performance of the scrubber by varying several factors such as gas pollutant concentration, air flowrate and absorbing solution flowrate. Some types of venturi tube constructions were assessed, including the use of a two-stage venturi tube. The results showed a strong influence of the liquid scrubbing flowrate on pollutant removal efficiency. The initial pollutant concentration and the gas flowrate had a slight influence. The use of a two-stage venturi tube considerably improved the absorption efficiency, although it increased energy consumption. The results of this study will be applicable to the optimal design of venturi-based absorbers for gaseous pollution control or chemical reactors.

The efficacy of single-stage open intramedullary nailing of neglected femur fractures.

Science.gov (United States)

Boopalan, P R J V C; Sait, Azad; Jepegnanam, Thilak Samuel; Matthai, Thomas; Varghese, Viju Daniel

2014-02-01

Neglected femur fractures are not rare in the developing world. Treatment options include single-stage open reduction and intramedullary nailing, or open release, skeletal traction, and then second-stage open intramedullary nailing, with bone grafting. Single-stage procedures have the potential advantage of avoiding neurovascular complications secondary to acute lengthening, but they require a second operation, with potentially increased resource use and infection risk. We sought to determine the (1) likelihood of union, (2) complications and reoperations, and (3) functional results with single-stage open intramedullary nailing without bone grafting in patients with neglected femur fractures. Between January 2003 and December 2007, 17 consecutive patients presented to our practice with neglected femoral shaft fractures. All were treated with single-stage nailing without bone grafting. There were 15 men and two women with a median age of 27 years. The average time from fracture to treatment was 13 weeks (range, 4-44 weeks). Eleven patients underwent open nailing with interlocked nails and six were treated with cloverleaf Kuntscher nails. Patients were followed for a minimum of 6 months (mean, 33 months; range, 6-72 months). The mean preoperative ROM of the knee was 28° (range, 10°-150°) and femoral length discrepancy was 3.1 cm (range, 1-5 cm). All fractures united and the mean time to union was 16 weeks (range, 7-32 weeks). There were no neurologic complications secondary to acute lengthening. The mean postoperative ROM of the knee was 130° (range, 60°-150°). All patients were able to return to preinjury work. Sixteen patients regained their original femoral length. One-stage open intramedullary nailing of neglected femoral diaphyseal fractures without bone grafting was safe and effective, and obviated the need for a two-stage approach. Although the findings need to be replicated in larger numbers of patients, we believe this technique may be useful in

Two-Stage Power Factor Corrected Power Supplies: The Low Component-Stress Approach

DEFF Research Database (Denmark)

Petersen, Lars; Andersen, Michael Andreas E.

2002-01-01

The discussion concerning the use of single-stage contra two-stage PFC solutions has been going on for the last decade and it continues. The purpose of this paper is to direct the focus back on how the power is processed and not so much as to the number of stages or the amount of power processed...

Mass-transfer in extraction and reextraction as a single-stage process

International Nuclear Information System (INIS)

Rodriguez del Cerro, M.; Trilleros, J.A.; Otero de la Gandara, J.L.

1987-01-01

The rate of mass transfer between water and naftenic acid and threebutilphosphate in kerosen are studied in the two possibilities to or from water. The two insoluble phases are brought in to intimate contact with dispersed phase droplets, in a single-stage process. The evolution of the equilibrium distribution of solute is taken in consideration. (author)

A method for determining optimum phasing of a multiphase propulsion system for a single-stage vehicle with linearized inert weight

Science.gov (United States)

Martin, J. A.

1974-01-01

A general analytical treatment is presented of a single-stage vehicle with multiple propulsion phases. A closed-form solution for the cost and for the performance and a derivation of the optimal phasing of the propulsion are included. Linearized variations in the inert weight elements are included, and the function to be minimized can be selected. The derivation of optimal phasing results in a set of nonlinear algebraic equations for optimal fuel volumes, for which a solution method is outlined. Three specific example cases are analyzed: minimum gross lift-off weight, minimum inert weight, and a minimized general function for a two-phase vehicle. The results for the two-phase vehicle are applied to the dual-fuel rocket. Comparisons with single-fuel vehicles indicate that dual-fuel vehicles can have lower inert weight either by development of a dual-fuel engine or by parallel burning of separate engines from lift-off.

Metabolic tumour volumes measured at staging in lymphoma: methodological evaluation on phantom experiments and patients

Energy Technology Data Exchange (ETDEWEB)

Meignan, Michel [Hopital Henri Mondor and Paris-Est University, Department of Nuclear Medicine, Creteil (France); Paris-Est University, Service de Medecine Nucleaire, EAC CNRS 7054, Hopital Henri Mondor AP-HP, Creteil (France); Sasanelli, Myriam; Itti, Emmanuel [Hopital Henri Mondor and Paris-Est University, Department of Nuclear Medicine, Creteil (France); Casasnovas, Rene Olivier [CHU Le Bocage, Department of Hematology, Dijon (France); Luminari, Stefano [University of Modena and Reggio Emilia, Department of Diagnostic, Clinic and Public Health Medicine, Modena (Italy); Fioroni, Federica [Santa Maria Nuova Hospital-IRCCS, Department of Medical Physics, Reggio Emilia (Italy); Coriani, Chiara [Santa Maria Nuova Hospital-IRCCS, Department of Radiology, Reggio Emilia (Italy); Masset, Helene [Henri Mondor Hospital, Department of Radiophysics, Creteil (France); Gobbi, Paolo G. [University of Pavia, Department of Internal Medicine and Gastroenterology, Fondazione IRCCS Policlinico San Matteo, Pavia (Italy); Merli, Francesco [Santa Maria Nuova Hospital-IRCCS, Department of Hematology, Reggio Emilia (Italy); Versari, Annibale [Santa Maria Nuova Hospital-IRCCS, Department of Nuclear Medicine, Reggio Emilia (Italy)

2014-06-15

The presence of a bulky tumour at staging on CT is an independent prognostic factor in malignant lymphomas. However, its prognostic value is limited in diffuse disease. Total metabolic tumour volume (TMTV) determined on {sup 18}F-FDG PET/CT could give a better evaluation of the total tumour burden and may help patient stratification. Different methods of TMTV measurement established in phantoms simulating lymphoma tumours were investigated and validated in 40 patients with Hodgkin lymphoma and diffuse large B-cell lymphoma. Data were processed by two nuclear medicine physicians in Reggio Emilia and Creteil. Nineteen phantoms filled with {sup 18}F-saline were scanned; these comprised spherical or irregular volumes from 0.5 to 650 cm{sup 3} with tumour-to-background ratios from 1.65 to 40. Volumes were measured with different SUVmax thresholds. In patients, TMTV was measured on PET at staging by two methods: volumes of individual lesions were measured using a fixed 41 % SUVmax threshold (TMTV{sub 41}) and a variable visually adjusted SUVmax threshold (TMTV{sub var}). In phantoms, the 41 % threshold gave the best concordance between measured and actual volumes. Interobserver agreement was almost perfect. In patients, the agreement between the reviewers for TMTV{sub 41} measurement was substantial (ρ {sub c} = 0.986, CI 0.97 - 0.99) and the difference between the means was not significant (212 ± 218 cm{sup 3} for Creteil vs. 206 ± 219 cm{sup 3} for Reggio Emilia, P = 0.65). By contrast the agreement was poor for TMTV{sub var}. There was a significant direct correlation between TMTV{sub 41} and normalized LDH (r = 0.652, CI 0.42 - 0.8, P <0.001). Higher disease stages and bulky tumour were associated with higher TMTV{sub 41}, but high TMTV{sub 41} could be found in patients with stage 1/2 or nonbulky tumour. Measurement of baseline TMTV in lymphoma using a fixed 41% SUVmax threshold is reproducible and correlates with the other parameters for tumour mass evaluation

Tissue Expansion Using Hyaluronic Acid Filler for Single-Stage Ear Reconstruction: A Novel Concept for Difficult Areas.

Science.gov (United States)

Inbal, Amir; Lemelman, Benjamin T; Millet, Eran; Greensmith, Andrew

2017-10-16

Auricular reconstruction is one of the most challenging procedures in plastic surgery. An adequate skin envelope is essential for cartilage framework coverage, yet few good options exist without additional surgery. We propose a novel method for minimally invasive tissue expansion, using hyaluronic acid (HA) filler to allow for single-stage ear reconstruction. To introduce the novel concept of HA filler for tissue expansion in ear reconstruction, and as an alternative to traditional expansion techniques. Macrolane is a large particle HA gel developed for large volume restoration. Expansion of the non-hair-bearing mastoid skin was performed in our clinic weekly or every other week. Final expansion was completed one week prior to reconstructive surgery. Tissue from one patient's expanded pocket was sent for histological analysis. Ten patients underwent single-stage auricular reconstruction with preoperative expansion. Injection sessions ranged from 7 to 13 (mean, 9.7). Mean injected volume per session was 2.03 mL per patient, for an average total of 19.8 mL (range, 14.5-30 mL). There were no major complications. One minor complication required removal of exposed wire from the antihelix in the office. Hematoxylin and eosin stain revealed similar histology to that seen with traditional expanders. This novel expansion technique using serial HA injections allowed for optimized skin coverage in single-stage ear reconstruction. The concept of tissue expansion using HA filler is a new frontier for research that may be applicable to other arenas of reconstruction. 4. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

Design of single piece sabot for a single stage gas gun

Science.gov (United States)

Vemparala, Vignesh; Mathew, Arun Tom; Rao Koka, Tirumala

2017-11-01

Single piece sabot is a vital part in single stage gas guns for impact testing in aerospace industries. Depending on the type of projectile used the design of sabot varies to accommodate the testing equipment. The velocity of the projectile exiting the barrel is dependent on the material and shape of the sabot used. The material selected for the design of sabot is rigid polyurethane foam, due to their low elastic modulus and low density. Two samples of rigid PU foam is taken and tests are performed to get their exact material properties. These properties are incorporated in numerical simulation to determine the best fit for practical use. Since the PU foams has a wide range of porosity which plays a prominent role in deciding the exit velocity and accuracy of the projectile coming out of the barrel. By optimisation, to the best suitable material sample can be determined.

One-stage and two-stage penile buccal mucosa urethroplasty

Directory of Open Access Journals (Sweden)

G. Barbagli

2016-03-01

Full Text Available The paper provides the reader with the detailed description of current techniques of one-stage and two-stage penile buccal mucosa urethroplasty. The paper provides the reader with the preoperative patient evaluation paying attention to the use of diagnostic tools. The one-stage penile urethroplasty using buccal mucosa graft with the application of glue is preliminary showed and discussed. Two-stage penile urethroplasty is then reported. A detailed description of first-stage urethroplasty according Johanson technique is reported. A second-stage urethroplasty using buccal mucosa graft and glue is presented. Finally postoperative course and follow-up are addressed.

A Finite-Volume approach for compressible single- and two-phase flows in flexible pipelines with fluid-structure interaction

Science.gov (United States)

Daude, F.; Galon, P.

2018-06-01

A Finite-Volume scheme for the numerical computations of compressible single- and two-phase flows in flexible pipelines is proposed based on an approximate Godunov-type approach. The spatial discretization is here obtained using the HLLC scheme. In addition, the numerical treatment of abrupt changes in area and network including several pipelines connected at junctions is also considered. The proposed approach is based on the integral form of the governing equations making it possible to tackle general equations of state. A coupled approach for the resolution of fluid-structure interaction of compressible fluid flowing in flexible pipes is considered. The structural problem is solved using Euler-Bernoulli beam finite elements. The present Finite-Volume method is applied to ideal gas and two-phase steam-water based on the Homogeneous Equilibrium Model (HEM) in conjunction with a tabulated equation of state in order to demonstrate its ability to tackle general equations of state. The extensive application of the scheme for both shock tube and other transient flow problems demonstrates its capability to resolve such problems accurately and robustly. Finally, the proposed 1-D fluid-structure interaction model appears to be computationally efficient.

Treatment of corn ethanol distillery wastewater using two-stage anaerobic digestion.

Science.gov (United States)

Ráduly, B; Gyenge, L; Szilveszter, Sz; Kedves, A; Crognale, S

In this study the mesophilic two-stage anaerobic digestion (AD) of corn bioethanol distillery wastewater is investigated in laboratory-scale reactors. Two-stage AD technology separates the different sub-processes of the AD in two distinct reactors, enabling the use of optimal conditions for the different microbial consortia involved in the different process phases, and thus allowing for higher applicable organic loading rates (OLRs), shorter hydraulic retention times (HRTs) and better conversion rates of the organic matter, as well as higher methane content of the produced biogas. In our experiments the reactors have been operated in semi-continuous phase-separated mode. A specific methane production of 1,092 mL/(L·d) has been reached at an OLR of 6.5 g TCOD/(L·d) (TCOD: total chemical oxygen demand) and a total HRT of 21 days (5.7 days in the first-stage, and 15.3 days in the second-stage reactor). Nonetheless the methane concentration in the second-stage reactor was very high (78.9%); the two-stage AD outperformed the reference single-stage AD (conducted at the same reactor loading rate and retention time) by only a small margin in terms of volumetric methane production rate. This makes questionable whether the higher methane content of the biogas counterbalances the added complexity of the two-stage digestion.

Measurement of the volume growth rate of single budding yeast with the MOSFET-based microfluidic Coulter counter.

Science.gov (United States)

Sun, Jiashu; Stowers, Chris C; Boczko, Erik M; Li, Deyu

2010-11-07

We report on measurements of the volume growth rate of ten individual budding yeast cells using a recently developed MOSFET-based microfluidic Coulter counter. The MOSFET-based microfluidic Coulter counter is very sensitive, provides signals that are immune from the baseline drift, and can work with cell culture media of complex composition. These desirable features allow us to directly measure the volume growth rate of single cells of Saccharomyces cerevisiae LYH3865 strain budding yeast in YNB culture media over a whole cell cycle. Results indicate that all budding yeast follow a sigmoid volume growth profile with reduced growth rates at the initial stage before the bud emerges and the final stage after the daughter gets mature. Analysis of the data indicates that even though all piecewise linear, Gomperitz, and Hill's function models can fit the global growth profile equally well, the data strongly support local exponential growth phenomenon. Accurate volume growth measurements are important for applications in systems biology where quantitative parameters are required for modeling and simulation.

Comparison of two-stage thermophilic (68 degrees C/55 degrees C) anaerobic digestion with one-stage thermophilic (55 degrees C) digestion of cattle manure

DEFF Research Database (Denmark)

Nielsen, H.B.; Mladenovska, Zuzana; Westermann, Peter

2004-01-01

A two-stage 68degreesC/55degreesC anaerobic degradation process for treatment of cattle manure was studied. In batch experiments, an increase of the specific methane yield, ranging from 24% to 56%, was obtained when cattle manure and its fractions (fibers and liquid) were pretreated at 68degrees......, was compared with a conventional single-stage reactor running at 55degreesC with 15-days HRT. When an organic loading of 3 g volatile solids (VS) per liter per day was applied, the two-stage setup had a 6% to 8% higher specific methane yield and a 9% more effective VS-removal than the conventional single......-stage reactor. The 68degreesC reactor generated 7% to 9% of the total amount of methane of the two-stage system and maintained a volatile fatty acids (VFA) concentration of 4.0 to 4.4 g acetate per liter. Population size and activity of aceticlastic methanogens, syntrophic bacteria, and hydrolytic...

Possible two-stage 87Sr evolution in the Stockdale Rhyolite

International Nuclear Information System (INIS)

Compston, W.; McDougall, I.; Wyborn, D.

1982-01-01

The Rb-Sr total-rock data for the Stockdale Rhyolite, of significance for the Palaeozoic time scale, are more scattered about a single-stage isochron than expected from experimental error. Two-stage 87 Sr evolution for several of the samples is explored to explain this, as an alternative to variation in the initial 87 Sr/ 86 Sr which is customarily used in single-stage dating models. The deletion of certain samples having very high Rb/Sr removes most of the excess scatter and leads to an estimate of 430 +- 7 m.y. for the age of extrusion. There is a younger alignment of Rb-Sr data within each sampling site at 412 +- 7 m.y. We suggest that the Stockdale Rhyolite is at least 430 m.y. old, that its original range in Rb/Sr was smaller than now observed, and that it experienced a net loss in Sr during later hydrothermal alteration at ca. 412 m.y. (orig.)

A two-stage heating scheme for heat assisted magnetic recording

Science.gov (United States)

Xiong, Shaomin; Kim, Jeongmin; Wang, Yuan; Zhang, Xiang; Bogy, David

2014-05-01

Heat Assisted Magnetic Recording (HAMR) has been proposed to extend the storage areal density beyond 1 Tb/in.2 for the next generation magnetic storage. A near field transducer (NFT) is widely used in HAMR systems to locally heat the magnetic disk during the writing process. However, much of the laser power is absorbed around the NFT, which causes overheating of the NFT and reduces its reliability. In this work, a two-stage heating scheme is proposed to reduce the thermal load by separating the NFT heating process into two individual heating stages from an optical waveguide and a NFT, respectively. As the first stage, the optical waveguide is placed in front of the NFT and delivers part of laser energy directly onto the disk surface to heat it up to a peak temperature somewhat lower than the Curie temperature of the magnetic material. Then, the NFT works as the second heating stage to heat a smaller area inside the waveguide heated area further to reach the Curie point. The energy applied to the NFT in the second heating stage is reduced compared with a typical single stage NFT heating system. With this reduced thermal load to the NFT by the two-stage heating scheme, the lifetime of the NFT can be extended orders longer under the cyclic load condition.

CFD modeling of two-stage ignition in a rapid compression machine: Assessment of zero-dimensional approach

Energy Technology Data Exchange (ETDEWEB)

Mittal, Gaurav [Department of Mechanical Engineering, The University of Akron, Akron, OH 44325 (United States); Raju, Mandhapati P. [General Motor R and D Tech Center, Warren, MI 48090 (United States); Sung, Chih-Jen [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269 (United States)

2010-07-15

In modeling rapid compression machine (RCM) experiments, zero-dimensional approach is commonly used along with an associated heat loss model. The adequacy of such approach has not been validated for hydrocarbon fuels. The existence of multi-dimensional effects inside an RCM due to the boundary layer, roll-up vortex, non-uniform heat release, and piston crevice could result in deviation from the zero-dimensional assumption, particularly for hydrocarbons exhibiting two-stage ignition and strong thermokinetic interactions. The objective of this investigation is to assess the adequacy of zero-dimensional approach in modeling RCM experiments under conditions of two-stage ignition and negative temperature coefficient (NTC) response. Computational fluid dynamics simulations are conducted for n-heptane ignition in an RCM and the validity of zero-dimensional approach is assessed through comparisons over the entire NTC region. Results show that the zero-dimensional model based on the approach of 'adiabatic volume expansion' performs very well in adequately predicting the first-stage ignition delays, although quantitative discrepancy for the prediction of the total ignition delays and pressure rise in the first-stage ignition is noted even when the roll-up vortex is suppressed and a well-defined homogeneous core is retained within an RCM. Furthermore, the discrepancy is pressure dependent and decreases as compressed pressure is increased. Also, as ignition response becomes single-stage at higher compressed temperatures, discrepancy from the zero-dimensional simulations reduces. Despite of some quantitative discrepancy, the zero-dimensional modeling approach is deemed satisfactory from the viewpoint of the ignition delay simulation. (author)

Optics of two-stage photovoltaic concentrators with dielectric second stages

Science.gov (United States)

Ning, Xiaohui; O'Gallagher, Joseph; Winston, Roland

1987-04-01

Two-stage photovoltaic concentrators with Fresnel lenses as primaries and dielectric totally internally reflecting nonimaging concentrators as secondaries are discussed. The general design principles of such two-stage systems are given. Their optical properties are studied and analyzed in detail using computer ray trace procedures. It is found that the two-stage concentrator offers not only a higher concentration or increased acceptance angle, but also a more uniform flux distribution on the photovoltaic cell than the point focusing Fresnel lens alone. Experimental measurements with a two-stage prototype module are presented and compared to the analytical predictions.

Optics of two-stage photovoltaic concentrators with dielectric second stages.

Science.gov (United States)

Ning, X; O'Gallagher, J; Winston, R

1987-04-01

Two-stage photovoltaic concentrators with Fresnel lenses as primaries and dielectric totally internally reflecting nonimaging concentrators as secondaries are discussed. The general design principles of such two-stage systems are given. Their optical properties are studied and analyzed in detail using computer ray trace procedures. It is found that the two-stage concentrator offers not only a higher concentration or increased acceptance angle, but also a more uniform flux distribution on the photovoltaic cell than the point focusing Fresnel lens alone. Experimental measurements with a two-stage prototype module are presented and compared to the analytical predictions.

Recording single neurons' action potentials from freely moving pigeons across three stages of learning.

Science.gov (United States)

Starosta, Sarah; Stüttgen, Maik C; Güntürkün, Onur

2014-06-02

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed single-neuron activity while animals are acquiring an operantly conditioned response, or when that response is extinguished. But even in these cases, observation periods usually encompass only a single stage of learning, i.e. acquisition or extinction, but not both (exceptions include protocols employing reversal learning; see Bingman et al.(1) for an example). However, acquisition and extinction entail different learning mechanisms and are therefore expected to be accompanied by different types and/or loci of neural plasticity. Accordingly, we developed a behavioral paradigm which institutes three stages of learning in a single behavioral session and which is well suited for the simultaneous recording of single neurons' action potentials. Animals are trained on a single-interval forced choice task which requires mapping each of two possible choice responses to the presentation of different novel visual stimuli (acquisition). After having reached a predefined performance criterion, one of the two choice responses is no longer reinforced (extinction). Following a certain decrement in performance level, correct responses are reinforced again (reacquisition). By using a new set of stimuli in every session, animals can undergo the acquisition-extinction-reacquisition process repeatedly. Because all three stages of learning occur in a single behavioral session, the paradigm is ideal for the simultaneous observation of the spiking output of multiple single neurons. We use pigeons as model systems, but the task can easily be adapted to any other species capable of conditioned discrimination learning.

Preoperative Single Fraction Partial Breast Radiotherapy for Early-Stage Breast Cancer

Energy Technology Data Exchange (ETDEWEB)

Palta, Manisha; Yoo, Sua; Adamson, Justus D.; Prosnitz, Leonard R. [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Horton, Janet K., E-mail: janet.horton@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States)

2012-01-01

Purpose: Several recent series evaluating external beam accelerated partial breast irradiation (PBI) have reported adverse cosmetic outcomes, possibly related to large volumes of normal tissue receiving near-prescription doses. We hypothesized that delivery of external beam PBI in a single fraction to the preoperative tumor volume would be feasible and result in a decreased dose to the uninvolved breast compared with institutional postoperative PBI historical controls. Methods and Materials: A total of 17 patients with unifocal Stage T1 breast cancer were identified. Contrast-enhanced subtraction magnetic resonance images were loaded into an Eclipse treatment planning system and used to define the target volumes. A 'virtual plan' was created using four photon beams in a noncoplanar beam arrangement and optimized to deliver 15 Gy to the planning target volume. Results: The median breast volume was 1,713 cm{sup 3} (range: 1,014-2,140), and the median clinical target volume was 44 cm{sup 3} (range: 26-73). In all cases, 100% of the prescription dose covered 95% of the clinical target volume. The median conformity index was 0.86 (range: 0.70-1.12). The median percentage of the ipsilateral breast volume receiving 100% and 50% of the prescribed dose was 3.8% (range: 2.2-6.9) and 13.3% (range: 7.5-20.8) compared with 18% (range: 3-42) and 53% (range: 24-65) in the institutional historical controls treated with postoperative external beam PBI (p = .002). The median maximum skin dose was 9 Gy. The median dose to 1 and 10 cm{sup 3} of skin was 6.7 and 4.9 Gy. The doses to the heart and ipsilateral lung were negligible. Conclusion: Preoperative PBI resulted in a substantial reduction in ipsilateral breast tissue dose compared with postoperative PBI. The skin dose appeared reasonable, given the small volumes. A prospective Phase I trial evaluating this technique is ongoing.

Preoperative single fraction partial breast radiotherapy for early-stage breast cancer.

Science.gov (United States)

Palta, Manisha; Yoo, Sua; Adamson, Justus D; Prosnitz, Leonard R; Horton, Janet K

2012-01-01

Several recent series evaluating external beam accelerated partial breast irradiation (PBI) have reported adverse cosmetic outcomes, possibly related to large volumes of normal tissue receiving near-prescription doses. We hypothesized that delivery of external beam PBI in a single fraction to the preoperative tumor volume would be feasible and result in a decreased dose to the uninvolved breast compared with institutional postoperative PBI historical controls. A total of 17 patients with unifocal Stage T1 breast cancer were identified. Contrast-enhanced subtraction magnetic resonance images were loaded into an Eclipse treatment planning system and used to define the target volumes. A "virtual plan" was created using four photon beams in a noncoplanar beam arrangement and optimized to deliver 15 Gy to the planning target volume. The median breast volume was 1,713 cm(3) (range: 1,014-2,140), and the median clinical target volume was 44 cm(3) (range: 26-73). In all cases, 100% of the prescription dose covered 95% of the clinical target volume. The median conformity index was 0.86 (range: 0.70-1.12). The median percentage of the ipsilateral breast volume receiving 100% and 50% of the prescribed dose was 3.8% (range: 2.2-6.9) and 13.3% (range: 7.5-20.8) compared with 18% (range: 3-42) and 53% (range: 24-65) in the institutional historical controls treated with postoperative external beam PBI (p = .002). The median maximum skin dose was 9 Gy. The median dose to 1 and 10 cm(3) of skin was 6.7 and 4.9 Gy. The doses to the heart and ipsilateral lung were negligible. Preoperative PBI resulted in a substantial reduction in ipsilateral breast tissue dose compared with postoperative PBI. The skin dose appeared reasonable, given the small volumes. A prospective Phase I trial evaluating this technique is ongoing. Copyright © 2012 Elsevier Inc. All rights reserved.

Preoperative Single Fraction Partial Breast Radiotherapy for Early-Stage Breast Cancer

International Nuclear Information System (INIS)

Palta, Manisha; Yoo, Sua; Adamson, Justus D.; Prosnitz, Leonard R.; Horton, Janet K.

2012-01-01

Purpose: Several recent series evaluating external beam accelerated partial breast irradiation (PBI) have reported adverse cosmetic outcomes, possibly related to large volumes of normal tissue receiving near-prescription doses. We hypothesized that delivery of external beam PBI in a single fraction to the preoperative tumor volume would be feasible and result in a decreased dose to the uninvolved breast compared with institutional postoperative PBI historical controls. Methods and Materials: A total of 17 patients with unifocal Stage T1 breast cancer were identified. Contrast-enhanced subtraction magnetic resonance images were loaded into an Eclipse treatment planning system and used to define the target volumes. A “virtual plan” was created using four photon beams in a noncoplanar beam arrangement and optimized to deliver 15 Gy to the planning target volume. Results: The median breast volume was 1,713 cm 3 (range: 1,014–2,140), and the median clinical target volume was 44 cm 3 (range: 26–73). In all cases, 100% of the prescription dose covered 95% of the clinical target volume. The median conformity index was 0.86 (range: 0.70–1.12). The median percentage of the ipsilateral breast volume receiving 100% and 50% of the prescribed dose was 3.8% (range: 2.2–6.9) and 13.3% (range: 7.5–20.8) compared with 18% (range: 3–42) and 53% (range: 24–65) in the institutional historical controls treated with postoperative external beam PBI (p = .002). The median maximum skin dose was 9 Gy. The median dose to 1 and 10 cm 3 of skin was 6.7 and 4.9 Gy. The doses to the heart and ipsilateral lung were negligible. Conclusion: Preoperative PBI resulted in a substantial reduction in ipsilateral breast tissue dose compared with postoperative PBI. The skin dose appeared reasonable, given the small volumes. A prospective Phase I trial evaluating this technique is ongoing.

The experimental study of a two-stage photovoltaic thermal system based on solar trough concentration

International Nuclear Information System (INIS)

Tan, Lijun; Ji, Xu; Li, Ming; Leng, Congbin; Luo, Xi; Li, Haili

2014-01-01

Highlights: • A two-stage photovoltaic thermal system based on solar trough concentration. • Maximum cell efficiency of 5.21% with the mirror opening width of 57 cm. • With single cycle, maximum temperatures rise in the heating stage is 12.06 °C. • With 30 min multiple cycles, working medium temperature 62.8 °C, increased 28.7 °C. - Abstract: A two-stage photovoltaic thermal system based on solar trough concentration is proposed, in which the metal cavity heating stage is added on the basis of the PV/T stage, and thermal energy with higher temperature is output while electric energy is output. With the 1.8 m 2 mirror PV/T system, the characteristic parameters of the space solar cell under non-concentrating solar radiation and concentrating solar radiation are respectively tested experimentally, and the solar cell output characteristics at different opening widths of concentrating mirror of the PV/T stage under condensation are also tested experimentally. When the mirror opening width was 57 cm, the solar cell efficiency reached maximum value of 5.21%. The experimental platform of the two-stage photovoltaic thermal system was established, with a 1.8 m 2 mirror PV/T stage and a 15 m 2 mirror heating stage, or a 1.8 m 2 mirror PV/T stage and a 30 m 2 mirror heating stage. The results showed that with single cycle, the long metal cavity heating stage would bring lower thermal efficiency, but temperature rise of the working medium is higher, up to 12.06 °C with only single cycle. With 30 min closed multiple cycles, the temperature of the working medium in the water tank was 62.8 °C, with an increase of 28.7 °C, and thermal energy with higher temperature could be output

Influence of capacity- and time-constrained intermediate storage in two-stage food production systems

DEFF Research Database (Denmark)

Akkerman, Renzo; van Donk, Dirk Pieter; Gaalman, Gerard

2007-01-01

In food processing, two-stage production systems with a batch processor in the first stage and packaging lines in the second stage are common and mostly separated by capacity- and time-constrained intermediate storage. This combination of constraints is common in practice, but the literature hardly...... of systems like this. Contrary to the common sense in operations management, the LPT rule is able to maximize the total production volume per day. Furthermore, we show that adding one tank has considerable effects. Finally, we conclude that the optimal setup frequency for batches in the first stage...... pays any attention to this. In this paper, we show how various capacity and time constraints influence the performance of a specific two-stage system. We study the effects of several basic scheduling and sequencing rules in the presence of these constraints in order to learn the characteristics...

Metabolic tumour volumes measured at staging in lymphoma: methodological evaluation on phantom experiments and patients

International Nuclear Information System (INIS)

Meignan, Michel; Sasanelli, Myriam; Itti, Emmanuel; Casasnovas, Rene Olivier; Luminari, Stefano; Fioroni, Federica; Coriani, Chiara; Masset, Helene; Gobbi, Paolo G.; Merli, Francesco; Versari, Annibale

2014-01-01

The presence of a bulky tumour at staging on CT is an independent prognostic factor in malignant lymphomas. However, its prognostic value is limited in diffuse disease. Total metabolic tumour volume (TMTV) determined on 18 F-FDG PET/CT could give a better evaluation of the total tumour burden and may help patient stratification. Different methods of TMTV measurement established in phantoms simulating lymphoma tumours were investigated and validated in 40 patients with Hodgkin lymphoma and diffuse large B-cell lymphoma. Data were processed by two nuclear medicine physicians in Reggio Emilia and Creteil. Nineteen phantoms filled with 18 F-saline were scanned; these comprised spherical or irregular volumes from 0.5 to 650 cm 3 with tumour-to-background ratios from 1.65 to 40. Volumes were measured with different SUVmax thresholds. In patients, TMTV was measured on PET at staging by two methods: volumes of individual lesions were measured using a fixed 41 % SUVmax threshold (TMTV 41 ) and a variable visually adjusted SUVmax threshold (TMTV var ). In phantoms, the 41 % threshold gave the best concordance between measured and actual volumes. Interobserver agreement was almost perfect. In patients, the agreement between the reviewers for TMTV 41 measurement was substantial (ρ c = 0.986, CI 0.97 - 0.99) and the difference between the means was not significant (212 ± 218 cm 3 for Creteil vs. 206 ± 219 cm 3 for Reggio Emilia, P = 0.65). By contrast the agreement was poor for TMTV var . There was a significant direct correlation between TMTV 41 and normalized LDH (r = 0.652, CI 0.42 - 0.8, P 41 , but high TMTV 41 could be found in patients with stage 1/2 or nonbulky tumour. Measurement of baseline TMTV in lymphoma using a fixed 41% SUVmax threshold is reproducible and correlates with the other parameters for tumour mass evaluation. It should be evaluated in prospective studies. (orig.)

Evaluation of left ventricular function and volumes in patients with ischaemic cardiomyopathy: gated single-photon emission computed tomography versus two-dimensional echocardiography

International Nuclear Information System (INIS)

Vourvouri, E.C.; Poldermans, D.; Sianos, G.; Sozzi, F.B.; Schinkel, A.F.L.; Sutter, J. de; Roelandt, J.R.T.C.; Bax, J.J.; Parcharidis, G.; Valkema, R.

2001-01-01

The objective of this study was to perform a head-to-head comparison between two-dimensional (2D) echocardiography and gated single-photon emission computed tomography (SPET) for the evaluation of left ventricular (LV) function and volumes in patients with severe ischaemic LV dysfunction. Thirty-two patients with chronic ischaemic LV dysfunction [mean LV ejection fraction (EF) 25%±6%] were studied with gated SPET and 2D echocardiography. Regional wall motion was evaluated by both modalities and scored by two independent observers using a 16-segment model with a 5-point scoring system (1= normokinesia, 2= mild hypokinesia, 3= severe hypokinesia, 4= akinesia and 5= dyskinesia). LVEF and LV end-diastolic and end-systolic volumes were evaluated by 2D echocardiography using the Simpson's biplane discs method. The same parameters were calculated using quantitative gated SPET software (QGS, Cedars-Sinai Medical Center). The overall agreement between the two imaging modalities for assessment of regional wall motion was 69%. The correlations between gated SPET and 2D echocardiography for the assessment of end-diastolic and end-systolic volumes were excellent (r=0.94, P<0.01, and r=0.96, P<0.01, respectively). The correlation for LVEF was also good (r=0.83, P<0.01). In conclusion: in patients with ischaemic cardiomyopathy, close and significant relations between gated SPET and 2D echocardiography were observed for the assessment of regional and global LV function and LV volumes; gated SPET has the advantage that it provides information on both LV function/dimensions and perfusion. (orig.)

Application of two-stage biofilter system for the removal of odorous compounds.

Science.gov (United States)

Jeong, Gwi-Taek; Park, Don-Hee; Lee, Gwang-Yeon; Cha, Jin-Myeong

2006-01-01

Biofiltration is a biological process which is considered to be one of the more successful examples of biotechnological applications to environmental engineering, and is most commonly used in the removal of odoriferous compounds. In this study, we have attempted to assess the efficiency with which both single and complex odoriferous compounds could be removed, using one- or two-stage biofiltration systems. The tested single odor gases, limonene, alpha-pinene, and iso-butyl alcohol, were separately evaluated in the biofilters. Both limonene and alpha-pinene were removed by 90% or more EC (elimination capacity), 364 g/m3/h and 321 g/m3/h, respectively, at an input concentration of 50 ppm and a retention time of 30 s. The iso-butyl alcohol was maintained with an effective removal yield of more than 90% (EC 375 g/m3/h) at an input concentration of 100 ppm. The complex gas removal scheme was applied with a 200 ppm inlet concentration of ethanol, 70 ppm of acetaldehyde, and 70 ppm of toluene with residence time of 45 s in a one- or two-stage biofiltration system. The removal yield of toluene was determined to be lower than that of the other gases in the one-stage biofilter. Otherwise, the complex gases were sufficiently eliminated by the two-stage biofiltration system.

design, construction and measured performance of a single-stage

African Journals Online (AJOL)

2012-11-03

Nov 3, 2012 ... Abstract. The design philosophy, construction and measured performances of a single stage, single entry centrifugal pump .... the tachometer spindle to be held against a recess in the motor shaft. The constructed centrifugal ...

Possible two-stage /sup 87/Sr evolution in the Stockdale Rhyolite

Energy Technology Data Exchange (ETDEWEB)

Compston, W.; McDougall, I. (Australian National Univ., Canberra. Research School of Earth Sciences); Wyborn, D. (Department of Minerals and Energy, Canberra (Australia). Bureau of Mineral Resources)

1982-12-01

The Rb-Sr total-rock data for the Stockdale Rhyolite, of significance for the Palaeozoic time scale, are more scattered about a single-stage isochron than expected from experimental error. Two-stage /sup 87/Sr evolution for several of the samples is explored to explain this, as an alternative to variation in the initial /sup 87/Sr//sup 86/Sr which is customarily used in single-stage dating models. The deletion of certain samples having very high Rb/Sr removes most of the excess scatter and leads to an estimate of 430 +- 7 m.y. for the age of extrusion. There is a younger alignment of Rb-Sr data within each sampling site at 412 +- 7 m.y. We suggest that the Stockdale Rhyolite is at least 430 m.y. old, that its original range in Rb/Sr was smaller than now observed, and that it experienced a net loss in Sr during later hydrothermal alteration at ca. 412 m.y.

Multiple kernel learning using single stage function approximation for binary classification problems

Science.gov (United States)

Shiju, S.; Sumitra, S.

2017-12-01

In this paper, the multiple kernel learning (MKL) is formulated as a supervised classification problem. We dealt with binary classification data and hence the data modelling problem involves the computation of two decision boundaries of which one related with that of kernel learning and the other with that of input data. In our approach, they are found with the aid of a single cost function by constructing a global reproducing kernel Hilbert space (RKHS) as the direct sum of the RKHSs corresponding to the decision boundaries of kernel learning and input data and searching that function from the global RKHS, which can be represented as the direct sum of the decision boundaries under consideration. In our experimental analysis, the proposed model had shown superior performance in comparison with that of existing two stage function approximation formulation of MKL, where the decision functions of kernel learning and input data are found separately using two different cost functions. This is due to the fact that single stage representation helps the knowledge transfer between the computation procedures for finding the decision boundaries of kernel learning and input data, which inturn boosts the generalisation capacity of the model.

Single-staged uniportal VATS in the supine position for simultaneous bilateral primary spontaneous pneumothorax.

Science.gov (United States)

Kim, Kyung Soo

2017-05-15

Simultaneous bilateral primary spontaneous pneumothorax (SBPSP) is rare, but requires surgery on both sides, in patients with definite bilateral bullae to prevent life-threatening conditions. Recently, uniportal video-assisted thoracoscopic surgery (VATS) has been widely accepted as a less invasive technique for the treatment of pneumothorax. Thus, we introduced single-staged uniportal VATS technique in the supine position, for the management of two cases of SBPSP. A 17-year-old boy presented with bilateral spontaneous pneumothorax and he underwent single-staged uniportal VATS in the supine position. Single wide draping in consecutive bilateral approaches removes the needs of changing patients' position. Whole thoracoscopic procedure for wedge resection of bullae lesions was conducted without difficulty. The total operation time took 65 min and the patient discharged 3 days after the operation. The patient was followed for 24 months without recurrence of both sides. Another 18-year-old boy was admitted with bilateral spontaneous pneumothorax and single-staged uniportal VATS was also performed in the supine position. The total operation time took 79 min and the patient discharged on postoperative day 4. He was followed for 19 months without recurrence of both sides. Single-staged uniportal VATS approach yielded satisfactory results from simplicity that not requires position change compared to conventional multi-ports VATS in the lateral position, and with better cosmetics. This technique is thought to be a feasible procedure in selective patients with SBPSP or with contralateral bullae for preventive role.

Adaptive kanban control mechanism for a single-stage hybrid system

Science.gov (United States)

Korugan, Aybek; Gupta, Surendra M.

2002-02-01

In this paper, we consider a hybrid manufacturing system with two discrete production lines. Here the output of either production line can satisfy the demand for the same type of product without any penalties. The interarrival times for demand occurrences and service completions are exponentially distributed i.i.d. variables. In order to control this type of manufacturing system we suggest a single stage pull type control mechanism with adaptive kanbans and state independent routing of the production information.

Two-Stage Series-Resonant Inverter

Science.gov (United States)

Stuart, Thomas A.

1994-01-01

Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

85,000-GPM, single-stage, single-suction LMFBR intermediate centrifugal pump

International Nuclear Information System (INIS)

Fair, C.E.; Cook, M.E.; Huber, K.A.; Rohde, R.

1983-01-01

The mechanical and hydraulic design features of the 85,000-gpm, single-stage, single-suction pump test article, which is designed to circulate liquid-sodium coolant in the intermediate heat-transport system of a Large-Scale Liquid Metal Fast Breeder Reactor (LS-LMFBR), are described. The design and analytical considerations used to satisfy the pump performance and operability requirements are presented. The validation of pump hydraulic performance using a hydraulic scale-model pump is discussed, as is the featute test for the mechanical-shaft seal system

Temperature-phased anaerobic digestion of food waste: A comparison with single-stage digestions based on performance and energy balance.

Science.gov (United States)

Xiao, Benyi; Qin, Yu; Zhang, Wenzhe; Wu, Jing; Qiang, Hong; Liu, Junxin; Li, Yu-You

2018-02-01

The temperature-phased anaerobic digestion (TPAD) of food waste was studied for the purpose of comparing with single-stage mesophilic and thermophilic anaerobic digestion. The biogas and methane yields in the TPAD during the steady period were 0.759 ± 0.115 L/g added VS and 0.454 ± 0.201 L/g added VS, which were lower than those in the two single-stage anaerobic digestion. The improper sludge retention time may be the reason for the lower biogas and methane production in TPAD. The removal of volatile solids in the TPAD was 78.55 ± 4.59% and the lowest among the three anaerobic digestion processes. The reaction ratios of the four anaerobic digestion steps in the TPAD were all lower than those in the two single-stage anaerobic digestion. The energy conversion efficiency of the degraded substrate in the TPAD was similar with those in single-stage mesophilic and thermophilic anaerobic digestion systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measuring single-cell density.

Science.gov (United States)

Grover, William H; Bryan, Andrea K; Diez-Silva, Monica; Suresh, Subra; Higgins, John M; Manalis, Scott R

2011-07-05

We have used a microfluidic mass sensor to measure the density of single living cells. By weighing each cell in two fluids of different densities, our technique measures the single-cell mass, volume, and density of approximately 500 cells per hour with a density precision of 0.001 g mL(-1). We observe that the intrinsic cell-to-cell variation in density is nearly 100-fold smaller than the mass or volume variation. As a result, we can measure changes in cell density indicative of cellular processes that would be otherwise undetectable by mass or volume measurements. Here, we demonstrate this with four examples: identifying Plasmodium falciparum malaria-infected erythrocytes in a culture, distinguishing transfused blood cells from a patient's own blood, identifying irreversibly sickled cells in a sickle cell patient, and identifying leukemia cells in the early stages of responding to a drug treatment. These demonstrations suggest that the ability to measure single-cell density will provide valuable insights into cell state for a wide range of biological processes.

Two-stage anaerobic digestion of cheese whey

Energy Technology Data Exchange (ETDEWEB)

Lo, K V; Liao, P H

1986-01-01

A two-stage digestion of cheese whey was studied using two anaerobic rotating biological contact reactors. The second-stage reactor receiving partially treated effluent from the first-stage reactor could be operated at a hydraulic retention time of one day. The results indicated that two-stage digestion is a feasible alternative for treating whey. 6 references.

Methodology of theory of stage-by-stage long-term preparation of sportsmen in single combats

Directory of Open Access Journals (Sweden)

Arziutov G.

2010-04-01

Full Text Available Results over of researches are brought on methodology of theory of stage-by-stage preparation of sportsmen in single combats. The structuralness of theory lies in possibility simple verifications of its substantive provisions, principles and laws. Development of methodology enables to begin creation of map of trainer on the stages of long-term preparation. Laws, conformities to law, principles and rules, must be collected in a map. A map enables the trainers of reserve sport to use its content during all stages of preparation of sportsman.

On the robustness of two-stage estimators

KAUST Repository

Zhelonkin, Mikhail

2012-04-01

The aim of this note is to provide a general framework for the analysis of the robustness properties of a broad class of two-stage models. We derive the influence function, the change-of-variance function, and the asymptotic variance of a general two-stage M-estimator, and provide their interpretations. We illustrate our results in the case of the two-stage maximum likelihood estimator and the two-stage least squares estimator. © 2011.

Sensitivity Analysis in Two-Stage DEA

Directory of Open Access Journals (Sweden)

Athena Forghani

2015-07-01

Full Text Available Data envelopment analysis (DEA is a method for measuring the efficiency of peer decision making units (DMUs which uses a set of inputs to produce a set of outputs. In some cases, DMUs have a two-stage structure, in which the first stage utilizes inputs to produce outputs used as the inputs of the second stage to produce final outputs. One important issue in two-stage DEA is the sensitivity of the results of an analysis to perturbations in the data. The current paper looks into combined model for two-stage DEA and applies the sensitivity analysis to DMUs on the entire frontier. In fact, necessary and sufficient conditions for preserving a DMU's efficiency classiffication are developed when various data changes are applied to all DMUs.

Sensitivity Analysis in Two-Stage DEA

Directory of Open Access Journals (Sweden)

Athena Forghani

2015-12-01

Full Text Available Data envelopment analysis (DEA is a method for measuring the efficiency of peer decision making units (DMUs which uses a set of inputs to produce a set of outputs. In some cases, DMUs have a two-stage structure, in which the first stage utilizes inputs to produce outputs used as the inputs of the second stage to produce final outputs. One important issue in two-stage DEA is the sensitivity of the results of an analysis to perturbations in the data. The current paper looks into combined model for two-stage DEA and applies the sensitivity analysis to DMUs on the entire frontier. In fact, necessary and sufficient conditions for preserving a DMU's efficiency classiffication are developed when various data changes are applied to all DMUs.

Two stage-type railgun accelerator

International Nuclear Information System (INIS)

Ogino, Mutsuo; Azuma, Kingo.

1995-01-01

The present invention provides a two stage-type railgun accelerator capable of spiking a flying body (ice pellet) formed by solidifying a gaseous hydrogen isotope as a fuel to a thermonuclear reactor at a higher speed into a central portion of plasmas. Namely, the two stage-type railgun accelerator accelerates the flying body spiked from a initial stage accelerator to a portion between rails by Lorentz force generated when electric current is supplied to the two rails by way of a plasma armature. In this case, two sets of solenoids are disposed for compressing the plasma armature in the longitudinal direction of the rails. The first and the second sets of solenoid coils are previously supplied with electric current. After passing of the flying body, the armature formed into plasmas by a gas laser disposed at the back of the flying body is compressed in the longitudinal direction of the rails by a magnetic force of the first and the second sets of solenoid coils to increase the plasma density. A current density is also increased simultaneously. Then, the first solenoid coil current is turned OFF to accelerate the flying body in two stages by the compressed plasma armature. (I.S.)

Single-session versus staged procedures for elective multivessel percutaneous coronary intervention.

Science.gov (United States)

Toyota, Toshiaki; Morimoto, Takeshi; Shiomi, Hiroki; Yamaji, Kyohei; Ando, Kenji; Ono, Koh; Shizuta, Satoshi; Saito, Naritatsu; Kato, Takao; Kaji, Shuichiro; Furukawa, Yutaka; Nakagawa, Yoshihisa; Kadota, Kazushige; Horie, Minoru; Kimura, Takeshi

2018-06-01

To clarify the effect of single-session multivessel percutaneous coronary intervention (PCI) strategy relative to the staged multivessel strategy on clinical outcomes in patients with stable coronary artery disease (CAD) or non-ST-elevation acute coronary syndrome. In the Coronary REvascularisation Demonstrating Outcome Study in Kyoto PCI/coronary artery bypass grafting registry cohort-2, there were 2018 patients who underwent elective multivessel PCI. Primary outcome measure was composite of all-cause death, myocardial infarction and stroke at 5-year follow-up. Single-session multivessel PCI and staged multivessel PCI were performed in 707 patients (35.0%) and 1311 patients (65.0%), respectively. The cumulative 5-year incidence of and adjusted risk for the primary outcome measure were not significantly different between the single-session and staged groups (26.7% vs 23.0%, p=0.45; HR 0.91, 95% CI 0.72 to 1.16, p=0.47). The 30-day incidence of all-cause death was significantly higher in the single-session group than in the staged group (1.1% vs 0.2%, p=0.009). However, the causes of death in 11 patients who died within 30 days were generally not related to the procedural complications, but related to the serious clinical status before PCI. For the subgroup analyses including age, gender, extent of CAD, severe chronic kidney disease and heart failure, there was no significant interaction between the subgroup factors and the effect of the single-session strategy relative to the staged strategy for the primary outcome measure. The single-session multivessel PCI strategy was associated with at least comparable 5-year clinical outcomes compared with the staged multivessel PCI, although the prevalence of the single-session strategy was low in the present study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Modeling condom-use stage of change in low-income, single, urban women.

Science.gov (United States)

Morrison-Beedy, Dianne; Carey, Michael P; Lewis, Brian P

2002-04-01

This study was undertaken to identify and test a model of the cognitive antecedents to condom use stage of change in low-income, single, urban women. A convenience sample of 537 women (M=30 years old) attending two urban primary health care settings in western New York State anonymously completed questionnaires based primarily on two leading social-cognitive models, the transtheoretical model and the information-motivation-behavioral skills model. We used structural equation modeling to examine the direct and indirect effects of HIV-related knowledge, social norms of discussing HIV risk and prevention, familiarity with HIV-infected persons, general readiness to change sexual behaviors, perceived vulnerability to HIV, and pros and cons of condom use on condom-use stage of change. The results indicated two models that differ by partner type. Condom-use stage of change in women with steady main partners was influenced most by social norms and the pros of condom use. Condom-use stage of change in women with "other" types (multiple, casual, or new) of sexual partners was influenced by HIV-related knowledge, general readiness to change sexual behaviors, and the pros of condom use. These findings suggest implications for developing gender-relevant HIV-prevention interventions. Copyright 2002 Wiley Periodicals, Inc.

Intracranial MRA: single volume vs. multiple thin slab 3D time-of-flight acquisition.

Science.gov (United States)

Davis, W L; Warnock, S H; Harnsberger, H R; Parker, D L; Chen, C X

1993-01-01

Single volume three-dimensional (3D) time-of-flight (TOF) MR angiography is the most commonly used noninvasive method for evaluating the intracranial vasculature. The sensitivity of this technique to signal loss from flow saturation limits its utility. A recently developed multislab 3D TOF technique, MOTSA, is less affected by flow saturation and would therefore be expected to yield improved vessel visualization. To study this hypothesis, intracranial MR angiograms were obtained on 10 volunteers using three techniques: MOTSA, single volume 3D TOF using a standard 4.9 ms TE (3D TOFA), and single volume 3D TOF using a 6.8 ms TE (3D TOFB). All three sets of axial source images and maximum intensity projection (MIP) images were reviewed. Each exam was evaluated for the number of intracranial vessels visualized. A total of 502 vessel segments were studied with each technique. With use of the MIP images, 86% of selected vessels were visualized with MOTSA, 64% with 3D TOFA (TE = 4.9 ms), and 67% with TOFB (TE = 6.8 ms). Similarly, with the axial source images, 91% of selected vessels were visualized with MOTSA, 77% with 3D TOFA (TE = 4.9 ms), and 82% with 3D TOFB (TE = 6.8 ms). There is improved visualization of selected intracranial vessels in normal volunteers with MOTSA as compared with single volume 3D TOF. These improvements are believed to be primarily a result of decreased sensitivity to flow saturation seen with the MOTSA technique. No difference in overall vessel visualization was noted for the two single volume 3D TOF techniques.

Two-step two-stage fission gas release model

International Nuclear Information System (INIS)

Kim, Yong-soo; Lee, Chan-bock

2006-01-01

Based on the recent theoretical model, two-step two-stage model is developed which incorporates two stage diffusion processes, grain lattice and grain boundary diffusion, coupled with the two step burn-up factor in the low and high burn-up regime. FRAPCON-3 code and its in-pile data sets have been used for the benchmarking and validation of this model. Results reveals that its prediction is in better agreement with the experimental measurements than that by any model contained in the FRAPCON-3 code such as ANS 5.4, modified ANS5.4, and Forsberg-Massih model over whole burn-up range up to 70,000 MWd/MTU. (author)

Plasma gasification of refuse derived fuel in a single-stage system using different gasifying agents.

Science.gov (United States)

Agon, N; Hrabovský, M; Chumak, O; Hlína, M; Kopecký, V; Masláni, A; Bosmans, A; Helsen, L; Skoblja, S; Van Oost, G; Vierendeels, J

2016-01-01

The renewable evolution in the energy industry and the depletion of natural resources are putting pressure on the waste industry to shift towards flexible treatment technologies with efficient materials and/or energy recovery. In this context, a thermochemical conversion method of recent interest is plasma gasification, which is capable of producing syngas from a wide variety of waste streams. The produced syngas can be valorized for both energetic (heat and/or electricity) and chemical (ammonia, hydrogen or liquid hydrocarbons) end-purposes. This paper evaluates the performance of experiments on a single-stage plasma gasification system for the treatment of refuse-derived fuel (RDF) from excavated waste. A comparative analysis of the syngas characteristics and process yields was done for seven cases with different types of gasifying agents (CO2+O2, H2O, CO2+H2O and O2+H2O). The syngas compositions were compared to the thermodynamic equilibrium compositions and the performance of the single-stage plasma gasification of RDF was compared to that of similar experiments with biomass and to the performance of a two-stage plasma gasification process with RDF. The temperature range of the experiment was from 1400 to 1600 K and for all cases, a medium calorific value syngas was produced with lower heating values up to 10.9 MJ/Nm(3), low levels of tar, high levels of CO and H2 and which composition was in good agreement to the equilibrium composition. The carbon conversion efficiency ranged from 80% to 100% and maximum cold gas efficiency and mechanical gasification efficiency of respectively 56% and 95%, were registered. Overall, the treatment of RDF proved to be less performant than that of biomass in the same system. Compared to a two-stage plasma gasification system, the produced syngas from the single-stage reactor showed more favourable characteristics, while the recovery of the solid residue as a vitrified slag is an advantage of the two-stage set-up. Copyright �

Two-stage revision of septic knee prosthesis with articulating knee spacers yields better infection eradication rate than one-stage or two-stage revision with static spacers.

Science.gov (United States)

Romanò, C L; Gala, L; Logoluso, N; Romanò, D; Drago, L

2012-12-01

The best method for treating chronic periprosthetic knee infection remains controversial. Randomized, comparative studies on treatment modalities are lacking. This systematic review of the literature compares the infection eradication rate after two-stage versus one-stage revision and static versus articulating spacers in two-stage procedures. We reviewed full-text papers and those with an abstract in English published from 1966 through 2011 that reported the success rate of infection eradication after one-stage or two-stage revision with two different types of spacers. In all, 6 original articles reporting the results after one-stage knee exchange arthoplasty (n = 204) and 38 papers reporting on two-stage revision (n = 1,421) were reviewed. The average success rate in the eradication of infection was 89.8% after a two-stage revision and 81.9% after a one-stage procedure at a mean follow-up of 44.7 and 40.7 months, respectively. The average infection eradication rate after a two-stage procedure was slightly, although significantly, higher when an articulating spacer rather than a static spacer was used (91.2 versus 87%). The methodological limitations of this study and the heterogeneous material in the studies reviewed notwithstanding, this systematic review shows that, on average, a two-stage procedure is associated with a higher rate of eradication of infection than one-stage revision for septic knee prosthesis and that articulating spacers are associated with a lower recurrence of infection than static spacers at a comparable mean duration of follow-up. IV.

The Incidence of Complications in Single-stage Endoscopic Stone Removal for Patients with Common Bile Duct Stones: A Propensity Score Analysis.

Science.gov (United States)

Saito, Hirokazu; Kadono, Yoshihiro; Kamikawa, Kentaro; Urata, Atsushi; Imamura, Haruo; Matsushita, Ikuo; Kakuma, Tatsuyuki; Tada, Shuji

2018-02-15

Objective Single-stage endoscopic stone removal for choledocholithiasis is an advantageous approach because it is associated with a shorter hospital stay; however, few studies have reported the incidence of complications related to this procedure in detail. The aim of this study was to examine the incidence of complications and efficacy of this procedure. Methods This retrospective study investigated the incidence of complications in 345 patients with naive papilla who underwent therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis at three institutions between April 2014 and March 2016 by a propensity score analysis. The efficacy of single-stage endoscopic stone removal was assessed based on a hospital stay of within 7 days and the number of ERCP attempts. Results Among 114 patients who underwent single-stage endoscopic stone removal, 15 patients (13.2%) experienced complications. Among the remaining 231 patients in the two-stage endoscopic stone removal group, complications were observed in 17 patients (7.4%). The propensity score analysis, which was adjusted for confounding factors, revealed that single-stage endoscopic stone removal was not a significant risk factor for complications (p=0.52). In patients in whom >10 min was required for deep cannulation, single-stage endoscopic stone removal was not a significant risk factor for complications in the propensity score analysis (p=0.37). In the single-stage group, the proportion of patients with a hospital stay of within 7 days was significantly higher and the number of ERCP attempts was significantly lower in comparison to the two-stage group (p <0.0001 and <0.0001, respectively). Conclusion Single-stage endoscopic stone removal did not increase the incidence of complications associated with ERCP and was effective for reducing the hospital stay and the number of ERCP attempts.

Two stages of economic development

OpenAIRE

Gong, Gang

2016-01-01

This study suggests that the development process of a less-developed country can be divided into two stages, which demonstrate significantly different properties in areas such as structural endowments, production modes, income distribution, and the forces that drive economic growth. The two stages of economic development have been indicated in the growth theory of macroeconomics and in the various "turning point" theories in development economics, including Lewis's dual economy theory, Kuznet...

Two-step single slope/SAR ADC with error correction for CMOS image sensor.

Science.gov (United States)

Tang, Fang; Bermak, Amine; Amira, Abbes; Amor Benammar, Mohieddine; He, Debiao; Zhao, Xiaojin

2014-01-01

Conventional two-step ADC for CMOS image sensor requires full resolution noise performance in the first stage single slope ADC, leading to high power consumption and large chip area. This paper presents an 11-bit two-step single slope/successive approximation register (SAR) ADC scheme for CMOS image sensor applications. The first stage single slope ADC generates a 3-bit data and 1 redundant bit. The redundant bit is combined with the following 8-bit SAR ADC output code using a proposed error correction algorithm. Instead of requiring full resolution noise performance, the first stage single slope circuit of the proposed ADC can tolerate up to 3.125% quantization noise. With the proposed error correction mechanism, the power consumption and chip area of the single slope ADC are significantly reduced. The prototype ADC is fabricated using 0.18 μ m CMOS technology. The chip area of the proposed ADC is 7 μ m × 500 μ m. The measurement results show that the energy efficiency figure-of-merit (FOM) of the proposed ADC core is only 125 pJ/sample under 1.4 V power supply and the chip area efficiency is 84 k  μ m(2) · cycles/sample.

Two-Step Single Slope/SAR ADC with Error Correction for CMOS Image Sensor

Directory of Open Access Journals (Sweden)

Fang Tang

2014-01-01

Full Text Available Conventional two-step ADC for CMOS image sensor requires full resolution noise performance in the first stage single slope ADC, leading to high power consumption and large chip area. This paper presents an 11-bit two-step single slope/successive approximation register (SAR ADC scheme for CMOS image sensor applications. The first stage single slope ADC generates a 3-bit data and 1 redundant bit. The redundant bit is combined with the following 8-bit SAR ADC output code using a proposed error correction algorithm. Instead of requiring full resolution noise performance, the first stage single slope circuit of the proposed ADC can tolerate up to 3.125% quantization noise. With the proposed error correction mechanism, the power consumption and chip area of the single slope ADC are significantly reduced. The prototype ADC is fabricated using 0.18 μm CMOS technology. The chip area of the proposed ADC is 7 μm × 500 μm. The measurement results show that the energy efficiency figure-of-merit (FOM of the proposed ADC core is only 125 pJ/sample under 1.4 V power supply and the chip area efficiency is 84 k μm2·cycles/sample.

Metastatic volume: an old oncologic concept and a new prognostic factor for stage IV melanoma patients.

Science.gov (United States)

Panasiti, V; Curzio, M; Roberti, V; Lieto, P; Devirgiliis, V; Gobbi, S; Naspi, A; Coppola, R; Lopez, T; di Meo, N; Gatti, A; Trevisan, G; Londei, P; Calvieri, S

2013-01-01

The last melanoma staging system of the 2009 American Joint Committee on Cancer takes into account, for stage IV disease, the serum levels of lactate dehydrogenase (LDH) and the site of distant metastases. Our aim was to compare the significance of metastatic volume, as evaluated at the time of stage IV melanoma diagnosis, with other clinical predictors of prognosis. We conducted a retrospective multicentric study. To establish which variables were statistically correlated both with death and survival time, contingency tables were evaluated. The overall survival curves were compared using the Kaplan-Meier method. Metastatic volume and number of affected organs were statistically related to death. In detail, patients with a metastatic volume >15 cm(3) had a worse prognosis than those with a volume lower than this value (survival probability at 60 months: 6.8 vs. 40.9%, respectively). The Kaplan-Meier method confirmed that survival time was significantly related to the site(s) of metastases, to elevated LDH serum levels and to melanoma stage according to the latest system. Our results suggest that metastatic volume may be considered as a useful prognostic factor for survival among melanoma patients.

Single-dose volume regulation algorithm for a gas-compensated intrathecal infusion pump.

Science.gov (United States)

Nam, Kyoung Won; Kim, Kwang Gi; Sung, Mun Hyun; Choi, Seong Wook; Kim, Dae Hyun; Jo, Yung Ho

2011-01-01

The internal pressures of medication reservoirs of gas-compensated intrathecal medication infusion pumps decrease when medication is discharged, and these discharge-induced pressure drops can decrease the volume of medication discharged. To prevent these reductions, the volumes discharged must be adjusted to maintain the required dosage levels. In this study, the authors developed an automatic control algorithm for an intrathecal infusion pump developed by the Korean National Cancer Center that regulates single-dose volumes. The proposed algorithm estimates the amount of medication remaining and adjusts control parameters automatically to maintain single-dose volumes at predetermined levels. Experimental results demonstrated that the proposed algorithm can regulate mean single-dose volumes with a variation of 98%. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Investigation of Advanced Propellants to Enable Single Stage to Orbit Launch Vehicles

National Research Council Canada - National Science Library

Mossman, Jason

2006-01-01

Single-Stage-To-Orbit (SSTO) launch vehicles designs offer the promise of reduced complexity and cost compared to multi-stage vehicles, as only one stage need be developed, produced, and maintained...

An integrated single- and two-photon non-diffracting light-sheet microscope

Science.gov (United States)

Lau, Sze Cheung; Chiu, Hoi Chun; Zhao, Luwei; Zhao, Teng; Loy, M. M. T.; Du, Shengwang

2018-04-01

We describe a fluorescence optical microscope with both single-photon and two-photon non-diffracting light-sheet excitations for large volume imaging. With a special design to accommodate two different wavelength ranges (visible: 400-700 nm and near infrared: 800-1200 nm), we combine the line-Bessel sheet (LBS, for single-photon excitation) and the scanning Bessel beam (SBB, for two-photon excitation) light sheet together in a single microscope setup. For a transparent thin sample where the scattering can be ignored, the LBS single-photon excitation is the optimal imaging solution. When the light scattering becomes significant for a deep-cell or deep-tissue imaging, we use SBB light-sheet two-photon excitation with a longer wavelength. We achieved nearly identical lateral/axial resolution of about 350/270 nm for both imagings. This integrated light-sheet microscope may have a wide application for live-cell and live-tissue three-dimensional high-speed imaging.

Building fast well-balanced two-stage numerical schemes for a model of two-phase flows

Science.gov (United States)

Thanh, Mai Duc

2014-06-01

We present a set of well-balanced two-stage schemes for an isentropic model of two-phase flows arisen from the modeling of deflagration-to-detonation transition in granular materials. The first stage is to absorb the source term in nonconservative form into equilibria. Then in the second stage, these equilibria will be composed into a numerical flux formed by using a convex combination of the numerical flux of a stable Lax-Friedrichs-type scheme and the one of a higher-order Richtmyer-type scheme. Numerical schemes constructed in such a way are expected to get the interesting property: they are fast and stable. Tests show that the method works out until the parameter takes on the value CFL, and so any value of the parameter between zero and this value is expected to work as well. All the schemes in this family are shown to capture stationary waves and preserves the positivity of the volume fractions. The special values of the parameter 0,1/2,1/(1+CFL), and CFL in this family define the Lax-Friedrichs-type, FAST1, FAST2, and FAST3 schemes, respectively. These schemes are shown to give a desirable accuracy. The errors and the CPU time of these schemes and the Roe-type scheme are calculated and compared. The constructed schemes are shown to be well-balanced and faster than the Roe-type scheme.

Design and control of a decoupled two degree of freedom translational parallel micro-positioning stage.

Science.gov (United States)

Lai, Lei-Jie; Gu, Guo-Ying; Zhu, Li-Min

2012-04-01

This paper presents a novel decoupled two degrees of freedom (2-DOF) translational parallel micro-positioning stage. The stage consists of a monolithic compliant mechanism driven by two piezoelectric actuators. The end-effector of the stage is connected to the base by four independent kinematic limbs. Two types of compound flexure module are serially connected to provide 2-DOF for each limb. The compound flexure modules and mirror symmetric distribution of the four limbs significantly reduce the input and output cross couplings and the parasitic motions. Based on the stiffness matrix method, static and dynamic models are constructed and optimal design is performed under certain constraints. The finite element analysis results are then given to validate the design model and a prototype of the XY stage is fabricated for performance tests. Open-loop tests show that maximum static and dynamic cross couplings between the two linear motions are below 0.5% and -45 dB, which are low enough to utilize the single-input-single-out control strategies. Finally, according to the identified dynamic model, an inversion-based feedforward controller in conjunction with a proportional-integral-derivative controller is applied to compensate for the nonlinearities and uncertainties. The experimental results show that good positioning and tracking performances are achieved, which verifies the effectiveness of the proposed mechanism and controller design. The resonant frequencies of the loaded stage at 2 kg and 5 kg are 105 Hz and 68 Hz, respectively. Therefore, the performance of the stage is reasonably good in term of a 200 N load capacity. © 2012 American Institute of Physics

Accuracy of the One-Stage and Two-Stage Impression Techniques: A Comparative Analysis.

Science.gov (United States)

Jamshidy, Ladan; Mozaffari, Hamid Reza; Faraji, Payam; Sharifi, Roohollah

2016-01-01

Introduction . One of the main steps of impression is the selection and preparation of an appropriate tray. Hence, the present study aimed to analyze and compare the accuracy of one- and two-stage impression techniques. Materials and Methods . A resin laboratory-made model, as the first molar, was prepared by standard method for full crowns with processed preparation finish line of 1 mm depth and convergence angle of 3-4°. Impression was made 20 times with one-stage technique and 20 times with two-stage technique using an appropriate tray. To measure the marginal gap, the distance between the restoration margin and preparation finish line of plaster dies was vertically determined in mid mesial, distal, buccal, and lingual (MDBL) regions by a stereomicroscope using a standard method. Results . The results of independent test showed that the mean value of the marginal gap obtained by one-stage impression technique was higher than that of two-stage impression technique. Further, there was no significant difference between one- and two-stage impression techniques in mid buccal region, but a significant difference was reported between the two impression techniques in MDL regions and in general. Conclusion . The findings of the present study indicated higher accuracy for two-stage impression technique than for the one-stage impression technique.

Attainability and minimum energy of single-stage membrane and membrane/distillation hybrid processes

KAUST Repository

Alshehri, Ali

2014-12-01

As an energy-efficient separation method, membrane technology has attracted more and more attentions in many challenging separation processes. The attainability and the energy consumption of a membrane process are the two basic fundamental questions that need to be answered. This report aims to use process simulations to find: (1) at what conditions a single-stage membrane process can meet the separation task that is defined by product purity and recovery ratio and (2) what are the most important parameters that determine the energy consumption. To perform a certain separation task, it was found that both membrane selectivity and pressure ratio exhibit a minimum value that is defined only by product purity and recovery ratio. The membrane/distillation hybrid system was used to study the energy consumption. A shortcut method was developed to calculate the minimum practical separation energy (MPSE) of the membrane process and the distillation process. It was found that the MPSE of the hybrid system is only determined by the membrane selectivity and the applied transmembrane pressure ratio in three stages. At the first stage when selectivity is low, the membrane process is not competitive to the distillation process. Adding a membrane unit to a distillation tower will not help in reducing energy. At the second medium selectivity stage, the membrane/distillation hybrid system can help reduce the energy consumption, and the higher the membrane selectivity, the lower is the energy. The energy conservation is further improved as pressure ratio increases. At the third stage when both selectivity and pressure ratio are high, the hybrid system will change to a single-stage membrane unit and this change will cause significant reduction in energy consumption. The energy at this stage keeps decreasing with selectivity at slow rate, but slightly increases with pressure ratio. Overall, the higher the membrane selectivity, the more the energy is saved. Therefore, the two

Spectral Characteristic Based on Fabry—Pérot Laser Diode with Two-Stage Optical Feedback

International Nuclear Information System (INIS)

Wu Jian-Wei; Nakarmi Bikash

2013-01-01

An optical device, consisting of a multi-mode Fabry—Pérot laser diode (MMFP-LD) with two-stage optical feedback, is proposed and experimentally demonstrated. The results show that the single-mode output with side-mode suppression ratio (SMSR) of ∼21.7 dB is attained by using the first-stage feedback. By using the second-stage feedback, the SMSR of single-mode operation could be increased to ∼28.5 dB while injection feedback power of −29 dBm is introduced into the laser diode. In the case of up to −29 dBm feedback power, the outcome SMSR is rapidly decayed to a very low level so that an obvious multi-mode operation in the output spectrum could be achieved at the feedback power level of −15.5 dBm. Thus, a transition between single- and multi-mode operations could be flexibly controlled by adjusting the injected power in the second-stage feedback system. Additionally, in the case of injection locking, the outcome SMSR and output power at the locked wavelength are as high as ∼50 dB and ∼5.8 dBm, respectively

Studies of left ventricular volume estimation from single photon emission computed tomography

International Nuclear Information System (INIS)

Hiraki, Yoshio; Shimizu, Mitsuharu; Joja, Ikuo; Aono, Kaname; Yanagi, Hidekiyo; Indo, Haruaki; Seno, Yoshimasa; Teramoto, Shigeru; Nagaya, Isao.

1988-01-01

We studied the comparative accuracy of 99m Tc cardiac blood pool Single Photon Emission Computed Tomography (SPECT) for the measurement of left ventricular volume in 20 patients undergoing SPECT and single plane contrast left ventriculography (LVG). Left ventricular volume was calculated based on the total number of voxels in left ventricle. End-diastolic left ventricular volume (EDV) and end-systolic left ventricular volume (ESV) calculated from SPECT were compared with those from LVG. SPECT volume values showed a high degree of correlation with those by LVG (r = 0.923 for EDV, r = 0.903 for ESV). We appreciated the usefulness and accuracy of SPECT in measuring left ventricular volume because of its three-dimensional information. (author)

Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

KAUST Repository

Alfazazi, Adamu; Kuti, Olawole Abiola; Naser, Nimal; Chung, Suk-Ho; Sarathy, Mani

2016-01-01

The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate

Accuracy of the One-Stage and Two-Stage Impression Techniques: A Comparative Analysis

Directory of Open Access Journals (Sweden)

Ladan Jamshidy

2016-01-01

Full Text Available Introduction. One of the main steps of impression is the selection and preparation of an appropriate tray. Hence, the present study aimed to analyze and compare the accuracy of one- and two-stage impression techniques. Materials and Methods. A resin laboratory-made model, as the first molar, was prepared by standard method for full crowns with processed preparation finish line of 1 mm depth and convergence angle of 3-4°. Impression was made 20 times with one-stage technique and 20 times with two-stage technique using an appropriate tray. To measure the marginal gap, the distance between the restoration margin and preparation finish line of plaster dies was vertically determined in mid mesial, distal, buccal, and lingual (MDBL regions by a stereomicroscope using a standard method. Results. The results of independent test showed that the mean value of the marginal gap obtained by one-stage impression technique was higher than that of two-stage impression technique. Further, there was no significant difference between one- and two-stage impression techniques in mid buccal region, but a significant difference was reported between the two impression techniques in MDL regions and in general. Conclusion. The findings of the present study indicated higher accuracy for two-stage impression technique than for the one-stage impression technique.

Promising results after single-stage reconstruction of the nipple and areola complex

DEFF Research Database (Denmark)

Børsen-Koch, Mikkel; Bille, Camilla; Thomsen, Jørn B

2013-01-01

Introduction: Reconstruction of the nipple-areola complex (NAC) traditionally marks the end of breast reconstruction. Several different surgical techniques have been described, but most are staged procedures. This paper describes a simple single-stage approach. Material and Methods: We used...... reconstruction was 43 min. (30-50 min.). Conclusion: This simple single-stage NAC reconstruction seems beneficial for both patient and surgeon as it seems to be associated with faster reconstruction and reduced procedure-related time without compromising the aesthetic outcome or the morbidity associated...

DeepSleepNet: A Model for Automatic Sleep Stage Scoring Based on Raw Single-Channel EEG.

Science.gov (United States)

Supratak, Akara; Dong, Hao; Wu, Chao; Guo, Yike

2017-11-01

This paper proposes a deep learning model, named DeepSleepNet, for automatic sleep stage scoring based on raw single-channel EEG. Most of the existing methods rely on hand-engineered features, which require prior knowledge of sleep analysis. Only a few of them encode the temporal information, such as transition rules, which is important for identifying the next sleep stages, into the extracted features. In the proposed model, we utilize convolutional neural networks to extract time-invariant features, and bidirectional-long short-term memory to learn transition rules among sleep stages automatically from EEG epochs. We implement a two-step training algorithm to train our model efficiently. We evaluated our model using different single-channel EEGs (F4-EOG (left), Fpz-Cz, and Pz-Oz) from two public sleep data sets, that have different properties (e.g., sampling rate) and scoring standards (AASM and R&K). The results showed that our model achieved similar overall accuracy and macro F1-score (MASS: 86.2%-81.7, Sleep-EDF: 82.0%-76.9) compared with the state-of-the-art methods (MASS: 85.9%-80.5, Sleep-EDF: 78.9%-73.7) on both data sets. This demonstrated that, without changing the model architecture and the training algorithm, our model could automatically learn features for sleep stage scoring from different raw single-channel EEGs from different data sets without utilizing any hand-engineered features.

Evaluation of single and two-stage adaptive sampling designs for estimation of density and abundance of freshwater mussels in a large river

Science.gov (United States)

Smith, D.R.; Rogala, J.T.; Gray, B.R.; Zigler, S.J.; Newton, T.J.

2011-01-01

Reliable estimates of abundance are needed to assess consequences of proposed habitat restoration and enhancement projects on freshwater mussels in the Upper Mississippi River (UMR). Although there is general guidance on sampling techniques for population assessment of freshwater mussels, the actual performance of sampling designs can depend critically on the population density and spatial distribution at the project site. To evaluate various sampling designs, we simulated sampling of populations, which varied in density and degree of spatial clustering. Because of logistics and costs of large river sampling and spatial clustering of freshwater mussels, we focused on adaptive and non-adaptive versions of single and two-stage sampling. The candidate designs performed similarly in terms of precision (CV) and probability of species detection for fixed sample size. Both CV and species detection were determined largely by density, spatial distribution and sample size. However, designs did differ in the rate that occupied quadrats were encountered. Occupied units had a higher probability of selection using adaptive designs than conventional designs. We used two measures of cost: sample size (i.e. number of quadrats) and distance travelled between the quadrats. Adaptive and two-stage designs tended to reduce distance between sampling units, and thus performed better when distance travelled was considered. Based on the comparisons, we provide general recommendations on the sampling designs for the freshwater mussels in the UMR, and presumably other large rivers.

Single-stage Modified Duhamel procedure for Hirschsprung′s disease : Our experience

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Paras R Kothari

2012-01-01

Full Text Available Introduction: Primary single-stage pull-through for Hirschsprung′s disease (HD has been reported to give comparable surgical outcomes to staged operations with less morbidity. Herein, we present our experience with single-stage Modified Duhamel procedure for management of HD. Patients and Methods: This was a review of 48 cases of HD who underwent single-stage Modified Duhamel procedure without a protective colostomy. Results: The age at surgery ranged from 6 months to 10 years (median - 9 months, mean - 2.3 years. The average weight of the child was 7.2 kg (range, 4.9-22 kg. 38 (79.2% patients had classical rectosigmoid HD, the rest being long segment HD (the proximal most level being the splenic flexure. The average duration of surgery was 175 minutes (range, 130-245 minutes. The average blood loss was 45 ml. The average hospital stay was 7.2 days (range: 6-10 days. The major postoperative complications (n=3 included postoperative adhesive intestinal obstruction, anastomotic leak and persistent constipation due to residual aganglionosis. Each required a re-exploration. Minor complications included surgical site infection (n=3 and post-operative enterocolitis (n=3, which were managed conservatively. Six patients had constipation for a limited period post-operatively. All patients have a satisfactory functional outcome and normal development and growth. Conclusions: For HD, we recommend that single-stage Modified Duhamel procedure should be the preferred approach in view of its low morbidity, satisfactory functional outcome and avoidance of stoma, multiple surgeries and economic benefit in view of decreased hospital stay.

Single-stage three-phase AC to DC conversion with isolation and Bi-directional power flow

NARCIS (Netherlands)

Vermulst, B.J.D.; Duarte, J.L.; Wijnands, C.G.E.; Lomonova, E.A.

2014-01-01

An approach for three-phase AC to DC conversion is proposed, which consists of a single-stage while offering galvanic isolation, soft-switching, bi-directional power flow and a significant reduction of inductive and capacitive energy storage. Two elements enable this approach, namely a neutral

Lot-sizing for a single-stage single-product production system with rework of perishable production defectives

NARCIS (Netherlands)

Teunter, R.; Flapper, S.D.P.

2003-01-01

We consider a single-stage single-product production system. Produced units may be non-defective, reworkable defective, or non-reworkable defective. The system switches between production and rework. After producing a fixed number (N) of units, all reworkable defective units are reworked. Reworkable

A tetrad of bicuspid aortic valve association: A single-stage repair

Science.gov (United States)

Barik, Ramachandra; Patnaik, A. N.; Mishra, Ramesh C.; Kumari, N. Rama; Gulati, A. S.

2012-01-01

We report a 27 years old male who presented with a combination of both congenital and acquired cardiac defects. This syndrome complex includes congenital bicuspid aortic valve, Seller's grade II aortic regurgitation, juxta- subclavian coarctation, stenosis of ostium of left subclavian artery and ruptured sinus of Valsalva aneurysm without any evidence of infective endocarditis. This type of constellation is extremely rare. Neither coarctation of aorta with left subclavian artery stenosis nor the rupture of sinus Valsalva had a favorable pathology for percutaneus intervention. Taking account into morbidity associated with repeated surgery and anesthesia patient underwent a single stage surgical repair of both the defects by two surgical incisions. The approaches include median sternotomy for rupture of sinus of Valsalva and lateral thoracotomy for coarctation with left subclavian artery stenosis. The surgery was uneventful. After three months follow up echocardiography showed mild residual gradient across the repaired coarctation segment, mild aortic regurgitation and no residual left to right shunt. This patient is under follow up. This is an extremely rare case of single stage successful repair of coarctation and rupture of sinus of Valsalva associated with congenital bicuspid aortic valve. PMID:22629035

Bias due to two-stage residual-outcome regression analysis in genetic association studies.

Science.gov (United States)

Demissie, Serkalem; Cupples, L Adrienne

2011-11-01

Association studies of risk factors and complex diseases require careful assessment of potential confounding factors. Two-stage regression analysis, sometimes referred to as residual- or adjusted-outcome analysis, has been increasingly used in association studies of single nucleotide polymorphisms (SNPs) and quantitative traits. In this analysis, first, a residual-outcome is calculated from a regression of the outcome variable on covariates and then the relationship between the adjusted-outcome and the SNP is evaluated by a simple linear regression of the adjusted-outcome on the SNP. In this article, we examine the performance of this two-stage analysis as compared with multiple linear regression (MLR) analysis. Our findings show that when a SNP and a covariate are correlated, the two-stage approach results in biased genotypic effect and loss of power. Bias is always toward the null and increases with the squared-correlation between the SNP and the covariate (). For example, for , 0.1, and 0.5, two-stage analysis results in, respectively, 0, 10, and 50% attenuation in the SNP effect. As expected, MLR was always unbiased. Since individual SNPs often show little or no correlation with covariates, a two-stage analysis is expected to perform as well as MLR in many genetic studies; however, it produces considerably different results from MLR and may lead to incorrect conclusions when independent variables are highly correlated. While a useful alternative to MLR under , the two -stage approach has serious limitations. Its use as a simple substitute for MLR should be avoided. © 2011 Wiley Periodicals, Inc.

Influence of two-stage annealing treatment on critical current of bronze-processed multifilamentary Nb/sub 3/Sn superconducting materials

International Nuclear Information System (INIS)

Ochiai, S.; Osamura, K.; Ryoji, M.

1987-01-01

The influence of changes of volume fraction of Nb/sub 3/Sn, grain size and upper critical magnetic field due to two-stage annealing treatment (low temperature annealing to form fine grains + high temperature annealing to raise upper critical magnetic field) on overall critical current and critical current density were studied at magnetic field of 3-15 T. When annealing temperature was low (773-923 K) and the volume fraction of Nb/sub 3/Sn was low in first stage annealing, second stage annealing could raise the overall critical current over the range of the applied magnetic field due to increase in upper critical magnetic field H/sub c2/ and volume fraction of Nb/sub 3/Sn accompanying with reduction in Sn concentration in the bronze matrix, which played a role to reduce residual strain in Nb/sub 3/Sn, leading to high H/sub c2/ although the loss in pinning force arose from the coarsening of the grains. When the annealing temperature was high (973 K) and the Nb/sub 3/Sn was formed until the Sn was consumed in the first stage, second stage annealing could not raise the critical current due to increase in grain size and no effective increase in H/sub c2/. The critical current density at low magnetic fields below several Teslas was reduced by the second stage annealing due to increase in grain size but that at high fields was raised due to increase in high H/sub c2/. The reverse two-stage annealing treatment (high temperature annealing in the first stage+low temperature annealing in the second stage) reduced the H/sub c2/ slightly with increasing second stage annealing temperature and time. The critical current density at low magnetic fields was determined mainly by the grain size and that at high fields was determined by the combination of the upper critical field and grain size

Comparison of two-stage thermophilic (68 degrees C/55 degrees C) anaerobic digestion with one-stage thermophilic (55 degrees C) digestion of cattle manure.

Science.gov (United States)

Nielsen, H B; Mladenovska, Z; Westermann, P; Ahring, B K

2004-05-05

A two-stage 68 degrees C/55 degrees C anaerobic degradation process for treatment of cattle manure was studied. In batch experiments, an increase of the specific methane yield, ranging from 24% to 56%, was obtained when cattle manure and its fractions (fibers and liquid) were pretreated at 68 degrees C for periods of 36, 108, and 168 h, and subsequently digested at 55 degrees C. In a lab-scale experiment, the performance of a two-stage reactor system, consisting of a digester operating at 68 degrees C with a hydraulic retention time (HRT) of 3 days, connected to a 55 degrees C reactor with 12-day HRT, was compared with a conventional single-stage reactor running at 55 degrees C with 15-days HRT. When an organic loading of 3 g volatile solids (VS) per liter per day was applied, the two-stage setup had a 6% to 8% higher specific methane yield and a 9% more effective VS-removal than the conventional single-stage reactor. The 68 degrees C reactor generated 7% to 9% of the total amount of methane of the two-stage system and maintained a volatile fatty acids (VFA) concentration of 4.0 to 4.4 g acetate per liter. Population size and activity of aceticlastic methanogens, syntrophic bacteria, and hydrolytic/fermentative bacteria were significantly lower in the 68 degrees C reactor than in the 55 degrees C reactors. The density levels of methanogens utilizing H2/CO2 or formate were, however, in the same range for all reactors, although the degradation of these substrates was significantly lower in the 68 degrees C reactor than in the 55 degrees C reactors. Temporal temperature gradient electrophoresis profiles (TTGE) of the 68 degrees C reactor demonstrated a stable bacterial community along with a less divergent community of archaeal species. Copyright 2004 Wiley Periodicals, Inc.

Performance study of a heat pump driven and hollow fiber membrane-based two-stage liquid desiccant air dehumidification system

International Nuclear Information System (INIS)

Zhang, Ning; Yin, Shao-You; Zhang, Li-Zhi

2016-01-01

Graphical abstract: A heat pump driven, hollow fiber membrane-based two-stage liquid desiccant air dehumidification system. - Highlights: • A two-stage hollow fiber membrane based air dehumidification is proposed. • It is heat pump driven liquid desiccant system. • Performance is improved 20% upon single stage system. • The optimal first to second stage dehumidification area ratio is 1.4. - Abstract: A novel compression heat pump driven and hollow fiber membrane-based two-stage liquid desiccant air dehumidification system is presented. The liquid desiccant droplets are prevented from crossing over into the process air by the semi-permeable membranes. The isoenthalpic processes are changed to quasi-isothermal processes by the two-stage dehumidification processes. The system is set up and a model is proposed for simulation. Heat and mass capacities in the system, including the membrane modules, the condenser, the evaporator and the heat exchangers are modeled in detail. The model is also validated experimentally. Compared with a single-stage dehumidification system, the two-stage system has a lower solution concentration exiting from the dehumidifier and a lower condensing temperature. Thus, a better thermodynamic system performance is realized and the COP can be increased by about 20% under the typical hot and humid conditions in Southern China. The allocations of heat and mass transfer areas in the system are also investigated. It is found that the optimal regeneration to dehumidification area ratio is 1.33. The optimal first to second stage dehumidification area ratio is 1.4; and the optimal first to second stage regeneration area ratio is 1.286.

Effects of regularly consuming dietary fibre rich soluble cocoa products on bowel habits in healthy subjects: a free-living, two-stage, randomized, crossover, single-blind intervention

Directory of Open Access Journals (Sweden)

Sarriá Beatriz

2012-04-01

Full Text Available Abstract Background Dietary fibre is both preventive and therapeutic for bowel functional diseases. Soluble cocoa products are good sources of dietary fibre that may be supplemented with this dietary component. This study assessed the effects of regularly consuming two soluble cocoa products (A and B with different non-starch polysaccharides levels (NSP, 15.1 and 22.0% w/w, respectively on bowel habits using subjective intestinal function and symptom questionnaires, a daily diary and a faecal marker in healthy individuals. Methods A free-living, two-stage, randomized, crossover, single-blind intervention was carried out in 44 healthy men and women, between 18-55 y old, who had not taken dietary supplements, laxatives, or antibiotics six months before the start of the study. In the four-week-long intervention stages, separated by a three-week-wash-out stage, two servings of A and B, that provided 2.26 vs. 6.60 g/day of NSP respectively, were taken. In each stage, volunteers' diet was recorded using a 72-h food intake report. Results Regularly consuming cocoa A and B increased fibre intake, although only cocoa B significantly increased fibre intake (p Conclusions Regular consumption of the cocoa products increases dietary fibre intake to recommended levels and product B improves bowel habits. The use of both objective and subjective assessments to evaluate the effects of food on bowel habits is recommended.

Single-stage anterior high sacrectomy for locally recurrent rectal cancer.

Science.gov (United States)

Fawaz, Khaled; Khaled, Fawaz; Smith, Myles J; Moises, Cukier; Smith, Andrew J; Yee, Albert J M

2014-03-01

A review of prospectively collected data on a consecutive series of patients undergoing single-stage anterior high sacrectomy for locally recurrent rectal carcinoma (LRRC). To determine the clinical outcome of patients who underwent anterior high sacrectomy for LRRC. High sacrectomy for oncological resection remains technically challenging. Surgery has the potential to achieve cure in carefully selected patients. Complete (R0) tumor excision in LRRC may require sacrectomy. High sacral resections (S3 and above) typically require a combined anterior/supine and posterior/prone procedure. We investigated our experience performing single-stage anterior high sacrectomy for LRRC. A consecutive series of patients with LRRC without systemic metastases who underwent resection with curative intent requiring high sacrectomy were identified. A review of a prospectively maintained colorectal and spine cancer database data was performed. An oblique dome high sacral osteotomy was performed during a single-stage anterior procedure. Outcome measures included surgical resection margin status, hospital length of stay, postoperative complications, physical functioning status, and overall survival. Nineteen consecutive patients were treated between 2002 and 2011. High sacrectomy was performed at sacral level S1-S2 in 4 patients, S2-S3 in 9 patients, and through S3 in 6 patients. An R0 resection margin was achieved histologically in all 19 cases. There was 1 early (<30 d) postoperative death (1/19, 5%). At median follow-up of 38 months, 13 patients had no evidence of residual disease, 1 was alive with disease, and 4 had died of disease. Morbidities occurred in 15 of the 19 patients (79%). Although high sacrectomy may require a combined anterior and posterior surgical approach, our series demonstrates the feasibility of performing single-stage anterior high sacrectomy in LRRC, with acceptable risks and outcomes compared with the literature. The procedure described by us for LRRC lessens

Kinetics of two-stage fermentation process for the production of hydrogen

Energy Technology Data Exchange (ETDEWEB)

Nath, Kaushik [Department of Chemical Engineering, G.H. Patel College of Engineering and Technology, Vallabh Vidyanagar 388 120, Gujarat (India); Muthukumar, Manoj; Kumar, Anish; Das, Debabrata [Fermentation Technology Laboratory, Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302 (India)

2008-02-15

Two-stage process described in the present work is a combination of dark and photofermentation in a sequential batch mode. In the first stage glucose is fermented to acetate, CO{sub 2} and H{sub 2} in an anaerobic dark fermentation by Enterobacter cloacae DM11. This is followed by a successive second stage where acetate is converted to H{sub 2} and CO{sub 2} in a photobioreactor by photosynthetic bacteria, Rhodobacter sphaeroides O.U. 001. The yield of hydrogen in the first stage was about 3.31molH{sub 2}(molglucose){sup -1} (approximately 82% of theoretical) and that in the second stage was about 1.5-1.72molH{sub 2}(molaceticacid){sup -1} (approximately 37-43% of theoretical). The overall yield of hydrogen in two-stage process considering glucose as preliminary substrate was found to be higher compared to a single stage process. Monod model, with incorporation of substrate inhibition term, has been used to determine the growth kinetic parameters for the first stage. The values of maximum specific growth rate ({mu} {sub max}) and K{sub s} (saturation constant) were 0.398h{sup -1} and 5.509gl{sup -1}, respectively, using glucose as substrate. The experimental substrate and biomass concentration profiles have good resemblance with those obtained by kinetic model predictions. A model based on logistic equation has been developed to describe the growth of R. sphaeroides O.U 001 in the second stage. Modified Gompertz equation was applied to estimate the hydrogen production potential, rate and lag phase time in a batch process for various initial concentration of glucose, based on the cumulative hydrogen production curves. Both the curve fitting and statistical analysis showed that the equation was suitable to describe the progress of cumulative hydrogen production. (author)

Single stage buck-boost DC-AC neutral point clamped inverter

DEFF Research Database (Denmark)

Mo, Wei; Loh, Poh Chiang; Andrew, A.

2012-01-01

This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence......, it has enhanced buck-boost functionality and low output voltage distortions compared to the traditional Z-source inverter; it has continuous input current which reduces the source stress and inverter noise; it also contains two built-in capacitors which can block the DC current in the transformer...... windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation...

A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... performed on a 3-kW two-stage single-phase grid-connected PV system, where the power reserve control is achieved upon demands....

FunSAV: predicting the functional effect of single amino acid variants using a two-stage random forest model.

Directory of Open Access Journals (Sweden)

Mingjun Wang

Full Text Available Single amino acid variants (SAVs are the most abundant form of known genetic variations associated with human disease. Successful prediction of the functional impact of SAVs from sequences can thus lead to an improved understanding of the underlying mechanisms of why a SAV may be associated with certain disease. In this work, we constructed a high-quality structural dataset that contained 679 high-quality protein structures with 2,048 SAVs by collecting the human genetic variant data from multiple resources and dividing them into two categories, i.e., disease-associated and neutral variants. We built a two-stage random forest (RF model, termed as FunSAV, to predict the functional effect of SAVs by combining sequence, structure and residue-contact network features with other additional features that were not explored in previous studies. Importantly, a two-step feature selection procedure was proposed to select the most important and informative features that contribute to the prediction of disease association of SAVs. In cross-validation experiments on the benchmark dataset, FunSAV achieved a good prediction performance with the area under the curve (AUC of 0.882, which is competitive with and in some cases better than other existing tools including SIFT, SNAP, Polyphen2, PANTHER, nsSNPAnalyzer and PhD-SNP. The sourcecodes of FunSAV and the datasets can be downloaded at http://sunflower.kuicr.kyoto-u.ac.jp/sjn/FunSAV.

Experimental Results of the First Two Stages of an Advanced Transonic Core Compressor Under Isolated and Multi-Stage Conditions

Science.gov (United States)

Prahst, Patricia S.; Kulkarni, Sameer; Sohn, Ki H.

2015-01-01

NASA's Environmentally Responsible Aviation (ERA) Program calls for investigation of the technology barriers associated with improved fuel efficiency of large gas turbine engines. Under ERA the task for a High Pressure Ratio Core Technology program calls for a higher overall pressure ratio of 60 to 70. This mean that the HPC would have to almost double in pressure ratio and keep its high level of efficiency. The challenge is how to match the corrected mass flow rate of the front two supersonic high reaction and high corrected tip speed stages with a total pressure ratio of 3.5. NASA and GE teamed to address this challenge by using the initial geometry of an advanced GE compressor design to meet the requirements of the first 2 stages of the very high pressure ratio core compressor. The rig was configured to run as a 2 stage machine, with Strut and IGV, Rotor 1 and Stator 1 run as independent tests which were then followed by adding the second stage. The goal is to fully understand the stage performances under isolated and multi-stage conditions and fully understand any differences and provide a detailed aerodynamic data set for CFD validation. Full use was made of steady and unsteady measurement methods to isolate fluid dynamics loss source mechanisms due to interaction and endwalls. The paper will present the description of the compressor test article, its predicted performance and operability, and the experimental results for both the single stage and two stage configurations. We focus the detailed measurements on 97 and 100 of design speed at 3 vane setting angles.

System and method for single-phase, single-stage grid-interactive inverter

Science.gov (United States)

Liu, Liming; Li, Hui

2015-09-01

The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

Single-stage revision for fungal peri-prosthetic joint infection: a single-centre experience.

Science.gov (United States)

Klatte, T O; Kendoff, D; Kamath, A F; Jonen, V; Rueger, J M; Frommelt, L; Gebauer, M; Gehrke, T

2014-04-01

Fungal peri-prosthetic infections of the knee and hip are rare but likely to result in devastating complications. In this study we evaluated the results of their management using a single-stage exchange technique. Between 2001 and 2011, 14 patients (ten hips, four knees) were treated for a peri-prosthetic fungal infection. One patient was excluded because revision surgery was not possible owing to a large acetabular defect. One patient developed a further infection two months post-operatively and was excluded from the analysis. Two patients died of unrelated causes. After a mean of seven years (3 to 11) a total of ten patients were available for follow-up. One patient, undergoing revision replacement of the hip, had a post-operative dislocation. Another patient, undergoing revision replacement of the knee, developed a wound infection and required revision 29 months post-operatively following a peri-prosthetic femoral fracture. The mean Harris hip score increased to 74 points (63 to 84; p prosthetic infection is feasible, with an acceptable rate of a satisfactory outcome.

Strategies and limits in multi-stage single-point incremental forming

DEFF Research Database (Denmark)

Skjødt, Martin; Silva, M.B.; Martins, P. A. F.

2010-01-01

paths. The results also reveal that the sequence of multi-stage forming has a large effect on the location of strain points in the principal strain space. Strain paths are linear in the first stage and highly non-linear in the subsequent forming stages. The overall results show that the experimentally......Multi-stage single-point incremental forming (SPIF) is a state-of-the-art manufacturing process that allows small-quantity production of complex sheet metal parts with vertical walls. This paper is focused on the application of multi-stage SPIF with the objective of producing cylindrical cups......-limit curves and fracture forming-limit curves (FFLCs), numerical simulation, and experimentation, namely the evaluation of strain paths and fracture strains in actual multi-stage parts. Assessment of numerical simulation with experimentation shows good agreement between computed and measured strain and strain...

Evaluation of an automated single-channel sleep staging algorithm

Directory of Open Access Journals (Sweden)

Wang Y

2015-09-01

Full Text Available Ying Wang,1 Kenneth A Loparo,1,2 Monica R Kelly,3 Richard F Kaplan1 1General Sleep Corporation, Euclid, OH, 2Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, 3Department of Psychology, University of Arizona, Tucson, AZ, USA Background: We previously published the performance evaluation of an automated electroencephalography (EEG-based single-channel sleep–wake detection algorithm called Z-ALG used by the Zmachine® sleep monitoring system. The objective of this paper is to evaluate the performance of a new algorithm called Z-PLUS, which further differentiates sleep as detected by Z-ALG into Light Sleep, Deep Sleep, and Rapid Eye Movement (REM Sleep, against laboratory polysomnography (PSG using a consensus of expert visual scorers. Methods: Single night, in-lab PSG recordings from 99 subjects (52F/47M, 18–60 years, median age 32.7 years, including both normal sleepers and those reporting a variety of sleep complaints consistent with chronic insomnia, sleep apnea, and restless leg syndrome, as well as those taking selective serotonin reuptake inhibitor/serotonin–norepinephrine reuptake inhibitor antidepressant medications, previously evaluated using Z-ALG were re-examined using Z-PLUS. EEG data collected from electrodes placed at the differential-mastoids (A1–A2 were processed by Z-ALG to determine wake and sleep, then those epochs detected as sleep were further processed by Z-PLUS to differentiate into Light Sleep, Deep Sleep, and REM. EEG data were visually scored by multiple certified polysomnographic technologists according to the Rechtschaffen and Kales criterion, and then combined using a majority-voting rule to create a PSG Consensus score file for each of the 99 subjects. Z-PLUS output was compared to the PSG Consensus score files for both epoch-by-epoch (eg, sensitivity, specificity, and kappa and sleep stage-related statistics (eg, Latency to Deep Sleep, Latency to REM

Use of skin stretchers for single-stage bilateral mastectomies in a dog and a cat.

Science.gov (United States)

Miyazaki, Yuta; Aikawa, Takeshi; Shimatsu, Taichi; Nishimura, Masaaki; Sadahiro, Shigeo

2018-04-01

To describe the application of skin stretchers for closure of single-stage bilateral mastectomies in a dog and a cat. Clinical case report. A 12-year-old intact female Miniature Dachshund and a 13-year-old spayed female domestic short-hair cat. Skin stretchers were applied to the site of the skin adjacent to mammary glands for 2-4 days before surgery. Cable tension was adjusted every 6-8 hours to elongate the skin and to achieve primary closure of single-stage bilateral mastectomy without tension. Wound closure after single-stage bilateral mastectomy was achieved without tension or major complication in both animals. Use of skin stretchers allows primary closure of single-stage bilateral mastectomy in dogs and cats. © 2017 The American College of Veterinary Surgeons.

Two-stage atlas subset selection in multi-atlas based image segmentation

Energy Technology Data Exchange (ETDEWEB)

Zhao, Tingting, E-mail: tingtingzhao@mednet.ucla.edu; Ruan, Dan, E-mail: druan@mednet.ucla.edu [The Department of Radiation Oncology, University of California, Los Angeles, California 90095 (United States)

2015-06-15

Purpose: Fast growing access to large databases and cloud stored data presents a unique opportunity for multi-atlas based image segmentation and also presents challenges in heterogeneous atlas quality and computation burden. This work aims to develop a novel two-stage method tailored to the special needs in the face of large atlas collection with varied quality, so that high-accuracy segmentation can be achieved with low computational cost. Methods: An atlas subset selection scheme is proposed to substitute a significant portion of the computationally expensive full-fledged registration in the conventional scheme with a low-cost alternative. More specifically, the authors introduce a two-stage atlas subset selection method. In the first stage, an augmented subset is obtained based on a low-cost registration configuration and a preliminary relevance metric; in the second stage, the subset is further narrowed down to a fusion set of desired size, based on full-fledged registration and a refined relevance metric. An inference model is developed to characterize the relationship between the preliminary and refined relevance metrics, and a proper augmented subset size is derived to ensure that the desired atlases survive the preliminary selection with high probability. Results: The performance of the proposed scheme has been assessed with cross validation based on two clinical datasets consisting of manually segmented prostate and brain magnetic resonance images, respectively. The proposed scheme demonstrates comparable end-to-end segmentation performance as the conventional single-stage selection method, but with significant computation reduction. Compared with the alternative computation reduction method, their scheme improves the mean and medium Dice similarity coefficient value from (0.74, 0.78) to (0.83, 0.85) and from (0.82, 0.84) to (0.95, 0.95) for prostate and corpus callosum segmentation, respectively, with statistical significance. Conclusions: The authors

Two-stage atlas subset selection in multi-atlas based image segmentation.

Science.gov (United States)

Zhao, Tingting; Ruan, Dan

2015-06-01

Fast growing access to large databases and cloud stored data presents a unique opportunity for multi-atlas based image segmentation and also presents challenges in heterogeneous atlas quality and computation burden. This work aims to develop a novel two-stage method tailored to the special needs in the face of large atlas collection with varied quality, so that high-accuracy segmentation can be achieved with low computational cost. An atlas subset selection scheme is proposed to substitute a significant portion of the computationally expensive full-fledged registration in the conventional scheme with a low-cost alternative. More specifically, the authors introduce a two-stage atlas subset selection method. In the first stage, an augmented subset is obtained based on a low-cost registration configuration and a preliminary relevance metric; in the second stage, the subset is further narrowed down to a fusion set of desired size, based on full-fledged registration and a refined relevance metric. An inference model is developed to characterize the relationship between the preliminary and refined relevance metrics, and a proper augmented subset size is derived to ensure that the desired atlases survive the preliminary selection with high probability. The performance of the proposed scheme has been assessed with cross validation based on two clinical datasets consisting of manually segmented prostate and brain magnetic resonance images, respectively. The proposed scheme demonstrates comparable end-to-end segmentation performance as the conventional single-stage selection method, but with significant computation reduction. Compared with the alternative computation reduction method, their scheme improves the mean and medium Dice similarity coefficient value from (0.74, 0.78) to (0.83, 0.85) and from (0.82, 0.84) to (0.95, 0.95) for prostate and corpus callosum segmentation, respectively, with statistical significance. The authors have developed a novel two-stage atlas

Two-stage atlas subset selection in multi-atlas based image segmentation

International Nuclear Information System (INIS)

Zhao, Tingting; Ruan, Dan

2015-01-01

Purpose: Fast growing access to large databases and cloud stored data presents a unique opportunity for multi-atlas based image segmentation and also presents challenges in heterogeneous atlas quality and computation burden. This work aims to develop a novel two-stage method tailored to the special needs in the face of large atlas collection with varied quality, so that high-accuracy segmentation can be achieved with low computational cost. Methods: An atlas subset selection scheme is proposed to substitute a significant portion of the computationally expensive full-fledged registration in the conventional scheme with a low-cost alternative. More specifically, the authors introduce a two-stage atlas subset selection method. In the first stage, an augmented subset is obtained based on a low-cost registration configuration and a preliminary relevance metric; in the second stage, the subset is further narrowed down to a fusion set of desired size, based on full-fledged registration and a refined relevance metric. An inference model is developed to characterize the relationship between the preliminary and refined relevance metrics, and a proper augmented subset size is derived to ensure that the desired atlases survive the preliminary selection with high probability. Results: The performance of the proposed scheme has been assessed with cross validation based on two clinical datasets consisting of manually segmented prostate and brain magnetic resonance images, respectively. The proposed scheme demonstrates comparable end-to-end segmentation performance as the conventional single-stage selection method, but with significant computation reduction. Compared with the alternative computation reduction method, their scheme improves the mean and medium Dice similarity coefficient value from (0.74, 0.78) to (0.83, 0.85) and from (0.82, 0.84) to (0.95, 0.95) for prostate and corpus callosum segmentation, respectively, with statistical significance. Conclusions: The authors

A Concept of Two-Stage-To-Orbit Reusable Launch Vehicle

Science.gov (United States)

Yang, Yong; Wang, Xiaojun; Tang, Yihua

2002-01-01

Reusable Launch Vehicle (RLV) has a capability of delivering a wide rang of payload to earth orbit with greater reliability, lower cost, more flexibility and operability than any of today's launch vehicles. It is the goal of future space transportation systems. Past experience on single stage to orbit (SSTO) RLVs, such as NASA's NASP project, which aims at developing an rocket-based combined-cycle (RBCC) airplane and X-33, which aims at developing a rocket RLV, indicates that SSTO RLV can not be realized in the next few years based on the state-of-the-art technologies. This paper presents a concept of all rocket two-stage-to-orbit (TSTO) reusable launch vehicle. The TSTO RLV comprises an orbiter and a booster stage. The orbiter is mounted on the top of the booster stage. The TSTO RLV takes off vertically. At the altitude about 50km the booster stage is separated from the orbiter, returns and lands by parachutes and airbags, or lands horizontally by means of its own propulsion system. The orbiter continues its ascent flight and delivers the payload into LEO orbit. After completing orbit mission, the orbiter will reenter into the atmosphere, automatically fly to the ground base and finally horizontally land on the runway. TSTO RLV has less technology difficulties and risk than SSTO, and maybe the practical approach to the RLV in the near future.

High-speed double-disc TMP [thermomechanical pulp] from northern and southern softwoods: One or two refining stages

Energy Technology Data Exchange (ETDEWEB)

Sabourin, M.J. (Andritz Sprout-Bauer, Inc., Springfield, OH (United States)); Cort, J.B.; Musselman, R.L. (Andritz Sprout-Bauer, Inc., Muncy, PA (United States))

1994-01-01

Pilot-plant studies were carried out to evaluate one- and two-stage high-speed refining processes for production of thermomechanical pulp (TMP) at minimal energy consumption. Both northern (black spruce/balsam fir) and southern (lobolly pine) wood species were tested. Preliminary results indicate both one- and two-stage high-speed refining are suitable for the production of TMP from spruce and fir. Single-stage, high-speed refining of spruce/fir resulted in over 25% energy savings compared to conventional TMP production. The resulting TMP had improved optical and shive content properties, with slightly reduced pulp strength and long fiber content. Two stages of refining were necessary to optimize pulp quality from the lobolly pine furnish. A 15% energy reduction was obtained when comparing high-speed and conventional TMP pulping of lobolly pine at similar operating conditions. The high-speed pine TMP had comparable bonding strength, shive content, and lower tear than conventional two-stage lobolly pine TMP. 14 refs., 11 figs., 6 tabs.

Tidal volume single breath washout of two tracer gases--a practical and promising lung function test.

Directory of Open Access Journals (Sweden)

Florian Singer

Full Text Available BACKGROUND: Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI, which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW of sulfur hexafluoride (SF(6 and helium (He using an ultrasonic flowmeter (USFM. METHODS: The tracer gas mixture contained 5% SF(6 and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC, were determined in seven subjects performing three SBW 24 hours apart. RESULTS: USFM reliably measured MM during all SBW tests (n = 60. MM from USFM reflected SF(6 and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. CONCLUSION: The USFM accurately measured relative changes in SF(6 and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF(6 and He washout patterns during tidal breathing.

Tidal Volume Single Breath Washout of Two Tracer Gases - A Practical and Promising Lung Function Test

Science.gov (United States)

Singer, Florian; Stern, Georgette; Thamrin, Cindy; Fuchs, Oliver; Riedel, Thomas; Gustafsson, Per; Frey, Urs; Latzin, Philipp

2011-01-01

Background Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF6) and helium (He) using an ultrasonic flowmeter (USFM). Methods The tracer gas mixture contained 5% SF6 and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. Results USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF6 and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. Conclusion The USFM accurately measured relative changes in SF6 and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF6 and He washout patterns during tidal breathing. PMID:21423739

Tidal volume single breath washout of two tracer gases--a practical and promising lung function test.

Science.gov (United States)

Singer, Florian; Stern, Georgette; Thamrin, Cindy; Fuchs, Oliver; Riedel, Thomas; Gustafsson, Per; Frey, Urs; Latzin, Philipp

2011-03-10

Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF(6)) and helium (He) using an ultrasonic flowmeter (USFM). The tracer gas mixture contained 5% SF(6) and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF(6) and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. The USFM accurately measured relative changes in SF(6) and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF(6) and He washout patterns during tidal breathing.

Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process

DEFF Research Database (Denmark)

Luo, Gang; Xie, Li; Zhou, Qi

2011-01-01

The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single......:12 to 1:14, 6.7%, more energy could be obtained. Microbial community analysis indicated that the dominant bacterial species were different in the hydrogen reactors (Thermoanaerobacterium thermosaccharolyticum-like species) and methane reactors (Clostridium thermocellum-like species). The changes...

A novel flow sensor based on resonant sensing with two-stage microleverage mechanism

Science.gov (United States)

Yang, B.; Guo, X.; Wang, Q. H.; Lu, C. F.; Hu, D.

2018-04-01

The design, simulation, fabrication, and experiments of a novel flow sensor based on resonant sensing with a two-stage microleverage mechanism are presented in this paper. Different from the conventional detection methods for flow sensors, two differential resonators are adopted to implement air flow rate transformation through two-stage leverage magnification. The proposed flow sensor has a high sensitivity since the adopted two-stage microleverage mechanism possesses a higher amplification factor than a single-stage microleverage mechanism. The modal distribution and geometric dimension of the two-stage leverage mechanism and hair are analyzed and optimized by Ansys simulation. A digital closed-loop driving technique with a phase frequency detector-based coordinate rotation digital computer algorithm is implemented for the detection and locking of resonance frequency. The sensor fabricated by the standard deep dry silicon on a glass process has a device dimension of 5100 μm (length) × 5100 μm (width) × 100 μm (height) with a hair diameter of 1000 μm. The preliminary experimental results demonstrate that the maximal mechanical sensitivity of the flow sensor is approximately 7.41 Hz/(m/s)2 at a resonant frequency of 22 kHz for the hair height of 9 mm and increases by 2.42 times as hair height extends from 3 mm to 9 mm. Simultaneously, a detection-limit of 3.23 mm/s air flow amplitude at 60 Hz is confirmed. The proposed flow sensor has great application prospects in the micro-autonomous system and technology, self-stabilizing micro-air vehicles, and environmental monitoring.

Single-stage MPPT control realization for Aalborg inverter in photovoltaic system

DEFF Research Database (Denmark)

Zhang, Shuai; Wu, Weimin; Wang, Houqing

2017-01-01

In this paper, the single-stage Maximum Power Point Tracking (MPPT) control strategy for the Aalborg photovoltaic inverter is presented. Aalborg inverter has many advantages, such as high efficiency, wide range of input voltage, minimum voltage drop of the filtering inductors, etc. Nevertheless......, it is essentially a “half-bridge” inverter with two input sources, where one source works in MPPT mode, the other is out of control. If without the reasonable parameter design and the proper control, the bus-voltage of this inverter may change greatly, resulting in the serious power oscillation around maximum power...

Droop Control with Improved Disturbance Adaption for PV System with Two Power Conversion Stages

DEFF Research Database (Denmark)

Liu, Hongpeng; Loh, Poh Chiang; Wang, Xiongfei

2016-01-01

with no or insufficient storage for cushioning climatic changes. In addition, most droop-controlled literatures have assumed a single dc-ac inverter with its input dc source fixed. Front-end dc-dc converter added to a two-stage photovoltaic (PV) system has therefore usually been ignored. To address these unresolved...

A high-order positivity-preserving single-stage single-step method for the ideal magnetohydrodynamic equations

Science.gov (United States)

Christlieb, Andrew J.; Feng, Xiao; Seal, David C.; Tang, Qi

2016-07-01

We propose a high-order finite difference weighted ENO (WENO) method for the ideal magnetohydrodynamics (MHD) equations. The proposed method is single-stage (i.e., it has no internal stages to store), single-step (i.e., it has no time history that needs to be stored), maintains a discrete divergence-free condition on the magnetic field, and has the capacity to preserve the positivity of the density and pressure. To accomplish this, we use a Taylor discretization of the Picard integral formulation (PIF) of the finite difference WENO method proposed in Christlieb et al. (2015) [23], where the focus is on a high-order discretization of the fluxes (as opposed to the conserved variables). We use the version where fluxes are expanded to third-order accuracy in time, and for the fluid variables space is discretized using the classical fifth-order finite difference WENO discretization. We use constrained transport in order to obtain divergence-free magnetic fields, which means that we simultaneously evolve the magnetohydrodynamic (that has an evolution equation for the magnetic field) and magnetic potential equations alongside each other, and set the magnetic field to be the (discrete) curl of the magnetic potential after each time step. In this work, we compute these derivatives to fourth-order accuracy. In order to retain a single-stage, single-step method, we develop a novel Lax-Wendroff discretization for the evolution of the magnetic potential, where we start with technology used for Hamilton-Jacobi equations in order to construct a non-oscillatory magnetic field. The end result is an algorithm that is similar to our previous work Christlieb et al. (2014) [8], but this time the time stepping is replaced through a Taylor method with the addition of a positivity-preserving limiter. Finally, positivity preservation is realized by introducing a parameterized flux limiter that considers a linear combination of high and low-order numerical fluxes. The choice of the free

A stage is a stage is a stage: a direct comparison of two scoring systems.

Science.gov (United States)

Dawson, Theo L

2003-09-01

L. Kohlberg (1969) argued that his moral stages captured a developmental sequence specific to the moral domain. To explore that contention, the author compared stage assignments obtained with the Standard Issue Scoring System (A. Colby & L. Kohlberg, 1987a, 1987b) and those obtained with a generalized content-independent stage-scoring system called the Hierarchical Complexity Scoring System (T. L. Dawson, 2002a), on 637 moral judgment interviews (participants' ages ranged from 5 to 86 years). The correlation between stage scores produced with the 2 systems was .88. Although standard issue scoring and hierarchical complexity scoring often awarded different scores up to Kohlberg's Moral Stage 2/3, from his Moral Stage 3 onward, scores awarded with the two systems predominantly agreed. The author explores the implications for developmental research.

Structure, texture, and mechanical properties of an MA2-1hp magnesium alloy after two-stage equal-channel angular pressing and intermediate annealing

Science.gov (United States)

Serebryany, V. N.; Perezhogin, V. Yu.; Raab, G. I.; Kopylov, V. I.; Tabachkova, N. Yu.; Sirotinkin, V. P.; Dobatkin, S. V.

2015-01-01

The effect of two-stage equal-channel angular pressing (ECAP) on the microstructure, the texture, and the mechanical properties of an MA2-1hp magnesium alloy is analyzed. ECAP leads to the formation of a submicrocrystalline structure with an average grain size of 640 nm, which includes Mg17Al12 phase particles with an average grain size of 240 nm and a volume fracture of 5.5%. A scattered tilted basal texture forms after ECAP, and its experimental pole figures are used for calculating orientation distribution functions and determining the volume fractions of the main orientations and the Schmid factors for different deformation systems. An increased activation of basal slip is found after both the first and the second stages of ECAP. As a result of two-stage ECAP, the strength properties of the alloy that correspond to the minimum acceptable values achieved by direct compression are obtained. Ductility is 44 and 18% after the first stage of ECAP plus subsequent annealing and after the second stage, respectively, which is almost four and two times higher than the initial value. The resulting strength mechanical properties of the alloy after the first and the second ECAP stages are analyzed using the Hall-Petch relation.

Opposed piston linear compressor driven two-stage Stirling Cryocooler for cooling of IR sensors in space application

Science.gov (United States)

Bhojwani, Virendra; Inamdar, Asif; Lele, Mandar; Tendolkar, Mandar; Atrey, Milind; Bapat, Shridhar; Narayankhedkar, Kisan

2017-04-01

A two-stage Stirling Cryocooler has been developed and tested for cooling IR sensors in space application. The concept uses an opposed piston linear compressor to drive the two-stage Stirling expander. The configuration used a moving coil linear motor for the compressor as well as for the expander unit. Electrical phase difference of 80 degrees was maintained between the voltage waveforms supplied to the compressor motor and expander motor. The piston and displacer surface were coated with Rulon an anti-friction material to ensure oil less operation of the unit. The present article discusses analysis results, features of the cryocooler and experimental tests conducted on the developed unit. The two-stages of Cryo-cylinder and the expander units were manufactured from a single piece to ensure precise alignment between the two-stages. Flexure bearings were used to suspend the piston and displacer about its mean position. The objective of the work was to develop a two-stage Stirling cryocooler with 2 W at 120 K and 0.5 W at 60 K cooling capacity for the two-stages and input power of less than 120 W. The Cryocooler achieved a minimum temperature of 40.7 K at stage 2.

Two-stage thermal/nonthermal waste treatment process

International Nuclear Information System (INIS)

Rosocha, L.A.; Anderson, G.K.; Coogan, J.J.; Kang, M.; Tennant, R.A.; Wantuck, P.J.

1993-01-01

An innovative waste treatment technology is being developed in Los Alamos to address the destruction of hazardous organic wastes. The technology described in this report uses two stages: a packed bed reactor (PBR) in the first stage to volatilize and/or combust liquid organics and a silent discharge plasma (SDP) reactor to remove entrained hazardous compounds in the off-gas to even lower levels. We have constructed pre-pilot-scale PBR-SDP apparatus and tested the two stages separately and in combined modes. These tests are described in the report

Adaptive Urban Stormwater Management Using a Two-stage Stochastic Optimization Model

Science.gov (United States)

Hung, F.; Hobbs, B. F.; McGarity, A. E.

2014-12-01

In many older cities, stormwater results in combined sewer overflows (CSOs) and consequent water quality impairments. Because of the expense of traditional approaches for controlling CSOs, cities are considering the use of green infrastructure (GI) to reduce runoff and pollutants. Examples of GI include tree trenches, rain gardens, green roofs, and rain barrels. However, the cost and effectiveness of GI are uncertain, especially at the watershed scale. We present a two-stage stochastic extension of the Stormwater Investment Strategy Evaluation (StormWISE) model (A. McGarity, JWRPM, 2012, 111-24) to explicitly model and optimize these uncertainties in an adaptive management framework. A two-stage model represents the immediate commitment of resources ("here & now") followed by later investment and adaptation decisions ("wait & see"). A case study is presented for Philadelphia, which intends to extensively deploy GI over the next two decades (PWD, "Green City, Clean Water - Implementation and Adaptive Management Plan," 2011). After first-stage decisions are made, the model updates the stochastic objective and constraints (learning). We model two types of "learning" about GI cost and performance. One assumes that learning occurs over time, is automatic, and does not depend on what has been done in stage one (basic model). The other considers learning resulting from active experimentation and learning-by-doing (advanced model). Both require expert probability elicitations, and learning from research and monitoring is modelled by Bayesian updating (as in S. Jacobi et al., JWRPM, 2013, 534-43). The model allocates limited financial resources to GI investments over time to achieve multiple objectives with a given reliability. Objectives include minimizing construction and O&M costs; achieving nutrient, sediment, and runoff volume targets; and community concerns, such as aesthetics, CO2 emissions, heat islands, and recreational values. CVaR (Conditional Value at Risk) and

Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.

Science.gov (United States)

Warriner, David R; Brown, Alistair G; Varma, Susheel; Sheridan, Paul J; Lawford, Patricia; Hose, David R; Al-Mohammad, Abdallah; Shi, Yubing

2014-01-01

The American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for the classification of heart failure (HF) are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV) pressure-volume (PV) loop data and secondly use the LV PV loop data to create stage specific HF models. A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV), ejection fraction (EF%) decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax). For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails.

Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.

Directory of Open Access Journals (Sweden)

David R Warriner

Full Text Available INTRODUCTION: The American Heart Association (AHA/American College of Cardiology (ACC guidelines for the classification of heart failure (HF are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV pressure-volume (PV loop data and secondly use the LV PV loop data to create stage specific HF models. METHODS AND RESULTS: A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV, ejection fraction (EF% decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax. CONCLUSIONS: For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails.

Comparison of Oone-Stage Free Gracilis Muscle Flap With Two-Stage Method in Chronic Facial Palsy

Directory of Open Access Journals (Sweden)

J Ghaffari

2007-08-01

Full Text Available Background:Rehabilitation of facial paralysis is one of the greatest challenges faced by reconstructive surgeons today. The traditional method for treatment of patients with facial palsy is the two-stage free gracilis flap which has a long latency period of between the two stages of surgery.Methods: In this paper, we prospectively compared the results of the one-stage gracilis flap method with the two -stage technique.Results:Out of 41 patients with facial palsy refered to Hazrat-e-Fatemeh Hospital 31 were selected from whom 22 underwent two- stage and 9 one-stage method treatment. The two groups were identical according to age,sex,intensity of illness, duration, and chronicity of illness. Mean duration of follow up was 37 months. There was no significant relation between the two groups regarding the symmetry of face in repose, smiling, whistling and nasolabial folds. Frequency of complications was equal in both groups. The postoperative surgeons and patients' satisfaction were equal in both groups. There was no significant difference between the mean excursion of muscle flap in one-stage (9.8 mm and two-stage groups (8.9 mm. The ratio of contraction of the affected side compared to the normal side was similar in both groups. The mean time of the initial contraction of the muscle flap in the one-stage group (5.5 months had a significant difference (P=0.001 with the two-stage one (6.5 months.The study revealed a highly significant difference (P=0.0001 between the mean waiting period from the first operation to the beginning of muscle contraction in one-stage(5.5 monthsand two-stage groups(17.1 months.Conclusion:It seems that the results and complication of the two methods are the same,but the one-stage method requires less time for facial reanimation,and is costeffective because it saves time and decreases hospitalization costs.

The μ-RWELL: A compact, spark protected, single amplification-stage MPGD

Science.gov (United States)

Poli Lener, M.; Bencivenni, G.; de Olivera, R.; Felici, G.; Franchino, S.; Gatta, M.; Maggi, M.; Morello, G.; Sharma, A.

2016-07-01

In this work we present two innovative architectures of resistive MPGDs based on the WELL-amplification concept: - the micro-Resistive WELL (μ-RWELL) is a compact spark-protected single amplification-stage Micro-Pattern Gas Detector (MPGD). The amplification stage, realized with a structure very similar to a GEM foil (called WELL), is embedded through a resistive layer in the readout board. A cathode electrode, defining the gas conversion/drift gap, completes the detector mechanics. The new architecture, showing an excellent space resolution, 50 μm, is a very compact device, robust against discharges and exhibiting a large gain (>104), simple to construct and easy for engineering and then suitable for large area tracking devices as well as digital calorimeters. - the Fast Timing Micro-pattern (FTM): a new device with an architecture based on a stack of several coupled full-resistive layers where drift and multiplication stages (WELL type) alternate in the structure. The signals from each multiplication stage can be read out from any external readout boards through the capacitive couplings, providing a signal with a gain of 104-105. The main advantage of this new device is the improvement of the timing provided by the competition of the ionization processes in the different drift regions, which can be exploited for fast timing at the high luminosity accelerators (e.g. HL-LHC upgrade) as well as for applications like medical imaging.

Single-Stage Step up/down Driver for Permanent-Magnet Synchronous Machines

Science.gov (United States)

Chen, T. R.; Juan, Y. L.; Huang, C. Y.; Kuo, C. T.

2017-11-01

The two-stage circuit composed of a step up/down dc converter and a three-phase voltage source inverter is usually adopted as the electric vehicle’s motor driver. The conventional topology is more complicated. Additional power loss resulted from twice power conversion would also cause lower efficiency. A single-stage step up/down Permanent-Magnet Synchronous Motor driver for Brushless DC (BLDC) Motor is proposed in this study. The number components and circuit complexity are reduced. The low frequency six-step square-wave control is used to reduce the switching losses. In the proposed topology, only one active switch is gated with a high frequency PWM signal for adjusting the rotation speed. The rotor position signals are fed back to calculate the motor speed for digital close-loop control in a MCU. A 600W prototype circuit is constructed to drive a BLDC motor with rated speed 3000 rpm, and can control the speed of six sections.

Adjuvant therapy in stage I and stage II epithelial ovarian cancer. Results of two prospective randomized trials

International Nuclear Information System (INIS)

Young, R.C.; Walton, L.A.; Ellenberg, S.S.; Homesley, H.D.; Wilbanks, G.D.; Decker, D.G.; Miller, A.; Park, R.; Major, F. Jr.

1990-01-01

About a third of patients with ovarian cancer present with localized disease; despite surgical resection, up to half the tumors recur. Since it has not been established whether adjuvant treatment can benefit such patients, we conducted two prospective, randomized national cooperative trials of adjuvant therapy in patients with localized ovarian carcinoma. All patients underwent surgical resection plus comprehensive staging and, 18 months later, surgical re-exploration. In the first trial, 81 patients with well-differentiated or moderately well differentiated cancers confined to the ovaries (Stages Iai and Ibi) were assigned to receive either no chemotherapy or melphalan (0.2 mg per kilogram of body weight per day for five days, repeated every four to six weeks for up to 12 cycles). After a median follow-up of more than six years, there were no significant differences between the patients given no chemotherapy and those treated with melphalan with respect to either five-year disease-free survival or overall survival. In the second trial, 141 patients with poorly differentiated Stage I tumors or with cancer outside the ovaries but limited to the pelvis (Stage II) were randomly assigned to treatment with either melphalan (in the same regimen as above) or a single intraperitoneal dose of 32P (15 mCi) at the time of surgery. In this trial (median follow-up, greater than 6 years) the outcomes for the two treatment groups were similar with respect to five-year disease-free survival (80 percent in both groups) and overall survival (81 percent with melphalan vs. 78 percent with 32P; P = 0.48). We conclude that in patients with localized ovarian cancer, comprehensive staging at the time of surgical resection can serve to identify those patients (as defined by the first trial) who can be followed without adjuvant chemotherapy

Comparison of bone volume measurements using conventional single and dual energy computed tomography

International Nuclear Information System (INIS)

Kim, Yung Kyoon; Park, Sang Hoon; Kim, Yon Min

2017-01-01

The study examines changes in calcium volume on born by comparing two figures; one is measured by dual energy computed tomography(DECT) followed by applying variation in monochromatic energy selection( keV), material decomposition(MD), and material suppressed iodine(MSI) analysis, and the other is measured by conventional single source computed tomography(CSCT). For this study, based on CSCT images taken by using human mimicked phantom, 70, 100, 140 keV and MSI, MD material calcium weighting( MCW) and MD material iodine weighting(MIW) of DECT were applied respectively. Then calculated calcium volume was converted to Agatston score for comparison. Volume of human mimicked phantom was in inverse proportion to keV. The volume decreased while keV increased(p<0.05). The most similar DECT volumes were reconstructed at 70 keV, the difference was showed 35.8±12.2 for rib, femur (16.1±24.1), pelvis(13.7±18.8), and spine(179.0±61.8). However, the volume of MSI was down for each organ; the volume of rib was 5.55%, femur(76.34%), pelvis(55.16%) and spine(87.58%). The volume of MSI decreased 55.9% for rib, femur(80.7%), pelvis(69.6%) and spine(54.2%) while MD MIW reduced for rib(83.51%), femur(87.68%), pelvis(86.64%), and spine(82.62%). With the results, the study found that outcomes were affected by the method which examiners employed. When using DECT, calcium volume of born dropped with keV increased. It also found that the most similar DECT images were reconstructed at 70 keV. The results of experiments implied that the users of MSI and MD should be cautious of errors as there are big differences in scores between those two methods

Comparison of bone volume measurements using conventional single and dual energy computed tomography

Energy Technology Data Exchange (ETDEWEB)

Kim, Yung Kyoon; Park, Sang Hoon [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Kim, Yon Min [Dept. of Radiotechnology, Wonkwang Health Science University, Iksan (Korea, Republic of)

2017-06-15

The study examines changes in calcium volume on born by comparing two figures; one is measured by dual energy computed tomography(DECT) followed by applying variation in monochromatic energy selection( keV), material decomposition(MD), and material suppressed iodine(MSI) analysis, and the other is measured by conventional single source computed tomography(CSCT). For this study, based on CSCT images taken by using human mimicked phantom, 70, 100, 140 keV and MSI, MD material calcium weighting( MCW) and MD material iodine weighting(MIW) of DECT were applied respectively. Then calculated calcium volume was converted to Agatston score for comparison. Volume of human mimicked phantom was in inverse proportion to keV. The volume decreased while keV increased(p<0.05). The most similar DECT volumes were reconstructed at 70 keV, the difference was showed 35.8±12.2 for rib, femur (16.1±24.1), pelvis(13.7±18.8), and spine(179.0±61.8). However, the volume of MSI was down for each organ; the volume of rib was 5.55%, femur(76.34%), pelvis(55.16%) and spine(87.58%). The volume of MSI decreased 55.9% for rib, femur(80.7%), pelvis(69.6%) and spine(54.2%) while MD MIW reduced for rib(83.51%), femur(87.68%), pelvis(86.64%), and spine(82.62%). With the results, the study found that outcomes were affected by the method which examiners employed. When using DECT, calcium volume of born dropped with keV increased. It also found that the most similar DECT images were reconstructed at 70 keV. The results of experiments implied that the users of MSI and MD should be cautious of errors as there are big differences in scores between those two methods.

The early stages of oxidation of magnesium single crystal surfaces

International Nuclear Information System (INIS)

Hayden, B.E.; Schweizer, E.; Koetz, R.; Bradshaw, A.M.

1981-01-01

The early stages of oxidation of Mg(001) and Mg(100) single crystal surfaces at 300 K have been investigated by LEED, ELS, work function and ellipsometric measurements. A sharp decrease in work function on both surfaces during the first 12 L exposure indicates the incorporation of oxygen in the earliest stages of the interaction. The incorporated oxygen on Mg(001) gives rise to a broadening of the integral order LEED spots for an exposure 3 L. (orig.)

Ripple Mitigation with Improved Line-Load Transients Response in Two-Stage DC-DC-AC Converter

DEFF Research Database (Denmark)

Gautam, Aditya R.; Gaurav, Kumar; Guerrero, Josep M.

2018-01-01

. The front-end boost converter in the considered two-stage converter interfaces a battery bank and single phase inverter fed loads. The control shapes the output impedance of boost converter to reduce the ripple component at battery input. Secondly, the proposed controller achieves good dynamic performance...

Single-stage soft tissue reconstruction and orbital fracture repair for complex facial injuries.

Science.gov (United States)

Wu, Peng Sen; Matoo, Reshvin; Sun, Hong; Song, Li Yuan; Kikkawa, Don O; Lu, Wei

2017-02-01

Orbital fractures with open periorbital wounds cause significant morbidity. Timing of debridement with fracture repair and soft tissue reconstruction is controversial. This study focuses on the efficacy of early single-stage repair in combined bony and soft tissue injuries. Retrospective review. Twenty-three patients with combined open soft tissue wounds and orbital fractures were studied for single-stage orbital reconstruction and periorbital soft tissue repair. Inclusion criteria were open soft tissue wounds with clinical and radiographic evidence of orbital fractures and repair performed within 48 h after injury. Surgical complications and reconstructive outcomes were assessed over 6 months. The main outcome measures were enophthalmos, pre- and post-CT imaging of orbits, scar evaluation, presence of diplopia, and eyelid position. Enophthalmos was corrected in 16/19 cases and improved in 3/19 cases. 3D reconstruction of CT images showed markedly improved orbital alignment with objective measurements of the optic foramen to cornea distance (mm) in reconstructed orbits relative to intact orbits of 0.66, 95% confidence interval [CI] (lower 0.33, upper 0.99) mm. The mean baseline of Stony Brook Scar Evaluation Scale was 0.6, 95%CI (0.30-0.92), and for 6 months, the mean score was 3.4, 95%CI (3.05-3.73). Residual diplopia in secondary gazes was present in two patients; one patient had ectropion. Complications included one case of local wound infection. An early single-stage repair of combined soft tissue and orbital fractures yields satisfactory functional and aesthetic outcomes. Complications are low and likely related to trauma severity. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Control scheme towards enhancing power quality and operational efficiency of single-phase two-stage grid-connected photovoltaic systems

Directory of Open Access Journals (Sweden)

Mahmoud Salem

2015-12-01

Full Text Available Achieving high reliable grid-connected photovoltaic (PV systems with high power quality and high operation efficiency is highly required for distributed generation units. A double grid-frequency voltage ripple is found on the dc-link voltage in single-phase photovoltaic grid-connected systems due to the unbalance of the instantaneous dc input and ac output powers. This voltage ripple has undesirable effects on the power quality and operational efficiency of the whole system. Harmonic distortion in the injected current to the grid is one of the problems caused by this double grid-frequency voltage ripple. The double grid frequency ripple propagates to the PV voltage and current which disturb the extracted maximum power from the PV array. This paper introduces intelligent solutions towards mitigate the side effects of the double grid-frequency voltage ripple on the transferred power quality and the operational efficiency of single-phase two-stage grid-connected PV system. The proposed system has three control loops: MPPT control loop, dc-link voltage control loop and inverter current control loop. Solutions are introduced for all the three control loops in the system. The current controller cancels the dc-link voltage effect on the total harmonic distortion of the output current. The dc-link voltage controller is designed to generate a ripple free reference current signal that leads to enhance the quality of the output power. Also a modified MPPT controller is proposed to optimize the extracted power from the PV array. Simulation results show that higher injected power quality is achieved and higher efficiency of the overall system is realized.

Confidence interval estimation of the difference between two sensitivities to the early disease stage.

Science.gov (United States)

Dong, Tuochuan; Kang, Le; Hutson, Alan; Xiong, Chengjie; Tian, Lili

2014-03-01

Although most of the statistical methods for diagnostic studies focus on disease processes with binary disease status, many diseases can be naturally classified into three ordinal diagnostic categories, that is normal, early stage, and fully diseased. For such diseases, the volume under the ROC surface (VUS) is the most commonly used index of diagnostic accuracy. Because the early disease stage is most likely the optimal time window for therapeutic intervention, the sensitivity to the early diseased stage has been suggested as another diagnostic measure. For the purpose of comparing the diagnostic abilities on early disease detection between two markers, it is of interest to estimate the confidence interval of the difference between sensitivities to the early diseased stage. In this paper, we present both parametric and non-parametric methods for this purpose. An extensive simulation study is carried out for a variety of settings for the purpose of evaluating and comparing the performance of the proposed methods. A real example of Alzheimer's disease (AD) is analyzed using the proposed approaches. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

International Nuclear Information System (INIS)

Ariunbaatar, Javkhlan; Scotto Di Perta, Ester; Panico, Antonio; Frunzo, Luigi; Esposito, Giovanni; Lens, Piet N.L.; Pirozzi, Francesco

2015-01-01

Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC 50 of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid

Staging of gastric adenocarcinoma using two-phase spiral CT: correlation with pathologic staging

International Nuclear Information System (INIS)

Seo, Tae Seok; Lee, Dong Ho; Ko, Young Tae; Lim, Joo Won

1998-01-01

To correlate the preoperative staging of gastric adenocarcinoma using two-phase spiral CT with pathologic staging. One hundred and eighty patients with gastric cancers confirmed during surgery underwent two-phase spiral CT, and were evaluated retrospectively. CT scans were obtained in the prone position after ingestion of water. Scans were performed 35 and 80 seconds after the start of infusion of 120mL of non-ionic contrast material with the speed of 3mL/sec. Five mm collimation, 7mm/sec table feed and 5mm reconstruction interval were used. T-and N-stage were determined using spiral CT images, without knowledge of the pathologic results. Pathologic staging was later compared with CT staging. Pathologic T-stage was T1 in 70 cases(38.9%), T2 in 33(18.3%), T3 in 73(40.6%), and T4 in 4(2.2%). Type-I or IIa elevated lesions accouted for 10 of 70 T1 cases(14.3%) and flat or depressed lesions(type IIb, IIc, or III) for 60(85.7%). Pathologic N-stage was NO in 85 cases(47.2%), N1 in 42(23.3%), N2 in 31(17.2%), and N3 in 22(12,2%). The detection rate of early gastric cancer using two-phase spiral CT was 100.0%(10 of 10 cases) among elevated lesions and 78.3%(47 of 60 cases) among flat or depressed lesions. With regard to T-stage, there was good correlation between CT image and pathology in 86 of 180 cases(47.8%). Overstaging occurred in 23.3%(42 of 180 cases) and understaging in 28.9%(52 of 180 cases). With regard to N-stage, good correlation between CT image and pathology was noted in 94 of 180 cases(52.2%). The rate of understaging(31.7%, 57 of 180 cases) was higher than that of overstaging(16.1%, 29 of 180 cases)(p<0.001). The detection rate of early gastric cancer using two-phase spiral CT was 81.4%, and there was no significant difference in detectability between elevated and depressed lesions. Two-phase spiral CT for determing the T-and N-stage of gastric cancer was not effective;it was accurate in abont 50% of cases understaging tended to occur.=20

Nitrite reduction and methanogenesis in a single-stage UASB reactor.

Science.gov (United States)

Borges, L I; López-Vazquez, C M; García, H; van Lier, J B

2015-01-01

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO(2)(-)-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO(2)(-)-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO(2)(-)-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO(2)(-) reduction to N₂. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

Frequency analysis of a two-stage planetary gearbox using two different methodologies

Science.gov (United States)

Feki, Nabih; Karray, Maha; Khabou, Mohamed Tawfik; Chaari, Fakher; Haddar, Mohamed

2017-12-01

This paper is focused on the characterization of the frequency content of vibration signals issued from a two-stage planetary gearbox. To achieve this goal, two different methodologies are adopted: the lumped-parameter modeling approach and the phenomenological modeling approach. The two methodologies aim to describe the complex vibrations generated by a two-stage planetary gearbox. The phenomenological model describes directly the vibrations as measured by a sensor fixed outside the fixed ring gear with respect to an inertial reference frame, while results from a lumped-parameter model are referenced with respect to a rotating frame and then transferred into an inertial reference frame. Two different case studies of the two-stage planetary gear are adopted to describe the vibration and the corresponding spectra using both models. Each case presents a specific geometry and a specific spectral structure.

Thermodynamics analysis of a modified dual-evaporator CO2 transcritical refrigeration cycle with two-stage ejector

International Nuclear Information System (INIS)

Bai, Tao; Yan, Gang; Yu, Jianlin

2015-01-01

In this paper, a modified dual-evaporator CO 2 transcritical refrigeration cycle with two-stage ejector (MDRC) is proposed. In MDRC, the two-stage ejector are employed to recover the expansion work from cycle throttling processes and enhance the system performance and obtain dual-temperature refrigeration simultaneously. The effects of some key parameters on the thermodynamic performance of the modified cycle are theoretically investigated based on energetic and exergetic analyses. The simulation results for the modified cycle show that two-stage ejector exhibits more effective system performance improvement than the single ejector in CO 2 dual-temperature refrigeration cycle, and the improvements of the maximum system COP (coefficient of performance) and system exergy efficiency could reach 37.61% and 31.9% over those of the conventional dual-evaporator cycle under the given operating conditions. The exergetic analysis for each component at optimum discharge pressure indicates that the gas cooler, compressor, two-stage ejector and expansion valves contribute main portion to the total system exergy destruction, and the exergy destruction caused by the two-stage ejector could amount to 16.91% of the exergy input. The performance characteristics of the proposed cycle show its promise in dual-evaporator refrigeration system. - Highlights: • Two-stage ejector is used in dual-evaporator CO 2 transcritical refrigeration cycle. • Energetic and exergetic methods are carried out to analyze the system performance. • The modified cycle could obtain dual-temperature refrigeration simultaneously. • Two-stage ejector could effectively improve system COP and exergy efficiency

Performance Improvement for Two-Stage Single-Phase Grid-Connected Converters Using a Fast DC Bus Control Scheme and a Novel Synchronous Frame Current Controller

Directory of Open Access Journals (Sweden)

Bingzhang Li

2017-03-01

Full Text Available Two-stage single-phase grid-connected converters are widely used in renewable energy applications. Due to the presence of a second harmonic ripple across the DC bus voltage, it is very challenging to design the DC bus voltage control scheme in single-phase grid-connected inverters. The DC bus voltage controller must filter the ripple and balance a tradeoff between low harmonic distortion and high bandwidth. This paper presents a fast DC bus voltage controller, which uses a second order digital finite impulse response (FIR notch filter in conjunction with input power feedforward scheme to ensure the steady-state and dynamic performance. To gain the input power without extra hardware, a Kalman filter is incorporated to estimate the DC bus input current. At the same time, a modulation compensation strategy is implemented to eliminate the nonlinearity of the grid current control loop, which is caused by the DC bus voltage ripple. Moreover, a novel synchronous frame current controller for single-phase systems is also introduced, and its equivalent model in stationary frame has been derived. Simulation and experimental results are provided to verify the effective of the proposed control scheme.

State of the art in fluid and volume therapy : A user-friendly staged concept. English version.

Science.gov (United States)

Rehm, M; Hulde, N; Kammerer, T; Meidert, A S; Hofmann-Kiefer, K

2017-04-10

Adequate intraoperative infusion therapy is essential for the perioperative outcome of a patient. Both hypo- and hypervolemia can lead to an increased rate of perioperative complications and to a worse outcome. Perioperative infusion therapy should therefore be needs-based. The primary objective is the maintenance of preoperative normovolemia using a rational infusion strategy. Perioperative fluid losses should be differentiated from volume losses due to surgical bleeding or protein losses into the interstitial space. Fluid loss via urine excretion or insensible perspiration (0.5-1.0 ml/kg/h) should be replaced with balanced, isooncotic, crystalloid infusion solutions in a ratio of 1:1. Volume therapy stage 1: intraoperative volume losses up to a blood loss corresponding to 20% of the patient's total blood volume are compensated for by balanced crystalloids in a ratio of 4-5:1. Stage 2: blood losses exceeding this level are to be treated with isooncotic colloids (preferably balanced) in a 1:1 ratio. In this regard taking into consideration the contraindications, e. g., sepsis, burns, critical illness (usually patients in the intensive care unit), impaired renal function or renal replacement therapy, intracranial hemorrhage, or severe coagulopathy, artificial colloids such as hydroxyethyl starch (HES) can be used perioperatively for volume replacement. Stage 3: if an allogeneic blood transfusion is indicated, blood and blood products are applied in a differentiated manner.

Left ventricular volume determination from single-photon emission computed tomography

International Nuclear Information System (INIS)

Bunker, S.R.; Hartshorne, M.F.; Schmidt, W.P.; Cawthon, M.A.; Karl, R.D. Jr.; Bauman, J.M.; Howard, W.H. III; Rubal, B.J.

1985-01-01

To compare the accuracy of single-photon emission computed tomography (SPECT) with that of contrast cineangiography in measuring left ventricular end-diastolic volume, 25 consecutive patients undergoing catheterizaiton for coronary artery or valvular heart disease were first evaluated scintigraphically. SPECT volume values showed a high degree of correlation with those determined by angiography with a standard error of the estimate of 23 ml. SPECT offers a highly accurate and essentially noninvasive method for measuring chamber volumes that is independent of geometric assumptions about ventricular configuration and chest wall attenuation and does not require blood sample counting

Left ventricular volume determination from single-photon emission computed tomography

Energy Technology Data Exchange (ETDEWEB)

Bunker, S.R.; Hartshorne, M.F.; Schmidt, W.P.; Cawthon, M.A.; Karl, R.D. Jr.; Bauman, J.M.; Howard, W.H. III; Rubal, B.J.

1985-02-01

To compare the accuracy of single-photon emission computed tomography (SPECT) with that of contrast cineangiography in measuring left ventricular end-diastolic volume, 25 consecutive patients undergoing catheterizaiton for coronary artery or valvular heart disease were first evaluated scintigraphically. SPECT volume values showed a high degree of correlation with those determined by angiography with a standard error of the estimate of 23 ml. SPECT offers a highly accurate and essentially noninvasive method for measuring chamber volumes that is independent of geometric assumptions about ventricular configuration and chest wall attenuation and does not require blood sample counting.

Studying the effect of over-modulation on the output voltage of three-phase single-stage grid-connected boost inverter

Directory of Open Access Journals (Sweden)

A. Abbas Elserougi

2013-09-01

Full Text Available Voltage boosting is very essential issue in renewable-energy fed applications. The classical two-stage power conversion process is typically used to interface the renewable energy sources to the grid. For better efficiency, single-stage inverters are recommended. In this paper, the performance of single-stage three-phase grid-connected boost inverter is investigated when its gain is extended by employing over-modulation technique. Using of over-modulation is compared with the employment of third order harmonic injection. The latter method can increase the inverter gain by 15% without distorting the inverter output voltage. The performance of extended gain grid-connected boost inverter is also tested during normal operation as well as in the presence of grid side disturbances. Simulation and experimental results are satisfactory.

Many-Objective Particle Swarm Optimization Using Two-Stage Strategy and Parallel Cell Coordinate System.

Science.gov (United States)

Hu, Wang; Yen, Gary G; Luo, Guangchun

2017-06-01

It is a daunting challenge to balance the convergence and diversity of an approximate Pareto front in a many-objective optimization evolutionary algorithm. A novel algorithm, named many-objective particle swarm optimization with the two-stage strategy and parallel cell coordinate system (PCCS), is proposed in this paper to improve the comprehensive performance in terms of the convergence and diversity. In the proposed two-stage strategy, the convergence and diversity are separately emphasized at different stages by a single-objective optimizer and a many-objective optimizer, respectively. A PCCS is exploited to manage the diversity, such as maintaining a diverse archive, identifying the dominance resistant solutions, and selecting the diversified solutions. In addition, a leader group is used for selecting the global best solutions to balance the exploitation and exploration of a population. The experimental results illustrate that the proposed algorithm outperforms six chosen state-of-the-art designs in terms of the inverted generational distance and hypervolume over the DTLZ test suite.

A Two-Stage Layered Mixture Experiment Design for a Nuclear Waste Glass Application-Part 1

International Nuclear Information System (INIS)

Cooley, Scott K.; Piepel, Gregory F.; Gan, Hao; Kot, Wing; Pegg, Ian L.

2003-01-01

A layered experimental design involving mixture variables was generated to support developing property-composition models for high-level waste (HLW) glasses. The design was generated in two stages, each having unique characteristics. Each stage used a layered design having an outer layer, an inner layer, a center point, and some replicates. The layers were defined by single- and multi-variable constraints. The first stage involved 15 glass components treated as mixture variables. For each layer, vertices were generated and optimal design software was used to select alternative subsets of vertices and calculate design optimality measures. Two partial quadratic mixture models, containing 25 terms for the outer layer and 30 terms for the inner layer, were the basis for the optimal design calculations. Distributions of predicted glass property values were plotted and evaluated for the alternative subsets of vertices. Based on the optimality measures and the predicted property distributions, a ''best'' subset of vertices was selected for each layer to form a layered design for the first stage. The design for the second stage was selected to augment the first-stage design. The discussion of the second-stage design begins in this Part 1 and is continued in Part 2 (Cooley and Piepel, 2003b)

Two-stage precipitation of neptunium (IV) oxalate

International Nuclear Information System (INIS)

Luerkens, D.W.

1983-07-01

Neptunium (IV) oxalate was precipitated using a two-stage precipitation system. A series of precipitation experiments was used to identify the significant process variables affecting precipitate characteristics. Process variables tested were input concentrations, solubility conditions in the first stage precipitator, precipitation temperatures, and residence time in the first stage precipitator. A procedure has been demonstrated that produces neptunium (IV) oxalate particles that filter well and readily calcine to the oxide

Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

Energy Technology Data Exchange (ETDEWEB)

Ariunbaatar, Javkhlan, E-mail: jaka@unicas.it [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Scotto Di Perta, Ester [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy); Panico, Antonio [Telematic University PEGASO, Piazza Trieste e Trento, 48, 80132 Naples (Italy); Frunzo, Luigi [Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, Via Claudio, 21, 80125 Naples (Italy); Esposito, Giovanni [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); Lens, Piet N.L. [UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Pirozzi, Francesco [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy)

2015-04-15

Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC{sub 50} of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid.

Quantified measurement of brain blood volume: comparative evaluations between the single photon emission computer tomography and the positron computer tomography

International Nuclear Information System (INIS)

Bouvard, G.; Fernandez, Y.; Petit-Taboue, M.C.; Derlon, J.M.; Travere, J.M.; Le Poec, C.

1991-01-01

The quantified measurement of cerebral blood volume is interesting for the brain blood circulation studies. This measurement is often used in positron computed tomography. It's more difficult in single photon emission computed tomography: there are physical problems with the limited resolution of the detector, the Compton effect and the photon attenuation. The objectif of this study is to compare the results between these two techniques. The quantified measurement of brain blood volume is possible with the single photon emission computer tomogragry. However, there is a loss of contrast [fr

NOFBX Single-Stage-to-Orbit Mars Ascent Vehicle Engine, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — We propose the continuation of our research and development of a Nitrous Oxide Fuel Blend (NOFBXTM) Single-Stage-to-Orbit (SSTO) monopropellant propulsion system for...

Advances in single- and multi-stage Stirling-type pulse tube cryocoolers for space applications in NLIP/SITP/CAS

Science.gov (United States)

Dang, Haizheng; Tan, Jun; Zha, Rui; Li, Jiaqi; Zhang, Lei; Zhao, Yibo; Gao, Zhiqian; Bao, Dingli; Li, Ning; Zhang, Tao; Zhao, Yongjiang; Zhao, Bangjian

2017-12-01

This paper presents a review of recent advances in single- and multi-stage Stirling-type pulse tube cryocoolers (SPTCs) for space applications developed at the National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (NLIP/SITP/CAS). A variety of single-stage SPTCs operating at 25-150 K have been developed, including several mid-sized ones operating at 80-110 K. Significant progress has been achieved in coolers operating at 30-40 K which use common stainless steel meshes as regenerator matrices. Another important advance is the micro SPTCs with an overall mass of 300-800 g operating at high frequencies varying from 100 Hz to 400 Hz. The main purpose of developing two-stage SPTCs is to simultaneously acquire cooling capacities at both stages, obviating the need for auxiliary precooling in various applications. The three-stage SPTCs are developed mainly for applications at around 10 K, which are also used for precooling the J-T coolers to achieve further lower temperatures. The four-stage SPTCs are developed to directly achieve the liquid helium temperature for cooling space low-Tc superconducting devices and for the deep space exploration as well. Several typical development programs are described and an overview of the cooler performances is presented.

Clinical Outcomes and Risks of Single-stage Bilateral Unicompartmental Knee Arthroplasty via Oxford Phase III

Directory of Open Access Journals (Sweden)

Tong Ma

2015-01-01

Full Text Available Background: Osteoarthritis often affects the joint bilaterally, and the single-stage (SS unicompartmental knee arthroplasty (UKA is advantageous in terms of a single anesthesia administration, a short hospital stay, lower medical costs, and enhanced patient convenience. However, the complication risk of SS UKA continues to be debated. The aim of this article was to evaluate the clinical effectiveness, complications, and functional recovery of SS and two-stage (TS UKA. Methods: From January 2008 to December 2013, we compared a series of 36 SS UKA with 45 TS UKA for osteoarthritis. The mean age was 65.4 years (range: 55-75 years. The mean body mass index was 25.2 kg/m 2 (range: 22-29 kg/m 2 . The pre- and post-operative Oxford Knee Scores (OKSs, complications, operative times, tourniquet times, the amount of drainage, and hemoglobin (Hb were evaluated. The Chi-square test, Fisher′s exact test, and paired and grouped t-tests were used in this study. Results: The mean follow-up was 50 months. No complications of death, fat embolism, deep vein thrombosis, and prosthetic infection were reported. Patients who underwent SS UKA had a shorter cumulative anesthesia time (113.5 vs. 133.0 min, P 0.05. At the final follow-up, the mean OKS improved from 39.48 ± 5.69 to 18.83 ± 3.82 (P 0.05. Patients who underwent SS UKA had a faster recovery. Conclusions: The single-staged UKA offers the benefits of a single anesthesia administration, reduced total anesthetic time, decreased overall rehabilitation time, and absence of an increase in perioperative mortality or complications compared with the TS bilateral UKA.

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)

One-stage vs two-stage cartilage repair: a current review

Directory of Open Access Journals (Sweden)

Daniel Meyerkort

2010-10-01

Full Text Available Daniel Meyerkort, David Wood, Ming-Hao ZhengCenter for Orthopaedic Research, School of Surgery and Pathology, University of Western Australia, Perth, AustraliaIntroduction: Articular cartilage has a poor capacity for regeneration if damaged. Various methods have been used to restore the articular surface, improve pain, function, and slow progression to osteoarthritis.Method: A PubMed review was performed on 18 March, 2010. Search terms included “autologous chondrocyte implantation (ACI” and “microfracture” or “mosaicplasty”. The aim of this review was to determine if 1-stage or 2-stage procedures for cartilage repair produced different functional outcomes.Results: The main procedures currently used are ACI and microfracture. Both first-generation ACI and microfracture result in clinical and functional improvement with no significant differences. A significant increase in functional outcome has been observed in second-generation procedures such as Hyalograft C, matrix-induced ACI, and ChondroCelect compared with microfracture. ACI results in a higher percentage of patients with clinical improvement than mosaicplasty; however, these results may take longer to achieve.Conclusion: Clinical and functional improvements have been demonstrated with ACI, microfracture, mosaicplasty, and synthetic cartilage constructs. Heterogeneous products and lack of good-quality randomized-control trials make product comparison difficult. Future developments involve scaffolds, gene therapy, growth factors, and stem cells to create a single-stage procedure that results in hyaline articular cartilage.Keywords: autologous chondrocyte implantation, microfracture, cartilage repair

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis

OpenAIRE

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Zhang, Yupeng; Liu, Zheng

2015-01-01

Objective: The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation.Methods: Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reco...

Impact of two-stage turbocharging architectures on pumping losses of automotive engines based on an analytical model

International Nuclear Information System (INIS)

Galindo, J.; Serrano, J.R.; Climent, H.; Varnier, O.

2010-01-01

Present work presents an analytical study of two-stage turbocharging configuration performance. The aim of this work is to understand the influence of different two-stage-architecture parameters to optimize the use of exhaust manifold gases energy and to aid decision making process. An analytical model giving the relationship between global compression ratio and global expansion ratio is developed as a function of basic engine and turbocharging system parameters. Having an analytical solution, the influence of different variables, such as expansion ratio between HP and LP turbine, intercooler efficiency, turbochargers efficiency, cooling fluid temperature and exhaust temperature are studied independently. Engine simulations with proposed analytical model have been performed to analyze the influence of these different parameters on brake thermal efficiency and pumping mean effective pressure. The results obtained show the overall performance of the two-stage system for the whole operative range and characterize the optimum control of the elements for each operative condition. The model was also used to compare single-stage and two-stage architectures performance for the same engine operative conditions. Benefits and limits in terms of breathing capabilities and brake thermal efficiency of each type of system have been presented and analyzed.

Mathematical modeling of a continuous alcoholic fermentation process in a two-stage tower reactor cascade with flocculating yeast recycle.

Science.gov (United States)

de Oliveira, Samuel Conceição; de Castro, Heizir Ferreira; Visconti, Alexandre Eliseu Stourdze; Giudici, Reinaldo

2015-03-01

Experiments of continuous alcoholic fermentation of sugarcane juice with flocculating yeast recycle were conducted in a system of two 0.22-L tower bioreactors in series, operated at a range of dilution rates (D 1 = D 2 = 0.27-0.95 h(-1)), constant recycle ratio (α = F R /F = 4.0) and a sugar concentration in the feed stream (S 0) around 150 g/L. The data obtained in these experimental conditions were used to adjust the parameters of a mathematical model previously developed for the single-stage process. This model considers each of the tower bioreactors as a perfectly mixed continuous reactor and the kinetics of cell growth and product formation takes into account the limitation by substrate and the inhibition by ethanol and biomass, as well as the substrate consumption for cellular maintenance. The model predictions agreed satisfactorily with the measurements taken in both stages of the cascade. The major differences with respect to the kinetic parameters previously estimated for a single-stage system were observed for the maximum specific growth rate, for the inhibition constants of cell growth and for the specific rate of substrate consumption for cell maintenance. Mathematical models were validated and used to simulate alternative operating conditions as well as to analyze the performance of the two-stage process against that of the single-stage process.

High-volume ovarian cancer care: survival impact and disparities in access for advanced-stage disease.

Science.gov (United States)

Bristow, Robert E; Chang, Jenny; Ziogas, Argyrios; Randall, Leslie M; Anton-Culver, Hoda

2014-02-01

To characterize the impact of hospital and physician ovarian cancer case volume on survival for advanced-stage disease and investigate socio-demographic variables associated with access to high-volume providers. Consecutive patients with stage IIIC/IV epithelial ovarian cancer (1/1/96-12/31/06) were identified from the California Cancer Registry. Disease-specific survival analysis was performed using Cox-proportional hazards model. Multivariate logistic regression analyses were used to evaluate for differences in access to high-volume hospitals (HVH) (≥20 cases/year), high-volume physicians (HVP) (≥10 cases/year), and cross-tabulations of high- or low-volume hospital (LVH) and physician (LVP) according to socio-demographic variables. A total of 11,865 patients were identified. The median ovarian cancer-specific survival for all patients was 28.2 months, and on multivariate analysis the HVH/HVP provider combination (HR = 1.00) was associated with superior ovarian cancer-specific survival compared to LVH/LVP (HR = 1.31, 95%CI = 1.16-1.49). Overall, 2119 patients (17.9%) were cared for at HVHs, and 1791 patients (15.1%) were treated by HVPs. Only 4.3% of patients received care from HVH/HVP, while 53.1% of patients were treated by LVH/LVP. Both race and socio-demographic characteristics were independently associated with an increased likelihood of being cared for by the LVH/LVP combination and included: Hispanic race (OR = 1.72, 95%CI = 1.22-2.42), Asian/Pacific Islander race (OR = 1.57, 95%CI = 1.07-2.32), Medicaid insurance (OR = 2.51, 95%CI = 1.46-4.30), and low socioeconomic status (OR = 2.84, 95%CI = 1.90-4.23). Among patients with advanced-stage ovarian cancer, the provider combination of HVH/HVP is an independent predictor of improved disease-specific survival. Access to high-volume ovarian cancer providers is limited, and barriers are more pronounced for patients with low socioeconomic status, Medicaid insurance, and racial minorities. Copyright © 2013

Condensate from a two-stage gasifier

DEFF Research Database (Denmark)

Bentzen, Jens Dall; Henriksen, Ulrik Birk; Hindsgaul, Claus

2000-01-01

Condensate, produced when gas from downdraft biomass gasifier is cooled, contains organic compounds that inhibit nitrifiers. Treatment with activated carbon removes most of the organics and makes the condensate far less inhibitory. The condensate from an optimised two-stage gasifier is so clean...... that the organic compounds and the inhibition effect are very low even before treatment with activated carbon. The moderate inhibition effect relates to a high content of ammonia in the condensate. The nitrifiers become tolerant to the condensate after a few weeks of exposure. The level of organic compounds...... and the level of inhibition are so low that condensate from the optimised two-stage gasifier can be led to the public sewer....

Characteristics and Sampling Efficiencies of Two Impactor Bioaerosol Samplers: MAS-100(Registered) (Microbial Air Monitoring System) and Single-Stage Andersen Viable Microbial Samplers

National Research Council Canada - National Science Library

Hottell, K

2004-01-01

.... A petri dish with agar is used as the impaction surface for these samplers. The MAS-l00 is a single-stage impactor that aspirates air through a 400-hole perforated entry plate onto an agar plate at an airflow rate of 100 L/min...

Evidence of two-stage melting of Wigner solids

Science.gov (United States)

Knighton, Talbot; Wu, Zhe; Huang, Jian; Serafin, Alessandro; Xia, J. S.; Pfeiffer, L. N.; West, K. W.

2018-02-01

Ultralow carrier concentrations of two-dimensional holes down to p =1 ×109cm-2 are realized. Remarkable insulating states are found below a critical density of pc=4 ×109cm-2 or rs≈40 . Sensitive dc V-I measurement as a function of temperature and electric field reveals a two-stage phase transition supporting the melting of a Wigner solid as a two-stage first-order transition.

Practical Considerations Concerning the Interleaved Transition Mode Single-stage Ballast

DEFF Research Database (Denmark)

Teodorescu, Remus; Kjær, Søren Bækhøj; Munk-Nielsen, Stig

2002-01-01

The aim of this paper is to present a novel single-stage interleaved ballast focusing on practical design aspects like: key current expression, overall losses, harmonic analysis of the differential-mode EMI current and preheating ballast function. A new preheating method is also presented. A PSPICE...

A portable high-power diode laser-based single-stage ceramic tile grout sealing system

Science.gov (United States)

Lawrence, J.; Schmidt, M. J. J.; Li, L.; Edwards, R. E.; Gale, A. W.

2002-02-01

By means of a 60 W high-power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/ mm2 and at rates of up to 600 mm/ min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given.

Two-stage liquefaction of a Spanish subbituminous coal

Energy Technology Data Exchange (ETDEWEB)

Martinez, M.T.; Fernandez, I.; Benito, A.M.; Cebolla, V.; Miranda, J.L.; Oelert, H.H. (Instituto de Carboquimica, Zaragoza (Spain))

1993-05-01

A Spanish subbituminous coal has been processed in two-stage liquefaction in a non-integrated process. The first-stage coal liquefaction has been carried out in a continuous pilot plant in Germany at Clausthal Technical University at 400[degree]C, 20 MPa hydrogen pressure and anthracene oil as solvent. The second-stage coal liquefaction has been performed in continuous operation in a hydroprocessing unit at the Instituto de Carboquimica at 450[degree]C and 10 MPa hydrogen pressure, with two commercial catalysts: Harshaw HT-400E (Co-Mo/Al[sub 2]O[sub 3]) and HT-500E (Ni-Mo/Al[sub 2]O[sub 3]). The total conversion for the first-stage coal liquefaction was 75.41 wt% (coal d.a.f.), being 3.79 wt% gases, 2.58 wt% primary condensate and 69.04 wt% heavy liquids. The heteroatoms removal for the second-stage liquefaction was 97-99 wt% of S, 85-87 wt% of N and 93-100 wt% of O. The hydroprocessed liquids have about 70% of compounds with boiling point below 350[degree]C, and meet the sulphur and nitrogen specifications for refinery feedstocks. Liquids from two-stage coal liquefaction have been distilled, and the naphtha, kerosene and diesel fractions obtained have been characterized. 39 refs., 3 figs., 8 tabs.

The effect of seasonal harvesting on a single-species discrete population model with stage structure and birth pulses

International Nuclear Information System (INIS)

Gao Shujing; Chen Lansun

2005-01-01

In this paper, we propose an exploited single-species discrete model with stage structure for the dynamics in a fish population for which births occur in a single pulse once per time period. Using the stroboscopic map, we obtain an exact cycle of the system, and obtain the threshold conditions for its stability. Bifurcation diagrams are constructed with the birth rate as the bifurcation parameter, and these are observed to display complex dynamic behaviors, including chaotic bands with period windows, pitch-fork and tangent bifurcation. This suggests that birth pulse provides a natural period or cyclicity that makes the dynamical behavior more complex. Moreover, we show that the timing of harvesting has a strong impact on the persistence of the fish population, on the volume of mature fish stock and on the maximum annual-sustainable yield. An interesting result is obtained that, after the birth pulse, the earlier culling the mature fish, the larger harvest can tolerate

COMMIX-1A: a three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems. Volume I: users manual

International Nuclear Information System (INIS)

Domanus, H.M.; Schmitt, R.C.; Sha, W.T.; Shah, V.L.

1983-12-01

The COMMIX-1A computer program is an updated and improved version of COMMIX-1 designed to analyze steady-state/transient, single-phase, three-dimensional fluid flow with heat transfer in reactor components and multicomponent systems. A new porous-media formulation via local volume averaging has been derived and employed in the COMMIX code. The concepts of volume porosity, directional surface permeability, distributed resistance, and distributed heat source or sink is used in the new porous-media formulation to model a flow domain with stationary structures. The concept of directional surface permeability is new and greatly facilitates modeling of velocity and temperature fields in anisotropic media. The new porous-media formulation represents the first unified approach to thermal-hydraulic analysis. It is now possible to perform a multidimensional thermal-hydraulic simulation of either a single component, such as a rod bundle, reactor plenum, piping system, heat exchanger, etc., or a multicomponent system that is a combination of these components. The conservation equations of mass, momentum, and energy based on the new porous-media formulation are solved as a boundary-value problem in space and an initial-value problem in time. Two other unique features provided in the COMMIX-1A code are (1) two solution procedures - a semi-implicit procedure modified from ICE and a fully-implicit procedure, named SIMPLEST-ANL, similar to the SIMPLE/SIMPLER algorithms - available a user's option and (2) a geometrical package capable of approximating many geometries. This report (Volume I) describes in detail the basic equations, formulations, solution procedures, flow charts, rebalancing scheme for faster convergence, options available to users, models to describe the auxiliary phenomena, input instructions, and two sample problems. The Volume II assembles and summarizes the results of many simulations that have been performed with COMMIX-1A computer program

The order and volume fill rates in inventory control systems

DEFF Research Database (Denmark)

Thorstenson, Anders; Larsen, Christian

2014-01-01

This paper differentiates between an order (line) fill rate and a volume fill rate and specifies their performance for different inventory control systems. When the focus is on filling complete customer orders rather than total demanded quantity the order fill rate would be the preferred service...... level measure. The main result shows how the order and volume fill rates are related in magnitude. Earlier results derived for a single-item, single-stage, continuous review inventory system with backordering and constant lead times controlled by a base-stock policy are extended in different directions...... extensions consider more general inventory control review policies with backordering, as well as some relations between service measures. A particularly important result in the paper concerns an alternative service measure, the customer order fill rate, and shows how this measure always exceeds the other two...

Evaluation of single right atrial volume and function with magnetic resonance imaging in children with hypoplastic left heart

Energy Technology Data Exchange (ETDEWEB)

Vijarnsorn, Chodchanok [University of Alberta, Faculty of Medicine and Dentistry, Stollery Children' s Hospital, Edmonton, AB (Canada); Mahidol University, Siriraj Hospital, Bangkok (Thailand); Myers, Kimberley; Patton, David J. [Alberta Children' s Hospital, Section of Pediatric Cardiology, Department of Pediatrics, Department of Pediatrics, Calgary, AB (Canada); Noga, Michelle; Crawley, Cinzia; Tham, Edythe [University of Alberta, Faculty of Medicine and Dentistry, Stollery Children' s Hospital, Edmonton, AB (Canada)

2016-06-15

Standardized methods to evaluate atrial properties in single ventricles are lacking. To determine the feasibility of quantifying right atrial volumes and function in hypoplastic left heart using MRI. We studied 15 infants with hypoplastic left heart prior to Glenn surgery (mean age 4.2 months [standard deviation 0.3]) who underwent cardiac MRI with evaluation of atrial volumes and emptying fraction using monoplane two-chamber, monoplane four-chamber, and biplane methods, all of which were compared to the atrial short-axial oblique stack method. We compared atrial end-diastolic volume, end-systolic volume and emptying fraction among these methods. We analyzed reproducibility of the methods using Bland-Altman plots. Both four-chamber and biplane methods showed high correlations for atrial end-diastolic volume (r = 0.7 and r = 0.8, respectively; P < 0.01) and end-systolic volume (r = 0.8 and r = 0.9, respectively; P < 0.01) with small mean differences (-0.2 ± 2.9 standard deviation [SD] ml and -0.8 ± 1.6 ml, respectively, for atrial end-diastolic volume and -0.8 ± 1.5 ml and -0.9 ± 0.9 ml, respectively, for atrial end-systolic volume). The short-axial oblique method was the most reproducible, followed by the four-chamber method. MRI assessment of atrial volume and function is feasible in hypoplastic left heart and might provide further insight into single-ventricle mechanics. (orig.)

One-stage and two-stage penile buccal mucosa urethroplasty

African Journals Online (AJOL)

G. Barbagli

2015-12-02

Dec 2, 2015 ... there also seems to be a trend of decreasing urethritis and an increase of instrumentation and catheter related strictures in these countries as well [4–6]. The repair of penile urethral strictures may require one- or two- stage urethroplasty [7–10]. Certainly, sexual function can be placed at risk by any surgery ...

Two-Stage n-PSK Partitioning Carrier Phase Recovery Scheme for Circular mQAM Coherent Optical Systems

Directory of Open Access Journals (Sweden)

Jaime Rodrigo Navarro

2016-06-01

Full Text Available A novel two-stage n-PSK partitioning carrier phase recovery (CPR scheme for circular multilevel quadrature amplitude modulation (C-mQAM constellations is presented. The first stage of the algorithm provides an initial rough estimation of the received constellation, which is utilized in the second stage for CPR. The performance of the proposed algorithm is studied through extensive simulations at the forward error correction bit error rate targets of 3.8 × 10−3 and 1 × 10−2 and is compared with different CPR algorithms. A significant improvement in the combined linewidth symbol duration product (ΔνTs tolerance is achieved compared to the single-stage n-PSK partitioning scheme. Superior performance in the ΔνTs tolerance compared to the blind phase search algorithm is also reported. The relative improvements with respect to other CPR schemes are also validated experimentally for a 28-Gbaud C-16QAM back-to-back transmission system. The computational complexity of the proposed CPR scheme is studied, and reduction factors of 24.5 | 30.1 and 59.1 | 63.3 are achieved for C-16QAM and C-64QAM, respectively, compared to single-stage BPS in the form of multipliers | adders.

FDG-PET/CT imaging for staging and target volume delineation in conformal radiotherapy of anal carcinoma

International Nuclear Information System (INIS)

Krengli, Marco; Inglese, Eugenio; Milia, Maria E; Turri, Lucia; Mones, Eleonora; Bassi, Maria C; Cannillo, Barbara; Deantonio, Letizia; Sacchetti, Gianmauro; Brambilla, Marco

2010-01-01

FDG-PET/CT imaging has an emerging role in staging and treatment planning of various tumor locations and a number of literature studies show that also the carcinoma of the anal canal may benefit from this diagnostic approach. We analyzed the potential impact of FDG-PET/CT in stage definition and target volume delineation of patients affected by carcinoma of the anal canal and candidates for curative radiotherapy. Twenty seven patients with biopsy proven anal carcinoma were enrolled. Pathology was squamous cell carcinoma in 20 cases, cloacogenic carcinoma in 3, adenocarcinoma in 2, and basal cell carcinoma in 2. Simulation was performed by PET/CT imaging with patient in treatment position. Gross Tumor Volume (GTV) and Clinical Target Volume (CTV) were drawn on CT and on PET/CT fused images. PET-GTV and PET-CTV were respectively compared to CT-GTV and CT-CTV by Wilcoxon rank test for paired data. PET/CT fused images led to change the stage in 5/27 cases (18.5%): 3 cases from N0 to N2 and 2 from M0 to M1 leading to change the treatment intent from curative to palliative in a case. Based on PET/CT imaging, GTV and CTV contours changed in 15/27 (55.6%) and in 10/27 cases (37.0%) respectively. PET-GTV and PET-CTV resulted significantly smaller than CT-GTV (p = 1.2 × 10 -4 ) and CT-CTV (p = 2.9 × 10 -4 ). PET/CT-GTV and PET/CT-CTV, that were used for clinical purposes, were significantly greater than CT-GTV (p = 6 × 10 -5 ) and CT-CTV (p = 6 × 10 -5 ). FDG-PET/CT has a potential relevant impact in staging and target volume delineation of the carcinoma of the anal canal. Clinical stage variation occurred in 18.5% of cases with change of treatment intent in 3.7%. The GTV and the CTV changed in shape and in size based on PET/CT imaging

Two-Stage Variable Sample-Rate Conversion System

Science.gov (United States)

Tkacenko, Andre

2009-01-01

A two-stage variable sample-rate conversion (SRC) system has been pro posed as part of a digital signal-processing system in a digital com munication radio receiver that utilizes a variety of data rates. The proposed system would be used as an interface between (1) an analog- todigital converter used in the front end of the receiver to sample an intermediatefrequency signal at a fixed input rate and (2) digita lly implemented tracking loops in subsequent stages that operate at v arious sample rates that are generally lower than the input sample r ate. This Two-Stage System would be capable of converting from an input sample rate to a desired lower output sample rate that could be var iable and not necessarily a rational fraction of the input rate.

New results for single stage low energy carbon AMS

International Nuclear Information System (INIS)

Klody, G.M.; Schroeder, J.B.; Norton, G.A.; Loger, R.L.; Kitchen, R.L.; Sundquist, M.L.

2005-01-01

A new configuration of the NEC single stage, low energy carbon AMS system (U.S. Patent 6,815,666 B2) has been built and tested. The injector includes two 40-sample ion sources, electrostatic and magnetic analysis, and fast sequential injection. The gas stripper, analyzing magnet, electrostatic analyzer, and detector are on an open air 250 kV deck. Both 12 C and 13 C currents are measured on the deck after the stripper, and an SSB detector is used for 14 C counting. Injected 12 C and mass 13 ( 13 C and 12 CH) currents are also measured. Automated controls follow a user-specified run list for unattended operation. Initial test results show precision for 14 C/ 12 C ratios of better than 5 per mil, and backgrounds for unprocessed graphite of less than 0.005 x modern. We will report final results for precision, background, and throughput and discuss related design features

Updated Drainable Interstitial Liquid Volume Estimates for 119 Single Shell Tanks (SST) Declared Stabilized

International Nuclear Information System (INIS)

FIELD, J.G.

2000-01-01

This document assesses the volume of drainable interstitial liquid (DIL) and pumpable liquid remaining in 119 single-shell tanks (SSTs) that were previously stabilized. Based on the methodology and assumptions presented, the DIL exceeded the stabilization criterion of less than 50,000 gal in two of the 119 SSTs. Tank 241-C-102 had an estimated DIL of 62,000 gal, and the estimated DIL for tank 241-BY-103 was 58,000 gal. In addition, tanks 241-BX-103, 241-T-102, and 241-T-112 appear to exceed the stabilization criterion of 5,000 gal supernatant. An assessment of the source of the supernatant in these tanks is beyond the scope of this document. The actual DIL and pumpable liquid remaining volumes for each tank may vary significantly from estimated volumes as a result of specific tank waste characteristics that are not currently measured or defined. Further refinement to the pumpable liquid and DIL volume estimates may be needed as additional tank waste information is obtained

Anti-kindling induced by two-stage coordinated reset stimulation with weak onset intensity

Directory of Open Access Journals (Sweden)

Magteld eZeitler

2016-05-01

Full Text Available Abnormal neuronal synchrony plays an important role in a number of brain diseases. To specifically counteract abnormal neuronal synchrony by desynchronization, Coordinated Reset (CR stimulation, a spatiotemporally patterned stimulation technique, was designed with computational means. In neuronal networks with spike timing–dependent plasticity CR stimulation causes a decrease of synaptic weights and finally anti-kindling, i.e. unlearning of abnormally strong synaptic connectivity and abnormal neuronal synchrony. Long-lasting desynchronizing aftereffects of CR stimulation have been verified in pre-clinical and clinical proof of concept studies. In general, for different neuromodulation approaches, both invasive and non-invasive, it is desirable to enable effective stimulation at reduced stimulation intensities, thereby avoiding side effects. For the first time, we here present a two-stage CR stimulation protocol, where two qualitatively different types of CR stimulation are delivered one after another, and the first stage comes at a particularly weak stimulation intensity. Numerical simulations show that a two-stage CR stimulation can induce the same degree of anti-kindling as a single-stage CR stimulation with intermediate stimulation intensity. This stimulation approach might be clinically beneficial in patients suffering from brain diseases characterized by abnormal neuronal synchrony where a first treatment stage should be performed at particularly weak stimulation intensities in order to avoid side effects. This might, e.g., be relevant in the context of acoustic CR stimulation in tinnitus patients with hyperacusis or in the case of electrical deep brain CR stimulation with sub-optimally positioned leads or side effects caused by stimulation of the target itself. We discuss how to apply our method in first in man and proof of concept studies.

Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

International Nuclear Information System (INIS)

Combs, S.K.; Milora, S.L.; Foust, C.R.; Gouge, M.J.; Fehling, D.T.; Sparks, D.O.

1988-01-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume (/ 3 for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of ∼3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications. 25 refs., 6 figs., 1 tab

A Two-Stage Queue Model to Optimize Layout of Urban Drainage System considering Extreme Rainstorms

OpenAIRE

He, Xinhua; Hu, Wenfa

2017-01-01

Extreme rainstorm is a main factor to cause urban floods when urban drainage system cannot discharge stormwater successfully. This paper investigates distribution feature of rainstorms and draining process of urban drainage systems and uses a two-stage single-counter queue method M/M/1→M/D/1 to model urban drainage system. The model emphasizes randomness of extreme rainstorms, fuzziness of draining process, and construction and operation cost of drainage system. Its two objectives are total c...

Impact of FDG-PET/CT on Radiotherapy Volume Delineation in Non-Small-Cell Lung Cancer and Correlation of Imaging Stage With Pathologic Findings

International Nuclear Information System (INIS)

Faria, Sergio L.; Menard, Sonia; Devic, Slobodan; Sirois, Christian; Souhami, Luis; Lisbona, Robert; Freeman, Carolyn R.

2008-01-01

Purpose: Fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) is more accurate than CT in determining the extent of non-small-cell lung cancer. We performed a study to evaluate the impact of FDG-PET/CT on the radiotherapy volume delineation compared with CT without using any mathematical algorithm and to correlate the findings with the pathologic examination findings. Methods and Materials: A total of 32 patients with proven non-small-cell lung cancer, pathologic specimens from the mediastinum and lung primary, and pretreatment chest CT and FDG-PET/CT scans were studied. For each patient, two data sets of theoretical gross tumor volumes were contoured. One set was determined using the chest CT only, and the second, done separately, was based on the co-registered FDG-PET/CT data. The disease stage of each patient was determined using the TNM staging system for three data sets: the CT scan only, FDG-PET/CT scan, and pathologic findings. Results: Pathologic examination altered the CT-determined stage in 22 (69%) of 32 patients and the PET-determined stage in 16 (50%) of 32 patients. The most significant alterations were related to the N stage. PET altered the TNM stage in 15 (44%) of 32 patients compared with CT alone, but only 7 of these 15 alterations were confirmed by the pathologic findings. With respect to contouring the tumor volume for radiotherapy, PET altered the contour in 18 (56%) of 32 cases compared with CT alone. Conclusion: The contour of the tumor volume of non-small-cell lung cancer patients with co-registered FDG-PET/CT resulted in >50% alterations compared with CT targeting, findings similar to those of other publications. However, the significance of this change is unknown. Furthermore, pathologic examination showed that PET is not always accurate and histologic examination should be obtained to confirm the findings of PET whenever possible

Simulation, design and proof-of-concept of a two-stage continuous hydrothermal flow synthesis reactor for synthesis of functionalized nano-sized inorganic composite materials

DEFF Research Database (Denmark)

Zielke, Philipp; Xu, Yu; Simonsen, Søren Bredmose

2016-01-01

Computational fluid dynamics simulations were employed to evaluate several mixer geometries for a novel two-stage continuous hydrothermal flow synthesis reactor. The addition of a second stage holds the promise of allowing the synthesis of functionalized nano-materials as for example core-shell...... or decorated particles. Based on the simulation results, a reactor system employing a confined jet mixer in the first and a counter-flow mixer in the second stage was designed and built. The two-stage functionality and synthesis capacity is shown on the example of single- and two-stage syntheses of pure...... and mixed-phase NiO and YSZ particles....

Single column and two-column H-D-T distillation experiments at TSTA

International Nuclear Information System (INIS)

Yamanishi, T.; Yoshida, H.; Hirata, S.; Naito, T.; Naruse, Y.; Sherman, R.H.; Bartlit, J.R.; Anderson, J.L.

1988-01-01

Cryogenic distillation experiments were peformed at TSTA with H-D-T system by using a single column and a two-column cascade. In the single column experiment, fundamental engineering data such as the liquid holdup and the HETP were measured under a variety of operational condtions. The liquid holdup in the packed section was about 10 /approximately/ 15% of its superficial volume. The HETP values were from 4 to 6 cm, and increased slightly with the vapor velocity. The reflux ratio had no effect on the HETP. For the wo-colunn experiemnt, dynamic behavior of the cascade was observed. 8 refs., 7 figs., 2 tabs

Tranexamic acid for control of blood loss in bilateral total knee replacement in a single stage

Directory of Open Access Journals (Sweden)

Mandeep S Dhillon

2011-01-01

Full Text Available Background: Tranexamic acid (TEA reduces blood loss and red cell transfusions in patients undergoing unilateral total knee arthroplasty (TKA. However, there is not much literature regarding the use of TEA in patients undergoing bilateral TKA in a single stage and the protocols for administration of TEA in such patients are ill-defined. Materials and Methods: We carried out a case control study evaluating the effect of TEA on postoperative hemoglobin (Hb, total drain output, and number of blood units transfused in 52 patients undergoing bilateral TKA in a single stage, and compared it with 56 matched controls who did not receive TEA. Two doses of TEA were administered in doses of 10 mg / kg each (slow intravenous (IV infusion, with the first dose given just before tourniquet release of the first knee and the second dose three hours after the first one. Results: A statistically significant reduction in the total drain output and requirement of allogenic blood transfusion in cases who received TEA, as compared to the controls was observed. The postoperative Hb and Hb at the time of discharge were found to be lower in the control group, and this result was found to be statistically significant. Conclusion: TEA administered in patients undergoing single stage bilateral TKA helped reduce total blood loss and decreased allogenic blood transfusion requirements. This might be particularly relevant, where facilities such as autologous reinfusion might not be available.

A method for bubble volume calculating in vertical two-phase flow

International Nuclear Information System (INIS)

Wang, H Y; Dong, F

2009-01-01

The movement of bubble is a basic subject in gas-liquid two-phase flow research. A method for calculating bubble volume which is one of the most important characters in bubble motion research was proposed. A suit of visualized experimental device was designed and set up. Single bubble rising in stagnant liquid in a rectangular tank was studied using the high-speed video system. Bubbles generated by four orifice with different diameter (1mm, 2mm, 3mm, 4mm) were recorded respectively. Sequences of recorded high-speed images were processed by digital image processing method, such as image noise remove, binary image transform, bubble filling, and so on. then, Several parameters could be obtained from the processed image. Bubble area, equivalent diameter, bubble velocity, bubble acceleration are all indispensable in bubble volume calculating. In order to get the force balance equation, forces that work on bubble along vertical direction, including drag force, virtual mass force, buoyancy, gravity and liquid thrust, were analyzed. Finally, the bubble volume formula could be derived from the force balance equation and bubble parameters. Examples were given to shown the computing process and results. Comparison of the bubble volume calculated by geomettic method and the present method have shown the superiority of the proposed method in this paper.

Amplitude damping for single-qubit system with single-qubit mixed-state environment

International Nuclear Information System (INIS)

Jung, Eylee; Hwang, Mi-Ra; Ju, You Hwan; Park, D K; Kim, Hungsoo; Kim, Min-Soo; Son, Jin-Woo

2008-01-01

We study a generalized amplitude damping channel when environment is initially in the single-qubit mixed state. Representing the affine transformation of the generalized amplitude damping by a three-dimensional volume, we plot explicitly the volume occupied by the channels simulatable by a single-qubit mixed-state environment. As expected, this volume is embedded in the total volume by the channels which is simulated by a two-qubit enviroment. The volume ratio is approximately 0.08 which is much smaller than 3/8, the volume ratio for generalized depolarizing channels

A Single-Stage High-Power-Factor Light-Emitting Diode (LED Driver with Coupled Inductors for Streetlight Applications

Directory of Open Access Journals (Sweden)

Chun-An Cheng

2017-02-01

Full Text Available This paper presents and implements a single-stage high-power-factor light-emitting diode (LED driver with coupled inductors, suitable for streetlight applications. The presented LED driver integrates an interleaved buck-boost power factor correction (PFC converter with coupled inductors and a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power conversion circuit. Coupled inductors inside the interleaved buck-boost PFC converter sub-circuit are designed to operate in discontinuous conduction mode (DCM for achieving input-current shaping, and the half-bridge-type series resonant converter cascaded with a full-bridge rectifier is designed for obtaining zero-voltage switching (ZVS on two power switches to reduce their switching losses. Analysis of operational modes and design equations for the presented LED driver are described and included. In addition, the presented driver features a high power factor, low total harmonic distortion (THD of input current, and soft switching. Finally, a prototype driver is developed and implemented to supply a 165-W-rated LED streetlight module with utility-line input voltages ranging from 210 to 230 V. Experimental results demonstrate that high power factor (>0.99, low utility-line current THD (<7%, low-output voltage ripples (<1%, low-output current ripples (<10%, and high circuit efficiency (>90% are obtained in the presented single-stage driver for LED streetlight applications.

Single-stage osseointegrated implants for nasal prosthodontic rehabilitation: A clinical report.

Science.gov (United States)

de Carvalho, Bruna M D F; Freitas-Pontes, Karina M; de Negreiros, Wagner A; Verde, Marcus A R L

2015-08-01

Malignant tumors in the nasal region may be treated by means of invasive surgical procedures, with large facial losses. Nasal prostheses, retained by osseointegrated facial implants, instead of plastic surgery, will, in most patients, offer good biomechanical and cosmetic results. This clinical report describes the prosthetic rehabilitation of a patient with nasal cancer who had the entire nasal vestibule removed in a single-stage surgical procedure in order to shorten the rehabilitation time. The nasal prosthesis was built on a 3-magnet bar and was made of platinum silicone with intrinsic pigmentation, thereby restoring the patient's appearance and self-esteem. The authors concluded that single-stage implants may reduce the rehabilitation time to as little as 1 month, and the correct use of materials and techniques may significantly improve the nasal prosthesis. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

A Dual-Stage Two-Phase Model of Selective Attention

Science.gov (United States)

Hubner, Ronald; Steinhauser, Marco; Lehle, Carola

2010-01-01

The dual-stage two-phase (DSTP) model is introduced as a formal and general model of selective attention that includes both an early and a late stage of stimulus selection. Whereas at the early stage information is selected by perceptual filters whose selectivity is relatively limited, at the late stage stimuli are selected more efficiently on a…

Optimization of Removal Efficiency and Minimum Contact Time for Cadmium and Zinc Removal onto Iron-modified Zeolite in a Two-stage Batch Sorption Reactor

Directory of Open Access Journals (Sweden)

M. Ugrina

2018-01-01

Full Text Available In highly congested industrial sites where significant volumes of effluents have to be treated in the minimum contact time, the application of a multi-stage batch reactor is suggested. To achieve better balance between capacity utilization and cost efficiency in design optimization, a two-stage batch reactor is usually the optimal solution. Thus, in this paper, a two-stage batch sorption design approach was applied to the experimental data of cadmium and zinc uptake onto iron-modified zeolite. The optimization approach involves the application of the Vermeulen’s approximation model and mass balance equation to kinetic data. A design analysis method was developed to optimize the removal efficiency and minimum total contact time by combining the time required in the two-stages, in order to achieve the maximum percentage of cadmium and zinc removal using a fixed mass of zeolite. The benefits and limitations of the two-stage design approach have been investigated and discussed

[Comparison research on two-stage sequencing batch MBR and one-stage MBR].

Science.gov (United States)

Yuan, Xin-Yan; Shen, Heng-Gen; Sun, Lei; Wang, Lin; Li, Shi-Feng

2011-01-01

Aiming at resolving problems in MBR operation, like low nitrogen and phosphorous removal efficiency, severe membrane fouling and etc, comparison research on two-stage sequencing batch MBR (TSBMBR) and one-stage aerobic MBR has been done in this paper. The results indicated that TSBMBR owned advantages of SBR in removing nitrogen and phosphorous, which could make up the deficiency of traditional one-stage aerobic MBR in nitrogen and phosphorous removal. During steady operation period, effluent average NH4(+) -N, TN and TP concentration is 2.83, 12.20, 0.42 mg/L, which could reach domestic scenic environment use. From membrane fouling control point of view, TSBMBR has lower SMP in supernatant, specific trans-membrane flux deduction rate, membrane fouling resistant than one-stage aerobic MBR. The sedimentation and gel layer resistant of TSBMBR was only 6.5% and 33.12% of one-stage aerobic MBR. Besides high efficiency in removing nitrogen and phosphorous, TSBMBR could effectively reduce sedimentation and gel layer pollution on membrane surface. Comparing with one-stage MBR, TSBMBR could operate with higher trans-membrane flux, lower membrane fouling rate and better pollutants removal effects.

Two-stage distraction lengthening of the forearm.

Science.gov (United States)

Taghinia, Amir H; Al-Sheikh, Ayman A; Panossian, Andre E; Upton, Joseph

2013-01-01

Single-stage lengthening of the forearm using callus distraction is well described; however, forearm lengthening using a 2-stage technique of distraction followed by bone grafting has received less attention. A 2-staged technique can be a better alternative in cases where the surgeon desires extensive lengthening. A retrospective review was undertaken of eleven 2-stage forearm lengthening procedures performed by 1 surgeon over a 15-year period. Indications were radial longitudinal deficiency (8 patients), neonatal ischemic contractures (2 patients), and septic growth arrest (1 patient). Average follow-up was 2.8 years. Distraction was performed on patients an average of 82 mm over an average duration of 24 weeks. Average time to union from the time of distractor removal and grafting was 87 days. Average healing index was 32.1 d/cm. Distraction problems were common and related to the length of time that the distractor was in place; they included pain, pin-related infections, and multiple mechanical device difficulties. Three patients had nonunion, and another had delayed union; however, additional procedures resulted in ultimate bony union in all patients. Demineralized bone matrix and autologous corticocancellous bone grafts yielded predictable healing and good functional results in short-distance distractions. For longer distractions, free vascularized fibula transfer produced the best outcomes. Intercalary cortical allografts did not heal well. Patients with neonatal Volkmann contractures had the most difficulty with distraction and healing, ultimately obtaining little to no lengthening and poor functional outcomes.

Energy demand in Portuguese manufacturing: a two-stage model

International Nuclear Information System (INIS)

Borges, A.M.; Pereira, A.M.

1992-01-01

We use a two-stage model of factor demand to estimate the parameters determining energy demand in Portuguese manufacturing. In the first stage, a capital-labor-energy-materials framework is used to analyze the substitutability between energy as a whole and other factors of production. In the second stage, total energy demand is decomposed into oil, coal and electricity demands. The two stages are fully integrated since the energy composite used in the first stage and its price are obtained from the second stage energy sub-model. The estimates obtained indicate that energy demand in manufacturing responds significantly to price changes. In addition, estimation results suggest that there are important substitution possibilities among energy forms and between energy and other factors of production. The role of price changes in energy-demand forecasting, as well as in energy policy in general, is clearly established. (author)

Characterization of cyclomorphic stages in the marine tardigrade Halobiotus crispae

DEFF Research Database (Denmark)

Halberg, Kenneth Agerlin; Mortensen, Hans Ramløv; Westh, Peter

2008-01-01

and pseudosimplex 1 (P1) stage. The active stage tolerates large shifts in external salinity. Total body volume of single specimens (350-500 µm) was estimated from microscopical images following salinity transfers from 20 ppt (control) to 2 ppt, 10 ppt and 40 ppt. Our results show that animals in this stage...... experience large changes in total body volume, yet exhibit a regulatory volume decrease/increase over a 48 h period. Hemolymph osmolality was measured by melting point depression in a nanoliter osmometer. In animals kept at 20 ppt the hemolymph osmotic pressure was 926 ± 29 mOsm/kg (n = 6). This value...... changed to 330 ± 50 mOsm/kg (n = 6), 584 ± 68 mOsm/kg (n = 6) and 1297 ± 32 mOsm/kg (n = 6) during exposure to 2 ppt, 10 ppt and 40 ppt respectively. At any given external salinity the active stage hyper-regulates, indicating the excretion of dilute urine. Animals in the P1 stage are freeze tolerant...

Single-stage micro-scale solvent extraction in parallel microbore tubes using MDIMJ

International Nuclear Information System (INIS)

Darekar, Mayur; Singh, K.K.; Joshi, J.M.; Mukhopadhyay, S.; Shenoy, K.T.

2016-01-01

Single-stage micro-scale solvent extraction of U(VI) from simulated lean streams is explored using micro-scale contactor comprising of a MDIMJ (Monoblock Distributor with Integrated Microfluidic Junction) and PTFE microbore tubes. 30% (v/v) TBP in dodecane has been used as the extracting phase. The objective of the study is to demonstrate numbering up approach for scale-up of micro-scale extraction using indigenously conceptualized and fabricated MDIMJ. First the performance of MIDIMJ for equal flow distribution is tested. Then the effects of inlet flow rate and O/A ratio on stage efficiency and percentage extraction are studied. The experiments show that it is easy to scale-up single-stage micro-scale solvent extraction by using MDIMJ for numbering up approach. Maximum capacity tested is 4.8 LPH. With O/A = 2/1, more than 90% extraction is achieved in a very short contact time of less than 3s. The study thus demonstrates possibility of process intensification and easy scale-up of micro-scale solvent extraction

The influence of magnetic field strength in ionization stage on ion transport between two stages of a double stage Hall thruster

International Nuclear Information System (INIS)

Yu Daren; Song Maojiang; Li Hong; Liu Hui; Han Ke

2012-01-01

It is futile for a double stage Hall thruster to design a special ionization stage if the ionized ions cannot enter the acceleration stage. Based on this viewpoint, the ion transport under different magnetic field strengths in the ionization stage is investigated, and the physical mechanisms affecting the ion transport are analyzed in this paper. With a combined experimental and particle-in-cell simulation study, it is found that the ion transport between two stages is chiefly affected by the potential well, the potential barrier, and the potential drop at the bottom of potential well. With the increase of magnetic field strength in the ionization stage, there is larger plasma density caused by larger potential well. Furthermore, the potential barrier near the intermediate electrode declines first and then rises up while the potential drop at the bottom of potential well rises up first and then declines as the magnetic field strength increases in the ionization stage. Consequently, both the ion current entering the acceleration stage and the total ion current ejected from the thruster rise up first and then decline as the magnetic field strength increases in the ionization stage. Therefore, there is an optimal magnetic field strength in the ionization stage to guide the ion transport between two stages.

Improved Short-Term Load Forecasting Based on Two-Stage Predictions with Artificial Neural Networks in a Microgrid Environment

Directory of Open Access Journals (Sweden)

Jaime Lloret

2013-08-01

Full Text Available Short-Term Load Forecasting plays a significant role in energy generation planning, and is specially gaining momentum in the emerging Smart Grids environment, which usually presents highly disaggregated scenarios where detailed real-time information is available thanks to Communications and Information Technologies, as it happens for example in the case of microgrids. This paper presents a two stage prediction model based on an Artificial Neural Network in order to allow Short-Term Load Forecasting of the following day in microgrid environment, which first estimates peak and valley values of the demand curve of the day to be forecasted. Those, together with other variables, will make the second stage, forecast of the entire demand curve, more precise than a direct, single-stage forecast. The whole architecture of the model will be presented and the results compared with recent work on the same set of data, and on the same location, obtaining a Mean Absolute Percentage Error of 1.62% against the original 2.47% of the single stage model.

A preventive maintenance policy based on dependent two-stage deterioration and external shocks

International Nuclear Information System (INIS)

Yang, Li; Ma, Xiaobing; Peng, Rui; Zhai, Qingqing; Zhao, Yu

2017-01-01

This paper proposes a preventive maintenance policy for a single-unit system whose failure has two competing and dependent causes, i.e., internal deterioration and sudden shocks. The internal failure process is divided into two stages, i.e. normal and defective. Shocks arrive according to a non-homogeneous Poisson process (NHPP), leading to the failure of the system immediately. The occurrence rate of a shock is affected by the state of the system. Both an age-based replacement and finite number of periodic inspections are schemed simultaneously to deal with the competing failures. The objective of this study is to determine the optimal preventive replacement interval, inspection interval and number of inspections such that the expected cost per unit time is minimized. A case study on oil pipeline maintenance is presented to illustrate the maintenance policy. - Highlights: • A maintenance model based on two-stage deterioration and sudden shocks is developed. • The impact of internal system state on external shock process is studied. • A new preventive maintenance strategy combining age-based replacements and periodic inspections is proposed. • Postponed replacement of a defective system is provided by restricting the number of inspections.

Callus Distraction Versus Single-Stage Lengthening With Bone Graft for Treatment of Brachymetatarsia: A Systematic Review.

Science.gov (United States)

Jones, Marc D; Pinegar, David M; Rincker, Sarah A

2015-01-01

Brachymetatarsia deformity is a cosmetically displeasing anomaly that can become physically symptomatic. The surgical techniques most commonly used to repair the anomaly include single-stage lengthening with a bone graft, callus distraction, or a combination of bone grafting and callus distraction. A systematic review of the published data was performed to compare the outcomes of these 3 surgical procedures. A total of 61 studies reporting the use of callus distraction or single-stage lengthening, or both, for the treatment of brachymetatarsia were included in the present review. The incidence of major postoperative complications after callus distraction, single-stage lengthening, and the combination procedure was 49 (12.62%), 13 (3.72%), and 3 (33.33%), respectively. The number of minor complications with callus distraction, single-stage lengthening, and the combination procedure was 152 (39.18%), 55 (15.76%), and 1 (11.11%); the mean percentage of the original length achieved was 37.36%, 25.98% and 36.00%; and the mean length achieved was 17.5, 13.2, and 14.0 mm, respectively. The healing index (mo/cm) and healing time was 2.31 and 16.04 weeks, 1.90 and 9.35 weeks, and 3.93 and 14.62 weeks for callus distraction, single-stage lengthening, and the combination procedure, respectively. Our findings indicate that the callus distraction technique is associated with greater length gained but results in greater complication rates and requires almost twice the time to heal. Single-stage lengthening with a bone graft was associated with fewer complications and faster healing times than callus distraction but with lesser gains in length. From the information reported in the studies we reviewed, the prevalence of bilateral brachymetatarsia was 44.52%, and the female/male ratio was 13.7:1. Both of these findings seem to contradict the usual data given (72% for bilateral brachymetatarsia and a female/male ratio of 25:1). Copyright © 2015 American College of Foot and

Investigation of different ethylenediamine-N,N'-disuccinic acid-enhanced washing configurations for remediation of a Cu-contaminated soil: process kinetics and efficiency comparison between single-stage and multi-stage configurations.

Science.gov (United States)

Ferraro, Alberto; Fabbricino, Massimiliano; van Hullebusch, Eric D; Esposito, Giovanni

2017-09-01

A comparison of Cu extraction yields for three different ethylenediamine-N,N'-disuccinic acid (EDDS)-enhanced washing configurations was performed on a Cu-contaminated soil. Batch experiments were used to simulate a single-stage continuous stirred tank reactor (CSTR) and a multi-stage (side feeding and counter-current) reactor. Single-stage CSTR conditions were simulated for various EDDS:(Cu + Cd + Pb + Co + Ni + Zn) molar ratio (EDDS:M ratio) (from 1 to 30) and liquid to soil (L/S) ratio (from 15 to 45). The highest Cu extraction yield (≃56%) was achieved with EDDS:M = 30. In contrast, a Cu extraction yield decrease was observed with increasing L/S ratio with highest extracted Cu achievement (≃48%) for L/S = 15. Side feeding configuration was tested in four experimental conditions through different fractionation mode of EDDS dose and treatment time at each washing step. Results from the four tests showed all enhanced Cu extraction (maximum values from ≃43 to ≃51%) achieved at lower treatment time and lower EDDS:M molar ratio compared to CSTR configuration with L/S = 25 and EDDS:M = 10. The counter-current washing was carried out through two washing flows achieving a process performance enhancement with 27% increase of extracted Cu compared to single-stage CSTR configuration. Higher Cu extraction percentage (36.8%) was observed in the first washing phase than in the second one (24.7%).

Fill Rates of Single-Stage and Multistage Supply Systems

OpenAIRE

Matthew J. Sobel

2004-01-01

A supply system's fill rate is the fraction of demand that is met from on-hand inventory. This paper presents formulas for the fill rate of periodic review supply systems that use base-stock-level policies. The first part of the paper contains fill-rate formulas for a single-stage system and general distributions of demand. When demand is normally distributed, an exact expression uses only the standard normal distribution and density functions, and a good approximation uses only the standard ...

Evaluation of a modified two-stage inferior alveolar nerve block technique: A preliminary investigation

Directory of Open Access Journals (Sweden)

Ashwin Rao

2017-01-01

Full Text Available Introduction: The two-stage technique of inferior alveolar nerve block (IANB administration does not address the pain associated with “needle insertion” and “local anesthetic solution deposition” in the “first stage” of the injection. This study evaluated a “modified two stage technique” to the reaction of children during “needle insertion” and “local anesthetic solution deposition” during the “first stage” and compared it to the “first phase” of the IANB administered with the standard one-stage technique. Materials and Methods: This was a parallel, single-blinded comparative study. A total of 34 children (between 6 and 10 years of age were randomly divided into two groups to receive an IANB either through the modified two-stage technique (MTST (Group A; 15 children or the standard one-stage technique (SOST (Group B; 19 children. The evaluation was done using the Face Legs Activity Cry Consolability (FLACC; which is an objective scale based on the expressions of the child scale. The obtained data was analyzed using Fishers Exact test with the P value set at <0.05 as level of significance. Results: 73.7% of children in Group B indicated moderate pain during the “first phase” of SOST and no children indicated such in the “first stage” of group A. Group A had 33.3% children who scored “0” indicating relaxed/comfortable children compared to 0% in Group B. In Group A, 66.7% of children scored between 1–3 indicating mild discomfort compared to 26.3% in group B. The difference in the scores between the two groups in each category (relaxed/comfortable, mild discomfort, moderate pain was highly significant (P < 0.001. Conclusion: Reaction of children in Group A during “needle insertion” and “local anesthetic solution deposition” in the “first stage” of MTST was significantly lower than that of Group B during the “first phase” of the SOST.

Two-Stage n-PSK Partitioning Carrier Phase Recovery Scheme for Circular mQAM Coherent Optical Systems

DEFF Research Database (Denmark)

Rodrigo Navarro, Jaime; Kakkar, Aditya; Pang, Xiaodan

2016-01-01

(ΔνTs) tolerance is achieved compared to the single-stage n-PSK partitioning scheme. Superior performance in the ΔνTs tolerance compared to the blind phase search algorithm is also reported. The relative improvements with respect to other CPR schemes are also validated experimentally for a 28-Gbaud C......A novel two-stage n-PSK partitioning carrier phase recovery (CPR) scheme for circular multilevel quadrature amplitude modulation (C-mQAM) constellations is presented. The first stage of the algorithm provides an initial rough estimation of the received constellation, which is utilized in the second...... stage for CPR. The performance of the proposed algorithm is studied through extensive simulations at the forward error correction bit error rate targets of 3.8 × 10−3 and 1 × 10−2 and is compared with different CPR algorithms. A significant improvement in the combined linewidth symbol duration product...

Prognostic value of baseline metabolic tumor volume in early stage Hodgkin's lymphoma in the standard arm of H10 trial

DEFF Research Database (Denmark)

Cottereau, Anne Ségolène; Versari, Annibale; Loft, Annika

2018-01-01

and compared to baseline characteristics, staging classifications and iPET2. A total of 258 patients were eligible, 101 favorable and 157 unfavorable. The median follow-up was 55 months, with 27 PFS and 12 OS events. TMTV was prognosticator of PFS (p...We tested baseline PET/CT as a measure of total tumor burden in order to better identify high risk patients in early-stage Hodgkin's lymphoma (HL). Stage I-II HL patients enrolled in the standard arm (combined modality treatment) of the H10 trial (NCT00433433) with available baseline PET...... and interim PET (iPET2) after two cycles of doxorubicine, bleomycin, vinblastine, dacarbazine were included. Total metabolic tumor volume (TMTV) was measured on baseline PET. IPET2 findings were reported negative (DS1-3) or positive (DS4-5) with the Deauville scale. The prognostic value of TMTV was evaluated...

Final Report on Two-Stage Fast Spectrum Fuel Cycle Options

International Nuclear Information System (INIS)

Yang, Won Sik; Lin, C. S.; Hader, J. S.; Park, T. K.; Deng, P.; Yang, G.; Jung, Y. S.; Kim, T. K.; Stauff, N. E.

2016-01-01

This report presents the performance characteristics of two ''two-stage'' fast spectrum fuel cycle options proposed to enhance uranium resource utilization and to reduce nuclear waste generation. One is a two-stage fast spectrum fuel cycle option of continuous recycle of plutonium (Pu) in a fast reactor (FR) and subsequent burning of minor actinides (MAs) in an accelerator-driven system (ADS). The first stage is a sodium-cooled FR fuel cycle starting with low-enriched uranium (LEU) fuel; at the equilibrium cycle, the FR is operated using the recovered Pu and natural uranium without supporting LEU. Pu and uranium (U) are co-extracted from the discharged fuel and recycled in the first stage, and the recovered MAs are sent to the second stage. The second stage is a sodium-cooled ADS in which MAs are burned in an inert matrix fuel form. The discharged fuel of ADS is reprocessed, and all the recovered heavy metals (HMs) are recycled into the ADS. The other is a two-stage FR/ADS fuel cycle option with MA targets loaded in the FR. The recovered MAs are not directly sent to ADS, but partially incinerated in the FR in order to reduce the amount of MAs to be sent to the ADS. This is a heterogeneous recycling option of transuranic (TRU) elements

Two-stage electrolysis to enrich tritium in environmental water

International Nuclear Information System (INIS)

Shima, Nagayoshi; Muranaka, Takeshi

2007-01-01

We present a two-stage electrolyzing procedure to enrich tritium in environmental waters. Tritium is first enriched rapidly through a commercially-available electrolyser with a large 50A current, and then through a newly-designed electrolyser that avoids the memory effect, with a 6A current. Tritium recovery factor obtained by such a two-stage electrolysis was greater than that obtained when using the commercially-available device solely. Water samples collected in 2006 in lakes and along the Pacific coast of Aomori prefecture, Japan, were electrolyzed using the two-stage method. Tritium concentrations in these samples ranged from 0.2 to 0.9 Bq/L and were half or less, that in samples collected at the same sites in 1992. (author)

Two-stage nonrecursive filter/decimator

International Nuclear Information System (INIS)

Yoder, J.R.; Richard, B.D.

1980-08-01

A two-stage digital filter/decimator has been designed and implemented to reduce the sampling rate associated with the long-term computer storage of certain digital waveforms. This report describes the design selection and implementation process and serves as documentation for the system actually installed. A filter design with finite-impulse response (nonrecursive) was chosen for implementation via direct convolution. A newly-developed system-test statistic validates the system under different computer-operating environments

Stage- vs. Channel-strip Metaphor

DEFF Research Database (Denmark)

Gelineck, Steven; Korsgaard, Dannie Michael; Büchert, Morten

2015-01-01

This study compares the stage metaphor and the channel strip metaphor in terms of performance. Traditionally, music mixing consoles employ a channels strip control metaphor for adjusting parameters such as volume and panning of each track. An alternative control metaphor, the so-called stage meta...... is surprisingly similar and thus we are not able to detect any significant difference in performance between the two interfaces. Qualitative data however, suggests that the stage metaphor is largely favoured for its intuitive interaction - confirming earlier studies....

On A Two-Stage Supply Chain Model In The Manufacturing Industry ...

African Journals Online (AJOL)

We model a two-stage supply chain where the upstream stage (stage 2) always meet demand from the downstream stage (stage 1).Demand is stochastic hence shortages will occasionally occur at stage 2. Stage 2 must fill these shortages by expediting using overtime production and/or backordering. We derive optimal ...

Sensitivity of the amplitude of the single muscle fibre action potential to microscopic volume conduction parameters

NARCIS (Netherlands)

Alberts, B.A.; Rutten, Wim; Wallinga, W.; Boom, H.B.K.

1988-01-01

A microscopic model of volume conduction was applied to examine the sensitivity of the single muscle fibre action potential to variations in parameters of the source and of the volume conductor, such as conduction velocity, intracellular conductivity and intracellular volume fraction. The model

Comparisons of dose-volume histograms for proton-beam versus 3-D conformal X-ray therapy in patients with stage I non-small cell lung cancer

International Nuclear Information System (INIS)

Wang, Changlu; Nakayama, Hidetsugu; Sugahara, Shinji; Sakae, Takeji; Tokuuye, Koichi

2009-01-01

Dose-volume histograms (DVHs) were reviewed to determine if there is an advantage of the two modalities when treating patients with non-small cell lung cancer (NSCLC). 24 stage I NSCLC patients who underwent proton-beam therapy (PBT) from June 2003 to May 2007 were included in this study. Based on the same clinical target volumes (CTVs), treatment planning was made to cover CTV within 90% isodose lines. Each patient was evaluated by two sets of DVHs, one for PBT and the other for three-dimensional conformal X-ray therapy (3D-CRT). For all patients, the 95% isodose line covered 86.4% of the CTV for PBT, and 43.2% for 3D-CRT. PBT was associated with significantly lower mean doses to the ipsilateral lung, total lung, heart, esophagus, and spinal cord than 3D-CRT. PBT offered reduced radiation doses to the lung when evaluated in terms of percentage lung volumes receiving ≥ 5 Gy (V 5 ), ≥ 10 Gy (V 10 ), and ≥ 20 Gy (V 20 ) when compared to 3D-CRT. PBT is advantageous over 3D-CRT in reducing doses to the lung, heart, esophagus, and spinal cord in treating stage I NSCLC. (orig.)

Two-Stage Robust Security-Constrained Unit Commitment with Optimizable Interval of Uncertain Wind Power Output

Directory of Open Access Journals (Sweden)

Dayan Sun

2017-01-01

Full Text Available Because wind power spillage is barely considered, the existing robust unit commitment cannot accurately analyze the impacts of wind power accommodation on on/off schedules and spinning reserve requirements of conventional generators and cannot consider the network security limits. In this regard, a novel double-level robust security-constrained unit commitment formulation with optimizable interval of uncertain wind power output is firstly proposed in this paper to obtain allowable interval solutions for wind power generation and provide the optimal schedules for conventional generators to cope with the uncertainty in wind power generation. The proposed double-level model is difficult to be solved because of the invalid dual transform in solution process caused by the coupling relation between the discrete and continuous variables. Therefore, a two-stage iterative solution method based on Benders Decomposition is also presented. The proposed double-level model is transformed into a single-level and two-stage robust interval unit commitment model by eliminating the coupling relation, and then this two-stage model can be solved by Benders Decomposition iteratively. Simulation studies on a modified IEEE 26-generator reliability test system connected to a wind farm are conducted to verify the effectiveness and advantages of the proposed model and solution method.

The order and volume fill rates in inventory control systems

DEFF Research Database (Denmark)

Thorstenson, Anders; Larsen, Christian

2011-01-01

This paper differentiates between an order (line) fill rate and a volume fill rate and specifies their performance for different inventory control systems. When the focus is on filling complete customer orders rather than total quantities the order fill rate would be the preferred service level...... measure. The main result shows how the order and volume fill rates are related in magnitude. Earlier results derived for a single-item, single-stage, continuous review inventory system with backordering and constant lead times controlled by a base-stock policy are extended in different directions...

A Two-Stage Composition Method for Danger-Aware Services Based on Context Similarity

Science.gov (United States)

Wang, Junbo; Cheng, Zixue; Jing, Lei; Ota, Kaoru; Kansen, Mizuo

Context-aware systems detect user's physical and social contexts based on sensor networks, and provide services that adapt to the user accordingly. Representing, detecting, and managing the contexts are important issues in context-aware systems. Composition of contexts is a useful method for these works, since it can detect a context by automatically composing small pieces of information to discover service. Danger-aware services are a kind of context-aware services which need description of relations between a user and his/her surrounding objects and between users. However when applying the existing composition methods to danger-aware services, they show the following shortcomings that (1) they have not provided an explicit method for representing composition of multi-user' contexts, (2) there is no flexible reasoning mechanism based on similarity of contexts, so that they can just provide services exactly following the predefined context reasoning rules. Therefore, in this paper, we propose a two-stage composition method based on context similarity to solve the above problems. The first stage is composition of the useful information to represent the context for a single user. The second stage is composition of multi-users' contexts to provide services by considering the relation of users. Finally the danger degree of the detected context is computed by using context similarity between the detected context and the predefined context. Context is dynamically represented based on two-stage composition rules and a Situation theory based Ontology, which combines the advantages of Ontology and Situation theory. We implement the system in an indoor ubiquitous environment, and evaluate the system through two experiments with the support of subjects. The experiment results show the method is effective, and the accuracy of danger detection is acceptable to a danger-aware system.

Hugoniot measurements in vanadium using the LNL two-stage light-gas gun

International Nuclear Information System (INIS)

Gathers, G.R.; Mitchell, A.C.; Holmes, N.C.

1983-01-01

Hugoniot measurements on vanadium have been made using the LLNL two-stage light-gas gun. The direct collision method with electrical pins and a tantalum flyer accelerated to 6.28 km/s was used. Alt'shuler, et. al., have reported Hugoniot measurements in vanadium using explosives and the impedance match method. They reported a kink in the U/sub s/ - U/sub p/ relationship at 183 GPa, and attribute it to electronic transitions. The upper portion of their curve is based on a single point at 339 GPa. The present work was performed to further investigate the equation-of-state in the high-pressure range

High peak-power kilohertz laser system employing single-stage multi-pass amplification

Science.gov (United States)

Shan, Bing; Wang, Chun; Chang, Zenghu

2006-05-23

The present invention describes a technique for achieving high peak power output in a laser employing single-stage, multi-pass amplification. High gain is achieved by employing a very small "seed" beam diameter in gain medium, and maintaining the small beam diameter for multiple high-gain pre-amplification passes through a pumped gain medium, then leading the beam out of the amplifier cavity, changing the beam diameter and sending it back to the amplifier cavity for additional, high-power amplification passes through the gain medium. In these power amplification passes, the beam diameter in gain medium is increased and carefully matched to the pump laser's beam diameter for high efficiency extraction of energy from the pumped gain medium. A method of "grooming" the beam by means of a far-field spatial filter in the process of changing the beam size within the single-stage amplifier is also described.

Rapid Two-stage Versus One-stage Surgical Repair of Interrupted Aortic Arch with Ventricular Septal Defect in Neonates

Directory of Open Access Journals (Sweden)

Meng-Lin Lee

2008-11-01

Conclusion: The outcome of rapid two-stage repair is comparable to that of one-stage repair. Rapid two-stage repair has the advantages of significantly shorter cardiopulmonary bypass duration and AXC time, and avoids deep hypothermic circulatory arrest. LVOTO remains an unresolved issue, and postoperative aortic arch restenosis can be dilated effectively by percutaneous balloon angioplasty.

Two-stage catalytic up-grading of vacuum residue of a Wandoan coal liquid. [Vacuum residue of coal liquid

Energy Technology Data Exchange (ETDEWEB)

Mochida, I.; Sakanishi, K.; Korai, Y.; Fujitsu, H.

1986-08-01

A successive two-stage hydrotreatment using a commercial Ni-Mo/Al/sub 2/O/sub 3/ catalyst (HDN-30) was applied to the vacuum residue of a Wandoan coal liquid to achieve high levels of hydrocracking, hydrodenitrogenation and hydrodeoxygenation. Two-stage hydrotreatment in 1-methylnaphthalene containing 20wt% fluoranthene as a solvent at solvent/coal liquid ratio of unity removed 83% (overall) of nitrogen and 90% (overall) of oxygen in the asphaltene (benzene-soluble fraction) at 380/sup 0/C for 3 h and at 420/sup 0/C for 3h under hydrogen pressure of 15 MPa and 14 MPa, respectively, while the single stage treatment at 420/sup 0/C for 3 h removed only 41% and 46%, respectively. The same two-stage treatment allowed the overall denitrogenation of 51% and the overall deoxygenation of 67% from a mixture of asphaltene and preasphaltene (THF-soluble fraction). Addition of the catalyst prior to the second stage reaction increased the removal of nitrogen and oxygen to 75 and 82%, respectively, indicating significant catalyst deactivation by the preasphaltene fraction in the first stage. Increasing the solvent/coal liquid ratio to 2 or addition of tetrahydrofluoranthene as a component of the solvent increased the removal of nitrogen and oxygen to 70 and 80%, respectively. Such two-stage hydrotreatment was also effective in refining the whole residue, allowing denitrogenations and deoxygenations of 68 and 75% respectively using tetrahydrofluoranthene. The coke, unreacted coal and minerals in the residue may not cause acute catalyst deactivation. High dissolving ability of the reaction solvents is very effective to decrease catalyst deactivation by carbon deposition. The successive two-stage hydrotreatment also enhanced hydrocracking of polar and resin fractions in the residue into oils (conversion, 65%). (Abstract Truncated)

Theoretical evaluation of the efficiency of gas single-stage reciprocating compressor medium pressure units

Science.gov (United States)

Busarov, S. S.; Vasil'ev, V. K.; Busarov, I. S.; Titov, D. S.; Panin, Ju. N.

2017-08-01

Developed earlier and tested in such working fluid as air, the technology of calculating the operating processes of slow-speed long-stroke reciprocating stages let the authors to obtain successful results concerning compression of gases to medium pressures in one stage. In this connection, the question of the efficiency of the application of slow-speed long-stroke stages in various fields of technology and the national economy, where the working fluid is other gas or gas mixture, is topical. The article presents the results of the efficiency evaluation of single-stage compressor units on the basis of such stages for cases when ammonia, hydrogen, helium or propane-butane mixture is used as the working fluid.

Teaching basic life support with an automated external defibrillator using the two-stage or the four-stage teaching technique.

Science.gov (United States)

Bjørnshave, Katrine; Krogh, Lise Q; Hansen, Svend B; Nebsbjerg, Mette A; Thim, Troels; Løfgren, Bo

2018-02-01

Laypersons often hesitate to perform basic life support (BLS) and use an automated external defibrillator (AED) because of self-perceived lack of knowledge and skills. Training may reduce the barrier to intervene. Reduced training time and costs may allow training of more laypersons. The aim of this study was to compare BLS/AED skills' acquisition and self-evaluated BLS/AED skills after instructor-led training with a two-stage versus a four-stage teaching technique. Laypersons were randomized to either two-stage or four-stage teaching technique courses. Immediately after training, the participants were tested in a simulated cardiac arrest scenario to assess their BLS/AED skills. Skills were assessed using the European Resuscitation Council BLS/AED assessment form. The primary endpoint was passing the test (17 of 17 skills adequately performed). A prespecified noninferiority margin of 20% was used. The two-stage teaching technique (n=72, pass rate 57%) was noninferior to the four-stage technique (n=70, pass rate 59%), with a difference in pass rates of -2%; 95% confidence interval: -18 to 15%. Neither were there significant differences between the two-stage and four-stage groups in the chest compression rate (114±12 vs. 115±14/min), chest compression depth (47±9 vs. 48±9 mm) and number of sufficient rescue breaths between compression cycles (1.7±0.5 vs. 1.6±0.7). In both groups, all participants believed that their training had improved their skills. Teaching laypersons BLS/AED using the two-stage teaching technique was noninferior to the four-stage teaching technique, although the pass rate was -2% (95% confidence interval: -18 to 15%) lower with the two-stage teaching technique.

Millijoule Pulse Energy Second Harmonic Generation With Single-Stage Photonic Bandgap Rod Fiber Laser

DEFF Research Database (Denmark)

Laurila, Marko; Saby, Julien; Alkeskjold, Thomas Tanggaard

2011-01-01

In this paper, we demonstrate, for the first time, a single-stage Q-switched single-mode (SM) ytterbium-doped rod fiber laser delivering record breaking pulse energies at visible and UV light. We use a photonic bandgap rod fiber with a mode field diameter of 59μm based on a new distributed...

Characteristics of bio-oil from the pyrolysis of palm kernel shell in a newly developed two-stage pyrolyzer

International Nuclear Information System (INIS)

Oh, Seung-Jin; Choi, Gyung-Goo; Kim, Joo-Sik

2016-01-01

Pyrolysis of palm kernel shell was performed using a two-stage pyrolyzer consisting of an auger reactor and a fluidized bed reactor within the auger reactor temperature range of ∼290–380 °C at the fluidized bed reactor temperature of ∼520 °C, and with a variable residence time of the feed material in the auger reactor. The highest bio-oil yield of the two-stage pyrolysis was ∼56 wt%. The bio-oil derived from the auger reactor contained degradation products of the hemicelluloses of PKS, such as acetic acid, and furfural, whereas the fluidized bed reactor produced a bio-oil with high concentrations of acetic acid and phenol. The auger reactor temperature and the residence time of PKS in the auger reactor had an influence on the acetic acid concentration in the bio-oil, while their changes did not induce an observable trend on the phenol concentration in the bio-oil derived from the fluidized bed reactor. The maximum concentrations of acetic acid and phenol in bio-oil were ∼78 and 12 wt% dry basis, respectively. As a result, it was possible for the two-stage pyrolyzer to separately produce two different bio-oils in one operation without any costly fractionation process of bio-oils. - Highlights: • The two-stage pyrolyzer is composed of an auger and a fluidized bed reactor. • The two-stage pyrolyzer produced two different bio-oils in a single operation. • The maximum bio-oil yield of the two-stage pyrolysis was ∼56 wt%. • The maximum concentration of acetic acid in bio-oil was ∼78 wt% dry basis. • The maximum concentration of phenol in bio-oil was ∼12 wt% dry basis.

Final Report on Two-Stage Fast Spectrum Fuel Cycle Options

Energy Technology Data Exchange (ETDEWEB)

Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States); Lin, C. S. [Purdue Univ., West Lafayette, IN (United States); Hader, J. S. [Purdue Univ., West Lafayette, IN (United States); Park, T. K. [Purdue Univ., West Lafayette, IN (United States); Deng, P. [Purdue Univ., West Lafayette, IN (United States); Yang, G. [Purdue Univ., West Lafayette, IN (United States); Jung, Y. S. [Purdue Univ., West Lafayette, IN (United States); Kim, T. K. [Argonne National Lab. (ANL), Argonne, IL (United States); Stauff, N. E. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-01-30

This report presents the performance characteristics of two “two-stage” fast spectrum fuel cycle options proposed to enhance uranium resource utilization and to reduce nuclear waste generation. One is a two-stage fast spectrum fuel cycle option of continuous recycle of plutonium (Pu) in a fast reactor (FR) and subsequent burning of minor actinides (MAs) in an accelerator-driven system (ADS). The first stage is a sodium-cooled FR fuel cycle starting with low-enriched uranium (LEU) fuel; at the equilibrium cycle, the FR is operated using the recovered Pu and natural uranium without supporting LEU. Pu and uranium (U) are co-extracted from the discharged fuel and recycled in the first stage, and the recovered MAs are sent to the second stage. The second stage is a sodium-cooled ADS in which MAs are burned in an inert matrix fuel form. The discharged fuel of ADS is reprocessed, and all the recovered heavy metals (HMs) are recycled into the ADS. The other is a two-stage FR/ADS fuel cycle option with MA targets loaded in the FR. The recovered MAs are not directly sent to ADS, but partially incinerated in the FR in order to reduce the amount of MAs to be sent to the ADS. This is a heterogeneous recycling option of transuranic (TRU) elements

Runway Operations Planning: A Two-Stage Heuristic Algorithm

Science.gov (United States)

Anagnostakis, Ioannis; Clarke, John-Paul

2003-01-01

The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, can also be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. This paper introduces a two stage heuristic algorithm for solving the Runway Operations Planning (ROP) problem. In the first stage, sequences of departure class slots and runway crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the departure class slots are populated with specific flights from the pool of available aircraft, by solving an integer program with a Branch & Bound algorithm implementation. Preliminary results from this implementation of the two-stage algorithm on real-world traffic data are presented.

A preventive maintenance model with a two-level inspection policy based on a three-stage failure process

International Nuclear Information System (INIS)

Wang, Wenbin; Zhao, Fei; Peng, Rui

2014-01-01

Inspection is always an important preventive maintenance (PM) activity and can have different depths and cover all or part of plant systems. This paper introduces a two-level inspection policy model for a single component plant system based on a three-stage failure process. Such a failure process divides the system′s life into three stages: good, minor defective and severe defective stages. The first level of inspection, the minor inspection, can only identify the minor defective stage with a certain probability, but can always reveal the severe defective stage. The major inspection can however identify both defective stages perfectly. Once the system is found to be in the minor defective stage, a shortened inspection interval is adopted. If however the system is found to be in the severe defective stage, we may delay the maintenance action if the time to the next planned PM window is less than a threshold level, but otherwise, replace immediately. This corresponds to the well adopted maintenance policy in practice such as periodic inspections with planned PMs. A numerical example is presented to demonstrate the proposed model by comparing with other models. - Highlights: • The system′s deterioration goes through a three-stage process, namely, normal, minor defective and severe defective. • Two levels of inspections are proposed, e.g., minor and major inspections. • Once the minor defective stage is found, instead of taking a maintenance action, a shortened inspection interval is recommended. • When the severe defective stage is found, we delay the maintenance according to the threshold to the next PM. • The decision variables are the inspection intervals and the threshold to PM

Two-stage residual inclusion estimation: addressing endogeneity in health econometric modeling.

Science.gov (United States)

Terza, Joseph V; Basu, Anirban; Rathouz, Paul J

2008-05-01

The paper focuses on two estimation methods that have been widely used to address endogeneity in empirical research in health economics and health services research-two-stage predictor substitution (2SPS) and two-stage residual inclusion (2SRI). 2SPS is the rote extension (to nonlinear models) of the popular linear two-stage least squares estimator. The 2SRI estimator is similar except that in the second-stage regression, the endogenous variables are not replaced by first-stage predictors. Instead, first-stage residuals are included as additional regressors. In a generic parametric framework, we show that 2SRI is consistent and 2SPS is not. Results from a simulation study and an illustrative example also recommend against 2SPS and favor 2SRI. Our findings are important given that there are many prominent examples of the application of inconsistent 2SPS in the recent literature. This study can be used as a guide by future researchers in health economics who are confronted with endogeneity in their empirical work.

Design and construction of a single unit multi-function optical encoder for a six-degree-of-freedom motion error measurement in an ultraprecision linear stage

International Nuclear Information System (INIS)

Lee, ChaBum; Kim, Gyu Ha; Lee, Sun-Kyu

2011-01-01

This paper presents the method of a six-degree-of-freedom (DOF) posture measurement in a linear stage by employing a single unit of an optical encoder. The proposed optical encoder was constructed to simultaneously measure the posture along the traveling axis; angular errors, pitch, yaw and roll; and translational errors, ΔX, ΔY and ΔZ. It consists of a diffractive optical element, a corner cube, four separate two-dimensional position-sensitive detectors, four photodiodes and auxiliary optics components. The circularly polarizing interferometric technique was integrated to measure the displacement of the stage along the traveling axis in a robust manner and the resolution was estimated to be less than 0.4 nm. Two types of stages were employed for the measurement implementation, the piezoelectric transducer-driven and the ballscrew-driven, and they were feedback-controlled for the traveling axis, respectively. With a single travel of the stage, it provided a six-DOF motion error with a high resolution, less than 0.03 arcsec, 20 nm and 0.4 nm for angular errors, ΔY and ΔZ, and ΔX, respectively, at the same time. As a result, it was seen that motion errors of the stage have relevance to the driving mechanism and the whole construction of the stage

Maximally efficient two-stage screening: Determining intellectual disability in Taiwanese military conscripts.

Science.gov (United States)

Chien, Chia-Chang; Huang, Shu-Fen; Lung, For-Wey

2009-01-27

The purpose of this study was to apply a two-stage screening method for the large-scale intelligence screening of military conscripts. We collected 99 conscripted soldiers whose educational levels were senior high school level or lower to be the participants. Every participant was required to take the Wisconsin Card Sorting Test (WCST) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) assessments. Logistic regression analysis showed the conceptual level responses (CLR) index of the WCST was the most significant index for determining intellectual disability (ID; FIQ ≤ 84). We used the receiver operating characteristic curve to determine the optimum cut-off point of CLR. The optimum one cut-off point of CLR was 66; the two cut-off points were 49 and 66. Comparing the two-stage window screening with the two-stage positive screening, the area under the curve and the positive predictive value increased. Moreover, the cost of the two-stage window screening decreased by 59%. The two-stage window screening is more accurate and economical than the two-stage positive screening. Our results provide an example for the use of two-stage screening and the possibility of the WCST to replace WAIS-R in large-scale screenings for ID in the future.

Two-stage single-phase grid-connected photovoltaic system with reduced complexity

Science.gov (United States)

da Silva, Cintia S.; Motta, Filipe R.; Tofoli, Fernando L.

2011-06-01

This article presents a grid-connected photovoltaic (PV) system using the classical DC-DC buck converter, which is responsible for stepping down the resulting voltage from several series-connected panels. Besides, the structure provides high power factor operation by injecting a quasi-sinusoidal current into the grid, with near no displacement in relation to the line voltage at the point of common coupling among the PV system and the loads. A CSI employing thyristors is cascaded with the DC-DC stage so that AC voltage results. The inverter output voltage level is adjusted by using a low-frequency transformer, which also provides galvanic isolation. The proposed system is described as mathematical approach and design guidelines are presented, providing an overview of the topology. An experimental prototype is also implemented, and relevant results to validate the proposal are discussed.

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis.

Science.gov (United States)

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Liu, Zheng; Zhang, Yupeng

2015-01-01

The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. The mean follow-up was 36.9 months (range: 24-62 months). The kyphotic angle ranged from 15.2-35.1° preoperatively, with an average measurement of 27.8°. The American Spinal Injury Association (ASIA) score system was used to evaluate the neurological deficits and erythrocyte sedimentation rate (ESR) used to judge the activity of TB. Spinal TB was completely cured in all 17 patients. There was no recurrent TB infection. The postoperative kyphotic angle was 6.6-10.2°, 8.1° in average, and there was no significant loss of the correction at final follow-up. Solid fusion was achieved in all cases. Neurological condition in all patients was improved after surgery. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation can be a feasible and effective method the in treatment of single-segment lumbar spinal TB.

Single-staged resections and 3D reconstructions of the nasion, glabella, medial orbital wall, and frontal sinus and bone: Long-term outcome and review of the literature.

Science.gov (United States)

Ciporen, Jeremy; Lucke-Wold, Brandon P; Mendez, Gustavo; Chen, Anton; Banerjee, Amit; Akins, Paul T; Balough, Ben J

2016-01-01

Aesthetic facial appearance following neurosurgical ablation of frontal fossa tumors is a primary concern for patients and neurosurgeons alike. Craniofacial reconstruction procedures have drastically evolved since the development of three-dimensional computed tomography imaging and computer-assisted programming. Traditionally, two-stage approaches for resection and reconstruction were used; however, these two-stage approaches have many complications including cerebrospinal fluid leaks, necrosis, and pneumocephalus. We present two successful cases of single-stage osteoma resection and craniofacial reconstruction in a 26-year-old female and 65-year-old male. The biopolymer implants were preselected and contoured based on imaging prior to surgery. The ideal selection of appropriate flaps for reconstruction was imperative. The flaps were well vascularized and included a pedicle for easy translocation. Using a titanium mesh biopolymer implant for reconstruction in conjunction with a forehead flap proved advantageous, and the benefits of single-stage approaches were apparent. The patients recovered quickly after the surgery with complete resection of the osteoma and good aesthetic appearance. The flap adhered to the biopolymer implant, and the cosmetic appearance years after surgery remained decent. The gap between the bone and implant was less than 2 mm. The patients are highly satisfied with the symmetrical appearance of the reconstruction. Advances in technology are allowing neurosurgeons unprecedented opportunities to design complex yet feasible single-stage craniofacial reconstructions that improve a patient's quality of life by enhancing facial contours, aesthetics, and symmetry.

The Two-Word Stage: Motivated by Linguistic or Cognitive Constraints?

Science.gov (United States)

Berk, Stephanie; Lillo-Martin, Diane

2012-01-01

Child development researchers often discuss a "two-word" stage during language acquisition. However, there is still debate over whether the existence of this stage reflects primarily cognitive or linguistic constraints. Analyses of longitudinal data from two Deaf children, Mei and Cal, not exposed to an accessible first language (American Sign…

Metoidioplasty as a single stage sex reassignment surgery in female transsexuals: Belgrade experience.

Science.gov (United States)

Djordjevic, Miroslav L; Stanojevic, Dusan; Bizic, Marta; Kojovic, Vladimir; Majstorovic, Marko; Vujovic, Svetlana; Milosevic, Alexandar; Korac, Gradimir; Perovic, Sava V

2009-05-01

Metoidioplasty represents one of the variants of phalloplasty in female transsexuals. Its main characteristic is that it is a one-stage procedure. It involves lengthening and straightening of hypertrophied clitoris to create a neophallus, urethral lengthening to enable voiding while standing, and scrotal reconstruction with insertion of testicle prostheses. Our aim is to describe our technique and highlight its advantages. Between September 2002 and April 2007, 82 female transsexuals, aged 18-54 years (mean age 31) underwent one-stage metoidioplasty. Clitoris is lengthened and straightened by division of clitoral ligaments and short urethral plate. Urethroplasty is done with combined buccal mucosa graft and genital skin flaps. Scrotum is created from labia majora in which two testicle prostheses are inserted. Simultaneously, female genitalia are removed. Patients' personal satisfaction about sensitivity and length of neophallus, possibility to void in standing position, real length of reconstructed urethra as well as complication rate comparing to other published data. The median follow-up was 32 months (range 14-69). The mean neophallic length was 5.7 cm (range 4-10). Voiding in standing position was reported in all patients, while dribbling and spraying were noticed in 23 cases and solved spontaneously. There were two urethral strictures and seven fistulas that required secondary minor revision. All patients reported preserved sensation and normal postoperative erection. Testicle prostheses rejection was not observed in any of the patients. Metoidioplasty is a single-stage and time-saving procedure. It could be an alternative to total phalloplasty in female transsexuals who do not wish to have sexual intercourse. Also, it represents a first step in cases where additional augmentation phalloplasty is required.

PET/CT and contrast enhanced CT in single vs. two separate sessions: a cost analysis study.

Science.gov (United States)

Picchio, M; Mansueto, M; Crivellaro, C; Guerra, L; Marcelli, S; Arosio, M; Sironi, S; Gianolli, L; Grimaldi, A; Messa, C

2012-06-01

Aim of the study was to quantify the economic impact of PET/CT and contrast enhanced (c.e.) CT performed in a single session examination vs. stand-alone modalities in oncological patients. One-hundred-forty-five cancer patients referred to both PET/CT and c.e. CT, to either stage (N.=46) or re-stage (N.=99) the disease, were included. Seventy-two/145 performed both studies in a single session (innovative method) and 73/145 in two different sessions (traditional method). The cost-minimization analysis was performed by evaluating: 1) institutional costs, data obtained by hospital accountability (staff, medical materials, equipment maintenance and depreciation, departments utilities); 2) patients costs, data obtained by a specific survey provided to patients (travel, food, accommodation costs, productivity loss). Economic data analysis showed that the costs for innovative method was lower than those of traditional method, both for Institution (106 € less per test) and for patient (21 € less per patient). The loss of productivity for patient and caregivers resulted lower for the innovative method than the traditional method (3 work-hour less per person). PET/CT and c.e. CT performed in a single session is more cost-effective than stand-alone modalities, by reducing both Institutional and patients costs. These advantages are mainly due to lower Institutional cost (single procedure) and to lower cost related to travel and housing.

Two-stage double-effect ammonia/lithium nitrate absorption cycle

International Nuclear Information System (INIS)

Ventas, R.; Lecuona, A.; Vereda, C.; Legrand, M.

2016-01-01

Highlights: • A two stage double effect cycle with NH3-LiNO3 is proposed. • The cycle operates at lower pressures than conventional. • Adiabatic absorber offers better performance than the diabatic version. • Evaporator external inlet temperatures higher than −10 °C avoids crystallization. • Maximum COP is 1.25 for driving water inlet temperature of 100 C. - Abstract: The two-stage configuration of a double-effect absorption cycle using ammonia/lithium nitrate as working fluid is studied by means of a thermodynamic model. The maximum pressure of this cycle configuration is the same as the single-effect cycle, up to 15.8 bars, being an advantage over the double-effect conventional configuration with three pressure levels that exhibits much higher maximum pressure. The performance of the cycle and the limitation imposed by crystallization of the working fluid is determined for both adiabatic and diabatic absorber cycles. Both cycles offer similar COP; however the adiabatic variant shows a larger margin against crystallization. This cycle can produce cold for external inlet evaporator temperatures down to −10 °C, but for this limit the crystallization could happen at high inlet generator temperatures. The maximum COP can be 1.25 for an external inlet generator temperature of 100 °C. This cycle shows a better COP than a typical double effect cycle with in-parallel configuration for the range of the moderate temperatures under study and using the same working fluid. Comparisons with double effect cycles using H_2O/LiBr and NH_3/H_2O as working fluids are also offered, highlighting the present configurations advantages regarding COP, evaporation and condensation temperatures as well as crystallization.

Two-Stage Regularized Linear Discriminant Analysis for 2-D Data.

Science.gov (United States)

Zhao, Jianhua; Shi, Lei; Zhu, Ji

2015-08-01

Fisher linear discriminant analysis (LDA) involves within-class and between-class covariance matrices. For 2-D data such as images, regularized LDA (RLDA) can improve LDA due to the regularized eigenvalues of the estimated within-class matrix. However, it fails to consider the eigenvectors and the estimated between-class matrix. To improve these two matrices simultaneously, we propose in this paper a new two-stage method for 2-D data, namely a bidirectional LDA (BLDA) in the first stage and the RLDA in the second stage, where both BLDA and RLDA are based on the Fisher criterion that tackles correlation. BLDA performs the LDA under special separable covariance constraints that incorporate the row and column correlations inherent in 2-D data. The main novelty is that we propose a simple but effective statistical test to determine the subspace dimensionality in the first stage. As a result, the first stage reduces the dimensionality substantially while keeping the significant discriminant information in the data. This enables the second stage to perform RLDA in a much lower dimensional subspace, and thus improves the two estimated matrices simultaneously. Experiments on a number of 2-D synthetic and real-world data sets show that BLDA+RLDA outperforms several closely related competitors.

A two-stage ethanol-based biodiesel production in a packed bed reactor

DEFF Research Database (Denmark)

Xu, Yuan; Nordblad, Mathias; Woodley, John

2012-01-01

were conducted in a simulated series of reactors by repeatedly passing the reaction mixture through a single reactor, with separation of the by-product glycerol and water between passes in the first and second stages, respectively. The second stage brought the major components of biodiesel to ‘in......-spec’ levels according to the European biodiesel specifications for methanol-based biodiesel. The highest overall productivity achieved in the first stage was 2.52 kg FAEE(kg catalyst)−1 h−1 at a superficial velocity of 7.6 cm min−1, close to the efficiency of a stirred tank reactor under similar conditions...

Single-stage intraoperative transhepatic biliary stenting in patients with unresectable hepatobiliary pancreatic tumors.

Science.gov (United States)

Iwasaki, Yoshimi; Kubota, Keiichi; Kita, Junji; Katoh, Masato; Shimoda, Mitsugi; Sawada, Tokihiko; Iso, Yukihiro

2013-02-01

The current study was conducted to evaluate the safety and utility of intraoperative transhepatic biliary stenting (ITBS) in patients with unresectable malignant biliary obstruction (UMBO) diagnosed intraoperatively. In this study, 50 patients who underwent ITBS for UMBO between April 2001 and May 2009 were retrospectively reviewed. For 26 patients who underwent preoperative percutaneous transhepatic biliary drainage (PTBD), the expandable metallic stent (EMS) was inserted intraoperatively by the PTBD route in a single stage. For 24 patients, the intrahepatic bile ducts were intentionally dilated by injection of saline via the endoscopic nasobiliary drainage or the percutaneous transhepatic gallbladder drainage route, and the puncture was performed under intraoperative ultrasound guidance followed by guidewire and catheter insertion. Thereafter, the EMS was placed in the same manner. The initial postoperative complications and long-term results of ITBS were evaluated. In all cases, ITBS was technically successful. Stenting alone was performed in 22 patients and stenting combined with other procedures in 28 patients. Hospital mortality occurred for three patients (6 %), and complication-related mortality occurred in two cases (4 %). There were nine cases (18 %) of postoperative complications. The median survival time was 179 days, and the EMS patency time was 137 days. During the follow-up period, EMS occlusion occurred in 23 cases (46 %). Best supportive care was a significant independent risk factor for early mortality within 100 days after ITBS (p = 0.020, odds ratio, 9.398). Single-stage ITBS is feasible for palliation of UMBO and seems to have a low complication rate.

New current control based MPPT technique for single stage grid connected PV systems

International Nuclear Information System (INIS)

Jain, Sachin; Agarwal, Vivek

2007-01-01

This paper presents a new maximum power point tracking algorithm based on current control for a single stage grid connected photovoltaic system. The main advantage of this algorithm comes from its ability to predict the approximate amplitude of the reference current waveform or power that can be derived from the PV array with the help of an intermediate variable β. A variable step size for the change in reference amplitude during initial tracking helps in fast tracking. It is observed that if the reference current amplitude is greater than the array capacity, the system gets unstable (i.e. moves into the positive slope region of the p-v characteristics of the array). The proposed algorithm prevents the PV system from entering the positive slope region of the p-v characteristics. It is also capable of restoring stability if the system goes unstable due to a sudden environmental change. The proposed algorithm has been tested on a new single stage grid connected PV configuration recently developed by the authors to feed sinusoidal current into the grid. The system is operated in a continuous conduction mode to realize advantages such as low device current stress, high efficiency and low EMI. A fast MPPT tracker with single stage inverter topology operating in CCM makes the overall system highly efficient. Specific cases of the system, operating in just discontinuous current mode and discontinuous current mode and their relative merits and demerits are also discussed

Measurement of average density and relative volumes in a dispersed two-phase fluid

Science.gov (United States)

Sreepada, Sastry R.; Rippel, Robert R.

1992-01-01

An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.

Large Conization and Laparoendoscopic Single-Port Pelvic Lymphadenectomy in Early-Stage Cervical Cancer for Fertility Preservation

Directory of Open Access Journals (Sweden)

Polat Dursun

2013-01-01

Full Text Available Fertility preservation in early-stage cervical cancer is a hot topic in gynecologic oncology. Although radical vaginal trachelectomy (RVT is suggested as a fertility preserving approach, there are some serious concerns like cervical stenosis, second trimester loss, preterm delivery in survivors, and lack of residual tumor in the majority of the surgical specimens. Therefore, less radical surgical operations have been proposed in early-stage cervical carcinomas. On the other hand, single-incision laparoscopic surgery (SILS is an evolving endoscopic approach for minimal access surgery. In this report, we present a case with early-stage cervical cancer who wishes to preserve fertility. We successfully performed single-port pelvic lymphadenectomy and large conization to preserve fertility potential of the patient. We think that combination of less radical approach like conization and single-port pelvic lymphadenectomy might be less minimally invasive and is still an effective surgical approach in well-selected cases with cervical carcinomas. Incorporation of single-port laparoscopy into the minimally invasive fertility sparing management of the cervical cancer will improve patients outcome with less complications and better cosmesis. Further studies are needed to reach a clear conclusion.

A New Concept of Two-Stage Multi-Element Resonant-/Cyclo-Converter for Two-Phase IM/SM Motor

Directory of Open Access Journals (Sweden)

Mahmud Ali Rzig Abdalmula

2013-01-01

Full Text Available The paper deals with a new concept of power electronic two-phase system with two-stage DC/AC/AC converter and two-phase IM/PMSM motor. The proposed system consisting of two-stage converter comprises: input resonant boost converter with AC output, two-phase half-bridge cyclo-converter commutated by HF AC input voltage, and induction or synchronous motor. Such a system with AC interlink, as a whole unit, has better properties as a 3-phase reference VSI inverter: higher efficiency due to soft switching of both converter stages, higher switching frequency, smaller dimensions and weight with lesser number of power semiconductor switches and better price. In comparison with currently used conventional system configurations the proposed system features a good efficiency of electronic converters and also has a good torque overloading of two-phase AC induction or synchronous motors. Design of two-stage multi-element resonant converter and results of simulation experiments are presented in the paper.

Two-Stage Fuzzy Portfolio Selection Problem with Transaction Costs

OpenAIRE

Chen, Yanju; Wang, Ye

2015-01-01

This paper studies a two-period portfolio selection problem. The problem is formulated as a two-stage fuzzy portfolio selection model with transaction costs, in which the future returns of risky security are characterized by possibility distributions. The objective of the proposed model is to achieve the maximum utility in terms of the expected value and variance of the final wealth. Given the first-stage decision vector and a realization of fuzzy return, the optimal value expression of the s...

Adolescence in New Zealand. Volume Two: Wider Perspectives.

Science.gov (United States)

Stewart, Robert A. C., Ed.

This is the second of a two-volume collection of research-based readings dealing with the New Zealand adolescent. This volume considers the areas of drugs and delinquency, as well as the world of work and Maori-pakeha differences. The following topics are included: marihuana use; vocational aspiration; alcohol and tobacco use; Maori-pakeha…

Continuous production of biohythane from hydrothermal liquefied cornstalk biomass via two-stage high-rate anaerobic reactors.

Science.gov (United States)

Si, Bu-Chun; Li, Jia-Ming; Zhu, Zhang-Bing; Zhang, Yuan-Hui; Lu, Jian-Wen; Shen, Rui-Xia; Zhang, Chong; Xing, Xin-Hui; Liu, Zhidan

2016-01-01

Biohythane production via two-stage fermentation is a promising direction for sustainable energy recovery from lignocellulosic biomass. However, the utilization of lignocellulosic biomass suffers from specific natural recalcitrance. Hydrothermal liquefaction (HTL) is an emerging technology for the liquefaction of biomass, but there are still several challenges for the coupling of HTL and two-stage fermentation. One particular challenge is the limited efficiency of fermentation reactors at a high solid content of the treated feedstock. Another is the conversion of potential inhibitors during fermentation. Here, we report a novel strategy for the continuous production of biohythane from cornstalk through the integration of HTL and two-stage fermentation. Cornstalk was converted to solid and liquid via HTL, and the resulting liquid could be subsequently fed into the two-stage fermentation systems. The systems consisted of two typical high-rate reactors: an upflow anaerobic sludge blanket (UASB) and a packed bed reactor (PBR). The liquid could be efficiently converted into biohythane via the UASB and PBR with a high density of microbes at a high organic loading rate. Biohydrogen production decreased from 2.34 L/L/day in UASB (1.01 L/L/day in PBR) to 0 L/L/day as the organic loading rate (OLR) of the HTL liquid products increased to 16 g/L/day. The methane production rate achieved a value of 2.53 (UASB) and 2.54 L/L/day (PBR), respectively. The energy and carbon recovery of the integrated HTL and biohythane fermentation system reached up to 79.0 and 67.7%, respectively. The fermentation inhibitors, i.e., 5-hydroxymethyl furfural (41.4-41.9% of the initial quantity detected) and furfural (74.7-85.0% of the initial quantity detected), were degraded during hydrogen fermentation. Compared with single-stage fermentation, the methane process during two-stage fermentation had a more efficient methane production rate, acetogenesis, and COD removal. The microbial distribution

On the robustness of two-stage estimators

KAUST Repository

Zhelonkin, Mikhail; Genton, Marc G.; Ronchetti, Elvezio

2012-01-01

The aim of this note is to provide a general framework for the analysis of the robustness properties of a broad class of two-stage models. We derive the influence function, the change-of-variance function, and the asymptotic variance of a general

Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

Science.gov (United States)

Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

2016-08-01

This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

Bioremediation of storage tank bottom sludge by using a two-stage composting system: Effect of mixing ratio and nutrients addition.

Science.gov (United States)

Koolivand, Ali; Rajaei, Mohammad Sadegh; Ghanadzadeh, Mohammad Javad; Saeedi, Reza; Abtahi, Hamid; Godini, Kazem

2017-07-01

The effect of mixing ratio and nutrients addition on the efficiency of a two-stage composting system in removal of total petroleum hydrocarbons (TPH) from storage tank bottom sludge (STBS) was investigated. The system consisted of ten windrow piles as primary composting (PC) followed by four in-vessel reactors as secondary composting (SC). Various initial C/N/P and mixing ratios of STBS to immature compost (IC) were examined in the PC and SC for 12 and 6weeks, respectively. The removal rates of TPH in the two-stage system (93.72-95.24%) were higher than those in the single-stage one. Depending on the experiments, TPH biodegradation fitted to the first- and second-order kinetics with the rate constants of 0.051-0.334d -1 and 0.002-0.165gkg -1 d -1 , respectively. The bacteria identified were Pseudomonas sp., Bacillus sp., Klebsiella sp., Staphylococcus sp., and Proteus sp. The study verified that a two-stage composting system is effective in treating the STBS. Copyright © 2017 Elsevier Ltd. All rights reserved.

EVALUATION OF A TWO-STAGE PASSIVE TREATMENT APPROACH FOR MINING INFLUENCE WATERS

Science.gov (United States)

A two-stage passive treatment approach was assessed at bench-scale using two Colorado Mining Influenced Waters (MIWs). The first-stage was a limestone drain with the purpose of removing iron and aluminum and mitigating the potential effects of mineral acidity. The second stage w...

Two-stage supercharging of a passenger car diesel engine; Zweistufige Aufladung eines Pkw-Dieselmotors

Energy Technology Data Exchange (ETDEWEB)

Wittmer, A.; Albrecht, P.; Becker, B.; Vogt, G.; Fischer, R. [Erphi Elektronik GmbH, Holzkirchen (Germany)

2004-07-01

Two-stage supercharging of internal combustion engines with specific capacities beyond 70 kW/l opens up new options for smaller charge volumes. A low-pressure and a high-pressure supercharger are connected in series, with by-passes. The control strategy is described in this contribution using a model of exhaust counterpressure. The potential of a two-stage supercharged diesel engine with CR injection was proved in two engines and in dynamic driving tests. The new concept offers optimum chances for downsizing provided that the driving performance is not affected. (orig.) [German] Die zweistufige Aufladung von Verbrennungsmotoren eroeffnet mit spezifischen Leistungen jenseits von 70 kW/l weitere Moeglichkeiten der Hubraumverkleinerung. Dabei werden ein Niederdruck- und ein Hochdrucklader mit Umgehungsleitungen in Reihe geschaltet. Die erforderliche Regelungsstrategie zum kontrollierten Uebergang von einer Stufe auf die naechste erfolgt in dem hier vorliegenden Beitrag anhand eines Modells fuer den Abgasgegendruck. Hierbei wird das Regelorgan so angesteuert, dass sich der gewuenschte Druck vor den Turbinen einstellt. An zwei Motoren konnten stationaere Ergebnisse das Leistungspotential eines zweistufig aufgeladenen Dieselmotors mit 'Common Rail' Einspritzung nachgewiesen werden. Die dynamischen Fahrversuche belegen eindrucksvoll den schnellen Ladedruckaufbau auch aus tiefen Drehzahlbereichen bei gleichzeitig gutem Uebergangsverhalten von der Hochdruck- auf die Niederdruckstufe. Damit bietet der zweistufig aufgeladene Dieselmotor mit dem hier dargestellten Regelungsverfahren optimale Voraussetzungen fuer 'Downsizing' unter der Randbedingung, dass moeglichst keine Einbussen bei den Fahrleistungen hinzunehmen sind. (orig.)

Transport fuels from two-stage coal liquefaction

Energy Technology Data Exchange (ETDEWEB)

Benito, A.; Cebolla, V.; Fernandez, I.; Martinez, M.T.; Miranda, J.L.; Oelert, H.; Prado, J.G. (Instituto de Carboquimica CSIC, Zaragoza (Spain))

1994-03-01

Four Spanish lignites and their vitrinite concentrates were evaluated for coal liquefaction. Correlationships between the content of vitrinite and conversion in direct liquefaction were observed for the lignites but not for the vitrinite concentrates. The most reactive of the four coals was processed in two-stage liquefaction at a higher scale. First-stage coal liquefaction was carried out in a continuous unit at Clausthal University at a temperature of 400[degree]C at 20 MPa hydrogen pressure and with anthracene oil as a solvent. The coal conversion obtained was 75.41% being 3.79% gases, 2.58% primary condensate and 69.04% heavy liquids. A hydroprocessing unit was built at the Instituto de Carboquimica for the second-stage coal liquefaction. Whole and deasphalted liquids from the first-stage liquefaction were processed at 450[degree]C and 10 MPa hydrogen pressure, with two commercial catalysts: Harshaw HT-400E (Co-Mo/Al[sub 2]O[sub 3]) and HT-500E (Ni-Mo/Al[sub 2]O[sub 3]). The effects of liquid hourly space velocity (LHSV), temperature, gas/liquid ratio and catalyst on the heteroatom liquids, and levels of 5 ppm of nitrogen and 52 ppm of sulphur were reached at 450[degree]C, 10 MPa hydrogen pressure, 0.08 kg H[sub 2]/kg feedstock and with Harshaw HT-500E catalyst. The liquids obtained were hydroprocessed again at 420[degree]C, 10 MPa hydrogen pressure and 0.06 kg H[sub 2]/kg feedstock to hydrogenate the aromatic structures. In these conditions, the aromaticity was reduced considerably, and 39% of naphthas and 35% of kerosene fractions were obtained. 18 refs., 4 figs., 4 tabs.

Maximally efficient two-stage screening: Determining intellectual disability in Taiwanese military conscripts

Directory of Open Access Journals (Sweden)

Chia-Chang Chien

2009-01-01

Full Text Available Chia-Chang Chien1, Shu-Fen Huang1,2,3,4, For-Wey Lung1,2,3,41Department of Psychiatry, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan; 2Graduate Institute of Behavioral Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; 3Department of Psychiatry, National Defense Medical Center, Taipei, Taiwan; 4Calo Psychiatric Center, Pingtung County, TaiwanObjective: The purpose of this study was to apply a two-stage screening method for the large-scale intelligence screening of military conscripts.Methods: We collected 99 conscripted soldiers whose educational levels were senior high school level or lower to be the participants. Every participant was required to take the Wisconsin Card Sorting Test (WCST and the Wechsler Adult Intelligence Scale-Revised (WAIS-R assessments.Results: Logistic regression analysis showed the conceptual level responses (CLR index of the WCST was the most significant index for determining intellectual disability (ID; FIQ ≤ 84. We used the receiver operating characteristic curve to determine the optimum cut-off point of CLR. The optimum one cut-off point of CLR was 66; the two cut-off points were 49 and 66. Comparing the two-stage window screening with the two-stage positive screening, the area under the curve and the positive predictive value increased. Moreover, the cost of the two-stage window screening decreased by 59%.Conclusion: The two-stage window screening is more accurate and economical than the two-stage positive screening. Our results provide an example for the use of two-stage screening and the possibility of the WCST to replace WAIS-R in large-scale screenings for ID in the future.Keywords: intellectual disability, intelligence screening, two-stage positive screening, Wisconsin Card Sorting Test, Wechsler Adult Intelligence Scale-Revised

Two-stage model of development of heterogeneous uranium-lead systems in zircon

International Nuclear Information System (INIS)

Mel'nikov, N.N.; Zevchenkov, O.A.

1985-01-01

Behaviour of isotope systems of multiphase zircons at their two-stage distortion is considered. The results of calculations testify to the fact that linear correlations on the diagram with concordance can be explained including two-stage discovery of U-Pb systems of cogenetic zircons if zircon is considered physically heterogeneous and losing in its different part different ratios of accumulated radiogenic lead. ''Metamorphism ages'' obtained by these two-stage opening zircons are intermediate, and they not have geochronological significance while ''crystallization ages'' remain rather close to real ones. Two-stage opening zircons in some cases can be diagnosed by discordance of their crystal component

Two technicians apply insulation to S-II second stage

Science.gov (United States)

1964-01-01

Two technicians apply insulation to the outer surface of the S-II second stage booster for the Saturn V moon rocket. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

Target volume delineation variation in radiotherapy for early stage rectal cancer in the Netherlands

International Nuclear Information System (INIS)

Nijkamp, Jasper; Haas-Kock, Danielle F.M. de; Beukema, Jannet C.; Neelis, Karen J.; Woutersen, Dankert; Ceha, Heleen; Rozema, Tom; Slot, Annerie; Vos-Westerman, Hanneke; Intven, Martijn; Spruit, Patty H.; Linden, Yvette van der; Geijsen, Debby; Verschueren, Karijn; Herk, Marcel B. van; Marijnen, Corrie A.M.

2012-01-01

Purpose: The aim of this study was to measure and improve the quality of target volume delineation by means of national consensus on target volume definition in early-stage rectal cancer. Methods and materials: The CTV’s for eight patients were delineated by 11 radiation oncologists in 10 institutes according to local guidelines (phase 1). After observer variation analysis a workshop was organized to establish delineation guidelines and a digital atlas, with which the same observers re-delineated the dataset (phase 2). Variation in volume, most caudal and cranial slice and local surface distance variation were analyzed. Results: The average delineated CTV volume decreased from 620 to 460 cc (p < 0.001) in phase 2. Variation in the caudal CTV border was reduced significantly from 1.8 to 1.2 cm SD (p = 0.01), while it remained 0.7 cm SD for the cranial border. The local surface distance variation (cm SD) reduced from 1.02 to 0.74 for anterior, 0.63 to 0.54 for lateral, 0.33 to 0.25 for posterior and 1.22 to 0.46 for the sphincter region, respectively. Conclusions: The large variation in target volume delineation could significantly be reduced by use of consensus guidelines and a digital delineation atlas. Despite the significant reduction there is still a need for further improvement.

Bayesian enhancement two-stage design for single-arm phase II clinical trials with binary and time-to-event endpoints.

Science.gov (United States)

Shi, Haolun; Yin, Guosheng

2018-02-21

Simon's two-stage design is one of the most commonly used methods in phase II clinical trials with binary endpoints. The design tests the null hypothesis that the response rate is less than an uninteresting level, versus the alternative hypothesis that the response rate is greater than a desirable target level. From a Bayesian perspective, we compute the posterior probabilities of the null and alternative hypotheses given that a promising result is declared in Simon's design. Our study reveals that because the frequentist hypothesis testing framework places its focus on the null hypothesis, a potentially efficacious treatment identified by rejecting the null under Simon's design could have only less than 10% posterior probability of attaining the desirable target level. Due to the indifference region between the null and alternative, rejecting the null does not necessarily mean that the drug achieves the desirable response level. To clarify such ambiguity, we propose a Bayesian enhancement two-stage (BET) design, which guarantees a high posterior probability of the response rate reaching the target level, while allowing for early termination and sample size saving in case that the drug's response rate is smaller than the clinically uninteresting level. Moreover, the BET design can be naturally adapted to accommodate survival endpoints. We conduct extensive simulation studies to examine the empirical performance of our design and present two trial examples as applications. © 2018, The International Biometric Society.

Hydrogen and methane production from condensed molasses fermentation soluble by a two-stage anaerobic process

Energy Technology Data Exchange (ETDEWEB)

Lin, Chiu-Yue; Liang, You-Chyuan; Lay, Chyi-How [Feng Chia Univ., Taichung, Taiwan (China). Dept. of Environmental Engineering and Science; Chen, Chin-Chao [Chungchou Institute of Technology, Taiwan (China). Environmental Resources Lab.; Chang, Feng-Yuan [Feng Chia Univ., Taichung, Taiwan (China). Research Center for Energy and Resources

2010-07-01

The treatment of condensed molasses fermentation soluble (CMS) is a troublesome problem for glutamate manufacturing factory. However, CMS contains high carbohydrate and nutrient contents and is an attractive and commercially potential feedstock for bioenergy production. The aim of this paper is to produce hydrogen and methane by two-stage anaerobic fermentation process. The fermentative hydrogen production from CMS was conducted in a continuously-stirred tank bioreactor (working volume 4 L) which was operated at a hydraulic retention time (HRT) of 8 h, organic loading rate (OLR) of 120 kg COD/m{sup 3}-d, temperature of 35 C, pH 5.5 and sewage sludge as seed. The anaerobic methane production was conducted in an up-flow bioreactor (working volume 11 L) which was operated at a HRT of 24 -60 hrs, OLR of 4.0-10 kg COD/m{sup 3}-d, temperature of 35 C, pH 7.0 with using anaerobic granule sludge from fructose manufacturing factory as the seed and the effluent from hydrogen production process as the substrate. These two reactors have been operated successfully for more than 400 days. The steady-state hydrogen content, hydrogen production rate and hydrogen production yield in the hydrogen fermentation system were 37%, 169 mmol-H{sub 2}/L-d and 93 mmol-H{sub 2}/g carbohydrate{sub removed}, respectively. In the methane fermentation system, the peak methane content and methane production rate were 66.5 and 86.8 mmol-CH{sub 4}/L-d with methane production yield of 189.3 mmol-CH{sub 4}/g COD{sub removed} at an OLR 10 kg/m{sup 3}-d. The energy production rate was used to elucidate the energy efficiency for this two-stage process. The total energy production rate of 133.3 kJ/L/d was obtained with 5.5 kJ/L/d from hydrogen fermentation and 127.8 kJ/L/d from methane fermentation. (orig.)

Non-ideal magnetohydrodynamic simulations of the two-stage fragmentation model for cluster formation

International Nuclear Information System (INIS)

Bailey, Nicole D.; Basu, Shantanu

2014-01-01

We model molecular cloud fragmentation with thin-disk, non-ideal magnetohydrodynamic simulations that include ambipolar diffusion and partial ionization that transitions from primarily ultraviolet-dominated to cosmic-ray-dominated regimes. These simulations are used to determine the conditions required for star clusters to form through a two-stage fragmentation scenario. Recent linear analyses have shown that the fragmentation length scales and timescales can undergo a dramatic drop across the column density boundary that separates the ultraviolet- and cosmic-ray-dominated ionization regimes. As found in earlier studies, the absence of an ionization drop and regular perturbations leads to a single-stage fragmentation on pc scales in transcritical clouds, so that the nonlinear evolution yields the same fragment sizes as predicted by linear theory. However, we find that a combination of initial transcritical mass-to-flux ratio, evolution through a column density regime in which the ionization drop takes place, and regular small perturbations to the mass-to-flux ratio is sufficient to cause a second stage of fragmentation during the nonlinear evolution. Cores of size ∼0.1 pc are formed within an initial fragment of ∼pc size. Regular perturbations to the mass-to-flux ratio also accelerate the onset of runaway collapse.

Cervical Vertebral Body's Volume as a New Parameter for Predicting the Skeletal Maturation Stages

OpenAIRE

Choi, Youn-Kyung; Kim, Jinmi; Yamaguchi, Tetsutaro; Maki, Koutaro; Ko, Ching-Chang; Kim, Yong-Il

2016-01-01

This study aimed to determine the correlation between the volumetric parameters derived from the images of the second, third, and fourth cervical vertebrae by using cone beam computed tomography with skeletal maturation stages and to propose a new formula for predicting skeletal maturation by using regression analysis. We obtained the estimation of skeletal maturation levels from hand-wrist radiographs and volume parameters derived from the second, third, and fourth cervical vertebrae bodies ...

High-Speed 3D Printing of High-Performance Thermosetting Polymers via Two-Stage Curing.

Science.gov (United States)

Kuang, Xiao; Zhao, Zeang; Chen, Kaijuan; Fang, Daining; Kang, Guozheng; Qi, Hang Jerry

2018-04-01

Design and direct fabrication of high-performance thermosets and composites via 3D printing are highly desirable in engineering applications. Most 3D printed thermosetting polymers to date suffer from poor mechanical properties and low printing speed. Here, a novel ink for high-speed 3D printing of high-performance epoxy thermosets via a two-stage curing approach is presented. The ink containing photocurable resin and thermally curable epoxy resin is used for the digital light processing (DLP) 3D printing. After printing, the part is thermally cured at elevated temperature to yield an interpenetrating polymer network epoxy composite, whose mechanical properties are comparable to engineering epoxy. The printing speed is accelerated by the continuous liquid interface production assisted DLP 3D printing method, achieving a printing speed as high as 216 mm h -1 . It is also demonstrated that 3D printing structural electronics can be achieved by combining the 3D printed epoxy composites with infilled silver ink in the hollow channels. The new 3D printing method via two-stage curing combines the attributes of outstanding printing speed, high resolution, low volume shrinkage, and excellent mechanical properties, and provides a new avenue to fabricate 3D thermosetting composites with excellent mechanical properties and high efficiency toward high-performance and functional applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-stage anaerobic treatment of non-settled slaughterhouse waste water using a fixed-bed reactor. Einstufige anaerobe Behandlung von nicht abgesetztem Schlachthofabwasser in einem Festbettreaktor

Energy Technology Data Exchange (ETDEWEB)

Tritt, W.P. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany). Inst. fuer Technologie); Meyer-Jacob, H.

1992-01-01

Along with the determination of the degree of acidification during an intermediate storage of the crude slaughterhouse wastewater and deriving a single-stage or two-stage process, the start-up behaviour of the fixed-bed reactor, its degradation rates in upflow and downflow operation is descirbed. With regard to a subsequent biological denitrification the COD/N ratio of anaerobically treated wastewater is given. (orig.).

Two-stage case-control association study of dopamine-related genes and migraine

Directory of Open Access Journals (Sweden)

Pardo Julio

2009-09-01

Full Text Available Abstract Background We previously reported risk haplotypes for two genes related with serotonin and dopamine metabolism: MAOA in migraine without aura and DDC in migraine with aura. Herein we investigate the contribution to migraine susceptibility of eight additional genes involved in dopamine neurotransmission. Methods We performed a two-stage case-control association study of 50 tag single nucleotide polymorphisms (SNPs, selected according to genetic coverage parameters. The first analysis consisted of 263 patients and 274 controls and the replication study was composed by 259 cases and 287 controls. All cases were diagnosed according to ICHD-II criteria, were Spanish Caucasian, and were sex-matched with control subjects. Results Single-marker analysis of the first population identified nominal associations of five genes with migraine. After applying a false discovery rate correction of 10%, the differences remained significant only for DRD2 (rs2283265 and TH (rs2070762. Multiple-marker analysis identified a five-marker T-C-G-C-G (rs12363125-rs2283265-rs2242592-rs1554929-rs2234689 risk haplotype in DRD2 and a two-marker A-C (rs6356-rs2070762 risk haplotype in TH that remained significant after correction by permutations. These results, however, were not replicated in the second independent cohort. Conclusion The present study does not support the involvement of the DRD1, DRD2, DRD3, DRD5, DBH, COMT, SLC6A3 and TH genes in the genetic predisposition to migraine in the Spanish population.

Investigation of Power Losses of Two-Stage Two-Phase Converter with Two-Phase Motor

Directory of Open Access Journals (Sweden)

Michal Prazenica

2011-01-01

Full Text Available The paper deals with determination of losses of two-stage power electronic system with two-phase variable orthogonal output. The simulation is focused on the investigation of losses in the converter during one period in steady-state operation. Modeling and simulation of two matrix converters with R-L load is shown in the paper. The simulation results confirm a very good time-waveform of the phase current and the system seems to be suitable for low-cost application in automotive/aerospace industries and in application with high frequency voltage sources.

Single-stage laparoscopic common bile duct exploration and cholecystectomy versus two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy for patients with gallbladder stones with common bile duct stones: systematic review and meta-analysis of randomized trials with trial sequential analysis.

Science.gov (United States)

Singh, Anand Narayan; Kilambi, Ragini

2018-03-30

The ideal management of common bile duct (CBD) stones associated with gall stones is a matter of debate. We planned a meta-analysis of randomized trials comparing single-stage laparoscopic CBD exploration and cholecystectomy (LCBDE) with two-stage preoperative endoscopic stone extraction followed by cholecystectomy (ERCP + LC). We searched the Pubmed/Medline, Web of science, Science citation index, Google scholar and Cochrane Central Register of Controlled trials electronic databases till June 2017 for all English language randomized trials comparing the two approaches. Statistical analysis was performed using Review Manager (RevMan) [Computer program], Version 5.3. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014 and results were expressed as odds ratio for dichotomous variables and mean difference for continuous. p value ≤ 0.05 was considered significant. Trial sequential analysis (TSA) was performed using TSA version 0.9.5.5 (Copenhagen: The Copenhagen Trial Unit, Centre for Clinical Intervention Research, 2016). PROSPERO trial registration number is CRD42017074673. A total of 11 trials were included in the analysis, with a total of 1513 patients (751-LCBDE; 762-ERCP + LC). LCBDE was found to have significantly lower rates of technical failure [OR 0.59, 95% CI (0.38, 0.93), p = 0.02] and shorter hospital stay [MD - 1.63, 95% CI (- 3.23, - 0.03), p = 0.05]. There was no significant difference in mortality [OR 0.37, 95% CI (0.09, 1.51), p = 0.17], morbidity [OR 0.97, 95% CI (0.70, 1.33), p = 0.84], cost [MD - 379.13, 95% CI (- 784.80, 111.2), p = 0.13] or recurrent/retained stones [OR 1.01, 95% CI (0.38, 2.73), p = 0.98]. TSA showed that although the Z-curve crossed the boundaries of conventional significance, the estimated information size is yet to be achieved. Single-stage LCBDE is superior to ERCP + LC in terms of technical success and shorter hospital stay in good-risk patients with

Evidence that viral RNAs have evolved for efficient, two-stage packaging.

Science.gov (United States)

Borodavka, Alexander; Tuma, Roman; Stockley, Peter G

2012-09-25

Genome packaging is an essential step in virus replication and a potential drug target. Single-stranded RNA viruses have been thought to encapsidate their genomes by gradual co-assembly with capsid subunits. In contrast, using a single molecule fluorescence assay to monitor RNA conformation and virus assembly in real time, with two viruses from differing structural families, we have discovered that packaging is a two-stage process. Initially, the genomic RNAs undergo rapid and dramatic (approximately 20-30%) collapse of their solution conformations upon addition of cognate coat proteins. The collapse occurs with a substoichiometric ratio of coat protein subunits and is followed by a gradual increase in particle size, consistent with the recruitment of additional subunits to complete a growing capsid. Equivalently sized nonviral RNAs, including high copy potential in vivo competitor mRNAs, do not collapse. They do support particle assembly, however, but yield many aberrant structures in contrast to viral RNAs that make only capsids of the correct size. The collapse is specific to viral RNA fragments, implying that it depends on a series of specific RNA-protein interactions. For bacteriophage MS2, we have shown that collapse is driven by subsequent protein-protein interactions, consistent with the RNA-protein contacts occurring in defined spatial locations. Conformational collapse appears to be a distinct feature of viral RNA that has evolved to facilitate assembly. Aspects of this process mimic those seen in ribosome assembly.

Genomic Prediction of Single Crosses in the Early Stages of a Maize Hybrid Breeding Pipeline

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Dnyaneshwar C. Kadam

2016-11-01

Full Text Available Prediction of single-cross performance has been a major goal of plant breeders since the beginning of hybrid breeding. Recently, genomic prediction has shown to be a promising approach, but only limited studies have examined the accuracy of predicting single-cross performance. Moreover, no studies have examined the potential of predicting single crosses among random inbreds derived from a series of biparental families, which resembles the structure of germplasm comprising the initial stages of a hybrid maize breeding pipeline. The main objectives of this study were to evaluate the potential of genomic prediction for identifying superior single crosses early in the hybrid breeding pipeline and optimize its application. To accomplish these objectives, we designed and analyzed a novel population of single crosses representing the Iowa Stiff Stalk synthetic/non-Stiff Stalk heterotic pattern commonly used in the development of North American commercial maize hybrids. The performance of single crosses was predicted using parental combining ability and covariance among single crosses. Prediction accuracies were estimated using cross-validation and ranged from 0.28 to 0.77 for grain yield, 0.53 to 0.91 for plant height, and 0.49 to 0.94 for staygreen, depending on the number of tested parents of the single cross and genomic prediction method used. The genomic estimated general and specific combining abilities showed an advantage over genomic covariances among single crosses when one or both parents of the single cross were untested. Overall, our results suggest that genomic prediction of single crosses in the early stages of a hybrid breeding pipeline holds great potential to redesign hybrid breeding and increase its efficiency.

Device for two-stage cementing of casing

Energy Technology Data Exchange (ETDEWEB)

Kudimov, D A; Goncharevskiy, Ye N; Luneva, L G; Shchelochkov, S N; Shil' nikova, L N; Tereshchenko, V G; Vasiliev, V A; Volkova, V V; Zhdokov, K I

1981-01-01

A device is claimed for two-stage cementing of casing. It consists of a body with lateral plugging vents, upper and lower movable sleeves, a check valve with axial channels that's situated in the lower sleeve, and a displacement limiting device for the lower sleeve. To improve the cementing process of the casing by preventing overflow of cementing fluids from the annular space into the first stage casing, the limiter is equipped with a spring rod that is capable of covering the axial channels of the check valve while it's in an operating mode. In addition, the rod in the upper part is equipped with a reinforced area under the axial channels of the check valve.

Cervical Vertebral Body's Volume as a New Parameter for Predicting the Skeletal Maturation Stages.

Science.gov (United States)

Choi, Youn-Kyung; Kim, Jinmi; Yamaguchi, Tetsutaro; Maki, Koutaro; Ko, Ching-Chang; Kim, Yong-Il

2016-01-01

This study aimed to determine the correlation between the volumetric parameters derived from the images of the second, third, and fourth cervical vertebrae by using cone beam computed tomography with skeletal maturation stages and to propose a new formula for predicting skeletal maturation by using regression analysis. We obtained the estimation of skeletal maturation levels from hand-wrist radiographs and volume parameters derived from the second, third, and fourth cervical vertebrae bodies from 102 Japanese patients (54 women and 48 men, 5-18 years of age). We performed Pearson's correlation coefficient analysis and simple regression analysis. All volume parameters derived from the second, third, and fourth cervical vertebrae exhibited statistically significant correlations (P cervical-vertebra volume as an independent variable with a variance inflation factor less than ten. The explanation power was 81.76%. Volumetric parameters of cervical vertebrae using cone beam computed tomography are useful in regression models. The derived regression model has the potential for clinical application as it enables a simple and quantitative analysis to evaluate skeletal maturation level.

Performance of the rebuilt SUERC single-stage accelerator mass spectrometer

Science.gov (United States)

Shanks, Richard P.; Ascough, Philippa L.; Dougans, Andrew; Gallacher, Paul; Gulliver, Pauline; Rood, Dylan H.; Xu, Sheng; Freeman, Stewart P. H. T.

2015-10-01

The SUERC bipolar single-stage accelerator mass spectrometer (SSAMS) has been dismantled and rebuilt to accommodate an additional rotatable pre-accelerator electrostatic spherical analyser (ESA) and a second ion source injector. This is for the attachment of an experimental positive-ion electron cyclotron resonance (ECR) ion source in addition to a Cs-sputter source. The ESA significantly suppresses oxygen interference to radiocarbon detection, and remaining measurement interference is now thought to be from 13C injected as 13CH molecule scattering off the plates of a second original pre-detector ESA.

Optimization of Two-Stage Peltier Modules: Structure and Exergetic Efficiency

Directory of Open Access Journals (Sweden)

Cesar Ramirez-Lopez

2012-08-01

Full Text Available In this paper we undertake the theoretical analysis of a two-stage semiconductor thermoelectric module (TEM which contains an arbitrary and different number of thermocouples, n₁ and n₂, in each stage (pyramid-styled TEM. The analysis is based on a dimensionless entropy balance set of equations. We study the effects of n₁ and n₂, the flowing electric currents through each stage, the applied temperatures and the thermoelectric properties of the semiconductor materials on the exergetic efficiency. Our main result implies that the electric currents flowing in each stage must necessarily be different with a ratio about 4.3 if the best thermal performance and the highest temperature difference possible between the cold and hot side of the device are pursued. This fact had not been pointed out before for pyramid-styled two stage TEM. The ratio n₁/n₂ should be about 8.

Two convenient low-temperature routes to single crystals of plutonium dioxide

Energy Technology Data Exchange (ETDEWEB)

Meredith, Nathan A. [Departments of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Wang, Shuao; Diwu, Juan [School of Radiation Medicine and Protection and School of Radiological and Interdisciplinary Sciences, Soochow University, Suzhou, Jiangsu 215123 (China); Albrecht-Schmitt, Thomas E., E-mail: talbrechtschmitt@gmail.com [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States)

2014-11-15

Highlights: • Two low-temperature routes to the growth single crystals of plutonium dioxide. • Safer methods of preparing PuO{sub 2} single crystals that do not involve solid-state synthetic techniques. • Solvothermal crystal growth of plutonium dioxide. - Abstract: During the solvothermal synthesis of a low-dimensional borate, KB{sub 5}O{sub 7}(OH){sub 2}⋅2H{sub 2}O, in the presence of Pu(III), single crystals of plutonium dioxide unexpectedly formed. Single crystals of PuO{sub 2} also formed during the hydrothermal synthesis of another borate, Na{sub 2}B{sub 5}O{sub 8}(OH)⋅2H{sub 2}O, in the presence of Pu(III). The reactions were conducted at 170 °C and 150 °C, respectively, which are much lower temperature than previously reported preparations of crystalline PuO{sub 2}. Yellow–green crystals with a tablet habit were characterized by single crystal X-ray diffraction and solid-state UV–vis–NIR absorption spectroscopy. The crystal structure was solved by direct methods with R{sub 1} = 1.26% for 19 unique observed reflections. PuO{sub 2} is cubic, space group Fm3{sup ‾}m, and adopts the fluorite structure type. The lattice parameter was determined to be a = 5.421(5) Å giving a volume of 159.3(2) Å{sup 3}. The absorption spectrum is consistent with Pu(IV)

Two stage treatment of dairy effluent using immobilized Chlorella pyrenoidosa

Science.gov (United States)

2013-01-01

Background Dairy effluents contains high organic load and unscrupulous discharge of these effluents into aquatic bodies is a matter of serious concern besides deteriorating their water quality. Whilst physico-chemical treatment is the common mode of treatment, immobilized microalgae can be potentially employed to treat high organic content which offer numerous benefits along with waste water treatment. Methods A novel low cost two stage treatment was employed for the complete treatment of dairy effluent. The first stage consists of treating the diary effluent in a photobioreactor (1 L) using immobilized Chlorella pyrenoidosa while the second stage involves a two column sand bed filtration technique. Results Whilst NH4+-N was completely removed, a 98% removal of PO43--P was achieved within 96 h of two stage purification processes. The filtrate was tested for toxicity and no mortality was observed in the zebra fish which was used as a model at the end of 96 h bioassay. Moreover, a significant decrease in biological oxygen demand and chemical oxygen demand was achieved by this novel method. Also the biomass separated was tested as a biofertilizer to the rice seeds and a 30% increase in terms of length of root and shoot was observed after the addition of biomass to the rice plants. Conclusions We conclude that the two stage treatment of dairy effluent is highly effective in removal of BOD and COD besides nutrients like nitrates and phosphates. The treatment also helps in discharging treated waste water safely into the receiving water bodies since it is non toxic for aquatic life. Further, the algal biomass separated after first stage of treatment was highly capable of increasing the growth of rice plants because of nitrogen fixation ability of the green alga and offers a great potential as a biofertilizer. PMID:24355316

Numerical simulation of stage separation of a multi-stage flying object with brake jets

International Nuclear Information System (INIS)

Mirzaei, M.; Shadaram, A.; Nia, B.N.

2005-01-01

In this paper, separation maneuver of a two-stage supersonic flying object is numerically simulated and the influences of supersonic brake jets on separation process are discussed. The finite volume approach is used for solution of unsteady three-dimensional full Navier-Stokes equations on a moving boundary domain. In this simulation, air has considered as a calorically perfect gas and since the flow field is turbulent, two equations κ-ε model has been adopted for turbulence modeling. Shocks, expansions and their reflections have major role on flow pattern between two stages during the separation process and the maneuver is dominantly affected by the main flow and braking jets. The separation process has an unsteady nature and the separation of stages at high Mach numbers induces some aerodynamic problems that may lead to fail the next stage flight. The purpose of this research is to compute the aerodynamic loads on separated stage and, consequently, the relative distance of body components with a good accuracy. The simulation of moving boundary problem is based on moving grid strategy using remeshing method. To validate the simulation, some of the results are compared with experimental data. (author)

Two-Stage Liver Transplantation with Temporary Porto-Middle Hepatic Vein Shunt

Directory of Open Access Journals (Sweden)

Giovanni Varotti

2010-01-01

Full Text Available Two-stage liver transplantation (LT has been reported for cases of fulminant liver failure that can lead to toxic hepatic syndrome, or massive hemorrhages resulting in uncontrollable bleeding. Technically, the first stage of the procedure consists of a total hepatectomy with preservation of the recipient's inferior vena cava (IVC, followed by the creation of a temporary end-to-side porto-caval shunt (TPCS. The second stage consists of removing the TPCS and implanting a liver graft when one becomes available. We report a case of a two-stage total hepatectomy and LT in which a temporary end-to-end anastomosis between the portal vein and the middle hepatic vein (TPMHV was performed as an alternative to the classic end-to-end TPCS. The creation of a TPMHV proved technically feasible and showed some advantages compared to the standard TPCS. In cases in which a two-stage LT with side-to-side caval reconstruction is utilized, TPMHV can be considered as a safe and effective alternative to standard TPCS.

Two-stage perceptual learning to break visual crowding.

Science.gov (United States)

Zhu, Ziyun; Fan, Zhenzhi; Fang, Fang

2016-01-01

When a target is presented with nearby flankers in the peripheral visual field, it becomes harder to identify, which is referred to as crowding. Crowding sets a fundamental limit of object recognition in peripheral vision, preventing us from fully appreciating cluttered visual scenes. We trained adult human subjects on a crowded orientation discrimination task and investigated whether crowding could be completely eliminated by training. We discovered a two-stage learning process with this training task. In the early stage, when the target and flankers were separated beyond a certain distance, subjects acquired a relatively general ability to break crowding, as evidenced by the fact that the breaking of crowding could transfer to another crowded orientation, even a crowded motion stimulus, although the transfer to the opposite visual hemi-field was weak. In the late stage, like many classical perceptual learning effects, subjects' performance gradually improved and showed specificity to the trained orientation. We also found that, when the target and flankers were spaced too finely, training could only reduce, rather than completely eliminate, the crowding effect. This two-stage learning process illustrates a learning strategy for our brain to deal with the notoriously difficult problem of identifying peripheral objects in clutter. The brain first learned to solve the "easy and general" part of the problem (i.e., improving the processing resolution and segmenting the target and flankers) and then tackle the "difficult and specific" part (i.e., refining the representation of the target).

Chromium (Ⅵ) removal from aqueous solutions through powdered activated carbon countercurrent two-stage adsorption.

Science.gov (United States)

Wang, Wenqiang

2018-01-01

To exploit the adsorption capacity of commercial powdered activated carbon (PAC) and to improve the efficiency of Cr(VI) removal from aqueous solutions, the adsorption of Cr(VI) by commercial PAC and the countercurrent two-stage adsorption (CTA) process was investigated. Different adsorption kinetics models and isotherms were compared, and the pseudo-second-order model and the Langmuir and Freundlich models fit the experimental data well. The Cr(VI) removal efficiency was >80% and was improved by 37% through the CTA process compared with the conventional single-stage adsorption process when the initial Cr(VI) concentration was 50 mg/L with a PAC dose of 1.250 g/L and a pH of 3. A calculation method for calculating the effluent Cr(VI) concentration and the PAC dose was developed for the CTA process, and the validity of the method was confirmed by a deviation of <5%. Copyright © 2017. Published by Elsevier Ltd.

Investigation of Advanced Propellants to Enable Single Stage to Orbit Launch Vehicles

Science.gov (United States)

2006-10-30

ERS-PAS-2006-205) 13. SUPPLEMENTARY NOTES Graduate work for California State University, Fresno 14. ABSTRACT Single-Stage-To-Orbit ( SSTO ...and maintained. Despite well-funded development efforts, no SSTO vehicles have been fielded to date. Existing chemical rocket and vehicle...technologies do not enable feasible SSTO designs. In the future, new propellants with advanced properties could enable SSTO launch vehicles. A parametric

Multi-staged robotic stereotactic radiosurgery for large cerebral arteriovenous malformations

International Nuclear Information System (INIS)

Ding, Chuxiong; Solberg, Timothy D.; Hrycushko, Brian; Medin, Paul; Whitworth, Louis; Timmerman, Robert D.

2013-01-01

Purpose: To investigate a multi-staged robotic stereotactic radiosurgery (SRS) delivery technique for the treatment of large cerebral arteriovenous malformations (AVMs). The treatment planning process and strategies to optimize both individual and composite dosimetry are discussed. Methods: Eleven patients with large (30.7 ± 19.2 cm 3 ) AVMs were selected for this study. A fiducial system was designed for fusion of targets between planar angiograms and simulation CT scans. AVMs were contoured based on single contrast CT, MRI and orthogonal angiogram images. AVMs were divided into 3–8 sub-target volumes (3–7 cm 3 ) for sequential treatment at 1–4 week intervals to a prescription dose of 16–20 Gy. Forward and inversely developed treatment plans were optimized for 95% coverage of the total AVM volume by dose summation from each sub-volume, while minimizing dose to surrounding tissues. Dose-volume analysis was used to evaluate the PTV coverage, dose conformality (CI), and R 50 and V 12Gy parameters. Results: The treatment workflow was commissioned and able to localize within 1 mm. Inverse optimization outperformed forward planning for most patients for each index considered. Dose conformality was shown comparable to staged Gamma Knife treatments. Conclusion: The CyberKnife system is shown to be a practical delivery platform for multi-staged treatments of large AVMs using forward or inverse planning techniques

Research on Two-channel Interleaved Two-stage Paralleled Buck DC-DC Converter for Plasma Cutting Power Supply

DEFF Research Database (Denmark)

Yang, Xi-jun; Qu, Hao; Yao, Chen

2014-01-01

As for high power plasma power supply, due to high efficiency and flexibility, multi-channel interleaved multi-stage paralleled Buck DC-DC Converter becomes the first choice. In the paper, two-channel interleaved two- stage paralleled Buck DC-DC Converter powered by three-phase AC power supply...

Production of endo-pectate lyase by two stage cultivation of Erwinia carotovora

Energy Technology Data Exchange (ETDEWEB)

Fukuoka, Satoshi; Kobayashi, Yoshiaki

1987-02-26

The productivity of endo-pectate lyase from Erwinia carotovora GIR 1044 was found to be greatly improved by two stage cultivation: in the first stage the bacterium was grown with an inducing carbon source, e.g., pectin, and in the second stage it was cultivated with glycerol, xylose, or fructose with the addition of monosodium L-glutamate as nitrogen source. In the two stage cultivation using pectin or glycerol as the carbon source the enzyme activity reached 400 units/ml, almost 3 times as much as that of one stage cultivation in a 10 liter fermentor. Using two stage cultivation in the 200 liter fermentor improved enzyme productivity over that in the 10 liter fermentor, with 500 units/ml of activity. Compared with the cultivation in Erlenmeyer flasks, fermentor cultivation improved enzyme productivity. The optimum cultivating conditions were agitation of 480 rpm with aeration of 0.5 vvm at 28 /sup 0/C. (4 figs, 4 tabs, 14 refs)

A farm-scale pilot plant for biohydrogen and biomethane production by two-stage fermentation

Directory of Open Access Journals (Sweden)

R. Oberti

2013-09-01

Full Text Available Hydrogen is considered one of the possible main energy carriers for the future, thanks to its unique environmental properties. Indeed, its energy content (120 MJ/kg can be exploited virtually without emitting any exhaust in the atmosphere except for water. Renewable production of hydrogen can be obtained through common biological processes on which relies anaerobic digestion, a well-established technology in use at farm-scale for treating different biomass and residues. Despite two-stage hydrogen and methane producing fermentation is a simple variant of the traditional anaerobic digestion, it is a relatively new approach mainly studied at laboratory scale. It is based on biomass fermentation in two separate, seuqential stages, each maintaining conditions optimized to promote specific bacterial consortia: in the first acidophilic reactorhydrogen is produced production, while volatile fatty acids-rich effluent is sent to the second reactor where traditional methane rich biogas production is accomplished. A two-stage pilot-scale plant was designed, manufactured and installed at the experimental farm of the University of Milano and operated using a biomass mixture of livestock effluents mixed with sugar/starch-rich residues (rotten fruits and potatoes and expired fruit juices, afeedstock mixture based on waste biomasses directly available in the rural area where plant is installed. The hydrogenic and the methanogenic reactors, both CSTR type, had a total volume of 0.7m3 and 3.8 m3 respectively, and were operated in thermophilic conditions (55 2 °C without any external pH control, and were fully automated. After a brief description of the requirements of the system, this contribution gives a detailed description of its components and of engineering solutions to the problems encountered during the plant realization and start-up. The paper also discusses the results obtained in a first experimental run which lead to production in the range of previous

High-risk clinical target volume delineation in CT-guided cervical cancer brachytherapy - Impact of information from FIGO stage with or without systematic inclusion of 3D documentation of clinical gynecological examination

Energy Technology Data Exchange (ETDEWEB)

Hegazy, Neamat [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria); Dept. of Clinical Oncology, Medical Univ. of Alexandria, Alexandria (Egypt); Poetter Rickard; Kirisits, Christian [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria); Christian Doppler Lab. for Medical Radiation Research for Radiation Oncology, Medical Univ. Vienna (Austria); Berger, Daniel; Federico, Mario; Sturdza, Alina; Nesvacil, Nicole [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria)], e-mail: nicole.nesvacil@meduniwien.ac.at

2013-10-15

Purpose: The aim of the study was to improve computed tomography (CT)-based high-risk clinical target volume (HR CTV) delineation protocols for cervix cancer patients, in settings without any access to magnetic resonance imaging (MRI) at the time of brachytherapy. Therefore the value of a systematic integration of comprehensive three-dimensional (3D) documentation of repetitive gynecological examination for CT-based HR CTV delineation protocols, in addition to information from FIGO staging, was investigated. In addition to a comparison between reference MRI contours and two different CT-based contouring methods (using complementary information from FIGO staging with or without additional 3D clinical drawings), the use of standardized uterine heights was also investigated. Material and methods: Thirty-five cervix cancer patients with CT- and MR-images and 3D clinical drawings at time of diagnosis and brachytherapy were included. HR CTV{sub stage} was based on CT information and FIGO stage. HR CTV{sub stage} {sub +3Dclin} was contoured on CT using FIGO stage and 3D clinical drawing. Standardized HR CTV heights were: 1/1, 2/3 and 1/2 of uterine height. MRI-based HR CTV was delineated independently. Resulting widths, thicknesses, heights, and volumes of HR CTV{sub stage}, HR CTV{sub stage+3Dclin} and MRI-based HR CTV contours were compared. Results: The overall normalized volume ratios (mean{+-}SD of CT/MRI{sub ref} volume) of HR CTV{sub stage} and HR{sub stage+3Dclin} were 2.6 ({+-}0.6) and 2.1 ({+-}0.4) for 1/1 and 2.3 ({+-}0.5) and 1.8 ({+-}0.4), for 2/3, and 1.9 ({+-}0.5) and 1.5 ({+-}0.3), for 1/2 of uterine height. The mean normalized widths were 1.5{+-}0.2 and 1.2{+-}0.2 for HR CTV{sub stage} and HR CTV{sub stage+3Dclin}, respectively (p < 0.05). The mean normalized heights for HR CTV{sub stage} and HR CTV{sub stage+3Dclin} were both 1.7{+-}0.4 for 1/1 (p < 0.05.), 1.3{+-}0.3 for 2/3 (p < 0.05) and 1.1{+-}0.3 for 1/2 of uterine height. Conclusion: CT-based HR

Feasibility of sentinel node lymphoscintigraphy in stage I testicular cancer

Energy Technology Data Exchange (ETDEWEB)

Tanis, Pieter J.; Nieweg, Omgo E. [Department of Surgery, Netherlands Cancer Institute, Amsterdam (Netherlands); Horenblas, Simon [Department of Urology, Netherlands Cancer Institute, Amsterdam (Netherlands); Olmos, Renato Valdes A.; Hoefnagel, Cornelis A. [Department of Nuclear Medicine, The Netherlands Cancer Institute, Amsterdam (Netherlands)

2002-05-01

The aim of this study was to investigate the feasibility of lymphoscintigraphy for sentinel node identification in testicular cancer. Five patients with clinical stage I testicular cancer were prospectively included. A single dose of technetium-99m nanocolloid (mean dose 99 MBq, volume 0.2 ml) was injected into the funiculus in the first patient and into the testicular parenchyma in the following four patients. Dynamic lymphoscintigraphy was performed over 10 min, followed by early and late static images after 15 min and 2 to 24 h, respectively. Lymphoscintigraphy was followed by laparoscopic sentinel node biopsy on the same day in the last two patients using patent blue dye and an endoscopic gamma probe. The funicular administration route showed five hot spots in the right inguinal region after 2 h. Intratesticular administration resulted in sentinel node visualisation in three of the four patients. Dynamic images showed afferent lymphatic vessels to one sentinel node in the left para-aortic region in two patients and two sentinel nodes in the left para-aortic region in another patient. Sentinel nodes were intraoperatively identified in one of two patients who underwent laparoscopic exploration. It is concluded that lymphoscintigraphy for sentinel node identification is feasible in stage I testicular cancer using intratesticular radiocolloid administration. (orig.)

Chronic infections in hip arthroplasties: comparing risk of reinfection following one-stage and two-stage revision: a systematic review and meta-analysis

Directory of Open Access Journals (Sweden)

Lange J

2012-03-01

Full Text Available Jeppe Lange1,2, Anders Troelsen3, Reimar W Thomsen4, Kjeld Søballe1,51Lundbeck Foundation Centre for Fast-Track Hip and Knee Surgery, Aarhus C, 2Center for Planned Surgery, Silkeborg Regional Hospital, Silkeborg, 3Department of Orthopaedics, Hvidovre Hospital, Hvidovre, 4Department of Clinical Epidemiology, Aarhus University Hospital, Aalborg, 5Department of Orthopaedics, Aarhus University Hospital, Aarhus C, DenmarkBackground: Two-stage revision is regarded by many as the best treatment of chronic infection in hip arthroplasties. Some international reports, however, have advocated one-stage revision. No systematic review or meta-analysis has ever compared the risk of reinfection following one-stage and two-stage revisions for chronic infection in hip arthroplasties.Methods: The review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Relevant studies were identified using PubMed and Embase. We assessed studies that included patients with a chronic infection of a hip arthroplasty treated with either one-stage or two-stage revision and with available data on occurrence of reinfections. We performed a meta-analysis estimating absolute risk of reinfection using a random-effects model.Results: We identified 36 studies eligible for inclusion. None were randomized controlled trials or comparative studies. The patients in these studies had received either one-stage revision (n = 375 or two-stage revision (n = 929. Reinfection occurred with an estimated absolute risk of 13.1% (95% confidence interval: 10.0%–17.1% in the one-stage cohort and 10.4% (95% confidence interval: 8.5%–12.7% in the two-stage cohort. The methodological quality of most included studies was considered low, with insufficient data to evaluate confounding factors.Conclusions: Our results may indicate three additional reinfections per 100 reimplanted patients when performing a one-stage versus two-stage revision. However, the

Hypospadias repair: Byar's two stage operation revisited.

Science.gov (United States)

Arshad, A R

2005-06-01

Hypospadias is a congenital deformity characterised by an abnormally located urethral opening, that could occur anywhere proximal to its normal location on the ventral surface of glans penis to the perineum. Many operations had been described for the management of this deformity. One hundred and fifteen patients with hypospadias were treated at the Department of Plastic Surgery, Hospital Kuala Lumpur, Malaysia between September 1987 and December 2002, of which 100 had Byar's procedure performed on them. The age of the patients ranged from neonates to 26 years old. Sixty-seven patients had penoscrotal (58%), 20 had proximal penile (18%), 13 had distal penile (11%) and 15 had subcoronal hypospadias (13%). Operations performed were Byar's two-staged (100), Bracka's two-staged (11), flip-flap (2) and MAGPI operation (2). The most common complication encountered following hypospadias surgery was urethral fistula at a rate of 18%. There is a higher incidence of proximal hypospadias in the Malaysian community. Byar's procedure is a very versatile technique and can be used for all types of hypospadias. Fistula rate is 18% in this series.

EFFECT OF HARDENING TIME ON DEFORMATION-STRENGTH INDICATORS OF CONCRETE FOR INJECTION WITH A TWO-STAGE EXPANSION DURING HARDENING IN WATER

Directory of Open Access Journals (Sweden)

Tatjana N. Zhilnikova

2017-01-01

Full Text Available Abstract. Objectives Concretes for injection with a two-stage expansion are a kind of selfstressing concrete obtained with the use of self-stressing cement.The aim of the work is to study the influence of the duration of aging on the porosity, strength and self-stress of concrete hardening in water, depending on the expansion value at the first stage. At the first stage, the compacted concrete mixture is expanded to ensure complete filling of the formwork space. At the second stage, the hardening concrete expands due to the formation of an increased amount of ettringite. This process is prolonged in time, with the amount of self-stress and strength dependant on the conditions of hardening. Methods  Experimental evaluation of self-stress, strength and porosity of concretes that are permanently hardened in water, under air-moist and air-dry conditions after different expansion at the first stage. The self-stress of cement stone is the result of superposition of two processes: the hardening of the structure due to hydration of silicates and its expansion as a result of hydration of calcium aluminates with the subsequent formation of ettringite. The magnitude of self-stress is determined by the ratio of these two processes. The self-stress of the cement stone changes in a manner similar to the change in its expansion. The stabilisation of expansion is accompanied by stabilisation of self-stress of cement stone. Results  The relationship of self-stress, strength and porosity of concrete for injection with a two-stage expansion on the duration and humidity conditions of hardening, taking into account the conditions of deformation limitation at the first stage, is revealed. Conclusion During prolonged hardening in an aqueous medium, self-stresses are reduced up to 25% with the exception of expansion at the first stage and up to 20% with an increase in volume up to 5% at the first stage. The increase in compressive strength is up to 28% relative to

Fibrosis-Related Gene Expression in Single Ventricle Heart Disease.

Science.gov (United States)

Nakano, Stephanie J; Siomos, Austine K; Garcia, Anastacia M; Nguyen, Hieu; SooHoo, Megan; Galambos, Csaba; Nunley, Karin; Stauffer, Brian L; Sucharov, Carmen C; Miyamoto, Shelley D

2017-12-01

To evaluate fibrosis and fibrosis-related gene expression in the myocardium of pediatric subjects with single ventricle with right ventricular failure. Real-time quantitative polymerase chain reaction was performed on explanted right ventricular myocardium of pediatric subjects with single ventricle disease and controls with nonfailing heart disease. Subjects were divided into 3 groups: single ventricle failing (right ventricular failure before or after stage I palliation), single ventricle nonfailing (infants listed for primary transplantation with normal right ventricular function), and stage III (Fontan or right ventricular failure after stage III). To evaluate subjects of similar age and right ventricular volume loading, single ventricle disease with failure was compared with single ventricle without failure and stage III was compared with nonfailing right ventricular disease. Histologic fibrosis was assessed in all hearts. Mann-Whitney tests were performed to identify differences in gene expression. Collagen (Col1α, Col3) expression is decreased in single ventricle congenital heart disease with failure compared with nonfailing single ventricle congenital heart disease (P = .019 and P = .035, respectively), and is equivalent in stage III compared with nonfailing right ventricular heart disease. Tissue inhibitors of metalloproteinase (TIMP-1, TIMP-3, and TIMP-4) are downregulated in stage III compared with nonfailing right ventricular heart disease (P = .0047, P = .013 and P = .013, respectively). Matrix metalloproteinases (MMP-2, MMP-9) are similar between nonfailing single ventricular heart disease and failing single ventricular heart disease, and between stage III heart disease and nonfailing right ventricular heart disease. There is no difference in the prevalence of right ventricular fibrosis by histology in subjects with single ventricular failure heart disease with right ventricular failure (18%) compared with those with normal right

A two-stage method for inverse medium scattering

KAUST Repository

Ito, Kazufumi; Jin, Bangti; Zou, Jun

2013-01-01

We present a novel numerical method to the time-harmonic inverse medium scattering problem of recovering the refractive index from noisy near-field scattered data. The approach consists of two stages, one pruning step of detecting the scatterer

Combining evidence from multiple electronic health care databases: performances of one-stage and two-stage meta-analysis in matched case-control studies.

Science.gov (United States)

La Gamba, Fabiola; Corrao, Giovanni; Romio, Silvana; Sturkenboom, Miriam; Trifirò, Gianluca; Schink, Tania; de Ridder, Maria

2017-10-01

Clustering of patients in databases is usually ignored in one-stage meta-analysis of multi-database studies using matched case-control data. The aim of this study was to compare bias and efficiency of such a one-stage meta-analysis with a two-stage meta-analysis. First, we compared the approaches by generating matched case-control data under 5 simulated scenarios, built by varying: (1) the exposure-outcome association; (2) its variability among databases; (3) the confounding strength of one covariate on this association; (4) its variability; and (5) the (heterogeneous) confounding strength of two covariates. Second, we made the same comparison using empirical data from the ARITMO project, a multiple database study investigating the risk of ventricular arrhythmia following the use of medications with arrhythmogenic potential. In our study, we specifically investigated the effect of current use of promethazine. Bias increased for one-stage meta-analysis with increasing (1) between-database variance of exposure effect and (2) heterogeneous confounding generated by two covariates. The efficiency of one-stage meta-analysis was slightly lower than that of two-stage meta-analysis for the majority of investigated scenarios. Based on ARITMO data, there were no evident differences between one-stage (OR = 1.50, CI = [1.08; 2.08]) and two-stage (OR = 1.55, CI = [1.12; 2.16]) approaches. When the effect of interest is heterogeneous, a one-stage meta-analysis ignoring clustering gives biased estimates. Two-stage meta-analysis generates estimates at least as accurate and precise as one-stage meta-analysis. However, in a study using small databases and rare exposures and/or outcomes, a correct one-stage meta-analysis becomes essential. Copyright © 2017 John Wiley & Sons, Ltd.

Current evolutionary stage of L/ILW management at operating NPP in the USA

International Nuclear Information System (INIS)

Miller, C.C.

2001-01-01

The volume of Low and Intermediate Level Waste (L/ILW) from commercial nuclear power plants (NPP) buried annually in the USA has decreased dramatically over the last two decades. The reduction in disposal volume has occurred for both dry active wastes (DAW) and wet wastes (e.g., resins, filters and sludges). Decreased disposal volume has occurred at both Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs). The reduction in disposal volume occurred in stages. The major driver to reduce disposal volume in the commercial sector of the USA has been increasing burial costs. The current drive to further reduce overall NPP operating costs to meet a deregulated electric market in the USA has unexpectedly resulted in further waste reductions. This paper will review the stages of waste reduction and describe the current stage for NPP in the USA. (author)

Effect of two-stage sintering process on microstructure and mechanical properties of ODS tungsten heavy alloy

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyong H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of); Cha, Seung I. [International Center for Young Scientists, National Institute for Materials Science 1-1, Namiki, Tsukuba 305-0044 (Japan); Ryu, Ho J. [DUPIC, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yusong-gu, Taejon 305-353 (Korea, Republic of); Hong, Soon H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of)], E-mail: shhong@kaist.ac.kr

2007-06-15

Oxide dispersion strengthened (ODS) tungsten heavy alloys have been considered as promising candidates for advanced kinetic energy penetrator due to their characteristic fracture mode compared to conventional tungsten heavy alloy. In order to obtain high relative density, the ODS tungsten heavy alloy needs to be sintered at higher temperature for longer time, however, induces growth of tungsten grains. Therefore, it is very difficult to obtain controlled microstructure of ODS tungsten heavy alloy having fine tungsten grains with full densification. In this study, two-stage sintering process, consisted of primary solid-state sintering and followed by secondary liquid phase sintering, was introduced for ODS tungsten heavy alloys. The mechanically alloyed 94W-4.56Ni-1.14Fe-0.3Y{sub 2}O{sub 3} powders are solid-state sintered at 1300-1450 deg. C for 1 h in hydrogen atmosphere, and followed by liquid phase sintering temperature at 1465-1485 deg. C for 0-60 min. The microstructure of ODS tungsten heavy alloys showed high relative density above 97%, with contiguous tungsten grains after primary solid-state sintering. The microstructure of solid-state sintered ODS tungsten heavy alloy was changed into spherical tungsten grains embedded in W-Ni-Fe matrix during secondary liquid phase sintering. The two-stage sintered ODS tungsten heavy alloy from mechanically alloyed powders showed finer microstructure and higher mechanical properties than conventional liquid phase sintered alloy. The mechanical properties of ODS tungsten heavy alloys are dependent on the microstructural parameters such as tungsten grain size, matrix volume fraction and tungsten/tungsten contiguity, which can be controlled through the two-stage sintering process.

Hydrogen production from cellulose in a two-stage process combining fermentation and electrohydrogenesis

KAUST Repository

Lalaurette, Elodie

2009-08-01

A two-stage dark-fermentation and electrohydrogenesis process was used to convert the recalcitrant lignocellulosic materials into hydrogen gas at high yields and rates. Fermentation using Clostridium thermocellum produced 1.67 mol H2/mol-glucose at a rate of 0.25 L H2/L-d with a corn stover lignocellulose feed, and 1.64 mol H2/mol-glucose and 1.65 L H2/L-d with a cellobiose feed. The lignocelluose and cellobiose fermentation effluent consisted primarily of: acetic, lactic, succinic, and formic acids and ethanol. An additional 800 ± 290 mL H2/g-COD was produced from a synthetic effluent with a wastewater inoculum (fermentation effluent inoculum; FEI) by electrohydrogensis using microbial electrolysis cells (MECs). Hydrogen yields were increased to 980 ± 110 mL H2/g-COD with the synthetic effluent by combining in the inoculum samples from multiple microbial fuel cells (MFCs) each pre-acclimated to a single substrate (single substrate inocula; SSI). Hydrogen yields and production rates with SSI and the actual fermentation effluents were 980 ± 110 mL/g-COD and 1.11 ± 0.13 L/L-d (synthetic); 900 ± 140 mL/g-COD and 0.96 ± 0.16 L/L-d (cellobiose); and 750 ± 180 mL/g-COD and 1.00 ± 0.19 L/L-d (lignocellulose). A maximum hydrogen production rate of 1.11 ± 0.13 L H2/L reactor/d was produced with synthetic effluent. Energy efficiencies based on electricity needed for the MEC using SSI were 270 ± 20% for the synthetic effluent, 230 ± 50% for lignocellulose effluent and 220 ± 30% for the cellobiose effluent. COD removals were ∼90% for the synthetic effluents, and 70-85% based on VFA removal (65% COD removal) with the cellobiose and lignocellulose effluent. The overall hydrogen yield was 9.95 mol-H2/mol-glucose for the cellobiose. These results show that pre-acclimation of MFCs to single substrates improves performance with a complex mixture of substrates, and that high hydrogen yields and gas production rates can be achieved using a two-stage fermentation and MEC

FIRST DIRECT EVIDENCE OF TWO STAGES IN FREE RECALL

Directory of Open Access Journals (Sweden)

Eugen Tarnow

2015-12-01

Full Text Available I find that exactly two stages can be seen directly in sequential free recall distributions. These distributions show that the first three recalls come from the emptying of working memory, recalls 6 and above come from a second stage and the 4th and 5th recalls are mixtures of the two.A discontinuity, a rounded step function, is shown to exist in the fitted linear slope of the recall distributions as the recall shifts from the emptying of working memory (positive slope to the second stage (negative slope. The discontinuity leads to a first estimate of the capacity of working memory at 4-4.5 items. The total recall is shown to be a linear combination of the content of working memory and items recalled in the second stage with 3.0-3.9 items coming from working memory, a second estimate of the capacity of working memory. A third, separate upper limit on the capacity of working memory is found (3.06 items, corresponding to the requirement that the content of working memory cannot exceed the total recall, item by item. This third limit is presumably the best limit on the average capacity of unchunked working memory.The second stage of recall is shown to be reactivation: The average times to retrieve additional items in free recall obey a linear relationship as a function of the recall probability which mimics recognition and cued recall, both mechanisms using reactivation (Tarnow, 2008.

Modal intersection types, two-level languages, and staged synthesis

DEFF Research Database (Denmark)

Henglein, Fritz; Rehof, Jakob

2016-01-01

-linguistic framework for staged program synthesis, where metaprograms are automatically synthesized which, when executed, generate code in a target language. We survey the basic theory of staged synthesis and illustrate by example how a two-level language theory specialized from λ∩ ⎕ can be used to understand......A typed λ-calculus, λ∩ ⎕, is introduced, combining intersection types and modal types. We develop the metatheory of λ∩ ⎕, with particular emphasis on the theory of subtyping and distributivity of the modal and intersection type operators. We describe how a stratification of λ∩ ⎕ leads to a multi...... the process of staged synthesis....

Evaluation of single-stage adjustable strabismus surgery under conscious sedation

Directory of Open Access Journals (Sweden)

Sharma Pradeep

2009-01-01

Full Text Available Purpose: To evaluate the feasibility and stability of ocular alignment after single-stage adjustable strabismus surgery (SSASS performed under topical anesthesia. Materials and Methods: Forty-five patients of concomitant exodeviations were randomized into three groups of 15 cases each and were operated with three different techniques: Group I - conventional surgery, Group II - two-stage adjustable suture technique with suture adjustment performed 6h postoperatively and Group III- SSASS under topical anesthesia and intravenous conscious sedation with midazolam and fentanyl. Intraoperative suture adjustment was done by giving a cross target to the patient on the ceiling at the end of the procedure. Surgical results were compared among the three groups at three months follow-up. Intraoperative hemodynamic parameters and patients′ experience of the surgery (by questionnaire were also compared. Results: Mean preoperative deviation for distance in Groups I, II, III was -41.67 prism diopter (pd ±9.0, -38.93 pd ±11.05 and -41.87 pd ±8.91 ( P =0.6 respectively. At three months, mean correction achieved for distance was +31.87 pd ±11.71, +35.47 pd ±10.86 and +42.80 pd ±10.71 respectively which was significantly different between Group III and Group I ( P =0.03. Intraoperatively all hemodynamic parameters remained stable and comparable ( P =0. 5 in all groups. Intraoperative pain ( P < 0.001 and time taken for surgery ( P < 0.001 was more in the SSASS group. Amount of exodrift was 10-12 pd, comparable in all three groups ( P = 0.5. Conclusions: SSASS, performed under topical anesthesia, is safe and has better outcomes than conventional recession-resection surgery for concomitant exodeviation. An overcorrection of about 10-12 pd is recommended to check the exodrift and achieve stable alignment.

Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

International Nuclear Information System (INIS)

Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R.

2014-01-01

High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target

Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

Energy Technology Data Exchange (ETDEWEB)

Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2014-04-28

High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

Empirical study of classification process for two-stage turbo air classifier in series

Science.gov (United States)

Yu, Yuan; Liu, Jiaxiang; Li, Gang

2013-05-01

The suitable process parameters for a two-stage turbo air classifier are important for obtaining the ultrafine powder that has a narrow particle-size distribution, however little has been published internationally on the classification process for the two-stage turbo air classifier in series. The influence of the process parameters of a two-stage turbo air classifier in series on classification performance is empirically studied by using aluminum oxide powders as the experimental material. The experimental results show the following: 1) When the rotor cage rotary speed of the first-stage classifier is increased from 2 300 r/min to 2 500 r/min with a constant rotor cage rotary speed of the second-stage classifier, classification precision is increased from 0.64 to 0.67. However, in this case, the final ultrafine powder yield is decreased from 79% to 74%, which means the classification precision and the final ultrafine powder yield can be regulated through adjusting the rotor cage rotary speed of the first-stage classifier. 2) When the rotor cage rotary speed of the second-stage classifier is increased from 2 500 r/min to 3 100 r/min with a constant rotor cage rotary speed of the first-stage classifier, the cut size is decreased from 13.16 μm to 8.76 μm, which means the cut size of the ultrafine powder can be regulated through adjusting the rotor cage rotary speed of the second-stage classifier. 3) When the feeding speed is increased from 35 kg/h to 50 kg/h, the "fish-hook" effect is strengthened, which makes the ultrafine powder yield decrease. 4) To weaken the "fish-hook" effect, the equalization of the two-stage wind speeds or the combination of a high first-stage wind speed with a low second-stage wind speed should be selected. This empirical study provides a criterion of process parameter configurations for a two-stage or multi-stage classifier in series, which offers a theoretical basis for practical production.

Sourcing for Quality: Cooperating with a Single Supplier or Developing Two Competing Suppliers?

Directory of Open Access Journals (Sweden)

Jingxian Chen

2016-01-01

Full Text Available Supplier efforts regarding product quality are an important issue in outsourcing and play a critical role in a manufacturer’s choice of sourcing strategy. Consider a manufacturer that wants to outsource the manufacturing of two substitute products to external suppliers. This paper studies the strategic interactions under two sourcing strategies: single and dual sourcing. A four-stage noncooperative game model is established to describe each member’s decisions. We further propose four decision scenarios: single sourcing with and without manufacturer quality investment sharing and dual sourcing when suppliers cooperate or do not cooperate on quality decisions. By the backward induction approach, we obtain analytical equilibrium solutions for each decision scenario. By comparing each pair of equilibrium profiles, we find that an appropriate proportion of quality investment sharing by the manufacturer can enable a cooperating strategy with a single supplier to be the dominant strategy. When the manufacturer does not want to share or does not want to share a relatively large portion of its supplier’s quality investment, it will always prefer to develop two competing suppliers when the cost of dual sourcing is sufficiently low. However, dual sourcing can be extremely risky for the manufacturer because the suppliers could provide a relatively low product quality level by cooperating on the quality decision to extract the manufacturer’s profit.

Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP) procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy) for the management of cholelithiasis with choledocholithiasis.

Science.gov (United States)

Sahoo, Manash Ranjan; Kumar, Anil T; Patnaik, Aashish

2014-07-01

The 'Rendezvous' technique consists of laparoscopic cholecystectomy (LC) standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In 'group-A',41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP) and common bile duct (CBD) clearance and second by LC. In 'group-B', 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5%) and in arm-B in 39 cases (93%). In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22%) and severe pancreatitis in five patients (12%) versus none of the patients (0%) in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient's compliance and prevents unnecessary intervention to CBD.

Two-stage gas-phase bioreactor for the combined removal of hydrogen sulphide, methanol and alpha-pinene.

Science.gov (United States)

Rene, Eldon R; Jin, Yaomin; Veiga, María C; Kennes, Christian

2009-11-01

Biological treatment systems have emerged as cost-effective and eco-friendly techniques for treating waste gases from process industries at moderately high gas flow rates and low pollutant concentrations. In this study, we have assessed the performance of a two-stage bioreactor, namely a biotrickling filter packed with pall rings (BTF, 1st stage) and a perlite + pall ring mixed biofilter (BF, 2nd stage) operated in series, for handling a complex mixture of hydrogen sulphide (H2S), methanol (CH3OH) and alpha-pinene (C10H16). It has been reported that the presence of H2S can reduce the biofiltration efficiency of volatile organic compounds (VOCs) when both are present in the gas mixture. Hydrogen sulphide and methanol were removed in the first stage BTF, previously inoculated with H2S-adapted populations and a culture containing Candida boidinii, an acid-tolerant yeast, whereas, in the second stage, alpha-pinene was removed predominantly by the fungus Ophiostoma stenoceras. Experiments were conducted in five different phases, corresponding to inlet loading rates varying between 2.1 and 93.5 g m(-3) h(-1) for H2S, 55.3 and 1260.2 g m(-3) h(-1) for methanol, and 2.8 and 161.1 g m(-3) h(-1) for alpha-pinene. Empty bed residence times were varied between 83.4 and 10 s in the first stage and 146.4 and 17.6 s in the second stage. The BTF, working at a pH as low as 2.7 as a result of H2S degradation, removed most of the H2S and methanol but only very little alpha-pinene. On the other hand, the BF, at a pH around 6.0, removed the rest of the H2S, the non-degraded methanol and most of the alpha-pinene vapours. Attempts were originally made to remove the three pollutants in a single acidophilic bioreactor, but the Ophiostoma strain was hardly active at pH elimination capacities (ECs) reached by the two-stage bioreactor for individual pollutants were 894.4 g m(-3) h(-1) for methanol, 45.1 g m(-3) h(-1) for H2S and 138.1 g m(-3) h(-1) for alpha-pinene. The results from this

Comparison of feature and classifier algorithms for online automatic sleep staging based on a single EEG signal

NARCIS (Netherlands)

Radha, M.; Garcia Molina, G.; Poel, M.; Tononi, G.

2014-01-01

Automatic sleep staging on an online basis has recently emerged as a research topic motivated by fundamental sleep research. The aim of this paper is to find optimal signal processing methods and machine learning algorithms to achieve online sleep staging on the basis of a single EEG signal. The

Two-stage, high power X-band amplifier experiment

International Nuclear Information System (INIS)

Kuang, E.; Davis, T.J.; Ivers, J.D.; Kerslick, G.S.; Nation, J.A.; Schaechter, L.

1993-01-01

At output powers in excess of 100 MW the authors have noted the development of sidebands in many TWT structures. To address this problem an experiment using a narrow bandwidth, two-stage TWT is in progress. The TWT amplifier consists of a dielectric (e = 5) slow-wave structure, a 30 dB sever section and a 8.8-9.0 GHz passband periodic, metallic structure. The electron beam used in this experiment is a 950 kV, 1 kA, 50 ns pencil beam propagating along an applied axial field of 9 kG. The dielectric first stage has a maximum gain of 30 dB measured at 8.87 GHz, with output powers of up to 50 MW in the TM 01 mode. In these experiments the dielectric amplifier output power is about 3-5 MW and the output power of the complete two-stage device is ∼160 MW at the input frequency. The sidebands detected in earlier experiments have been eliminated. The authors also report measurements of the energy spread of the electron beam resulting from the amplification process. These experimental results are compared with MAGIC code simulations and analytic work they have carried out on such devices

Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

Science.gov (United States)

Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

2016-05-15

Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

The resistive plate WELL detector as a single stage thick gaseous multiplier detector

Energy Technology Data Exchange (ETDEWEB)

Bressler, Shikma; Breskin, Amos; Moleri, Luca; Kumar, Ashwini; Pitt, Michael [Department of Particle Physics and Astrophysics, Weizmann Institute of Science (WIS) (Israel); Kudella, Simon [Institut fuer Experimentelle Kernphysik (IEKP), KIT (Germany)

2015-07-01

Gaseous Electron Multiplier (GEM) detector use high electric fields inside the h ole of a foil to achieve a high charge multiplication. As a thicker version of G EMs based on printed circuit board (PCB) structures, Thick Gaseous Electron Multiplier (THGEM) detectors combine the high gain of a GEM foil with the robustness, stability and low production costs of a PCB and allow a large quantity of applications that require the coverage of a large area at low cost and moderate spatial resolution. One application the Weizmann Institute of Science (WIS) develops as a member of the RD51 framework is the Resistive Plate WELL (RPWELL) detector. This single stage detector allows a very stable, discharge free operation at high gain (10{sup 5}). The single stage operation allows a low total height and make s the RPWELL a candidate for the Digital Hadronic Calorimeter (DHCAL) of the International Large Detector (ILD) at the International Linear Collider (ILC). The talk gives an insight into the way the RPWELL works and shows results from the last test beam.

Noncausal two-stage image filtration at presence of observations with anomalous errors

OpenAIRE

S. V. Vishnevyy; S. Ya. Zhuk; A. N. Pavliuchenkova

2013-01-01

Introduction. It is necessary to develop adaptive algorithms, which allow to detect such regions and to apply filter with respective parameters for suppression of anomalous noises for the purposes of image filtration, which consist of regions with anomalous errors. Development of adaptive algorithm for non-causal two-stage images filtration at pres-ence of observations with anomalous errors. The adaptive algorithm for noncausal two-stage filtration is developed. On the first stage the adaptiv...

The impact of MRI sequence on tumour staging and gross tumour volume delineation in squamous cell carcinoma of the anal canal

International Nuclear Information System (INIS)

Prezzi, Davide; Mandegaran, Ramin; Gourtsoyianni, Sofia; Owczarczyk, Katarzyna; Gaya, Andrew; Glynne-Jones, Robert; Goh, Vicky

2018-01-01

To compare maximum tumour diameter (MTD) and gross tumour volume (GTV) measurements between T 2 -weighted (T 2 -w) and diffusion-weighted (DWI) MRI in squamous cell carcinoma of the anal canal (SCCA) and assess sequence impact on tumour (T) staging. Second, to evaluate interobserver agreement and reader delineation confidence. The staging MRI scans of 45 SCCA patients (25 females) were assessed retrospectively by two independent radiologists (0 and 5 years' experience of anal cancer MRI). MTD and GTV were delineated on both T 2 -w and high-b-value DWI images and compared between sequences; T staging was derived from MTD. Interobserver agreement was assessed and delineation confidence scored (1 to 5) by each observer. GTV and MTD were significantly and systematically lower on DWI versus T 2 -w sequences by 14.80%/9.98% (MTD) and 29.70%/12.25% (GTV) for each reader, respectively, causing T staging discordances in approximately a quarter of cases. Bland-Altman limits of agreement were narrower and intraclass correlation coefficients higher for DWI. Delineation confidence was greater on DWI: 40/42 cases were scored confidently (4 or 5) by each reader, respectively, versus 31/36 cases based on T 2 -w images. Sequence selection affects SCCA measurements and T stage. DWI yields higher interobserver agreement and greater tumour delineation confidence. (orig.)

Stage-by-Stage and Parallel Flow Path Compressor Modeling for a Variable Cycle Engine

Science.gov (United States)

Kopasakis, George; Connolly, Joseph W.; Cheng, Larry

2015-01-01

This paper covers the development of stage-by-stage and parallel flow path compressor modeling approaches for a Variable Cycle Engine. The stage-by-stage compressor modeling approach is an extension of a technique for lumped volume dynamics and performance characteristic modeling. It was developed to improve the accuracy of axial compressor dynamics over lumped volume dynamics modeling. The stage-by-stage compressor model presented here is formulated into a parallel flow path model that includes both axial and rotational dynamics. This is done to enable the study of compressor and propulsion system dynamic performance under flow distortion conditions. The approaches utilized here are generic and should be applicable for the modeling of any axial flow compressor design.

Numerical simulations of single and multi-staged injection of H2 in a supersonic scramjet combustor

Directory of Open Access Journals (Sweden)

L. Abu-Farah

2014-12-01

Full Text Available Computational fluid dynamics (CFD simulations of a single staged injection of H2 through a central wedge shaped strut and a multi-staged injection through wall injectors are carried out by using Ansys CFX-12 code. Unstructured tetrahedral grids for narrow channel and quarter geometries of the combustor are generated by using ICEM CFD. Steady three-dimensional (3D Reynolds-averaged Navier-stokes (RANS simulations are carried out in the case of no H2 injection and compared with the simulations of single staged pilot and/or main H2 injections and multistage injection. Shear stress transport (SST based on k-ω turbulent model is adopted. Flow field visualization (complex shock waves interactions and static pressure distribution along the wall of the combustor are predicted and compared with the experimental schlieren images and measured wall static pressures for validation. A good agreement is found between the CFD predicted results and the measured data. The narrow and quarter geometries of the combustor give similar results with very small differences. Multi-staged injections of H2 enhance the turbulent H2/air mixing by forming vortices and additional shock waves (bow shocks.

Radial compressor for a two-stage heat pump. Phase 2; Compresseur radial pour pompe a chaleur bi-etagee. Phase 2

Energy Technology Data Exchange (ETDEWEB)

Schiffmann, J.; Favrat, D. [Federal Institute of Technology (EPFL), Industrial Energy Systems Laboratory (LENI), Lausanne (Switzerland); Molyneaux, A. [Ofttech SA, Lausanne (Switzerland)

2005-07-01

This final report for the Swiss Federal Office of Energy (SFOE) reviews the results of the second phase of a project carried out at the Federal Institute of Technology in Lausanne, Switzerland, that involved the development of a two-stage heat pump that could replace conventional sources of domestic heating such as oil or gas-fired boilers. This report deals with the construction of a single-stage system to test the basic functions, aerodynamic bearings, drive and compressor and thus prove the correctness of the concept of the system. The results of the tests made are presented and discussed.

Multi stage electrodialysis for separation of two metal ion species

Energy Technology Data Exchange (ETDEWEB)

Takahashi, K.; Sakurai, H.; Nii, S.; Sugiura, K. [Nagoya Univ., Nagoya (Japan)

1995-04-20

In this article, separation of two metal ions by electrodialysis with a cation exchange membrane has been investigated. In other words, separation of potassium ion and sodium ion has been investigated by using batch dialysis with and without an electric field and continuous electrodialysis with a four-stage dialyzer. As a result, the difference in the permselectivity between the dialysis with and without an electric field has not been appreciable for the system of potassium and sodium ions with the cation exchange membrane. Concerning the continuous electrodialysis, the concentration ratio between potassium and sodium ions in the outlet solution from the recovery side of the dialyzer has increased with the reflux flow rate and the number of stages. In case when the reflux flow rate has been zero, the concentration ratio with the four-stage dialyzer has become 1.5 which is almost the same as with that with a two-stage dialyzer consisting of a simple membrane. When the reflux flow ratio has been 0.7, the concentration ratio has reached 3.6. 20 refs., 8 figs.

Saha equation, single and two particle states

International Nuclear Information System (INIS)

Kraeft, W.D.; Girardeau, M.D.; Strege, B.

1990-01-01

Single and two particle porperties in dense plasma are discussed in connection with their role in the mass action law for a partially ionized plasma. The two particle bound states are nearly density independent, while the continuum is essentially shifted. The single particle states are damped, and their energy has a negative shift and a parabolic behaviour for small momenta. (orig.)

Hybrid biogas upgrading in a two-stage thermophilic reactor

DEFF Research Database (Denmark)

Corbellini, Viola; Kougias, Panagiotis; Treu, Laura

2018-01-01

The aim of this study is to propose a hybrid biogas upgrading configuration composed of two-stage thermophilic reactors. Hydrogen is directly injected in the first stage reactor. The output gas from the first reactor (in-situ biogas upgrade) is subsequently transferred to a second upflow reactor...... (ex-situ upgrade), in which enriched hydrogenotrophic culture is responsible for the hydrogenation of carbon dioxide to methane. The overall objective of the work was to perform an initial methane enrichment in the in-situ reactor, avoiding deterioration of the process due to elevated pH levels......, and subsequently, to complete the biogas upgrading process in the ex-situ chamber. The methane content in the first stage reactor reached on average 87% and the corresponding value in the second stage was 91%, with a maximum of 95%. A remarkable accumulation of volatile fatty acids was observed in the first...

Runway Operations Planning: A Two-Stage Solution Methodology

Science.gov (United States)

Anagnostakis, Ioannis; Clarke, John-Paul

2003-01-01

The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. Thus, Runway Operations Planning (ROP) is a critical component of airport operations planning in general and surface operations planning in particular. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, may be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. Generating optimal runway operations plans was approached in with a 'one-stage' optimization routine that considered all the desired objectives and constraints, and the characteristics of each aircraft (weight class, destination, Air Traffic Control (ATC) constraints) at the same time. Since, however, at any given point in time, there is less uncertainty in the predicted demand for departure resources in terms of weight class than in terms of specific aircraft, the ROP problem can be parsed into two stages. In the context of the Departure Planner (OP) research project, this paper introduces Runway Operations Planning (ROP) as part of the wider Surface Operations Optimization (SOO) and describes a proposed 'two stage' heuristic algorithm for solving the Runway Operations Planning (ROP) problem. Focus is specifically given on including runway crossings in the planning process of runway operations. In the first stage, sequences of departure class slots and runwy crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the

Determination of adrenal volume by MRI in healthy children

DEFF Research Database (Denmark)

Mouritsen, Annette; Johansen, Marie Lindhardt; Wohlfahrt-Veje, Christine

2014-01-01

, to estimate adrenal size in healthy children and to evaluate determinants of adrenal volume such as age, gender, body size, pubic hair stage and serum levels of adrenal androgens. DESIGN: Two hundred and thirty-five healthy children (116 girls and 119 boys) (age range 10.0-14.8 years) were examined by MRI......% of healthy children aged 10-15 years. Adrenal volume increased with age and Tanner stage of pubic hair. Future studies will unravel whether adrenal MRI is useful when evaluating children with adrenal diseases....... (estimate B = 0.34 ml/year, P = 0.03), age (estimate B = 0.05 ml/year, P = 0.021) and pubic hair stage (estimate B = 0.05 ml/stage, P = 0.075). No associations between adrenal size and serum levels of adrenal androgens were observed. CONCLUSION: It was possible to determine adrenal volume by MRI in only 50...

A dual-stage sodium thermal electrochemical converter (Na-TEC)

Science.gov (United States)

Limia, Alexander; Ha, Jong Min; Kottke, Peter; Gunawan, Andrey; Fedorov, Andrei G.; Lee, Seung Woo; Yee, Shannon K.

2017-12-01

The sodium thermal electrochemical converter (Na-TEC) is a heat engine that generates electricity through the isothermal expansion of sodium ions. The Na-TEC is a closed system that can theoretically achieve conversion efficiencies above 45% when operating between thermal reservoirs at 1150 K and 550 K. However, thermal designs have confined previous single-stage devices to thermal efficiencies below 20%. To mitigate some of these limitations, we consider dividing the isothermal expansion into two stages; one at the evaporator temperature (1150 K) and another at an intermediate temperature (650 K-1050 K). This dual-stage Na-TEC takes advantage of regeneration and reheating, and could be amenable to better thermal management. Herein, we demonstrate how the dual-stage device can improve the efficiency by up to 8% points over the best performing single-stage device. We also establish an application regime map for the single- and dual-stage Na-TEC in terms of the power density and the total thermal parasitic loss. Generally, a single-stage Na-TEC should be used for applications requiring high power densities, whereas a dual-stage Na-TEC should be used for applications requiring high efficiency.

Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

DEFF Research Database (Denmark)

Domingo Felez, Carlos; Mutlu, A. Gizem; Jensen, Marlene Mark

2014-01-01

Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single...... was noted when the duration of aeration was increased while decreasing air flow rate (10.9 +/- 3.2% Delta N2O/Delta TN). The extant ammonium oxidation activity (mgNH(4)(+)-N/gVSS.min) positively correlated with the specific N2O production rate (mgN(2)O-N/gVSS.min) of the systems. Operating under conditions......-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75g-N/L.d) and high nitrogen removal efficiencies (83 +/- 5 and 88 +/- 2%) obtained. Dynamics of liquid phase nitrous (N2O...

Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy for the management of cholelithiasis with choledocholithiasis

Directory of Open Access Journals (Sweden)

Manash Ranjan Sahoo

2014-01-01

Full Text Available Introduction : The ′Rendezvous′ technique consists of laparoscopic cholecystectomy (LC standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. Materials And Methods: From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In ′group-A′,41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP and common bile duct (CBD clearance and second by LC. In ′group-B′, 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. Results: In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5% and in arm-B in 39 cases (93%. In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22% and severe pancreatitis in five patients (12% versus none of the patients (0% in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. Conclusion: One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient′s compliance and prevents unnecessary intervention to CBD.

Sensorless Reserved Power Control Strategy for Two-Stage Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

Due to still increasing penetration level of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A reserved power control, where the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the reserved power control for grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... to achieve the power reserve. In this method, the irradiance measurements that have been used in conventional control schemes to estimate the available PV power are not required, and thereby being a sensorless solution. Simulations and experimental tests have been performed on a 3-kW two-stage single...

Two-Stage orders sequencing system for mixed-model assembly

Science.gov (United States)

Zemczak, M.; Skolud, B.; Krenczyk, D.

2015-11-01

In the paper, the authors focus on the NP-hard problem of orders sequencing, formulated similarly to Car Sequencing Problem (CSP). The object of the research is the assembly line in an automotive industry company, on which few different models of products, each in a certain number of versions, are assembled on the shared resources, set in a line. Such production type is usually determined as a mixed-model production, and arose from the necessity of manufacturing customized products on the basis of very specific orders from single clients. The producers are nowadays obliged to provide each client the possibility to determine a huge amount of the features of the product they are willing to buy, as the competition in the automotive market is large. Due to the previously mentioned nature of the problem (NP-hard), in the given time period only satisfactory solutions are sought, as the optimal solution method has not yet been found. Most of the researchers that implemented inaccurate methods (e.g. evolutionary algorithms) to solving sequencing problems dropped the research after testing phase, as they were not able to obtain reproducible results, and met problems while determining the quality of the received solutions. Therefore a new approach to solving the problem, presented in this paper as a sequencing system is being developed. The sequencing system consists of a set of determined rules, implemented into computer environment. The system itself works in two stages. First of them is connected with the determination of a place in the storage buffer to which certain production orders should be sent. In the second stage of functioning, precise sets of sequences are determined and evaluated for certain parts of the storage buffer under certain criteria.

TWO-STAGE HEAT PUMPS FOR ENERGY SAVING TECHNOLOGIES

Directory of Open Access Journals (Sweden)

A. E. Denysova

2017-09-01

Full Text Available The problem of energy saving becomes one of the most important in power engineering. It is caused by exhaustion of world reserves in hydrocarbon fuel, such as gas, oil and coal representing sources of traditional heat supply. Conventional sources have essential shortcomings: low power, ecological and economic efficiencies, that can be eliminated by using alternative methods of power supply, like the considered one: low-temperature natural heat of ground waters of on the basis of heat pump installations application. The heat supply system considered provides an effective use of two stages heat pump installation operating as heat source at ground waters during the lowest ambient temperature period. Proposed is a calculation method of heat pump installations on the basis of groundwater energy. Calculated are the values of electric energy consumption by the compressors’ drive, and the heat supply system transformation coefficient µ for a low-potential source of heat from ground waters allowing to estimate high efficiency of two stages heat pump installations.

Single stage three level grid interactive MPPT inverter for PV systems

International Nuclear Information System (INIS)

Ozdemir, Saban; Altin, Necmi; Sefa, Ibrahim

2014-01-01

Highlights: • A three phase three-level NPC inverter for grid interactive PV systems is proposed. • A novel MPPT algorithm is introduced for single stage systems. • The proposed algorithm is robust with respect to parameter variations of PV system. • THD level is measured as 3.45% and it meets the international standards (<5%). • Total system efficiency is measured as 93.08%. - Abstract: In this study, three-phase, single stage neutral point clamped grid interactive inverter is designed and implemented. The reference current of the voltage source inverter is determined by maximum power point tracking sub-program in order to obtain maximum power from photovoltaic modules instantaneously. Proposed control is realized via TMS320F28335 32-bit floating point processor. The modified incremental conductance method is applied for maximum power point tracking; the PI regulator is used to control the inverter output current shape and level. Galvanic isolation is provided by a line frequency transformer that matches inverter output voltage to the grid voltage level and prevents DC current injection into the grid. Experimental results show that the designed inverter imports energy to the grid with unity power factor, total harmonic distortion level is 3.45% and this value is in the limits of the international standards. In addition, the total efficiency of the system is measured as 93.08%. The proposed system gets the maximum power from photovoltaic module and dispatches into the grid without using additional DC/DC converter

Propulsion requirements for reusable single-stage-to-orbit rocket vehicles

Science.gov (United States)

Stanley, Douglas O.; Engelund, Walter C.; Lepsch, Roger

1994-05-01

The conceptual design of a single-stage-to-orbit (SSTO) vehicle using a wide variety of evolutionary technologies has recently been completed as a part of NASA's Advanced Manned Launch System (AMLS) study. The employment of new propulsion system technologies is critical to the design of a reasonably sized, operationally efficient SSTO vehicle. This paper presents the propulsion system requirements identified for this near-term AMLS SSTO vehicle. Sensitivities of the vehicle to changes in specific impulse and sea-level thrust-to-weight ratio are examined. The results of a variety of vehicle/propulsion system trades performed on the near-term AMLS SSTO vehicle are also presented.

Production of poly-beta-hydroxybutyric acid by microorganisms accumulated from river water using a two-stage perfusion culture system.

Science.gov (United States)

Morimoto, T; Tashiro, F; Nagashima, H; Nishizawa, K; Nagata, F; Yokogawa, Y; Suzuki, T

2000-01-01

The perfusion culture system using a shaken ceramic membrane flask (SCMF) was employed to accumulate microorganisms separated from river water and to produce poly-beta-hydroxybutyric acid (PHB). Using a two-step culture method with a single SCMF, river microorganisms were cultured by separately feeding four representative carbon sources, n-propanol, lactic acid, methanol, and formic acid. After 140 h culture, the cell concentration and PHB content respectively reached 43 g/l and 35% when a propanol medium was fed. Using a two-stage perfusion culture with twin SCMFs, the seed cell mass was increased in the first SCMF and then supplied to the second flask for PHB production. As a consequence, the cellular PHB content rose to 51% in the second SCMF, while the cell concentration gradually increased to 25 g/l after 175 h perfusion culture. These results demonstrated the utility of the two-stage perfusion culture system for developing a cheap means of producing PHB coincident with wastewater treatment.

Predictive and prognostic value of tumor volume and its changes during radical radiotherapy of stage III non-small cell lung cancer. A systematic review

International Nuclear Information System (INIS)

Kaesmann, Lukas; Niyazi, Maximilian; Fleischmann, Daniel; Blanck, Oliver; Baumann, Rene; Baues, Christian; Klook, Lisa; Rosenbrock, Johannes; Trommer-Nestler, Maike; Dobiasch, Sophie; Eze, Chukwuka; Gauer, Tobias; Goy, Yvonne; Giordano, Frank A.; Sautter, Lisa; Hausmann, Jan; Henkenberens, Christoph; Kaul, David; Thieme, Alexander H.; Krug, David; Schmitt, Daniela; Maeurer, Matthias; Panje, Cedric M.; Suess, Christoph; Ziegler, Sonia; Ebert, Nadja; Medenwald, Daniel; Ostheimer, Christian

2018-01-01

Lung cancer remains the leading cause of cancer-related mortality worldwide. Stage III non-small cell lung cancer (NSCLC) includes heterogeneous presentation of the disease including lymph node involvement and large tumour volumes with infiltration of the mediastinum, heart or spine. In the treatment of stage III NSCLC an interdisciplinary approach including radiotherapy is considered standard of care with acceptable toxicity and improved clinical outcome concerning local control. Furthermore, gross tumour volume (GTV) changes during definitive radiotherapy would allow for adaptive replanning which offers normal tissue sparing and dose escalation. A literature review was conducted to describe the predictive value of GTV changes during definitive radiotherapy especially focussing on overall survival. The literature search was conducted in a two-step review process using PubMed registered /Medline registered with the key words ''stage III non-small cell lung cancer'' and ''radiotherapy'' and ''tumour volume'' and ''prognostic factors''. After final consideration 17, 14 and 9 studies with a total of 2516, 784 and 639 patients on predictive impact of GTV, GTV changes and its impact on overall survival, respectively, for definitive radiotherapy for stage III NSCLC were included in this review. Initial GTV is an important prognostic factor for overall survival in several studies, but the time of evaluation and the value of histology need to be further investigated. GTV changes during RT differ widely, optimal timing for re-evaluation of GTV and their predictive value for prognosis needs to be clarified. The prognostic value of GTV changes is unclear due to varying study qualities, re-evaluation time and conflicting results. The main findings were that the clinical impact of GTV changes during definitive radiotherapy is still unclear due to heterogeneous study designs with varying quality

Dentoalveolar growth of patients with complete unilateral cleft lip and palate by early two-stage furlow and push-back method: preliminary results.

Science.gov (United States)

Kitagawa, Taiji; Kohara, Hiroshi; Sohmura, Taiji; Takahashi, Junzo; Tachimura, Takashi; Wada, Takeshi; Kogo, Mikihiko

2004-09-01

This study examined dentoalveolar growth changes prior to the time of palatoplasty up to 3 years of age by the early two-stage Furlow and push-back methods. Thirty-four Japanese patients with complete unilateral cleft lip and palate (UCLP) treated with either a two-stage Furlow procedure (Furlow group: seven boys, eight girls) from 1998 to 2002 or a push-back procedure (push-back group; 12 boys, 7 girls) from 1993 to 1997. Consecutive plaster models were measured by three-dimensional laser scanner, before primary palatoplasty, before hard palate closure (Furlow group only), and at 3 years of age. Bite measures were taken at 3 years of age. In the Furlow group, arch length, canine width, first and second deciduous molar width and cross-sectional area, and depth and volume at midpoint showed greater growth than in the push-back group. In the Furlow group, the crossbite score was also better than in the push-back group at 3 years of age. In comparison with the push-back group, inhibition of growth impediment in the anterior region was observed in the horizontal direction in the Furlow group. In the midregion, it was observed in the horizontal and vertical directions, and in the posterior region it was observed in the horizontal direction. The results demonstrate that the early two-stage Furlow method showed progressive alveolar growth. Therefore, the early two-stage Furlow method is a more beneficial procedure than the push-back method.

Single Stage Contactor Testing Of The Next Generation Solvent Blend

Energy Technology Data Exchange (ETDEWEB)

Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

2014-01-06

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

Development of Explosive Ripper with Two-Stage Combustion

Science.gov (United States)

1974-10-01

inch pipe duct work, the width of this duct proved to be detrimental in marginally rippable material; the duct, instead of the penetrator tip, was...marginally rippable rock. ID. Operating Requirements 2. Fuel The two-stage combustion device is designed to operate using S A 42. the same diesel

Single-stage Kanban system with deterioration failures and condition-based preventive maintenance

International Nuclear Information System (INIS)

Xanthopoulos, A.S.; Koulouriotis, D.E.; Botsaris, P.N.

2015-01-01

Despite the fact that the fields of pull type production control policies and condition-based preventive maintenance have much in common contextually, they have evolved independently up to now. In this investigation, an attempt is made to bridge the gap between these two branches of knowledge by introducing the single-stage Kanban system with deterioration failures and condition-based preventive maintenance. The formalism of continuous time Markov chains is used to model the system and expressions for eight performance metrics are derived. Two important, from a managerial perspective, constrained optimization problems for the proposed model are defined where the objective is the simultaneous optimization of the Kanban policy, the preventive maintenance policy and the inspection schedule under conflicting performance criteria. Multiple instances of each optimization problem are solved by means of the augmented Lagrangian genetic algorithm. The results from the optimization trials coupled by the results from extensive numerical examples facilitate the thorough investigation of the system’s behaviour. - Highlights: • Kanban system with deterioration failures and preventive maintenance is introduced. • The system is modeled as a continuous time Markov chain. • Expressions for eight performance metrics are derived. • The behavior of the system is studied through numerical examples. • Optimization results for selected performance metrics are presented

Emotional And Behavioral Problems of Single Parent Vs. Two Parent Children: Imam Khomeini Charity

Directory of Open Access Journals (Sweden)

A Hajebi

2008-06-01

Full Text Available Background: The aim of this survey is to compare the emotional and behavioral problems of children with only one parent versus those from two-parent families. We analyzed behavioral problems such as aggression, delinquency and socialization issues, as well as emotional problems such as depression, anxiety, and somatic complaints.Methods: Using a multi-stage cluster sampling, 10 of the 20 geographic regions covered by Imam Khomeini Charity were selected. Using systematic random sampling, 460 families with children aged 4-18 years were selected. All children were evaluated using the Child Behavior Check List (CBCL to determine behavioral and emotional problems. Logistic regression tests were conducted to measure the effects variables, including age, gender, number of parents in the family, psychiatric history of each child and history of parental psychiatric treatment, on the internalizing, externalizing and total CBCL scores. A cut-off score of 64 was used to convert raw scores.Results: No differences were observed in CBCL subscales between single-parent children vs. children of two-parent families.Conclusion: Regarding the two-parent families among the study population, the results could not be generalized. As these families have qualified for assistance, the father cannot manage the family because of his disability, such as physical or mental problems. This minimizes the effect of having a father in a two-parent family, rendering them similar to single-parent families. Thus, differences were not observed between the two types of families. Further studies are necessary to compare single-parent families with two-parent families among the community.

Single Ion transient-IBIC analyses of semiconductor devices using a cryogenic temperature stage

International Nuclear Information System (INIS)

Laird, J.S.; Bardos, R.; Legge, G.J.F.; Jagadish, C.

1998-01-01

A new Transient - IBIC data acquisition and analysis system at MARC is described. A discussion on the need for single ion control and temperature control is also given. The recorded signal is used as the trigger for beam pulsing. The new cryostatic temperature control stage is introduced. Data is presented on line profiles across the edge of a Au-Si junction collected over the temperature range of 25-300K using a developed C-V and I-V variable temperature stage incorporating a liquid helium cryostat. It demonstrates the potential improvements in spatial resolution in materials of long lifetime by mapping on timing windows around the prompt charge component in the charge transient

Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

Kinetics analysis of two-stage austenitization in supermartensitic stainless steel

DEFF Research Database (Denmark)

Nießen, Frank; Villa, Matteo; Hald, John

2017-01-01

The martensite-to-austenite transformation in X4CrNiMo16-5-1 supermartensitic stainless steel was followed in-situ during isochronal heating at 2, 6 and 18 K min−1 applying energy-dispersive synchrotron X-ray diffraction at the BESSY II facility. Austenitization occurred in two stages, separated...... that the austenitization kinetics is governed by Ni-diffusion and that slow transformation kinetics separating the two stages is caused by soft impingement in the martensite phase. Increasing the lath width in the kinetics model had a similar effect on the austenitization kinetics as increasing the heating-rate....

Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

Energy Technology Data Exchange (ETDEWEB)

Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong [Inha Univ., Incheon (Korea, Republic of)

2017-01-15

In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

International Nuclear Information System (INIS)

Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong

2017-01-01

In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

Two-Stage Electricity Demand Modeling Using Machine Learning Algorithms

Directory of Open Access Journals (Sweden)

Krzysztof Gajowniczek

2017-10-01

Full Text Available Forecasting of electricity demand has become one of the most important areas of research in the electric power industry, as it is a critical component of cost-efficient power system management and planning. In this context, accurate and robust load forecasting is supposed to play a key role in reducing generation costs, and deals with the reliability of the power system. However, due to demand peaks in the power system, forecasts are inaccurate and prone to high numbers of errors. In this paper, our contributions comprise a proposed data-mining scheme for demand modeling through peak detection, as well as the use of this information to feed the forecasting system. For this purpose, we have taken a different approach from that of time series forecasting, representing it as a two-stage pattern recognition problem. We have developed a peak classification model followed by a forecasting model to estimate an aggregated demand volume. We have utilized a set of machine learning algorithms to benefit from both accurate detection of the peaks and precise forecasts, as applied to the Polish power system. The key finding is that the algorithms can detect 96.3% of electricity peaks (load value equal to or above the 99th percentile of the load distribution and deliver accurate forecasts, with mean absolute percentage error (MAPE of 3.10% and resistant mean absolute percentage error (r-MAPE of 2.70% for the 24 h forecasting horizon.

Single-stage-to-orbit: Meeting the challenge

Science.gov (United States)

Freeman, Delma C., Jr.; Talay, Theodore A.; Austin, Robert Eugene

1995-10-01

There has been and continues to be significant discussion about the viability of fully reusable, single-stage-to-orbit (SSTO) concepts for delivery of payloads to orbit. Often, these discussions have focused in detail on performance and technology requirements relating to the technical feasibility of the concept, with only broad generalizations on how the SSTO will achieve its economic goals of greatly reduced vehicle ground and flight operations costs. With the current industry and NASA Reusable Launch Vehicle Technology Program efforts underway to mature and demonstrate technologies leading to a viable commercial launch system that also satisfies national needs, achieving acceptable recurring costs becomes a significant challenge. This paper reviews the current status of the Reusable Launch Vehicle Technology Program including the DC-XA, X-33, and X-34 flight systems and associated technology programs. The paper also examines lessons learned from the recently completed DC-X reusable rocket demonstrator program. It examines how these technologies and flight systems address the technical and operability challenges of SSTO whose solutions are necessary to reduce costs. The paper also discusses the management and operational approaches that address the challenge of a new cost-effective, reusable launch vehicle system.

An adaptive two-stage dose-response design method for establishing proof of concept.

Science.gov (United States)

Franchetti, Yoko; Anderson, Stewart J; Sampson, Allan R

2013-01-01

We propose an adaptive two-stage dose-response design where a prespecified adaptation rule is used to add and/or drop treatment arms between the stages. We extend the multiple comparison procedures-modeling (MCP-Mod) approach into a two-stage design. In each stage, we use the same set of candidate dose-response models and test for a dose-response relationship or proof of concept (PoC) via model-associated statistics. The stage-wise test results are then combined to establish "global" PoC using a conditional error function. Our simulation studies showed good and more robust power in our design method compared to conventional and fixed designs.

Two-staged management for all types of congenital pouch colon

Directory of Open Access Journals (Sweden)

Rajendra K Ghritlaharey

2013-01-01

Full Text Available Background: The aim of this study was to review our experience with two-staged management for all types of congenital pouch colon (CPC. Patients and Methods: This retrospective study included CPC cases that were managed with two-staged procedures in the Department of Paediatric Surgery, over a period of 12 years from 1 January 2000 to 31 December 2011. Results: CPC comprised of 13.71% (97 of 707 of all anorectal malformations (ARM and 28.19% (97 of 344 of high ARM. Eleven CPC cases (all males were managed with two-staged procedures. Distribution of cases (Narsimha Rao et al.′s classification into types I, II, III, and IV were 1, 2, 6, and 2, respectively. Initial operative procedures performed were window colostomy (n = 6, colostomy proximal to pouch (n = 4, and ligation of colovesical fistula and end colostomy (n = 1. As definitive procedures, pouch excision with abdomino-perineal pull through (APPT of colon in eight, and pouch excision with APPT of ileum in three were performed. The mean age at the time of definitive procedures was 15.6 months (ranges from 3 to 53 months and the mean weight was 7.5 kg (ranges from 4 to 11 kg. Good fecal continence was observed in six and fair in two cases in follow-up periods, while three of our cases lost to follow up. There was no mortality following definitive procedures amongst above 11 cases. Conclusions: Two-staged procedures for all types of CPC can also be performed safely with good results. The most important fact that the definitive procedure is being done without protective stoma and therefore, it avoids stoma closure, stoma-related complications, related cost of stoma closure and hospital stay.

A two-stage preventive maintenance optimization model incorporating two-dimensional extended warranty

International Nuclear Information System (INIS)

Su, Chun; Wang, Xiaolin

2016-01-01

In practice, customers can decide whether to buy an extended warranty or not, at the time of item sale or at the end of the basic warranty. In this paper, by taking into account the moments of customers purchasing two-dimensional extended warranty, the optimization of imperfect preventive maintenance for repairable items is investigated from the manufacturer's perspective. A two-dimensional preventive maintenance strategy is proposed, under which the item is preventively maintained according to a specified age interval or usage interval, whichever occurs first. It is highlighted that when the extended warranty is purchased upon the expiration of the basic warranty, the manufacturer faces a two-stage preventive maintenance optimization problem. Moreover, in the second stage, the possibility of reducing the servicing cost over the extended warranty period is explored by classifying customers on the basis of their usage rates and then providing them with customized preventive maintenance programs. Numerical examples show that offering customized preventive maintenance programs can reduce the manufacturer's warranty cost, while a larger saving in warranty cost comes from encouraging customers to buy the extended warranty at the time of item sale. - Highlights: • A two-dimensional PM strategy is investigated. • Imperfect PM strategy is optimized by considering both two-dimensional BW and EW. • Customers are categorized based on their usage rates throughout the BW period. • Servicing cost of the EW is reduced by offering customized PM programs. • Customers buying the EW at the time of sale is preferred for the manufacturer.

Self-Similar Nanocavity Design with Ultrasmall Mode Volume for Single-Photon Nonlinearities

DEFF Research Database (Denmark)

Choi, Hyeongrak; Heuck, Mikkel; Englund, Dirk R.

2017-01-01

We propose a photonic crystal nanocavity design with self-similar electromagnetic boundary conditions, achieving ultrasmall mode volume (V-eff). The electric energy density of a cavity mode can be maximized in the air or dielectric region, depending on the choice of boundary conditions. We illust...... at the single-photon level. These features open new directions in cavity quantum electrodynamics, spectroscopy, and quantum nonlinear optics....

In vivo effect of single oral dose of artemether against early juvenile stages of Schistosoma mansoni Egyptian strain.

Science.gov (United States)

El-Beshbishi, Samar N; Taman, Amira; El-Malky, Mohamed; Azab, Manar S; El-Hawary, Amira K; El-Tantawy, Dina A

2013-10-01

The current treatment and control of schistosomiasis, rely on a single drug, praziquantel, although, it has minor activity against juvenile stages of the parasite. Studies have shown that artemether (ART) exhibits effects against juveniles of Schistosoma mansoni Liberian and Puerto Rican strains, Schistosoma japonicum and Schistosoma haematobium. Aiming to assess the in vivo activity of single oral dose of ART against early juvenile stages of S. mansoni Egyptian strain, this study was established. Mice were treated with ART (400 mg/kg) at two time points evenly spaced over the period of larval development (7 and 21 days post-infection; pi), and a third treatment point (day 49 pi) was included to elucidate when susceptibility decreases. Administration of ART on day 7 pi reduced the total worm burden by 85.94%. The greatest reductions were seen when treatment was given on day 21 pi, with total and female worm burden reductions of 91.52% and 90.57%, respectively, and cessation of oviposition. Similar dose given on day 49 pi reduced total worm burden by 55.17% and female worm burden by 66.51%. Moreover, it induced significant reduction in the tissue egg load and significant alterations in the oogram pattern with decreased immature eggs and increased dead eggs. Antipathological activities were evident in significant reductions in granulomata count and diameter. In conclusion, ART exhibits major in vivo schistosomicidal effects against the early larval migratory stages of S. mansoni Egyptian strain, mainly the 21-day old schistosomula, hence preventing disease progression and morbidity. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluation of left ventricular function and volume with multidetector-row computed tomography. Comparison with electrocardiogram-gated single photon emission computed tomography

International Nuclear Information System (INIS)

Suzuki, Takeya; Yamashina, Shohei; Nanjou, Shuji; Yamazaki, Junichi

2007-01-01

This study compared left ventricular systolic function and volume determined by multidetector-row computed tomography (MDCT) and electrocardiogram-gated single photon emission computed tomography (G-SPECT) Thirty-seven patients with coronary artery disease and non-cardiovascular disease underwent MDCT. In this study, left ventricular ejection fraction (EF), left ventricular end-diastolic volume (EDV) and left ventricular end-systolic volume (ESV) were calculated using only two-phase imaging with MDCT. Left ventricular function and volume were compared using measurements from G-SPECT. We conducted MDCT and G-SPECT virtually simultaneously. Both the EF and ESV evaluated by MDCT closely correlated with G-SPECT (r=0.763, P 65 bpm) during MDCT significantly influenced the difference in EF calculated from MDCT and G-SPECT (P<0.05). Left ventricular function can be measured with MDCT as well as G-SPECT. However, a heart rate over 65 bpm during MDCT negatively affects the EF correlation between MDCT and G-SPECT. (author)

Two-stage agglomeration of fine-grained herbal nettle waste

Science.gov (United States)

Obidziński, Sławomir; Joka, Magdalena; Fijoł, Olga

2017-10-01

This paper compares the densification work necessary for the pressure agglomeration of fine-grained dusty nettle waste, with the densification work involved in two-stage agglomeration of the same material. In the first stage, the material was pre-densified through coating with a binder material in the form of a 5% potato starch solution, and then subjected to pressure agglomeration. A number of tests were conducted to determine the effect of the moisture content in the nettle waste (15, 18 and 21%), as well as the process temperature (50, 70, 90°C) on the values of densification work and the density of the obtained pellets. For pre-densified pellets from a mixture of nettle waste and a starch solution, the conducted tests determined the effect of pellet particle size (1, 2, and 3 mm) and the process temperature (50, 70, 90°C) on the same values. On the basis of the tests, we concluded that the introduction of a binder material and the use of two-stage agglomeration in nettle waste densification resulted in increased densification work (as compared to the densification of nettle waste alone) and increased pellet density.

A Robust High-Performance GPS L1 Receiver with Single-stage Quadrature Redio-Frequency Circuit

Science.gov (United States)

Liu, Jianghua; Xu, Weilin; Wan, Qinq; Liu, Tianci

2018-03-01

A low power current reuse single-stage quadrature raido-frequency part (SQRF) is proposed for GPS L1 receiver in 180nm CMOS process. The proposed circuit consists of LNA, Mixer, QVCO, is called the QLMV cell. A two blocks stacked topology is adopted in this design. The parallel QVCO and mixer placed on the top forms the upper stacked block, and the LNA placed on the bottom forms the other stacked block. The two blocks share the current and achieve low power performance. To improve the stability, a float current source is proposed. The float current isolated the local oscillation signal and the input RF signal, which bring the whole circuit robust high-performance. The result shows conversion gain is 34 dB, noise figure is three dB, the phase noise is -110 dBc/Hz at 1MHz and IIP3 is -20 dBm. The proposed circuit dissipated 1.7mW with 1 V supply voltage.

Two-stage hepatectomy: who will not jump over the second hurdle?

Science.gov (United States)

Turrini, O; Ewald, J; Viret, F; Sarran, A; Goncalves, A; Delpero, J-R

2012-03-01

Two-stage hepatectomy uses compensatory liver regeneration after a first noncurative hepatectomy to enable a second curative resection in patients with bilobar colorectal liver metastasis (CLM). To determine the predictive factors of failure of two-stage hepatectomy. Between 2000 and 2010, 48 patients with irresectable CLM were eligible for two-stage hepatectomy. The planned strategy was a) cleaning of the left hepatic lobe (first hepatectomy), b) right portal vein embolisation and c) right hepatectomy (second hepatectomy). Six patients had occult CLM (n = 5) or extra-hepatic disease (n = 1), which was discovered during the first hepatectomy. Thus, 42 patients completed the first hepatectomy and underwent portal vein embolisation in order to receive the second hepatectomy. Eight patients did not undergo a second hepatectomy due to disease progression. Upon univariate analysis, two factors were identified that precluded patients from having the second hepatectomy: the combined resection of a primary tumour during the first hepatectomy (p = 0.01) and administration of chemotherapy between the two hepatectomies (p = 0.03). An independent association with impairment to perform the two-stage strategy was demonstrated by multivariate analysis for only the combined resection of the primary colorectal cancer during the first hepatectomy (p = 0.04). Due to the small number of patients and the absence of equivalent conclusions in other studies, we cannot recommend performance of an isolated colorectal resection prior to chemotherapy. However, resection of an asymptomatic primary tumour before chemotherapy should not be considered as an outdated procedure. Copyright © 2011 Elsevier Ltd. All rights reserved.

Equivalence of two models in single-phase multicomponent flow simulations

KAUST Repository

Wu, Yuanqing

2016-02-28

In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

Equivalence of two models in single-phase multicomponent flow simulations

KAUST Repository

Wu, Yuanqing; Sun, Shuyu

2016-01-01

In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

Volume reflection and channeling of ultrarelativistic protons in germanium bent single crystals

Directory of Open Access Journals (Sweden)

S. Bellucci

2016-12-01

Full Text Available The paper is devoted to the investigation of volume reflection and channeling processes of ultrarelativistic positive charged particles moving in germanium single crystals. We demonstrate that the choice of atomic potential on the basis of the Hartree-Fock method and the correct choice of the Debye temperature allow us to describe the above mentioned processes in a good agreement with the recent experiments. Moreover, the universal form of equations for volume reflection presented in the paper gives a true description of the process at a wide range of particle energies. Standing on this study we make predictions for the mean angle reflection (as a function of the bending radius of positive and negative particles for germanium (110 and (111 crystallographic planes.

Single-photon two-qubit entangled states: Preparation and measurement

International Nuclear Information System (INIS)

Kim, Yoon-Ho

2003-01-01

We implement experimentally a deterministic method to prepare and measure the so-called single-photon two-qubit entangled states or single-photon Bell states, in which the polarization and the spatial modes of a single photon each represent a quantum bit. All four single-photon Bell states can be easily prepared and measured deterministically using linear optical elements alone. We also discuss how this method can be used for the recently proposed single-photon two-qubit quantum cryptography scheme

NASA Glenn's Single-Stage Axial Compressor Facility Upgraded

Science.gov (United States)

Brokopp, Richard A.

2004-01-01

NASA Glenn Research Center's Single-Stage Axial Compressor Facility was upgraded in fiscal year 2003 to expand and improve its research capabilities for testing high-speed fans and compressors. The old 3000-hp drive motor and gearbox were removed and replaced with a refurbished 7000-hp drive motor and gearbox, with a maximum output speed of 21,240 rpm. The higher horsepower rating permits testing of fans and compressors with higher pressure ratio or higher flow. A new inline torquemeter was installed to provide an alternate measurement of fan and compressor efficiency, along with the standard pressure and temperature measurements. A refurbished compressor bearing housing was also installed with bidirectional rotation capability, so that a variety of existing hardware could be tested. Four new lubrication modules with backup capability were installed for the motor, gearbox, torquemeter, and compressor bearing housing, so that in case the primary pump fails, the backup will prevent damage to the rotating hardware. The combustion air supply line for the facility inlet air system was activated to provide dry air for repeatable inlet conditions. New flow conditioning hardware was installed in the facility inlet plenum tank, which greatly reduced the inlet turbulence. The new inlet can also be easily modified to accommodate 20- or 22-in.-diameter fans and compressors, so a variety of existing hardware from other facilities (such as Glenn's 9- by 15-Foot Low-Speed Wind Tunnel) can be tested in the Single-Stage Axial Compressor Facility. An exhaust line was also installed to provide bleed capability to remove the inlet boundary layer. To improve the operation and control of the facility, a new programmable logic controller (PLC) was installed to upgrade from hardwired relay logic to software logic. The PLC also enabled the usage of human-machine interface software to allow for easier operation of the facility and easier reconfiguration of the facility controls when

Effects of a Single Bout of Resistance Exercise in Different Volumes on Endothelium Adaptations in Healthy Animals

Directory of Open Access Journals (Sweden)

Marcelo Mendonça Mota

Full Text Available Abstract Background: Resistance exercise (RE has been recommended for patients with cardiovascular diseases. Recently, a few studies have demonstrated that the intensity of a single bout of RE has an effect on endothelial adaptations to exercise. However, there is no data about the effects of different volumes of RE on endothelium function. Objective: The aim of the study was to evaluate the effects of different volumes of RE in a single bout on endothelium-dependent vasodilatation and nitric oxide (NO synthesis in the mesenteric artery of healthy animals. Methods: Male Wistar rats were divided into three groups: Control (Ct; low-volume RE (LV, 5 sets x 10 repetitions and high-volume RE (HV, 15 sets x 10 repetitions. The established intensity was 70% of the maximal repetition test. After the exercise protocol, rings of mesenteric artery were used for assessment of vascular reactivity, and other mesenteric arteries were prepared for detection of measure NO production by DAF-FM fluorescence. Insulin responsiveness on NO synthesis was evaluated by stimulating the vascular rings with insulin (10 nM. Results: The maximal relaxation response to insulin increased in the HV group only as compared with the Ct group. Moreover, the inhibition of nitric oxide synthesis (L-NAME completely abolished the insulin-induced vasorelaxation in exercised rats. NO production showed a volume-dependent increase in the endothelial and smooth muscle layer. In endothelial layer, only Ct and LV groups showed a significant increase in NO synthesis when compared to their respective group under basal condition. On the other hand, in smooth muscle layer, NO fluorescence increased in all groups when compared to their respective group under basal condition. Conclusions: Our results suggest that a single bout of RE promotes vascular endothelium changes in a volume-dependent manner. The 15 sets x 10 repetitions exercise plan induced the greatest levels of NO synthesis.

A simple two stage optimization algorithm for constrained power economic dispatch

International Nuclear Information System (INIS)

Huang, G.; Song, K.

1994-01-01

A simple two stage optimization algorithm is proposed and investigated for fast computation of constrained power economic dispatch control problems. The method is a simple demonstration of the hierarchical aggregation-disaggregation (HAD) concept. The algorithm first solves an aggregated problem to obtain an initial solution. This aggregated problem turns out to be classical economic dispatch formulation, and it can be solved in 1% of overall computation time. In the second stage, linear programming method finds optimal solution which satisfies power balance constraints, generation and transmission inequality constraints and security constraints. Implementation of the algorithm for IEEE systems and EPRI Scenario systems shows that the two stage method obtains average speedup ratio 10.64 as compared to classical LP-based method

Two-stage exchange knee arthroplasty: does resistance of the infecting organism influence the outcome?

Science.gov (United States)

Kurd, Mark F; Ghanem, Elie; Steinbrecher, Jill; Parvizi, Javad

2010-08-01

Periprosthetic joint infection after TKA is a challenging complication. Two-stage exchange arthroplasty is the accepted standard of care, but reported failure rates are increasing. It has been suggested this is due to the increased prevalence of methicillin-resistant infections. We asked the following questions: (1) What is the reinfection rate after two-stage exchange arthroplasty? (2) Which risk factors predict failure? (3) Which variables are associated with acquiring a resistant organism periprosthetic joint infection? This was a case-control study of 102 patients with infected TKA who underwent a two-stage exchange arthroplasty. Ninety-six patients were followed for a minimum of 2 years (mean, 34.5 months; range, 24-90.1 months). Cases were defined as failures of two-stage exchange arthroplasty. Two-stage exchange arthroplasty was successful in controlling the infection in 70 patients (73%). Patients who failed two-stage exchange arthroplasty were 3.37 times more likely to have been originally infected with a methicillin-resistant organism. Older age, higher body mass index, and history of thyroid disease were predisposing factors to infection with a methicillin-resistant organism. Innovative interventions are needed to improve the effectiveness of two-stage exchange arthroplasty for TKA infection with a methicillin-resistant organism as current treatment protocols may not be adequate for control of these virulent pathogens. Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Finite volume at two-loops in chiral perturbation theory

International Nuclear Information System (INIS)

Bijnens, Johan; Rössler, Thomas

2015-01-01

We calculate the finite volume corrections to meson masses and decay constants in two and three flavour Chiral Perturbation Theory to two-loop order. The analytical results are compared with the existing result for the pion mass in two-flavour ChPT and the partial results for the other quantities. We present numerical results for all quantities.

Cervical Vertebral Body’s Volume as a New Parameter for Predicting the Skeletal Maturation Stages

Directory of Open Access Journals (Sweden)

Youn-Kyung Choi

2016-01-01

Full Text Available This study aimed to determine the correlation between the volumetric parameters derived from the images of the second, third, and fourth cervical vertebrae by using cone beam computed tomography with skeletal maturation stages and to propose a new formula for predicting skeletal maturation by using regression analysis. We obtained the estimation of skeletal maturation levels from hand-wrist radiographs and volume parameters derived from the second, third, and fourth cervical vertebrae bodies from 102 Japanese patients (54 women and 48 men, 5–18 years of age. We performed Pearson’s correlation coefficient analysis and simple regression analysis. All volume parameters derived from the second, third, and fourth cervical vertebrae exhibited statistically significant correlations (P<0.05. The simple regression model with the greatest R-square indicated the fourth-cervical-vertebra volume as an independent variable with a variance inflation factor less than ten. The explanation power was 81.76%. Volumetric parameters of cervical vertebrae using cone beam computed tomography are useful in regression models. The derived regression model has the potential for clinical application as it enables a simple and quantitative analysis to evaluate skeletal maturation level.

Effect of Single and Double Stage Chemically Treated Kenaf Fibers on Mechanical Properties of Polyvinyl Alcohol Film

Directory of Open Access Journals (Sweden)

Md Ershad Ali

2014-12-01

Full Text Available The physico-mechanical properties of lignocellulosic kenaf fiber reinforced polyvinyl alcohol (PVA biocomposite films were investigated. To improve the properties of the biocomposite, kenaf fibers were chemically treated separately in a single stage (with Cr2(SO4312(H2O and double stages (with CrSO4 and NaHCO3 to improve the adhesion and compatibility between the kenaf fiber and PVA matrix. PVA was reinforced with various compositions of chemically treated kenaf fiber by using a solution casting technique. Microstructural analyses and mechanical tests were subsequently conducted. Scanning electron microscopic analysis indicated that chemical treatment improved the uniformity distribution of kenaf fiber within the PVA matrix. FTIR and XRD analyses confirmed the presence of chromium on the fiber surface. The tensile strength of PVA reinforced with chemical treated kenaf fiber was found to be higher than those reinforced with untreated kenaf. The Young’s modulus, flexural strength, and flexural modulus increased with fiber loading for both untreated and treated kenaf fiber reinforced PVA films. The double stage treated kenaf fiber showed better mechanical properties and lower moisture uptake than the single stage treated kenaf fiber.

Two-stage energy storage equalization system for lithium-ion battery pack

Science.gov (United States)

Chen, W.; Yang, Z. X.; Dong, G. Q.; Li, Y. B.; He, Q. Y.

2017-11-01

How to raise the efficiency of energy storage and maximize storage capacity is a core problem in current energy storage management. For that, two-stage energy storage equalization system which contains two-stage equalization topology and control strategy based on a symmetric multi-winding transformer and DC-DC (direct current-direct current) converter is proposed with bidirectional active equalization theory, in order to realize the objectives of consistent lithium-ion battery packs voltages and cells voltages inside packs by using a method of the Range. Modeling analysis demonstrates that the voltage dispersion of lithium-ion battery packs and cells inside packs can be kept within 2 percent during charging and discharging. Equalization time was 0.5 ms, which shortened equalization time of 33.3 percent compared with DC-DC converter. Therefore, the proposed two-stage lithium-ion battery equalization system can achieve maximum storage capacity between lithium-ion battery packs and cells inside packs, meanwhile efficiency of energy storage is significantly improved.

Stratified charge rotary engine critical technology enablement. Volume 2: Appendixes

Science.gov (United States)

Irion, C. E.; Mount, R. E.

1992-01-01

This second volume of appendixes is a companion to Volume 1 of this report which summarizes results of a critical technology enablement effort with the stratified charge rotary engine (SCRE) focusing on a power section of 0.67 liters (40 cu. in.) per rotor in single and two rotor versions. The work is a continuation of prior NASA Contracts NAS3-23056 and NAS3-24628. Technical objectives are multi-fuel capability, including civil and military jet fuel and DF-2, fuel efficiency of 0.355 Lbs/BHP-Hr. at best cruise condition above 50 percent power, altitude capability of up to 10Km (33,000 ft.) cruise, 2000 hour TBO and reduced coolant heat rejection. Critical technologies for SCRE's that have the potential for competitive performance and cost in a representative light-aircraft environment were examined. Objectives were: the development and utilization of advanced analytical tools, i.e. higher speed and enhanced three dimensional combustion modeling; identification of critical technologies; development of improved instrumentation; and to isolate and quantitatively identify the contribution to performance and efficiency of critical components or subsystems. A family of four-stage third-order explicit Runge-Kutta schemes is derived that required only two locations and has desirable stability characteristics. Error control is achieved by embedding a second-order scheme within the four-stage procedure. Certain schemes are identified that are as efficient and accurate as conventional embedded schemes of comparable order and require fewer storage locations.

On the prior probabilities for two-stage Bayesian estimates

International Nuclear Information System (INIS)

Kohut, P.

1992-01-01

The method of Bayesian inference is reexamined for its applicability and for the required underlying assumptions in obtaining and using prior probability estimates. Two different approaches are suggested to determine the first-stage priors in the two-stage Bayesian analysis which avoid certain assumptions required for other techniques. In the first scheme, the prior is obtained through a true frequency based distribution generated at selected intervals utilizing actual sampling of the failure rate distributions. The population variability distribution is generated as the weighed average of the frequency distributions. The second method is based on a non-parametric Bayesian approach using the Maximum Entropy Principle. Specific features such as integral properties or selected parameters of prior distributions may be obtained with minimal assumptions. It is indicated how various quantiles may also be generated with a least square technique

Simulation model of a single-stage lithium bromide-water absorption cooling unit

Science.gov (United States)

Miao, D.

1978-01-01

A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.

The determination of time-stationary two-dimensional convection patterns with single-station radars

International Nuclear Information System (INIS)

Freeman, M.P.; Ruohoniemi, J.M.; Greenwald, R.A.

1991-01-01

At the present time, most ground-based radar estimations of ionospheric convection use observations from single-station facilities. This approach requires certain assumptions as to the spatial and/or temporal uniformity of the convection. In this paper the authors present a critical examination of the accuracy of these vector velocity determinations, using realistic modeled flow patterns that are time-stationary but not spatially uniform. They find that under certain circumstances the actual and inferred flow fields show considerable discrepancy, sometimes not even agreeing in the sense of flow direction. Specifically, they show that the natural curvature present in ionospheric convection on varying spatial scales can introduce significant error in the velocity estimate, particularly when the radius of curvature of the flow structure is less than or equal to the radar range to the scattering volume. The presence of flow curvature cannot be detected by radars which determine velocities from measurements in two viewing directions, and it might not be detected by radars using azimuth scanning techniques. Thus they argue that every effort should be made to measure the ionospheric convection by bidirectional or multidirectional observations of a common ionospheric volume and that a synthesis of coherent and incoherent radar observations from different sites is preferable to multidirectional single-station observations using either radar alone. These conclusions are applicable to any Doppler measurement technique and are equally valid for high-latitude wind patterns using Fabry-Perot interferometer techniques

Comparison of two single-breath-held 3-D acquisitions with multi-breath-held 2-D cine steady-state free precession MRI acquisition in children with single ventricles

Energy Technology Data Exchange (ETDEWEB)

Atweh, Lamya A.; Dodd, Nicholas A.; Krishnamurthy, Ramkumar; Chu, Zili D. [Texas Children' s Hospital, EB Singleton Department of Pediatric Radiology, Cardiovascular Imaging, Houston, TX (United States); Pednekar, Amol [Philips Healthcare, Houston, TX (United States); Krishnamurthy, Rajesh [Texas Children' s Hospital, EB Singleton Department of Pediatric Radiology, Cardiovascular Imaging, Houston, TX (United States); Baylor College of Medicine, Department of Radiology, Houston, TX (United States); Baylor College of Medicine, Department of Pediatrics, Houston, TX (United States)

2016-05-15

Breath-held two-dimensional balanced steady-state free precession cine acquisition (2-D breath-held SSFP), accelerated with parallel imaging, is the method of choice for evaluating ventricular function due to its superior blood-to-myocardial contrast, edge definition and high intrinsic signal-to-noise ratio throughout the cardiac cycle. The purpose of this study is to qualitatively and quantitatively compare the two different single-breath-hold 3-D cine SSFP acquisitions using 1) multidirectional sensitivity encoding (SENSE) acceleration factors (3-D multiple SENSE SSFP), and 2) k-t broad-use linear acceleration speed-up technique (3-D k-t SSFP) with the conventional 2-D breath-held SSFP in non-sedated asymptomatic volunteers and children with single ventricle congenital heart disease. Our prospective study was performed on 30 non-sedated subjects (9 healthy volunteers and 21 functional single ventricle patients), ages 12.5 +/- 2.8 years. Two-dimensional breath-held SSFP with SENSE acceleration factor of 2, eight-fold accelerated 3-D k-t SSFP, and 3-D multiple SENSE SSFP with total parallel imaging factor of 4 were performed to evaluate ventricular volumes and mass in the short-axis orientation. Image quality scores (blood myocardial contrast, edge definition and interslice alignment) and volumetric analysis (end systolic volume, end diastolic volume and ejection fraction) were performed on the data sets by experienced users. Paired t-test was performed to compare each of the 3-D k-t SSFP and 3-D multiple SENSE SSFP clinical scores against 2-D breath-held SSFP. Bland-Altman analysis was performed on left ventricle (LV) and single ventricle volumetry. Interobserver and intraobserver variability in volumetric measurements were determined using intraclass coefficients. The clinical scores were highest for the 2-D breath-held SSFP images. Between the two 3-D sequences, 3-D multiple SENSE SSFP performed better than 3-D k-t SSFP. Bland-Altman analysis for volumes

Audiovisual integration in speech perception: a multi-stage process

DEFF Research Database (Denmark)

Eskelund, Kasper; Tuomainen, Jyrki; Andersen, Tobias

2011-01-01

investigate whether the integration of auditory and visual speech observed in these two audiovisual integration effects are specific traits of speech perception. We further ask whether audiovisual integration is undertaken in a single processing stage or multiple processing stages....

Robust Frequency-Domain Constrained Feedback Design via a Two-Stage Heuristic Approach.

Science.gov (United States)

Li, Xianwei; Gao, Huijun

2015-10-01

Based on a two-stage heuristic method, this paper is concerned with the design of robust feedback controllers with restricted frequency-domain specifications (RFDSs) for uncertain linear discrete-time systems. Polytopic uncertainties are assumed to enter all the system matrices, while RFDSs are motivated by the fact that practical design specifications are often described in restricted finite frequency ranges. Dilated multipliers are first introduced to relax the generalized Kalman-Yakubovich-Popov lemma for output feedback controller synthesis and robust performance analysis. Then a two-stage approach to output feedback controller synthesis is proposed: at the first stage, a robust full-information (FI) controller is designed, which is used to construct a required output feedback controller at the second stage. To improve the solvability of the synthesis method, heuristic iterative algorithms are further formulated for exploring the feedback gain and optimizing the initial FI controller at the individual stage. The effectiveness of the proposed design method is finally demonstrated by the application to active control of suspension systems.

Experimental study on an innovative multifunction heat pipe type heat recovery two-stage sorption refrigeration system

International Nuclear Information System (INIS)

Li, T.X.; Wang, R.Z.; Wang, L.W.; Lu, Z.S.

2008-01-01

An innovative multifunction heat pipe type sorption refrigeration system is designed, in which a two-stage sorption thermodynamic cycle based on two heat recovery processes was employed to reduce the driving heat source temperature, and the composite sorbent of CaCl 2 and activated carbon was used to improve the mass and heat transfer performances. For this test unit, the heating, cooling and heat recovery processes between two reactive beds are performed by multifunction heat pipes. The aim of this paper is to investigate the cycled characteristics of two-stage sorption refrigeration system with heat recovery processes. The two sub-cycles of a two-stage cycle have different sorption platforms though the adsorption and desorption temperatures are equivalent. The experimental results showed that the pressure evolutions of two beds are nearly equivalent during the first stage, and desorption pressure during the second stage is large higher than that in the first stage while the desorption temperatures are same during the two operation stages. In comparison with conventional two-stage cycle, the two-stage cycle with heat recovery processes can reduce the heating load for desorber and cooling load for adsorber, the coefficient of performance (COP) has been improved more than 23% when both cycles have the same regeneration temperature of 103 deg. C and the cooling water temperature of 30 deg. C. The advanced two-stage cycle provides an effective method for application of sorption refrigeration technology under the condition of low-grade temperature heat source or utilization of renewable energy

The impact of time between staging PET/CT and definitive chemo-radiation on target volumes and survival in patients with non-small cell lung cancer

International Nuclear Information System (INIS)

Everitt, Sarah; Plumridge, Nikki; Herschtal, Alan; Bressel, Mathias; Ball, David; Callahan, Jason; Kron, Tomas; Schneider-Kolsky, Michal; Binns, David; Hicks, Rodney J.

2013-01-01

Background and purpose: To investigate the impact of treatment delays on radiation therapy (RT) target volumes and overall survival (OS) in patients with non-small cell lung cancer (NSCLC) who underwent two baseline FDG PET/CT scans. Material and methods: Patients underwent a staging (PET1) and RT planning (PET2) FDG PET/CT scan. At PET1 all patients were eligible for radical chemo-RT. OS and progression-free survival (PFS) were compared for patients remaining eligible for radical RT and those treated palliatively because PET2 showed progression. RT target volumes were contoured using PET1 and PET2. Normal tissue doses were compared for patients remaining eligible for radical RT. Results: Eighty-two patients underwent PET2 scans between October 2004 and February 2007. Of these, 21 had a prior PET1 scan, median 23 days apart (range 8–176 days). Six patients (29%) were unsuitable for radical RT after PET2; five received palliative treatment and one received no treatment. Patients treated palliatively had significantly worse OS and PFS than patients treated radically p < 0.001. Mean RT tumour volume increased from 105cc to 198cc (p < 0.005) between scans. Conclusions: Disease progression while awaiting initiation of curative RT in NSCLC is associated with larger treatment volumes and worse survival

Single-organelle tracking by two-photon conversion

Science.gov (United States)

Watanabe, Wataru; Shimada, Tomoko; Matsunaga, Sachihiro; Kurihara, Daisuke; Fukui, Kiichi; Shin-Ichi Arimura, Shin-Ichi; Tsutsumi, Nobuhiro; Isobe, Keisuke; Itoh, Kazuyoshi

2007-03-01

Spatial and temporal information about intracellular objects and their dynamics within a living cell are essential for dynamic analysis of such objects in cell biology. A specific intracellular object can be discriminated by photoactivatable fluorescent proteins that exhibit pronounced light-induced spectral changes. Here, we report on selective labeling and tracking of a single organelle by using two-photon conversion of a photoconvertible fluorescent protein with near-infrared femtosecond laser pulses. We performed selective labeling of a single mitochondrion in a living tobacco BY-2 cell using two-photon photoconversion of Kaede. Using this technique, we demonstrated that, in plants, the directed movement of individual mitochondria along the cytoskeletons was mediated by actin filaments, whereas microtubules were not required for the movement of mitochondria. This single-organelle labeling technique enabled us to track the dynamics of a single organelle, revealing the mechanisms involved in organelle dynamics. The technique has potential application in direct tracking of selective cellular and intracellular structures.

Polymorphisms in CARS are associated with gastric cancer risk: a two-stage case-control study in the Chinese population.

Science.gov (United States)

Tian, Tian; Xiao, Ling; Du, Jiangbo; Zhu, Xun; Gu, Yayun; Qin, Na; Yan, Caiwang; Liu, Li; Ma, Hongxia; Jiang, Yue; Chen, Jiaping; Yu, Hao; Dai, Juncheng

2017-11-01

The cysteinyl transfer RNA synthetase gene (CARS) is located on chromosome band 11p15.5, which is an important tumor-suppressor gene region. Mutations in CARS have been identified in many kinds of cancers; however, evidence for a relationship between genetic variants in CARS and gastric cancer at the population level is still lacking. Thus, we explored the association of variants in CARS with gastric cancer using a two-stage case-control strategy in Chinese. We undertook a two-stage case-control study to investigate the association between polymorphisms in CARS and risk of gastric cancer with use of an Illumina Infinium ® BeadChip and an ABI 7900 system. Four single nucleotide polymorphisms (SNPs) were significantly associated with gastric cancer risk in both the discovery stage and the validation stage after adjustment for age and sex. In addition, the combined results of the two stages showed these SNPs were related to gastric cancer risk (P false discovery rate  ≤ 0.001 for rs384,490, rs729662, rs2071101, and rs7394702). In silico analyses revealed that rs384490 and rs7394702 could affect transcription factor response elements or DNA methylation of CARS, and rs729662 was associated with the prognosis of gastric cancer. Additionally, expression quantitative trait loci analysis showed rs384490 and rs729662 might alter expression of CARS-related genes. The potential functional SNPs in CARS might influence the biological functions of CARS or CARS-related genes and ultimately modify the occurrence and development of gastric cancer in Chinese. Further large-scale population-based studies or biological functional assays are warranted to validate our findings.

Stages of destruction and elastic compression of granular nanoporous carbon medium at high pressures

International Nuclear Information System (INIS)

Neklyudov, I.M.; Ledenyov, O.P.; Bobrova, N.B.; Chupikov, A.A.

2015-01-01

The granular nanoporous carbon medium, made of the cylindrical coal granules of the adsorbent of CKT-3, at an influence by the high pressures from 1 MPa to 3 GPa has been researched. The eight consecutive stages of the material's specific volume change, which is characterized by a certain dependence of the volume change on the pressure change, have been registered. It is shown that there is a linear dependence on the double log-log plot of the material's specific volume change on the pressure for an every stage of considered process. The two stages are clearly distinguished: a stage of material's mechanical destruction, and a stage of elastic compression of material without the disintegration of structure at a nano-scale. The hysteresis dependence of the material's specific volume change on the pressure change at the pressure decrease is observed. The small disperse coal dust particles jettisoning between the high pressure cell and the base plate was observed, resulting in the elastic stress reduction in relation to the small disperse coal dust particles volume. The obtained research data can be used to improve the designs of air filters for the radioactive chemical elements absorption at the NPP with the aims to protect the environment

Objective malignancy grading of squamous cell carcinoma of the lung. Stereologic estimates of mean nuclear size are of prognostic value, independent of clinical stage of disease

DEFF Research Database (Denmark)

Ladekarl, M; Bæk-Hansen, T; Henrik-Nielsen, R

1995-01-01

a projection microscope and a simple test system in fields of vision systematically selected from the whole tumor area of one routine section, five quantitative histopathologic variables were estimated: the mean nuclear volume, the mean nuclear profile area, the density of nuclear profiles, the volume fraction...... of nuclei to tissue, and the number of mitotic profiles per 10(3) nuclear profiles. For each patient, information was recorded regarding sex, age at diagnosis, and clinical stage of disease.RESULTS: Single-factor analyses showed that a favorable prognosis was associated with early clinical stages (Stages I...... and II) and young age (P stage, age, and mean nuclear...

Objective malignancy grading of squamous cell carcinoma of the lung. Stereologic estimates of mean nuclear size are of prognostic value, independent of clinical stage of disease

DEFF Research Database (Denmark)

Ladekarl, M; Bæk-Hansen, T; Henrik-Nielsen, R

1995-01-01

a projection microscope and a simple test system in fields of vision systematically selected from the whole tumor area of one routine section, five quantitative histopathologic variables were estimated: the mean nuclear volume, the mean nuclear profile area, the density of nuclear profiles, the volume fraction...... of nuclei to tissue, and the number of mitotic profiles per 10(3) nuclear profiles. For each patient, information was recorded regarding sex, age at diagnosis, and clinical stage of disease. RESULTS: Single-factor analyses showed that a favorable prognosis was associated with early clinical stages (Stages I...... and II) and young age (P stage, age, and mean nuclear...

FURTHER STUDIES ON THE VARIATION OF SPRAY DEPOSITS IN VINEYARDS WITH AIRFLOW RATE AND VOLUME RATE

Directory of Open Access Journals (Sweden)

Emanuele Cerruto

2007-03-01

Full Text Available The present research, continuing that reported in [2], deals with the spray application subject, so to investigate as volume rate and airflow rate, forward speed being equal, affect the foliar deposition in an espalier vineyard. Experimental trials were carried out by means of an air assisted towed sprayer, equipped with “Albuz ATR” nozzles. To take into account the influence of the development of the trees, the field trials were replicated in two phenological stages with an interval of about one month: “Inflorescences fully developed” (stage 1 and “Beginning of berry touch” (stage 2. A full factorial experiment was carried out for each growth stage, with two airflow rates (3.9 and 7.5 m3/s, three volume rates (103, 216, and 276 L/ha in the first growth stage and 154, 330 and 432 L/ha in the second growth stage, and four replicates, arranged according to a randomised complete block design. Working pressure (1.2 MPa and forward speed (1.4 m/s were kept unchanged for all the trials. The foliar deposition was measured by means of a spectrophotometric technique. The leaves were sampled on two depth layers and two or three heights, according to the trees’ development. The results showed that volume rate did not significantly influence the mean foliar deposition in both the two growth stages, while the highest deposits were obtained with the lowest airflow rate. The airflow rate × volume rate interaction, though not statistically significant, showed that low volume rates together with high airflow rates, result in a noticeable reduction in foliar deposition (29% with respect the grand mean, due to an increase of the spry drift, especially at the first growth stage, when the foliar development is little. These second tests, unlike those described in [2], did not show any positive influence of the airflow rate on the foliar deposition in the inner part of the canopy, so further investigations could be necessary to better understand the

Cerebral staging of lung cancer: is one single contrast-enhanced T1-weighted three-dimensional gradient-echo sequence sufficient?

Energy Technology Data Exchange (ETDEWEB)

Ohana, Mickael; Jeung, Mi-Young; Roy, Catherine [Nouvel Hopital Civil-Hopitaux Universitaires de Strasbourg, Service de Radiologie B/Radiology Department, Strasbourg (France); Bazille, Gauthier [Clinique Saint Anne-Groupe Radiologique MIM, Strasbourg (France)

2014-08-15

Gadolinium-enhanced magnetic resonance imaging (MRI) is the gold standard for cerebral staging in thoracic oncology. We hypothesize that a minimalist examination, consisting of a single contrast-enhanced T1-weighted three-dimensional gradient-echo sequence (CE 3D-GRE), would be sufficient for the cerebral staging of nonsymptomatic lung cancer patients. Seventy nonsymptomatic patients (50 % men; 62 years ± 10.2) referred for cerebral staging of a lung cancer were retrospectively included. All underwent a standard 3 T MRI examination with T1, FLAIR, T2* GRE, diffusion, and CE 3D-GRE sequences, for a total examination time of 20 min. The sole CE 3D-GRE (acquisition time: 6 min) was extracted and blindly interpreted by two radiologists in search of brain metastases. Hemorrhagic features of potential lesions and relevant incidental findings were also noted. Discrepant cases were reviewed by a third reader. The full MRI examination and follow-up studies were used as a reference to calculate sensitivity and specificity of the sole CE 3D-GRE. Thirty-eight point six percent (27 out of 70) of the patients had brain metastases. Performances and reader's agreement with the sole CE 3D-GRE sequence were excellent for the diagnosis of brain metastases (sensitivity = 96.3 %, specificity = 100 %, κ = 0.91) and incidental findings (sensitivity = 85.7 %, specificity = 100 %, κ = 0.62) but insufficient for the identification of hemorrhages within the metastases (sensitivity = 33.3 %, specificity = 85.7 %, κ = 0.47). In the specific case of lung cancer, cerebral staging in nonsymptomatic patients can be efficiently achieved with a minimalistic protocol consisting of a single CE 3D-GRE sequence, completed if positive with a T2* sequence for hemorrhagic assessment, thus halving appointment delays. (orig.)

One-Stage and Two-Stage Schemes of High Performance Synchronous PWM with Smooth Pulses-Ratio Changing

DEFF Research Database (Denmark)

Oleschuk, V.; Blaabjerg, Frede

2002-01-01

This paper presents detailed description of one-stage and two-stage schemes of a novel method of synchronous, pulsewidth modulation (PWM) for voltage source inverters for ac drive application. The proposed control functions provide accurate realization of different versions of voltage space vector...... modulation with synchronization of the voltage waveform of the inverter and with smooth pulse-ratio changing. Voltage spectra do not contain even harmonic and sub-harmonics (combined harmonics) during the whole control range including the zone of overmodulation. Examples of determination of the basic control...

One-stage exchange with antibacterial hydrogel coated implants provides similar results to two-stage revision, without the coating, for the treatment of peri-prosthetic infection.

Science.gov (United States)

Capuano, Nicola; Logoluso, Nicola; Gallazzi, Enrico; Drago, Lorenzo; Romanò, Carlo Luca

2018-03-16

Aim of this study was to verify the hypothesis that a one-stage exchange procedure, performed with an antibiotic-loaded, fast-resorbable hydrogel coating, provides similar infection recurrence rate than a two-stage procedure without the coating, in patients affected by peri-prosthetic joint infection (PJI). In this two-center case-control, study, 22 patients, treated with a one-stage procedure, using implants coated with an antibiotic-loaded hydrogel [defensive antibacterial coating (DAC)], were compared with 22 retrospective matched controls, treated with a two-stage revision procedure, without the coating. At a mean follow-up of 29.3 ± 5.0 months, two patients (9.1%) in the DAC group showed an infection recurrence, compared to three patients (13.6%) in the two-stage group. Clinical scores were similar between groups, while average hospital stay and antibiotic treatment duration were significantly reduced after one-stage, compared to two-stage (18.9 ± 2.9 versus 35.8 ± 3.4 and 23.5 ± 3.3 versus 53.7 ± 5.6 days, respectively). Although in a relatively limited series of patients, our data shows similar infection recurrence rate after one-stage exchange with DAC-coated implants, compared to two-stage revision without coating, with reduced overall hospitalization time and antibiotic treatment duration. These findings warrant further studies in the possible applications of antibacterial coating technologies to treat implant-related infections. III.

A two-stage storage routing model for green roof runoff detention.

Science.gov (United States)

Vesuviano, Gianni; Sonnenwald, Fred; Stovin, Virginia

2014-01-01

Green roofs have been adopted in urban drainage systems to control the total quantity and volumetric flow rate of runoff. Modern green roof designs are multi-layered, their main components being vegetation, substrate and, in almost all cases, a separate drainage layer. Most current hydrological models of green roofs combine the modelling of the separate layers into a single process; these models have limited predictive capability for roofs not sharing the same design. An adaptable, generic, two-stage model for a system consisting of a granular substrate over a hard plastic 'egg box'-style drainage layer and fibrous protection mat is presented. The substrate and drainage layer/protection mat are modelled separately by previously verified sub-models. Controlled storm events are applied to a green roof system in a rainfall simulator. The time-series modelled runoff is compared to the monitored runoff for each storm event. The modelled runoff profiles are accurate (mean Rt(2) = 0.971), but further characterization of the substrate component is required for the model to be generically applicable to other roof configurations with different substrate.

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

Science.gov (United States)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-03-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

Staged regenerative sorption heat pump

Science.gov (United States)

Jones, Jack A. (Inventor)

1995-01-01

A regenerative adsorbent heat pump process and system for cooling and heating a space. A sorbent is confined in a plurality of compressors of which at least four are first stage and at least four are second stage. The first stage operates over a first pressure region and the second stage over a second pressure region which is higher than the first. Sorbate from the first stage enters the second stage. The sorbate loop includes a condenser, expansion valve, evaporator and the compressors. A single sorbate loop can be employed for single-temperature-control such as air conditioning and heating. Two sorbate loops can be used for two-temperature-control as in a refrigerator and freezer. The evaporator temperatures control the freezer and refrigerator temperatures. Alternatively the refrigerator temperature can be cooled by the freezer with one sorbate loop. A heat transfer fluid is circulated in a closed loop which includes a radiator and the compressors. Low temperature heat is exhausted by the radiator. High temperature heat is added to the heat transfer fluid entering the compressors which are desorbing vapor. Heat is transferred from compressors which are sorbing vapor to the heat transfer fluid, and from the heat transfer fluid to the compressors which are desorbing vapor. Each compressor is subjected to the following phases, heating to its highest temperature, cooling down from its highest temperature, cooling to its lowest temperature, and warming up from its lowest temperature. The phases are repeated to complete a cycle and regenerate heat.

Topology as fluid geometry two-dimensional spaces, volume 2

CERN Document Server

Cannon, James W

2017-01-01

This is the second of a three volume collection devoted to the geometry, topology, and curvature of 2-dimensional spaces. The collection provides a guided tour through a wide range of topics by one of the twentieth century's masters of geometric topology. The books are accessible to college and graduate students and provide perspective and insight to mathematicians at all levels who are interested in geometry and topology. The second volume deals with the topology of 2-dimensional spaces. The attempts encountered in Volume 1 to understand length and area in the plane lead to examples most easily described by the methods of topology (fluid geometry): finite curves of infinite length, 1-dimensional curves of positive area, space-filling curves (Peano curves), 0-dimensional subsets of the plane through which no straight path can pass (Cantor sets), etc. Volume 2 describes such sets. All of the standard topological results about 2-dimensional spaces are then proved, such as the Fundamental Theorem of Algebra (two...

Feasibility study of generating ultra-high harmonic radiation with a single stage echo-enabled harmonic generation scheme

Energy Technology Data Exchange (ETDEWEB)

Zhou, Kaishang, E-mail: zhoukaishang@sinap.ac.cn; Feng, Chao, E-mail: fengchao@sinap.ac.cn; Wang, Dong, E-mail: wangdong@sinap.ac.cn

2016-10-21

The echo enabled harmonic generation (EEHG) scheme holds the ability for the generation of fully coherent soft x-ray free-electron laser (FEL) pulses directly from external UV seeding sources. In this paper, we study the feasibility of using a single stage EEHG to generate coherent radiation in the “water window” and beyond. Using the high-order operating modes of the EEHG scheme, intensive numerical simulations have been performed considering various three-dimensional effects. The simulation results demonstrated that coherent soft x-ray radiation at 150th harmonic (1.77 nm) of the seed can be produced by a single stage EEHG. The decreasing of the final bunching factor at the desired harmonic caused by intra beam scattering (IBS) effect has also been analyzed.

Determinants of the incidence of childhood asthma: a two-stage case-control study.

Science.gov (United States)

Martel, Marie-Josée; Rey, Evelyne; Malo, Jean-Luc; Perreault, Sylvie; Beauchesne, Marie-France; Forget, Amélie; Blais, Lucie

2009-01-15

Extensive literature exists on potential risk factors for childhood asthma. To the authors' knowledge, no investigators have yet attempted to disentangle the effects of those determinants within a single study setting. The authors aimed to evaluate the independent effects of 47 potential determinants (from the prenatal, perinatal, and childhood periods) of asthma development in children within the first 10 years of life. From a Canadian birth cohort of 26,265 children (1990-2002), a 2-stage case-control study was conducted. In the first stage, 20 controls per case were selected from 3 administrative databases. In the second stage, selected mothers were mailed questionnaires for assessment of additional determinants. Increased risks of childhood asthma were found for > or =1 previous diagnosis of bronchopulmonary disease and atopic dermatitis in the child, oxygen administration after birth, prescription of antibiotics within the first 6 months of life, male gender, asthma during pregnancy, use of antibiotics during pregnancy, maternal receipt of social aid, paternal asthma, and asthma in siblings. Protective effects included use of intranasal corticosteroids during pregnancy, having a wood-burning fireplace, having pets in the home prior to the index date, breastfeeding, and day-care attendance. This study allowed the authors to identify, within a single setting, the most influential determinants of childhood asthma among 47 predictors assessed for the prenatal, perinatal, and childhood periods.

Effect of fluid loading on left ventricular volume and stroke volume variability in patients with end-stage renal disease: a pilot study

Science.gov (United States)

Kanda, Hirotsugu; Hirasaki, Yuji; Iida, Takafumi; Kanao-Kanda, Megumi; Toyama, Yuki; Kunisawa, Takayuki; Iwasaki, Hiroshi

2015-01-01

Purpose The aim of this study was to investigate fluid loading-induced changes in left ventricular end-diastolic volume (LVEDV) and stroke volume variability (SVV) in patients with end-stage renal disease (ESRD) using real-time three-dimensional transesophageal echocardiography and the Vigileo-FloTrac system. Patients and methods After obtaining ethics committee approval and informed consent, 28 patients undergoing peripheral vascular procedures were studied. Fourteen patients with ESRD on hemodialysis (HD) were assigned to the HD group and 14 patients without ESRD were assigned to the control group. Institutional standardized general anesthesia was provided in both groups. SVV was measured using the Vigileo-FloTrac system. Simultaneously, a full-volume three-dimensional transesophageal echocardiography dataset was acquired to measure LVEDV, left ventricular end-systolic volume, and left ventricular ejection fraction. Measurements were obtained before and after loading 500 mL hydroxyethyl starch over 30 minutes in both groups. Results In the control group, intravenous colloid infusion was associated with a significant decrease in SVV (13.8%±2.6% to 6.5%±2.6%, P<0.001) and a significant increase in LVEDV (83.6±23.4 mL to 96.1±28.8 mL, P<0.001). While SVV significantly decreased after infusion in the HD group (16.2%±6.0% to 6.2%±2.8%, P<0.001), there was no significant change in LVEDV. Conclusion Our preliminary data suggest that fluid responsiveness can be assessed not by LVEDV but also by SVV due to underlying cardiovascular pathophysiology in patients with ESRD. PMID:26527879

Blood volume determination with two radioisotopes: application to non-cardiogenic shock

International Nuclear Information System (INIS)

Mallet, J.-J.

1975-01-01

Knowledge of the circulating blood volume may be of great assistance in the study of clinical shock. The isotope dilution principle is used to measure both plasma and red cell volume. Considering the increased capillary permeability in patients in shock, it may be of considerable value to quantify the diffusion of liquid through the capillary walls. A double determination of the volume of distribution of the tracer is to be envisaged. Two methods are described. The first one uses a non-diffusible tracer (sup(99m)Tc-labelled red cells) confined to the intravascular space, giving a measure of the intravascular blood volume. The latter uses 131 I-labelled serum albumin which remains, usually, in the vascular bed, but is able to diffuse through the pores of the capillary membrane, because of its low molecular weight. A resulting increase of the tracer volume distribution, with regard to this capillary diffusion is considered. A comparison of the two methods used simultaneously appear to provide information on the possible liquid diffusion in clinical shock. The results obtained in several pathological conditions are described. They enable conclusion to be drawn on the possibility of errors introduced by the use of 131 I-labelled serum albumin alone in determining the circulating blood volume in clinical shock [fr

Giant volume magnetostriction in the Y{sub 2}Fe{sub 17} single crystal at room temperature

Energy Technology Data Exchange (ETDEWEB)

Nikitin, S. A., E-mail: nikitin@phys.msu.ru; Pankratov, N. Yu.; Smarzhevskaya, A. I.; Politova, G. A. [Physics Faculty, Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Pastushenkov, Yu. G., E-mail: yupast@mail.ru; Skokov, K. P. [Physics Faculty, Tver State University, 170100 Tver (Russian Federation); Moral, A. del [Laboratorio de Magnetismo de Slidos, Departamento de Fisica de Materia Condensada and Instituto de Ciencia de Materiales de Aragn, Facultad de Ciencias, Universidad de Zaragoza-C.S.I.C, E-50009 Zaragoza (Spain)

2015-05-21

An investigation of the Y{sub 2}Fe{sub 17} compound belonging to the class of intermetallic alloys of rare-earth and 3d-transition metals is presented. The magnetization, magnetostriction, and thermal expansion of the Y{sub 2}Fe{sub 17} single crystal were studied. The forced magnetostriction and magnetostriction constants were investigated in the temperature range of the magnetic ordering close to the room temperature. The giant field induced volume magnetostriction was discovered in the room temperature region in the magnetic field up to 1.2 T. The contributions of both anisotropic single-ion and isotropic pair exchange interactions to the volume magnetostriction and magnetostriction constants were determined. The experimental results were interpreted within the framework of the Standard Theory of Magnetostriction and the Landau thermodynamic theory. It was found out that the giant values of the volume magnetostriction were caused by the strong dependence of the 3d-electron Coulomb charge repulsion on the deformations and width of the 3d-electron energy band.

Creep in single crystals of γ single phase Ni-20Cr alloy and evolution of dynamic recrystallization

International Nuclear Information System (INIS)

Matsuo, T.; Terada, Y.; Takahashi, S.; Ishiwari, Y.

2000-01-01

The creep rate - time and the creep rate - strain curves of the single crystals of γ single phase Ni-20 mass%Cr alloy have been investigated at 1173 K under the wide stress range of 19.6 to 98 MPa, and compared with those of polycrystals. The orientation corresponding to the stress axis of the single crystals were chosen within the standard stereographic triangle. The creep curve in the Ni-20 mass%Cr single crystal consists of a transient stage and an accelerating stage without a steady state stage. The transient stage has two steps. In the first step, the creep rate slightly decreases, and in the second step, the decrease in creep rate becomes prominent with increasing the testing time. With decreasing the stress, the extension of transient stage becomes prominent, and by this extension, the decreasing ratio of the creep rate in transient stage is enlarged. At the lowest stress of 19.6 MPa, the most prominent extension of transient stage and the more than two order decrease in creep rate in transient stage are detected. The creep interrupting tests have been conducted at the stress of 29.4 MPa in the strain range of 0.1 to 0.6 to examine the appearance of dynamically recrystallized grains. At the strain of 0.1 corresponding to the end of the first step in transient stage, a straight subboundary parallel to slip plane appears in a wide distance of a few hundreds micrometers. With increasing the strain, the straight subboundary turns to waved one. At the strain showing the minimum creep rate, a lot of evolved subgrains appear. At the strain corresponding to the early stage of accelerating creep, dynamically recrystallized grains appear. It is confirmed that the onset of accelerating creep well corresponds to the appearance of dynamically recrystallized grains. In the single crystal creep ruptured, the whole gage portion turns to polycrystal with equiaxed grains having a diameter of 150 μm. (orig.)

Two phase sampling

CERN Document Server

Ahmad, Zahoor; Hanif, Muhammad

2013-01-01

The development of estimators of population parameters based on two-phase sampling schemes has seen a dramatic increase in the past decade. Various authors have developed estimators of population using either one or two auxiliary variables. The present volume is a comprehensive collection of estimators available in single and two phase sampling. The book covers estimators which utilize information on single, two and multiple auxiliary variables of both quantitative and qualitative nature. Th...