WorldWideScience

Sample records for cubical stand-alone interbody

  1. Stand-Alone Lateral Interbody Fusion for the Treatment of Low-Grade Degenerative Spondylolisthesis

    Directory of Open Access Journals (Sweden)

    Luis Marchi

    2012-01-01

    Full Text Available The purpose of this paper was to investigate the stand-alone lateral interbody fusion as a minimally invasive option for the treatment of low-grade degenerative spondylolisthesis with a minimum 24-month followup. Prospective nonrandomized observational single-center study. 52 consecutive patients (67.6±10 y/o; 73.1% female; 27.4±3.4 BMI with single-level grade I/II single-level degenerative spondylolisthesis without significant spine instability were included. Fusion procedures were performed as retroperitoneal lateral transpsoas interbody fusions without screw supplementation. The procedures were performed in average 73.2 minutes and with less than 50cc blood loss. VAS and Oswestry scores showed lasting improvements in clinical outcomes (60% and 54.5% change, resp.. The vertebral slippage was reduced in 90.4% of cases from mean values of 15.1% preoperatively to 7.4% at 6-week followup (P<0.001 and was maintained through 24 months (7.1%, P<0.001. Segmental lordosis (P<0.001 and disc height (P<0.001 were improved in postop evaluations. Cage subsidence occurred in 9/52 cases (17% and 7/52 cases (13% spine levels needed revision surgery. At the 24-month evaluation, solid fusion was observed in 86.5% of the levels treated. The minimally invasive lateral approach has been shown to be a safe and reproducible technique to treat low-grade degenerative spondylolisthesis.

  2. [Biomechanicsl evaluation of a stand-alone interbody fusion cage based on porous TiO2/glass-ceramic on the human cervical spine].

    Science.gov (United States)

    Korinth, M C; Moersch, S; Ragoss, C; Schopphoff, E

    2003-12-01

    Recently, there has been a rapid increase in the use of cervical spine interbody fusion cages, differing in design and biomaterial used, in competition to autologous iliac bone graft and bone cement (PMMA). Limited biomechanical differences in primary stability, as well as advantages and disadvantages of each cage or material have been investigated in studies, using an in vitro human cervical spine model. 20 human cervical spine specimens were tested after fusion with either a cubical stand-alone interbody fusion cage manufactured from a new porous TiO2/glass composite (Ecopore) or PMMA after discectomy. Non-destructive biomechanical testing was performed, including flexion/extension and lateral bending using a spine testing apparatus. Three-dimensional segmental range of motion (ROM) was evaluated using an ultrasound measurement system. ROM increased more in flexion/extension and lateral bending after PMMA fusion (26.5%/36.1%), then after implantation of the Ecopore-cage (8.1%/7.8%). In this first biomechanical in vitro examination of a new porous ceramic bone replacement material a) the feasibility and reproducibility of biomechanical cadaveric cervical examination and its applicability was demonstrated, b) the stability of the ceramic cage as a stand alone interbody cage was confirmed in vitro, and c) basic information and knowledge for our intended biomechanical and histological in vivo testing, after implantation of Ecopore in cervical sheep spines, were obtained.

  3. Maintenance of Segmental Lordosis and Disk Height in Stand-alone and Instrumented Extreme Lateral Interbody Fusion (XLIF).

    Science.gov (United States)

    Malham, Gregory M; Ellis, Ngaire J; Parker, Rhiannon M; Blecher, Carl M; White, Rohan; Goss, Ben; Seex, Kevin A

    2017-03-01

    A prospective single-surgeon nonrandomized clinical study. To evaluate the radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for stand-alone XLIF. XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that stand-alone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. A fixation algorithm was developed after evaluation of patient outcomes from the surgeon's first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine the requirement for supplemental fixation. Preoperative, postoperative, and 12-month follow-up computed tomography scans were measured for segmental and global lumbar lordosis and posterior disk height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Preoperatively to 12-month follow-up there were increases in segmental lordosis (7.9-9.4 degrees, P=0.0497), lumbar lordosis (48.8-55.2 degrees, P=0.0328), and disk height (3.7-5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%), and MCS (16.1%) for stand-alone XLIF. For instrumented XLIF, segmental lordosis (7.6-10.5 degrees, P=0.0120) and disk height (3.5-5.6 mm, Plordosis decreased (51.1-45.8 degrees, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%), and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) stand-alone patients. The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for stand-alone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and

  4. Biomechanical comparison of a new stand-alone anterior lumbar interbody fusion cage with established fixation techniques – a three-dimensional finite element analysis

    Directory of Open Access Journals (Sweden)

    Hsieh Pang-Hsing

    2008-06-01

    Full Text Available Abstract Background Initial promise of a stand-alone interbody fusion cage to treat chronic back pain and restore disc height has not been realized. In some instances, a posterior spinal fixation has been used to enhance stability and increase fusion rate. In this manuscript, a new stand-alone cage is compared with conventional fixation methods based on the finite element analysis, with a focus on investigating cage-bone interface mechanics and stress distribution on the adjacent tissues. Methods Three trapezoid 8° interbody fusion cage models (dual paralleled cages, a single large cage, or a two-part cage consisting of a trapezoid box and threaded cylinder were created with or without pedicle screws fixation to investigate the relative importance of the screws on the spinal segmental response. The contact stress on the facet joint, slip displacement of the cage on the endplate, and rotational angle of the upper vertebra were measured under different loading conditions. Results Simulation results demonstrated less facet stress and slip displacement with the maximal contact on the cage-bone interface. A stand-alone two-part cage had good slip behavior under compression, flexion, extension, lateral bending and torsion, as compared with the other two interbody cages, even with the additional posterior fixation. However, the two-part cage had the lowest rotational angles under flexion and torsion, but had no differences under extension and lateral bending. Conclusion The biomechanical benefit of a stand-alone two-part fusion cage can be justified. This device provided the stability required for interbody fusion, which supports clinical trials of the cage as an alternative to circumferential fixations.

  5. [Application of a stand-alone interbody fusion cage based on a novel porous TiO2/glass composite. I. Implantation in the sheep cervical spine and radiological evaluation].

    Science.gov (United States)

    Korinth, M C; Hero, T; Mahnken, A H; Ragoss, C; Scherer, K

    2004-12-01

    Animals are becoming more and more common as in vitro and in vivo models for the human spine. Especially the sheep cervical spine is stated to be of good comparability and usefulness in the evaluation of in vivo radiological, biomechanical and histological behaviour of new bone replacement materials, implants and cages for cervical spine interbody fusion. In preceding biomechanical in vitro examination human cervical spine specimens were tested after fusion with either a cubical stand-alone interbody fusion cage manufactured from a new porous TiO/glass composite (Ecopore) or polymethyl-methacrylate (PMMA) after discectomy. First experience with the use of the new material and its influence on the primary stability after in vitro application were gained. After fusion of 10 sheep cervical spines in the levels C2/3 and C4/5 in each case with PMMA and with an Ecopore-cage, radiologic as well as computertomographic examinations were performed postoperatively and every 4 weeks during the following 2 and 4 months, respectively. Apart from establishing our animal model, we analysed the radiological changes and the degree of bony fusion of the operated segments during the course. In addition we performed measurements of the corresponding disc space heights (DSH) and intervertebral angles (IVA) for comparison among each other, during the course and with the initial values. Immediately after placement of both implants in the disc spaces the mean DSH and IVA increased (34.8% and 53.9%, respectively). During the following months DSH decreased to a greater extent in the Ecopore-segments than in the PMMA-segments, even to a value below the initial value (p>0.05). Similarly, the IVA decreased in both groups in the postoperative time lapse, but more distinct in the Ecopore-segments (pmodel of the sheep cervical spine. Distinct radiological changes regarding evident subsidence and detectable fusion of the segments, operated on with the new biomaterial, were seen. We demonstrated the

  6. Segmental kyphosis after cervical interbody fusion with stand-alone polyetheretherketone (PEEK) cages: a comparative study on 2 different PEEK cages.

    Science.gov (United States)

    Kim, Chi Heon; Chung, Chun Kee; Jahng, Tae-Ahn; Park, Sung Bae; Sohn, Seil; Lee, Sungjoon

    2015-02-01

    Retrospective comparative study. Two polyetheretherketone (PEEK) cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion. Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion. Although PEEK material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design. A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round tube-type (Solis; 18 patients, S-group) or a trapezoidal tube-type (MC+; 23 patients, M-group) cage was used. The contact area between the cage and the vertebral body is larger in MC+ than in Solis, and anchoring pins were present in the Solis cage. The effect of the cage type on the segmental angle (SA) (lordosis vs. kyphosis) at postoperative month 24 was analyzed. Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (P=0.84). The SA was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (P=0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (P=0.01). The patients in M-group were 7.83 times more likely than patients in S-group (P=0.04; odds ratio, 7.83; 95% confidence interval, 1.09-56.28) not to develop segmental kyphosis. The design of the PEEK cage used may influence the SA, and this association needs to be considered when using stand-alone PEEK cages.

  7. Stand-alone XLIF

    DEFF Research Database (Denmark)

    Hansen, E. J.; Simony, A.; Hummel, Stefan

    2015-01-01

    and clinical/radiological results in 22 patients treated with XLIF procedure for DS or degenerative disc disease (DDD). Material and methods: 22 consecutive patients with DS underwent surgery with the XLIF stand-alone procedure, with follow-up of 24 months. Clinical outcome scores were collected. Complications......Introduction: Adult thoracolumbar degeneration is an increasing challenge in the aging population. With age the progressive degeneration of the discs leads to an asymmetric collapse and a thoracolumbar coronal plane deformity, a degenerative scoliosis (DS). Aim: To evaluate the complication rate......-year follow-up, with a 31.8% revision rate. Due to the high revision rate we recommend supplementary posterior instrumentation, to achieve a higher fusion rate. When considering XLIF-stand-alone procedure for DS or DDD without supplemental posterior instrumentation, only single-level disease should...

  8. Solar Charged Stand Alone Inverter

    OpenAIRE

    M.Vasugi; Prof R.Jayaraman

    2014-01-01

    This paper deals with solar powered stand alone inverter which converts the variable dc output of a photovoltaic solar panel into ac that can be fed to loads. Stand alone inverters are used in systems where the inverter get its energy from batteries charged by photo voltaic arrays. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. This charge discharge controller is needed to prevent the battery from being overcharged o...

  9. The Stand-alone Heliostat

    International Nuclear Information System (INIS)

    Garcia Navajas, G. I.; Egea Gea, A.

    2000-01-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-nr, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modem working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modem. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced.by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs

  10. Basic Stand Alone Medicare Inpatient Claims PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Inpatient Public Use Files (PUF) named CMS 2008 BSA Inpatient Claims PUF with information from 2008 Medicare...

  11. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  12. Stand alone photovoltaic systems: guarantee of results

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This study aims to provide a guarantee of results for system performance for users of stand-alone photovoltaic (PV) systems, which have no back-up generator. The appropriate main performance criterion for PV systems is that a specified load is supplied with power either continuously or intermittently whenever the load requires power. A methodology to evaluate the power availability of stand-alone PV systems has been developed as part of the project, which encompasses power losses due to weather variations. The guarantee of results produced allows users to compare system designs from different manufacturers. (UK)

  13. Stand-alone photovoltaic applications. Lessons learned

    International Nuclear Information System (INIS)

    Loois, G.; Van Hemert, B.

    1999-02-01

    The IEA Photovoltaic Power Systems Programme (PVPS) is one of the collaborative R and D agreements established within the IEA. The objective of Task III is to promote and facilitate the exchange of information and experiences in the field of PV Systems in Stand-alone and Island Applications (SAPV). The book focuses on the practical experiences gained, and does not aim to provide a complete manual on SAPV. When Task III started its activities in 1993, a collection of 50 'State of the art' projects was published in the book 'Examples of Stand-Alone Photovoltaic Systems'. This publication marked the base line for the work of the task. Now, in 1998, the showcases from each country demonstrate the lessons learned in five years of cooperation. The book consists of two parts. The first part contains eight chapters dealing with a specific aspect of stand-alone PV. The second part introduces 14 national showcase projects in a systematic presentation. Each chapter and showcase can be read independently from the rest of the book. Chapter 2, contributed by The Netherlands, analyses the market for stand-alone PV systems. It gives an overview of the 'traditional' application of stand-alone PV, which is the electrification of remote buildings and which has been addressed in depth in other publications. The focus is on the market niches of service applications that are also interesting for more densely populated areas, e.g. in industrialised countries. The United Kingdom illustrates the economic aspects in Chapter 3. Cost comparisons are made, but more important is the illustration of the non-financial considerations that make PV the preferred choice as a power source for many applications. Switzerland explores in Chapter 4 (financing aspects) different financing mechanisms, and financial policies used to overcome the initial cost barrier. Most of these approaches have been applied in developing countries rather than in the western world. Using various examples from all over the

  14. Developing a mobile stand alone photovoltaic generator

    International Nuclear Information System (INIS)

    Soler-Bientz, R.; Ricalde-Cab, L.O.; Solis-Rodriguez, L.E.

    2006-01-01

    This paper describes a recent work developed to create a mobile stand alone photovoltaic generator that can be easily relocated in remote areas to evaluate the feasibility of photovoltaic energy applications. A set of sensors were installed to monitor the electric current and voltage of the energy generated, the energy stored and the energy used by the loads that may be connected to the system. Other parameters like solar radiations (both on the horizontal and on the photovoltaic generation planes) and temperatures (of both the environment and the photovoltaic module) were monitored. This was done while considering the important role of temperature in the photovoltaic module performance. Finally, a measurement and communication hardware was installed to interface the system developed with a conventional computer. In this way, the performance of the overall system in real rural conditions could be evaluated efficiently. Visual software that reads, visualizes and saves the data generated by the system was also developed by means of the LabVIEW programming environment

  15. 39 CFR 122.2 - Stand-alone special services.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Stand-alone special services. 122.2 Section 122.2 Postal Service UNITED STATES POSTAL SERVICE POST OFFICE SERVICES [DOMESTIC MAIL] SERVICE STANDARDS FOR MARKET-DOMINANT SPECIAL SERVICES PRODUCTS § 122.2 Stand-alone special services. (a) The service standard...

  16. Stand-alone induction generators for small water power schemes

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Adam [Intermediate Technology Development Group, Rugby (United Kingdom); Smith, Nigel [Smith Associates, Nottingham (United Kingdom)

    1996-04-01

    Conventional technology for isolated power generation is the synchronous generator. Using stand-alone induction generators has proved to have tremendous advantages in remote regions of developing countries, where electricity has significant social benefits. (author)

  17. Basic Stand Alone Medicare DME Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Durable Medical Equipment (DME) Line Items Public Use Files (PUF) with information from Medicare DME claims. The...

  18. Basic Stand Alone Skilled Nursing Facility Beneficiary PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Skilled Nursing Facility (SNF) Beneficiary Public Use Files (PUF) with information from Medicare SNF claims. The...

  19. The stand-alone test and decreasing serial cost sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Thorlund-Petersen, Lars

    2000-01-01

    The rule of decreasing serial cost sharing defined in de Frutos [1] over the class of concave cost functions may violate the important stand-alone test. Sufficient conditions for the test to be satisfied are given, in terms of individual rationality as well as coalitional stability...

  20. Stand-alone solutions, computer networks and extern communications

    International Nuclear Information System (INIS)

    Tarschisch, H.

    1988-01-01

    The advantages of local networks over stand-alone solutions are presented. Of the local networks (LAN), two are presently at the center of attention: the bus and the ring. ETHERNET and the IBM-Token-Ring are described as typical examples. Access to public networks, especially TELEPAC and ISDN, is discussed. 12 figs

  1. Ampere hour method of sizing a stand alone photovoltaic system ...

    African Journals Online (AJOL)

    Stand-alone photovoltaic power systems are natural options for application in electrification of remote areas which are not served by the grid electricity supply system. An ampere-hour ... Sizing of the balance-of-system were carefully handled to avoid undersizing or oversizing and subsequent variation in supply reliability.

  2. Models for a stand-alone PV system

    DEFF Research Database (Denmark)

    Hansen, A.D.; Sørensen, Poul Ejnar; Hansen, L.H.

    2001-01-01

    are based on the model descriptions found in the literature. The battery model is developed at UMASS and is known as the Kinetic Battery Model(KiBaM). The other component models in the PV system are based on simple electrical knowledge. The implementation is done using Matlab/Simulink, a simulation program......This report presents a number of models for modelling and simulation of a stand-alone photovoltaic (PV) system with a battery bank verified against a system installed at Risø National Laboratory. The work has been supported by the Danish Ministry ofEnergy, as a part of the activities in the Solar...... Energy Centre Denmark. The study is carried out at Risø National Laboratory with the main purpose to establish a library of simple mathematical models for each individual element of a stand-alone PVsystem, namely solar cells, battery, controller, inverter and load. The models for PV module and battery...

  3. Optimal sizing method for stand-alone photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    Groumpos, P P; Papageorgiou, G

    1987-01-01

    The total life-cycle cost of stand-alone photovoltaic (SAPV) power systems is mathematically formulated. A new optimal sizing algorithm for the solar array and battery capacity is developed. The optimum value of a balancing parameter, M, for the optimal sizing of SAPV system components is derived. The proposed optimal sizing algorithm is used in an illustrative example, where a more economical life-cycle cost has bene obtained. The question of cost versus reliability is briefly discussed.

  4. Models for a stand-alone PV system[Photovoltaic

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Soerensen, P.; Hansen, L.H.; Bindner, H.

    2000-12-01

    This report presents a number of models for modelling and simulation of a stand-alone photovoltaic (PV) system with a battery bank verified against a system installed at Risoe National Laboratory. The work has been supported by the Danish Ministry of Energy, as a part of the activities in the Solar Energy Centre Denmark. The study is carried out at Risoe National Laboratory with the main purpose to establish a library of simple mathematical models for each individual element of a stand-alone PV system, namely solar cells, battery, controller, inverter and load. The models for PV module and battery are based on the model descriptions found in the literature. The battery model is developed at UMASS and is known as the Kinetic Battery Model (KiBaM). The other component models in the PV system are based on simple electrical knowledge. The implementation is done using Matlab/Simulink, a simulation program that provides a graphical interface for building models as modular block diagrams. The non-linear behaviour of the battery, observed in the measurements, is investigated and compared to the KiBaM model's performance. A set of linear Black box models are estimated based on the battery measurements. The performance of the best linear Black box model is compared to the KiBaM model. A validation of each of the implemented mathematical model is performed by an interactive analysis and comparison between simulation results and measurements, acquired from the stand-alone PV system at Risoe. (au)

  5. Size-Prediction Analysis for Stand-Alone Photovoltaic System

    International Nuclear Information System (INIS)

    Erusiafe, N. E.; Chendo, M. A. C.

    2002-01-01

    The cost - effectiveness of photovoltaic (PV) generator depends, among others, on its ability to satisfy energy demand and the cost of achieving this. In this work a step - by - step procedure for predicting the size of the main components of a stand - alone PV system (array and storage) is presented. The results yield an expression which can he used lo determine the size of both components at optimum cost and desired reliability. The result from this work compare favourably with some earlier works in that, the system sizes shows some degree of agreement

  6. Availability model of stand-alone photovoltaic system

    Science.gov (United States)

    Mazurek, G.

    2017-08-01

    In this paper we present a simple, empirical model of stand-alone photovoltaic power system availability. The model is a final result of five-year long studies and ground measurements of solar irradiation carried out in Central Europe. The obtained results facilitate sizing of PV modules that have to be installed with taking into account system's availability level in each month of a year. The model can be extended to different geographical locations, with help of local meteorological data or solar irradiation datasets derived from satellite measurements.

  7. Future UK markets for stand-alone renewable energy systems

    International Nuclear Information System (INIS)

    Paish, O.

    1999-01-01

    A study to identify and quantify the market for stand-alone renewable energy supplies of power (photovoltaics, wind and micro-hydro electricity systems) was described. The study focused on small systems, generally less than a few kW installed capacity. It was suggested that in the UK, the emphasis on grid-connected renewable energy technologies (RETs) has blurred the fact that it is 'off-grid' renewable systems that can offer more immediate real commercial markets for the renewables business. With the likelihood of a significant increase in demand for renewables world wide over the next ten years, the UK needs to make a special effort to become involved

  8. Benchmarking the Collocation Stand-Alone Library and Toolkit (CSALT)

    Science.gov (United States)

    Hughes, Steven; Knittel, Jeremy; Shoan, Wendy; Kim, Youngkwang; Conway, Claire; Conway, Darrel J.

    2017-01-01

    This paper describes the processes and results of Verification and Validation (VV) efforts for the Collocation Stand Alone Library and Toolkit (CSALT). We describe the test program and environments, the tools used for independent test data, and comparison results. The VV effort employs classical problems with known analytic solutions, solutions from other available software tools, and comparisons to benchmarking data available in the public literature. Presenting all test results are beyond the scope of a single paper. Here we present high-level test results for a broad range of problems, and detailed comparisons for selected problems.

  9. Enhanced current and voltage regulators for stand-alone applications

    DEFF Research Database (Denmark)

    Federico, de Bosio; Pastorelli, Michele; Antonio DeSouza Ribeiro, Luiz

    2016-01-01

    State feedback decoupling permits to achieve a better dynamic response for Voltage Source in stand-alone applications. The design of current and voltage regulators is performed in the discrete-time domain since it provides better accuracy and allows direct pole placement. As the attainable...... bandwidth of the current loop is mainly limited by computational and PWM delays, a lead compensator structure is proposed to overcome this limitation. The design of the voltage regulator is based on the Nyquist criterion, verifying to guarantee a high sensitivity peak. Discrete-time domain implementation...

  10. Hydrogen Gas Production in a Stand-Alone Wind Farm

    Directory of Open Access Journals (Sweden)

    M. Naziry Kordkandy

    2017-04-01

    Full Text Available This paper is analyzing the operation of a stand-alone wind farm with variable speed turbines, permanent magnet synchronous generators (PMSG and a system for converting wind energy during wind speed variations. On this paper, the design and modeling of a wind system which uses PMSG’s to provide the required power of a hydrogen gas electrolyzer system, is discussed. This wind farm consists of three wind turbines, boost DC-DC converters, diode full bridge rectifiers, permanent magnet synchronous generators, MPPT control and a hydrogen gas electrolyzer system. The MPPT controller based on fuzzy logic is designed to adjust the duty ratio of the boost DC-DC converters to absorb maximum power. The proposed fuzzy logic controller assimilates, with (PSF MPPT algorithm which generally used to absorb maximum power from paralleled wind turbines and stores it in form of hydrogen gas. The system is modeled and its behavior is studied using the MATLAB software.

  11. Magnetic field measurements near stand-alone transformer stations.

    Science.gov (United States)

    Kandel, Shaiela; Hareuveny, Ronen; Yitzhak, Nir-Mordechay; Ruppin, Raphael

    2013-12-01

    Extremely low-frequency (ELF) magnetic field (MF) measurements around and above three stand-alone 22/0.4-kV transformer stations have been performed. The low-voltage (LV) cables between the transformer and the LV switchgear were found to be the major source of strong ELF MFs of limited spatial extent. The strong fields measured above the transformer stations support the assessment method, to be used in future epidemiological studies, of classifying apartments located right above the transformer stations as highly exposed to MFs. The results of the MF measurements above the ground around the transformer stations provide a basis for the assessment of the option of implementing precautionary procedures.

  12. Integral type small PWR with stand-alone safety

    International Nuclear Information System (INIS)

    Makihara, Yoshiaki

    2001-01-01

    A feasibility study is achieved on an integral type small PWR with stand-alone safety. It is designed to have the following features. (1) The coolant does not leak out at any accidental condition. (2) The fuel failure does never occur while it is supposed on the large scale PWR at the design base accident. (3) At any accidental condition the safety is secured without any support from the outside (stand-alone safety secure). (4) It has self-regulating characteristics and easy controllability. The above features can be satisfied by integrate the steam generator and CRDM in the reactor vessel while the pipe line break has to be considered on the conventional PWR. Several counter measures are planned to satisfy the above features. The economy feature is also attained by several simplifications such as (1) elimination of main coolant piping and pressurizer by the integration of primary cooling system and self-pressurizing, (2) elimination of RCP by application of natural circulating system, (3) elimination of ECCS and accumulator by application of static safety system, (4) large scale volume reduction of the container vessel by application of integrated primary cooling system, (5) elimination of boric acid treatment by deletion of chemical shim. The long operation period such as 10 years can be attained by the application of Gd fuel in one batch refueling. The construction period can be shortened by the standardizing the design and the introduction of modular component system. Furthermore the applicability of the reduced modulation core is also considered. (K. Tsuchihashi)

  13. A control strategy for PV stand-alone applications

    Science.gov (United States)

    Slouma, S.; Baccar, H.

    2015-04-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system.

  14. A control strategy for PV stand-alone applications

    International Nuclear Information System (INIS)

    Slouma, S; Baccar, H

    2015-01-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system

  15. Improving efficiency of a regional stand alone bone bank.

    Science.gov (United States)

    Warnock, Jonathan M; Rowan, Clare H; Davidson, Helen; Millar, Ciara; McAlinden, M Gavan

    2016-03-01

    The introduction of a stand-alone Bone Bank in our Regional Orthopaedic Hospital has improved the availability of femoral head allograft. Benninger et al. (Bone Joint J 96-B:1307-1311, 2014), demonstrated their institutions bank to be cost effective despite a 30 % discard rate for harvested allograft. We sought to audit our own discard rates and subsequent cost-effectiveness of our bone bank. Donor recruitment. Before approaching a potential donor, our establishment's nurse specialists review their clinical notes and biochemical laboratory results, available on a regional Electronic Care Records. They view femoral head architecture on radiographs against set criteria, Patient Archive and Communication system (SECTRA, Sweden). In total 1383 femoral heads were harvested, 247 were discarded giving an overall rate of 17.9 %. The most common reasons for discard of harvested graft was a positive microbiology/bacteriology result, n = 96 (38.9 %). After a rise in discard rates in 2007, we have steadily reduced our discard rates since 2006/2007 (28.2 %), 2008/2009 (17 %), 2010/2011 (14.8 %), and finally to 10.3 % in 2012/2013. In the current financial year, our cost to harvest, test, store and release a femoral head is £ 610. With a structured donor recruitment process and unique pre-operative radiographic analysis we have successfully reduced our discard rates bi-annually making our bone bank increasingly cost-effective.

  16. The Stand-alone Heliostat; El Heliostato Autonomo

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Navajas, G.; Egea Gea, A. [Ciemat. Madrid (Spain)

    2000-07-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-m''2, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24 Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modern working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modern. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs.

  17. The Stand-alone Heliostat; El Heliostato Autonomo

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Navajas, G; Egea Gea, A [Ciemat. Madrid (Spain)

    2000-07-01

    The first Autonomous Heliostat has been developed by CIEMAT at PSA facilities in Almeria. This heliostat is an innovative approach to reducing the civil engineering work costs in heliostat fields of central tower plants. Channels, cables and other electric elements have been eliminated in the new heliostat. Thus, one 70-m''2, classical T glass/metal heliostat has been adapted to include all the new stand-alone concept components. A PV system is able to drive two sun-tracking DC motors between 5 and 24 Vdc, 0 and 15A. The heliostat communicates with the control room 400-m away by using a radio-modern working at 9600 baud. An anemometer, a wind switcher, light and ambient temperature sensors have been installed on the heliostat for self-protection decision-making. A PV panel integrated into the heliostat reflecting surface, eliminates cabling and other elements required for a conventional power supply. Communication lines between master control and local control have been replaced by radio-modern. Testing has validated the technical feasibility of the prototype and quantified the real consumption and efficiencies of new elements. The extra costs produced by the autonomous concepts are compared with the cost of civil work in conventional heliostat field. (Author) 8 refs.

  18. R and D into stand-alone PV systems for export

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The current status of photovoltaic (PV) technology is reviewed for systems to provide electricity where mains supplies are unavailable, known as stand-alone PV systems. Typical applications and experiences with installed stand-alone systems are described. Economic issues and barriers to the wide use of PV systems are also examined. (UK)

  19. Clinical outcome of stand-alone ALIF compared to posterior instrumentation for degenerative disc disease

    DEFF Research Database (Denmark)

    Udby, Peter M.; Bech-Azeddine, Rachid

    2015-01-01

    The objective of the article was to: a) present results from a case cohort pilot study comparing stand-alone ALIF and TLIF and, b) review the literature on studies comparing the clinical outcome of stand-alone ALIF with posterior instrumentation including TLIF or PLIF, in patients with disabling...... low back pain resulting from degenerative disc disease. ALIF surgery has previously been linked with certain high risk complications and unfavorable long term fusion results. Newer studies suggest that stand-alone ALIF can possibly be advantageous compared to other types of posterior instrumented...

  20. Procedures for Determining the Performance of Stand-Alone Photovoltaic Systems; TOPICAL

    International Nuclear Information System (INIS)

    DeBlasio, R.; Durand, S.; Hansen, R.; Hutchinson, P.; Kroposki, B.; McNutt, P.; Rosenthal, A.; Thomas, M.

    1999-01-01

    This document provides the procedures for determining the performance of stand-alone PV systems. The procedures in this document provide a common approach for evaluating whether a given PV system is suitable to perform the function for which it was designed and manufactured to accomplish, and whether it will provide adequate power to run the load. These procedures cover small stand-alone PV systems. They cover complete outdoor system testing. Test results are valid only for the system that is tested

  1. Posterior lumbar interbody fusion with stand-alone Trabecular Metal cages for repeatedly recurrent lumbar disc herniation and back pain

    NARCIS (Netherlands)

    Lequin, Michiel B.; Verbaan, Dagmar; Bouma, Gerrit J.

    2014-01-01

    Patients with recurrent sciatica due to repeated reherniation of the intervertebral disc carry a poor prognosis for recovery and create a large burden on society. There is no consensus about the best treatment for this patient group. The goal of this study was to evaluate the 12-month results of the

  2. Stand-alone photovoltaic systems in the Netherlands. Evaluation of the market introduction

    International Nuclear Information System (INIS)

    Cloin, J.; Van Dijk, A.L.; Westra, C.A.

    1999-08-01

    The policy followed for stand-alone PV systems in the Netherlands is evaluated for the period 1997-1998. The world-wide powerful growth of the PV industry is not being followed by the increase in volume of implemented stand-alone PV systems in the Netherlands. This leads to the question whether the Dutch policy to stimulate stand-alone PV systems is effective. Recommendations on the use of communication as a strategic instrument are given, including the drawing up of a marketing plan. Other recommendations include increased transparency in the application for subsidies and a pro-active role of the Netherlands Agency for Energy and the Environment (Novem) in the contact with relevant market parties. The increased focus on product development aimed at the environmental benefits and general reliability of PV systems is recommended. 38 refs

  3. Stand-alone wind system with Vanadium Redox Battery energy storage

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Barote, L.; Weissbach, R.

    2008-01-01

    Energy storage devices are required for power balance and power quality in stand alone wind energy systems. A Vanadium Redox Flow Battery (VRB) system has many features which make its integration with a stand-alone wind energy system attractive. This paper proposes the integration of a VRB system...... with a typical stand-alone wind energy system during wind speed variation as well as transient performance under variable load. The investigated system consists of a variable speed wind turbine with permanent magnet synchronous generator (PMSG), diode rectifier bridge, buck-boost converter, bidirectional charge...... controller, transformer, inverter, ac loads and VRB (to store a surplus of wind energy and to supply power during a wind power shortage). The main purpose is to supply domestic appliances through a single phase 230V, 50Hz inverter. Simulations are accomplished in order to validate the stability of the supply....

  4. Connecting embedded and stand-alone peer mentoring models to enhance student engagement

    Directory of Open Access Journals (Sweden)

    Rhys Cooper

    2018-03-01

    Full Text Available This paper outlines the Trident Student Mentoring Program that runs in the College of Engineering at Victoria University, Melbourne, Australia. The program offers both embedded and stand-alone models of peer mentoring services to the same cohort of first-year students. It shows that by forming strong links between these two types of peer mentoring models, the inherent challenges of both, such as low attendance rates in stand-alone models and short periods of peer to peer time in embedded models, are mitigated.

  5. Sensorless direct voltage control of the stand-alone brushless doubly-fed generator

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Xiong, Fei

    2017-01-01

    The conventional stand-alone brushless doubly-fed generator (BDFG) control strategies need the feedback from the rotor position or speed sensors, which can reduce system reliability and increase the cost and axial volume of the machine. In this paper, a sensorless direct voltage control (DVC) str......) strategy is presented for the stand-alone BDFG. The satisfactory dynamic performance is verified by experimental results under four kinds of typical operation conditions. Besides, the proposed control strategy is robust due to no generator parameters being required....

  6. Linguistic and Structural Analyses of Stand-Alone Literature Reviews: Seventy-Five Years of Change

    Science.gov (United States)

    Wright, Heidi Rachel

    2016-01-01

    The purpose of this dissertation is to offer a multifaceted overview of stand-alone literature reviews. These texts, literature reviews published unattached to research articles, have existed for centuries but remained largely unstudied by linguists. Thus, the goal of this project is to present these reviews' situational, grammatical, and…

  7. Assessment of Stand-Alone Displays for Time Management in a Creativity-Driven Learning Environment

    DEFF Research Database (Denmark)

    Frimodt-Møller, Søren

    2017-01-01

    This paper considers the pros and cons of stand-alone displays, analog (e.g. billboards, blackboards, whiteboards, large pieces of paper etc.) as well as digital (e.g. large shared screens, digital whiteboards or similar), as tools for time management processes in a creativity-driven learning...

  8. Stand-alone version of the 11kW Gaia wind turbine

    DEFF Research Database (Denmark)

    Bindner, H.; Rosas, P.A.C.; Teodorescu, R.

    2004-01-01

    This report describes the development of a stand-alone version of the 11kW Gaia wind turbine. Various possible configurations are investigated and a configuration using a back-to-back converter is chosen. A model is developed for controller design of thefast controllers of the unit. Controllers...... assessment and controller design a dynamic performance assessment model has been developed....

  9. A maximum power point tracking scheme for a 1kw stand-alone ...

    African Journals Online (AJOL)

    A maximum power point tracking scheme for a 1kw stand-alone solar energy based power supply. ... Nigerian Journal of Technology ... A method for efficiently maximizing the output power of a solar panel supplying a load or battery bus under ...

  10. Use of Super-Capacitor to Enhance Charging Performance of Stand-Alone Solar PV System

    KAUST Repository

    Huang, B. J.; Hsu, P. C.; Ho, P. Y

    2011-01-01

    Introduction: The battery charging performance in a stand-alone solar PV system affects the PV system efficiency and the load operating time. The New Energy Center of National Taiwan University has been devoted to the development of a PWM charging

  11. Environmental/Climatic Effect on Stand-Alone Solar Energy Supply ...

    African Journals Online (AJOL)

    This paper investigates the climatic eects and environmental variations on the performance of a stand-alone photovoltaic system. The eects of partial shading with dierent climate conditions and load resistance variations were examined. A survey of some of the work done in this eld of environmental eect on solar panel was ...

  12. 11kW stand alone wind turbine based on proven wind turbine

    DEFF Research Database (Denmark)

    Bindner, H.; Wodstrup, J.; Andersen, J.

    2004-01-01

    and enable control of frequency and voltage independently on both the grid side and the generator side. The prototype has been installed at Risø. The paper will present results from test runs of the system both operating stand-alone supplying a single load and in parallel operation with a diesel genset....

  13. Modelling of fluid-solid interaction using two stand-alone codes

    CSIR Research Space (South Africa)

    Grobler, Jan H

    2010-01-01

    Full Text Available A method is proposed for the modelling of fluid-solid interaction in applications where fluid forces dominate. Data are transferred between two stand-alone codes: a dedicated computational fluid dynamics (CFD) code capable of free surface modelling...

  14. Use of appliances in stand-alone PV power supply systems: problems and solutions. Task 3 use of photovoltaic power systems in stand-alone and island applications

    Energy Technology Data Exchange (ETDEWEB)

    Vallve, X.; Gafas, G. [IEA PVPS, Task 3 (Spain); Villoz, M. [IEA PVPS, Task 3 (Switzerland); Wilshaw, A. [IEA PVPS, Task 3 (United Kingdom); Jacquin, P. [IEA PVPS, Task 3 (France)

    2002-09-15

    In Stand-Alone Photovoltaic Systems (SAPV systems), special attention must be paid to the used appliances and loads. Inappropriate loads are very often the origin of PV system malfunction or failure. Start-up power peaks, or reactive power and harmonic distortion can cause system signal instability and protective devices will close the system down. A well-matched load together with a carefully selected choice of appliances can lead to significant savings in terms of reduced need for PV and electricity storage capacity. Conversely, inefficient appliances and processes, standby loads and inappropriate loads will increase the requirement for expensive PV and storage capacity. This paper presents a survey of real cases with load related problems in worldwide applications, their effect on quality and cost of the service and the solutions that were adopted and suggested alternative solutions. One of the main conclusions of the work is the importance to integrate the choice of the appliance while designing the SAPV system. (author)

  15. Hybrid Configuration of Darrieus and Savonius Rotors for Stand-alone Power Systems

    Science.gov (United States)

    Wakui, Tetsuya; Tanzawa, Yoshiaki; Hashizume, Takumi; Nagao, Toshio

    The suitable hybrid configuration of Darrieus lift-type and Savonius drag-type rotors for stand-alone wind turbine-generator systems is discussed using our dynamic simulation model. Two types of hybrid configurations are taken up: Type-A installs the Savonius rotor inside the Darrieus rotor and Type-B installs the Savonius rotor outside the Darrieus rotor. The computed results of the output characteristics and the dynamic behaviors of the system operated at the maximum power coefficient points show that Type-A, which has fine operating behavior to wind speed changes and can be compactly designed because of a shorter rotational shaft, is an effective way for self-controlled stand-alone small-scale systems.

  16. Stand-Alone Microgrid Inverter Controller Design for Nonlinear, Unbalanced Load with Output Transformer

    Directory of Open Access Journals (Sweden)

    Jae-Uk Lim

    2018-04-01

    Full Text Available This paper proposes a technique that compensates for unbalance and nonlinearity in microgrid inverters with power transformers operating in stand-alone mode. When a microgrid inverter is operating in stand-alone mode, providing high-quality power is very important. When an unbalanced, nonlinear load is connected, zero sequence current and negative sequence current occur, which leads to an unbalanced output voltage. This paper examines why the zero sequence component occurs differently depending on the structure of a three-phase transformer connected to the inverter output terminal, and it proposes a method for controlling the zero sequence component. It also uses a resonant controller to remove the harmonics that correspond to the negative sequence component and the nonlinear component. The proposed elements were verified by a Powersim (PSIM simulation.

  17. A Three-Port Topology Comparison for a Low Power Stand-Alone Photovoltaic System

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Three-port converter (TPC) topologies for renewable energy systems aim to provide higher efficiency and power density than conventional cascaded structures. This work proposes an analytical comparison of different TPC topologies for a photovoltaic LED lamp stand-alone system. A comparison using c...... component stress factor (CSF) is performed, which gives a quantitative measure of the performance of the converter. The candidate topologies are compared to each other according to a defined LED lighting strategy and a solar irradiation profile.......Three-port converter (TPC) topologies for renewable energy systems aim to provide higher efficiency and power density than conventional cascaded structures. This work proposes an analytical comparison of different TPC topologies for a photovoltaic LED lamp stand-alone system. A comparison using...

  18. Analysis and controller design for stand-alone VSIs in synchronous reference frame

    DEFF Research Database (Denmark)

    Ramezani, Malek; Li, Shuhui; Golestan, Saeed

    2017-01-01

    -by-step graphical analysis and design approach for a three-phase stand-alone VSI system in the dq reference frame, which provides a clear systematic decoupling process to design the inner- and outer-loop current and voltage controllers, respectively. The closed-loop d- and q-axis output impedances of the stand......-alone VSI system by considering the coupling effects between axes are also formulated, modelled, and evaluated. The study investigates how the decoupling and compensating terms added in the current and voltage controllers affect the dynamic performance and output dq impedances of the VSI system. Simulation...... and hardware results verify the effectiveness of the graphic design and analysis strategy....

  19. A new approach for sizing stand alone photovoltaic systems based in neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Hontoria, L.; Aguilera, J. [Universidad de Jaen, Dept. de Electronica, Jaen (Spain); Zufiria, P. [UPM Ciudad Universitaria, Dept. de Matematica Aplicada a las Tecnologias de la Informacion, Madrid (Spain)

    2005-02-01

    Several methods for sizing stand alone photovoltaic (pv) systems has been developed. The more simplistic are called intuitive methods. They are a useful tool for a first approach in sizing stand alone photovoltaic systems. Nevertheless they are very inaccurate. Analytical methods use equations to describe the pv system size as a function of reliability. These ones are more accurate than the previous ones but they are also not accurate enough for sizing of high reliability. In a third group there are methods which use system simulations. These ones are called numerical methods. Many of the analytical methods employ the concept of reliability of the system or the complementary term: loss of load probability (LOLP). In this paper an improvement for obtaining LOLP curves based on the neural network called Multilayer Perceptron (MLP) is presented. A unique MLP for many locations of Spain has been trained and after the training, the MLP is able to generate LOLP curves for any value and location. (Author)

  20. Minimum cost solution of wind–photovoltaic based stand-alone power systems for remote consumers

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Zafirakis, D.; Kavadias, K.

    2012-01-01

    Renewable energy sources (RES) based stand-alone systems employing either wind or solar power and energy storage comprise a reliable energy alternative, on top of conventional diesel-electric generator sets, commonly used by remote consumers. However, such systems usually imply the need for oversizing and considerable energy storage requirements leading to relatively high costs. On the other hand, hybrid configurations that may exploit both wind and solar potential of a given area may considerably reduce energy storage capacity and improve the economic performance of the system. In this context, an integrated techno-economic methodology for the evaluation of hybrid wind–photovoltaic stand-alone power systems is currently developed, aiming at the designation of optimum configurations for a typical remote consumer, using economic performance criteria. For the problem investigation, the developed evaluation model is applied to four representative areas of the Greek territory with different wind potential characteristics in order to obtain optimum configurations on the basis of minimum initial investment, 10-year and 20-year total cost. According to the results obtained, the proposed solution is favorably compared with all other stand-alone energy alternatives, reflecting the ability of hybrid systems to adjust even in areas where the local RES potential is not necessarily of high quality. - Highlights: ► Wind- and PV-stand alone systems often imply use of extreme battery capacity. ► Hybrid wind–PV systems may reduce energy storage requirements and associated costs. ► An optimization methodology is developed, based on economic performance criteria. ► Methodology is applied to four Greek regions of different wind potential. ► Results obtained reflect the hybrid solution's advantages over other alternatives.

  1. Secure stand alone positive personnel identity verification system (SSA-PPIV)

    International Nuclear Information System (INIS)

    Merillat, P.D.

    1979-03-01

    The properties of a secure stand-alone positive personnel identity verification system are detailed. The system is designed to operate without the aid of a central computing facility and the verification function is performed in the absence of security personnel. Security is primarily achieved by means of data encryption on a magnetic stripe badge. Several operational configurations are discussed. Advantages and disadvantages of this system compared to a central computer driven system are detailed

  2. MOSFET Loss Evaluation for a Low-Power Stand-Alone Photovoltaic-LED System

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Knott, Arnold; Andersen, Michael A. E.

    2015-01-01

    This paper presents a performance evaluation and comparison of state-of-the-art low voltage Si MOSFETs for a stand-alone photovoltaic-LED Light to Light (LtL) system. The complete system is formed by two cascaded converters that will be optimized for a determined solar irradiation and LED...... illumination profiles. The comparison is performed based on dynamic characterization and evaluation of the devices energy loss at different current levels....

  3. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    OpenAIRE

    Suresh Baral; Kyung Chun Kim

    2015-01-01

    The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC) water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal ef...

  4. Methodology for the design of a stand-alone photovoltaic power supply

    OpenAIRE

    López Seguel, Julio; Seleme Junior, Seleme Isaac; Donoso-Garcia, Pedro F; Ferreira Morais, Lenin Martins; Cabaleiro Cortizo, Porfirio; Severo Mendes, Marcos A

    2013-01-01

    This paper presents a complete methodology for the design of an autonomous photovoltaic system to maximize the use of solar energy. It is a method that prioritizes the best cost-effective choice at every step of the project. In order to ensure the proper use and extended battery life time, a control strategy for charging the batteries is proposed. Experimental results are provided for a stand-alone photovoltaic system with low electrical power, intended primarily for the illumination and basi...

  5. Modeling, Design and Simulation of Stand-Alone Photovoltaic Power Systems with Battery Storage

    Directory of Open Access Journals (Sweden)

    Abd Essalam BADOUD

    2013-06-01

    Full Text Available Stand alone renewable energy based on photovoltaic systems accompanied with battery storage system are beginning to play an important role over the world to supply power to remote areas. The objective of the study reported in this paper is to elaborate and design a bond graphs model for sizing stand-alone domestic solar photovoltaic electricity systems and simulating the performance of the systems in a tropical climate. The systems modelled consist of an array of PV modules, a lead-acid battery, and a number of direct current appliances. This paper proposes the combination of lead acid battery system with a typical stand alone photovoltaic energy system under variable loads. The main activities of this work purpose to establish library graphical models for each individual component of standalone photovoltaic system. Control strategy has been considered to achieve permanent power supply to the load via photovoltaic/battery based on the power available from the sun. The complete model was simulated under two testing including sunny and cloudy conditions. Simulation of the system using Symbols software was performed and the results of simulation show the superior stable control system and high efficiency. These results have been contrasted with real measured data from a measurement campaign plant carried on electrical engineering laboratory of Grenoble using various interconnection schemes are presented.

  6. Structure Optimization of Stand-Alone Renewable Power Systems Based on Multi Object Function

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Cho

    2016-08-01

    Full Text Available This paper presents a methodology for the size optimization of a stand-alone hybrid PV/wind/diesel/battery system while considering the following factors: total annual cost (TAC, loss of power supply probability (LPSP, and the fuel cost of the diesel generator required by the user. A new optimization algorithm and an object function (including a penalty method are also proposed; these assist with designing the best structure for a hybrid system satisfying the constraints. In hybrid energy system sources such as photovoltaic (PV, wind, diesel, and energy storage devices are connected as an electrical load supply. Because the power produced by PV and wind turbine sources is dependent on the variation of the resources (sun and wind and the load demand fluctuates, such a hybrid system must be able to satisfy the load requirements at any time and store the excess energy for use in deficit conditions. Therefore, reliability and cost are the two main criteria when designing a stand-alone hybrid system. Moreover, the operation of a diesel generator is important to achieve greater reliability. In this paper, TAC, LPSP, and the fuel cost of the diesel generator are considered as the objective variables and a hybrid teaching–learning-based optimization algorithm is proposed and used to choose the best structure of a stand-alone hybrid PV/wind/diesel/battery system. Simulation results from MATLAB support the effectiveness of the proposed method and confirm that it is more efficient than conventional methods.

  7. Optimization of stand-alone photovoltaic systems with hydrogen storage for total energy self-sufficiency

    Energy Technology Data Exchange (ETDEWEB)

    Lund, P D [Helsinki Univ. of Technology, Espoo (Finland). Dept. of Technical Physics

    1991-01-01

    A new method for optimization of stand-alone photovoltaic-hydrogen energy systems is presented. The methodology gives the optimum values for the solar array and hydrogen storage size for any given system configuration and geographical site. Sensitivity analyses have been performed to study the effect of subsystem efficiencies on the total system performance and sizing, and also to identify possibilities for further improvements. Optimum system configurations have also been derived. The results indicate that a solar-hydrogen energy system is a very promising potential alternative for low power applications requiring a total electricity self-sufficiency. (Author).

  8. A Simple Sizing Algorithm for Stand-Alone PV/Wind/Battery Hybrid Microgrids

    Directory of Open Access Journals (Sweden)

    Jing Li

    2012-12-01

    Full Text Available In this paper, we develop a simple algorithm to determine the required number of generating units of wind-turbine generator and photovoltaic array, and the associated storage capacity for stand-alone hybrid microgrid. The algorithm is based on the observation that the state of charge of battery should be periodically invariant. The optimal sizing of hybrid microgrid is given in the sense that the life cycle cost of system is minimized while the given load power demand can be satisfied without load rejection. We also report a case study to show the efficacy of the developed algorithm.

  9. Lossy Data Aggregation with Network Coding in Stand-Alone Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Madsen, Tatiana Kozlova

    2011-01-01

    in chemical plants, etc. Given resource constrained operation of a sensor network where the nodes are battery powered and buffer sizes are limited, efficient methods for in-network data storage abd it subsequent fast and reliable transmission to a gateway is desirable. To save scarse resources and to prolong......This work focuses on a special type of wireless sensor networks (WSNs) that we refer to as a stand alone network. These netwoks operate in harsh and extreme environments where data collection is done only occasionally. Typical examples include habitat monitoring systems, monitoring systems...

  10. Boost converter with combined control loop for a stand-alone photovoltaic battery charge system

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Knott, Arnold; Thomsen, Ole Cornelius

    2013-01-01

    frequency avoids perturbations in the load being propagated to the photovoltaic panel and thus deviating the operating point. Linearization of the photovoltaic panel and converter state-space modeling is performed. In order to achieve stable operation under all operating conditions, the photovoltaic panel......The converter control scheme plays an important role in the performance of maximum power point tracking (MPPT) algorithms. In this paper, an input voltage control with double loop for a stand-alone photovoltaic system is designed and tested. The inner current control loop with high crossover...

  11. System design optimization for stand-alone photovoltaic systems sizing by using superstructure model

    International Nuclear Information System (INIS)

    Azau, M A M; Jaafar, S; Samsudin, K

    2013-01-01

    Although the photovoltaic (PV) systems have been increasingly installed as an alternative and renewable green power generation, the initial set up cost, maintenance cost and equipment mismatch are some of the key issues that slows down the installation in small household. This paper presents the design optimization of stand-alone photovoltaic systems using superstructure model where all possible types of technology of the equipment are captured and life cycle cost analysis is formulated as a mixed integer programming (MIP). A model for investment planning of power generation and long-term decision model are developed in order to help the system engineer to build a cost effective system.

  12. Development of a microprocessor controller for stand-alone photovoltaic power systems

    Science.gov (United States)

    Millner, A. R.; Kaufman, D. L.

    1984-01-01

    A controller for stand-alone photovoltaic systems has been developed using a low power CMOS microprocessor. It performs battery state of charge estimation, array control, load management, instrumentation, automatic testing, and communications functions. Array control options are sequential subarray switching and maximum power control. A calculator keypad and LCD display provides manual control, fault diagnosis and digital multimeter functions. An RS-232 port provides data logging or remote control capability. A prototype 5 kW unit has been built and tested successfully. The controller is expected to be useful in village photovoltaic power systems, large solar water pumping installations, and other battery management applications.

  13. Design, building and testing of a stand alone fuel cell hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Segura, F.; Duran, E.; Andujar, J.M. [Department of Electronic, Computer Science and Automatic Engineering, University of Huelva (Spain)

    2009-08-01

    This paper designs, sizes, builds and tests a stand alone fuel cell hybrid system made up of a fuel cell stack and a battery bank. This system has been sized to supply a typical telecommunication load profile, but moreover, the system can supply other profiles. For this purpose, a modular low cost electronic load bank has been designed and built. This load bank allows the power demand to be chosen by selecting different solid state relays. Moreover, a virtual instrument based on NI Labview {sup registered} has been designed to select the load power demand from the computer. (author)

  14. Design and Operation Studies of A Stand-Alone PV Generation System

    DEFF Research Database (Denmark)

    Hu, Yanting; Chen, Zhe; Zhang, Donglai

    2013-01-01

    This paper discusses the modeling, design and operation of a PV powered stand-alone system, which includes a PV array, a battery bank, power electronic converters and the associated control system. The design considerations are analyzed and a design platform is presented. Furthermore the operation...... modes of the system are described. A power electronic system with the associated control scheme has been proposed and simulation models have been developed. Simulation studies have been conducted on an example system; the results have demonstrated the effectiveness of the presented methods....

  15. State Feedback Decoupling with In-Loop Lead Compensator in Stand-Alone VSIs

    DEFF Research Database (Denmark)

    Federico, de Bosio; Pastorelli, Michele; de Sousa Ribeiro, Luiz Antonio

    2016-01-01

    The performance of current and voltage regulators during transients and steady-state is of primary concern for power converters intended for stand-alone applications. Dynamics performance and command tracking capability are enhanced by actively decoupling the controlled states variables. To further...... widen the current loop bandwidth while still preserving a well-damped system a lead compensator structure on the forward loop is proposed. A 3 kHz bandwidth with 0.707 damping factor is achieved for the inner current controller. Accordingly, also the voltage regulator bandwidth can be widen, thus...

  16. Information systems for the materials management department: stand-alone and enterprise resource planning systems.

    Science.gov (United States)

    2005-03-01

    Materials management information systems (MMISs) incorporate information tools that hospitals can use to automate certain business processes, increase staff compliance with these processes, and identify opportunities for cost savings. Recently, there has been a push by hospital administration to purchase enterprise resource planning (ERP) systems, information systems that promise to integrate many more facets of healthcare business. We offer this article to help materials managers, administrators, and others involved with information system selection understand the changes that have taken place in materials management information systems, decide whether they need a new system and, if so, whether a stand-alone MMIS or an ERP system will be the best choice.

  17. Simulation of stand alone PV systems; Dokuritsugata taiyoko hatsuden system no simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, I.; Sakuta, K. [Electrotechnical Laboratory, Tsukuba (Japan); Oshiro, T. [Japan Quality Assurance Organization, Tokyo (Japan); Kurokawa, K. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1997-11-25

    Studies are performed to develop a simulation program for a stand-alone photovoltaic power generation system equipped with a lead acid battery. In this stand-alone photovoltaic power generation system, the load is connected in shunt with the solar cell array output through the intermediary of a lead acid battery and inverter. The program is a model in which the solar cell model is built taking parallel resistance into account, and the temperature-dependence of the constants is described using approximations experimentally obtained by Solar Techno Center of JQA (Japan Quality Assurance Organization), Hamamatsu. Insolation data for the model is described using METPV compiled by Japan Weather Association, and load data is described using data actually measured at Shizuoka. This program is compared with the data of operation at Hamamatsu, and the result is almost satisfactory. Simulations are conducted at five typical locations in Japan using this program, and it is found that the array load matching correction factor is dependent on seasonal changes rather than locality, that the battery contribution rate does not change much throughout the year, and that it is not dependent on locality. 5 refs., 7 figs., 3 tabs.

  18. Modified Chaos Particle Swarm Optimization-Based Optimized Operation Model for Stand-Alone CCHP Microgrid

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-07-01

    Full Text Available The optimized dispatch of different distributed generations (DGs in stand-alone microgrid (MG is of great significance to the operation’s reliability and economy, especially for energy crisis and environmental pollution. Based on controllable load (CL and combined cooling-heating-power (CCHP model of micro-gas turbine (MT, a multi-objective optimization model with relevant constraints to optimize the generation cost, load cut compensation and environmental benefit is proposed in this paper. The MG studied in this paper consists of photovoltaic (PV, wind turbine (WT, fuel cell (FC, diesel engine (DE, MT and energy storage (ES. Four typical scenarios were designed according to different day types (work day or weekend and weather conditions (sunny or rainy in view of the uncertainty of renewable energy in variable situations and load fluctuation. A modified dispatch strategy for CCHP is presented to further improve the operation economy without reducing the consumers’ comfort feeling. Chaotic optimization and elite retention strategy are introduced into basic particle swarm optimization (PSO to propose modified chaos particle swarm optimization (MCPSO whose search capability and convergence speed are improved greatly. Simulation results validate the correctness of the proposed model and the effectiveness of MCPSO algorithm in the optimized operation application of stand-alone MG.

  19. Design of a Stand-Alone Photovoltaic Model for Home Lightings and Clean Environment

    Energy Technology Data Exchange (ETDEWEB)

    Ani, Vincent Anayochukwu, E-mail: vincent_ani@yahoo.com [Department of Electronic Engineering, University of Nigeria, Nsukka (Nigeria)

    2016-01-11

    This paper gives a well-documented health risk of fuel-based lighting (kerosene lamps and fuel-powered generators) and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs) using two different battery types (Rolls Surrette 6CS25PS and Hoppecke 10 OpzS 1000) on; (i) judicious power consumption, (ii) normal power consumption, and (iii) excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedures were used to demonstrate the best solution (reliability at the lowest lifecycle cost). Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with EEL options (judicious power consumption, normal power consumption, and excess power consumption).

  20. Design of Stand-Alone Hybrid Power Generation System at Brumbun Beach Tulungagung East Java

    Science.gov (United States)

    Rahmat, A. N.; Hidayat, M. N.; Ronilaya, F.; Setiawan, A.

    2018-04-01

    Indonesian government insists to optimize the use of renewable energy resources in electricity generation. One of the efforts is launching Independent Energy Village plan. This program aims to fulfill the need of electricity for isolated or remote villages in Indonesia. In order to support the penetration of renewable energy resources in electricity generation, a hybrid power generation system is developed. The simulation in this research is based on the availability of renewable energy resources in Brumbun beach, Tulungagung, East Java. Initially, the electricity was supplied through stand-alone electricity generations which are installed at each house. Hence, the use of electricity between 5 p.m. – 9 p.m. requires high operational costs. Based on the problem above, this research is conducted to design a stand-alone hybrid electricity generation system, which may consist of diesel, wind, and photovoltaic. The design is done by using HOMER software to optimize the use of electricity from renewable resources and to reduce the operation of diesel generation. The combination of renewable energy resources in electricity generation resulted in NPC of 44.680, COE of 0,268, and CO2 emissions of 0,038 % much lower than the use of diesel generator only.

  1. Fuzzy logic control of stand-alone photovoltaic system with battery storage

    Science.gov (United States)

    Lalouni, S.; Rekioua, D.; Rekioua, T.; Matagne, E.

    Photovoltaic energy has nowadays an increased importance in electrical power applications, since it is considered as an essentially inexhaustible and broadly available energy resource. However, the output power provided via the photovoltaic conversion process depends on solar irradiation and temperature. Therefore, to maximize the efficiency of the photovoltaic energy system, it is necessary to track the maximum power point of the PV array. The present paper proposes a maximum power point tracker (MPPT) method, based on fuzzy logic controller (FLC), applied to a stand-alone photovoltaic system. It uses a sampling measure of the PV array power and voltage then determines an optimal increment required to have the optimal operating voltage which permits maximum power tracking. This method carries high accuracy around the optimum point when compared to the conventional one. The stand-alone photovoltaic system used in this paper includes two bi-directional DC/DC converters and a lead-acid battery bank to overcome the scare periods. One converter works as an MPP tracker, while the other regulates the batteries state of charge and compensates the power deficit to provide a continuous delivery of energy to the load. The Obtained simulation results show the effectiveness of the proposed fuzzy logic controller.

  2. A sizing method for stand-alone PV installations with variable demand

    Energy Technology Data Exchange (ETDEWEB)

    Posadillo, R. [Grupo de Investigacion en Energias y Recursos Renovables, Dpto. de Fisica Aplicada, E.P.S., Universidad de Cordoba, Avda. Menendez Pidal s/n, 14004 Cordoba (Spain); Lopez Luque, R. [Grupo de Investigacion de Fisica Para las Energias y Recursos Renovables, Dpto. de Fisica Aplicada, Edificio C2 Campus de Rabanales, 14071 Cordoba (Spain)

    2008-05-15

    The practical applicability of the considerations made in a previous paper to characterize energy balances in stand-alone photovoltaic systems (SAPV) is presented. Given that energy balances were characterized based on monthly estimations, the method is appropriate for sizing installations with variable monthly demands and variable monthly panel tilt (for seasonal estimations). The method presented is original in that it is the only method proposed for this type of demand. The method is based on the rational utilization of daily solar radiation distribution functions. When exact mathematical expressions are not available, approximate empirical expressions can be used. The more precise the statistical characterization of the solar radiation on the receiver module, the more precise the sizing method given that the characterization will solely depend on the distribution function of the daily global irradiation on the tilted surface H{sub g{beta}}{sub i}. This method, like previous ones, uses the concept of loss of load probability (LLP) as a parameter to characterize system design and includes information on the standard deviation of this parameter ({sigma}{sub LLP}) as well as two new parameters: annual number of system failures (f) and the standard deviation of annual number of system failures ({sigma}{sub f}). This paper therefore provides an analytical method for evaluating and sizing stand-alone PV systems with variable monthly demand and panel inclination. The sizing method has also been applied in a practical manner. (author)

  3. Design of a Stand-Alone Photovoltaic (PV Models for Home Lightings and Clean Environment

    Directory of Open Access Journals (Sweden)

    Vincent Anayochukwu Ani

    2016-01-01

    Full Text Available This paper gives a well-documented health risks of fuel-based lighting (kerosene lamps and fuel-powered generators and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs using two different battery types (Rolls Surrette 6CS25PS and hoppecke 10 OpzS 1000 on; i judicious power consumption, ii normal power consumption, iii excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedure were used to demonstrate the best solution (reliability at the lowest lifecycle cost. Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with energy efficient lighting options (judicious power consumption, normal power consumption, and excess power consumption.

  4. International market assessment of stand-alone photovoltaic power systems for cottage industry applications

    Science.gov (United States)

    Philippi, T. M.

    1981-01-01

    The final result of an international assessment of the market for stand-alone photovoltaic systems in cottage industry applications is reported. Nonindustrialized countries without centrally planned economies were considered. Cottage industries were defined as small rural manufacturers, employing less than 50 people, producing consumer and simple products. The data to support this analysis were obtained from secondary and expert sources in the U.S. and in-country field investigations of the Philippines and Mexico. The near-term market for photovoltaics for rural cottage industry applications appears to be limited to demonstration projects and pilot programs, based on an in-depth study of the nature of cottage industry, its role in the rural economy, the electric energy requirements of cottage industry, and a financial analysis of stand-alone photovoltaic systems as compared to their most viable competitor, diesel driven generators. Photovoltaics are shown to be a better long-term option only for very low power requirements. Some of these uses would include clay mixers, grinders, centrifuges, lathes, power saws and lighting of a workshop.

  5. Coordination Control Strategy for AC/DC Hybrid Microgrids in Stand-Alone Mode

    Directory of Open Access Journals (Sweden)

    Dwi Riana Aryani

    2016-06-01

    Full Text Available Interest in DC microgrids is rapidly increasing along with the improvement of DC power technology because of its advantages. To support the integration process of DC microgrids with the existing AC utility grids, the form of hybrid AC/DC microgrids is considered for higher power conversion efficiency, lower component cost and better power quality. In the system, AC and DC portions are connected through interlink bidirectional AC/DC converters (IC with a proper control system and power management. In the stand-alone operation mode of AC/DC hybrid microgrids, the control of power injection through the IC is crucial in order to maintain the system security. This paper mainly deals with a coordination control strategy of IC and a battery energy storage system (BESS converter under stand-alone operation. A coordinated control strategy for the IC, which considers the state of charge (SOC level of BESS and the load shedding scheme as the last resort, is proposed to obtain better power sharing between AC and DC subgrids. The scheme will be tested with a hybrid AC/DC microgrid, using the tool of the PSCAD/EMTDC software.

  6. International market assessment of stand-alone photovoltaic power systems for cottage industry applications

    Science.gov (United States)

    Philippi, T. M.

    1981-11-01

    The final result of an international assessment of the market for stand-alone photovoltaic systems in cottage industry applications is reported. Nonindustrialized countries without centrally planned economies were considered. Cottage industries were defined as small rural manufacturers, employing less than 50 people, producing consumer and simple products. The data to support this analysis were obtained from secondary and expert sources in the U.S. and in-country field investigations of the Philippines and Mexico. The near-term market for photovoltaics for rural cottage industry applications appears to be limited to demonstration projects and pilot programs, based on an in-depth study of the nature of cottage industry, its role in the rural economy, the electric energy requirements of cottage industry, and a financial analysis of stand-alone photovoltaic systems as compared to their most viable competitor, diesel driven generators. Photovoltaics are shown to be a better long-term option only for very low power requirements. Some of these uses would include clay mixers, grinders, centrifuges, lathes, power saws and lighting of a workshop.

  7. Feasibility and Optimal Design of a Stand-Alone Photovoltaic Energy System for the Orphanage

    Directory of Open Access Journals (Sweden)

    Vincent Anayochukwu Ani

    2014-01-01

    Full Text Available Access to electricity can have a positive psychological impact through a lessening of the sense of exclusion, and vulnerability often felt by the orphanages. This paper presented the simulation and optimization study of a stand-alone photovoltaic power system that produced the desired power needs of an orphanage. Solar resources for the design of the system were obtained from the National Aeronautics and Space Administration (NASA Surface Meteorology and Solar Energy website at a location of 6°51′N latitude and 7°35′E longitude, with annual average solar radiation of 4.92 kWh/m2/d. This study is based on modeling, simulation, and optimization of energy system in the orphanage. The patterns of load consumption within the orphanage were studied and suitably modeled for optimization. Hybrid Optimization Model for Electric Renewables (HOMER software was used to analyze and design the proposed stand-alone photovoltaic power system model. The model was designed to provide an optimal system configuration based on an hour-by-hour data for energy availability and demands. A detailed design, description, and expected performance of the system were presented in this paper.

  8. Robust Power Management Control for Stand-Alone Hybrid Power Generation System

    International Nuclear Information System (INIS)

    Kamal, Elkhatib; Adouane, Lounis; Aitouche, Abdel; Mohammed, Walaa

    2017-01-01

    This paper presents a new robust fuzzy control of energy management strategy for the stand-alone hybrid power systems. It consists of two levels named centralized fuzzy supervisory control which generates the power references for each decentralized robust fuzzy control. Hybrid power systems comprises: a photovoltaic panel and wind turbine as renewable sources, a micro turbine generator and a battery storage system. The proposed control strategy is able to satisfy the load requirements based on a fuzzy supervisor controller and manage power flows between the different energy sources and the storage unit by respecting the state of charge and the variation of wind speed and irradiance. Centralized controller is designed based on If-Then fuzzy rules to manage and optimize the hybrid power system production by generating the reference power for photovoltaic panel and wind turbine. Decentralized controller is based on the Takagi-Sugeno fuzzy model and permits us to stabilize each photovoltaic panel and wind turbine in presence of disturbances and parametric uncertainties and to optimize the tracking reference which is given by the centralized controller level. The sufficient conditions stability are formulated in the format of linear matrix inequalities using the Lyapunov stability theory. The effectiveness of the proposed Strategy is finally demonstrated through a SAHPS (stand-alone hybrid power systems) to illustrate the effectiveness of the overall proposed method. (paper)

  9. Design of a Stand-Alone Photovoltaic Model for Home Lightings and Clean Environment

    International Nuclear Information System (INIS)

    Ani, Vincent Anayochukwu

    2016-01-01

    This paper gives a well-documented health risk of fuel-based lighting (kerosene lamps and fuel-powered generators) and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs) using two different battery types (Rolls Surrette 6CS25PS and Hoppecke 10 OpzS 1000) on; (i) judicious power consumption, (ii) normal power consumption, and (iii) excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedures were used to demonstrate the best solution (reliability at the lowest lifecycle cost). Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with EEL options (judicious power consumption, normal power consumption, and excess power consumption).

  10. Input of biomass in stand-alone small-scale installations for power generation. Calculation of the financial gap

    International Nuclear Information System (INIS)

    Van Tilburg, X.; De Vries, H.J.; Pfeiffer, A.E.; Beekes, M.; Cleijne, J.W.

    2005-09-01

    A number of new initiatives in which bio-oil is used in stand-alone plants for power generation has been reviewed. The question to be answered is whether the reference case for stand alone biomass projects based on burning of wood chips can still be considered representative for the costs and benefits in this category. ECN, in cooperation with KEMA, have determined the financial gap between the costs and benefits of projects in which bio-oil is used in stand alone plants for power generation. The ranges and reference case for bio-oil in stand alone applications show that these projects have a substantially lower financial gap than the current reference case based on wood chips [nl

  11. Charactrization of a Li-ion battery based stand-alone a-Si photovoltaic system

    International Nuclear Information System (INIS)

    Hamid Vishkasougheh, Mehdi; Tunaboylu, Bahadir

    2014-01-01

    Highlights: • An Li-ion battery based stand-alone a-Si PV was designed. The system composed of three a-Si panels with an efficiency of 7% and 40 cells of LFP batteries. • Effects of solar radiation and environmental temperature for three cities, Istanbul, Ankara, and Adana, have been investigated on a-Si panels. • Using transition formulas BSPV outputs are predictable for any location out of standard test condition. - Abstract: The number of photovoltaic (PV) system installations is increasing rapidly. As more people learn about this versatile and often cost-effective power option, this trend will accelerate. This document presents a recommended design for a battery based stand-alone photovoltaic system (BSPV). BSPV system has the ability to be applied in different areas, including warning signals, lighting, refrigeration, communication, residential water pumping, remote sensing, and cathodic protection. The presented calculation method gives a proper idea for a system sizing technique. Based on application load, different scenarios are possible for designing a BSPV system. In this study, a battery based stand-alone system was designed. The electricity generation part is three a-Si panels, which are connected in parallel, and for the storage part LFP (lithium iron phosphate) battery was used. The high power LFP battery packs are 40 cells each 8S5P (configured 8 series 5 parallel). Each individual pack weighs 0.5 kg and is 25.6 V. In order to evaluate the efficiency of a-Si panels with respect to the temperature and the solar irradiation, cities of Istanbul, Ankara and Adana in Turkey were selected. Temperature and solar irradiation were gathered from reliable sources and by using translation equations, current and voltage output of panels were calculated. As a result of these calculations, current and energy outputs were computed by considering an average efficient solar irradiation time value per day in Turkey. The calculated power values were inserted to a

  12. Charactrization of a Li-ion battery based stand-alone a-Si photovoltaic system

    Energy Technology Data Exchange (ETDEWEB)

    Hamid Vishkasougheh, Mehdi, E-mail: mehdi.hamid2@gmail.com [Istanbul Sehir University, Kubakisi Caddesi, No: 27, Altunizade, Uskudar, Istanbul 34662 (Turkey); Tunaboylu, Bahadir [Istanbul Sehir University, Kubakisi Caddesi, No: 27, Altunizade, Uskudar, Istanbul 34662 (Turkey); Marmara Research Center, Materials Institute, PO Box 21, Gebze, Kocaeli 41470 (Turkey)

    2014-11-01

    Highlights: • An Li-ion battery based stand-alone a-Si PV was designed. The system composed of three a-Si panels with an efficiency of 7% and 40 cells of LFP batteries. • Effects of solar radiation and environmental temperature for three cities, Istanbul, Ankara, and Adana, have been investigated on a-Si panels. • Using transition formulas BSPV outputs are predictable for any location out of standard test condition. - Abstract: The number of photovoltaic (PV) system installations is increasing rapidly. As more people learn about this versatile and often cost-effective power option, this trend will accelerate. This document presents a recommended design for a battery based stand-alone photovoltaic system (BSPV). BSPV system has the ability to be applied in different areas, including warning signals, lighting, refrigeration, communication, residential water pumping, remote sensing, and cathodic protection. The presented calculation method gives a proper idea for a system sizing technique. Based on application load, different scenarios are possible for designing a BSPV system. In this study, a battery based stand-alone system was designed. The electricity generation part is three a-Si panels, which are connected in parallel, and for the storage part LFP (lithium iron phosphate) battery was used. The high power LFP battery packs are 40 cells each 8S5P (configured 8 series 5 parallel). Each individual pack weighs 0.5 kg and is 25.6 V. In order to evaluate the efficiency of a-Si panels with respect to the temperature and the solar irradiation, cities of Istanbul, Ankara and Adana in Turkey were selected. Temperature and solar irradiation were gathered from reliable sources and by using translation equations, current and voltage output of panels were calculated. As a result of these calculations, current and energy outputs were computed by considering an average efficient solar irradiation time value per day in Turkey. The calculated power values were inserted to a

  13. Loss-of-load probabilities for stand-alone photovoltaic systems

    International Nuclear Information System (INIS)

    Klein, S.A.; Beckman, W.A.

    1989-01-01

    A general method is presented for estimating the loss-of-load probability of stand-alone photovoltaic systems. The method was developed by correlating simulation results. The simulations were driven with synthetic radiation sequences having the same statistical significance as available historical data. The methods assumes a constant nighttime load and accounts for the distribution and persistence in daily solar radiation data. It is shown that the 10 year average performance of systems having loss-of-load probabilities less than about 0.01 can vary greatly from one ten year period to the next and thereby cannot be considered realistic performance estimates of a system during its lifetime. (author). 26 refs, 15 figs, 4 tabs

  14. Stand-alone version of the 11kW Gaia wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Bindner, H.; Rosas, P.A.C.; Teodorescu, R.; Blaabjerg, F.

    2004-09-15

    This report describes the development of a stand-alone version of the 11kW Gaia wind turbine. Various possible configurations are investigated and a configuration using a back-to-back converter is chosen. A model is developed for controller design of the fast controllers of the unit. Controllers are designed and a prototype is built for testing. The report documents the performance of the prototype through measurements done on the full scale prototype installed in a test facility where it has been tested both as a standalone unit and in parallel with a diesel genset. For system wide power quality assessment and controller design a dynamic performance assessment model has been developed. (au)

  15. Size optimization of stand-alone photovoltaic (PV) room air conditioners

    International Nuclear Information System (INIS)

    Chen, Chien-Wei; Zahedi, A.

    2006-01-01

    Sizing of a stand-alone PV system determines the main cost of the system. PV electricity cost is determined by the amount of solar energy received, hence the actual climate and weather conditions such as solar irradiance and ambient temperature affect the size required and cost of the system. Air conditioning demand also depends on the weather conditions. Therefore, sizing a PV powered air conditioner must consider the characteristics of local climate and temperature. In this paper, sizing procedures and special considerations for air conditioning under Melbourne's climatic conditions is presented. The reliability of various PV-battery size combinations is simulated by MATLAB. As a result, excellent system performance can be predicated.(Author)

  16. An Analysis of Stand-alone GPS Quality and Simulated GNSS Quality for Road Pricing

    DEFF Research Database (Denmark)

    Zabic, Martina; Nielsen, Otto Anker

    2006-01-01

    Use of GPS for road pricing has often been suggested as the way of creating more efficient charging strategies than existing systems based on cordon lines or time use. In Denmark, Copenhagen participated with the AKTA project in the PRoGRESS programme, sponsored by the EU. The major part...... of the AKTA project was to equip 500 cars with GPS receivers. The paper presents the methods and results from a study of GPS quality in relation to road pricing in a dense urban area. The collected data from 500 cars over a two-year period in the Copenhagen region was analyzed in order to determine whether...... the stand alone GPS quality and reliability is adequate for implementation of an operational road pricing system in Copenhagen. The results from the analysis show that the satellite availability in Copenhagen is not sufficient to form the basis for a reliable operational road pricing system. The narrow...

  17. Integrated Three-Port DC-DC Converter for Photovoltaic (PV) Battery Stand-alone Systems

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2016-01-01

    of solar energy. Moreover, a novel transformer configuration enables variable turns ratio controlled by the phase between the two current excitations subjected to the primary windings, allowing a wider input/output range. 1 kW experimental prototype has been built to demonstrate a wellmanaged power flow......Several power sources such as PV solar arrays and battery are often used to manage the power flow for a photovoltaic (PV) based stand-alone power system due to the fluctuation nature of solar energy resource, and deliver a continuous power to the users in an appropriate form. Traditionally, three...... different single-input single-output (SISO) dc/dc converters would have been used. To reduce the cost and improve the power density of the system, an integrated three-port isolated dc/dc converter is proposed in this paper. It can realize all functions of the energy delivery due to the fluctuation nature...

  18. Study of Stand-Alone Microgrid under Condition of Faults on Distribution Line

    Science.gov (United States)

    Malla, S. G.; Bhende, C. N.

    2014-10-01

    The behavior of stand-alone microgrid is analyzed under the condition of faults on distribution feeders. During fault since battery is not able to maintain dc-link voltage within limit, the resistive dump load control is presented to do so. An inverter control is proposed to maintain balanced voltages at PCC under the unbalanced load condition and to reduce voltage unbalance factor (VUF) at load points. The proposed inverter control also has facility to protect itself from high fault current. Existing maximum power point tracker (MPPT) algorithm is modified to limit the speed of generator during fault. Extensive simulation results using MATLAB/SIMULINK established that the performance of the controllers is quite satisfactory under different fault conditions as well as unbalanced load conditions.

  19. Solar pv fed stand-alone excitation system of a synchronous machine for reactive power generation

    Science.gov (United States)

    Sudhakar, N.; Jain, Siddhartha; Jyotheeswara Reddy, K.

    2017-11-01

    This paper presents a model of a stand-alone solar energy conversion system based on synchronous machine working as a synchronous condenser in overexcited state. The proposed model consists of a Synchronous Condenser, a DC/DC boost converter whose output is fed to the field of the SC. The boost converter is supplied by the modelled solar panel and a day time variable irradiance is fed to the panel during the simulation time. The model also has one alternate source of rechargeable batteries for the time when irradiance falls below a threshold value. Also the excess power produced when there is ample irradiance is divided in two parts and one is fed to the boost converter while other is utilized to recharge the batteries. A simulation is done in MATLAB-SIMULINK and the obtained results show the utility of such modelling for supplying reactive power is feasible.

  20. Use of small stand-alone Internet nodes as a distributed control system

    Science.gov (United States)

    Goodwin, Robert W.; Kucera, Michael J.; Shea, Michael F.

    1994-12-01

    For several years, the standard model for accelerator control systems has been workstation consoles connected to VME local stations by a Local Area Network with analog and digital data being accessed via a field bus to custom I/O interface electronics. Commercially available hardware has now made it possible to implement a small stand-alone data acquisition station that combines the LAN connection, the computer, and the analog and digital I/O interface on a single board. This eliminates the complexity of a field bus and the associated proprietary I/O hardware. A minimum control system is one data acquisition station and a Macintosh or workstation console, both connected to the network; larger systems have more consoles and nodes. An implementation of this architecture is described along with performance and operational experience.

  1. Stand-Alone Photovoltaic System Operation with Energy Management and Fault Tolerant

    International Nuclear Information System (INIS)

    Jmashidpour, Ehsan; Poure, Philippe; Gholipour, E.; Saadate, Shahrokh

    2017-01-01

    This paper presents a stand-alone photovoltaic (PV) system with a fault tolerant operation capability. An energy management method is provided to keep the balance between produced and consumed energy instantaneously. As the storage element, an Ultra-Capacitor (UC) pack is used for facing high frequency variation of the load/source, and batteries are in charge of slow load /source variations. A Maximum Power Point Tracking (MPPT) algorithm is applied to control the boost converter of the PV source to achieve the maximum power. In order to improve the micro-grid service continuity and reliability, a fast fault diagnosis method based on the converter current shape for PV source is applied. Finally, the validity of the proposed energy management and the fault diagnosis method is confirmed by the simulation and experimental results. (author)

  2. Power quality improvement of a stand-alone power system subjected to various disturbances

    Science.gov (United States)

    Lone, Shameem Ahmad; Mufti, Mairaj Ud-Din

    In wind-diesel stand-alone power systems, the disturbances like random nature of wind power, turbulent wind, sudden changes in load demand and the wind park disconnection effect continuously the system voltage and frequency. The satisfactory operation of such a system is not an easy task and the control design has to take in to account all these subtleties. For maintaining the power quality, generally, a short-term energy storage device is used. In this paper, the performance of a wind-diesel system associated with a superconducting magnetic energy storage (SMES) system is studied. The effect of installing SMES at wind park bus/load bus, on the system performance is investigated. To control the exchange of real and reactive powers between the SMES unit and the wind-diesel system, a control strategy based on fuzzy logic is proposed. The dynamic models of the hybrid power system for most common scenarios are developed and the results presented.

  3. JAERI Fuel Cleanup System (J-FCU) stand-alone tritium test at the TSTA

    International Nuclear Information System (INIS)

    Konishi, Satoshi; Hayashi, Takumi; Inoue, Masahiko

    1993-03-01

    JAERI designed, fabricated, and installed the JAERI Fuel Cleanup System (J-FCU) as a subsystem of simulated fusion fuel loop at the TSTA. The main function of the J-FCU is to purify and to recover hydrogen isotopes from simulated plasma exhaust while exhausting tritium free impurities. After a lot of deuterium tests, a first tritium test of the J-FCU was performed with one gram of tritium at the TSTA on June 1991. Main purpose of this test was to evaluate the total integrity and function of the J-FCU system with a DT mixture. Through this test, the J-FCU was operated well and its function with tritium was demonstrated. This report describes the detail test results of the J-FCU first tritium test and discuss its functions by stand-alone mode. Residual tritium inventory of the J-FCU system was also discussed. (author)

  4. System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

    Science.gov (United States)

    Nixon, D. D.

    2001-01-01

    Conventional construction of digital dynamic system simulations often involves collecting differential equations that model each subsystem, arran g them to a standard form, and obtaining their numerical gin solution as a single coupled, total-system simultaneous set. Simulation by numerical coupling of independent stand-alone subsimulations is a fundamentally different approach that is attractive because, among other things, the architecture naturally facilitates high fidelity, broad scope, and discipline independence. Recursive feedback is defined and discussed as a candidate approach to multidiscipline dynamic system simulation by numerical coupling of self-contained, single-discipline subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Distributed and centralized implementations of coupling have been considered. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

  5. Imagery rescripting as a stand-alone treatment for patients with social phobia: a case series.

    Science.gov (United States)

    Frets, Petra G; Kevenaar, Ciska; van der Heiden, Colin

    2014-03-01

    The majority of patients with social phobia reports experiencing negative images, usually linked to memories of earlier aversive social experiences. Several studies have indicated that such negative self-imagery appears to have a causal role in maintaining social phobia, which suggests that interventions aimed at dealing with these images could be beneficial in the treatment of social phobia. One potentially powerful approach is imagery rescripting (IR), a clinical intervention that focuses on changing the meaning and impact of unpleasant memories. In the treatment of social phobia IR was only used as part of a broader cognitive-behavioral treatment package. However, we propose that IR alone might also be an effective treatment for this anxiety disorder. The present study reports an initial evaluation of the application of IR as a stand-alone treatment for six adult outpatients presenting with social phobia. A single case series using an A-B replication across patients design was employed. Following a no-treatment baseline period, IR was delivered weekly and patients were followed up for 3 and 6 months. For all patients, substantial reductions were obtained on all outcome measures at post-treatment, and gains were largely maintained at 6-months follow-up. The generalizability of the effects of IR for social phobia is limited by the small number of patients treated by only one therapist. The results of this preliminary case series suggest that IR as a stand alone treatment is an apparently effective intervention in the treatment of patients with social phobia, and indicate that controlled evaluation of its efficacy might be worthwhile. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Optimal expansion planning of stand-alone systems with stochastic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hoese, Alejandro [Instituto de Energia Electrica (IEE), Universidad Nacional de San Juan, (Argentina)

    1997-12-31

    Stand-alone systems in the range of 1 kW - 10 MW are taking relevance in the new (global) liberal concept of energy market. State and private investors are becoming increasingly attention on the use of renewable for these systems, but it must be shown that these non-conventional solutions are competitive with the established conventional ones. The high investment costs and the technical and economic uncertainties coupled with the use of time-dependent energy sources are the mainly inhibiting factors for the decision agents to choose these systems instead of conventional ones. In the paper a new model for optimal expansion planning of hybrid stand-alone generating systems under consideration of uncertainties is presented. This model is at present in {sup d}evelopment state{sup .} Results already obtained in the first steps of this research are promising and some of them are here presented. [Espanol] Los sistemas autocontenidos en el rango de 1 Kw a 10 MW estan tomando importancia en el nuevo (global) concepto liberal del mercado de la energia. Inversionistas privados y del Estado estan poniendo mayor atencion en el uso de energias renovables para estos sistemas, pero debe mostrarse que estas soluciones no-convencionales son competitivas con las convencionales establecidas. Los altos costos de inversion y las incertidumbres tecnicas y economicas aunadamente con el uso de fuentes de energia dependientes del tiempo son los principales factores inhibidores de los factores de decision para escoger estos sistemas en lugar de los convencionales. En este articulo se presenta un nuevo modelo de planeacion de expansion optima de sistemas hibridos autocontenidos de generacion electrica bajo la consideracion de incertidumbres. Este modelo esta actualmente en {sup e}stado de desarrollo{sup .} Los resultados ya obtenidos en las primeras etapas de esta investigacion son prometedores y se presentan algunos de ellos.

  7. Diagnostic value of the stand-alone synthetic image in digital breast tomosynthesis examinations.

    Science.gov (United States)

    Garayoa, Julia; Chevalier, Margarita; Castillo, Maria; Mahillo-Fernández, Ignacio; Amallal El Ouahabi, Najim; Estrada, Carmen; Tejerina, Alejandro; Benitez, Olivia; Valverde, Julio

    2018-02-01

    To demonstrate the non-inferiority of synthetic image (SI) mammography versus full-field digital mammography (FFDM) in breast tomosynthesis (DBT) examinations. An observational, retrospective, single-centre, multireader blinded study was performed, using 2384 images to directly compare SI and FFDM based on Breast Imaging Reporting and Data System (BIRADS) categorisation and visibility of radiological findings. Readers had no access to digital breast tomosynthesis slices. Multiple reader, multiple case (MRMC) receiver operating characteristic (ROC) methodology was used to compare the diagnostic performance of SI and FFDM images. The kappa statistic was used to estimate the inter-reader and intra-reader reliability. The area under the ROC curves (AUC) reveals the non-inferiority of SI versus FFDM based on BIRADS categorisation [difference between AUC (ΔAUC), -0.014] and lesion visibility (ΔAUC, -0.001) but the differences were not statistically significant (p=0.282 for BIRADS; p=0.961 for lesion visibility). On average, 77.4% of malignant lesions were detected with SI versus 76.5% with FFDM. Sensitivity and specificity of SI are superior to FFDM for malignant lesions scored as BIRADS 5 and breasts categorised as BIRADS 1. SI is not inferior to FFDM when DBT slices are not available during image reading. SI can replace FFDM, reducing the dose by 45%. • Stand-alone SI demonstrated performance not inferior for lesion visibility as compared to FFDM. • Stand-alone SI demonstrated performance not inferior for lesion BIRADS categorisation as compared to FFDM. • Synthetic images provide important dose savings in breast tomosynthesis examinations.

  8. Energy management system for stand-alone diesel-wind-biomass microgrid with energy storage system

    International Nuclear Information System (INIS)

    Wang, Chengshan; Liu, Yixin; Li, Xialin; Guo, Li; Qiao, Lei; Lu, Hai

    2016-01-01

    An energy management system for stand-alone microgrid composed of diesel generators, wind turbine generator, biomass generator and an ESS (energy storage system) is proposed in this paper. Different operation objectives are achieved by a hierarchical control structure with different time scales. Firstly, the optimal schedules of the diesel generators, wind turbine generator, biomass generator and ESS are determined fifteen minutes ahead according to the super short-term forecast of load and wind speed in the optimal scheduling layer. Comprehensive analysis which takes the uncertainty of load and wind speed into account is conducted in this layer to minimize the operation cost of the system and ensure a desirable range of the state of charge of the ESS. Secondly, the operation points of each unit are regulated dynamically to guarantee real-time power balance and safety range of diesel generation in the real-time control layer, based on which the response capability when suffering significant forecast deviation and other emergency issues, e.g. sudden load-up can be improved. Finally, the effectiveness of the proposed energy management strategy is verified on an RT-Lab based real-time simulation platform, and the economic performances with different types of ESS are analyzed as well. - Highlights: • A hierarchical control strategy is proposed for a stand-alone microgrid. • The uncertainties of load and wind speed have been considered. • Better economic performance and high reliability of the system can be achieved. • The influences of different energy storage systems have been analyzed.

  9. A Meta-Analytic Review of Stand-Alone Interventions to Improve Body Image.

    Directory of Open Access Journals (Sweden)

    Jessica M Alleva

    Full Text Available Numerous stand-alone interventions to improve body image have been developed. The present review used meta-analysis to estimate the effectiveness of such interventions, and to identify the specific change techniques that lead to improvement in body image.The inclusion criteria were that (a the intervention was stand-alone (i.e., solely focused on improving body image, (b a control group was used, (c participants were randomly assigned to conditions, and (d at least one pretest and one posttest measure of body image was taken. Effect sizes were meta-analysed and moderator analyses were conducted. A taxonomy of 48 change techniques used in interventions targeted at body image was developed; all interventions were coded using this taxonomy.The literature search identified 62 tests of interventions (N = 3,846. Interventions produced a small-to-medium improvement in body image (d+ = 0.38, a small-to-medium reduction in beauty ideal internalisation (d+ = -0.37, and a large reduction in social comparison tendencies (d+ = -0.72. However, the effect size for body image was inflated by bias both within and across studies, and was reliable but of small magnitude once corrections for bias were applied. Effect sizes for the other outcomes were no longer reliable once corrections for bias were applied. Several features of the sample, intervention, and methodology moderated intervention effects. Twelve change techniques were associated with improvements in body image, and three techniques were contra-indicated.The findings show that interventions engender only small improvements in body image, and underline the need for large-scale, high-quality trials in this area. The review identifies effective techniques that could be deployed in future interventions.

  10. Optimal expansion planning of stand-alone systems with stochastic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hoese, Alejandro [Instituto de Energia Electrica (IEE), Universidad Nacional de San Juan, (Argentina)

    1998-12-31

    Stand-alone systems in the range of 1 kW - 10 MW are taking relevance in the new (global) liberal concept of energy market. State and private investors are becoming increasingly attention on the use of renewable for these systems, but it must be shown that these non-conventional solutions are competitive with the established conventional ones. The high investment costs and the technical and economic uncertainties coupled with the use of time-dependent energy sources are the mainly inhibiting factors for the decision agents to choose these systems instead of conventional ones. In the paper a new model for optimal expansion planning of hybrid stand-alone generating systems under consideration of uncertainties is presented. This model is at present in {sup d}evelopment state{sup .} Results already obtained in the first steps of this research are promising and some of them are here presented. [Espanol] Los sistemas autocontenidos en el rango de 1 Kw a 10 MW estan tomando importancia en el nuevo (global) concepto liberal del mercado de la energia. Inversionistas privados y del Estado estan poniendo mayor atencion en el uso de energias renovables para estos sistemas, pero debe mostrarse que estas soluciones no-convencionales son competitivas con las convencionales establecidas. Los altos costos de inversion y las incertidumbres tecnicas y economicas aunadamente con el uso de fuentes de energia dependientes del tiempo son los principales factores inhibidores de los factores de decision para escoger estos sistemas en lugar de los convencionales. En este articulo se presenta un nuevo modelo de planeacion de expansion optima de sistemas hibridos autocontenidos de generacion electrica bajo la consideracion de incertidumbres. Este modelo esta actualmente en {sup e}stado de desarrollo{sup .} Los resultados ya obtenidos en las primeras etapas de esta investigacion son prometedores y se presentan algunos de ellos.

  11. Key factors for the implementation of successful, stand-alone village electrification schemes in Peru

    Science.gov (United States)

    Sanchez-Campos, Teodoro

    The hypothesis of this work is that there are social, financial, technical, managerial institutional and political key factors that may either support or prevent the success of small stand alone energy systems in rural areas. This research work aims at contributing to the identification of such factors and study their relevance to the performance and sustainability of stand alone energy systems in rural areas; to meet its purpose, a wide range of literature was reviewed including rural electrification programmes and projects, research and development projects on access to electricity in rural areas, impact studies and others, and a field research survey was done the Andes and Upper Jungle regions in Peru. Nineteen possible critical factors were identified, thirteen with relevance at the local context (the community or village), and six with relevance at the national (or wider) context. From literature review it was found that the possible local critical factors were relevant only to four categories of factors instead of the six considered initially (i.e. social, financial, technological and managerial): the other two categories, political and institutional were found to be more relevant to the national context, therefore those were included in the group of possible critical factors of wider context. A series of questionnaires were designed to collect field data information, which was later used to analyse and establish the relation of each identified factor with the success of the systems studied. The survey research was implemented in 14 villages, 7 with small diesel sets and 7 with small hydropower schemes, all spread in the Andes and Upper Jungle of Peru, which were carefully selected to be representative of regions with isolated stand alone systems and with different socioeconomic background. Out of the 13 possible critical factors of local context, it was found that only 3 are really critical, the others are important but not critical; one of them (technical

  12. Multi-objective analytical model for optimal sizing of stand-alone photovoltaic water pumping systems

    International Nuclear Information System (INIS)

    Olcan, Ceyda

    2015-01-01

    Highlights: • An analytical optimal sizing model is proposed for PV water pumping systems. • The objectives are chosen as deficiency of power supply and life-cycle costs. • The crop water requirements are estimated for a citrus tree yard in Antalya. • The optimal tilt angles are calculated for fixed, seasonal and monthly changes. • The sizing results showed the validity of the proposed analytical model. - Abstract: Stand-alone photovoltaic (PV) water pumping systems effectively use solar energy for irrigation purposes in remote areas. However the random variability and unpredictability of solar energy makes difficult the penetration of PV implementations and complicate the system design. An optimal sizing of these systems proves to be essential. This paper recommends a techno-economic optimization model to determine optimally the capacity of the components of PV water pumping system using a water storage tank. The proposed model is developed regarding the reliability and cost indicators, which are the deficiency of power supply probability and life-cycle costs, respectively. The novelty is that the proposed optimization model is analytically defined for two-objectives and it is able to find a compromise solution. The sizing of a stand-alone PV water pumping system comprises a detailed analysis of crop water requirements and optimal tilt angles. Besides the necessity of long solar radiation and temperature time series, the accurate forecasts of water supply needs have to be determined. The calculation of the optimal tilt angle for yearly, seasonally and monthly frequencies results in higher system efficiency. It is, therefore, suggested to change regularly the tilt angle in order to maximize solar energy output. The proposed optimal sizing model incorporates all these improvements and can accomplish a comprehensive optimization of PV water pumping systems. A case study is conducted considering the irrigation of citrus trees yard located in Antalya, Turkey

  13. Five-year durability of stand-alone interspinous process decompression for lumbar spinal stenosis

    Directory of Open Access Journals (Sweden)

    Nunley PD

    2017-09-01

    Full Text Available Pierce D Nunley,1 Vikas V Patel,2 Douglas G Orndorff,3 William F Lavelle,4 Jon E Block,5 Fred H Geisler6 1Spine Institute of Louisiana, Shreveport, LA, 2The Spine Center, University of Colorado Hospital, Denver, CO, 3Spine Colorado, Mercy Regional Hospital, Durango, CO, 4Upstate Bone and Joint Center, East Syracuse, NY, 5Independent Consultant, San Francisco, CA, 6Independent Consultant, Chicago, IL, USA Background: Lumbar spinal stenosis is the most common indication for spine surgery in older adults. Interspinous process decompression (IPD using a stand-alone spacer that functions as an extension blocker offers a minimally invasive treatment option for intermittent neurogenic claudication associated with spinal stenosis.Methods: This study evaluated the 5-year clinical outcomes for IPD (Superion® from a randomized controlled US Food and Drug Administration (FDA noninferiority trial. Outcomes included Zurich Claudication Questionnaire (ZCQ symptom severity (ss, physical function (pf, and patient satisfaction (ps subdomains, leg and back pain visual analog scale (VAS, and Oswestry Disability Index (ODI.Results: At 5 years, 84% of patients (74 of 88 demonstrated clinical success on at least two of three ZCQ domains. Individual ZCQ domain success rates were 75% (66 of 88, 81% (71 of 88, and 90% (79 of 88 for ZCQss, ZCQpf, and ZCQps, respectively. Leg and back pain success rates were 80% (68 of 85 and 65% (55 of 85, respectively, and the success rate for ODI was 65% (57 of 88. Percentage improvements over baseline were 42%, 39%, 75%, 66%, and 58% for ZCQss, ZCQpf, leg and back pain VAS, and ODI, respectively (all P<0.001. Within-group effect sizes were classified as very large for four of five clinical outcomes (ie, >1.0; all P<0.0001. Seventy-five percent of IPD patients were free from reoperation, revision, or supplemental fixation at their index level at 5 years.Conclusion: After 5 years of follow-up, IPD with a stand-alone spacer provides

  14. Efficiency of hydrogen gas production in a stand-alone solar hydrogen system

    International Nuclear Information System (INIS)

    Singh, K.; Tamakloe, R.Y.

    2003-01-01

    Many photovoltaic systems operate in a decentralised electricity producing system, or stand-alone mode and the total energy demand is met by the output of the photovoltaic array. The output of the photovoltaic system fluctuates and is unpredictable for many applications making some forms of energy storage system necessary. The role of storage medium is to store the excess energy produced by the photovoltaic arry, to absorb momentary power peaks and to supply energy during sunless periods. One of the storage modes is the use of electrochemical techniques, with batteries and water electrolysis as the most important examples. The present study includes three main parts: the first one is the hydrogen production form the electrolysis of water depending on the DC output current of the photovoltaic (PV) energy source and the charging of the battery. The second part presents the influence of various parameters on the efficiency of hydrogen gas production. The final part includes simulation studies with focus on solar hydrogen efficiency under the influence of various physical and chemical parameters. For a 50W panel-battery-electrolyser system, the dependence of volume of hydrogen gas on voltage, current and power yielded a maximum efficiency of 13.6% (author)

  15. Control of a Stand-Alone Variable Speed Wind Energy Supply System †

    Directory of Open Access Journals (Sweden)

    Mohamed M. Hamada

    2013-04-01

    Full Text Available This paper presents a simple control strategy for the operation of a variable speed stand-alone wind turbine with a permanent magnet synchronous generator (PMSG. The PMSG is connected to a three phase resistive load through a switch mode rectifier and a voltage source inverter. Control of the generator side converter is used to achieve maximum power extraction from the available wind power. Control of the DC-DC bidirectional buck-boost converter, which is connected between batteries bank and DC-link voltage, is used to maintain the DC-link voltage at a constant value. It is also used to make the batteries bank stores the surplus of wind energy and supplies this energy to the load during a wind power shortage. The load side voltage source inverter uses a relatively complex vector control scheme to control the output load voltage in terms of amplitude and frequency. The control strategy works under wind speed variation as well as with variable load. Extensive simulation results have been performed using MATLAB/SIMULINK.

  16. Optimal sizing method for constituent elements of stand-alone photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Hirotada; Oi, Yoichi [Hokuriku Electric Power Co., Inc. Toyama (Japan)

    1988-12-25

    The purpose of the report was to calculate the optimal volume of constituent elements of stand-alone photovoltaic power systems, based on the distribution of global radiation on an inclined surface (herein-after called flux of solar radiation), which had been previously measured, and the size of load to be supplied. The least power generation cost was calculated, supposing that setting load was 176kWh/month and the loss of load probability (LOLP) was 1%, by using actual amount of solar radiation in May 1985. The cost was divided into two components: one was proportionate to the size of solar cell, and the other was in proportion to the battery volume. And then, the cost of twenty-year operation(TLC) was calculated. The size of array and the battery volume, which minimize the cost, can be determined when TLC is differentiate. Since auxiliary power source is not attached to this system, it is necessary to restrict the load in order to meet the electric power shortage. In case of the cost at construction in 1984, a standard model indicating the least power generation cost is a photovoltaic system with the array size of A=49.0m{sup 2} and the battery volume of Q=568(Ah). 4 refs., 9 figs., 10 tabs.

  17. Battery Storage Technologies for Electrical Applications: Impact in Stand-Alone Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Daniel Akinyele

    2017-11-01

    Full Text Available Batteries are promising storage technologies for stationary applications because of their maturity, and the ease with which they are designed and installed compared to other technologies. However, they pose threats to the environment and human health. Several studies have discussed the various battery technologies and applications, but evaluating the environmental impact of batteries in electrical systems remains a gap that requires concerted research efforts. This study first presents an overview of batteries and compares their technical properties such as the cycle life, power and energy densities, efficiencies and the costs. It proposes an optimal battery technology sizing and selection strategy, and then assesses the environmental impact of batteries in a typical renewable energy application by using a stand-alone photovoltaic (PV system as a case study. The greenhouse gas (GHG impact of the batteries is evaluated based on the life cycle emission rate parameter. Results reveal that the battery has a significant impact in the energy system, with a GHG impact of about 36–68% in a 1.5 kW PV system for different locations. The paper discusses new batteries, strategies to minimize battery impact and provides insights into the selection of batteries with improved cycling capacity, higher lifespan and lower cost that can achieve lower environmental impacts for future applications.

  18. [Clinical application of stand-alone MC+PEEK cage in the anterior cervical fusion].

    Science.gov (United States)

    Jiang, Bing; Cao, Yan-Qing; Pan, Hong; Zhu, Cheng-Run; Zhang, Xiao-Jun; Tao, Yue-Feng; Liu, Zhen

    2015-04-01

    To explore the effect of clinical application of stand-alone MC+PEEK cage in anterior cervical fusion. From January 2011 to January 2014,50 patients were treated with the MC+PEEK cage filled with autogenous cancellous illic-bone graft after anterior cervical discectomy. There were 22 patients with cervical spondylosis,26 patients with traumatic cervical disc herniation, 2 patients with cervical instability in these patients. There were 32 males and 18 females, aged from 30 to 79 years old with an average of 53.30 years old. There were 32 patients with single segment, 15 patients with double segments and 3 patients with three segments. Cervical AP and lateral and the flexion-extension X-rays were regularly taken in order to assess the cervical physiological curvature, the graft fusion and internal fixation related complications. Nerve function, clinical effect and bone fusion were respectively evaluated according to Japan Orthopedic Association (JOA), Otani grade and Suk method. All patients were followed up from 6 to 36 months with an average of 20 months. No correlated surgical complications were found and all patients obtained bony fusion with an average time of 4.30 months. JOA score had significantly improvement after surgery (P cervical fusion can obtain satisfactory clinical effect with less operation injury and reduce the complications. It is a better fusion method in anterior cervical fusion.

  19. Performance and Simulation of a Stand-alone Parabolic Trough Solar Thermal Power Plant

    Science.gov (United States)

    Mohammad, S. T.; Al-Kayiem, H. H.; Assadi, M. K.; Gilani, S. I. U. H.; Khlief, A. K.

    2018-05-01

    In this paper, a Simulink® Thermolib Model has been established for simulation performance evaluation of Stand-alone Parabolic Trough Solar Thermal Power Plant in Universiti Teknologi PETRONAS, Malaysia. This paper proposes a design of 1.2 kW parabolic trough power plant. The model is capable to predict temperatures at any system outlet in the plant, as well as the power output produced. The conditions that are taken into account as input to the model are: local solar radiation and ambient temperatures, which have been measured during the year. Other parameters that have been input to the model are the collector’s sizes, location in terms of latitude and altitude. Lastly, the results are presented in graphical manner to describe the analysed variations of various outputs of the solar fields obtained, and help to predict the performance of the plant. The developed model allows an initial evaluation of the viability and technical feasibility of any similar solar thermal power plant.

  20. Comparative analysis of distributed MPPT controllers for partially shaded stand alone photovoltaic systems

    International Nuclear Information System (INIS)

    Muthuramalingam, M.; Manoharan, P.S.

    2014-01-01

    Highlights: • Analyzes the performance of ANN and ANFIS MPPT algorithms by stand alone PV system. • ISSBC with ANFIS can provide the overall efficiency higher than ANN. • CHBMLI integrate with SHE ANN modulation technique improve output voltage quality. • Simulation and hardware results show the ANFIS algorithm efficient than ANN algorithm. - Abstract: This paper presents a unique combination of an interleaved soft switched boost converter (ISSBC) run by a set of two photovoltaic panel (PV) with a distributed MPPT, suitable to guarantee MPPT even under partial shadowed conditions, managed by an adaptive neuro fuzzy inference system trained by the training data derived from a particle swarm optimization (PSO–ANFIS) unit. The ISSBC is followed by a, single phase cascaded H bridge five-level inverter (CHI) driven by the individual DC outputs of the ISSBC, with selective harmonic elimination scheme to eliminate typically the seventh order harmonics. A comparison of different intelligent distributed maximum power point tracking (MPPT) algorithms for photovoltaic (PV) system under partial shadow conditions is carried out. The use of the ISSBC guarantees mitigation of ripple and it is meant to handle higher currents with minimal switching losses. Simulation was carried out in the Matlab Simulink environment and an experimental verification with a scaled down model validated the proposed scheme. It has been thus established, by both simulation and experimental verification, that the PSO–ANFIS model of distributed MPPT scheme of control outperforms other schemes of control for MPPT

  1. Can aqueous hydrogen peroxide be used as a stand-alone energy source?

    International Nuclear Information System (INIS)

    Disselkamp, Robert S.

    2010-01-01

    A novel electrochemical scheme to convert a stand-alone supply of aqueous hydrogen peroxide into a fuel cell-ready stream of hydrogen gas plus aqueous hydrogen peroxide is described. The electrochemical cell, consisting of a solid base and solid acid electrocatalyst, together with a proton exchange membrane, comprise the system that converts aqueous hydrogen peroxide into separate gas streams of oxygen and hydrogen. Aqueous hydrogen peroxide is contained in the anode compartment only and exists in the region where oxygen gas is formed, whereas the cathode compartment is where hydrogen gas is generated and therefore exists in a reduced state. A near zero theoretical over-potential can be achieved by the choice of basicity and acidity of the electrode materials. The primary cost of the electrochemical cell is electrode construction and the aqueous hydrogen peroxide energy storage compound. Additional research effort is required to experimentally validate the concept and explore the full economic impact should initial studies, based on the design presented here, prove promising. (author)

  2. An intelligent stand-alone ultrasonic device for monitoring local structural damage: implementation and preliminary experiments

    International Nuclear Information System (INIS)

    Pertsch, Alexander; Kim, Jin-Yeon; Wang, Yang; Jacobs, Laurence J

    2011-01-01

    Continuous structural health monitoring has the potential to significantly improve the safety management of aged, in-service civil structures. In particular, monitoring of local damage growth at hot-spot areas can help to prevent disastrous structural failures. Although ultrasonic nondestructive evaluation (NDE) has proved to be effective in monitoring local damage growth, conventional equipment and devices are usually bulky and only suitable for scheduled human inspections. The objective of this research is to harness the latest developments in embedded hardware and wireless communication for developing a stand-alone, compact ultrasonic device. The device is directed at the continuous structural health monitoring of civil structures. Relying on battery power, the device possesses the functionalities of high-speed actuation, sensing, signal processing, and wireless communication. Integrated with contact ultrasonic transducers, the device can generate 1 MHz Rayleigh surface waves in a steel specimen and measure response waves. An envelope detection algorithm based on the Hilbert transform is presented for efficiently determining the peak values of the response signals, from which small surface cracks are successfully identified

  3. Approaches for developing a sizing method for stand-alone PV systems with variable demand

    Energy Technology Data Exchange (ETDEWEB)

    Posadillo, R. [Grupo de Investigacion en Energias y Recursos Renovables, Dpto. de Fisica Aplicada, E.P.S., Universidad de Cordoba, Avda. Menendez Pidal s/n, 14004 Cordoba (Spain); Lopez Luque, R. [Grupo de Investigacion de Fisica para las Energias y Recursos Renovables, Dpto. de Fisica Aplicada. Edificio C2 Campus de Rabanales, 14071 Cordoba (Spain)

    2008-05-15

    Accurate sizing is one of the most important aspects to take into consideration when designing a stand-alone photovoltaic system (SAPV). Various methods, which differ in terms of their simplicity or reliability, have been developed for this purpose. Analytical methods, which seek functional relationships between variables of interest to the sizing problem, are one of these approaches. A series of rational considerations are presented in this paper with the aim of shedding light upon the basic principles and results of various sizing methods proposed by different authors. These considerations set the basis for a new analytical method that has been designed for systems with variable monthly energy demands. Following previous approaches, the method proposed is based on the concept of loss of load probability (LLP) - a parameter that is used to characterize system design. The method includes information on the standard deviation of loss of load probability ({sigma}{sub LLP}) and on two new parameters: annual number of system failures (f) and standard deviation of annual number of failures ({sigma}{sub f}). The method proves useful for sizing a PV system in a reliable manner and serves to explain the discrepancies found in the research on systems with LLP<10{sup -2}. We demonstrate that reliability depends not only on the sizing variables and on the distribution function of solar radiation, but on the minimum value as well, which in a given location and with a monthly average clearness index, achieves total solar radiation on the receiver surface. (author)

  4. Stand-alone excitation synchronous wind power generators with power flow management strategy

    Directory of Open Access Journals (Sweden)

    Tzuen-Lih Chern

    2014-09-01

    Full Text Available This study presents a stand-alone excitation synchronous wind power generator (SESWPG with power flow management strategy (PFMS. The rotor speed of the excitation synchronous generator tracks the utility grid frequency by using servo motor tracking technologies. The automatic voltage regulator governs the exciting current of generator to achieve the control goals of stable voltage. When wind power is less than the needs of the consumptive loading, the proposed PFMS increases motor torque to provide a positive power output for the loads, while keeping the generator speed constant. Conversely, during the periods of wind power greater than output loads, the redundant power of generator production is charged to the battery pack and the motor speed remains constant with very low power consumption. The advantage of the proposed SESWPG is that the generator can directly output stable alternating current (AC electricity without using additional DC–AC converters. The operation principles with software simulation for the system are described in detail. Experimental results of a laboratory prototype are shown to verify the feasibility of the system.

  5. Analysis and control of induction generator supplying stand-alone AC loads employing a Matrix Converter

    Directory of Open Access Journals (Sweden)

    Sumedha Mahajan

    2017-04-01

    Full Text Available This paper proposes a Capacitor Excited Induction Generator (CEIG-Matrix Converter (MC system for feeding stand-alone AC loads. The variable output voltage magnitude and frequency from CEIG is converted into a constant voltage magnitude and frequency at the load terminals by controlling MC using Space Vector Modulation (SVM technique. This single-stage MC is turned up as a good alternative for the proposed system against commonly used AC/DC/AC two stage power converters. The configuration and implementation of the closed-loop control scheme employing dSPACE 1103 real time controller have been fully described in the paper. The proposed closed-loop controller regulates the AC load voltage irrespective of changes in the prime mover speed and load. A method for predetermining the steady-state performance of the proposed system has been developed and described with relevant analytical expressions. The effectiveness of the proposed system is exemplified through simulation results for various operating conditions. The proposed control technique is further validated using an experimental setup developed in the laboratory.

  6. Design of a reliable and low-cost stand-alone micro hydropower station

    Energy Technology Data Exchange (ETDEWEB)

    Kusakana, K.; Munda, J.L. [Tshwane Univ. of Technology, Pretoria (South Africa)

    2008-07-01

    A stand-alone micro-hydropower station was presented. The plant was comprised of a squirrel cage induction machine coupled to a Kaplan water turbine. Power converters were used to control the variable frequency and voltage outputs of the generator caused by variations in water flow. The hydropower plant was installed a farm in the Kwazulu-Natal region of South Africa, and was designed to provide electricity in relation to the low power demand of users in the region as well as according to the site's hydrology and topology. Load forecasts for the 8 houses using the system were conducted. A generator with a higher output than the average power needed to feed the load was selected in order to ensure load supply during peak demand. The system was designed to shore energy generated during off-peak periods in batteries. An AC-DC-AC converter was used as an interface between the generator and the load in order to ensure voltage and frequency stabilization. Simulations of plant components were conducted to demonstrate output power supply during water flow variations. Results of the modelling study indicated that power converters are needed to stabilize generator outputs. The hydropower design is a cost-effective means of supplying power to low-income households. 10 refs., 2 tabs., 7 figs.

  7. Simulation of stand alone PV system; Dokuritsugata taiyoko hatsuden system no simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, H; Ogawa, H; Sekii, Y [Chiba Institute of Technology, Chiba (Japan); Tsuda, I; Nozaki, K [Electrotechnical Laboratory, Tsukuba (Japan); Kurokawa, K [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1996-10-27

    In order to evaluate the simulation results of a photovoltaic power generation system, an operation simulation was carried out using the actual measured data of a stand alone PV system in Miyakojima, Okinawa Prefecture, so as to make a comparison with the actual operation data. The electric power was supplied to 250 houses and primary/junior high schools in the surrounding villages, which had an average demand load of approximately 90kw and the maximum of approximately 200kw. The power was supplied through the PV power generation in the duration of the sunshine, with an excess power charged in storage batteries and then supplied from the batteries at night. The array capacity was made 750kWp, the output current and storage batteries being characteristic type with an actual efficiency curve used for the inverter. The weather data used were the actual inclined insolation quantity and the outside air temperature data for a period of one month of November. The power charged in excess of 100% in the batteries was termed as an overflow power. With the charging condition 30% or less, a diesel generator was run for a rated operation for one hour, the power of which was termed as a backup power. As a result, the simulation was found nearly in agreement with the actual measurements. 5 refs., 7 figs., 2 tabs.

  8. Solar photovoltaic applications seminar: design, installation and operation of small, stand-alone photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    This seminar material was developed primarily to provide solar photovoltaic (PV) applied engineering technology to the Federal community. An introduction to photoconductivity, semiconductors, and solar photovoltaic cells is included along with a demonstration of specific applications and application identification. The seminar details general systems design and incorporates most known information from industry, academia, and Government concerning small solar cell power system design engineering, presented in a practical and applied manner. Solar PV power system applications involve classical direct electrical energy conversion and electric power system analysis and synthesis. Presentations and examples involve a variety of disciplines including structural analysis, electric power and load analysis, reliability, sizing and optimization; and, installation, operation and maintenance. Four specific system designs are demonstrated: water pumping, domestic uses, navigational and aircraft aids, and telecommunications. All of the applications discussed are for small power requirement (under 2 kilowatts), stand-alone systems to be used in remote locations. Also presented are practical lessons gained from currently installed and operating systems, problems at sites and their resolution, a logical progression through each major phase of system acquisition, as well as thorough design reviews for each application.

  9. Use of Super-Capacitor to Enhance Charging Performance of Stand-Alone Solar PV System

    KAUST Repository

    Huang, B. J.

    2011-01-01

    Introduction: The battery charging performance in a stand-alone solar PV system affects the PV system efficiency and the load operating time. The New Energy Center of National Taiwan University has been devoted to the development of a PWM charging technique to continue charging the lead-acid battery after the overcharge point to increase the battery storage capacity by more than 10%. The present study intends to use the super-capacitor to further increase the charge capacity before the overcharge point of the battery. The super-capacitor is connected in parallel to the lead-acid battery. This will reduce the overall charging impedance during the charge and increase the charging current, especially in sunny weather. A system dynamics model of the lead-acid battery and super-capacitor was derived and the control system simulation was carried out to predict the charging performance for various weathers. It shows that the overall battery impedance decreases and charging power increases with increasing solar radiation. An outdoor comparative test for two identical PV systems with and without supercapacitor was carried out. The use of super-capacitor is shown to be able to increase the lead-acid charging capacity by more than 25% at sunny weather and 10% in cloudy weather. © Springer-Verlag Berlin Heidelberg 2011.

  10. On the economics of stand-alone renewable hybrid power plants in remote regions

    International Nuclear Information System (INIS)

    Petrakopoulou, Fontina

    2016-01-01

    Highlights: • Economic evaluation of three renewable hybrid power plants for off-grid operation. • The high electricity cost of remote regions increases the competitiveness of renewable energy. • The proposed plants are economically viable when compared to the existing situation. • The zero direct emissions of the plants constitute an additional advantage of the plants. - Abstract: In recent years ever more examples of regions that have managed to achieve or orientate themselves toward renewable energy sufficiency are emerging. However, actions to create energy autonomy are mainly the result of isolated activities and they are less driven from fully organized movements. In addition, total energy independence without the support of a centralized electrical grid is yet to be achieved. The objectives of this work are to investigate the associated costs of stand-alone renewable hybrid power plants on a Greek island and compare them to the cost of the currently used fossil-fuel-based conventional plant. The plants examined here are designed to fully cover the electricity needs of the island. Islands may face numerous energy problems and rely heavily on foreign and environmentally-harmful fuels. It is shown that the relatively high cost of electricity of such a remote region can increase the competitiveness and promote the wider incorporation of technologies based on renewable energy sources that may, in other cases, seem economically inferior to business-as-usual energy solutions.

  11. MIRNA-DISTILLER: a stand-alone application to compile microRNA data from databases

    Directory of Open Access Journals (Sweden)

    Jessica K. Rieger

    2011-07-01

    Full Text Available MicroRNAs (miRNA are small non-coding RNA molecules of ~22 nucleotides which regulate large numbers of genes by binding to seed sequences at the 3’-UTR of target gene transcripts. The target mRNA is then usually degraded or translation is inhibited, although thus resulting in posttranscriptional down regulation of gene expression at the mRNA and/or protein level. Due to the bioinformatic difficulties in predicting functional miRNA binding sites, several publically available databases have been developed that predict miRNA binding sites based on different algorithms. The parallel use of different databases is currently indispensable, but highly uncomfortable and time consuming, especially when working with numerous genes of interest. We have therefore developed a new stand-alone program, termed MIRNA-DISTILLER, which allows to compile miRNA data for given target genes from public databases. Currently implemented are TargetScan, microCosm, and miRDB, which may be queried independently, pairwise, or together to calculate the respective intersections. Data are stored locally for application of further analysis tools including freely definable biological parameter filters, customized output-lists for both miRNAs and target genes, and various graphical facilities. The software, a data example file and a tutorial are freely available at http://www.ikp-stuttgart.de/content/language1/html/10415.asp

  12. MIRNA-DISTILLER: A Stand-Alone Application to Compile microRNA Data from Databases.

    Science.gov (United States)

    Rieger, Jessica K; Bodan, Denis A; Zanger, Ulrich M

    2011-01-01

    MicroRNAs (miRNA) are small non-coding RNA molecules of ∼22 nucleotides which regulate large numbers of genes by binding to seed sequences at the 3'-untranslated region of target gene transcripts. The target mRNA is then usually degraded or translation is inhibited, although thus resulting in posttranscriptional down regulation of gene expression at the mRNA and/or protein level. Due to the bioinformatic difficulties in predicting functional miRNA binding sites, several publically available databases have been developed that predict miRNA binding sites based on different algorithms. The parallel use of different databases is currently indispensable, but highly uncomfortable and time consuming, especially when working with numerous genes of interest. We have therefore developed a new stand-alone program, termed MIRNA-DISTILLER, which allows to compile miRNA data for given target genes from public databases. Currently implemented are TargetScan, microCosm, and miRDB, which may be queried independently, pairwise, or together to calculate the respective intersections. Data are stored locally for application of further analysis tools including freely definable biological parameter filters, customized output-lists for both miRNAs and target genes, and various graphical facilities. The software, a data example file and a tutorial are freely available at http://www.ikp-stuttgart.de/content/language1/html/10415.asp.

  13. 49 CFR 1109.4 - Mandatory mediation in rate cases to be considered under the stand-alone cost methodology.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Mandatory mediation in rate cases to be considered... § 1109.4 Mandatory mediation in rate cases to be considered under the stand-alone cost methodology. (a) A... methodology must engage in non-binding mediation of its dispute with the railroad upon filing a formal...

  14. An improved synchronous reference frame phase-locked loop for stand-alone variable speed constant frequency power generation systems

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Ke, Longzhang

    2017-01-01

    The phase-locked loop (PLL) based on conventional synchronous reference frame, i.e. dqPLL, is usually employed in grid-connected variable speed constant frequency (VSCF) power generation systems (PGSs). However, the voltage amplitude drop of stand-alone PGSs is often greater than that of the grid...

  15. Analyzing grid extension and stand-alone photovoltaic systems for the cost-effective electrification of Kenya

    NARCIS (Netherlands)

    Zeyringer, Marianne; Pachauri, Shonali; Schmid, Erwin; Schmidt, Johannes; Worrell, Ernst|info:eu-repo/dai/nl/106856715; Morawetz, Ulrich B.

    2015-01-01

    The declaration of 2014-2024 as the Decade of Sustainable Energy for All has catalyzed actions towards achieving universal electricity access. The high costs of building electric infrastructure are a major impediment to improved access, making stand-alone photovoltaic (PV) systems an attractive

  16. Stand-Alone Ethics, Social Responsibility, and Sustainability Course Requirements: A Snapshot from Australia and New Zealand

    Science.gov (United States)

    Rundle-Thiele, Sharyn R.; Wymer, Walter

    2010-01-01

    This article analyzes the extent to which Australian and New Zealand marketing educators use dedicated or stand-alone courses to equip students with alternative views of business. A census of marketing programs in degree-granting universities was conducted. Program brochures were obtained via the Internet and were content analyzed. This study…

  17. Stand-Alone Photovoltaic System Assessment in Warmer Urban Areas in Mexico

    Directory of Open Access Journals (Sweden)

    Alberto-Jesus Perea-Moreno

    2018-01-01

    Full Text Available The aim of this study is to examine the possibility of using a stand-alone photovoltaic system (SAPVS for electricity generation in urban areas in Southern Mexico. In Mexico, an urban area is defined as an area where more than 2500 inhabitants live. Due to constant migration from the countryside to the cities, the number of inhabitants of urban localities has been increasing. Global horizontal irradiation (GHI data were recorded every 10 min during 2014–2016 in Coatzacoalcos in the state of Veracruz located on 18°08′09″ N and 94°27′48″ W. In this study, batteries represented 77% of the total cost, 12 PV panels of 310 W could export 5.41 MWh to the grid, and an inverter with an integrated controller and charger was selected, which decreased the initial cost. The city of Coatzacoalcos was chosen because the average annual temperature is 28°, with an average relative humidity of 75% and an average irradiance of 5.3 kWh/m2/day. An emission factor 0.505 tCO2/MWh of greenhouse gases (GHG were obtained, based on the power system, the reduction of net annual GHG would be 11 tCO2 and a financial revenue of 36.951 × 103 $/tCO2 would be obtained. Financial parameters such as a 36.3% Internal Rate Return (IRR and 3.4 years payback show the financial viability of this investment. SAPVSs in urban areas in Mexico could be a benefit as long as housing has a high consumption of electricity.

  18. The Use of Artificial Neural Networks for Forecasting the Electric Demand of Stand-Alone Consumers

    Science.gov (United States)

    Ivanin, O. A.; Direktor, L. B.

    2018-05-01

    The problem of short-term forecasting of electric power demand of stand-alone consumers (small inhabited localities) situated outside centralized power supply areas is considered. The basic approaches to modeling the electric power demand depending on the forecasting time frame and the problems set, as well as the specific features of such modeling, are described. The advantages and disadvantages of the methods used for the short-term forecast of the electric demand are indicated, and difficulties involved in the solution of the problem are outlined. The basic principles of arranging artificial neural networks are set forth; it is also shown that the proposed method is preferable when the input information necessary for prediction is lacking or incomplete. The selection of the parameters that should be included into the list of the input data for modeling the electric power demand of residential areas using artificial neural networks is validated. The structure of a neural network is proposed for solving the problem of modeling the electric power demand of residential areas. The specific features of generation of the training dataset are outlined. The results of test modeling of daily electric demand curves for some settlements of Kamchatka and Yakutia based on known actual electric demand curves are provided. The reliability of the test modeling has been validated. A high value of the deviation of the modeled curve from the reference curve obtained in one of the four reference calculations is explained. The input data and the predicted power demand curves for the rural settlement of Kuokuiskii Nasleg are provided. The power demand curves were modeled for four characteristic days of the year, and they can be used in the future for designing a power supply system for the settlement. To enhance the accuracy of the method, a series of measures based on specific features of a neural network's functioning are proposed.

  19. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-12-01

    Full Text Available The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal efficiency of the system was found to be 8% with an operating temperature of 120 °C. The hot water produced by the unit has a temperature of 40 °C. Economic assessment was done for 1-kW and 5-kW solar ORC water pumping systems. These systems use different types of solar collectors: a parabolic trough collector (PTC and an evacuated tube collector (ETC. The economic analysis showed that the costs of water are $2.47/m3 (highest and $1.86/m3 (lowest for the 1-kW system and a 150-m pumping head. In addition, the cost of water is reduced when the size of the system is increased and the pumping head is reduced. The minimum volumes of water pumped are 2190 m3 and 11,100 m3 yearly for 1 kW and 5 kW, respectively. The payback period is eight years with a profitability index of 1.6. The system is highly feasible and promising in the context of Nepal.

  20. Optimum capacity determination of stand-alone hybrid generation system considering cost and reliability

    International Nuclear Information System (INIS)

    Chen, Hung-Cheng

    2013-01-01

    Highlights: ► This paper presents a methodology for the installation capacity optimization. ► Hybrid generation system is optimized by application of adaptive genetic algorithm. ► A cost investigation is made under various conditions and component characteristics. ► The optimization scheme is validated to meet the annual power load demand. -- Abstract: The aim of this work is to present an optimization methodology for the installation capacity of a stand-alone hybrid generation system, taking into consideration the cost and reliability. Firstly, on the basis of derived steady state models of a wind generator (WG), a photovoltaic array (PV), a battery and an inverter, the hybrid generation system is modeled for the purpose of capacity optimization. Secondly, the power system is analyzed for determining both the system structure and the operation control strategy. Thirdly, according to hourly weather database of wind speed, temperature and solar irradiation, annual power generation capacity is estimated for the system match design in order that an annual power load demand can be met. The capacity determination of a hybrid generation system becomes complicated as a result of the uncertainty in the renewable energy together with load demand and the nonlinearity of system components. Aimed at the power system reliability and the cost minimization, the capacity of a hybrid generation system is optimized by application of an adaptive genetic algorithm (AGA) to individual power generation units. A total cost investigation is made under various conditions, such as wind generator power curves, battery discharge depth and the loss of load probability (LOLP). At the end of this work, the capacity of a hybrid generation system is optimized at two installation sites, namely the offshore Orchid Island and Wuchi in Taiwan. The optimization scheme is validated to optimize power capacities of a photovoltaic array, a battery and a wind turbine generator with a relative

  1. The eBioKit, a stand-alone educational platform for bioinformatics.

    Science.gov (United States)

    Hernández-de-Diego, Rafael; de Villiers, Etienne P; Klingström, Tomas; Gourlé, Hadrien; Conesa, Ana; Bongcam-Rudloff, Erik

    2017-09-01

    Bioinformatics skills have become essential for many research areas; however, the availability of qualified researchers is usually lower than the demand and training to increase the number of able bioinformaticians is an important task for the bioinformatics community. When conducting training or hands-on tutorials, the lack of control over the analysis tools and repositories often results in undesirable situations during training, as unavailable online tools or version conflicts may delay, complicate, or even prevent the successful completion of a training event. The eBioKit is a stand-alone educational platform that hosts numerous tools and databases for bioinformatics research and allows training to take place in a controlled environment. A key advantage of the eBioKit over other existing teaching solutions is that all the required software and databases are locally installed on the system, significantly reducing the dependence on the internet. Furthermore, the architecture of the eBioKit has demonstrated itself to be an excellent balance between portability and performance, not only making the eBioKit an exceptional educational tool but also providing small research groups with a platform to incorporate bioinformatics analysis in their research. As a result, the eBioKit has formed an integral part of training and research performed by a wide variety of universities and organizations such as the Pan African Bioinformatics Network (H3ABioNet) as part of the initiative Human Heredity and Health in Africa (H3Africa), the Southern Africa Network for Biosciences (SAnBio) initiative, the Biosciences eastern and central Africa (BecA) hub, and the International Glossina Genome Initiative.

  2. "Candidatus Fokinia solitaria", a Novel "Stand-Alone" Symbiotic Lineage of Midichloriaceae (Rickettsiales.

    Directory of Open Access Journals (Sweden)

    Franziska Szokoli

    Full Text Available Recently, the family Midichloriaceae has been described within the bacterial order Rickettsiales. It includes a variety of bacterial endosymbionts detected in different metazoan host species belonging to Placozoa, Cnidaria, Arthropoda and Vertebrata. Representatives of Midichloriaceae are also considered possible etiological agents of certain animal diseases. Midichloriaceae have been found also in protists like ciliates and amoebae. The present work describes a new bacterial endosymbiont, "Candidatus Fokinia solitaria", retrieved from three different strains of a novel Paramecium species isolated from a wastewater treatment plant in Rio de Janeiro (Brazil. Symbionts were characterized through the full-cycle rRNA approach: SSU rRNA gene sequencing and fluorescence in situ hybridization (FISH with three species-specific oligonucleotide probes. In electron micrographs, the tiny rod-shaped endosymbionts (1.2 x 0.25-0.35 μm in size were not surrounded by a symbiontophorous vacuole and were located in the peripheral host cytoplasm, stratified in the host cortex in between the trichocysts or just below them. Frequently, they occurred inside autolysosomes. Phylogenetic analyses of Midichloriaceae apparently show different evolutionary pathways within the family. Some genera, such as "Ca. Midichloria" and "Ca. Lariskella", have been retrieved frequently and independently in different hosts and environmental surveys. On the contrary, others, such as Lyticum, "Ca. Anadelfobacter", "Ca. Defluviella" and the presently described "Ca. Fokinia solitaria", have been found only occasionally and associated to specific host species. These last are the only representatives in their own branches thus far. Present data do not allow to infer whether these genera, which we named "stand-alone lineages", are an indication of poorly sampled organisms, thus underrepresented in GenBank, or represent fast evolving, highly adapted evolutionary lineages.

  3. Study on the optimization of stand-alone type photovoltaic systems. 2

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Man Geun; Song, Jin Soo; Kim, Boo ho; Park, I June; Jung, Meung Woong; Yoo, Kyun Joung; Kim, Hong Woo [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

    1995-12-01

    The objectives of this study are to make a maximization of the operating efficiency of photovoltaic power systems, to improve stand- align PV systems design, technical operation and system analysis, and to promote technical cooperation of mutual interest in the area of IEA/PVPS program. This study aims to investigating the problems of applied photovoltaic power systems currently in operation to improve a system design, seeking remedies of individual PVPS applications to improve the system efficiency and reliability and to raise the system economics, and reporting the international movements of PV system dissemination and technical cooperation for developing countries. For the purpose of this works 1) Investigations of applications of existing photovoltaic power systems: - Photovoltaic electric sources used for expressway lamps - Optimum design of solar light with low pressure sodium lamps under 8 hours lighting a day at night by program-able electronic timer. 2) Comparative analyses of Marado PV system and propose a new reliable PV-diesel hybrid system and high efficiency operations. 3) Overall review of Hahwado 60 KWp PV system extending from 25 KWp and the remote monitoring systems for measurement of its operating results. 4) Introduction of IEA/PVPS international cooperating program, especially in task III for stand- alone PV systems and isolated islands and Exco meeting. As results, investigative findings of PVPS currently in operation and the work for improvement - Propose a prescription of Marado PV systems being blocked up by explosion of electrical demands from residence, parallel operational dual inverter with a big capacity. - There are shortage of solar generated power due to shortage of solar cell capacity that results in an increased operating time of diesel generator. Hence the insolation capacity of solar cell per household is continuously increased from the 0.5 KWp to 2 KWp in Hanwado island electrification.

  4. A Low-Power Wearable Stand-Alone Tongue Drive System for People With Severe Disabilities.

    Science.gov (United States)

    Jafari, Ali; Buswell, Nathanael; Ghovanloo, Maysam; Mohsenin, Tinoosh

    2018-02-01

    This paper presents a low-power stand-alone tongue drive system (sTDS) used for individuals with severe disabilities to potentially control their environment such as computer, smartphone, and wheelchair using their voluntary tongue movements. A low-power local processor is proposed, which can perform signal processing to convert raw magnetic sensor signals to user-defined commands, on the sTDS wearable headset, rather than sending all raw data out to a PC or smartphone. The proposed sTDS significantly reduces the transmitter power consumption and subsequently increases the battery life. Assuming the sTDS user issues one command every 20 ms, the proposed local processor reduces the data volume that needs to be wirelessly transmitted by a factor of 64, from 9.6 to 0.15 kb/s. The proposed processor consists of three main blocks: serial peripheral interface bus for receiving raw data from magnetic sensors, external magnetic interference attenuation to attenuate external magnetic field from the raw magnetic signal, and a machine learning classifier for command detection. A proof-of-concept prototype sTDS has been implemented with a low-power IGLOO-nano field programmable gate array (FPGA), bluetooth low energy, battery and magnetic sensors on a headset, and tested. At clock frequency of 20 MHz, the processor takes 6.6 s and consumes 27 nJ for detecting a command with a detection accuracy of 96.9%. To further reduce power consumption, an application-specified integrated circuit processor for the sTDS is implemented at the postlayout level in 65-nm CMOS technology with 1-V power supply, and it consumes 0.43 mW, which is 10 lower than FPGA power consumption and occupies an area of only 0.016 mm.

  5. Hydrogen-based energy storage unit for stand alone PV systems

    International Nuclear Information System (INIS)

    Labbe, J.

    2006-12-01

    Stand alone systems supplied only by a photovoltaic generator need an energy storage unit to be fully self sufficient. Lead acid batteries are commonly used to store energy because of their low cost, despite several operational constraints. A hydrogen-based energy storage unit (HESU) could be another candidate, including an electrolyser, a fuel cell and a hydrogen tank. However many efforts still need to be carried out for this technology to reach an industrial stage. In particular, market outlets must be clearly identified. The study of small stationary applications (few kW) is performed by numerical simulations. A simulator is developed in the Matlab/Simulink environment. It is mainly composed of a photovoltaic field and a storage unit (lead acid batteries, HESU, or hybrid storage HESU/batteries). The system component sizing is achieved in order to ensure the complete system autonomy over a whole year of operation. The simulator is tested with 160 load profiles (1 kW as a yearly mean value) and three locations (Algeria, France and Norway). Two coefficients are set in order to quantify the correlation between the power consumption of the end user and the renewable resource availability at both daily and yearly scales. Among the tested cases, a limit value of the yearly correlation coefficient came out, enabling to recommend the use of the most adapted storage to a considered case. There are cases for which using HESU instead of lead acid batteries can increase the system efficiency, decrease the size of the photovoltaic field and improve the exploitation of the renewable resource. In addition, hybridization of HESU with batteries always leads to system enhancements regarding its sizing and performance, with an efficiency increase by 10 to 40 % depending on the considered location. The good agreement between the simulation data and field data gathered on real systems enabled the validation of the models used in this study. (author)

  6. Probabilistic modelling and analysis of stand-alone hybrid power systems

    International Nuclear Information System (INIS)

    Lujano-Rojas, Juan M.; Dufo-López, Rodolfo; Bernal-Agustín, José L.

    2013-01-01

    As a part of the Hybrid Intelligent Algorithm, a model based on an ANN (artificial neural network) has been proposed in this paper to represent hybrid system behaviour considering the uncertainty related to wind speed and solar radiation, battery bank lifetime, and fuel prices. The Hybrid Intelligent Algorithm suggests a combination of probabilistic analysis based on a Monte Carlo simulation approach and artificial neural network training embedded in a genetic algorithm optimisation model. The installation of a typical hybrid system was analysed. Probabilistic analysis was used to generate an input–output dataset of 519 samples that was later used to train the ANNs to reduce the computational effort required. The generalisation ability of the ANNs was measured in terms of RMSE (Root Mean Square Error), MBE (Mean Bias Error), MAE (Mean Absolute Error), and R-squared estimators using another data group of 200 samples. The results obtained from the estimation of the expected energy not supplied, the probability of a determined reliability level, and the estimation of expected value of net present cost show that the presented model is able to represent the main characteristics of a typical hybrid power system under uncertain operating conditions. - Highlights: • This paper presents a probabilistic model for stand-alone hybrid power system. • The model considers the main sources of uncertainty related to renewable resources. • The Hybrid Intelligent Algorithm has been applied to represent hybrid system behaviour. • The installation of a typical hybrid system was analysed. • The results obtained from the study case validate the presented model

  7. Feasibility study and energy conversion analysis of stand-alone hybrid renewable energy system

    International Nuclear Information System (INIS)

    Baghdadi, Fazia; Mohammedi, Kamal; Diaf, Said; Behar, Omar

    2015-01-01

    Highlights: • Hybrid stand-alone wind–solar–fossil power system is analyzed. • Measurement data are used to evaluate system performance. • The proposed system can generate about 70% from renewables. • Such a hybrid plant is very promising for remote regions in Algeria. - Abstract: There is a great interest in the development of renewable power technologies in Algeria, and more particularly hybrid concept. The present paper has investigated the performance of hybrid PV–Wind–Diesel–Battery configuration based on hourly measurements of Adrar climate (southern Algeria). Data of global solar radiation, ambient temperature and wind speed for a period of one year have been used. Firstly, the proposed hybrid system has been optimized by means of HOMER software. The optimization process has been carried out taking into account renewable resources potential and energy demand; while maximizing renewable electricity use and fuel saving are the purpose. In the second step, a mathematical model has been developed to ensure efficient energy management on the basis of various operation strategies. The analysis has shown that renewable energy system (PV–Wind) is able to supply about 70% of the demand. Wind power has ranked first with 43% of the annual total electricity production followed by diesel generator (with 31%) while the remaining fraction is being to PV panels. In this context, 69% of the fossil fuel can be saved when using the proposed hybrid configuration instead of the diesel generators that are currently installed in most remote regions in Algeria. Such a concept is very promising to meet the focus of renewable energy program announced in 2011.

  8. Stand alone solution for generation and storage of hydrogen and electric energy

    International Nuclear Information System (INIS)

    Gany, Alon; Elitzur, Shani; Valery

    2015-01-01

    A novel method enabling safe, simple, and controllable production, storage, and use of hydrogen as well as compact electric energy storage and generation via hydrogen- oxygen fuel cells has been developed. The technology indicates, in our opinion, a significant milestone in the search for practical utilization of hydrogen as an alternative energy source. It consists of an original thermal-chemical treatment / activation of aluminum powders to react spontaneously with water to produce hydrogen at regular conditions according to the reaction Al+3H 2 O=Al (OH) 3 +3/2H 2 . Only about 1-2% of lithium, based activator is applied, and any type of water including tap water, sea water and waste water may be used, making the method attractive for variety of applications. 11% of hydrogen compared to the aluminum mass can be obtained, and our experiments reveal 90% reaction yield and more. The technology has a clear advantage over batteries, providing specific electric energy of over 2 kW h/kg Al, 5-10 times greater than that of commonly used lithium-ion batteries. Combined with a fuel cell it may be particularly beneficial for stand-alone electric power generators, where there is no access to the grid. Such applications include emergency generators (e.g., in hospitals), electricity backup systems, and power generation in remote communication posts. Automotive applications may be considered as well. The technology provides green electric energy and quiet operation as well as additional heat energy resulting mainly from the exothermic aluminum-water reaction. (full text)

  9. Stand-alone flat-plate photovoltaic power systems: System sizing and life-cycle costing methodology for Federal agencies

    Science.gov (United States)

    Borden, C. S.; Volkmer, K.; Cochrane, E. H.; Lawson, A. C.

    1984-01-01

    A simple methodology to estimate photovoltaic system size and life-cycle costs in stand-alone applications is presented. It is designed to assist engineers at Government agencies in determining the feasibility of using small stand-alone photovoltaic systems to supply ac or dc power to the load. Photovoltaic system design considerations are presented as well as the equations for sizing the flat-plate array and the battery storage to meet the required load. Cost effectiveness of a candidate photovoltaic system is based on comparison with the life-cycle cost of alternative systems. Examples of alternative systems addressed are batteries, diesel generators, the utility grid, and other renewable energy systems.

  10. prfectBLAST: a platform-independent portable front end for the command terminal BLAST+ stand-alone suite.

    Science.gov (United States)

    Santiago-Sotelo, Perfecto; Ramirez-Prado, Jorge Humberto

    2012-11-01

    prfectBLAST is a multiplatform graphical user interface (GUI) for the stand-alone BLAST+ suite of applications. It allows researchers to do nucleotide or amino acid sequence similarity searches against public (or user-customized) databases that are locally stored. It does not require any dependencies or installation and can be used from a portable flash drive. prfectBLAST is implemented in Java version 6 (SUN) and runs on all platforms that support Java and for which National Center for Biotechnology Information has made available stand-alone BLAST executables, including MS Windows, Mac OS X, and Linux. It is free and open source software, made available under the GNU General Public License version 3 (GPLv3) and can be downloaded at www.cicy.mx/sitios/jramirez or http://code.google.com/p/prfectblast/.

  11. Modeling, design and analysis of a stand-alone hybrid power generation system using solar/urine

    International Nuclear Information System (INIS)

    Wu, Wei; Zhou, Ya-Yan; Lin, Mu-Hsuan; Hwang, Jenn-Jiang

    2013-01-01

    Highlights: • The stand-alone hybrid power system is presented. • The urine-to-hydrogen processor is proposed. • Scenario analysis of the hybrid power dispatching and the urine/solar demands is investigated. • The design, modeling and optimization of the hybrid power system is addressed by Aspen Plus and Matlab. - Abstract: The urine turned to hydrogen as an energy conversion process is integrated into a stand-alone hybrid (PV/FC/battery) power generation system. The optimization and simulation of a new urine-to-hydrogen processor is evaluated in Aspen Plus environment. In our approach, the PV generator aims to reduce urine consumption and the lithium-ion battery can compensate the power gap due to the fuel processing delay. Based on prescribed patterns of solar irradiation and the daily load demand of a 30-persons classroom, scenario analyses of the hybrid power dispatching and operational feasibility is addressed

  12. Enhancement of a stand-alone photovoltaic system's performance: Reduction of soft and hard shading

    Energy Technology Data Exchange (ETDEWEB)

    Lamont, Lisa A.; El Chaar, Lana [Petroleum Institute, Electrical Engineering Department, P.O. Box 2533, Abu Dhabi (United Arab Emirates)

    2011-04-15

    A stand-alone photovoltaic (PV) system is the most promising solution to supply electric power to meet energy demand in isolated locations. This technology can offer an interesting alternative to other currently existing sources of energy. Due to space constraint in the remote offshore oil and gas industry, a stand-alone system is used for cathodic protection, telemetry and valve control. However in such an environment, dust accumulation and bird droppings have been critical issues to the operation of off-grid solar devices. These factors do not only reduce the available power of the modules but also makes the cost of solar devices ineffective since cleaning, especially on well-head towers, is very expensive due to the location. Hence this paper presents two technical solutions that have shown promising results in reducing the impact of these factors. (author)

  13. A review of three stand-alone topical thrombins for surgical hemostasis.

    Science.gov (United States)

    Cheng, Christine M; Meyer-Massetti, Carla; Kayser, Steven R

    2009-01-01

    Topical thrombins are active hemostatic agents that can be used to minimize blood loss during surgery. Before 2007, the only topical thrombins available were derived from bovine plasma. Antibody formation to bovine thrombin and/or factor V, with subsequent risk of cross-reactivity with human factor V, and hemorrhagic complications associated with human factor-V deficiencies have been described in case reports of surgeries in which bovine thrombins were used. This risk is now included in the boxed warning section of the bovine thrombin prescribing information. In 2007 and 2008, 2 new topical thrombins from nonbovine sources received approval for use from the US Food and Drug Administration. The 3 active topical thrombins that are currently marketed are bovine plasma-derived thrombin, human plasma-derived thrombin, and human recombinant thrombin. The purpose of this review was to evaluate the literature on the efficacy and safety of topical thrombins and discuss the pharmacoeconomic considerations associated with their use. PubMed, EMBASE, and International Pharmaceutical Abstracts were searched for relevant papers published in English through October 10,2008, using the terms thrombin, human recombinant thrombin, bovine thrombin, plasma derived thrombin, and topical thrombin. Manufacturer-provided materials were also reviewed. Abstracts and unpublished data, as well as evaluations of sealants, adhesives, glues, and other hemostats that contain thrombin mixed with fibrinogen and other clotting factors, were excluded. Four randomized, double-blind studies involving the active, stand-alone topical thrombins were found. The bovine thrombin involved in these studies was the predecessor to the currently marketed, highly purified bovine formulation. No studies comparing the human products, studies involving the highly purified bovine preparation, or placebo-controlled studies involving bovine thrombin were found. In a Phase III comparison of human recombinant thrombin and

  14. Control strategy of wind turbine based on permanent magnet synchronous generator and energy storage for stand-alone systems

    DEFF Research Database (Denmark)

    Deng, Fujin; Liu, Dong; Chen, Zhe

    2017-01-01

    This paper investigates a variable speed wind turbine based on permanent magnet synchronous generator and a full-scale power converter in a stand-alone system. An energy storage system(ESS) including battery and fuel cell-electrolyzer combination is connected to the DC link of the full-scale power...... converter through the power electronics interface. Wind is the primary power source of the system, the battery and FC-electrolyzer combination is used as a backup and a long-term storage system to provide or absorb power in the stand-alone system, respectively. In this paper, a control strategy is proposed...... for the operation of this variable speed wind turbine in a stand-alone system, where the generator-side converter and the ESS operate together to meet the demand of the loads. This control strategy is competent for supporting the variation of the loads or wind speed and limiting the DC-link voltage of the full...

  15. Sizing, techno-economic and generation management analysis of a stand alone photovoltaic power unit including storage devices

    International Nuclear Information System (INIS)

    Jallouli, Rihab; Krichen, Lotfi

    2012-01-01

    Due to the mismatch between the load demand and the intermittent solar energy, a stand-alone photovoltaic-hydrogen system and an optimal control scheme are designed to maintain the high system efficiency. Based on meteorological and the load demand data, a system sizing technique is proposed to establish the minimum capacity of the system components, which are a photovoltaic (PV) panel, a proton exchange membrane fuel cell (PEMFC), a battery bank and an alkaline electrolyzer (Elz). An accurate energy management scheme that is utilized during power transfer is proposed to meet the economic requirements. Case studies are used to verify the efficiency of the energy management strategy and system sizing technique. Simulation results illustrate a simple solution to the design and processing of stand-alone PV-hydrogen (PV-H 2 ) systems. -- Highlights: ► We study a stand alone PV-hydrogen system comprising renewable devices. ► A PV generator, a battery bank, a fuel cell and an electrolyzer are modeled. ► Power management taking into account the economic arrangement and the operating conditions to ensure energy availability is proposed.

  16. Optimum autonomous stand-alone photovoltaic system design on the basis of energy pay-back analysis

    International Nuclear Information System (INIS)

    Kaldellis, J.K.; Zafirakis, D.; Kondili, E.

    2009-01-01

    Stand-alone photovoltaic (PV) systems comprise one of the most promising electrification solutions for covering the demand of remote consumers. However, such systems are strongly questioned due to extreme life-cycle (LC) energy requirements. For similar installations to be considered as environmentally sustainable, their LC energy content must be compensated by the respective useful energy production, i.e. their energy pay-back period (EPBP) should be found less than their service period. In this context, an optimum sizing methodology is currently developed, based on the criterion of minimum embodied energy. Various energy autonomous stand-alone PV-lead-acid battery systems are examined and two different cases are investigated; a high solar potential area and a medium solar potential area. By considering that the PV-battery (PV-Bat) system's useful energy production is equal to the remote consumer's electricity consumption, optimum cadmium telluride (CdTe) based systems yield the minimum EPBP (15 years). If achieving to exploit the net PV energy production however, the EPBP is found less than 20 years for all PV types. Finally, the most interesting finding concerns the fact that in all cases examined the contribution of the battery component exceeds 27% of the system LC energy requirements, reflecting the difference between grid-connected and stand-alone configurations.

  17. A Case Study of Control and Improved Simplified Swarm Optimization for Economic Dispatch of a Stand-Alone Modular Microgrid

    Directory of Open Access Journals (Sweden)

    Xianyong Zhang

    2018-03-01

    Full Text Available Due to the complex configuration and control framework, the conventional microgrid is not cost-effective for engineering applications with small or medium capacity. A stand-alone modular microgrid with separated AC bus and decentralized control strategy is proposed in this paper. Each module is a self-powered system, which consists of wind and solar power, a storage battery, load and three-port converter. The modules are interconnected by three-port converters to form the microgrid. Characteristics, operation principle, control of the modular microgrid and the three-port converter are analyzed in detail. Distributed storage batteries enable power exchanges among modules to enhance economic returns. Economic dispatch of the stand-alone modular microgrid is a mixed-integer programming problem. A day-ahead operation optimization model including fuel cost, battery operation cost, and power transmission cost is established. Because there are so many constraints, it is difficult to produce a feasible solution and even more difficult to have an improved solution. An improved simplified swarm optimization (iSSO method is therefore proposed. The iSSO scheme designs the new update mechanism and survival of the fittest policy. The experimental results from the demonstration project on DongAo Island reflect the effectiveness of the stand-alone modular microgrid and the economic dispatch strategy based on the iSSO method.

  18. A New Vector Control of Brushless Doubly-Fed Inductor Generator With Transient Current Compensation for Stand-Alone Power Generation Applications

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Yu, Kailiang

    2018-01-01

    The stand-alone brushless doubly-fed induction generator (BDFIG) with the conventional control strategies suffers heavily from poor dynamic performance especially under heavy load disturbance. This paper presents a new vector control strategy of BDFIG for stand-alone power generation applications...... control strategies, and the results verify the satisfactory dynamic performance of the proposed strategy....

  19. New control strategy of stand-alone brushless doubly-fed induction generator for supplying unbalanced loads in ship shaft power generation system

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Xiong, Fei

    2017-01-01

    The ship shaft power generation system based on a stand-alone brushless doubly-fed induction generator (BDFIG) have demonstrated excellent saving-energy performance. This paper presents a new control scheme of the stand-alone BDFIG for supplying unbalanced loads in the ship shaft power generation...

  20. Methanol production via pressurized entrained flow biomass gasification – Techno-economic comparison of integrated vs. stand-alone production

    International Nuclear Information System (INIS)

    Andersson, Jim; Lundgren, Joakim; Marklund, Magnus

    2014-01-01

    The main objective with this work was to investigate techno-economically the opportunity for integrated gasification-based biomass-to-methanol production in an existing chemical pulp and paper mill. Three different system configurations using the pressurized entrained flow biomass gasification (PEBG) technology were studied, one stand-alone plant, one where the bark boiler in the mill was replaced by a PEBG unit and one with a co-integration of a black liquor gasifier operated in parallel with a PEBG unit. The cases were analysed in terms of overall energy efficiency (calculated as electricity-equivalents) and process economics. The economics was assessed under the current as well as possible future energy market conditions. An economic policy support was found to be necessary to make the methanol production competitive under all market scenarios. In a future energy market, integrating a PEBG unit to replace the bark boiler was the most beneficial case from an economic point of view. In this case the methanol production cost was reduced in the range of 11–18 Euro per MWh compared to the stand-alone case. The overall plant efficiency increased approximately 7%-units compared to the original operation of the mill and the non-integrated stand-alone case. In the case with co-integration of the two parallel gasifiers, an equal increase of the system efficiency was achieved, but the economic benefit was not as apparent. Under similar conditions as the current market and when methanol was sold to replace fossil gasoline, co-integration of the two parallel gasifiers was the best alternative based on received IRR. - Highlights: • Techno-economic results regarding integration of methanol synthesis processes in a pulp and paper mill are presented. • The overall energy efficiency increases in integrated methanol production systems compared to stand-alone production units. • The economics of the integrated system improves compared to stand-alone alternatives. • Tax

  1. Stand-Alone Personalized Normative Feedback for College Student Drinkers: A Meta-Analytic Review, 2004 to 2014.

    Directory of Open Access Journals (Sweden)

    Keri B Dotson

    Full Text Available Norms clarification has been identified as an effective component of college student drinking interventions, prompting research on norms clarification as a single-component intervention known as Personalized Normative Feedback (PNF. Previous reviews have examined PNF in combination with other components but not as a stand-alone intervention.To investigate the degree to which computer-delivered stand-alone personalized normative feedback interventions reduce alcohol consumption and alcohol-related harms among college students and to compare gender-neutral and gender-specific PNF.Electronic databases were searched systematically through November 2014. Reference lists were reviewed manually and forward and backward searches were conducted.Outcome studies that compared computer-delivered, stand-alone PNF intervention with an assessment only, attention-matched, or active treatment control and reported alcohol use and harms among college students.Between-group effect sizes were calculated as the standardized mean difference in change scores between treatment and control groups divided by pooled standard deviation. Within-group effect sizes were calculated as the raw mean difference between baseline and follow-up divided by pooled within-groups standard deviation.Eight studies (13 interventions with a total of 2,050 participants were included. Compared to control participants, students who received gender-neutral (dbetween = 0.291, 95% CI [0.159, 0.423] and gender-specific PNF (dbetween = 0.284, 95% CI [0.117, 0.451] reported greater reductions in drinking from baseline to follow-up. Students who received gender-neutral PNF reported 3.027 (95% CI [2.171, 3.882] fewer drinks per week at first follow-up and gender-specific PNF reported 3.089 (95% CI [0.992, 5.186] fewer drinks. Intervention effects were small for harms (dbetween = 0.157, 95% CI [0.037, 0.278].Computer-delivered PNF is an effective stand-alone approach for reducing college student

  2. Stand-Alone Personalized Normative Feedback for College Student Drinkers: A Meta-Analytic Review, 2004 to 2014.

    Science.gov (United States)

    Dotson, Keri B; Dunn, Michael E; Bowers, Clint A

    2015-01-01

    Norms clarification has been identified as an effective component of college student drinking interventions, prompting research on norms clarification as a single-component intervention known as Personalized Normative Feedback (PNF). Previous reviews have examined PNF in combination with other components but not as a stand-alone intervention. To investigate the degree to which computer-delivered stand-alone personalized normative feedback interventions reduce alcohol consumption and alcohol-related harms among college students and to compare gender-neutral and gender-specific PNF. Electronic databases were searched systematically through November 2014. Reference lists were reviewed manually and forward and backward searches were conducted. Outcome studies that compared computer-delivered, stand-alone PNF intervention with an assessment only, attention-matched, or active treatment control and reported alcohol use and harms among college students. Between-group effect sizes were calculated as the standardized mean difference in change scores between treatment and control groups divided by pooled standard deviation. Within-group effect sizes were calculated as the raw mean difference between baseline and follow-up divided by pooled within-groups standard deviation. Eight studies (13 interventions) with a total of 2,050 participants were included. Compared to control participants, students who received gender-neutral (dbetween = 0.291, 95% CI [0.159, 0.423]) and gender-specific PNF (dbetween = 0.284, 95% CI [0.117, 0.451]) reported greater reductions in drinking from baseline to follow-up. Students who received gender-neutral PNF reported 3.027 (95% CI [2.171, 3.882]) fewer drinks per week at first follow-up and gender-specific PNF reported 3.089 (95% CI [0.992, 5.186]) fewer drinks. Intervention effects were small for harms (dbetween = 0.157, 95% CI [0.037, 0.278]). Computer-delivered PNF is an effective stand-alone approach for reducing college student drinking and

  3. The da Vinci robotic surgical assisted anterior lumbar interbody fusion: technical development and case report.

    Science.gov (United States)

    Beutler, William J; Peppelman, Walter C; DiMarco, Luciano A

    2013-02-15

    Technique development to use the da Vince Robotic Surgical System for anterior lumbar interbody fusion at L5-S1 is detailed. A case report is also presented. To evaluate and develop the da Vinci robotic assisted laparoscopic anterior lumbar stand-alone interbody fusion procedure. Anterior lumbar interbody fusion is a common procedure associated with potential morbidity related to the surgical approach. The da Vinci robot provides intra-abdominal dissection and visualization advantages compared with the traditional open and laparoscopic approach. The surgical techniques for approach to the anterior lumbar spine using the da Vinci robot were developed and modified progressively beginning with operative models followed by placement of an interbody fusion cage in the living porcine model. Development continued to progress with placement of fusion cage in a human cadaver, completed first in the laboratory setting and then in the operating room. Finally, the first patient with fusion completed using the da Vinci robot-assisted approach is presented. The anterior transperitoneal approach to the lumbar spine is accomplished with enhanced visualization and dissection capability, with maintenance of pneumoperitoneum using the da Vinci robot. Blood loss is minimal. The visualization inside the disc space and surrounding structures was considered better than current open and laparoscopic techniques. The da Vinci robot Surgical System technique continues to develop and is now described for the transperitoneal approach to the anterior lumbar spine. 4.

  4. An optimized Fuzzy Logic Controller by Water Cycle Algorithm for power management of Stand-alone Hybrid Green Power generation

    International Nuclear Information System (INIS)

    Sarvi, Mohammad; Avanaki, Isa Nasiri

    2015-01-01

    Highlights: • A new method to improve the performance of renewable power management is proposed. • The proposed method is based on Fuzzy Logic optimized by the Water Cycle Algorithm. • The proposed method characteristics are compared with two other methods. • The comparisons confirm that the proposed method is robust and effectiveness one. - Abstract: This paper aims to improve the power management system of a Stand-alone Hybrid Green Power generation based on the Fuzzy Logic Controller optimized by the Water Cycle Algorithm. The proposed Stand-alone Hybrid Green Power consists of wind energy conversion and photovoltaic systems as primary power sources and a battery, fuel cell, and Electrolyzer as energy storage systems. Hydrogen is produced from surplus power generated by the wind energy conversion and photovoltaic systems of Stand-alone Hybrid Green Power and stored in the hydrogen storage tank for fuel cell later using when the power generated by primary sources is lower than load demand. The proposed optimized Fuzzy Logic Controller based power management system determines the power that is generated by fuel cell or use by Electrolyzer. In a hybrid system, operation and maintenance cost and reliability of the system are the important issues that should be considered in studies. In this regard, Water Cycle Algorithm is used to optimize membership functions in order to simultaneously minimize the Loss of Power Supply Probability and operation and maintenance. The results are compared with the particle swarm optimization and the un-optimized Fuzzy Logic Controller power management system to prove that the proposed method is robust and effective. Reduction in Loss of Power Supply Probability and operation and maintenance, are the most advantages of the proposed method. Moreover the level of the State of Charge of the battery in the proposed method is higher than other mentioned methods which leads to increase battery lifetime.

  5. Hierarchical energy management system for stand-alone hybrid system based on generation costs and cascade control

    International Nuclear Information System (INIS)

    Torreglosa, J.P.; García, P.; Fernández, L.M.; Jurado, F.

    2014-01-01

    Highlights: • We present an energy management system for a stand-alone WT/PV/hydrogen/battery hybrid system. • Hierarchical control composed by master and slave control strategies. • Control assures reliable electricity support for stand-alone applications subject to technical and economic criteria. - Abstract: This paper presents an energy management system (EMS) for stand-alone hybrid systems composed by photovoltaic (PV) solar panels and a wind turbine (WT) as primary energy sources and two energy storage systems, which are a hydrogen system and a battery. The hydrogen system is composed of fuel cell (FC), electrolyzer and hydrogen storage tank. The EMS is a hierarchical control composed by a master control strategy and a slave control strategy. On the one hand, the master control generates the reference powers to meet several premises (such as to satisfy the load power demand, and to maintain the hydrogen tank level and the state of charge (SOC) of the battery between their target margins), taking also into account economic aspects to discriminate between using the battery or hydrogen system. On the other hand, the slave control modifies the reference powers generated by the master control according to the energy sources dynamic limitations, and maintains the DC bus voltage at its reference value. The models, implemented in MATLAB-Simulink environment, have been developed from commercially available components. To check the viability of the proposed EMS, two kinds of simulations were carried out: (1) A long-term simulation of 25 years (expected lifetime of the system) with a sample time of one hour to validate the master control of the EMS; and (2) A short-term simulation with sudden net power variations to validate the slave control of the EMS

  6. Efficiency of the hybrid solar-wind systems for electricity supply to the stand-alone sites

    International Nuclear Information System (INIS)

    Abdullaev, D.A.; Isaev, R.I.

    2000-01-01

    The features of stand-alone sites and principles of their electricity supply is described there is going observation of the works about conditions of production and efficiency of using autonomy wind turbines and photovoltaics. Their unsufficiency is estimated. The advantages of hybrid systems and their realization schemes is described. The advantage of hybrid solar-wind Battery system (HSWBS) on the basis of own researches and the facts of other authors are given. The conception overall discounting cost is developed on HSWBS case. (Author)

  7. Evaluation of a proper controller performance for maximum-power point tracking of a stand-alone PV system

    Energy Technology Data Exchange (ETDEWEB)

    Nafeh, A.E.-S.A.; Fahmy, F.H. [Electronics Research Institute, Cairo (Egypt); El-Zahab, E.M.A. [Cairo University, Giza (Egypt). Faculty of Engineering

    2003-02-01

    In this paper the implementation of a suggested stand-alone PV system, for maximum-power point tracking (MPPT), is carried out. Also, this paper presents a comparative study, through experimental work, between the conventional PI controller and the fuzzy logic controller (FLC) under different atmospheric conditions. The implemented system with both the PI controller and the FLC gives a good maximum-power operation of the PV array, but the tracking capability for different optimum operating points is better and faster for the case of using the FLC compared to the case of using the PI controller. (author)

  8. Stand-alone core sensitivity and uncertainty analysis of ALFRED from Monte Carlo simulations

    International Nuclear Information System (INIS)

    Pérez-Valseca, A.-D.; Espinosa-Paredes, G.; François, J.L.; Vázquez Rodríguez, A.; Martín-del-Campo, C.

    2017-01-01

    Highlights: • Methodology based on Monte Carlo simulation. • Sensitivity analysis of Lead Fast Reactor (LFR). • Uncertainty and regression analysis of LFR. • 10% change in the core inlet flow, the response in thermal power change is 0.58%. • 2.5% change in the inlet lead temperature the response is 1.87% in power. - Abstract: The aim of this paper is the sensitivity and uncertainty analysis of a Lead-Cooled Fast Reactor (LFR) based on Monte Carlo simulation of sizes up to 2000. The methodology developed in this work considers the uncertainty of sensitivities and uncertainty of output variables due to a single-input-variable variation. The Advanced Lead fast Reactor European Demonstrator (ALFRED) is analyzed to determine the behavior of the essential parameters due to effects of mass flow and temperature of liquid lead. The ALFRED core mathematical model developed in this work is fully transient, which takes into account the heat transfer in an annular fuel pellet design, the thermo-fluid in the core, and the neutronic processes, which are modeled with point kinetic with feedback fuel temperature and expansion effects. The sensitivity evaluated in terms of the relative standard deviation (RSD) showed that for 10% change in the core inlet flow, the response in thermal power change is 0.58%, and for 2.5% change in the inlet lead temperature is 1.87%. The regression analysis with mass flow rate as the predictor variable showed statistically valid cubic correlations for neutron flux and linear relationship neutron flux as a function of the lead temperature. No statistically valid correlation was observed for the reactivity as a function of the mass flow rate and for the lead temperature. These correlations are useful for the study, analysis, and design of any LFR.

  9. GOssTo: a stand-alone application and a web tool for calculating semantic similarities on the Gene Ontology.

    Science.gov (United States)

    Caniza, Horacio; Romero, Alfonso E; Heron, Samuel; Yang, Haixuan; Devoto, Alessandra; Frasca, Marco; Mesiti, Marco; Valentini, Giorgio; Paccanaro, Alberto

    2014-08-01

    We present GOssTo, the Gene Ontology semantic similarity Tool, a user-friendly software system for calculating semantic similarities between gene products according to the Gene Ontology. GOssTo is bundled with six semantic similarity measures, including both term- and graph-based measures, and has extension capabilities to allow the user to add new similarities. Importantly, for any measure, GOssTo can also calculate the Random Walk Contribution that has been shown to greatly improve the accuracy of similarity measures. GOssTo is very fast, easy to use, and it allows the calculation of similarities on a genomic scale in a few minutes on a regular desktop machine. alberto@cs.rhul.ac.uk GOssTo is available both as a stand-alone application running on GNU/Linux, Windows and MacOS from www.paccanarolab.org/gossto and as a web application from www.paccanarolab.org/gosstoweb. The stand-alone application features a simple and concise command line interface for easy integration into high-throughput data processing pipelines. © The Author 2014. Published by Oxford University Press.

  10. SedInConnect: a stand-alone, free and open source tool for the assessment of sediment connectivity

    Science.gov (United States)

    Crema, Stefano; Cavalli, Marco

    2018-02-01

    There is a growing call, within the scientific community, for solid theoretic frameworks and usable indices/models to assess sediment connectivity. Connectivity plays a significant role in characterizing structural properties of the landscape and, when considered in combination with forcing processes (e.g., rainfall-runoff modelling), can represent a valuable analysis for an improved landscape management. In this work, the authors present the development and application of SedInConnect: a free, open source and stand-alone application for the computation of the Index of Connectivity (IC), as expressed in Cavalli et al. (2013) with the addition of specific innovative features. The tool is intended to have a wide variety of users, both from the scientific community and from the authorities involved in the environmental planning. Thanks to its open source nature, the tool can be adapted and/or integrated according to the users' requirements. Furthermore, presenting an easy-to-use interface and being a stand-alone application, the tool can help management experts in the quantitative assessment of sediment connectivity in the context of hazard and risk assessment. An application to a sample dataset and an overview on up-to-date applications of the approach and of the tool shows the development potential of such analyses. The modelled connectivity, in fact, appears suitable not only to characterize sediment dynamics at the catchment scale but also to integrate prediction models and as a tool for helping geomorphological interpretation.

  11. Improved double integral sliding mode MPPT controller based parameter estimation for a stand-alone photovoltaic system

    International Nuclear Information System (INIS)

    Chatrenour, Nasrin; Razmi, Hadi; Doagou-Mojarrad, Hasan

    2017-01-01

    Highlights: • IDISMC based MPPT algorithm is introduced. • Hurwitz stability theorem is used for switching surface coefficients computation. • GA approach is presented for parameter estimation of the stand-alone PV system. - Abstract: In this paper, an Improved Double Integral Sliding Mode MPPT Controller (IDISMC) for a stand-alone photovoltaic (PV) system is proposed. Performance of a sliding mode controller (SMC) is greatly influenced by the choice of the sliding surface. Switching surface coefficients were selected by the use of Hurwitz stability theorem. The IDISMC not only is robust against parametric and non-parametric uncertainties, but also has a very small steady-state error, thanks to the use of double integral of tracking voltage error in the definition of its sliding surface. For realistic simulation, Genetic Algorithm (GA) method was used to estimate parameters of solar panels model. The validity of the proposed double integral SMC in maximum power point tracking was approved by comparing the simulation results obtained for a sample PV system with the results of other methods.

  12. Economic and Environmental Assessment of a Renewable Stand-Alone Energy Supply System Using Multi-objective Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dohyun; Han, Seulki; Kim, Jiyong Kim [Incheon National University, Incheon (Korea, Republic of)

    2017-06-15

    This study aims to propose a new optimization-based approach for design and analysis of the stand-alone hybrid energy supply system using renewable energy sources (RES). In the energy supply system, we include multiple energy production technologies such as Photovoltaics (PV), Wind turbine, and fossil-fuel-based AC generator along with different types of energy storage and conversion technologies such as battery and inverter. We then select six different regions of Korea to represent various characteristics of different RES potentials and demand profiles. We finally designed and analyzed the optimal RES stand-alone energy supply system in the selected regions using multiobjective optimization (MOOP) technique, which includes two objective functions: the minimum cost and the minimum CO{sub 2} emission. In addition, we discussed the feasibility and expecting benefits of the systems by comparing to conventional systems of Korea. As a result, the region of the highest RES potential showed the possibility to remarkably reduce CO{sub 2} emissions compared to the conventional system. Besides, the levelized cost of electricity (LCOE) of the RES-based energy system is identified to be slightly higher than conventional energy system: 0.35 and 0.46 $/kWh, respectively. However, the total life-cycle emission of CO{sub 2} (LCECO{sub 2}) can be reduced up to 470 gCO{sub 2}/kWh from 490 gCO{sub 2}/kWh of the conventional systems.

  13. Comparison of pulp-mill-integrated hydrogen production from gasified black liquor with stand-alone production from gasified biomass

    International Nuclear Information System (INIS)

    Andersson, E.; Harvey, S.

    2007-01-01

    When gasified black liquor is used for hydrogen production, significant amounts of biomass must be imported. This paper compares two alternative options for producing hydrogen from biomass: (A) pulp-mill-integrated hydrogen production from gasified back liquor; and (B) stand-alone production of hydrogen from gasified biomass. The comparison assumes that the same amount of biomass that is imported in Alternative A is supplied to a stand-alone hydrogen production plant and that the gasified black liquor in Alternative B is used in a black liquor gasification combined cycle (BLGCC) CHP unit. The comparison is based upon equal amounts of black liquor fed to the gasifier, and identical steam and power requirements for the pulp mill. The two systems are compared on the basis of total CO 2 emission consequences, based upon different assumptions for the reference energy system that reflect different societal CO 2 emissions reduction target levels. Ambitions targets are expected to lead to a more CO 2 -lean reference energy system, in which case hydrogen production from gasified black liquor (Alternative A) is best from a CO 2 emissions' perspective, whereas with high CO 2 emissions associated with electricity production, hydrogen from gasified biomass and electricity from gasified black liquor (Alternative B) is preferable. (author)

  14. Multi-objective optimal planning of the stand-alone microgrid system based on different benefit subjects

    International Nuclear Information System (INIS)

    Guo, Li; Wang, Nan; Lu, Hai; Li, Xialin; Wang, Chengshan

    2016-01-01

    As an important means to realize the energetic complementarity and improve the efficiency of renewable resources, the stand-alone microgrid (SAMG) system gains attention increasingly, especially in islands and remote areas. In this paper, considering the interest conflict of the distribution company and the distributed generation owner, a new multi-objective optimal planning model is formulated for medium voltage SAMG. Besides, to avoid the power constraint of distributed generation (DG) once the over-limit voltage occurs, a novel two-step power dispatch control method including the voltage regulation strategy is proposed, in which the absorption of distributed power by energy storage system (ESS) and the reactive power adjustment though its power control system are used to regulate voltage. The goal of this paper is to search the Pareto-optimal front of the site and capacity of DG as well as the contract price between both parties, and thus can provide effective references for practical planning of SAMG. Considering the high cost of ESS, the investment analysis of ESS is also discussed in the paper. - Highlights: • A multi-objective planning model based on different benefit subjects is proposed. • A two-step power dispatch method including the voltage regulation is proposed. • The economical efficiency of the proposed model is analyzed. • The effective reference for the stand-alone microgrid planning is provided.

  15. A Control Approach and Supplementary Controllers for a Stand-Alone System with Predominance of Wind Generation

    Directory of Open Access Journals (Sweden)

    Tiago Lukasievicz

    2018-02-01

    Full Text Available This paper proposes a control approach and supplementary controllers for the operation of a hybrid stand-alone system composed of a wind generation unit and a conventional generation unit based on synchronous generator (CGU. The proposed controllers allow the islanded or isolated operation of small power systems with predominance of wind generation. As an advantage and a paradigm shift, the DC-link voltage of the wind unit is controlled by means of a conventional synchronous generator connected to the AC grid of the system. Two supplementary controllers, added to a diesel generator (DIG and to a DC dump load (DL, are proposed to control the DC-link voltage. The wind generation unit operates in V-f control mode and the DIG operates in PQ control mode, which allows the stand-alone system to operate either in wind-diesel (WD mode or in wind-only (WO mode. The strong influence of the wind turbine speed variations in the DC-link voltage is mitigated by a low-pass filter added to the speed control loop of the wind turbine. The proposed control approach does not require the use battery bank and ultra-capacitor to control the DC-link voltage in wind generation units based on fully rated converter.

  16. Optimization of the photovoltaic-hydrogen supply system of a stand-alone remote-telecom application

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Guillermo; Martinez, Graciano; Galvez, Jose L.; Cuevas, Raquel; Maellas, Jesus [National Institute for Aerospace Technology (INTA), Renewable Energy Department, Ctra. Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Gila, Raul; Bueno, Emilio [Polytechnical School - Alcala de Henares University, Electronics Department, Campus Universitario, Ctra. De Madrid-Barcelona Km 33.600, Alcala de Henares, Madrid (Spain)

    2009-07-15

    Hydrogen is considered as the optimal carrier for the surplus energy storage from renewable resources. Although hydrogen and its application in fuel cell is considered as a high-cost energy system, some cost-efficient solutions have been found for their use in stand-alone applications, which usually depend on the variability of renewable sources that have to be oversized in order to reduce their dependence on external energy sources. This paper shows the results from the simulation of several alternatives of introducing hydrogen technologies to increase the independence of a remote-telecom application fed by photovoltaic panels. Hydrogen is obtained by electrolysis and it is used in a fuel cell when the renewable energy source is not enough to maintain the stand-alone application. TRNSYS simulation environment has been used for evaluating the proposed alternatives. The results show that the best configuration option is that considering the use of hydrogen as a way to storage the surplus of radiation and the management system can vary the number of photovoltaic panels assigned to feed the hydrogen generation, the batteries or the telecom application. (author)

  17. Human microRNA target analysis and gene ontology clustering by GOmir, a novel stand-alone application.

    Science.gov (United States)

    Roubelakis, Maria G; Zotos, Pantelis; Papachristoudis, Georgios; Michalopoulos, Ioannis; Pappa, Kalliopi I; Anagnou, Nicholas P; Kossida, Sophia

    2009-06-16

    microRNAs (miRNAs) are single-stranded RNA molecules of about 20-23 nucleotides length found in a wide variety of organisms. miRNAs regulate gene expression, by interacting with target mRNAs at specific sites in order to induce cleavage of the message or inhibit translation. Predicting or verifying mRNA targets of specific miRNAs is a difficult process of great importance. GOmir is a novel stand-alone application consisting of two separate tools: JTarget and TAGGO. JTarget integrates miRNA target prediction and functional analysis by combining the predicted target genes from TargetScan, miRanda, RNAhybrid and PicTar computational tools as well as the experimentally supported targets from TarBase and also providing a full gene description and functional analysis for each target gene. On the other hand, TAGGO application is designed to automatically group gene ontology annotations, taking advantage of the Gene Ontology (GO), in order to extract the main attributes of sets of proteins. GOmir represents a new tool incorporating two separate Java applications integrated into one stand-alone Java application. GOmir (by using up to five different databases) introduces miRNA predicted targets accompanied by (a) full gene description, (b) functional analysis and (c) detailed gene ontology clustering. Additionally, a reverse search initiated by a potential target can also be conducted. GOmir can freely be downloaded BRFAA.

  18. Study on Soft Phase Locked Method to Solving the Synchronization Problem of Active Power Filter in Stand-alone Power Grid

    DEFF Research Database (Denmark)

    Zhuo, Fang; Wu, Longhui; Chen, Zhe

    2009-01-01

    on zero-cross detection can't work effectively in small rating stand-alone power grid. Then a soft phase locked loop with additional filter is proposed. It can lock the phase angle on to the positive sequence of fundamental voltage accurately and rapidly. It ensures the performance of APF applied...... in the small rating stand-alone power grid. Moreover, the soft phase locked loop is easy to be implemented in a Digital Signal Processor (DSP). Simulation and experimental results validate that the soft phase locked loop has satisfactory performance.......Traditional LC filters can't work stably in small rating stand-alone power grid. So active power filter (APF) is becoming an important tool to solve the power quality problem in small rating stand-alone power grid. In most current detection algorithm of APF, it needs a synchronizing signal. Firstly...

  19. Clinical and radiological outcome after anterior cervical discectomy and fusion with stand-alone empty polyetheretherketone (PEEK) cages.

    Science.gov (United States)

    Shiban, Ehab; Gapon, Karina; Wostrack, Maria; Meyer, Bernhard; Lehmberg, Jens

    2016-02-01

    To evaluate long-term results after one-, two-, and three-level anterior cervical discectomy and fusion (ACDF) with stand-alone empty polyetheretherketone (PEEK) cages. We performed a retrospective review of a consecutive patient cohort that underwent ACDF with stand-alone empty PEEK cages between 2007 and 2010 with a minimum follow-up of 12 months. Radiographic follow-up included static and flexion/extension radiographs. Changes in the operated segments were measured and compared to radiographs directly after surgery. Clinical outcome was evaluated by a physical examination, pain visual analog scale (VAS), and health-related quality of life (HRQL) using the EuroQOL questionnaire (EQ-5D). Analysis of associations between fusion, subsidence, cervical alignment, and clinical outcome parameters were performed. Of 407 consecutive cases, 318 met all inclusion criteria. Follow-up data were obtained from 265 (83 %) cases. The mean age at presentation was 55 years and 139 patients were male (52 %). In the sample, 127, 125, and 13 patients had one-, two-, and three-level surgeries, respectively; 132 (49 %) presented with spondylotic cervical myelopathy and 133 (50 %) with cervical radiculopathy. Fusion was achieved in 85, 95, and 94 % of segments in one-, two-, and three-level surgeries, respectively. Non-fusion was associated with higher VAS pain levels. Radiographic adjacent segment disease (ASD) was observed in 20, 29, and 15 % in one-, two-, and three-level surgeries, respectively. ASD was associated with lower HRQL. Subsidence was observed in 25, 27, and 15 % of segments in one-, two-, and three-level surgeries, respectively. However, this had no influence on clinical outcome. Follow-up operations for symptomatic adjacent disc disease and implant failure at index level were needed in 16 (6 %) and four (1.5 %) cases, respectively. Younger age was associated with better clinical outcome. Multilevel surgery favored better myelopathy outcomes and fusion reduced overall

  20. Online retrieval of patient information by asynchronous communication between general purpose computer and stand-alone personal computer

    International Nuclear Information System (INIS)

    Tsutsumi, Reiko; Takahashi, Kazuei; Sato, Toshiko; Komatani, Akio; Yamaguchi, Koichi

    1988-01-01

    Asynchronous communication was made between host (FACOM M-340) and personal computer (OLIBETTIE S-2250) to get patient's information required for RIA test registration. The retrieval system consists of a keyboad input of six numeric codes, patient's ID, and a real time reply containing six parameters for the patient. Their identified parameters are patient's name, sex, date of birth (include area), department, and out- or inpatient. Linking this program to RIA registration program for individual patient, then, operator can input name of RIA test requested. Our simple retrieval program made a useful data network between different types of host and stand-alone personal computers, and enabled us accurate and labor-saving registration for RIA test. (author)

  1. Integration of hydrogen energy technologies in stand-alone power systems analysis of the current potential for applications

    International Nuclear Information System (INIS)

    Zoulias, E.I.; Lymberopoulos, N.; Tsoutsos, T.; Glockner, R.; Mydske, H.J.; Vosseler, I.; Gavalda, O.; Taylor, P.

    2006-01-01

    The European study entitled: 'Market Potential Analysis for Introduction of Hydrogen Energy Technology in Stand-Alone Power Systems (H-SAPS)' aimed to establish a broad understanding of the market potential for H-SAPS and provide a basis for promoting in wide scale new technological applications. The scope of the study was limited to small and medium installations, up to a few hundred kW power rating and based on RE as the primary energy source. The potential for hydrogen technology in SAPS was investigated through an assessment of the technical potential for hydrogen, the market analysis and the evaluation of external factors. The results are mostly directed towards action by governments and the research community but also industry involvement is identified. The results include targeted market research, establishment of individual cost targets, regulatory changes to facilitate alternative grid solutions, information and capacity building, focused technology research and bridging the technology gaps. (author)

  2. A soil-canopy scheme for use in a numerical model of the atmosphere: 1D stand-alone model

    Science.gov (United States)

    Kowalczyk, E. A.; Garratt, J. R.; Krummel, P. B.

    We provide a detailed description of a soil-canopy scheme for use in the CSIRO general circulation models (GCMs) (CSIRO-4 and CSIRO-9), in the form of a one-dimensional stand-alone model. In addition, the paper documents the model's ability to simulate realistic surface fluxes by comparison with mesoscale model simulations (involving more sophisticated soil and boundary-layer treatments) and observations, and the diurnal range in surface quantities, including extreme maximum surface temperatures. The sensitivity of the model to values of the surface resistance is also quantified. The model represents phase 1 of a longer-term plan to improve the atmospheric boundary layer (ABL) and surface schemes in the CSIRO GCMs.

  3. Lateral Interbody Fusion for Treatment of Discogenic Low Back Pain: Minimally Invasive Surgical Techniques

    Directory of Open Access Journals (Sweden)

    Luis Marchi

    2012-01-01

    Full Text Available Low back pain is one of the most common ailments in the general population, which tends to increase in severity along with aging. While few patients have severe enough symptoms or underlying pathology to warrant surgical intervention, in those select cases treatment choices remain controversial and reimbursement is a substancial barrier to surgery. The object of this study was to examine outcomes of discogenic back pain without radiculopathy following minimally-invasive lateral interbody fusion. Twenty-two patients were treated at either one or two levels (28 total between L2 and 5. Discectomy and interbody fusion were performed using a minimallyinvasive retroperitoneal lateral transpsoas approach. Clinical and radiographic parameters were analyzed at standard pre- and postoperative intervals up to 24 months. Mean surgical duration was 72.1 minutes. Three patients underwent supplemental percutaneous pedicle screw instrumentation. Four (14.3% stand-alone levels experienced cage subsidence. Pain (VAS and disability (ODI improved markedly postoperatively and were maintained through 24 months. Segmental lordosis increased significantly and fusion was achieved in 93% of levels. In this series, isolated axial low back pain arising from degenerative disc disease was treated with minimally-invasive lateral interbody fusion in significant radiographic and clinical improvements, which were maintained through 24 months.

  4. Leadership in Dental Hygiene Degree Completion Programs: A Pilot Study Comparing Stand-Alone Leadership Courses and Leadership-Infused Curricula.

    Science.gov (United States)

    Smith, Michelle L; Gurenlian, JoAnn R; Freudenthal, Jacqueline J; Farnsworth, Tracy J

    2016-05-01

    The aim of this study was to define the extent to which leadership and leadership skills are taught in dental hygiene degree completion programs by comparing stand-alone leadership courses/hybrid programs with programs that infuse leadership skills throughout the curricula. The study involved a mixed-methods approach using qualitative and quantitative data. Semi-structured interviews were conducted with program directors and faculty members who teach a stand-alone leadership course, a hybrid program, or leadership-infused courses in these programs. A quantitative comparison of course syllabi determined differences in the extent of leadership content and experiences between stand-alone leadership courses and leadership-infused curricula. Of the 53 U.S. dental hygiene programs that offer degree completion programs, 49 met the inclusion criteria, and 19 programs provided course syllabi. Of the program directors and faculty members who teach a stand-alone leadership course or leadership-infused curriculum, 16 participated in the interview portion of the study. The results suggested that competencies related to leadership were not clearly defined or measurable in current teaching. Reported barriers to incorporating a stand-alone leadership course included overcrowded curricula, limited qualified faculty, and lack of resources. The findings of this study provide a synopsis of leadership content and gaps in leadership education for degree completion programs. Suggested changes included defining a need for leadership competencies and providing additional resources to educators such as courses provided by the American Dental Education Association and the American Dental Hygienists' Association.

  5. Stand-alone microgrids

    NARCIS (Netherlands)

    Bauer, P.; Weldemariam, L.E.; Raijen, E.

    2011-01-01

    Abstract- A hybrid power system (HPS) which consists of diesel Genset, PV -arrays and wind turbines with energy storing and power electronic devices is discussed in this paper. An inventory of different connection topologies is made for some of the sources that generate AC power and others that

  6. Epicardial, Biatrial Ablation With Integrated Uni-bipolar Radiofrequency Technology in Stand-alone Persistent Atrial Fibrillation.

    Science.gov (United States)

    Rosati, Fabrizio; Muneretto, Claudio; Merati, Elisa; Polvani, Gianluca; Moltrasio, Massimo; Tondo, Claudio; Curnis, Antonio; Cerini, Manuel; Metras, Alexandre; Bisleri, Gianluigi

    Although minimally invasive approaches for surgical treatment of stand-alone atrial fibrillation have gained popularity for the past decade, ablation technology and extensive lesion sets play a major role in the achievement of a successful procedure, especially in presence of persistent and long-standing persistent atrial fibrillation. We evaluated clinical outcomes after totally endoscopic biatrial epicardial ablation of persistent atrial fibrillation with a novel integrated uni-bipolar radiofrequency device. Forty-nine (49) consecutive patients with stand-alone atrial fibrillation underwent right-sided monolateral thoracoscopic surgical ablation with a novel integrated uni-bipolar radiofrequency energy delivery and temperature-controlled technology. Atrial fibrillation was persistent in 13 (26.5%) of 49 and long-standing persistent in 36 (73.5%) of 49 patients. Mean ± SD age was 60.6 ± 10.3 years. Median duration of atrial fibrillation was 74 months. Mean ± SD left atrial diameter was 44.7 ± 4.0 mm. Epicardial en bloc isolation of all pulmonary veins (box lesion) and additional ablation of the right atrial free wall was successfully performed via minimally invasive approach without any intraoperative and postoperative major complications. Intraoperative entrance and exit block was achieved in 77.5% (38/49) and 91.8% (45/49) of patients, respectively. Mean ± SD ablation time was 16.3 ± 4.8 minutes. No intensive care unit stay was required. Postoperative sinus rhythm was achieved in 93.8% (30/32) patients, and no pacemaker implantation was required. At 13 months, 87.7% (43/49) of patients were in sinus rhythm; 71.4% (35/49) were free from antiarrhythmic drugs and 75.5% (37/49) from oral anticoagulation. Integrated uni-bipolar radiofrequency ablation technology showed to be effective for the surgical treatment of atrial fibrillation with a total endoscopic approach. A versapolar suction device with extensive right-left atrial lesion set may further improve

  7. A Novel Method for Fast Configuration of Energy Storage Capacity in Stand-Alone and Grid-Connected Wind Energy Systems

    Directory of Open Access Journals (Sweden)

    Haixiang Zang

    2016-12-01

    Full Text Available In this paper, a novel method is proposed and applied to quickly calculate the capacity of energy storage for stand-alone and grid-connected wind energy systems, according to the discrete Fourier transform theory. Based on practical wind resource data and power data, which are derived from the American Wind Energy Technology Center and HOMER software separately, the energy storage capacity of a stand-alone wind energy system is investigated and calculated. Moreover, by applying the practical wind power data from a wind farm in Fujian Province, the energy storage capacity for a grid-connected wind system is discussed in this paper. This method can also be applied to determine the storage capacity of a stand-alone solar energy system with practical photovoltaic power data.

  8. Development of a Laser-Powered Dielectric Structure-Based Accelerator as a Stand-Alone Particle Source

    International Nuclear Information System (INIS)

    Yoder, R. B.; Travish, G.; Arab, E. R.; Fong, D.; Hoyer, Z.; Lacroix, U. H.; Vartanian, N.; Rosenzweig, J. B.

    2010-01-01

    An experimental program to develop and build a dielectric-based slab-symmetric structure (the micro-accelerator platform, or MAP) for generating and accelerating low-energy electrons is underway at UCLA and Manhattanville College. This optical acceleration structure is effectively a resonant cavity powered by a side-coupled laser, and has applications as a radiation source for medicine or industry. We present recent experimental and computational results on the accelerator, and progress toward its incorporation into a self-contained particle source. Such a particle source would incorporate a micron-scale electron emitter and a non-relativistic capture region to enable self-injection into the synchronous field within the accelerator. A prototype of the accelerator itself has been constructed from candidate dielectric materials using micromanufacturing techniques; the current status of the testing program is described. A novel electron emitter incorporating pyroelectric crystals with field-enhancing tips has been demonstrated to produce steady currents; the results are dependent on tip geometry, and appear suitable for injection into a microstructure. Extension of the MAP concept to non-relativistic velocities, as in the stand-alone source, requires a tapered structure that gives rise to numerous complications including beam defocusing and manufacturing challenges; approaches for addressing these complications are mentioned.

  9. Adaptive Artificial intelligence based fuzzy logic MPPTcontrol for stande-alone photovoltaic system under different atmospheric conditions

    Directory of Open Access Journals (Sweden)

    Zaghba Layachi

    2015-08-01

    Full Text Available there is an increased need for analysing the effect of atmospheric variables on photovoltaic (PV production and performance. The outputs from the different PV cells in different atmospheric conditions, such as irradiation and temperature , differ from each other evidencing knowledge deficiency in PV systems [14]. Maximum power point tracking (MPPT methods are used to maximize the PV array output power by tracking continuously the maximum power point (MPP. Among all MPPT methods existing in the literature, perturb and observe (P&O is the most commonly used for its simplicity and ease of implementation; however, it presents drawbacks such as slow response speed, oscillation around the MPP in steady state, and even tracking in wrong way under rapidly changing atmospheric conditions. In order to allow a functioning around the optimal point Mopt, we have inserted a DC-DC converter (Buck–Boost for a better matching between the PV and the load. This paper, we study the Maximum power point tracking using adaptive Intelligent fuzzy logic and conventional (P&O control for stande-alone photovoltaic Array system .In particular, the performances of the controllers are analyzed under variation weather conditions with are constant temperature and variable irradiation. The proposed system is simulated by using MATLAB-SIMULINK. According to the results, fuzzy logic controller has shown better performance during the optimization.

  10. Stand-alone power systems for the future: Optimal design, operation and control of solar-hydrogen energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Ulleberg, Oeystein

    1999-12-31

    This thesis gives a systematic review of the fundamentals of energy systems, the governing physical and chemical laws related to energy, inherent characteristics of energy system, and the availability of the earth`s energy. It shows clearly why solar-hydrogen systems are one of the most viable options for the future. The main subject discussed is the modelling of SAPS (Stand-Alone Power Systems), with focus on photovoltaic-hydrogen energy systems. Simulation models for a transient simulation program are developed for PV-H{sub 2} components, including models for photovoltaics, water electrolysis, hydrogen storage, fuel cells, and secondary batteries. A PV-H{sub 2} demonstration plant in Juelich, Germany, is studied as a reference plant and the models validated against data from this plant. Most of the models developed were found to be sufficiently accurate to perform short-term system simulations, while all were more than accurate enough to perform long-term simulations. Finally, the verified simulation models are used to find the optimal operation and control strategies of an existing PV-H{sub 2} system. The main conclusion is that the simulation methods can be successfully used to find optimal operation and control strategies for a system with fixed design, and similar methods could be used to find alternative system designs. 148 refs., 78 figs., 31 tabs.

  11. Power fluctuations suppression of stand-alone hybrid generation combining solar photovoltaic/wind turbine and fuel cell systems

    International Nuclear Information System (INIS)

    Ahmed, Nabil A.; Miyatake, Masafumi; Al-Othman, A.K.

    2008-01-01

    In this paper a hybrid energy system combining variable speed wind turbine, solar photovoltaic and fuel cell generation systems is presented to supply continuous power to residential power applications as stand-alone loads. The wind and photovoltaic systems are used as main energy sources while the fuel cell is used as secondary or back-up energy source. Three individual dc-dc boost converters are used to control the power flow to the load. A simple and cost effective control with dc-dc converters is used for maximum power point tracking and hence maximum power extracting from the wind turbine and the solar photovoltaic systems. The hybrid system is sized to power a typical 2 kW/150 V dc load as telecommunication power plants or ac residential power applications in isolated islands continuously throughout the year. The results show that even when the sun and wind are not available; the system is reliable and available and it can supply high-quality power to the load. The simulation results which proved the accuracy of the proposed controllers are given to demonstrate the availability of the proposed system in this paper. Also, a complete description of the management and control system is presented

  12. Comparison of Turkey’s Geographical Regions in terms of Stand-Alone PV System Design and Cost Parameters

    Directory of Open Access Journals (Sweden)

    Nevzat Onat

    2017-01-01

    Full Text Available Stand-alone photovoltaic (SAPV systems are widely used in rural areas where there is no national grid or as a precaution against power outages. In this study, technical and economic analysis of a SAPV system was carried out using meteorological data for 75 province centers in seven geographical regions of Turkey. Obtained results for each province center were separated by geographical area. The averages of the centers for each region are taken as output. A calculation algorithm based on MsExcel has been established for these operations. The analyses made with the developed algorithm are repeated for five different scenarios that they cover periods of time when a constant strong load is active for all seasons (winter, spring, summer, and autumn and all year round. The developed algorithm calculates the life-cycle cost, the unit energy cost, the electrical capacity utilization rate, the amount of generated/excess energy per month, the initial investment/replacement, and operating and maintenance (O&M costs of each element. As a result, geographical regions of Turkey are compared in terms of these outputs graphically. Further investigations may include the sale of excess energy generated, small-scale PV system cost factors parallel to the grid, and the effects of government incentives.

  13. A stand alone computer system to aid the development of mirror fusion test facility RF heating systems

    International Nuclear Information System (INIS)

    Thomas, R.A.

    1983-01-01

    The Mirror Fusion Test Facility (MFTF-B) control system architecture requires the Supervisory Control and Diagnostic System (SCDS) to communicate with a LSI-11 Local Control Computer (LCC) that in turn communicates via a fiber optic link to CAMAC based control hardware located near the machine. In many cases, the control hardware is very complex and requires a sizable development effort prior to being integrated into the overall MFTF-B system. One such effort was the development of the Electron Cyclotron Resonance Heating (ECRH) system. It became clear that a stand alone computer system was needed to simulate the functions of SCDS. This paper describes the hardware and software necessary to implement the SCDS Simulation Computer (SSC). It consists of a Digital Equipment Corporation (DEC) LSI-11 computer and a Winchester/Floppy disk operating under the DEC RT-11 operating system. All application software for MFTF-B is programmed in PASCAL, which allowed us to adapt procedures originally written for SCDS to the SSC. This nearly identical software interface means that software written during the equipment development will be useful to the SCDS programmers in the integration phase

  14. Stand-alone power systems for the future: Optimal design, operation and control of solar-hydrogen energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Ulleberg, Oeystein

    1998-12-31

    This thesis gives a systematic review of the fundamentals of energy systems, the governing physical and chemical laws related to energy, inherent characteristics of energy system, and the availability of the earth`s energy. It shows clearly why solar-hydrogen systems are one of the most viable options for the future. The main subject discussed is the modelling of SAPS (Stand-Alone Power Systems), with focus on photovoltaic-hydrogen energy systems. Simulation models for a transient simulation program are developed for PV-H{sub 2} components, including models for photovoltaics, water electrolysis, hydrogen storage, fuel cells, and secondary batteries. A PV-H{sub 2} demonstration plant in Juelich, Germany, is studied as a reference plant and the models validated against data from this plant. Most of the models developed were found to be sufficiently accurate to perform short-term system simulations, while all were more than accurate enough to perform long-term simulations. Finally, the verified simulation models are used to find the optimal operation and control strategies of an existing PV-H{sub 2} system. The main conclusion is that the simulation methods can be successfully used to find optimal operation and control strategies for a system with fixed design, and similar methods could be used to find alternative system designs. 148 refs., 78 figs., 31 tabs.

  15. Modeling and control design of a stand alone wind energy conversion system based on functional model predictive control

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, Ahmed M. [Beni-Suef University, Electrical Dept., Beni Suef (Egypt)

    2012-09-15

    This paper investigates the application of the model predictive control (MPC) approach to control the voltage and frequency of a stand alone wind generation system. This scheme consists of a wind turbine which drives an induction generator feeding an isolated load. A static VAR compensator is connected at the induction generator terminals to regulate the load voltage. The rotor speed, and thereby the load frequency are controlled via adjusting the mechanical power input using the blade pitch-angle. The MPC is used to calculate the optimal control actions including system constraints. To alleviate computational effort and to reduce numerical problems, particularly in large prediction horizon, an exponentially weighted functional model predictive control (FMPC) is employed. Digital simulations have been carried out in order to validate the effectiveness of the proposed scheme. The proposed controller has been tested through step changes in the wind speed and the load impedance. Simulation results show that adequate performance of the proposed wind energy scheme has been achieved. Moreover, this scheme is robust against the parameters variation and eliminates the influence of modeling and measurement errors. (orig.)

  16. Modeling and Experimental Test of Grid-Tied Photovoltaic Cell Emulating System in the Stand-alone Mode

    Directory of Open Access Journals (Sweden)

    Vu Minh Phap

    2017-06-01

    Full Text Available In recent decades, generation of electricity from solar arrays has been increased to meet the world's growing energy demand. However, the utilization rate of the power conditioner in the grid-tied solar power system is low because the operation of solar panels is dependent on sunlight. Thus, we studied the method that the small scale wind power generating system in size from a few hundred watts to two or three kilowatts can be connected to the grid-tied power conditioner of the solar power system for residential applications with low power ratings (single phase, size is limited to 10kW by emulating characteristic of the solar panel. In this paper, we introduce the application of the grid-tied PV cell emulating system in the stand-alone mode to improve the utilization rate of the power conditioner. The simulation and experimental test results verify that the PV cell emulating system can operate the power conditioner of the gridtied solar power system.

  17. Multi-Objective Optimal Design of Stand-Alone Hybrid Energy System Using Entropy Weight Method Based on HOMER

    Directory of Open Access Journals (Sweden)

    Jiaxin Lu

    2017-10-01

    Full Text Available Implementation of hybrid energy system (HES is generally considered as a promising way to satisfy the electrification requirements for remote areas. In the present study, a novel decision making methodology is proposed to identify the best compromise configuration of HES from a set of feasible combinations obtained from HOMER. For this purpose, a multi-objective function, which comprises four crucial and representative indices, is formulated by applying the weighted sum method. The entropy weight method is employed as a quantitative methodology for weighting factors calculation to enhance the objectivity of decision-making. Moreover, the optimal design of a stand-alone PV/wind/battery/diesel HES in Yongxing Island, China, is conducted as a case study to validate the effectiveness of the proposed method. Both the simulation and optimization results indicate that, the optimization method is able to identify the best trade-off configuration among system reliability, economy, practicability and environmental sustainability. Several useful conclusions are given by analyzing the operation of the best configuration.

  18. Techno-economic analysis of stand-alone photovoltaic/wind/battery/hydrogen systems for very small-scale applications

    Directory of Open Access Journals (Sweden)

    Stojković Saša M.

    2016-01-01

    Full Text Available The paper presents the results of a technical and economic analysis of three stand-alone hybrid power systems based on renewable energy sources which supply a specific group of low-power consumers. This particular case includes measuring sensors and obstacle lights on a meteorological mast for wind measurements requiring an uninterrupted power supply in cold climate conditions. Although these low-power (100 W measuring sensors and obstacle lights use little energy, their energy consumption is not the same as the available solar energy obtained on a daily or seasonal basis. In the paper, complementarity of renewable energy sources was analysed, as well as one of short-term lead-acid battery-based storage and seasonal, hydrogen-based (electrolyser, H2 tank, and fuel cells storage. These relatively complex power systems were proposed earlier for high-power consumers only, while this study specifically highlights the role of the hydrogen system for supplying low-power consumers. The analysis employed a numerical simulation method using the HOMER software tool. The results of the analysis suggest that solar and wind-solar systems, which involve meteorological conditions as referred to in this paper, include a relatively large number of lead-acid batteries. Additionally, the analysis suggests that the use of hydrogen power systems for supplying low power-consumers is entirely justifiable, as it significantly reduces the number of batteries (two at minimum in this particular case. It was shown that the increase in costs induced by the hydrogen system is acceptable.

  19. Energetic and financial investigation of a stand-alone solar-thermal Organic Rankine Cycle power plant

    International Nuclear Information System (INIS)

    Tzivanidis, Christos; Bellos, Evangelos; Antonopoulos, Kimon A.

    2016-01-01

    Highlights: • A stand-alone solar driven Organic Rankine Cycle is optimized parametrically. • The system is optimized energetically and financially. • Nine working fluids are tested with cyclohexane to be the most suitable. • A collecting area of 25,000 m"2 parabolic trough collectors is the optimum solution. • The maximum IRR is 13.46% and the payback period is about 9 years. - Abstract: The use of solar thermal energy for electricity production is a clean and sustainable way to cover the increasing energy needs of our society. The most mature technology for capturing solar energy in high temperature levels is the parabolic trough collectors (PTC). In this study, an Organic Rankine Cycle (ORC) coupled with PTC is analyzed parametrically in order to be optimized financially and energetically. The first step is the thermodynamic investigation of the ORC by using various working fluids. The second step is the energetic and financial investigation of the total system which includes the solar field, the storage tank and the ORC module. By testing many combinations of collecting areas and storage tank volumes, finally cyclohexane proved to be the most suitable working fluid for producing 1 MW_e_l with PTC. Specifically, in the optimum situation a solar field of 25,000 m"2 with storage tank of about 300 m"3 leads to a payback period of 9 years and to an internal rate of return (IRR) equal to 13.46%. Moreover, an economic comparison for different commercial collectors is presented, with Eurotrough ET-150 being the financially optimum solution for this case study.

  20. An adaptive artificial neural network model for sizing stand-alone photovoltaic systems: Application for isolated sites in Algeria

    International Nuclear Information System (INIS)

    Mellit, A.; Benghanem, M.; Hadj Arab, A.; Guessoum, G.

    2004-07-01

    In this paper we investigate, by using an adaptive Artificial Neural Network (ANN), in order to find a suitable model for sizing Stand-Alone Photovoltaic (SAPV) systems, based on a minimum of input data. This model combines Radial Basis Function (RBF) network and Infinite Impulse Response (IIR) filter in order to accelerate the convergence of the network. For the sizing of a photovoltaic (PV) system, we need to determine the optimal sizing coefficients (K PV , K B . These coefficients allow us to determine the number of solar panels and storage batteries necessary to satisfy a given consumption, especially in isolated sites where the global solar radiation data is not always available and which are considered the most important parameters for sizing a PV system. Obtained results by classical models (analytical, numerical, analytical- numerical, B-spline function) and new models like feed-forward (MLP), radial basis function (RBF), MLP-IIR and RBF-IIR have been compared with experimental sizing coefficients in order to illustrate the accuracy of the results of the new developed model. This model has been trained by using 200 known optimal sizing coefficients corresponding to 200 locations in Algeria. In this way, the adaptive model was trained to accept and even handle a number of unusual cases, the unknown validation sizing coefficients set produced very set accurate estimation and a correlation coefficient of 98% was obtained between the calculated and that estimated by the RBF-IIR model. This result indicates that the proposed method can be successfully used for the estimation of optimal sizing coefficients of SAPV systems for any locations in Algeria, but the methodology can be generalized using different locations over the world. (author)

  1. System dynamic model and charging control of lead-acid battery for stand-alone solar PV system

    KAUST Repository

    Huang, B.J.

    2010-05-01

    The lead-acid battery which is widely used in stand-alone solar system is easily damaged by a poor charging control which causes overcharging. The battery charging control is thus usually designed to stop charging after the overcharge point. This will reduce the storage energy capacity and reduce the service time in electricity supply. The design of charging control system however requires a good understanding of the system dynamic behaviour of the battery first. In the present study, a first-order system dynamics model of lead-acid battery at different operating points near the overcharge voltage was derived experimentally, from which a charging control system based on PI algorithm was developed using PWM charging technique. The feedback control system for battery charging after the overcharge point (14 V) was designed to compromise between the set-point response and the disturbance rejection. The experimental results show that the control system can suppress the battery voltage overshoot within 0.1 V when the solar irradiation is suddenly changed from 337 to 843 W/m2. A long-term outdoor test for a solar LED lighting system shows that the battery voltage never exceeded 14.1 V for the set point 14 V and the control system can prevent the battery from overcharging. The test result also indicates that the control system is able to increase the charged energy by 78%, as compared to the case that the charging stops after the overcharge point (14 V). © 2010 Elsevier Ltd. All rights reserved.

  2. Stand-alone front-end system for high- frequency, high-frame-rate coded excitation ultrasonic imaging.

    Science.gov (United States)

    Park, Jinhyoung; Hu, Changhong; Shung, K Kirk

    2011-12-01

    A stand-alone front-end system for high-frequency coded excitation imaging was implemented to achieve a wider dynamic range. The system included an arbitrary waveform amplifier, an arbitrary waveform generator, an analog receiver, a motor position interpreter, a motor controller and power supplies. The digitized arbitrary waveforms at a sampling rate of 150 MHz could be programmed and converted to an analog signal. The pulse was subsequently amplified to excite an ultrasound transducer, and the maximum output voltage level achieved was 120 V(pp). The bandwidth of the arbitrary waveform amplifier was from 1 to 70 MHz. The noise figure of the preamplifier was less than 7.7 dB and the bandwidth was 95 MHz. Phantoms and biological tissues were imaged at a frame rate as high as 68 frames per second (fps) to evaluate the performance of the system. During the measurement, 40-MHz lithium niobate (LiNbO(3)) single-element lightweight (<;0.28 g) transducers were utilized. The wire target measure- ment showed that the -6-dB axial resolution of a chirp-coded excitation was 50 μm and lateral resolution was 120 μm. The echo signal-to-noise ratios were found to be 54 and 65 dB for the short burst and coded excitation, respectively. The contrast resolution in a sphere phantom study was estimated to be 24 dB for the chirp-coded excitation and 15 dB for the short burst modes. In an in vivo study, zebrafish and mouse hearts were imaged. Boundaries of the zebrafish heart in the image could be differentiated because of the low-noise operation of the implemented system. In mouse heart images, valves and chambers could be readily visualized with the coded excitation.

  3. Post-processing in cardiovascular computed tomography. Performance of a client server solution versus a stand-alone solution

    International Nuclear Information System (INIS)

    Luecke, C.; Foldyna, B.; Andres, C.; Grothoff, M.; Nitzsche, S.; Gutberlet, M.; Lehmkuhl, L.; Boehmer-Lasthaus, S.

    2014-01-01

    Purpose: To compare the performance of server-based (CSS) versus stand-alone post-processing software (ES) for the evaluation of cardiovascular CT examinations (cvCT) and to determine the crucial steps. Data of 40 patients (20 patients for coronary artery evaluation and 20 patients prior to transcatheter aortic valve implantation [TAVI]) were evaluated by 5 radiologists with CSS and ES. Data acquisition was performed using a dual-source 128-row CT unit (SOMATOM Definition Flash, Siemens, Erlangen, Germany) and a 64-row CT unit (Brilliance 64, Philips, Hamburg, Germany). The following workflow was evaluated: Data loading, aorta and coronary segmentation, curved multiplanar reconstruction (cMPR) and 3 D volume rendering technique (3D-VRT), measuring of coronary artery stenosis and planimetry of the aortic annulus. The time requirement and subjective quality for the workflow were evaluated. The coronary arteries as well as the TAVI data could be evaluated significantly faster with CSS (5.5 ± 2.9 min and 8.2 ± 4.0 min, respectively) than with ES (13.9 ± 5.2 min and 15.2 ± 10.9 min, respectively, p = 0.01). Segmentation of the aorta (CSS: 1.9 ± 2.0 min, ES: 3.7 ± 3.3 min), generating cMPR of coronaries (CSS: 0.5 ± 0.2 min, ES: 5.1 ± 2.6 min), aorta and iliac vessels (CSS: 0.5 ± 0.4 min and 0.4 ± 0.4 min, respectively, ES: 1.6 ± 0.7 min and 2.8 ± 3 min, respectively) could be performed significantly faster with CSS than with ES with higher quality of cMPR, measuring of coronary stenosis and 3D-VRT (p < 0.05). Evaluation of cvCT can be accomplished significantly faster and better with CSS than with ES. The segmentation remains the most time-consuming workflow step, so optimization of segmentation algorithms could improve performance even further.

  4. A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages

    DEFF Research Database (Denmark)

    Liu, Xiong; Wang, Peng; Loh, Poh Chiang

    2011-01-01

    Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system......, which otherwise needs nine switches configuration, inclusive of one switch for boost converter, four switches for single-phase inverter and four switches for two DC/DC converters of battery and ultra-capacitor. It is well-known that a bulky DC-link capacitor is always required to absorb second......-order harmonic current caused by single-phase inverter. In the proposed compact topology, a small size DC-link capacitor can achieve the same function through charging/discharging control of ultra-capacitor to mitigate second-order ripple current. Simulation results are provided to validate the effectiveness...

  5. SoC-Based Output Voltage Control for BESS with a Lithium-Ion Battery in a Stand-Alone DC Microgrid

    Directory of Open Access Journals (Sweden)

    Seung-Yeong Yu

    2016-11-01

    Full Text Available This paper proposes a new DC output voltage control for a battery energy storage system (BESS with a lithium-ion battery based on the state of charge (SoC. The proposed control scheme was verified through computer simulations for a typical stand-alone DC microgrid, which consists of a BESS, photovoltaic (PV panel, engine generator (EG, and DC load. A scaled hardware prototype for a stand-alone DC microgrid was set up in the lab, in which the proposed control scheme was loaded in a DSP controller. The experimental results were compared with the simulation results for performance verification. The proposed control scheme provides relatively lower variation of the DC grid voltage than the conventional droop control.

  6. Systematic Multi-variable H-infinity Control Design for Primary Frequency Regulation in Stand-alone Microgrids with High Penetration of Renewable Energy Sources

    OpenAIRE

    Lam , Quang Linh; Bratcu , Antoneta Iuliana; Riu , Delphine

    2016-01-01

    International audience; In this paper, a systematic design of a robust multi-variable control structure for primary frequency regulation in microgrids with high rate of renewable source penetration is proposed. The considered microgrid represents a diesel-photovoltaic-supercapacitor hybrid power generation system operating in stand-alone mode. The proposed control structure relies on a two-level architecture: classical PI-based current tracking controllers are placed on the low control level ...

  7. Performance of a small stand alone photovoltaic-wind system at El Oyameyo D.F., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Juarez, A.; Campos, J. [Centro de Investigacion en Energia, UNAM, Mexico, D. F. (Mexico); Tiburcio Silver, A. [Instituto Tecnologico de Toluca-Division de Posgrado, Toluca (Mexico)

    1997-12-31

    El Oyameyo, is an ecological site located to the South-West of the Topilejo town, D.F., 19 degree 25` North latitude, 99 degree 5` West longitude and at an altitude of 3100 m. At present, there are 10 families living at this place. They have energy generators to produce their own electricity by means of solar or wind energy using photovoltaic (PV) technology and eolic systems, respectively. There are three different configurations of energy generators: DC regulated PV systems, AC regulated PV systems and one PV-Wind hybrid system. The electrical power installed for the stand alone PV systems are from 48 W-p up to 768 W-p range. Among these, there are 4 PV systems that are configurated in DC regulated systems, and other 6 are AC regulated systems. All these systems use lead-acid battery (scaled or vented) banks to store the energy produced daily by the systems. The PV-Wind hybrid system in formed, at present, by a 5.0 kW wind generator, a PV array of 768 W-p, a 37.8 kW-h storage battery bank and a 5.0 kW DC/AC inverter. In this work, we report the electricity generated, load pattern and overall system performance of the photovoltaic-wind hybrid system. The technical characteristics, energy test on the hybrid system and the experience obtained from energy handling and system maintenance for all the systems are presented. We found that all the systems had shown good performance and users` satisfaction. [Espanol] El Oyameyo es un lugar ecologico localizado al Sur-Oeste del pueblo de Topilejo, D. F., 19 grados 25` de latitud Norte 99 grados 5` de longitud Oeste y a una altitud de 3100m. Actualmente hay 10 familias viviendo en este lugar. Tienen generadores de energia para producir su propia electricidad mediante la energia solar y la del viento usando sistemas fotovoltaicos (FV) y sistemas eolicos, respectivamente. Hay tres diferentes configuraciones de generadores de energia: sistemas fotovoltaicos de CD regulados, sistemas fotovoltaicos de CA regulados y un sistema

  8. Design of a small scale stand-alone solar thermal co-generation plant for an isolated region in Egypt

    International Nuclear Information System (INIS)

    Abdelhady, Suzan; Borello, Domenico; Tortora, Eileen

    2014-01-01

    Highlights: • In the selected area, connection to the grid is very difficult and expensive. • The integrated unsteady CSP/ORC system, was modeled TRNSYS. • Assuming a CSP of 200,000 m 2 , 6 MW e and 21.5 MW th can be obtained. • The energy is sufficient to feed more than 3,300 rural users and two big factories. • PER = 1.43, LCOE = 1.25 USD/kW h and the GHG emissions are reduced of 7300 toe/year. - Abstract: Most of Egypt’s population is concentrated in the Nile Valley (5% of Egypt’s area), while the western desert occupies an area of 50% of the total area of Egypt with a small number of inhabitants. The New Valley is the largest governorates in Egypt which occupies 45.8% of the total area of the Country and 65% of the Western Desert and it is the least densely populated governorate in Egypt. However, New Valley has started to receive the migrated people from the Nile valley and Delta region and the demand for the energy is continuously increasing. However, the rural area in New Valley still suffers from lack of access to energy services. The very high transmission losses and costs are the main challenges for electrification in this area. Then, it is worth to investigate the opportunities for distributed energy generation. This area of Egypt receives some of the highest solar radiation in the world (up to 3000 kW h per square meters per year), making it a prime location for use of this resource. In this study, performance and economic assessment of a small scale stand-alone solar thermal co-generation plant using diathermic oil is presented. This configuration is considered as a promising and sustainable solution to provide electricity and heat to an isolated area satisfying the local loads. Parabolic trough plant has been modeled in TRNSYS simulation environment integrated with the Solar Thermal Electric Components (STEC) model library. Both solar and power cycle performances have been modeled based on the solar energy data of the plant site. The

  9. Performance of a small stand alone photovoltaic-wind system at El Oyameyo D.F., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Juarez, A; Campos, J [Centro de Investigacion en Energia, UNAM, Mexico, D. F. (Mexico); Tiburcio Silver, A [Instituto Tecnologico de Toluca-Division de Posgrado, Toluca (Mexico)

    1998-12-31

    El Oyameyo, is an ecological site located to the South-West of the Topilejo town, D.F., 19 degree 25` North latitude, 99 degree 5` West longitude and at an altitude of 3100 m. At present, there are 10 families living at this place. They have energy generators to produce their own electricity by means of solar or wind energy using photovoltaic (PV) technology and eolic systems, respectively. There are three different configurations of energy generators: DC regulated PV systems, AC regulated PV systems and one PV-Wind hybrid system. The electrical power installed for the stand alone PV systems are from 48 W-p up to 768 W-p range. Among these, there are 4 PV systems that are configurated in DC regulated systems, and other 6 are AC regulated systems. All these systems use lead-acid battery (scaled or vented) banks to store the energy produced daily by the systems. The PV-Wind hybrid system in formed, at present, by a 5.0 kW wind generator, a PV array of 768 W-p, a 37.8 kW-h storage battery bank and a 5.0 kW DC/AC inverter. In this work, we report the electricity generated, load pattern and overall system performance of the photovoltaic-wind hybrid system. The technical characteristics, energy test on the hybrid system and the experience obtained from energy handling and system maintenance for all the systems are presented. We found that all the systems had shown good performance and users` satisfaction. [Espanol] El Oyameyo es un lugar ecologico localizado al Sur-Oeste del pueblo de Topilejo, D. F., 19 grados 25` de latitud Norte 99 grados 5` de longitud Oeste y a una altitud de 3100m. Actualmente hay 10 familias viviendo en este lugar. Tienen generadores de energia para producir su propia electricidad mediante la energia solar y la del viento usando sistemas fotovoltaicos (FV) y sistemas eolicos, respectivamente. Hay tres diferentes configuraciones de generadores de energia: sistemas fotovoltaicos de CD regulados, sistemas fotovoltaicos de CA regulados y un sistema

  10. Biomechanics of an Expandable Lumbar Interbody Fusion Cage Deployed Through Transforaminal Approach

    Science.gov (United States)

    Mica, Michael Conti; Voronov, Leonard I.; Carandang, Gerard; Havey, Robert M.; Wojewnik, Bartosz

    2017-01-01

    Introduction A novel expandable lumbar interbody fusion cage has been developed which allows for a broad endplate footprint similar to an anterior lumbar interbody fusion (ALIF); however, it is deployed from a minimally invasive transforaminal unilateral approach. The perceived benefit is a stable circumferential fusion from a single approach that maintains the anterior tension band of the anterior longitudinal ligament. The purpose of this biomechanics laboratory study was to evaluate the biomechanical stability of an expandable lumbar interbody cage inserted using a transforaminal approach and deployed in situ compared to a traditional lumbar interbody cage inserted using an anterior approach (control device). Methods Twelve cadaveric spine specimens (L1-L5) were tested intact and after implantation of both the control and experimental devices in two (L2-L3 and L3-L4) segments of each specimen; the assignments of the control and experimental devices to these segments were alternated. Effect of supplemental pedicle screw-rod stabilization was also assessed. Moments were applied to the specimens in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). The effect of physiologic preload on construct stability was evaluated in FE. Segmental motions were measured using an optoelectronic motion measurement system. Results The deployable expendable TLIF cage and control devices significantly reduced FE motion with and without compressive preload when compared to the intact condition (p0.05). Adding bilateral pedicle screws resulted in further reduction of ROM for all loading modes compared to intact condition, with no statistical difference between the two constructs (p>0.05). Conclusions The ability of the deployable expendable interbody cage in reducing segmental motions was equivalent to the control cage when used as a stand-alone construct and also when supplemented with bilateral pedicle screw-rod instrumentation. The larger footprint of the fully

  11. Single anterior cervical discectomy and fusion (ACDF) using self- locking stand-alone polyetheretherketone (PEEK) cage: evaluation of pain and health-related quality of life.

    Science.gov (United States)

    Kapetanakis, Stylianos; Thomaidis, Tryfon; Charitoudis, George; Pavlidis, Pavlos; Theodosiadis, Panagiotis; Gkasdaris, Grigorios

    2017-09-01

    Anterior cervical discectomy and fusion (ACDF) constitutes the conventional treatment of cervical disc herniation due to degenerative disc disease (DDD). ACDF with plating presents a variety of complications postoperatively and stand-alone cages are thought to be a promising alternative. The aim of this study was firstly, to analyze prospectively collected data from a sample of patients treated with single ACDF using C-Plus self-locking stand-alone PEEK cage system, without the use of plates or screws, in order to evaluate pain levels of patients, utilizing Neck and Arm Pain scale as an expression of visual analogue scale (VAS). Secondly, we aimed to evaluate health-related quality of life, via the short-form 36 (SF-36) and Neck Disability Index (NDI). Thirty-six patients (19 male and 17 female) with mean age 49.6±7 years old who underwent successful single ACDF using self-locking stand-alone PEEK cage for symptomatic cervical DDD were selected for the study. Neck and Arm pain, as well as SF-36 and NDI were estimated preoperatively and 1, 3, 6, and 12 months postoperatively. Patients underwent preoperative and postoperative clinical, neurological and radiological evaluation. The clinical and radiological outcomes were satisfactory after a minimum 1-year follow-up. All results were statistically important (P<0.05), excluding improvement in NDI measured between 6 and 12 months. SF-36, Neck Pain, as well as Arm Pain featured gradual and constant improvement during follow-up, with best scores presenting at 12 months after surgery, while NDI reached its best at 6 months postoperatively. Generally, all scores showed improvement postoperatively during the different phases of the follow-up. Subsequently, ACDF using C-Plus cervical cage constitutes an effective method for cervical disc herniation treatment, in terms of postoperative improvement on pain levels and health-related quality of life and a safe alternative to the conventional method of treatment for cervical DDD.

  12. Clinician's perspectives of the relocation of a regional child and adolescent mental health service from co-located to stand alone premises.

    Science.gov (United States)

    Francis, K J; Boyd, C P; Sewell, J; Nurse, S

    2008-01-01

    Australia's National Mental Health Strategy's statement of rights and responsibilities states that children and adolescents admitted to a mental health facility or community program have the right to be separated from adult patients and provided with programs suited to their developmental needs. However, in rural Australia, where a lack of healthcare services, financial constraints, greater service delivery areas and fewer mental healthcare specialists represent the norm, Child and Adolescent Mental Health Services (CAMHS) are sometimes co-located with adult mental health services. The aim of the present study was to evaluate the impact of a recent relocation of a regional CAMHS in Victoria from co-located to stand alone premises. Six CAMHS clinicians who had experienced service delivery at a co-located setting and the current stand-alone CAMHS setting were interviewed about their perceptions of the impact of the relocation on service delivery. An exploratory interviewing methodology was utilized due to the lack of previous research in this area. Interview data were transcribed and analysed according to interpretative phenomenological analysis techniques. Findings indicated a perception that the relocation was positive for clients due to the family-friendly environment at the new setting and separation of CAMHS from adult psychiatric services. However, the impact of the relocation on clinicians was marked by a perceived loss of social capital from adult psychiatric service clinicians. These results provide increased understanding of the effects of service relocation and the influence of co-located versus stand-alone settings on mental health service delivery - an area where little prior research exists.

  13. Factors that can influence the economic feasibility of stand-alone and grid-connected photovoltaic systems: case studies using the software AVES-F

    International Nuclear Information System (INIS)

    Blasques, L.C.M.; Pinho, J.T.

    2004-01-01

    This paper presents case studies of economic feasibility of solar photovoltaic systems using the software AVES-F (Analysis of Economic Feasibility of Photovoltaic Systems), developed by the authors, considering cases of stand-alone and grid-connected systems. The software takes into account several factors that can influence the economic feasibility of these kind of systems, like load to be supplied, distance to the grid, the use regime of the system, applied subsidies and others. The main goal of this paper is to analyze some of these factors and to observe how they can affect the economics of PV systems for electricity generation. (authors)

  14. Risk factors for subsidence in anterior cervical fusion with stand-alone polyetheretherketone (PEEK) cages: a review of 82 cases and 182 levels.

    Science.gov (United States)

    Kao, Ting-Hsien; Wu, Chen-Hao; Chou, Yu-Ching; Chen, Hsien-Te; Chen, Wen-Hsien; Tsou, Hsi-Kai

    2014-10-01

    To determine risk factors for subsidence in patients treated with anterior cervical discectomy and fusion (ACDF) and stand-alone polyetheretherketone (PEEK) cages. Records of patients with degenerative spondylosis or traumatic disc herniation resulting in radiculopathy or myelopathy between C2 and C7 who underwent ACDF with stand-alone PEEK cages were retrospectively reviewed. Cages were filled with autogenous cancellous bone harvested from iliac crest or hydroxyapatite. Subsidence was defined as a decrease of 3 mm or more of anterior or posterior disc height from that measured on the postoperative radiograph. Eighty-two patients (32 males, 50 females; 182 treatment levels) were included in the analysis. Most patients had 1-2 treatment levels (62.2 %), and 37.8 % had 3-4 treatment levels. Treatment levels were from C2-7. Of the 82 patients, cage subsidence occurred in 31 patients, and at 39 treatment levels. Multivariable analysis showed that subsidence was more likely to occur in patients with more than two treatment levels, and more likely to occur at treatment levels C5-7 than at levels C2-5. Subsidence was not associated with postoperative alignment change but associated with more disc height change (relatively oversized cage). Subsidence is associated with a greater number of treatment levels, treatment at C5-7 and relatively oversized cage use.

  15. DCE-MRI of the breast in a stand-alone setting outside a complementary strategy - results of the TK-study

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Clemens G.; Krammer, J.; Wasser, K.; Schoenberg, S.O. [University Medical Centre Mannheim, Medical Faculty Mannheim-University of Heidelberg, Institute of Clinical Radiology and Nuclear Medicine, Mannheim (Germany); Reich, C.; Kaiser, W.A. [Friedrich-Schiller-University Hospital Jena, Institute of Diagnostic and Interventional Radiology I, Jena (Germany); Dietzel, M. [Friedrich-Alexander-University Hospital Erlangen-Nuernberg, Department of Neuroradiology, Erlangen (Germany); Baltzer, P.A.T. [Medical University Vienna, Institute of Radiology and Nuclear Medicine, Vienna (Austria)

    2015-06-01

    To evaluate the accuracy of MRI of the breast (DCE-MRI) in a stand-alone setting with extended indications. According to the inclusion criteria, breast specialists were invited to refer patients to our institution for DCE-MRI. Depending on the MR findings, patients received either a follow-up or biopsy. Between 04/2006 and 12/2011 a consecutive total of 1,488 women were prospectively examined. Of 1,488 included patients, 393 patients were lost to follow-up, 1,095 patients were evaluated. 124 patients were diagnosed with malignancy by DCE-MRI (76 TP, 48 FP, 971 TN, 0 FN cases). Positive cases were confirmed by histology, negative cases by MR follow-ups or patient questionnaires over the next 5 years in 1,737 cases (sensitivity 100 %; specificity 95.2 %; PPV 61.3 %; NPV 100 %; accuracy 95.5 %). For invasive cancers only (DCIS excluded), the results were 63 TP; 27 FP; 971 TP and 0 FN (sensitivity 100 %; specificity 97.2 %; PPV 70 %; NPV 100 %; accuracy 97.5 %). The DCE-MRI indications tested imply that negative results in DCE-MRI reliably exclude cancer. The results were achieved in a stand-alone setting (single modality diagnosis). However, these results are strongly dependent on reader experience and adequate technical standards as prerequisites for optimal diagnoses. (orig.)

  16. DCE-MRI of the breast in a stand-alone setting outside a complementary strategy - results of the TK-study

    International Nuclear Information System (INIS)

    Kaiser, Clemens G.; Krammer, J.; Wasser, K.; Schoenberg, S.O.; Reich, C.; Kaiser, W.A.; Dietzel, M.; Baltzer, P.A.T.

    2015-01-01

    To evaluate the accuracy of MRI of the breast (DCE-MRI) in a stand-alone setting with extended indications. According to the inclusion criteria, breast specialists were invited to refer patients to our institution for DCE-MRI. Depending on the MR findings, patients received either a follow-up or biopsy. Between 04/2006 and 12/2011 a consecutive total of 1,488 women were prospectively examined. Of 1,488 included patients, 393 patients were lost to follow-up, 1,095 patients were evaluated. 124 patients were diagnosed with malignancy by DCE-MRI (76 TP, 48 FP, 971 TN, 0 FN cases). Positive cases were confirmed by histology, negative cases by MR follow-ups or patient questionnaires over the next 5 years in 1,737 cases (sensitivity 100 %; specificity 95.2 %; PPV 61.3 %; NPV 100 %; accuracy 95.5 %). For invasive cancers only (DCIS excluded), the results were 63 TP; 27 FP; 971 TP and 0 FN (sensitivity 100 %; specificity 97.2 %; PPV 70 %; NPV 100 %; accuracy 97.5 %). The DCE-MRI indications tested imply that negative results in DCE-MRI reliably exclude cancer. The results were achieved in a stand-alone setting (single modality diagnosis). However, these results are strongly dependent on reader experience and adequate technical standards as prerequisites for optimal diagnoses. (orig.)

  17. Techno-economic assessment of FT unit for synthetic diesel production in existing stand-alone biomass gasification plant using process simulation tool

    DEFF Research Database (Denmark)

    Hunpinyo, Piyapong; Narataruksa, Phavanee; Tungkamani, Sabaithip

    2014-01-01

    For alternative thermo-chemical conversion process route via gasification, biomass can be gasified to produce syngas (mainly CO and H2). On more applications of utilization, syngas can be used to synthesize fuels through the catalytic process option for producing synthetic liquid fuels...... such as Fischer-Tropsch (FT) diesel. The embedding of the FT plant into the stand-alone based on power mode plants for production of a synthetic fuel is a promising practice, which requires an extensive adaptation of conventional techniques to the special chemical needs found in a gasified biomass. Because...... there are currently no plans to engage the FT process in Thailand, the authors have targeted that this work focus on improving the FT configurations in existing biomass gasification facilities (10 MWth). A process simulation model for calculating extended unit operations in a demonstrative context is designed...

  18. Effect of State Feedback Coupling and System Delays on the Transient Performance of Stand-Alone VSI with LC Output Filter

    DEFF Research Database (Denmark)

    Federico, de Bosio; de Sousa Ribeiro, Luiz Antonio; Freijedo Fernandez, Francisco Daniel

    2016-01-01

    The influence of state feedback coupling in the dynamics performance of power converters for stand-alone microgrids is investigated. Computation and PWM delays are the main factors that limit the achievable bandwidth of current regulators in digital implementations. In particular, the performance...... of state feedback decoupling is degraded because of these delays. Two decoupling techniques to improve the transient response of the system are investigated, named non-ideal and ideal capacitor voltage decoupling respectively. In particular, the latter solution consists in leading the capacitor voltage...... on the state feedback decoupling path in order to compensate for system delays. Practical implementation issues are discussed with reference to both the decoupling techniques. A design methodology for the voltage loop, that considers the closed loop transfer functions developed for the inner loop, is also...

  19. Synchronized Pulsed dc - dc Converter as Maximum Power Position Tracker with Wide Load and Insolation Variation for Stand Alone PV System

    International Nuclear Information System (INIS)

    Hardik, P. Desai; Ranjan Maheshwari

    2011-01-01

    This paper investigates the interest focused on employing parallel connected dc-dc converter with high tracking effectiveness under wide variation in environmental conditions (Insolation) and wide load variation. dc-dc converter is an essential part of the stand alone PV system. Paper also presents an approach on how duty cycle for maximum power position (MPP) is adjusted by taking care of varying load conditions and without iterative steps. Synchronized PWM pulses are employed for the converter. High tracking efficiency is achieved with continuous input and inductor current. In this approach, the converter can he utilized in buck as well in boost mode. The PV system simulation was verified and experimental results were in agreement to the presented scheme. (authors)

  20. Grid parity analysis of stand-alone hybrid microgrids: A comparative study of Germany, Pakistan, South Africa and the United States

    Science.gov (United States)

    Siddiqui, Jawad M.

    Grid parity for alternative energy resources occurs when the cost of electricity generated from the source is lower than or equal to the purchasing price of power from the electricity grid. This thesis aims to quantitatively analyze the evolution of hybrid stand-alone microgrids in the US, Germany, Pakistan and South Africa to determine grid parity for a solar PV/Diesel/Battery hybrid system. The Energy System Model (ESM) and NREL's Hybrid Optimization of Multiple Energy Resources (HOMER) software are used to simulate the microgrid operation and determine a Levelized Cost of Electricity (LCOE) figure for each location. This cost per kWh is then compared with two distinct estimates of future retail electricity prices at each location to determine grid parity points. Analysis results reveal that future estimates of LCOE for such hybrid stand-alone microgrids range within the 35-55 cents/kWh over the 25 year study period. Grid parity occurs earlier in locations with higher power prices or unreliable grids. For Pakistan grid parity is already here, while Germany hits parity between the years 2023-2029. Results for South Africa suggest a parity time range of the years 2040-2045. In the US, places with low grid prices do not hit parity during the study period. Sensitivity analysis results reveal the significant impact of financing and the cost of capital on these grid parity points, particularly in developing markets of Pakistan and South Africa. Overall, the study helps conclude that variations in energy markets may determine the fate of emerging energy technologies like microgrids. However, policy interventions have a significant impact on the final outcome, such as the grid parity in this case. Measures such as eliminating uncertainty in policies and improving financing can help these grids overcome barriers in developing economies, where they may find a greater use much earlier in time.

  1. Effects of ozone as a stand-alone and coagulation-aid treatment on the reduction of trihalomethanes precursors from high DOC and hardness water.

    Science.gov (United States)

    Sadrnourmohamadi, Mehrnaz; Gorczyca, Beata

    2015-04-15

    This study investigates the effect of ozone as a stand-alone and coagulation aid on the removal of dissolved organic carbon (DOC) from the water with a high level of DOC (13.8 mgL(-1)) and calcium hardness (270 mgL(-1)) CaCO3. Natural water collected from the Assiniboine River (Manitoba, Canada) was used in this study. Effectiveness of ozone treatment was evaluated by measurement of DOC, DOC fractions, UV254, and trihalomethane formation potential (THMFP). Additionally, zeta potential and dissolved calcium concentration were measured to discern the mechanism of ozone reactions. Results indicated that 0.8 mg O3/mg DOC ozone stand-alone can cause up to 86% UV254 reduction and up to 27% DOC reduction. DOC fractionation results showed that ozone can change the composition of DOC in the water samples, converting the hydrophobic fractions into hydrophilic ones and resulting in the reduction of THMFP. Also, ozone caused a decrease in particle stability and dissolved calcium concentration. These simultaneous ozonation effects caused improved water flocculation and enhanced removal of DOC. This resulted in reduction of the coagulant dosage when ozone doses higher than 0.2 mg O3/mg DOC were applied prior to coagulation with ferric sulfate. Also, pre-ozonation-coagulation process achieved preferential THMFP removal for all of the ozone doses tested (0-0.8 mg O3/mg DOC), leading to a lower specific THMFP in pre-ozonated-coagulated waters than in the corresponding ozonated waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Comparison of plate-cage construct and stand-alone anchored spacer in the surgical treatment of three-level cervical spondylotic myelopathy: a preliminary clinical study.

    Science.gov (United States)

    Shi, Sheng; Liu, Zu-De; Li, Xin-Feng; Qian, Lie; Zhong, Gui-Bin; Chen, Fang-Jing

    2015-09-01

    Although stand-alone cages were advocated to be superior to plate-cage construct (PCC) because of comparable clinical outcomes and fewer plate-related complications, cage dislocation and subsidence were frequently mentioned in multilevel fusion. There are some concerns about whether these issues can be effectively prevented in multilevel anterior cervical discectomy and fusion (ACDF) by stand-alone anchored spacer (SAAS). The aim was to compare clinical outcomes, radiologic parameters, and complications of PCC and SAAS in the treatment of three-level cervical spondylotic myelopathy (CSM). This was a retrospective comparative study. A total of 38 consecutive patients with three-level CSM (ACDF with PCC, 20 patients; ACDF with SAAS, 18 patients) were reviewed. Clinical outcomes were assessed using Japanese Orthopaedic Association and Neck Disability Index. The radiologic evaluations included cervical alignment (CA), segmental angle (SA), postoperative curvature loss (PCL), and incidence of subsidence. All the aforementioned parameters were compared before and after surgery between two groups. Besides, the aforementioned results were also compared between the two groups. The complications were also recorded. The mean follow-up period was 30.3 months. No significant differences were observed in clinical outcomes between the two groups (p>.05). Additionally, no significant differences existed in fusion rate between the two groups. There were significant differences in PCL of SA and CA and correction of SA between the two groups (pSAAS group, and the potential of SAAS to reduce the incidence of postoperative dysphagia was not proven. No other complications were observed in this study. In the surgical treatment of three-level CSM, PCC is superior to SAAS in correction and maintenance of SA and avoiding cage subsidence, although the technique of ACDF with SAAS yielded encouraging clinical outcomes and high fusion rate. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. PR2ALIGN: a stand-alone software program and a web-server for protein sequence alignment using weighted biochemical properties of amino acids.

    Science.gov (United States)

    Kuznetsov, Igor B; McDuffie, Michael

    2015-05-07

    Alignment of amino acid sequences is the main sequence comparison method used in computational molecular biology. The selection of the amino acid substitution matrix best suitable for a given alignment problem is one of the most important decisions the user has to make. In a conventional amino acid substitution matrix all elements are fixed and their values cannot be easily adjusted. Moreover, most existing amino acid substitution matrices account for the average (dis)similarities between amino acid types and do not distinguish the contribution of a specific biochemical property to these (dis)similarities. PR2ALIGN is a stand-alone software program and a web-server that provide the functionality for implementing flexible user-specified alignment scoring functions and aligning pairs of amino acid sequences based on the comparison of the profiles of biochemical properties of these sequences. Unlike the conventional sequence alignment methods that use 20x20 fixed amino acid substitution matrices, PR2ALIGN uses a set of weighted biochemical properties of amino acids to measure the distance between pairs of aligned residues and to find an optimal minimal distance global alignment. The user can provide any number of amino acid properties and specify a weight for each property. The higher the weight for a given property, the more this property affects the final alignment. We show that in many cases the approach implemented in PR2ALIGN produces better quality pair-wise alignments than the conventional matrix-based approach. PR2ALIGN will be helpful for researchers who wish to align amino acid sequences by using flexible user-specified alignment scoring functions based on the biochemical properties of amino acids instead of the amino acid substitution matrix. To the best of the authors' knowledge, there are no existing stand-alone software programs or web-servers analogous to PR2ALIGN. The software is freely available from http://pr2align.rit.albany.edu.

  4. A practical multi-objective design approach for optimum exhaust heat recovery from hybrid stand-alone PV-diesel power systems

    International Nuclear Information System (INIS)

    Yousefi, Moslem; Kim, Joong Hoon; Hooshyar, Danial; Yousefi, Milad; Sahari, Khairul Salleh Mohamed; Ahmad, Rodina Binti

    2017-01-01

    Highlights: • Heat recovery exchanger is designed based on practical conditions of a hybrid power system. • Off-the-grid electricity system modeling and analysis using micro-grid analysis software HOMER. • NSGA-II is used for the multi-objective design optimization task. • A new local search is proposed to incorporate the engineering knowledge in NSGA-II. • The proposed approach outperforms the existing ones. - Abstract: Integration of solar power and diesel generators (DGs) together with battery storage has proven to be an efficient choice for stand-alone power systems (SAPS). For higher energy efficiency, heat recovery from exhaust gas of the DG can also be employed to supply all or a portion of the thermal energy demand. Although the design of such heat recovery systems (HRSs) has been studied, the effect of solar power integration has not been taken into account. In this paper, a new approach for practical design of these systems based on varying engine loads is presented. Fast and elitist non-dominated sorting genetic algorithm (NSGA-II) equipped with a novel local search was used for the design process, considering conflicting objectives of annual energy recovery and total cost of the system, and six design variables. An integrated power system, designed for a remote SAPS, was used to evaluate the design approach. The optimum power supply system was first designed using the commercial software Hybrid Optimization of Multiple Energy Resources (HOMER), based on power demand and global solar energy in the region. Heat recovery design was based on the outcome of HOMER for DG hourly load, considering different power scenarios. The proposed approach improves the annual heat recovery of the PV/DG/battery system by 4%, PV/battery by 1.7%, and stand-alone DG by 1.8% when compared with a conventional design based on nominal DG load. The results prove that the proposed approach is effective and that load calculations should be taken into account prior to

  5. The Research on Second-Order ADRC Algorithm of Using Wind Turbine Virtual Inertia to Participate in Primary Frequency Regulation in a Small Stand-Alone Microgrid

    Directory of Open Access Journals (Sweden)

    Wang Yi

    2018-01-01

    Full Text Available In order to improve the transient stability of frequency in a small stand-alone microgrid (SSM, this paper takes a SSM composed of a direct-drive permanent magnet synchronous generator (D-PMSG and a micro gas turbine (MGT as the background and uses wind turbine generator (WTG virtual inertia (VI to participate in the primary (short-term system frequency regulation. First of all, this paper constructs a grid-connected model composed of a WTG and a MGT, analyzes the WTG virtual inertia frequency regulation mechanism, and explains the principle of proportional-differentiation (PD virtual inertia control (VIC and its shortcomings. Secondly, the paper introduces the structure principle of n-order active disturbance rejection control (ADRC and deduces the design process of second-order ADRC-VIC. Finally, through the simulation and experimental verification, comparing the frequency perturbation of without-VIC, PD-VIC, and ADRC-VIC, it is concluded that PD-VIC and ADRC-VIC both can use the WTG virtual inertia to participate in the primary frequency regulation. The frequency regulation effect of ADRC-VIC is better than PD-VIC, ADRC-VIC can extend the rotor speed recovery time and avoid overshoot, and its frequency fluctuation amplitude and settling time are obviously improved, and ADRC-VIC can effectively avoid the overshoot phenomenon of the MGT output power.

  6. Optimal Sizing of a Stand-Alone Hybrid Power System Based on Battery/Hydrogen with an Improved Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Weiqiang Dong

    2016-09-01

    Full Text Available A distributed power system with renewable energy sources is very popular in recent years due to the rapid depletion of conventional sources of energy. Reasonable sizing for such power systems could improve the power supply reliability and reduce the annual system cost. The goal of this work is to optimize the size of a stand-alone hybrid photovoltaic (PV/wind turbine (WT/battery (B/hydrogen system (a hybrid system based on battery and hydrogen (HS-BH for reliable and economic supply. Two objectives that take the minimum annual system cost and maximum system reliability described as the loss of power supply probability (LPSP have been addressed for sizing HS-BH from a more comprehensive perspective, considering the basic demand of load, the profit from hydrogen, which is produced by HS-BH, and an effective energy storage strategy. An improved ant colony optimization (ACO algorithm has been presented to solve the sizing problem of HS-BH. Finally, a simulation experiment has been done to demonstrate the developed results, in which some comparisons have been done to emphasize the advantage of HS-BH with the aid of data from an island of Zhejiang, China.

  7. Stand-Alone Containment Analysis of the Phébus FPT Tests with the ASTEC and the MELCOR Codes: The FPT-0 Test

    Directory of Open Access Journals (Sweden)

    Bruno Gonfiotti

    2017-01-01

    Full Text Available The integral Phébus tests were probably one of the most important experimental campaigns performed to investigate the progression of severe accidents in light water reactors. In these tests, the degradation of a PWR fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the results of such tests, numerical codes such as ASTEC and MELCOR have been developed to describe the evolution of a severe accident. After the termination of the experimental Phébus campaign, these two codes were furthermore expanded. Therefore, the aim of the present work is to reanalyze the first Phébus test (FPT-0 employing the updated ASTEC and MELCOR versions to ensure that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The analysis focuses on the stand-alone containment aspects of this test, and the paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products behavior. This paper is part of a series of publications covering the four executed Phébus tests employing a solid PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3.

  8. Development of Stand Alone Application Tool for Processing and Quality Measurement of Weld Imperfection Image Captured by μ-Focused Digital Radiography Using MATLAB- Based Graphical User Interface

    Directory of Open Access Journals (Sweden)

    PZ Nadila

    2012-12-01

    Full Text Available Digital radiography incresingly is being applied in the fabrication industry. Compared to film- based radiography, digitally radiographed images can be acquired with less time and fewer exposures. However, noises can simply occur on the digital image resulting in a low-quality result. Due to this and the system’s complexity, parameters’ sensitivity, and environmental effects, the results can be difficult to interpret, even for a radiographer. Therefore, the need of an application tool to improve and evaluate the image is becoming urgent. In this research, a user-friendly tool for image processing and image quality measurement was developed. The resulting tool contains important components needed by radiograph inspectors in analyzing defects and recording the results. This tool was written by using image processing and the graphical user interface development environment and compiler (GUIDE toolbox available in Matrix Laboratory (MATLAB R2008a. In image processing methods, contrast adjustment, and noise removal, edge detection was applied. In image quality measurement methods, mean square error (MSE, peak signal-to-noise ratio (PSNR, modulation transfer function (MTF, normalized signal-to-noise ratio (SNRnorm, sensitivity and unsharpness were used to measure the image quality. The graphical user interface (GUI wass then compiled to build a Windows, stand-alone application that enables this tool to be executed independently without the installation of MATLAB.

  9. Methodology for predicting sequences of mean monthly clearness index and daily solar radiation data in remote areas: Application for sizing a stand-alone PV system

    Energy Technology Data Exchange (ETDEWEB)

    Mellit, A. [Department of Electronics, Institute of Sciences Engineering, Centre University of Medea, Medea 26000 (Algeria); Department of Electronics, Faculty of Science Engineering, Blida University, Blida 09000 (Algeria); Kalogirou, S.A. [Higher Technical Institute, P.O. Box 20423, Nicosia 2152 (Cyprus); Shaari, S. [Faculty of Applied Sciences, Universiti Teknologi MARA 40450 Shah Alam, Selangor (Malaysia); Salhi, H. [Department of Electronics, Faculty of Science Engineering, Blida University, Blida 09000 (Algeria); Hadj Arab, A. [Development Centre of Renewable Energy (CDER), P.O. Box 62, Bouzareah, Algiers 16000 (Algeria); Departamento de Energias Renerables, CIEMAT, Arda Complutense, 22, Madrid 28040 (Spain)

    2008-07-15

    In this paper, a suitable adaptive neuro-fuzzy inference system (ANFIS) model is presented for estimating sequences of mean monthly clearness index (anti K{sub t}) and total solar radiation data in isolated sites based on geographical coordinates. The magnitude of solar radiation is the most important parameter for sizing photovoltaic (PV) systems. The ANFIS model is trained by using a multi-layer perceptron (MLP) based on fuzzy logic (FL) rules. The inputs of the ANFIS are the latitude, longitude, and altitude, while the outputs are the 12-values of mean monthly clearness index anti K{sub t}. These data have been collected from 60 locations in Algeria. The results show that the performance of the proposed approach in the prediction of mean monthly clearness index anti K{sub t} is favorably compared to the measured values. The root mean square error (RMSE) between measured and estimated values varies between 0.0215 and 0.0235 and the mean absolute percentage error (MAPE) is less than 2.2%. In addition, a comparison between the results obtained by the ANFIS model and artificial neural network (ANN) models, is presented in order to show the advantage of the proposed method. An example for sizing a stand-alone PV system is also presented. This technique has been applied to Algerian locations, but it can be generalized for any geographical position. It can also be used for estimating other meteorological parameters such as temperature, humidity and wind speed. (author)

  10. A Study on Electric Power Smoothing System for Lead-Acid Battery of Stand-Alone Natural Energy Power System Using EDLC

    Science.gov (United States)

    Jia, Yan; Shibata, Ryosuke; Yamamura, Naoki; Ishida, Muneaki

    To resolve energy shortage and global warming problem, renewable natural resource and its power system has been gradually generalizing. However, the power fluctuation suppressing in short period and the balance control of consumption and supply in long period are two of main problems that need to be resolved urgently in natural energy power system. In Stand-alone Natural Energy Power System (SNEPS) with power energy storage devices, power fluctuation in short period is one of the main reasons that recharge cycle times increase and lead-acid battery early failure. Hence, to prolong the service life of lead-acid battery and improve power quality through suppressing the power fluctuation, we proposed a method of electric power smoothing for lead-acid battery of SNEPS using bi-directional Buck/Boost converter and Electric Double Layer Capacitor (EDLC) in this paper. According to the test data of existing SNEPS, a power fluctuation condition is selected and as an example to analyze the validity of the proposed method. The analysis of frequency characteristics indicates the power fluctuation is suppressed a desired range in the target frequency region. The experimental results of confirmed the feasibility of the proposed system and the results well satisfy the requirement of system design.

  11. A case study of a typical 2.32 kW{sub P} stand-alone photovoltaic (SAPV) in composite climate of New Delhi (India)

    Energy Technology Data Exchange (ETDEWEB)

    Chel, Arvind; Tiwari, G.N. [Center for Energy Studies (CES), Indian Institute of Technology, Hauz Khas, New Delhi 110 016 (India)

    2011-04-15

    This paper presents rigorous experimental outdoor performance of a 2.32 kW{sub P} stand-alone photovoltaic (SAPV) system in New Delhi (India) for four weather types in each month such as clear, hazy, partially cloudy/foggy and fully cloudy/foggy weather conditions respectively. The daily power generated from the existing SAPV system was experimentally found in the range of 4-6 kW h/day depending on the prevailing sky conditions. The number of days and daily power generated corresponding to four weather types in each month were used to determine monthly and subsequently annual power generation from the existing SAPV system. There are three daily load profiles with and without earth to air heat exchanger suitable for three seasons like summer (3.75-6.15 kW h/day), winter (2.79-5.19 kW h/day) and rainy (3.75 kW h/day). The hourly efficiency of the SAPV system components are determined and presented in this paper. The life cycle cost (LCC) analysis for the existing typical SAPV system is carried out to determine unit cost of electricity. The effect of annual degradation rate of PV system efficiency is also presented in this paper. The energy production factor (EPF) and the energy payback time (EPBT) of the SAPV system was also determined and presented in this paper. (author)

  12. CRionScan: A stand-alone real time controller designed to perform ion beam imaging, dose controlled irradiation and proton beam writing

    Science.gov (United States)

    Daudin, L.; Barberet, Ph.; Serani, L.; Moretto, Ph.

    2013-07-01

    High resolution ion microbeams, usually used to perform elemental mapping, low dose targeted irradiation or ion beam lithography needs a very flexible beam control system. For this purpose, we have developed a dedicated system (called “CRionScan”), on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d'Ions en Région Aquitaine). It consists of a stand-alone real-time scanning and imaging instrument based on a Compact Reconfigurable Input/Output (Compact RIO) device from National Instruments™. It is based on a real-time controller, a Field Programmable Gate Array (FPGA), input/output modules and Ethernet connectivity. We have implemented a fast and deterministic beam scanning system interfaced with our commercial data acquisition system without any hardware development. CRionScan is built under LabVIEW™ and has been used on AIFIRA's nanobeam line since 2009 (Barberet et al., 2009, 2011) [1,2]. A Graphical User Interface (GUI) embedded in the Compact RIO as a web page is used to control the scanning parameters. In addition, a fast electrostatic beam blanking trigger has been included in the FPGA and high speed counters (15 MHz) have been implemented to perform dose controlled irradiation and on-line images on the GUI. Analog to Digital converters are used for the beam current measurement and in the near future for secondary electrons imaging. Other functionalities have been integrated in this controller like LED lighting using Pulse Width Modulation and a “NIM Wilkinson ADC” data acquisition.

  13. CRionScan: A stand-alone real time controller designed to perform ion beam imaging, dose controlled irradiation and proton beam writing

    Energy Technology Data Exchange (ETDEWEB)

    Daudin, L., E-mail: daudin@cenbg.in2p3.fr [Université Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Barberet, Ph.; Serani, L.; Moretto, Ph. [Université Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France)

    2013-07-01

    High resolution ion microbeams, usually used to perform elemental mapping, low dose targeted irradiation or ion beam lithography needs a very flexible beam control system. For this purpose, we have developed a dedicated system (called “CRionScan”), on the AIFIRA facility (Applications Interdisciplinaires des Faisceaux d’Ions en Région Aquitaine). It consists of a stand-alone real-time scanning and imaging instrument based on a Compact Reconfigurable Input/Output (Compact RIO) device from National Instruments™. It is based on a real-time controller, a Field Programmable Gate Array (FPGA), input/output modules and Ethernet connectivity. We have implemented a fast and deterministic beam scanning system interfaced with our commercial data acquisition system without any hardware development. CRionScan is built under LabVIEW™ and has been used on AIFIRA’s nanobeam line since 2009 (Barberet et al., 2009, 2011) [1,2]. A Graphical User Interface (GUI) embedded in the Compact RIO as a web page is used to control the scanning parameters. In addition, a fast electrostatic beam blanking trigger has been included in the FPGA and high speed counters (15 MHz) have been implemented to perform dose controlled irradiation and on-line images on the GUI. Analog to Digital converters are used for the beam current measurement and in the near future for secondary electrons imaging. Other functionalities have been integrated in this controller like LED lighting using Pulse Width Modulation and a “NIM Wilkinson ADC” data acquisition.

  14. Stand-alone photovoltaic (PV) integrated with earth to air heat exchanger (EAHE) for space heating/cooling of adobe house in New Delhi (India)

    International Nuclear Information System (INIS)

    Chel, Arvind; Tiwari, G.N.

    2010-01-01

    This paper deals with an experimental outdoor annual performance evaluation of 2.32 kW P photovoltaic (PV) power system located at solar energy park in New Delhi composite climatic conditions. This PV system operates the daily electrical load nearly 10 kW h/day which comprises of various applications such as electric air blower of an earth to air heat exchanger (EAHE) used for heating/cooling of adobe house, ceiling fan, fluorescent tube-light, computer, submersible water pump, etc. The outdoor efficiencies, power generated and lost in PV system components were determined using hourly experimental measured data for 1 year on typical clear day in each month. These realistic data are useful for design engineers for outdoor assessment of PV system components. The energy conservation, mitigation of CO 2 emission and carbon credit potential of the existing PV integrated EAHE system is presented in this paper. Also, the energy payback time (EPBT) and unit cost of electricity were determined for both stand-alone PV (SAPV) and building roof integrated PV (BIPV) systems.

  15. Direct Flux Control for Stand-Alone Operation Brushless Doubly Fed Induction Generators Using a Resonant-Based Sliding-Mode Control Approach

    Directory of Open Access Journals (Sweden)

    Kai Ji

    2018-04-01

    Full Text Available In this paper, a novel voltage control strategy for stand-alone operation brushless doubly fed induction generators for variable speed constant frequency wind energy conversion systems was presented and discussed. Based on the model of the power generation system, the proposed direct flux control strategy employs a nonlinear reduced-order generalized integrator-based resonant sliding-mode control approach to directly calculate and regulate the output value of converter which the control winding stator requires so as to eliminate its instantaneous errors, without involving any synchronous rotating coordinate transformations. The stability, robustness and convergence capability of the proposed control strategy were described and analyzed. Owing to the fact no additional current control inner loops are involved, the system configuration is therefore simplified and the dynamic performance enhanced. A constant converter switching frequency was achieved by using space vector pulse width modulation, which reduces the harmonics of the generator terminal voltage. In addition, the feasibility and validity of the proposed scheme is verified by experiments, and excellent steady and transient performance is achieved.

  16. Anterior interbody fusion for cervical osteomyelitis

    Science.gov (United States)

    Bartal, A. D.; Schiffer, J.; Heilbronn, Y. D.; Yahel, M.

    1972-01-01

    Interbody fusion for stabilization of the cervical spine after osteomyelitic destruction of the body of C5 vertebra is reported in a patient with quadriplegia and sphincter disturbances secondary to an epidural abscess. The successful union of the bone graft along with complete neurological recovery after anterior decompression and evacuation of the epidural mass seem to justify the procedure. Images PMID:4554587

  17. The international phase 4 validation study of the EORTC QLQ-SWB32: A stand-alone measure of spiritual well-being for people receiving palliative care for cancer

    NARCIS (Netherlands)

    Vivat, B.; Young, T. E.; Winstanley, J.; Arraras, J. I.; Black, K.; Boyle, F.; Bredart, A.; Costantini, A.; Guo, J.; Irarrazaval, M. E.; Kobayashi, K.; Kruizinga, R.; Navarro, M.; Omidvari, S.; Rohde, G. E.; Serpentini, S.; Spry, N.; van Laarhoven, H. W. M.; Yang, G. M.

    2017-01-01

    The EORTC Quality of Life Group has just completed the final phase (field-testing and validation) of an international project to develop a stand-alone measure of spiritual well-being (SWB) for palliative cancer patients. Participants (n = 451)-from 14 countries on four continents; 54% female; 188

  18. The Impact of Course Delivery Systems on Student Achievement and Sense of Community: A Comparison of Learning Community versus Stand-Alone Classroom Settings in an Open-Enrollment Inner City Public Community College

    Science.gov (United States)

    Bandyopadhyay, Pamela

    2010-01-01

    This study examined the effects of two types of course delivery systems (learning community classroom environments versus stand-alone classroom environments) on the achievement of students who were simultaneously enrolled in remedial and college-level social science courses at an inner city open-enrollment public community college. This study was…

  19. CANGS DB: a stand-alone web-based database tool for processing, managing and analyzing 454 data in biodiversity studies

    Directory of Open Access Journals (Sweden)

    Schlötterer Christian

    2011-06-01

    Full Text Available Abstract Background Next generation sequencing (NGS is widely used in metagenomic and transcriptomic analyses in biodiversity. The ease of data generation provided by NGS platforms has allowed researchers to perform these analyses on their particular study systems. In particular the 454 platform has become the preferred choice for PCR amplicon based biodiversity surveys because it generates the longest sequence reads. Nevertheless, the handling and organization of massive amounts of sequencing data poses a major problem for the research community, particularly when multiple researchers are involved in data acquisition and analysis. An integrated and user-friendly tool, which performs quality control, read trimming, PCR primer removal, and data organization is desperately needed, therefore, to make data interpretation fast and manageable. Findings We developed CANGS DB (Cleaning and Analyzing Next Generation Sequences DataBase a flexible, stand alone and user-friendly integrated database tool. CANGS DB is specifically designed to organize and manage the massive amount of sequencing data arising from various NGS projects. CANGS DB also provides an intuitive user interface for sequence trimming and quality control, taxonomy analysis and rarefaction analysis. Our database tool can be easily adapted to handle multiple sequencing projects in parallel with different sample information, amplicon sizes, primer sequences, and quality thresholds, which makes this software especially useful for non-bioinformaticians. Furthermore, CANGS DB is especially suited for projects where multiple users need to access the data. CANGS DB is available at http://code.google.com/p/cangsdb/. Conclusion CANGS DB provides a simple and user-friendly solution to process, store and analyze 454 sequencing data. Being a local database that is accessible through a user-friendly interface, CANGS DB provides the perfect tool for collaborative amplicon based biodiversity surveys

  20. Hydrogen-based energy storage unit for stand alone PV systems; L'hydrogene electrolytique comme moyen de stockage d'electricite pour systemes photovoltaiques isoles

    Energy Technology Data Exchange (ETDEWEB)

    Labbe, J

    2006-12-15

    Stand alone systems supplied only by a photovoltaic generator need an energy storage unit to be fully self sufficient. Lead acid batteries are commonly used to store energy because of their low cost, despite several operational constraints. A hydrogen-based energy storage unit (HESU) could be another candidate, including an electrolyser, a fuel cell and a hydrogen tank. However many efforts still need to be carried out for this technology to reach an industrial stage. In particular, market outlets must be clearly identified. The study of small stationary applications (few kW) is performed by numerical simulations. A simulator is developed in the Matlab/Simulink environment. It is mainly composed of a photovoltaic field and a storage unit (lead acid batteries, HESU, or hybrid storage HESU/batteries). The system component sizing is achieved in order to ensure the complete system autonomy over a whole year of operation. The simulator is tested with 160 load profiles (1 kW as a yearly mean value) and three locations (Algeria, France and Norway). Two coefficients are set in order to quantify the correlation between the power consumption of the end user and the renewable resource availability at both daily and yearly scales. Among the tested cases, a limit value of the yearly correlation coefficient came out, enabling to recommend the use of the most adapted storage to a considered case. There are cases for which using HESU instead of lead acid batteries can increase the system efficiency, decrease the size of the photovoltaic field and improve the exploitation of the renewable resource. In addition, hybridization of HESU with batteries always leads to system enhancements regarding its sizing and performance, with an efficiency increase by 10 to 40 % depending on the considered location. The good agreement between the simulation data and field data gathered on real systems enabled the validation of the models used in this study. (author)

  1. Further development of LLNA:DAE method as stand-alone skin-sensitization testing method and applied for evaluation of relative skin-sensitizing potency between chemicals.

    Science.gov (United States)

    Yamashita, Kunihiko; Shinoda, Shinsuke; Hagiwara, Saori; Itagaki, Hiroshi

    2015-04-01

    To date, there has been no well-established local lymph node assay (LLNA) that includes an elicitation phase. Therefore, we developed a modified local lymph node assay with an elicitation phase (LLNA:DAE) to discriminate true skin sensitizers from chemicals that gave borderline positive results and previously reported this assay. To develop the LLNA:DAE method as a useful stand-alone testing method, we investigated the complete procedure for the LLNA:DAE method using hexyl cinnamic aldehyde (HCA), isoeugenol, and 2,4-dinitrochlorobenzene (DNCB) as test compounds. We defined the LLNA:DAE procedure as follows: in the dose-finding test, four concentrations of chemical applied to dorsum of the right ear on days 1, 2, and 3 and dorsum of both ears on day 10. Ear thickness and skin irritation score were measured on days 1, 3, 5, 10, and 12. Local lymph nodes were excised and weighed on day 12. The test dose for the primary LLNA:DAE study was selected as the dose that gave the highest left ear lymph node weight in the dose-finding study, or the lowest dose that produced a left ear lymph node of over 4 mg. This procedure was validated using nine different chemicals. Furthermore, qualitative relationship was observed between the degree of elicitation response in the left ear lymph node and the skin sensitizing potency of 32 chemicals tested in this study and the previous study. These results indicated that LLNA:DAE method was as first LLNA method that was able to evaluate the skin sensitizing potential and potency in elicitation response.

  2. Effects of a stand-alone web-based electronic screening and brief intervention targeting alcohol use in university students of legal drinking age: A randomized controlled trial.

    Science.gov (United States)

    Ganz, Thomas; Braun, Michael; Laging, Marion; Schermelleh-Engel, Karin; Michalak, Johannes; Heidenreich, Thomas

    2018-02-01

    Many intervention efforts targeting student drinking were developed to address US college students, which usually involves underage drinking. It remains unclear, if research evidence from these interventions is generalizable to university and college students of legal drinking age, e.g., in Europe. To evaluate the effectiveness of a translated and adapted version of the eCHECKUP TO GO, applied as stand-alone web-based electronic screening and brief intervention (e-SBI), in German university students at risk for hazardous drinking. A fully automated web-based two-arm parallel-group randomized controlled trial was conducted. Participants were randomized to an e-SBI or assessment-only (AO) condition. The current paper analyzed students with baseline AUDIT-C scores ≥3 for women and ≥4 for men (sample at baseline: e-SBI [n=514], AO [n=467]; 3-month follow-up: e-SBI [n=194], AO [n=231]; 6-month follow-up: e-SBI [n=146], AO [n=200]). The primary outcome was prior four weeks' alcohol consumption. Secondary outcomes were frequency of heavy drinking occasions, peak blood alcohol concentration, and number of alcohol-related problems. Mixed linear model analyses revealed significant interaction effects between groups and time points on the primary outcome after 3 and 6months. Compared to students in the AO condition, students in the e-SBI condition reported consuming 4.11 fewer standard drinks during the previous four weeks after 3months, and 4.78 fewer standard drinks after 6months. Mixed results were found on secondary outcomes. The results indicate that evidence on and knowledge of web-based e-SBIs based on US college student samples is transferable to German university students of legal drinking age. However, knowledge of what motivates students to complete programs under voluntary conditions, although rare, is needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test.

    Science.gov (United States)

    Gonfiotti, Bruno; Paci, Sandro

    2018-03-01

    During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA) in a Nuclear Power Plant (NPP). Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR) fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV) have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP) behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel.

  4. Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test

    Directory of Open Access Journals (Sweden)

    Bruno Gonfiotti

    2018-03-01

    Full Text Available During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA in a Nuclear Power Plant (NPP. Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel. Keywords: Safety

  5. Complications in posterior lumbar interbody fusion

    OpenAIRE

    Kreuzer, Rolf-Peter

    2010-01-01

    From 1993 to 2000, 220 consecutive patients with unstable degenerative spondylolisthesis were studied after posterior lumbar interbody fusion (PLIF) using different types of grafts and pedicle screw systems. In a retrospective review the author detail the associated complications and their correlation with perioperative factors. The causes, strategies for their avoidance, and the clinical course of these complications are also disscused. The study group was composed of 136 women and 84 men...

  6. [Mechanical studies of lumbar interbody fusion implants].

    Science.gov (United States)

    Bader, R J; Steinhauser, E; Rechl, H; Mittelmeier, W; Bertagnoli, R; Gradinger, R

    2002-05-01

    In addition to autogenous or allogeneic bone grafts, fusion cages composed of metal or plastic are being used increasingly as spacers for interbody fusion of spinal segments. The goal of this study was the mechanical testing of carbon fiber reinforced plastic (CFRP) fusion cages used for anterior lumbar interbody fusion. With a special testing device according to American Society for Testing and Materials (ASTM) standards, the mechanical properties of the implants were determined under four different loading conditions. The implants (UNION cages, Medtronic Sofamor Danek) provide sufficient axial compression, shear, and torsional strength of the implant body. Ultimate axial compression load of the fins is less than the physiological compression loads at the lumbar spine. Therefore by means of an appropriate surgical technique parallel grooves have to be reamed into the endplates of the vertebral bodies according to the fin geometry. Thereby axial compression forces affect the implants body and the fins are protected from damaging loading. Using a supplementary anterior or posterior instrumentation, in vivo failure of the fins as a result of physiological shear and torsional spinal loads is unlikely. Due to specific complications related to autogenous or allogeneic bone grafts, fusion cages made of metal or carbon fiber reinforced plastic are an important alternative implant in interbody fusion.

  7. Mini-open transforaminal lumbar interbody fusion.

    Science.gov (United States)

    Tangviriyapaiboon, Teera

    2008-09-01

    To demonstrate the surgical technique and advantages of the mini-open transforaminal approach for lumbar interbody fusion (TLIF) combined with transpedicular screw fixation. Clinical and radiographic results were assessed to determine the clinical outcomes in twelve consecutive patients selected for minimally invasive access (mini-open technique) for TLIF in Prasat Neurological Institute. A retrospective analysis was performed on 12 patients (age range, 38-74 yr; mean, 54. 8 yr) who underwent mini-open transforaminal approach for lumbar interbody fusion (TLIF) combined with transpedicular screw fixation between September 2006 and June 2008. The titanium pedicle screws were introduced bilaterally through the 3.5 cm length, skin incisions with Spine Classics MLD- system retractor, autologous bone graft were inserted to perform TLIF in all patients. Eight patients were augmented anterior column support with titanium interbody cage, unilateral cage insertion in four patients and the others were inserted bilaterally interbody cages. Six patients presented with low back pain and associated radiculopathy, and six presented with low back pain only. Transforaminal lumbar interbody fusion was performed at L3-L4 in two patients, L4-L5 in four patients, L5-S1 in five patients, and two levels fusion in one patient. All patients were able to ambulate after spinal fusion. The patients were able to walk within 1.4 days (range 1-2 days). The hospital stay averaged 4.4 days (range 3-7 days). Periodic follow-up took place 1 to 21 months after surgery (mean, 7.4 months). The radiological fusion was archived in all nine patients who were operated on more than two months age. The other three patients who had been follow-up less than two months were probably fusion on the 1-month followed-up radiological examination. The use of mini-open technique for pedicle screw instrumentation with spinal fusion procedure provides excellent clinical results and may be an operation of choice for

  8. Wireless network of stand-alone end effect probes for soil in situ permittivity measurements over the 100MHZ-6GHz frequency range

    Science.gov (United States)

    Demontoux, François; Bircher, Simone; Ruffié, Gilles; Bonnaudiin, Fabrice; Wigneron, Jean-Pierre; Kerr, Yann

    2017-04-01

    , it should be useful to install many probes on the same site to obtain permittivity measurements over a large area. To reach this goal, the probes should communicate with each other to send data to a record device. Furthermore, it is needed to record measurements over a long time period (many months) to study the in-situ dielectric soil property variations according to changing weather conditions and seasonal trends. The goal of the research work presented is to develop a dielectric sensor system based on end effect probes able to communicate the data using wireless technology. It must be stand-alone from an electric and data recording point of view so it must integrate a VNA circuit instead of the ANRITSU VNA used for the moment. The LoRa wireless technology has been selected because of its low electric consumption and the large distance between equipment available. LoRaWAN™ is a Low Power Wide Area Network specification intended for wireless battery operated devices. The LoRaWAN data rates range from 0.3 kbps to 50 kbps which is sufficient for our probes' data exchanges. We will present the work done to perform the VNA and the LoRa communication board as well as the work done to improve the probes and the permittivity computation algorithm.

  9. Tricortical cervical inter-body screw fixation.

    Directory of Open Access Journals (Sweden)

    Goel A

    1997-01-01

    Full Text Available A new tricortical method of screw implantation for anterior cervical interbody plate fixation is described. The screws are placed obliquely such that they engage the anterior cortex of the body and traverse through the cortices adjoining the disc space. By this method the screws not only hold the plate firmly with a tricortical purchase, but by virtue of their course stabilize the two adjoining vertebral bodies by themselves. Sixteen patients were treated by this method. In three of these cases only tricortical screws without the metal plate were used for fixation. The advantages of the technique are discussed.

  10. IEA PVPS Task 3. Use of photovoltaic systems in stand-alone and island applications. 'Swiss participation'; IEA PVPS Task 3. Use of photovoltaic systems in stand-alone and island applications. 'Participation Suisse'

    Energy Technology Data Exchange (ETDEWEB)

    Villoz, M. [Dynatex SA, Morges (Switzerland)

    2004-07-01

    This report describes the work done during five years of the second phase of Task 3 of the photovoltaic power systems programme of the International Energy Agency (IEA-PVPS). Task 3 activities were concentrated on stand-alone photovoltaic systems with the main effort on improving the quality and reducing the cost of these systems. The work was divided in 2 sub-tasks whose first one was concentrated on quality insurance schemes and second one on technical recommendations coming from practical experience. Twelve original reports have been published covering topics that can be sorted in 4 categories: the first one is dedicated on quality issues with a review of existing standards in the participating countries and a double paper giving quality assurance recommendations on project management and examples of applying these rules in practical cases. The second category dwelled on photovoltaic systems with papers on charge controllers, on lightning protection and monitoring of systems. The third category presents interesting studies on the storage of energy which remains the main subject where improvements should be made in order to lower the cost of energy; four papers describe the management and the test procedures of lead-acid batteries, how to choose a lead-acid battery and finally are there alternatives to lead-acid batteries for the storage of photovoltaic electricity. The last category worked on loads and users of renewable energy and gives a large amount of experience with loads, how to choose them and how the energy can be better used through demand side management. (author)

  11. Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy and Improved Combined Cooling-Heating-Power Strategy Based Two-Time Scale Multi-Objective Optimization Model for Stand-Alone Microgrid Operation

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-11-01

    Full Text Available The optimal dispatching model for a stand-alone microgrid (MG is of great importance to its operation reliability and economy. This paper aims at addressing the difficulties in improving the operational economy and maintaining the power balance under uncertain load demand and renewable generation, which could be even worse in such abnormal conditions as storms or abnormally low or high temperatures. A new two-time scale multi-objective optimization model, including day-ahead cursory scheduling and real-time scheduling for finer adjustments, is proposed to optimize the operational cost, load shedding compensation and environmental benefit of stand-alone MG through controllable load (CL and multi-distributed generations (DGs. The main novelty of the proposed model is that the synergetic response of CL and energy storage system (ESS in real-time scheduling offset the operation uncertainty quickly. And the improved dispatch strategy for combined cooling-heating-power (CCHP enhanced the system economy while the comfort is guaranteed. An improved algorithm, Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy (SIP-CO-PSO-ERS algorithm with strong searching capability and fast convergence speed, was presented to deal with the problem brought by the increased errors between actual renewable generation and load and prior predictions. Four typical scenarios are designed according to the combinations of day types (work day or weekend and weather categories (sunny or rainy to verify the performance of the presented dispatch strategy. The simulation results show that the proposed two-time scale model and SIP-CO-PSO-ERS algorithm exhibit better performance in adaptability, convergence speed and search ability than conventional methods for the stand-alone MG’s operation.

  12. The international phase 4 validation study of the EORTC QLQ-SWB32: a stand-alone measure of spiritual wellbeing (SWB) for people receiving palliative care for cancer

    OpenAIRE

    Vivat, B.; Young, T.; Winstanley, J.; Arraras, J.; Black, K.; Boyle, F.; Brédart, A.; Costantini, A.; Guo, J.; Irarrazaval, M. E.; Kobayashi, K.; Kruizinga, R.; Navarro, M.; Omidvari, S.; Rohde, G. E.

    2017-01-01

    The EORTC Quality of Life (QL) Group has just completed the final phase (field-testing and validation) of an international project to develop a stand-alone measure of spiritual wellbeing (SWB) for palliative cancer patients. Participants (n= 451) - from 14 countries on four continents; 54% female; 188 Christian, 50 Muslim, 156 with no religion - completed a provisional 36-item measure of SWB plus the EORTC QLQ-C15-PAL (PAL), then took part in a structured debriefing interview. All items showe...

  13. Single or double-level anterior interbody fusion techniques for cervical degenerative disc disease

    NARCIS (Netherlands)

    Jacobs, Wilco; Willems, Paul C.; van Limbeek, Jacques; Bartels, Ronald; Pavlov, Paul; Anderson, Patricia G.; Oner, Cumhur

    2011-01-01

    Background The number of surgical techniques for decompression and solid interbody fusion as treatment for cervical spondylosis has increased rapidly, but the rationale for the choice between different techniques remains unclear. Objectives To determine which technique of anterior interbody fusion

  14. Feasibility Analysis and Simulation of a Stand-Alone Photovoltaic Energy System for Electricity Generation and Environmental Sustainability – Equivalent to 650VA Fuel-Powered Generator – Popularly Known as “I Pass My Neighbour”

    International Nuclear Information System (INIS)

    Ani, Vincent Anayochukwu

    2015-01-01

    Photovoltaic (PV) power system can be used to replace wholly 650VA generator for electricity generation for household use in Nigeria. This paper presented the feasibility analysis of load data and simulation study of a stand-alone PV power system that produced the electrical needs of a household. This study is based on designing of PV energy system for household use. The patterns of load consumption within the household were studied and suitably modeled for simulation. The simulation study indicates that energy requirements to provide electricity, which is equivalent to 650VA generator for household use in Nigeria, can be accomplished by 520 W solar PV array, 2312 Ah nominal capacity battery, and a 1 kW DC/AC inverter. This would be suitable for deployment of 100% clean energy for environmental sustainability and uninterruptable power performance in the household. The results of this research show that, with a low-power consuming appliances, it is possible to meet the entire annual electricity demand of a single household solely through a stand-alone PV energy supply. Installing solar panels by most Nigerian home can significantly reduce home reliance on government power thereby reduce the strain on the current capacity of our power generation infrastructure. A detailed design and description of the system were presented in this paper.

  15. Feasibility Analysis and Simulation of a Stand-Alone Photovoltaic Energy System for Electricity Generation and Environmental Sustainability – Equivalent to 650VA Fuel-Powered Generator – Popularly Known as “I Pass My Neighbour”

    Energy Technology Data Exchange (ETDEWEB)

    Ani, Vincent Anayochukwu, E-mail: vincent_ani@yahoo.com [Department of Electronic Engineering, University of Nigeria Nsukka, Nsukka (Nigeria)

    2015-09-11

    Photovoltaic (PV) power system can be used to replace wholly 650VA generator for electricity generation for household use in Nigeria. This paper presented the feasibility analysis of load data and simulation study of a stand-alone PV power system that produced the electrical needs of a household. This study is based on designing of PV energy system for household use. The patterns of load consumption within the household were studied and suitably modeled for simulation. The simulation study indicates that energy requirements to provide electricity, which is equivalent to 650VA generator for household use in Nigeria, can be accomplished by 520 W solar PV array, 2312 Ah nominal capacity battery, and a 1 kW DC/AC inverter. This would be suitable for deployment of 100% clean energy for environmental sustainability and uninterruptable power performance in the household. The results of this research show that, with a low-power consuming appliances, it is possible to meet the entire annual electricity demand of a single household solely through a stand-alone PV energy supply. Installing solar panels by most Nigerian home can significantly reduce home reliance on government power thereby reduce the strain on the current capacity of our power generation infrastructure. A detailed design and description of the system were presented in this paper.

  16. [Axial lumbar interbody fusion: prospective monocentric study].

    Science.gov (United States)

    Stulík, J; Adámek, S; Barna, M; Kaspříková, N; Polanecký, O; Kryl, J

    2014-01-01

    The aim of this prospective study was to evaluate clinical and radiographic results in the patients who underwent L5-S1 fixation using the technique of percutaneous lumbar interbody fusion (AxiaLIF). The study comprised 23 patients, 11 women and 12 men, who ranged from age of 21 to 63 years, with an average of 48.2 years. In all patients surgical posterior stabilisation involving the L5-S1 segment had previously been done. The initial indications for surgery were L5-S1 spondylolisthesis in 20 and L5-S1 spondylosis and stenosis in three patients. The AxiaLIF technique for L5-S1 fixation was indicated in overweight patients and in those after repeated abdominal or retroperitoneal surgery. A suitable position and shape of the sacrum or lumbosacral junction was another criterion. The patients were evaluated between 26 and 56 months (average, 40.4 months) after primary surgery and, on the basis of CT and radiographic findings, bone union and lumbosacral junction stability were assessed. The clinical outcome was investigated using the ODI and VAS systems and the results were statistically analysed by the Wilcoxon test for paired samples with statistical significance set at a level of 0.05. The average VAS value was 6.6 before surgery and, after surgery, 5.2 at three months, 4.2 at six months, 3.1 at one year, 2.9 at two years and 2.1 at three years (n=18). At two post-operative years, improvement in the VAS value by 56.1% was recorded. The average pre-operative ODI value was 25.1; the post-operative values were 17.0 at six months, 12.3 at one year, 10.6 at two years and 8.2 at three years (n=18). At two years after surgery the ODI value improved by 57.8%. To the question concerning their willingness to undergo, with acquired experience, surgery for the same diagnosis, 21 patients (91.3%) gave an affirmative answer. Neither screw breakage nor neurovascular damage or rectal injury was found. CT scans showed complete interbody bone fusion in 22 of the 23 patients (95

  17. Is the radiographic subsidence of stand-alone cages associated with adverse clinical outcomes after cervical spine fusion? An observational cohort study with 2-year follow-up outcome scoring.

    Science.gov (United States)

    Zajonz, Dirk; Franke, Anne-Catherine; von der Höh, Nicolas; Voelker, Anna; Moche, Michael; Gulow, Jens; Heyde, Christoph-Eckhard

    2014-01-01

    The stand-alone treatment of degenerative cervical spine pathologies is a proven method in clinical practice. However, its impact on subsidence, the resulting changes to the profile of the cervical spine and the possible influence of clinical results compared to treatment with additive plate osteosynthesis remain under discussion until present. This study was designed as a retrospective observational cohort study to test the hypothesis that radiographic subsidence of cervical cages is not associated with adverse clinical outcomes. 33 cervical segments were treated surgically by ACDF with stand-alone cage in 17 patients (11 female, 6 male), mean age 56 years (33-82 years), and re-examined after eight and twenty-six months (mean) by means of radiology and score assessment (Medical Outcomes Study Short Form (MOS-SF 36), Oswestry Neck Disability Index (ONDI), painDETECT questionnaire and the visual analogue scale (VAS)). Subsidence was observed in 50.5% of segments (18/33) and 70.6% of patients (12/17). 36.3% of cases of subsidence (12/33) were observed after eight months during mean time of follow-up 1. After 26 months during mean time of follow-up 2, full radiographic fusion was seen in 100%. MOS-SF 36, ONDI and VAS did not show any significant difference between cases with and without subsidence in the two-sample t-test. Only in one type of scoring (painDETECT questionnaire) did a statistically significant difference in t-Test emerge between the two groups (p = 0.03; α = 0.05). However, preoperative painDETECT score differ significantly between patients with subsidence (13.3 falling to 12.6) and patients without subsidence (7.8 dropped to 6.3). The radiological findings indicated 100% healing after stand-alone treatment with ACDF. Subsidence occurred in 50% of the segments treated. No impact on the clinical results was detected in the medium-term study period.

  18. CHANGES IN RADIOGRAPHIC PARAMETERS AFTER MINIMALLY INVASIVE LUMBAR INTERBODY FUSION

    Directory of Open Access Journals (Sweden)

    Emiliano Vialle

    2015-12-01

    Full Text Available Objective : This study aims to evaluate changes in lumbosacral parameters after minimally invasive lumbar interbody fusion. The secondary aim was to evaluate whether interbody cage shape (crescent shaped or rectangular would influence the results. Method : Retrospective analysis of 70 patients who underwent one or two level lumbar interbody fusion through a minimally invasive posterolateral approach. This included midline preservation and unilateral facetectomy. Pre- and postoperative (three to six months postoperative radiographs were used for measuring lumbar lordosis (LL, segmental lordosis (SL at the level of interbody fusion, and sacral slope (SS. Further analyses divided the patients into Roussouly lumbar subgroups. Results : LL was significantly reduced after surgery (59o:39o, p=0.001 as well as the SS (33.8o:31.2o, p=0.05. SL did not change significantly (11.4:11.06, p=0.85. There were no significant differences when comparing patients who received crescent shaped cage (n=27 and rectangular cage (n=43. Hypolordotic patients (Roussouly types 1 and 2 had radiographic improvement in comparison to normolordotic and hyperlordotic groups (types 3 and 4. Conclusion : Minimally invasive lumbar interbody fusion caused reduction in lumbosacral parameters. Cage shape had no influence on the results.

  19. Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion--systematic review and meta-analysis.

    Science.gov (United States)

    Phan, Kevin; Thayaparan, Ganesha K; Mobbs, Ralph J

    2015-01-01

    To assess the clinical and radiographic outcomes and complications of anterior lumbar interbody fusion (ALIF) versus transforaminal lumbar interbody fusion (TLIF). A systematic literature search was conducted from six electronic databases. The relative risk and weighted mean difference (WMD) were used as statistical summary effect sizes. Fusion rates (88.6% vs. 91.9%, P = 0.23) and clinical outcomes were comparable between ALIF and TLIF. ALIF was associated with restoration of disk height (WMD, 2.71 mm, P = 0.01), segmental lordosis (WMD, 2.35, P = 0.03), and whole lumbar lordosis (WMD, 6.33, P = 0.03). ALIF was also associated with longer hospitalization (WMD, 1.8 days, P = 0.01), lower dural injury (0.4% vs. 3.8%, P = 0.05) but higher blood vessel injury (2.6% vs. 0%, P = 0.04). ALIF and TLIF appear to have similar success and clinical outcomes, with different complication profiles. ALIF may be associated with superior restoration of disk height and lordosis, but requires further validation in future studies.

  20. Comparison of interbody fusion approaches for disabling low back pain.

    Science.gov (United States)

    Hacker, R J

    1997-03-15

    This is a study comparing two groups of patients surgically treated for disabling low back pain. One group was treated with lumbar anteroposterior fusion (360 degrees fusion), the other with posterior lumbar interbody fusion and an interbody fixation device. To determine which approach provided the best and most cost-effective outcome using similar patient selection criteria. Others have shown that certain patients with disabling low back pain benefit from lumbar fusion. Although rarely reported, the costs of different surgical treatments appear to vary significantly, whereas the patient outcome may vary little. Since 1991, 75 patients have been treated Starting in 1993, posterior lumbar interbody fusion BAK was offered to patients as an alternative to 360 degrees fusion. The treating surgeon reviewed the cases. The interbody fixation device used (BAK; Spine-Tech, Inc., Minneapolis, MN) was part of a Food and Drug Administration study. Patient selection criteria included examination, response to conservative therapy, imaging, psychological profile, and discography. North American Spine Society outcome questionnaires, BAK investigation data radiographs, chart entries, billing records and patient interviews were the basis for assessment. Age, sex compensable injury history and history of previous surgery were similar. Operative time; blood loss, hospitalization time, and total costs were significantly different. There was a quicker return to work and closure of workers compensation claims for the posterior lumbar interbody fusion-BAK group. Patient satisfaction was comparable at last follow-up. Posterior lumbar interbody fusion-BAK achieves equal patient satisfaction but fiscally surpasses the 360 degrees fusion approach. Today's environment of regulated medical practice requires the surgeon to consider cost effectiveness when performing fusion for low back pain.

  1. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; Palma, Atilio E; Martinez-Del-Campo, Eduardo; Crawford, Neil R; Theodore, Nicholas; Kelly, Brian P; Kaibara, Taro

    2018-06-01

    Recently developed expandable interbody spacers are widely accepted in spinal surgery; however, the resulting biomechanical effects of their use have not yet been fully studied. We analyzed the biomechanical effects of an expandable polyetheretherketone interbody spacer inserted through a bilateral posterior approach with and without different modalities of posterior augmentation. Biomechanical nondestructive flexibility testing was performed in 7 human cadaveric lumbar (L2-L5) specimens followed by axial compressive loading. Each specimen was tested under 6 conditions: 1) intact, 2) bilateral L3-L4 cortical screw/rod (CSR) alone, 3) WaveD alone, 4) WaveD + CSR, 5) WaveD + bilateral L3-L4 pedicle screw/rod (PSR), and 6) WaveD + CSR/PSR, where CSR/PSR was a hybrid construct comprising bilateral cortical-level L3 and pedicle-level L4 screws interconnected by rods. The range of motion (ROM) with the interbody spacer alone decreased significantly compared with the intact condition during flexion-extension (P = 0.02) but not during lateral bending or axial rotation (P ≥ 0.19). The addition of CSR or PSR to the interbody spacer alone condition significantly decreased the ROM compared with the interbody spacer alone (P ≤ 0.002); and WaveD + CSR, WaveD + PSR, and WaveD + CSR/PSR (hybrid) (P ≥ 0.29) did not differ. The axial compressive stiffness (resistance to change in foraminal height during compressive loading) with the interbody spacer alone did not differ from the intact condition (P = 0.96), whereas WaveD + posterior instrumentation significantly increased compressive stiffness compared with the intact condition and the interbody spacer alone (P ≤ 0.001). The WaveD alone significantly reduced ROM during flexion-extension while maintaining the axial compressive stiffness. CSR, PSR, and CSR/PSR hybrid constructs were all effective in augmenting the expandable interbody spacer system and improving its stability. Copyright © 2018 Elsevier Inc. All

  2. Stand alone biofuel production from algae

    NARCIS (Netherlands)

    Wijffels, R.H.; Janssen, M.G.J.; Barbosa, M.J.

    2011-01-01

    In this feature, leading researchers in the field of microbial biotechnology speculate on the technical and conceptual developments that will drive innovative research and open new vistas over the next few years

  3. Informing Approaches in Establishing Stand Alone Community ...

    African Journals Online (AJOL)

    Literacy is usually considered the ability to read at a basic level. Now it is beginning to be defined more broadly to include applying reading, writing, and mathematical skills to obtain and use information and solve problems at levels of proficiency necessary to function in society, to achieve one's goals and develop one's ...

  4. Stand Alone Battery Thermal Management System

    Energy Technology Data Exchange (ETDEWEB)

    Brodie, Brad [Denso International America, Incorporated, Southfield, MI (United States)

    2015-09-30

    The objective of this project is research, development and demonstration of innovative thermal management concepts that reduce the cell or battery weight, complexity (component count) and/or cost by at least 20%. The project addresses two issues that are common problems with current state of the art lithium ion battery packs used in vehicles; low power at cold temperatures and reduced battery life when exposed to high temperatures. Typically, battery packs are “oversized” to satisfy the two issues mentioned above. The first phase of the project was spent making a battery pack simulation model using AMEsim software. The battery pack used as a benchmark was from the Fiat 500EV. FCA and NREL provided vehicle data and cell data that allowed an accurate model to be created that matched the electrical and thermal characteristics of the actual battery pack. The second phase involved using the battery model from the first phase and evaluate different thermal management concepts. In the end, a gas injection heat pump system was chosen as the dedicated thermal system to both heat and cool the battery pack. Based on the simulation model. The heat pump system could use 50% less energy to heat the battery pack in -20°C ambient conditions, and by keeping the battery cooler at hot climates, the battery pack size could be reduced by 5% and still meet the warranty requirements. During the final phase, the actual battery pack and heat pump system were installed in a test bench at DENSO to validate the simulation results. Also during this phase, the system was moved to NREL where testing was also done to validate the results. In conclusion, the heat pump system can improve “fuel economy” (for electric vehicle) by 12% average in cold climates. Also, the battery pack size, or capacity, could be reduced 5%, or if pack size is kept constant, the pack life could be increased by two years. Finally, the total battery pack and thermal system cost could be reduced 5% only if the system is integrated with the vehicle cabin air conditioning system. The reason why we were not able to achieve the 20% reduction target is because of the natural decay of the battery cell due to the number of cycles. Perhaps newer battery chemistries that are not so sensitive to cycling would have more potential for reducing the battery size due to thermal issues.

  5. Chapter 2: Stand-alone Applications - TOPCAT

    Science.gov (United States)

    Miller, C. J.

    Tool for OPerations on Catalogues And Tables or TOPCAT is a graphical viewer for table data. It offers a variety of ways to work with data tables, including a browser for the cell data, viewers for information about table and column metadata, dataset visualization, and even analysis. We discuss a small subset of TOPCAT's functionalities in this chapter. TOPCAT was originally developed as part of the Starlink program in the United Kingdom. It is now maintained by AstroGrid. The program is written in pure Java and available under the GNU General Public License. It is available for download and a version is included in the software distribution accompanying this book. TOPCAT is a GUI interface on top of the STIL library. A command line interface to this library, STILTS, described in Chapter 21 provides scriptable access to many of the capabilities described here. The purpose of this tutorial is to provide an overview of TOPCAT to the novice user. The best place to look for and learn about TOPCAT is the web page maintained by Mark B. Taylor. There, TOPCAT documentation is provided in HTML, PDF, via screen shots, etc. In this chapter we take the user through a few examples that give the general idea of how TOPCAT works. The majority of the functionality of TOPCAT is not included in this short tutorial. Our goal in this tutorial is to lead the reader through an exercise that would result in a publication quality figure (e.g. for a journal article). Specifically, we will use TOPCAT to show how the color-magnitude relation of a galaxy cluster compares to that of all galaxies in the Sloan Digital Sky Survey (York et al. 2000). This diagnostic is used not only in cluster finding, but its linear fit can provide insight into the age and/or metallicity of the oldest galaxies in galaxy clusters (which are some of the oldest galaxies in the Universe). The data we need for this exercise are: 1) the entire spectroscopic galaxy catalog from the SDSS, with galaxy positions, galaxy redshifts, and galaxy magnitudes and 2) galaxy members of a known galaxy cluster. For the former, we will download data directly from the SDSS servers to our local machine for analysis. For the latter, we will use TOPCAT's ability to call live cone search services.

  6. ANALYSIS OF INTERBODY VERSUS POSTEROLATERAL FUSION FOR LUMBAR SPONDYLOSIS

    Directory of Open Access Journals (Sweden)

    Rodrigo Góes Medéa de Mendonça

    2015-12-01

    Full Text Available Objective : To evaluate and compare radiographic and clinical evaluation of patients undergoing interbody fusion versus posterolateral fusion of the lumbar spine. Methods : Retrospective study of patients diagnosed with lumbar spondylosis that were surgically treated in the period from 2012 to 2014. The results were observed by clinical evaluation by the Visual Analogue Scale (VAS for low back and leg pain. We evaluated functional results and quality of life through the application of the Oswestry Disability Index (ODI and the Short Form-36 (SF-36 questionnaires, respectively. The pre and postoperative condition were compared in Group 1 (interbody fusion and Group 2 (posterolateral fusion, in addition to evaluation of fusion by means of post-operative radiograph. Results : A total of 30 patients of 36 were eligible, 12 in Group 1 and 18 in Group 2. The mean follow-up was 10.1 months. Statistical analysis showed similar scores for back and leg pain VAS, SF-36 function scores and Oswestry between groups with interbody and posterolateral fusion, and compared within these groups regarding the pre- and postoperative condition, and found no statistical significance. The successful fusion was similar in both groups, with 11 of 12 patients in Group 1 showing bone fusion and 17 of 18 in Group 2 showing arthrodesis. Conclusion : No clinical or radiographic differences between patients who underwent posterolateral or interbody fusion were observed. Both methods showed improvement in functional outcome and pain reduction.

  7. [Anterior lumbar interbody fusion. Indications, technique, advantages and disadvantages].

    Science.gov (United States)

    Richter, M; Weidenfeld, M; Uckmann, F P

    2015-02-01

    Anterior lumbar interbody fusion (ALIF) for lumbar interbody fusion from L2 to the sacrum has been an established technique for decades. The advantages and disadvantages of ALIF compared to posterior interbody fusion techniques are discussed. The operative technique is described in detail. Complications and avoidance strategies are discussed. This article is based on a selective literature search using PubMed and the experience of the authors in this medical field. The advantages of ALIF compared to posterior fusion techniques are the free approach to the anterior disc space without opening of the spinal canal or the neural foramina. This gives the possibility of an extensive anterior release and placement of the largest possible cages without the risk of neural structure damage. The disadvantages of ALIF are the additional anterior approach and the related complications. The most frequent complication is due to damage of vessels. The rate of complications is significantly increased in revision surgery. The ALIF technique meaningfully expands the repertoire of the spinal surgeon especially for the treatment of non-union after interbody fusion, in patients with epidural scar tissue at the index level and spinal infections. Advantages and disadvantages should be considered when evaluating the indications for ALIF.

  8. Lumbar interbody fusion: techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF

    Science.gov (United States)

    Phan, Kevin; Malham, Greg; Seex, Kevin; Rao, Prashanth J.

    2015-01-01

    Degenerative disc and facet joint disease of the lumbar spine is common in the ageing population, and is one of the most frequent causes of disability. Lumbar spondylosis may result in mechanical back pain, radicular and claudicant symptoms, reduced mobility and poor quality of life. Surgical interbody fusion of degenerative levels is an effective treatment option to stabilize the painful motion segment, and may provide indirect decompression of the neural elements, restore lordosis and correct deformity. The surgical options for interbody fusion of the lumbar spine include: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), minimally invasive transforaminal lumbar interbody fusion (MI-TLIF), oblique lumbar interbody fusion/anterior to psoas (OLIF/ATP), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF). The indications may include: discogenic/facetogenic low back pain, neurogenic claudication, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity including symptomatic spondylolisthesis and degenerative scoliosis. In general, traditional posterior approaches are frequently used with acceptable fusion rates and low complication rates, however they are limited by thecal sac and nerve root retraction, along with iatrogenic injury to the paraspinal musculature and disruption of the posterior tension band. Minimally invasive (MIS) posterior approaches have evolved in an attempt to reduce approach related complications. Anterior approaches avoid the spinal canal, cauda equina and nerve roots, however have issues with approach related abdominal and vascular complications. In addition, lateral and OLIF techniques have potential risks to the lumbar plexus and psoas muscle. The present study aims firstly to comprehensively review the available literature and evidence for different lumbar interbody fusion (LIF) techniques. Secondly, we propose a set of recommendations and guidelines

  9. Multi-site evaluation of a computer aided detection (CAD) algorithm for small acute intra-cranial hemorrhage and development of a stand-alone CAD system ready for deployment in a clinical environment

    Science.gov (United States)

    Deshpande, Ruchi R.; Fernandez, James; Lee, Joon K.; Chan, Tao; Liu, Brent J.; Huang, H. K.

    2010-03-01

    Timely detection of Acute Intra-cranial Hemorrhage (AIH) in an emergency environment is essential for the triage of patients suffering from Traumatic Brain Injury. Moreover, the small size of lesions and lack of experience on the reader's part could lead to difficulties in the detection of AIH. A CT based CAD algorithm for the detection of AIH has been developed in order to improve upon the current standard of identification and treatment of AIH. A retrospective analysis of the algorithm has already been carried out with 135 AIH CT studies with 135 matched normal head CT studies from the Los Angeles County General Hospital/ University of Southern California Hospital System (LAC/USC). In the next step, AIH studies have been collected from Walter Reed Army Medical Center, and are currently being processed using the AIH CAD system as part of implementing a multi-site assessment and evaluation of the performance of the algorithm. The sensitivity and specificity numbers from the Walter Reed study will be compared with the numbers from the LAC/USC study to determine if there are differences in the presentation and detection due to the difference in the nature of trauma between the two sites. Simultaneously, a stand-alone system with a user friendly GUI has been developed to facilitate implementation in a clinical setting.

  10. The international phase 4 validation study of the EORTC QLQ-SWB32: A stand-alone measure of spiritual well-being for people receiving palliative care for cancer.

    Science.gov (United States)

    Vivat, B; Young, T E; Winstanley, J; Arraras, J I; Black, K; Boyle, F; Bredart, A; Costantini, A; Guo, J; Irarrazaval, M E; Kobayashi, K; Kruizinga, R; Navarro, M; Omidvari, S; Rohde, G E; Serpentini, S; Spry, N; Van Laarhoven, H W M; Yang, G M

    2017-11-01

    The EORTC Quality of Life Group has just completed the final phase (field-testing and validation) of an international project to develop a stand-alone measure of spiritual well-being (SWB) for palliative cancer patients. Participants (n = 451)-from 14 countries on four continents; 54% female; 188 Christian; 50 Muslim; 156 with no religion-completed a provisional 36-item measure of SWB plus the EORTC QLQ-C15-PAL (PAL), then took part in a structured debriefing interview. All items showed good score distribution across response categories. We assessed scale structure using principal component analysis and Rasch analysis, and explored construct validity, and convergent/divergent validity with the PAL. Twenty-two items in four scoring scales (Relationship with Self, Relationships with Others, Relationship with Someone or Something Greater, and Existential) explained 53% of the variance. The measure also includes a global SWB item and nine other items. Scores on the PAL global quality-of-life item and Emotional Functioning scale weakly-moderately correlated with scores on the global SWB item and two of the four SWB scales. This new validated 32-item SWB measure addresses a distinct aspect of quality-of-life, and is now available for use in research and clinical practice, with a role as both a measurement and an intervention tool. © 2017 John Wiley & Sons Ltd.

  11. Guarded Cubical Type Theory

    DEFF Research Database (Denmark)

    Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald

    2016-01-01

    This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning...... with coinductive types. We wish to implement GDTT with decidable type-checking, while still supporting non-trivial equality proofs that reason about the extensions of guarded recursive constructions. CTT is a variation of Martin-L\\"of type theory in which the identity type is replaced by abstract paths between...... terms. CTT provides a computational interpretation of functional extensionality, is conjectured to have decidable type checking, and has an implemented type-checker. Our new type theory, called guarded cubical type theory, provides a computational interpretation of extensionality for guarded recursive...

  12. Guarded Cubical Type Theory

    DEFF Research Database (Denmark)

    Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald

    2016-01-01

    This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning...... with coinductive types. We wish to implement GDTT with decidable type checking, while still supporting non-trivial equality proofs that reason about the extensions of guarded recursive constructions. CTT is a variation of Martin-L\\"of type theory in which the identity type is replaced by abstract paths between...... terms. CTT provides a computational interpretation of functional extensionality, enjoys canonicity for the natural numbers type, and is conjectured to support decidable type-checking. Our new type theory, guarded cubical type theory (GCTT), provides a computational interpretation of extensionality...

  13. Post-processing in cardiovascular computed tomography. Performance of a client server solution versus a stand-alone solution; Bildnachverarbeitung in der kardiovaskulaeren Computertomografie. Performance von Client-Server- versus Einzelplatzloesung

    Energy Technology Data Exchange (ETDEWEB)

    Luecke, C.; Foldyna, B.; Andres, C.; Grothoff, M.; Nitzsche, S.; Gutberlet, M.; Lehmkuhl, L. [Leipzig Univ. - Herzzentrum (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie; Boehmer-Lasthaus, S. [Siemens Healthcare Sector, Erlangen (Germany). Imaging and Therapy Div.

    2014-12-15

    Purpose: To compare the performance of server-based (CSS) versus stand-alone post-processing software (ES) for the evaluation of cardiovascular CT examinations (cvCT) and to determine the crucial steps. Data of 40 patients (20 patients for coronary artery evaluation and 20 patients prior to transcatheter aortic valve implantation [TAVI]) were evaluated by 5 radiologists with CSS and ES. Data acquisition was performed using a dual-source 128-row CT unit (SOMATOM Definition Flash, Siemens, Erlangen, Germany) and a 64-row CT unit (Brilliance 64, Philips, Hamburg, Germany). The following workflow was evaluated: Data loading, aorta and coronary segmentation, curved multiplanar reconstruction (cMPR) and 3 D volume rendering technique (3D-VRT), measuring of coronary artery stenosis and planimetry of the aortic annulus. The time requirement and subjective quality for the workflow were evaluated. The coronary arteries as well as the TAVI data could be evaluated significantly faster with CSS (5.5 ± 2.9 min and 8.2 ± 4.0 min, respectively) than with ES (13.9 ± 5.2 min and 15.2 ± 10.9 min, respectively, p = 0.01). Segmentation of the aorta (CSS: 1.9 ± 2.0 min, ES: 3.7 ± 3.3 min), generating cMPR of coronaries (CSS: 0.5 ± 0.2 min, ES: 5.1 ± 2.6 min), aorta and iliac vessels (CSS: 0.5 ± 0.4 min and 0.4 ± 0.4 min, respectively, ES: 1.6 ± 0.7 min and 2.8 ± 3 min, respectively) could be performed significantly faster with CSS than with ES with higher quality of cMPR, measuring of coronary stenosis and 3D-VRT (p < 0.05). Evaluation of cvCT can be accomplished significantly faster and better with CSS than with ES. The segmentation remains the most time-consuming workflow step, so optimization of segmentation algorithms could improve performance even further.

  14. STAND-ALONE WIND ENERGY CONVERSION SYSTEM WITH MAXIMUM POWER TRANSFER CONTROL SISTEMA AISLADO DE CONVERSIÓN EÓLICA CON CONTROL DE MÁXIMA TRANSFERENCIA DE POTENCIA

    Directory of Open Access Journals (Sweden)

    Miguel López

    2009-12-01

    Full Text Available A controlled wind generation system for a stand alone application is presented in this paper. A cascaded step-up/step-down power electronic converters topology is proposed to control the wind power system in the whole wind speed range. For the low wind speed range, the control strategy is aimed to follow the wind turbine’s maximal power coefficient by adjusting the generator’s rotational speed. For high wind speeds, the system power regulation is also made by controlling the generator speed. This control is made by the DC/DC power electronic converter, which modifies its input voltage, changing the machine voltage and consequently varying the generator’s rotor speed. The proposed system is validated by computer simulation. The proposed control system shows a good performance for its application in autonomous wind energy systems.Un sistema de generación eólica para una aplicación aislada es presentado en este artículo. Una topología de convertidores electrónicos de potencia elevador y reductor conectados en cascada es propuesta para controlar la producción eólica en todo el rango de velocidades del viento. Para el rango de vientos suaves, la estrategia de control permite seguir el máximo coeficiente de potencia de turbina eólica mediante el ajuste de la velocidad de rotación del generador. En el rango de vientos fuertes, la regulación de la potencia del sistema se hace igualmente por control de la velocidad de giro del generador. La acción de control es realizada mediante el convertidor DC/DC de potencia el cual modifica su tensión de entrada, cambiando así la tensión en los terminales de la máquina y por consecuencia variando la velocidad de rotación del generador. El sistema propuesto es validado mediante simulación por computador. Los resultados muestran que el sistema de control propuesto actúa de buena manera para su aplicación en sistemas autónomos de generación eólica.

  15. Interpolation of natural cubic spline

    Directory of Open Access Journals (Sweden)

    Arun Kumar

    1992-01-01

    Full Text Available From the result in [1] it follows that there is a unique quadratic spline which bounds the same area as that of the function. The matching of the area for the cubic spline does not follow from the corresponding result proved in [2]. We obtain cubic splines which preserve the area of the function.

  16. The expandable transforaminal lumbar interbody fusion – Two years follow-up

    Directory of Open Access Journals (Sweden)

    Joseph Gamal Boktor

    2018-01-01

    Conclusions: These preliminary results indicate that the use of an expandable interbody cage achieves good clinical outcomes by improving and maintaining foraminal dimensions and disc height with minimal complication rate.

  17. Anterior lumbar fusion with titanium threaded and mesh interbody cages.

    Science.gov (United States)

    Rauzzino, M J; Shaffrey, C I; Nockels, R P; Wiggins, G C; Rock, J; Wagner, J

    1999-12-15

    The authors report their experience with 42 patients in whom anterior lumbar fusion was performed using titanium cages as a versatile adjunct to treat a wide variety of spinal deformity and pathological conditions. These conditions included congenital, degenerative, iatrogenic, infectious, traumatic, and malignant disorders of the thoracolumbar spine. Fusion rates and complications are compared with data previously reported in the literature. Between July 1996 and July 1999 the senior authors (C.I.S., R.P.N., and M.J.R.) treated 42 patients by means of a transabdominal extraperitoneal (13 cases) or an anterolateral extraperitoneal approach (29 cases), 51 vertebral levels were fused using titanium cages packed with autologous bone. All vertebrectomies (27 cases) were reconstructed using a Miami Moss titanium mesh cage and Kaneda instrumentation. Interbody fusion (15 cases) was performed with either the BAK titanium threaded interbody cage (in 13 patients) or a Miami Moss titanium mesh cage (in two patients). The average follow-up period was 14.3 months. Seventeen patients had sustained a thoracolumbar burst fracture, 12 patients presented with degenerative spinal disorders, six with metastatic tumor, four with spinal deformity (one congenital and three iatrogenic), and three patients presented with spinal infections. In five patients anterior lumbar interbody fusion (ALIF) was supplemented with posterior segmental fixation at the time of the initial procedure. Of the 51 vertebral levels treated, solid arthrodesis was achieved in 49, a 96% fusion rate. One case of pseudarthrosis occurred in the group treated with BAK cages; the diagnosis was made based on the patient's continued mechanical back pain after undergoing L4-5 ALIF. The patient was treated with supplemental posterior fixation, and successful fusion occurred uneventfully with resolution of her back pain. In the group in which vertebrectomy was performed there was one case of fusion failure in a patient with

  18. Analysis of Internet Information on Lateral Lumbar Interbody Fusion.

    Science.gov (United States)

    Belayneh, Rebekah; Mesfin, Addisu

    2016-07-01

    Lateral lumbar interbody fusion (LLIF) is a surgical technique that is being increasingly used. The authors' objective was to examine information on the Internet pertaining to the LLIF technique. An analysis was conducted of publicly accessible websites pertaining to LLIF. The following search engines were used: Google (www.google.com), Bing (www.bing.com), and Yahoo (www.yahoo.com). DuckDuckGo (www.duckduckgo.com) was an additional search engine used due to its emphasis on generating accurate and consistent results while protecting searchers' privacy and reducing advertisements. The top 35 websites providing information on LLIF from the 4 search engines were identified. A total of 140 websites were evaluated. Each web-site was categorized based on authorship (academic, private, medical industry, insurance company, other) and content of information. Using the search term lateral lumbar interbody fusion, 174,000 Google results, 112,000 Yahoo results, and 112,000 Bing results were obtained. DuckDuckGo does not display the number of results found for a search. From the top 140 websites collected from each website, 78 unique websites were identified. Websites were authored by a private medical group in 46.2% of the cases, an academic medical group in 26.9% of the cases, and the biomedical industry in 5.1% of the cases. Sixty-eight percent of websites reported indications, and 24.4% reported contraindications. Benefits of LLIF were reported by 69.2% of websites. Thirty-six percent of websites reported complications of LLIF. Overall, the quality of information regarding LLIF on the Internet is poor. Spine surgeons and spine societies can assist in improving the quality of the information on the Internet regarding LLIF. [Orthopedics. 2016; 39(4):e701-e707.]. Copyright 2016, SLACK Incorporated.

  19. A comparison of anterior cervical discectomy and fusion (ACDF) using self-locking stand-alone polyetheretherketone (PEEK) cage with ACDF using cage and plate in the treatment of three-level cervical degenerative spondylopathy: a retrospective study with 2-year follow-up.

    Science.gov (United States)

    Chen, Yuqiao; Lü, Guohua; Wang, Bing; Li, Lei; Kuang, Lei

    2016-07-01

    To evaluate the clinical efficacy and radiological outcomes of anterior cervical discectomy and fusion (ACDF) using self-locking polyetheretherketone (PEEK) cages for treatment of three-level cervical degenerative spondylopathy. Twenty-eight patients underwent three-level ACDF using self-locking stand-alone PEEK cages (group A), and 26 patients underwent three-level ACDF using cages and plate fixation (group B) were reviewed retrospectively. Clinical efficacy was evaluated by pre- and post-operative Japanese Orthopedic Association (JOA) scores and Neck Disability Index (NDI). The operation time, blood loss, surgical results according to Odom's criteria and post-operative dysphagia status were also recorded. Radiological outcomes including fusion, cervical Cobb's lordosis, fused segment angle, disc height, and cage subsidence were assessed. Clinical outcome measures such as dysphagia and fusion rate and the results of surgery evaluated according to Odom's criteria were not statistically significant (P > 0.05) between groups. The operation time was shorter and blood loss was less in group A (P  0.05). Post-operative cage subsidence, the loss of disc height, cervical lordosis and the fused segment angle were relatively higher in group A than group B (P < 0.05). ACDF using self-locking stand-alone cages showed similar clinical results as compared to ACDF using cages and plate fixation for the treatment of three-level cervical degenerative spondylopathy. However, potential long-term problems such as cage subsidence, loss of cervical lordosis and fused segment angle post-operatively were shown to be associated with patients who underwent ACDF using self-locking stand-alone cages.

  20. Fiscal 2000 regional new energy vision formulation - Financially aided project. Report on regional new energy vision formulation for Ueno village (Object of survey: Commercialization feasibility study for a stand-alone type wind power generation system at Ueno German Culture Village); 2000 nendo Uenoson chiiki shin energy vision sakutei hokokusho. Ueno Doitsu bunkamura dokuritsugata furyoku hatsuden system jigyoka feasibility study chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-02-01

    A survey is conducted about the profitability of installing a stand-alone type wind power system at Ueno village (Miyako Island), Okinawa Prefecture. The German Culture Village, which is an integrated resort house provided with accommodations (500 people), educational and cultural facilities, and sports facilities consumes 272 MWh/year in electric power. The results of the survey are summarized in six chapters, which are (1) the survey of the business under the project to be the object of feasibility study, (2) project to be the object of feasibility study, (3) outline of the Okinawa Electric Power Co., Inc., Miyakojima system and problems to ensue from its interconnection with wind turbines, (4) survey of stand-alone type wind turbine power generation systems, (5) technical/economic feasibility study, and (6) project management and future tasks. It is concluded that there will be profit in the presence of a subsidy that covers 65% or more of the total cost of constructing a system comprising three 600 KW wind turbines, three 400 kW class diesel generators, and storage batteries. (NEDO)

  1. Evaluation of a polyetheretherketone (PEEK) titanium composite interbody spacer in an ovine lumbar interbody fusion model: biomechanical, microcomputed tomographic, and histologic analyses.

    Science.gov (United States)

    McGilvray, Kirk C; Waldorff, Erik I; Easley, Jeremiah; Seim, Howard B; Zhang, Nianli; Linovitz, Raymond J; Ryaby, James T; Puttlitz, Christian M

    2017-12-01

    The most commonly used materials used for interbody cages are titanium metal and polymer polyetheretherketone (PEEK). Both of these materials have demonstrated good biocompatibility. A major disadvantage associated with solid titanium cages is their radiopacity, limiting the postoperative monitoring of spinal fusion via standard imaging modalities. However, PEEK is radiolucent, allowing for a temporal assessment of the fusion mass by clinicians. On the other hand, PEEK is hydrophobic, which can limit bony ingrowth. Although both PEEK and titanium have demonstrated clinical success in obtaining a solid spinal fusion, innovations are being developed to improve fusion rates and to create stronger constructs using hybrid additive manufacturing approaches by incorporating both materials into a single interbody device. The purpose of this study was to examine the interbody fusion characteristic of a PEEK Titanium Composite (PTC) cage for use in lumbar fusion. Thirty-four mature female sheep underwent two-level (L 2 -L 3 and L 4 -L 5 ) interbody fusion using either a PEEK or a PTC cage (one of each per animal). Animals were sacrificed at 0, 8, 12, and 18 weeks post surgery. Post sacrifice, each surgically treated functional spinal unit underwent non-destructive kinematic testing, microcomputed tomography scanning, and histomorphometric analyses. Relative to the standard PEEK cages, the PTC constructs demonstrated significant reductions in ranges of motion and a significant increase in stiffness. These biomechanical findings were reinforced by the presence of significantly more bone at the fusion site as well as ingrowth into the porous end plates. Overall, the results indicate that PTC interbody devices could potentially lead to a more robust intervertebral fusion relative to a standard PEEK device in a clinical setting. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. The planar cubic Cayley graphs

    CERN Document Server

    Georgakopoulos, Agelos

    2018-01-01

    The author obtains a complete description of the planar cubic Cayley graphs, providing an explicit presentation and embedding for each of them. This turns out to be a rich class, comprising several infinite families. He obtains counterexamples to conjectures of Mohar, Bonnington and Watkins. The author's analysis makes the involved graphs accessible to computation, corroborating a conjecture of Droms.

  3. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    Science.gov (United States)

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  4. An Abel type cubic system

    Directory of Open Access Journals (Sweden)

    Gary R. Nicklason

    2015-07-01

    Full Text Available We consider center conditions for plane polynomial systems of Abel type consisting of a linear center perturbed by the sum of 2 homogeneous polynomials of degrees n and 2n-1 where $n \\ge 2$. Using properties of Abel equations we obtain two general systems valid for arbitrary values on n. For the cubic n=2 systems we find several sets of new center conditions, some of which show that the results in a paper by Hill, Lloyd and Pearson which were conjectured to be complete are in fact not complete. We also present a particular system which appears to be a counterexample to a conjecture by Zoladek et al. regarding rational reversibility in cubic polynomial systems.

  5. Cubication of conservative nonlinear oscillators

    International Nuclear Information System (INIS)

    Belendez, Augusto; Alvarez, Mariela L; Fernandez, Elena; Pascual, Inmaculada

    2009-01-01

    A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear and cubic terms depend on the initial amplitude, A, while in a Taylor expansion of the restoring force these coefficients are independent of A. The replacement of the original nonlinear equation by an approximate Duffing equation allows us to obtain an approximate frequency-amplitude relation as a function of the complete elliptic integral of the first kind. Some conservative nonlinear oscillators are analysed to illustrate the usefulness and effectiveness of this scheme.

  6. Numbers for reducible cubic scrolls

    Directory of Open Access Journals (Sweden)

    Israel Vainsencher

    2004-12-01

    Full Text Available We show how to compute the number of reducible cubic scrolls of codimension 2 in (math blackboard symbol Pn incident to the appropriate number of linear spaces.Mostramos como calcular o número de rolos cúbicos redutíveis de codimensão 2 em (math blackboard symbol Pn incidentes a espaços lineares apropriados.

  7. Randomized Block Cubic Newton Method

    KAUST Repository

    Doikov, Nikita; Richtarik, Peter

    2018-01-01

    We study the problem of minimizing the sum of three convex functions: a differentiable, twice-differentiable and a non-smooth term in a high dimensional setting. To this effect we propose and analyze a randomized block cubic Newton (RBCN) method, which in each iteration builds a model of the objective function formed as the sum of the natural models of its three components: a linear model with a quadratic regularizer for the differentiable term, a quadratic model with a cubic regularizer for the twice differentiable term, and perfect (proximal) model for the nonsmooth term. Our method in each iteration minimizes the model over a random subset of blocks of the search variable. RBCN is the first algorithm with these properties, generalizing several existing methods, matching the best known bounds in all special cases. We establish ${\\cal O}(1/\\epsilon)$, ${\\cal O}(1/\\sqrt{\\epsilon})$ and ${\\cal O}(\\log (1/\\epsilon))$ rates under different assumptions on the component functions. Lastly, we show numerically that our method outperforms the state-of-the-art on a variety of machine learning problems, including cubically regularized least-squares, logistic regression with constraints, and Poisson regression.

  8. Randomized Block Cubic Newton Method

    KAUST Repository

    Doikov, Nikita

    2018-02-12

    We study the problem of minimizing the sum of three convex functions: a differentiable, twice-differentiable and a non-smooth term in a high dimensional setting. To this effect we propose and analyze a randomized block cubic Newton (RBCN) method, which in each iteration builds a model of the objective function formed as the sum of the natural models of its three components: a linear model with a quadratic regularizer for the differentiable term, a quadratic model with a cubic regularizer for the twice differentiable term, and perfect (proximal) model for the nonsmooth term. Our method in each iteration minimizes the model over a random subset of blocks of the search variable. RBCN is the first algorithm with these properties, generalizing several existing methods, matching the best known bounds in all special cases. We establish ${\\\\cal O}(1/\\\\epsilon)$, ${\\\\cal O}(1/\\\\sqrt{\\\\epsilon})$ and ${\\\\cal O}(\\\\log (1/\\\\epsilon))$ rates under different assumptions on the component functions. Lastly, we show numerically that our method outperforms the state-of-the-art on a variety of machine learning problems, including cubically regularized least-squares, logistic regression with constraints, and Poisson regression.

  9. Alternative route of process modification for biofuel production by embedding the Fischer-Tropsch plant in existing stand-alone power plant (10 MW) based on biomass gasification - Part I: A conceptual modeling and simulation approach (a case study in Thailand)

    DEFF Research Database (Denmark)

    Hunpinyo, Piyapong; Cheali, Peam; Narataruksa, Phavanee

    2014-01-01

    a base case process model coupled with techno-economic evaluation for the FT synthesis. In particular, the FT process configurations are designed and assessed using current kinetic laboratory data by our research group for modeling specific reactions in PFR reactor. The calculation of equipment sizing......The utilization of syngas shows a highly potential to improve the economic potential of the stand-alone power unit-based gasification plants as well as enhancing the growing demand of transportation fuels. The thermochemical conversion of biomass via gasification to heat and power generations from...... incurred several major unit operations is performed for once-through mode (no recycles of unconverted syngas) with electricity co-production. This study provides a detailed base-case model for the synthesis with the capacities of 1, 2 and 3 MW of syngas technology sharing and the comparison between...

  10. Study of a stand alone power system based on a photovoltaic field, an electrolyser and a fuel cell: test bench and modelling; Etude d'un systeme autonome de production d'energie couplant un champ photovoltaique, un electrolyseur et une pile a combustible: realisation d'un banc d'essai et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Busquet, S.

    2003-12-01

    Our energetic future has to be based on non-polluting energies with long-term resources. Renewable energies are the best candidates but as their production is intermittent, storage way is necessary as well efficient as environmentally friendly. Coupled an electrolyser and a fuel cell allows to store electricity in gas form and furthermore to produce heat energy. The goal of this work is to evaluate performances of a stand-alone power system, producing electricity and heat, coupling a photovoltaic field and a hydrogen storage system, made of an electrolyser, a gas storage unit and a fuel cell. Hydrogen is the unique way to store electricity. To complete this task, two tools have been developed: a 3,6 kW test bench and a simulation tool. To select the test bench, a bibliographic study enables to collect the necessary information to size and to choice the system and its components. The low availability of components adapted to our application, forces us to create new devices (electrolyser, fuel cell, power management unit). The test bench is automatic and safe. Experimental analysis evaluates the efficiency of the hydrogen storage system, determining the different losses occurring in each component. Modifications are proposed to increase the performances of the storage system. The simulation tool enables to plan the operating of the test bench for a fixed load and place. This model can simulate any system based on experimental data of each component. Simulation results enable to characterise the functioning of the test bench in a stand-alone operation, to determine its performances and to evaluate the influence of the different losses. (author)

  11. Cubic colloids : Synthesis, functionalization and applications

    NARCIS (Netherlands)

    Castillo, S.I.R.

    2015-01-01

    This thesis is a study on cubic colloids: micron-sized cubic particles with rounded corners (cubic superballs). Owing to their shape, particle packing for cubes is more efficient than for spheres and results in fascinating phase and packing behavior. For our cubes, the particle volume fraction when

  12. Outcomes of extended transforaminal lumbar interbody fusion for lumbar spondylosis.

    Science.gov (United States)

    Talia, Adrian J; Wong, Michael L; Lau, Hui C; Kaye, Andrew H

    2015-11-01

    This study aims to assess the results of extended transforaminal lumbar interbody fusion (TLIF) for a two surgeon, single institution series. In total, extended TLIF with bilateral decompression was performed in 57 patients. Pain, American Spinal Injury Association scores, patient demographics, body mass index (BMI), perioperative indices and radiographic measurements were recorded and analysed. The surgeries were performed between February 2011 and January 2014 on 38 women and 19 men. The mean patient age was 62.86 years, and the mean BMI was 30.31 kg/m(2). In 49 patients, spondylolisthesis was the primary indication. The mean intraoperative time was 284.65 min, and this decreased as the series progressed. The median length of stay was 5 days (range: 2-9). The surgical complication rate was 19.3%. Two patients died from cardiopulmonary complications. Single level TLIF was performed in 78.9% of the cohort, with L4/5 the most commonly fused level. Significant pain reduction was achieved from a mean (± standard deviation) preoperative visual analogue scale (VAS) of 8.28 ± 1.39 to 1.50 ± 1.05 at 12 months postoperatively. No patients deteriorated neurologically. Spondylolisthesis was significantly corrected from a preoperative mean of 6.82 mm to 2.80 mm postoperatively. Although there is a learning curve associated with the procedure, extended TLIF with bilateral facet joint removal and decompression appeared to be a safe and effective alternative to other fusion techniques, and our results were comparable to other published case series. The stabilisation and correction of spinal deformity reduces pain, aids neurologic recovery and improves quality of life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Two-year outcomes of transforaminal lumbar interbody fusion.

    Science.gov (United States)

    Poh, Seng Yew; Yue, Wai Mun; Chen, Li-Tat John; Guo, Chang-Ming; Yeo, William; Tan, Seang-Beng

    2011-08-01

    To evaluate the outcomes, fusion rates, complications, and adjacent segment degeneration associated with transforaminal lumbar interbody fusion (TLIF). 32 men and 80 women aged 15 to 85 (mean, 57) years underwent 141 fusions (84 one-level, 27 2-level, and one 3-level) and were followed up for 24 to 76 (mean, 33) months. 92% of the patients had degenerative lumbar disease, 15 of whom had had previous lumbar surgery. Radiographic and clinical outcomes were assessed at 2 years. The short-form 36 (SF-36) health survey, visual analogue scale (VAS) for pain, and the modified North American Spine Society (NASS) Low Back Pain Outcome Instrument were used. Of the 141 levels fused, 110 (78%) were fused with remodelling and trabeculae (grade I), and 31 (22%) had intact grafts but were not fully incorporated (grade II). No patient had pseudoarthroses (grade III or IV). For one-level fusions, poorer radiological fusion grades correlated with higher VAS scores for pain (p<0.01). All components of the SF-36, the VAS scores for pain, and the NASS scores improved significantly after TLIF (p<0.01), except for general health in the SF-36 (p=0.59). Improvement from postoperative 6 months to 2 years was not significant, except for physical function (p<0.01) and role function (physical) [p=0.01] in the SF-36. Two years after TLIF, 50% of the patients reported returning to full function, whereas 72% were satisfied. 26 (23%) of the patients had adjacent segment degeneration, but only 4 of them were symptomatic. TLIF is a safe and effective treatment for degenerative lumbar diseases.

  14. Evaluation of Anterior Vertebral Interbody Fusion Using Osteogenic Mesenchymal Stem Cells Transplanted in Collagen Sponge.

    Science.gov (United States)

    Yang, Wencheng; Dong, Youhai; Hong, Yang; Guang, Qian; Chen, Xujun

    2016-05-01

    The study used a rabbit model to achieve anterior vertebral interbody fusion using osteogenic mesenchymal stem cells (OMSCs) transplanted in collagen sponge. We investigated the effectiveness of graft material for anterior vertebral interbody fusion using a rabbit model by examining the OMSCs transplanted in collagen sponge. Anterior vertebral interbody fusion is commonly performed. Although autogenous bone graft remains the gold-standard fusion material, it requires a separate surgical procedure and is associated with significant short-term and long-term morbidity. Recently, mesenchymal stem cells from bone marrow have been studied in various fields, including posterolateral spinal fusion. Thus, we hypothesized that cultured OMSCs transplanted in porous collagen sponge could be used successfully even in anterior vertebral interbody fusion. Forty mature male White Zealand rabbits (weight, 3.5-4.5 kg) were randomly allocated to receive one of the following graft materials: porous collagen sponge plus cultured OMSCs (group I); porous collagen sponge alone (group II); autogenous bone graft (group III); and nothing (group IV). All animals underwent anterior vertebral interbody fusion at the L4/L5 level. The lumbar spine was harvested en bloc, and the new bone formation and spinal fusion was evaluated using radiographic analysis, microcomputed tomography, manual palpation test, and histologic examination at 8 and 12 weeks after surgery. New bone formation and bony fusion was evident as early as 8 weeks in groups I and III. And there was no statistically significant difference between 8 and 12 weeks. At both time points, by microcomputed tomography and histologic analysis, new bone formation was observed in both groups I and III, fibrous tissue was observed and there was no new bone in both groups II and IV; by manual palpation test, bony fusion was observed in 40% (4/10) of rabbits in group I, 70% (7/10) of rabbits in group III, and 0% (0/10) of rabbits in both groups

  15. Cubic metaplectic forms and theta functions

    CERN Document Server

    Proskurin, Nikolai

    1998-01-01

    The book is an introduction to the theory of cubic metaplectic forms on the 3-dimensional hyperbolic space and the author's research on cubic metaplectic forms on special linear and symplectic groups of rank 2. The topics include: Kubota and Bass-Milnor-Serre homomorphisms, cubic metaplectic Eisenstein series, cubic theta functions, Whittaker functions. A special method is developed and applied to find Fourier coefficients of the Eisenstein series and cubic theta functions. The book is intended for readers, with beginning graduate-level background, interested in further research in the theory of metaplectic forms and in possible applications.

  16. Cathodoluminescence of cubic boron nitride

    International Nuclear Information System (INIS)

    Tkachev, V.D.; Shipilo, V.B.; Zajtsev, A.M.

    1985-01-01

    Three optically active defects are detected in mono- and polycrystal cubic boron nitride (β-BN). Analysis of intensity of temperature dependences, halfwidth and energy shift of 1.76 eV narrow phononless line (center GC-1) makes it possible to interprete the observed cathodoluminescence spectra an optical analog of the Moessbaner effect. Comparison of the obtained results with the known data for diamond monocrystals makes it possible to suggest that the detected center GC-1 is a nitrogen vacancy . The conclusion, concerning the Moessbauer optical spectra application, is made to analyze structural perfection of β-BN crystal lattice

  17. Clinical study of bilateral decompression via vertebral lamina fenestration for lumbar interbody fusion in the treatment of lower lumbar instability

    OpenAIRE

    GUO, SHUGUANG; SUN, JUNYING; TANG, GENLIN

    2013-01-01

    The aim of this study was to observe the clinical effects of bilateral decompression via vertebral lamina fenestration for lumbar interbody fusion in the treatment of lower lumbar instability. The 48 patients comprised 27 males and 21 females, aged 47?72 years. Three cases had first and second degree lumbar spondylolisthesis and all received bilateral vertebral lamina fenestration for posterior lumbar interbody fusion (PLIF) using a threaded fusion cage (TFC), which maintains the three-column...

  18. Performance evaluation of stand alone hybrid PV-wind generator

    International Nuclear Information System (INIS)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-01-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand

  19. Radon Monitoring in Army Stand-Alone Housing Units

    Science.gov (United States)

    1990-04-01

    damage lung tissue and lead I to increased risk of developing lang cancer . Your risk of developing lung cancer from exposure to radon depends upon the...of developing lung cancer than exposure to a significantly elevated level for a short time. In general, your risk increases as the level of radon and...000mm 0Mmm *000 OOO 0 0w 0 0 000 -0-0 *4 0 880 mama 0 0000000000 000 000Eca ( el cN) 00 9 ’ qqO .00 1(10 0 -U M w co SEE wSS SEES NSEwESO m v MM O v mm

  20. Performance evaluation of stand alone hybrid PV-wind generator

    Science.gov (United States)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  1. Algal Hydrogen Production -- Stand Alone or Integrated System?

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, Maria L.; Maness, Pin Ching; Kosourovo, Sergey

    2016-01-01

    Photosynthetic bacteria and green algae photoproduce H2. but do so utilizing different catalysts and substrates. Green algae use reductant generate mostly by water oxidation to catalyze the reduction of protons to H2 gas, while photosynthetic bacteria catalyze H2 production from organic acids using the nitrogenase enzyme. Moreover, these two organisms utilize different regions of the solar spectrum to perform photosynthesis: green algae's light harvesting antenna is comprised of chlorophyll molecules that absorb mostly blue and red light; photosynthetic bacteria harvest blue and far-red light through their light-harvesting pigments to run its non-oxygenic photosynthetic reactions. There is thus an opportunity to increase the range of solar spectrum used to photoproduce H2 by combining the light-harvesting and catalytic properties of these two organisms in a single process. In the current manuscript, we describe an experimental system that validates this hypothesis and demonstrates quantitatively the advantages of a two organism process for production of higher amounts of H2 and thus achieving solar light conversion efficiencies.

  2. Deterrents on the Over Utilisation of Stand Alone Photovoltaic (PV ...

    African Journals Online (AJOL)

    At inception of the programme, systems were either undersized, or over utilised as clients did not reveal their usage needs in an attempt to reduce costs. This resulted in battery failures and other system breakdowns. The NPVREP categorised systems in order to alleviate the problem of under sizing and/or over utilization of ...

  3. Basic Stand Alone Medicare Claims Public Use Files

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS is committed to increasing access to its Medicare claims data through the release of de-identified data files available for public use. They contain...

  4. The yeast stands alone: the future of protein biologic production.

    Science.gov (United States)

    Love, Kerry R; Dalvie, Neil C; Love, J Christopher

    2017-12-22

    Yeasts are promising alternative hosts for the manufacturing of recombinant protein therapeutics because they simply and efficiently meet needs for both platform and small-market drugs. Fast accumulation of biomass and low-cost media reduce the cost-of-goods when using yeast, which in turn can enable agile, small-volume manufacturing facilities. Small, tractable yeast genomes are amenable to rapid process development, facilitating strain and product quality by design. Specifically, Pichia pastoris is becoming a widely accepted yeast for biopharmaceutical manufacturing in much of the world owing to a clean secreted product and the rapidly expanding understanding of its cell biology as a host organism. We advocate for a near term partnership spanning industry and academia to promote open source, timely development of yeast hosts. Copyright © 2017. Published by Elsevier Ltd.

  5. Performance evaluation of stand alone hybrid PV-wind generator

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H. [Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Melaka (Malaysia); Yahaya, M. S. [Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Melaka (Malaysia)

    2015-05-15

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  6. Basic Stand Alone Medicare Prescription Drug Events PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This is a Public Use File for Prescription Drug Events drawn from the 2008 Beneficiary Summary File of Medicare beneficiaries enrolled during the calendar year 2008,...

  7. PV-Battery Sizing for Stand-Alone Lighting Applications

    OpenAIRE

    Herteleer, Bert; Cappelle, Jan; Appels, Reinhart; Lefevre, Buvana; Driesen, Johan; Catthoor, Francky

    2013-01-01

    This paper presents a follow-up and addition to a system sizing spreadsheet, detailed in [An autonomous photovoltaic system sizing program for office applications in Africa], with a focus on sizing or verifying the employability of an off-grid PV-battery system for night lighting. A dimensionless criterion, the Battery Usable Fraction UF_batt is defined, which aids both the calculations of systems and allows an approximate comparison of batteries, regardless of the employed battery chemistry....

  8. She stands alone: Pakistani woman film director, Shireen Pasha.

    Science.gov (United States)

    Mustafa, A

    1995-01-01

    This article describes the activities of film director Shireen Pasha in promoting truth in the mass media in Pakistan. Pasha is described as one who finds it inexcusable in a state-subsidized system that national problems of poverty are not aired openly. Pasha has pursued the goal of exposing the real lives of Pakistanis on film in contrast to the publicly aired segments of "pretty girls in nice drawing rooms." Foreign channels available through satellite communications technology are viewed by Pasha as inappropriate with regard to people's needs and uncreative. Pakistan began with one channel, PTV, which recently refused to air her documentary on living conditions in Pakistan's rural areas "The Travelogue Pakistan." "The Walled City of Lahore" was her film about life in the old city. Both films poetically depicted the honor of humans and their struggle to stay alive. Some of her documentaries are made to show the value of indigenous skills, centuries old know-how, and traditions, regardless of the poverty. Pasha is described as fighting with PTV management over use of resources. Pasha desires to invest in training people to do documentaries or be more field-oriented rather than investing in equipment. Pasha joined PTV in 1975 and left in 1990. Pasha is recognized for her isolation as a woman in the business world, her commitment to exposing remote cultures and truth, and the odds she must confront in attaining her goals. Pasha is committed to doing extensive research, usually conducted during the summer months, in order to construct a credible story line that is produced usually during the winter months. One model of film story line is defined as one where women are portrayed as starting from an indigenous skill or knowledge and shifting to a greater position of power and control over their lives. Pasha believes that people who make films have the responsibility to evoke a reaction in people and to offer solutions. Two acclaimed films, which were supported by USAID and the government, were "Before It's Too Late" and "Only One Way." Both deal with resource issues and the environment. She is currently director of her own film house, The Film Makers, in Lahore. After graduating from the National College of Arts in 1968, she furthered her education in the US in the history of art.

  9. Constraining lidar stand-alone retrievals with lunar photometry measurements

    Science.gov (United States)

    Ortiz-Amezcua, Pablo; Luis Guerrero-Rascado, Juan; Antonio Benavent-Oltra, Jose; Román, Roberto; Böckmann, Christine; Alados-Arboledas, Lucas

    2018-04-01

    This study combines atmospheric optical information measured with lidar and nocturnal photometers in order to find configurations that allow for the retrieval of particle microphysical properties without "3+2" lidar setups. It has been carried out using data measured at the EARLINET Granada station during the experimental campaign SLOPE in the framework of ACTRIS-2 project.

  10. The cost-effectiveness of interbody fusions versus posterolateral fusions in 137 patients with lumbar spondylolisthesis.

    Science.gov (United States)

    Bydon, Mohamad; Macki, Mohamed; Abt, Nicholas B; Witham, Timothy F; Wolinsky, Jean-Paul; Gokaslan, Ziya L; Bydon, Ali; Sciubba, Daniel M

    2015-03-01

    Reimbursements for interbody fusions have declined recently because of their questionable cost-effectiveness. A Markov model was adopted to compare the cost-effectiveness of posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (/TLIF) versus noninterbody fusion and posterolateral fusion (PLF) in patients with lumbar spondylolisthesis. Decision model analysis based on retrospective data from a single institutional series. One hundred thirty-seven patients underwent first-time instrumented lumbar fusions for degenerative or isthmic spondylolisthesis. Quality of life adjustments and expenditures were assigned to each short-term complication (durotomy, surgical site infection, and medical complication) and long-term outcome (bowel/bladder dysfunction and paraplegia, neurologic deficit, and chronic back pain). Patients were divided into a PLF cohort and a PLF plus PLIF/TLIF cohort. Anterior techniques and multilevel interbody fusions were excluded. Each short-term complication and long-term outcome was assigned a numerical quality-adjusted life-year (QALY), based on time trade-off values in the Beaver Dam Health Outcomes Study. The cost data for short-term complications were calculated from charges accrued by the institution's finance sector, and the cost data for long-term outcomes were estimated from the literature. The difference in cost of PLF plus PLIF/TLIF from the cost of PLF alone divided by the difference in QALY equals the cost-effectiveness ratio (CER). We do not report any study funding sources or any study-specific appraisal of potential conflict of interest-associated biases in this article. Of 137 first-time lumbar fusions for spondylolisthesis, 83 patients underwent PLF and 54 underwent PLIF/TLIF. The average time to reoperation was 3.5 years. The mean QALY over 3.5 years was 2.81 in the PLF cohort versus 2.66 in the PLIFo/TLIF cohort (p=.110). The mean 3.5-year costs of $54,827.05 after index interbody fusion were

  11. Cathodoluminescence of cubic boron nitride

    International Nuclear Information System (INIS)

    Tkachev, V.D.; Shipilo, V.B.; Zaitsev, A.M.

    1985-01-01

    Three types of optically active defect were observed in single-crystal and polycrystalline cubic boron nitride (β-BN). An analysis of the temperature dependences of the intensity, half-width, and energy shift of a narrow zero-phonon line at 1.76 eV (GC-1 center) made it possible to interpret the observed cathodoluminescence spectra as an optical analog of the Moessbauer effect. A comparison of the results obtained in the present study with the available data on diamond single crystals made it possible to identify the observed GC-1 center as a nitrogen vacancy. It was concluded that optical Moessbauer-type spectra can be used to analyze structure defects in the crystal lattice of β-BN

  12. Martensitic cubic → tetragonal transition

    International Nuclear Information System (INIS)

    Schumann, H.

    1983-01-01

    Indium-thallium alloys containing 14 to 30% At. Tl have a cubic face-centred beta phase wich changes into a tetragonal face-centred alpha martensite during solidification. The martensite contains twin crystals that are large enough to be seen by means of a light microscope. The phenomenological crystallographic martensite theory was used to calculate Miller's index of the habit plane, the formation of the surface relief, the orientation relations and the critical thickness ratio of the twins. In a beta monocrystal frequently only one of the 24 crystallographic possible habit planes are formed at one end of the sample and migrate through the whole crystal when the temperature drops. Externally applied tension and compression influence in different ways the direction in which the habit plane moves and can even destroy the twinned structure, i.e. they can modify the substructure of the martensite crystal. This induces superelasticity, an effect that has also been described quantitatively. (author)

  13. Comparison Between Posterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion for the Treatment of Lumbar Degenerative Diseases: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Lan, Tao; Hu, Shi-Yu; Zhang, Yuan-Tao; Zheng, Yu-Chen; Zhang, Rui; Shen, Zhe; Yang, Xin-Jian

    2018-04-01

    To compare the efficacy and safety in the management of lumbar diseases performed by either posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF). Interbody fusion is considered the "gold standard" in the treatment of lumbar degenerative diseases. Both PLIF and TLIF have been advocated, and it remains controversial as to the best operative technique. The electronic databases including Embase, PubMed, and Cochrane library were searched to identify relevant studies up to September 2017. The primary outcomes were fusion rate, complications, and clinical satisfaction. The secondary outcomes were length of hospitalization, operation time, blood loss, postoperative visual analog scale, Oswestry Disability Index, and Japanese Orthopaedic Association Score. Data analysis was conducted with RevMan 5.3 software. A total of 16 studies involving 1502 patients (805 patients in PLIF group and 697 in TLIF group) were included in the meta-analysis. The pooled analysis showed that there was no significant difference in terms of fusion rate (P > 0.05) and clinical satisfaction (P > 0.05) between the 2 groups. TLIF was superior to PLIF with significantly lower incidence of nerve root injury (P 0.05) and graft malposition (P > 0.05). PLIF required significant longer operation time (P degenerative lumbar diseases. However, TLIF was superior to PLIF with shorter operation time, less blood loss, and lower incidence of nerve root injury and dural tear. There is no significant difference between both groups regarding wound infection and graft malposition. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Biomechanical evaluation of a spherical lumbar interbody device at varying levels of subsidence.

    Science.gov (United States)

    Rundell, Steven A; Isaza, Jorge E; Kurtz, Steven M

    2011-01-01

    Ulf Fernström implanted stainless steel ball bearings following discectomy, or for painful disc disease, and termed this procedure disc arthroplasty. Today, spherical interbody spacers are clinically available, but there is a paucity of associated biomechanical testing. The primary objective of the current study was to evaluate the biomechanics of a spherical interbody implant. It was hypothesized that implantation of a spherical interbody implant, with combined subsidence into the vertebral bodies, would result in similar ranges of motion (RoM) and facet contact forces (FCFs) when compared with an intact condition. A secondary objective of this study was to determine the effect of using a polyetheretherketone (PEEK) versus a cobalt chrome (CoCr) implant on vertebral body strains. We hypothesized that the material selection would have a negligible effect on vertebral body strains since both materials have elastic moduli substantially greater than the annulus. A finite element model of L3-L4 was created and validated by use of ROM, disc pressure, and bony strain from previously published data. Virtual implantation of a spherical interbody device was performed with 0, 2, and 4 mm of subsidence. The model was exercised in compression, flexion, extension, axial rotation, and lateral bending. The ROM, vertebral body effective (von Mises) strain, and FCFs were reported. Implantation of a PEEK implant resulted in slightly lower strain maxima when compared with a CoCr implant. For both materials, the peak strain experienced by the underlying bone was reduced with increasing subsidence. All levels of subsidence resulted in ROM and FCFs similar to the intact model. The results suggest that a simple spherical implant design is able to maintain segmental ROM and provide minimal differences in FCFs. Large areas of von Mises strain maxima were generated in the bone adjacent to the implant regardless of whether the implant was PEEK or CoCr.

  15. Do Lordotic Cages Provide Better Segmental Lordosis Versus Nonlordotic Cages in Lateral Lumbar Interbody Fusion (LLIF)?

    Science.gov (United States)

    Sembrano, Jonathan N; Horazdovsky, Ryan D; Sharma, Amit K; Yson, Sharon C; Santos, Edward R G; Polly, David W

    2017-05-01

    A retrospective comparative radiographic review. To evaluate the radiographic changes brought about by lordotic and nonlordotic cages on segmental and regional lumbar sagittal alignment and disk height in lateral lumbar interbody fusion (LLIF). The effects of cage design on operative level segmental lordosis in posterior interbody fusion procedures have been reported. However, there are no studies comparing the effect of sagittal implant geometry in LLIF. This is a comparative radiographic analysis of consecutive LLIF procedures performed with use of lordotic and nonlordotic interbody cages. Forty patients (61 levels) underwent LLIF. Average age was 57 years (range, 30-83 y). Ten-degree lordotic PEEK cages were used at 31 lumbar interbody levels, and nonlordotic cages were used at 30 levels. The following parameters were measured on preoperative and postoperative radiographs: segmental lordosis; anterior and posterior disk heights at operative level; segmental lordosis at supra-level and subjacent level; and overall lumbar (L1-S1) lordosis. Measurement changes for each cage group were compared using paired t test analysis. The use of lordotic cages in LLIF resulted in a significant increase in lordosis at operative levels (2.8 degrees; P=0.01), whereas nonlordotic cages did not (0.6 degrees; P=0.71) when compared with preoperative segmental lordosis. Anterior and posterior disk heights were significantly increased in both groups (Plordosis (lordotic P=0.86 vs. nonlordotic P=0.25). Lordotic cages provided significant increase in operative level segmental lordosis compared with nonlordotic cages although overall lumbar lordosis remained unchanged. Anterior and posterior disk heights were significantly increased by both cages, providing basis for indirect spinal decompression.

  16. Segmental and global lordosis changes with two-level axial lumbar interbody fusion and posterior instrumentation

    Science.gov (United States)

    Melgar, Miguel A; Tobler, William D; Ernst, Robert J; Raley, Thomas J; Anand, Neel; Miller, Larry E; Nasca, Richard J

    2014-01-01

    Background Loss of lumbar lordosis has been reported after lumbar interbody fusion surgery and may portend poor clinical and radiographic outcome. The objective of this research was to measure changes in segmental and global lumbar lordosis in patients treated with presacral axial L4-S1 interbody fusion and posterior instrumentation and to determine if these changes influenced patient outcomes. Methods We performed a retrospective, multi-center review of prospectively collected data in 58 consecutive patients with disabling lumbar pain and radiculopathy unresponsive to nonsurgical treatment who underwent L4-S1 interbody fusion with the AxiaLIF two-level system (Baxano Surgical, Raleigh NC). Main outcomes included back pain severity, Oswestry Disability Index (ODI), Odom's outcome criteria, and fusion status using flexion and extension radiographs and computed tomography scans. Segmental (L4-S1) and global (L1-S1) lumbar lordosis measurements were made using standing lateral radiographs. All patients were followed for at least 24 months (mean: 29 months, range 24-56 months). Results There was no bowel injury, vascular injury, deep infection, neurologic complication or implant failure. Mean back pain severity improved from 7.8±1.7 at baseline to 3.3±2.6 at 2 years (p lordosis, defined as a change in Cobb angle ≤ 5°, was identified in 84% of patients at L4-S1 and 81% of patients at L1-S1. Patients with loss or gain in segmental or global lordosis experienced similar 2-year outcomes versus those with less than a 5° change. Conclusions/Clinical Relevance Two-level axial interbody fusion supplemented with posterior fixation does not alter segmental or global lordosis in most patients. Patients with postoperative change in lordosis greater than 5° have similarly favorable long-term clinical outcomes and fusion rates compared to patients with less than 5° lordosis change. PMID:25694920

  17. Early benefits of minimally invasive transforaminal lumbar interbody fusion in comparison with the traditional open procedure

    Directory of Open Access Journals (Sweden)

    Gregor Rečnik

    2015-06-01

    Full Text Available AbstractBackgroundLumbar interbody fusion is a standard operative procedure in orthopedic spine surgery. Morphological and functional changes in the multifidus muscle after an open procedure have led to the development of a minimally invasive technique, after which no such muscle changes were observed. MethodsSixty-four patients, with clinical and radiological criteria for one-level transforaminal lumbar interbody fusion were enrolled in our prospective randomized study between December 2011 and March 2014. They were randomized into two groups: open approach (33 patients vs. minimally invasive approach (31 patients; one patient was excluded from each group due to postoperative complications. Independent samples T-test was used to compare average values of increase in creatin kinase (CK, which is an enzymatic marker of muscle injury, average surgical time, loss of blood during and after surgery, back pain according to the Visual Analogue Scale (VAS and day of discharge from the hospital. ResultsStatistically important (P< 0.001 lower blood loss (188 ml vs. 527 ml total, less CK increase (15 ukat/L vs. 29 ukat/L, lower VAS score after surgery (7.3 vs. 8.7 and earlier discharge from the hospital (3.5 days vs. 5.2 days were observed in the minimally invasive transforaminal lumbar interbody fusion group. No significant difference in average surgical time was recorded. Conclusions Our results suggest, that minimally invasive transforaminal lumbar interbody fusion causes is associated with less muscle damage, lower blood loss, less post surgical pain and faster early rehabilitation, which is in accordance with previous studies.

  18. Topics in Cubic Special Geometry

    CERN Document Server

    Bellucci, Stefano; Roychowdhury, Raju

    2011-01-01

    We reconsider the sub-leading quantum perturbative corrections to N=2 cubic special Kaehler geometries. Imposing the invariance under axion-shifts, all such corrections (but the imaginary constant one) can be introduced or removed through suitable, lower unitriangular symplectic transformations, dubbed Peccei-Quinn (PQ) transformations. Since PQ transformations do not belong to the d=4 U-duality group G4, in symmetric cases they generally have a non-trivial action on the unique quartic invariant polynomial I4 of the charge representation R of G4. This leads to interesting phenomena in relation to theory of extremal black hole attractors; namely, the possibility to make transitions between different charge orbits of R, with corresponding change of the supersymmetry properties of the supported attractor solutions. Furthermore, a suitable action of PQ transformations can also set I4 to zero, or vice versa it can generate a non-vanishing I4: this corresponds to transitions between "large" and "small" charge orbit...

  19. POSTERIOR LUMBAR INTERBODY FUSION AND INSTRUMENTED POSTEROLATERAL FUSION IN ADULT SPONDYLOLISTHESIS: ASSESSMENT AND CLINICAL OUTCOME

    Directory of Open Access Journals (Sweden)

    Rajarajan

    2015-11-01

    Full Text Available OBJECTIVE: Aim of this study is to assess and compare the outcomes of posterior lumbar interbody fusion (PLIF and posterolateral fusion (PLF in adult isthmic spondylosthesis. BACKGROUND: Posterolateral fusion has been considered the best method and widely been used for surgical treatment of adult spondylolisthesis.Superior results have subsequently been reported with interbody fusion with cages and posterior instrumentation MATERIALS AND METHODS: Thirty six patients with isthmic spondylolisthesis were operated. One group (20 patients had decompression and posterolateral fusion (PLF with a pedicle screw system; other group (16 patients was treated by decompression, posterior lumbar interbody fusion (PLIF and a Pedicle screw system. In both groups adequate decompression was done RESULTS: Seventy seven percent of the patients had a good result with (PLIF and 68 percent with posterolateral fusion (PLF. However there was no statistical difference in cases with low grade slipping, whereas the difference was significant for cases with high grade slipping. Fusion rate was 93% with (PLIF and 68% with (PLF, but without any significant incidence in the functional outcome. 78% has relief of sciatica and neurogenic claudication. CONCLUSION: Based on these findings we found that for high grade spondylolisthesis which requires reduction or if the disc space is still high posterior lumbar inter body fusion is preferable. For low grade spondylolisthesis or if the disc space is narrow posterolateral fusion is preferable. A successful result of fusion operation depends on adequate decompression which relieves radicular symptoms.

  20. Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Perspective on Current Evidence and Clinical Knowledge

    Directory of Open Access Journals (Sweden)

    Ali Habib

    2012-01-01

    Full Text Available This paper reviews the current published data regarding open transforaminal lumbar interbody fusion (TLIF in relation to minimally invasive transforaminal lumbar interbody fusion (MI-TLIF. Introduction. MI-TLIF, a modern method for lumbar interbody arthrodesis, has allowed for a minimally invasive method to treat degenerative spinal pathologies. Currently, there is limited literature that compares TLIF directly to MI-TLIF. Thus, we seek to discuss the current literature on these techniques. Methods. Using a PubMed search, we reviewed recent publications of open and MI-TLIF, dating from 2002 to 2012. We discussed these studies and their findings in this paper, focusing on patient-reported outcomes as well as complications. Results. Data found in 14 articles of the literature was analyzed. Using these reports, we found mean follow-up was 20 months. The mean patient study size was 52. Seven of the articles directly compared outcomes of open TLIF with MI-TLIF, such as mean duration of surgery, length of post-operative stay, blood loss, and complications. Conclusion. Although high-class data comparing these two techniques is lacking, the current evidence supports MI-TLIF with outcomes comparable to that of the traditional, open technique. Further prospective, randomized studies will help to further our understanding of this minimally invasive technique.

  1. Allograft Cellular Bone Matrix in Extreme Lateral Interbody Fusion: Preliminary Radiographic and Clinical Outcomes

    Directory of Open Access Journals (Sweden)

    Antoine G. Tohmeh

    2012-01-01

    Full Text Available Introduction. Extreme lateral interbody fusion (XLIF is a minimally disruptive alternative for anterior lumbar interbody fusion. Recently, synthetic and allograft materials have been increasingly used to eliminate donor-site pain and complications secondary to autogenous bone graft harvesting. The clinical use of allograft cellular bone graft has potential advantages over autograft by eliminating the need to harvest autograft while mimicking autograft's biologic function. The objective of this study was to examine 12-month radiographic and clinical outcomes in patients who underwent XLIF with Osteocel Plus, one such allograft cellular bone matrix. Methods. Forty (40 patients were treated at 61 levels with XLIF and Osteocel Plus and included in the analysis. Results. No complications were observed. From preoperative to 12-month postoperative followup, ODI improved 41%, LBP improved 55%, leg pain improved 43.3%, and QOL (SF-36 improved 56%. At 12 months, 92% reported being “very” or “somewhat” satisfied with their outcome and 86% being either “very” or “somewhat likely” to choose to undergo the procedure again. Complete fusion was observed in 90.2% (55/61 of XLIF levels. Conclusions. Complete interbody fusion with Osteocel Plus was shown in 90.2% of XLIF levels, with the remaining 9.8% being partially consolidated and progressing towards fusion at 12 months.

  2. Cubical local partial orders on cubically subdivided spaces - existence and construction

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth

    The geometric models of Higher Dimensional Automata and Dijkstra's PV-model are cubically subdivided topological spaces with a local partial order. If a cubicalization of a topological space is free of immersed cubic Möbius bands, then there are consistent choices of direction in all cubes, such ...... that the underlying geometry of an HDA may be quite complicated....

  3. Cubical local partial orders on cubically subdivided spaces - Existence and construction

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth

    2006-01-01

    The geometric models of higher dimensional automata (HDA) and Dijkstra's PV-model are cubically subdivided topological spaces with a local partial order. If a cubicalization of a topological space is free of immersed cubic Möbius bands, then there are consistent choices of direction in all cubes...... that the underlying geometry of an HDA may be quite complicated....

  4. One-Level or Multilevel Interbody Fusion for Multilevel Lumbar Degenerative Diseases: A Prospective Randomized Control Study with a 4-Year Follow-Up.

    Science.gov (United States)

    Li, Tiefeng; Shi, Lei; Luo, Yibin; Chen, Deyu; Chen, Yu

    2018-02-01

    The treatment of multilevel lumbar degenerative disease (LDD) is complicated and challenging, and the optimal surgical strategy remains controversial. To compare the differences in clinical and radiologic outcomes and in complications after 1-level interbody fusion versus multilevel interbody fusion for the treatment of multilevel LDD. A total of 100 patients with multilevel LDD were randomized in a 1:1 ratio into the 1-level interbody fusion group or the multilevel interbody fusion group. Clinical and radiologic results and major complications in the 2 groups were analyzed. Clinical outcomes were assessed using the Visual Analog Scale for radicular and back pain, the Oswestry Disability Index, and the short-form 36 physical score. Clinical status was assessed by the Whitecloud classification. Radiologic evaluation included assessment of lumbar lordosis, pelvic incidence, and sacral slope. There were no significant differences in clinical and radiologic results between the 2 groups. Procedure duration and intraoperative blood loss were significantly greater in the multilevel interbody fusion group than in the 1-level interbody fusion group; the multilevel interbody fusion group also had greater incidences of temporary nerve root palsy, wound infection, and adjacent segment disease. A hybrid technique including 1-level interbody fusion and multilevel posterolateral fusion is recommended for patients with multilevel LDD. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis and degenerative spondylosis: 5-year results.

    Science.gov (United States)

    Park, Yung; Ha, Joong Won; Lee, Yun Tae; Sung, Na Young

    2014-06-01

    Multiple studies have reported favorable short-term results after treatment of spondylolisthesis and other degenerative lumbar diseases with minimally invasive transforaminal lumbar interbody fusion. However, to our knowledge, results at a minimum of 5 years have not been reported. We determined (1) changes to the Oswestry Disability Index, (2) frequency of radiographic fusion, (3) complications and reoperations, and (4) the learning curve associated with minimally invasive transforaminal lumbar interbody fusion at minimum 5-year followup. We reviewed our first 124 patients who underwent minimally invasive transforaminal lumbar interbody fusion to treat low-grade spondylolisthesis and degenerative lumbar diseases and did not need a major deformity correction. This represented 63% (124 of 198) of the transforaminal lumbar interbody fusion procedures we performed for those indications during the study period (2003-2007). Eighty-three (67%) patients had complete 5-year followup. Plain radiographs and CT scans were evaluated by two reviewers. Trends of surgical time, blood loss, and hospital stay over time were examined by logarithmic curve fit-regression analysis to evaluate the learning curve. At 5 years, mean Oswestry Disability Index improved from 60 points preoperatively to 24 points and 79 of 83 patients (95%) had improvement of greater than 10 points. At 5 years, 67 of 83 (81%) achieved radiographic fusion, including 64 of 72 patients (89%) who had single-level surgery. Perioperative complications occurred in 11 of 124 patients (9%), and another surgical procedure was performed in eight of 124 patients (6.5%) involving the index level and seven of 124 patients (5.6%) at adjacent levels. There were slowly decreasing trends of surgical time and hospital stay only in single-level surgery and almost no change in intraoperative blood loss over time, suggesting a challenging learning curve. Oswestry Disability Index scores improved for patients with spondylolisthesis

  6. Cubical sets as a classifying topos

    DEFF Research Database (Denmark)

    Spitters, Bas

    Coquand’s cubical set model for homotopy type theory provides the basis for a computational interpretation of the univalence axiom and some higher inductive types, as implemented in the cubical proof assistant. We show that the underlying cube category is the opposite of the Lawvere theory of De...... Morgan algebras. The topos of cubical sets itself classifies the theory of ‘free De Morgan algebras’. This provides us with a topos with an internal ‘interval’. Using this interval we construct a model of type theory following van den Berg and Garner. We are currently investigating the precise relation...

  7. Generalized Vaidya spacetime for cubic gravity

    Science.gov (United States)

    Ruan, Shan-Ming

    2016-03-01

    We present a kind of generalized Vaidya solution of a new cubic gravity in five dimensions whose field equations in spherically symmetric spacetime are always second order like the Lovelock gravity. We also study the thermodynamics of its spherically symmetric apparent horizon and get its entropy expression and generalized Misner-Sharp energy. Finally, we present the first law and second law hold in this gravity. Although all the results are analogous to those in Lovelock gravity, we in fact introduce the contribution of a new cubic term in five dimensions where the cubic Lovelock term is just zero.

  8. Cubic Pencils and Painlev\\'e Hamiltonians

    OpenAIRE

    Kajiwara, Kenji; Masuda, Tetsu; Noumi, Masatoshi; Ohta, Yasuhiro; Yamada, Yasuhiko

    2004-01-01

    We present a simple heuristic method to derive the Painlev\\'e differential equations from the corresponding geometry of rational surafces. We also give a direct relationship between the cubic pencils and Seiberg-Witten curves.

  9. A Note on Cubic Convolution Interpolation

    OpenAIRE

    Meijering, E.; Unser, M.

    2003-01-01

    We establish a link between classical osculatory interpolation and modern convolution-based interpolation and use it to show that two well-known cubic convolution schemes are formally equivalent to two osculatory interpolation schemes proposed in the actuarial literature about a century ago. We also discuss computational differences and give examples of other cubic interpolation schemes not previously studied in signal and image processing.

  10. Cubical version of combinatorial differential forms

    DEFF Research Database (Denmark)

    Kock, Anders

    2010-01-01

    The theory of combinatorial differential forms is usually presented in simplicial terms. We present here a cubical version; it depends on the possibility of forming affine combinations of mutual neighbour points in a manifold, in the context of synthetic differential geometry.......The theory of combinatorial differential forms is usually presented in simplicial terms. We present here a cubical version; it depends on the possibility of forming affine combinations of mutual neighbour points in a manifold, in the context of synthetic differential geometry....

  11. Titanium vs. polyetheretherketone (PEEK) interbody fusion: Meta-analysis and review of the literature.

    Science.gov (United States)

    Seaman, Scott; Kerezoudis, Panagiotis; Bydon, Mohamad; Torner, James C; Hitchon, Patrick W

    2017-10-01

    Spinal interbody fusion is a standard and accepted method for spinal fusion. Interbody fusion devices include titanium (Ti) and polyetheretherketone (PEEK) cages with distinct biomechanical properties. Titanium and PEEK cages have been evaluated in the cervical and lumbar spine, with conflicting results in bony fusion and subsidence. Using Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, we reviewed the available literature evaluating Ti and PEEK cages to assess subsidence and fusion rates. Six studies were included in the analysis, 3 of which were class IV evidence, 2 were class III, and 1 was class II. A total of 410 patients (Ti-228, PEEK-182) and 587 levels (Ti-327, PEEK-260) were studied. Pooled mean age was 50.8years in the Ti group, and 53.1years in the PEEK group. Anterior cervical discectomy was performed in 4 studies (395 levels) and transforaminal interbody fusion in 2 studies (192 levels). No statistically significant difference was found between groups with fusion (OR 1.16, 95% C.I 0.59-2.89, p=0.686, I 2 =49.7%) but there was a statistically significant the rate of subsidence with titanium (OR 3.59, 95% C.I 1.28-10.07, p=0.015, I 2 =56.9%) at last follow-up. Titanium and PEEK cages are associated with a similar rate of fusion, but there is an increased rate of subsidence with titanium cage. Future prospective randomized controlled trials are needed to further evaluate these cages using surgical and patient-reported outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Comparison of Clinical and Radiologic Results of Mini-Open Transforaminal Lumbar Interbody Fusion and Extreme Lateral Interbody Fusion Indirect Decompression for Degenerative Lumbar Spondylolisthesis.

    Science.gov (United States)

    Kono, Yutaka; Gen, Hogaku; Sakuma, Yoshio; Koshika, Yasuhide

    2018-04-01

    Retrospective study. In this study, we compared the postoperative outcomes of extreme lateral interbody fusion (XLIF) indirect decompression with that of mini-open transforaminal lumbar interbody fusion (TLIF) in patients with lumbar degenerative spondylolisthesis. There are very few reports examining postoperative results of XLIF and minimally invasive TLIF for degenerative lumbar spondylolisthesis, and no reports comparing XLIF and mini-open TLIF. Forty patients who underwent 1-level spinal fusion, either by XLIF indirect decompression (X group, 20 patients) or by mini-open TLIF (T group, 20 patients), for treatment of lumbar degenerative spondylolisthesis were included in this study. Invasiveness of surgery was evaluated on the basis of surgery time, blood loss, hospitalization period, and perioperative complications. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ), disc angle (DA), disc height (DH), and slipping length (SL) were evaluated before surgery, immediately after surgery, and at 12 months after surgery. Cross-sectional spinal canal area (CSA) was also measured before surgery and at 1 month after surgery. There was no significant difference between the groups in terms of surgery time or hospitalization period; however, X group showed a significant decrease in blood loss ( p X group ( p <0.05), and the changes in DA and SL were not significantly different between the two groups. The change in CSA was significantly greater in the T group ( p <0.001). Postoperative clinical results were equally favorable for both procedures; however, in comparison with mini-open TLIF, less blood loss and greater correction of DH were observed in XLIF.

  13. An analysis of postoperative thigh symptoms after minimally invasive transpsoas lumbar interbody fusion.

    Science.gov (United States)

    Cummock, Matthew D; Vanni, Steven; Levi, Allan D; Yu, Yong; Wang, Michael Y

    2011-07-01

    The minimally invasive transpsoas interbody fusion technique requires dissection through the psoas muscle, which contains the nerves of the lumbosacral plexus posteriorly and genitofemoral nerve anteriorly. Retraction of the psoas is becoming recognized as a cause of transient postoperative thigh pain, numbness, paresthesias, and weakness. However, few reports have described the nature of thigh symptoms after this procedure. The authors performed a review of patients who underwent the transpsoas technique for lumbar spondylotic disease, disc degeneration, and spondylolisthesis treated at a single academic medical center. A review of patient charts, including the use of detailed patient-driven pain diagrams performed at equal preoperative and follow-up intervals, investigated the survival of postoperative thigh pain, numbness, paresthesias, and weakness of the iliopsoas and quadriceps muscles in the follow-up period on the ipsilateral side of the surgical approach. Over a 3.2-year period, 59 patients underwent transpsoas interbody fusion surgery. Of these, 62.7% had thigh symptoms postoperatively. New thigh symptoms at first follow-up visit included the following: burning, aching, stabbing, or other pain (39.0%); numbness (42.4%); paresthesias (11.9%); and weakness (23.7%). At 3 months postoperatively, these percentages decreased to 15.5%, 24.1%, 5.6%, and 11.3%, respectively. Within the patient sample, 44% underwent a 1-level, 41% a 2-level, and 15% a 3-level transpsoas operation. While not statistically significant, thigh pain, numbness, and weakness were most prevalent after L4-5 transpsoas interbody fusion at the first postoperative follow-up. The number of lumbar levels that were surgically treated had no clear association with thigh symptoms but did correlate directly with surgical time, intraoperative blood loss, and length of hospital stay. Transpsoas interbody fusion is associated with high rates of immediate postoperative thigh symptoms. While larger

  14. Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion.

    Science.gov (United States)

    Madan, S S; Boeree, N R

    2003-12-01

    Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (scorelife questionnaire) score of 71.8% (28 patients) in

  15. Alternative route of process modification for biofuel production by embedding the Fischer–Tropsch plant in existing stand-alone power plant (10 MW) based on biomass gasification – Part I: A conceptual modeling and simulation approach (a case study in Thailand)

    International Nuclear Information System (INIS)

    Hunpinyo, Piyapong; Cheali, Peam; Narataruksa, Phavanee; Tungkamani, Sabaithip; Chollacoop, Nuwong

    2014-01-01

    Graphical abstract: SynBiofuel production through existing gasification plants in Thailand, using waste agricultural biomass as raw material, was studied. The process design was initiated conceptually in the areas of gas phase reaction system via Fischer-Tropsch (FT) synthesis. The development of FT configurations on syngas conversion to transportation fuels (e.g., diesel range) was investigated. In order to develop a techno-economic assessment, the three different capacities corresponding to 1 MW, 2 MW and 3 MW based on thermal input of syngas were evaluated. Once-through FT concept was proposed in which the unconverted syngas was combusted with air in an externally fired gas turbine (EFGT) to produce surplus electricity. The results of process simulation were discussed open-mindedly including the overall plant design and energy efficiency. Preliminary economics, and some site specific situations under which additional capital cost savings on existing infrastructure was realized. - Highlights: • Experimental results were used and integrated with a reactor model for SynBiofuel. • Process simulation with the lumped reaction rate was used to achieve accurate results. • Process simulation was performed using ASPEN Plus to design FT configurations. • Maximum energy FT efficiency was approximately 37%. • Economic potential was computed by ROI and PBP resulting in the attractive solutions. - Abstract: The utilization of syngas shows a highly potential to improve the economic potential of the stand-alone power unit-based gasification plants as well as enhancing the growing demand of transportation fuels. The thermochemical conversion of biomass via gasification to heat and power generations from the earlier study is further enhanced by integrating Fischer–Tropsch (FT) synthesis with the existing gasification pilot scale studied previously. To support the potential and perspectives in major economies due to scaling up in developing countries such as Thailand

  16. Rational decision making in a wide scenario of different minimally invasive lumbar interbody fusion approaches and devices.

    Science.gov (United States)

    Pimenta, Luiz; Tohmeh, Antoine; Jones, David; Amaral, Rodrigo; Marchi, Luis; Oliveira, Leonardo; Pittman, Bruce C; Bae, Hyun

    2018-03-01

    With the proliferation of a variety of modern MIS spine surgery procedures, it is mandatory that the surgeon dominate all aspects involved in surgical indication. The information related to the decision making in patient selection for specific procedures is mandatory for surgical success. The objective of this study is to present decision-making criteria in minimally invasive surgery (MIS) selection for a variety of patients and pathologies. In this article, practicing surgeons who specialize in various MIS approaches for spinal fusion were engaged to provide expert opinion and literature review on decision making criteria for several MIS procedures. Pros, cons, relative limitations, and case examples are provided for patient selection in treatment with MIS posterolateral fusion (MIS-PLF), mini anterior lumbar interbody fusion (mini-ALIF), lateral interbody fusion (LLIF), MIS posterior lumbar interbody fusion (MIS-PLIF) and MIS transforaminal lumbar interbody fusion (MIS-TLIF). There is a variety of aspects to consider when deciding which modern MIS surgical approach is most appropriate to use based on patient and pathologic characteristics. The surgeon must adapt them to the characteristic of each type of patients, helping them to choose the most effective and efficient therapeutic option for each case.

  17. Purely cubic action for string field theory

    Science.gov (United States)

    Horowitz, G. T.; Lykken, J.; Rohm, R.; Strominger, A.

    1986-01-01

    It is shown that Witten's (1986) open-bosonic-string field-theory action and a closed-string analog can be written as a purely cubic interaction term. The conventional form of the action arises by expansion around particular solutions of the classical equations of motion. The explicit background dependence of the conventional action via the Becchi-Rouet-Stora-Tyutin operator is eliminated in the cubic formulation. A closed-form expression is found for the full nonlinear gauge-transformation law.

  18. Nonlinear dynamics of quadratically cubic systems

    International Nuclear Information System (INIS)

    Rudenko, O V

    2013-01-01

    We propose a modified form of the well-known nonlinear dynamic equations with quadratic relations used to model a cubic nonlinearity. We show that such quadratically cubic equations sometimes allow exact solutions and sometimes make the original problem easier to analyze qualitatively. Occasionally, exact solutions provide a useful tool for studying new phenomena. Examples considered include nonlinear ordinary differential equations and Hopf, Burgers, Korteweg–de Vries, and nonlinear Schrödinger partial differential equations. Some problems are solved exactly in the space–time and spectral representations. Unsolved problems potentially solvable by the proposed approach are listed. (methodological notes)

  19. Clinical Outcomes of Extreme Lateral Interbody Fusion in the Treatment of Adult Degenerative Scoliosis

    Directory of Open Access Journals (Sweden)

    Adam M. Caputo

    2012-01-01

    Full Text Available Introduction. The use of extreme lateral interbody fusion (XLIF and other lateral access surgery is rapidly increasing in popularity. However, limited data is available regarding its use in scoliosis surgery. The objective of this study was to evaluate the clinical outcomes of adults with degenerative lumbar scoliosis treated with XLIF. Methods. Thirty consecutive patients with adult degenerative scoliosis treated by a single surgeon at a major academic institution were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Validated clinical outcome scores were obtained on patients preoperatively and at most recent follow-up. Complications were recorded. Results. The study group demonstrated improvement in multiple clinical outcome scores. Oswestry Disability Index scores improved from 24.8 to 19.0 (P < 0.001. Short Form-12 scores improved, although the change was not significant. Visual analog scores for back pain decreased from 6.8 to 4.6 (P < 0.001 while scores for leg pain decreased from 5.4 to 2.8 (P < 0.001. A total of six minor complications (20% were recorded, and two patients (6.7% required additional surgery. Conclusions. Based on the significant improvement in validated clinical outcome scores, XLIF is effective in the treatment of adult degenerative scoliosis.

  20. Lateral retroperitoneal transpsoas interbody fusion in a patient with achondroplastic dwarfism.

    Science.gov (United States)

    Staub, Blake N; Holman, Paul J

    2015-02-01

    The authors present the first reported use of the lateral retroperitoneal transpsoas approach for interbody arthrodesis in a patient with achondroplastic dwarfism. The inherent anatomical abnormalities of the spine present in achondroplastic dwarfism predispose these patients to an increased incidence of spinal deformity as well as neurogenic claudication and potential radicular symptoms. The risks associated with prolonged general anesthesia and intolerance of significant blood loss in these patients makes them ideal candidates for minimally invasive spinal surgery. The patient in this case was a 51-year-old man with achondroplastic dwarfism who had a history of progressive claudication and radicular pain despite previous extensive lumbar laminectomies. The lateral retroperitoneal transpsoas approach was used for placement of interbody cages at L1/2, L2/3, L3/4, and L4/5, followed by posterior decompression and pedicle screw instrumentation. The patient tolerated the procedure well with no complications. Postoperatively his claudicatory and radicular symptoms resolved and a CT scan revealed solid arthrodesis with no periimplant lucencies.

  1. Single-stage transforaminal decompression, debridement, interbody fusion, and posterior instrumentation for lumbosacral brucellosis.

    Science.gov (United States)

    Abulizi, Yakefu; Liang, Wei-Dong; Muheremu, Aikeremujiang; Maimaiti, Maierdan; Sheng, Wei-Bin

    2017-07-14

    Spinal brucellosis is a less commonly reported infectious spinal pathology. There are few reports regarding the surgical treatment of spinal brucellosis in existing literature. This retrospective study was conducted to determine the effectiveness of single-stage transforaminal decompression, debridement, interbody fusion, and posterior instrumentation for lumbosacral spinal brucellosis. From February 2012 to April 2015, 32 consecutive patients (19 males and 13 females, mean age 53.7 ± 8.7) with lumbosacral brucellosis treated by transforaminal decompression, debridement, interbody fusion, and posterior instrumentation were enrolled. Medical records, imaging studies, laboratory data were collected and summarized. Surgical outcomes were evaluated based on visual analogue scale (VAS), Oswestry Disability Index (ODI) and Japanese Orthopaedic Association (JOA) scale. The changes in C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), clinical symptoms and complications were investigated. Graft fusion was evaluated using Bridwell grading criteria. The mean follow-up period was 24.9 ± 8.2 months. Back pain and radiating leg pain was relieved significantly in all patients after operation. No implant failures were observed in any patients. Wound infection was observed in two patients and sinus formation was observed in one patient. Solid bony fusion was achieved in 30 patients and the fusion rate was 93.8%. The levels of ESR and CRP were returned to normal by the end of three months' follow-up. VAS and ODI scores were significantly improved (P brucellosis.

  2. Custom-Made Titanium 3-Dimensional Printed Interbody Cages for Treatment of Osteoporotic Fracture-Related Spinal Deformity.

    Science.gov (United States)

    Siu, Timothy L; Rogers, Jeffrey M; Lin, Kainu; Thompson, Robert; Owbridge, Mark

    2018-03-01

    Advances in minimally invasive interbody fusion have greatly enhanced surgeons' capability to correct adult spinal deformity with reduced morbidity. However, the feasibility of such approaches is limited in patients with previous osteoporotic fractures as the resultant vertebral deformity renders the end plate geometry incongruous with conventional interbody implants. Current 3-dimensional (3D) printing technology offers a novel solution by fabricating custom-made implants tailored to individual anatomy. We present the results of a patient with osteoporotic lumbar fractures treated by such technology. A 74-year-old woman, with previous osteoporotic fractures at L2 and L3 resulting in concave deformity of the end plates, presented with intractable radiculopathy secondary to lateral recess and foraminal stenosis (L2-3 and L3-4). A minimally invasive lateral lumbar interbody fusion at L2-3 and L3-4 was considered favorable, but due to the associated vertebral collapse, off-the-shelf implants were not compatible with patient anatomy. In silico simulation based on preoperative computed tomography (CT) imaging was thus conducted to design customized cages to cater for the depressed recipient end plates and vertebral loss. The design was converted to implantable titanium cages through 3D additive manufacturing. At surgery, a tight fit between the implants and the targeted disk space was achieved. Postoperative CT scan confirmed excellent implant-end plate matching and restoration of lost disk space. The patient began to ambulate from postoperative day 1 and at 6-month follow-up resolution of radicular symptoms and CT evidence of interbody fusion were recorded. 3D-printed custom-made interbody cages can help overcome the difficulties in deformity correction secondary to osteoporotic fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Dipaths and dihomotopies in a cubical complex

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth

    2005-01-01

    In the geometric realization of a cubical complex without degeneracies, a $\\Box$-set, dipaths and dihomotopies may not be combinatorial, i.e., not geometric realizations of combinatorial dipaths and equivalences. When we want to use geometric/topological tools to classify dipaths on the 1-skeleton...

  4. Some elements go cubic under pressure

    Czech Academy of Sciences Publication Activity Database

    Legut, Dominik

    2007-01-01

    Roč. 60, č. 10 (2007), s. 17-17 ISSN 0031-9228 Institutional research plan: CEZ:AV0Z20410507 Keywords : ab initio * polonium * cubic structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.133, year: 2007

  5. The Exact Limit of Some Cubic Towers

    DEFF Research Database (Denmark)

    Anbar Meidl, Nurdagül; Beelen, Peter; Nguyen, Nhut

    2017-01-01

    Recently, a new explicit tower of function fields was introduced by Bassa, Beelen, Garcia and Stichtenoth (BBGS). This resulted in currently the best known lower bound for Ihara’s constant in the case of non-prime finite fields. In particular over cubic fields, the tower’s limit is at least as go...

  6. 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...

  7. Axial lumbar interbody fusion: a 6-year single-center experience

    Directory of Open Access Journals (Sweden)

    Zeilstra DJ

    2013-08-01

    Full Text Available Dick J Zeilstra,1 Larry E Miller,2,3 Jon E Block3 1Bergman Clinics, Naarden and NedSpine, Ede, The Netherlands; 2Miller Scientific Consulting, Inc, Arden, NC, USA; 3The Jon Block Group, San Francisco, CA, USA Introduction: The aim of this study is to report our 6-year single-center experience with L5–S1 axial lumbar interbody fusion (AxiaLIF. Methods: A total of 131 patients with symptomatic degenerative disc disease refractory to nonsurgical treatment were treated with AxiaLIF at L5–S1, and were followed for a minimum of 1 year (mean: 21 months. Main outcomes included back and leg pain severity, Oswestry Disability Index score, working status, analgesic medication use, patient satisfaction, and complications. Computed tomography was used to determine postoperative fusion status. Results: No intraoperative complications, including vascular, neural, urologic, or bowel injuries, were reported. Back and leg pain severity decreased by 51% and 42%, respectively, during the follow-up period (both P < 0.001. Back function scores improved 50% compared to baseline. Clinical success, defined as improvement ≥30%, was 67% for back pain severity, 65% for leg pain severity, and 71% for back function. The employment rate increased from 47% before surgery to 64% at final follow-up (P < 0.001. Less than one in four patients regularly used analgesic medications postsurgery. Patient satisfaction with the AxiaLIF procedure was 83%. The fusion rate was 87.8% at final follow-up. During follow-up, 17 (13.0% patients underwent 18 reoperations on the lumbar spine, including pedicle screw fixation (n = 10, total disc replacement of an uninvolved level (n = 3, facet screw fixation (n = 3, facet screw removal (n = 1, and interbody fusion at L4–L5 (n = 1. Eight (6.1% reoperations were at the index level. Conclusion: Single-level AxiaLIF is a safe and effective means to achieve lumbosacral fusion in patients with symptomatic degenerative disc disease. Keywords: Axia

  8. Minimally Invasive Transforaminal Lumbar Interbody Fusion and Unilateral Fixation for Degenerative Lumbar Disease.

    Science.gov (United States)

    Wang, Hui-Wang; Hu, Yong-Cheng; Wu, Zhan-Yong; Wu, Hua-Rong; Wu, Chun-Fu; Zhang, Lian-Suo; Xu, Wei-Kun; Fan, Hui-Long; Cai, Jin-Sheng; Ma, Jian-Qing

    2017-08-01

    To evaluate the clinical effect of the minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation using a tubular retractor in the management of degenerative lumbar disease. A retrospective analysis was conducted to analyze the clinical outcome of 58 degenerative lumbar disease patients who were treated with minimally invasive transforaminal lumbar interbody fusion combined with posterolateral fusion and unilateral fixation during December 2012 to January 2015. The spine was unilaterally approached through a 3.0-cm skin incision centered on the disc space, located 2.5 cm lateral to the midline, and the multifidus muscles and longissimus dorsi were stripped off. After transforaminal lumbar interbody fusion and posterolateral fusion the unilateral pedicle screw fixation was performed. The visual analogue scale (VAS) for back and leg pain, the Oswestry disability index (ODI), and the MacNab score were applied to evaluate clinical effects. The operation time, peri-operative bleeding, postoperative time in bed, hospitalization costs, and the change in the intervertebral height were analyzed. Radiological fusion based on the Bridwell grading system was also assessed at the last follow-up. The quality of life of the patients before and after the operation was assessed using the short form-36 scale (SF-36). Fifty-eight operations were successfully performed, and no nerve root injury or dural tear occurred. The average operation time was 138 ± 33 min, intraoperative blood loss was 126 ± 50 mL, the duration from surgery to getting out of bed was 46 ± 8 h, and hospitalization cost was 1.6 ± 0.2 ten thousand yuan. All of the 58 patients were followed up for 7-31 months, with an average of 14.6 months. The postoperative VAS scores and ODI score were significantly improved compared with preoperative data (P degenerative lumbar disease, and the short-term clinical outcome is satisfactory

  9. Clinical outcome of trans-sacral interbody fusion after partial reduction for high-grade l5-s1 spondylolisthesis.

    Science.gov (United States)

    Smith, J A; Deviren, V; Berven, S; Kleinstueck, F; Bradford, D S

    2001-10-15

    A clinical retrospective study was conducted. To evaluate the clinical and radiographic outcome of reduction followed by trans-sacral interbody fusion for high-grade spondylolisthesis. In situ posterior interbody fusion with fibula allograft has improved the fusion rates for patients with high-grade spondylolisthesis. The use of this technique in conjunction with partial reduction has not been reported. Nine consecutive patients underwent treatment of high-grade (Grade 3 or 4) spondylolisthesis with partial reduction followed by posterior interbody fusion using cortical allograft. The average age at the time of surgery was 27 years (range, 8-51 years), and the average follow-up period was 43 months (range, 24-72 months). Before surgery, eight patients had low back pain, seven patients had radiating leg pain, and five patients had hamstring tightness. The average grade of spondylolisthesis by Meyerding grading was 3.9 (range, 3-5). Charts and radiographs were evaluated, and outcomes were collected by use of the modified SRS outcomes instrument. Radiographic indexes demonstrated significant improvement with partial reduction and fusion. The slip angle, as measured from the inferior endplate of L5, improved from 41.2 degrees (range, 24-82 degrees ) before surgery to 21 degrees (range, 5-40 degrees ) after surgery. All the patients were extremely or somewhat satisfied with surgery. The two patients who underwent this operation without initial instrumentation experienced fractures of their interbody grafts. Both of these patients underwent repair of the pseudarthrosis with placement of trans-sacral pedicle screw instrumentation and subsequent fusion. Partial reduction followed by posterior interbody fusion is an effective technique for the management of high-grade spondylolisthesis in pediatric and adult patient populations, as assessed by radiographic and clinical criteria. Pedicle screw instrumentation with the sacral screws capturing L5 is recommended when this

  10. Integrable peakon equations with cubic nonlinearity

    International Nuclear Information System (INIS)

    Hone, Andrew N W; Wang, J P

    2008-01-01

    We present a new integrable partial differential equation found by Vladimir Novikov. Like the Camassa-Holm and Degasperis-Procesi equations, this new equation admits peaked soliton (peakon) solutions, but it has nonlinear terms that are cubic, rather than quadratic. We give a matrix Lax pair for V Novikov's equation, and show how it is related by a reciprocal transformation to a negative flow in the Sawada-Kotera hierarchy. Infinitely many conserved quantities are found, as well as a bi-Hamiltonian structure. The latter is used to obtain the Hamiltonian form of the finite-dimensional system for the interaction of N peakons, and the two-body dynamics (N = 2) is explicitly integrated. Finally, all of this is compared with some analogous results for another cubic peakon equation derived by Zhijun Qiao. (fast track communication)

  11. AxiaLIF system: minimally invasive device for presacral lumbar interbody spinal fusion.

    Science.gov (United States)

    Rapp, Steven M; Miller, Larry E; Block, Jon E

    2011-01-01

    Lumbar fusion is commonly performed to alleviate chronic low back and leg pain secondary to disc degeneration, spondylolisthesis with or without concomitant lumbar spinal stenosis, or chronic lumbar instability. However, the risk of iatrogenic injury during traditional anterior, posterior, and transforaminal open fusion surgery is significant. The axial lumbar interbody fusion (AxiaLIF) system is a minimally invasive fusion device that accesses the lumbar (L4-S1) intervertebral disc spaces via a reproducible presacral approach that avoids critical neurovascular and musculoligamentous structures. Since the AxiaLIF system received marketing clearance from the US Food and Drug Administration in 2004, clinical studies of this device have reported high fusion rates without implant subsidence, significant improvements in pain and function, and low complication rates. This paper describes the design and approach of this lumbar fusion system, details the indications for use, and summarizes the clinical experience with the AxiaLIF system to date.

  12. Quasiparticle Interference on Cubic Perovskite Oxide Surfaces.

    Science.gov (United States)

    Okada, Yoshinori; Shiau, Shiue-Yuan; Chang, Tay-Rong; Chang, Guoqing; Kobayashi, Masaki; Shimizu, Ryota; Jeng, Horng-Tay; Shiraki, Susumu; Kumigashira, Hiroshi; Bansil, Arun; Lin, Hsin; Hitosugi, Taro

    2017-08-25

    We report the observation of coherent surface states on cubic perovskite oxide SrVO_{3}(001) thin films through spectroscopic-imaging scanning tunneling microscopy. A direct link between the observed quasiparticle interference patterns and the formation of a d_{xy}-derived surface state is supported by first-principles calculations. We show that the apical oxygens on the topmost VO_{2} plane play a critical role in controlling the coherent surface state via modulating orbital state.

  13. HRTEM studies of dislocations in cubic BN

    International Nuclear Information System (INIS)

    Nistor, L.C.; Tendeloo, G. van; Dinca, G.

    2004-01-01

    The atomic structure of dislocations in cubic boron nitride has been investigated by high resolution transmission electron microscopy. Most of the perfect dislocations, screw and 60 edge, are dissociated. A 60 dislocation which was undissociated has been analysed. Computer simulation is performed in an attempt to characterise the core structure. Twinning dislocations and dislocations resulting from the intersection of stacking faults are also revealed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. HRTEM studies of dislocations in cubic BN

    Energy Technology Data Exchange (ETDEWEB)

    Nistor, L.C. [National Institute for Materials Physics, P.O. Box MG-7 Magurele, 077125 Bucharest (Romania); Tendeloo, G. van [University of Antwerp, EMAT, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Dinca, G. [Dacia Synthetic Diamond Factory, Timisoara av. 5, P.O. Box 58-52, 077350 Bucharest (Romania)

    2004-09-01

    The atomic structure of dislocations in cubic boron nitride has been investigated by high resolution transmission electron microscopy. Most of the perfect dislocations, screw and 60 edge, are dissociated. A 60 dislocation which was undissociated has been analysed. Computer simulation is performed in an attempt to characterise the core structure. Twinning dislocations and dislocations resulting from the intersection of stacking faults are also revealed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Minimal knotted polygons in cubic lattices

    International Nuclear Information System (INIS)

    Van Rensburg, E J Janse; Rechnitzer, A

    2011-01-01

    In this paper we examine numerically the properties of minimal length knotted lattice polygons in the simple cubic, face-centered cubic, and body-centered cubic lattices by sieving minimal length polygons from a data stream of a Monte Carlo algorithm, implemented as described in Aragão de Carvalho and Caracciolo (1983 Phys. Rev. B 27 1635), Aragão de Carvalho et al (1983 Nucl. Phys. B 215 209) and Berg and Foester (1981 Phys. Lett. B 106 323). The entropy, mean writhe, and mean curvature of minimal length polygons are computed (in some cases exactly). While the minimal length and mean curvature are found to be lattice dependent, the mean writhe is found to be only weakly dependent on the lattice type. Comparison of our results to numerical results for the writhe obtained elsewhere (see Janse van Rensburg et al 1999 Contributed to Ideal Knots (Series on Knots and Everything vol 19) ed Stasiak, Katritch and Kauffman (Singapore: World Scientific), Portillo et al 2011 J. Phys. A: Math. Theor. 44 275004) shows that the mean writhe is also insensitive to the length of a knotted polygon. Thus, while these results for the mean writhe and mean absolute writhe at minimal length are not universal, our results demonstrate that these values are quite close the those of long polygons regardless of the underlying lattice and length

  16. Spondylectomy and lateral lumbar interbody fusion for thoracolumbar kyphosis in an adult with achondroplasia

    Science.gov (United States)

    Miyazaki, Masashi; Kanezaki, Shozo; Notani, Naoki; Ishihara, Toshinobu; Tsumura, Hiroshi

    2017-01-01

    Abstract Rationale: Fixed thoracolumbar kyphosis with spinal stenosis in adult patients with achondroplasia presents a challenging issue. We describe the first case in which spondylectomy and minimally invasive lateral access interbody arthrodesis were used for the treatment of fixed severe thoracolumbar kyphosis and lumbar spinal canal stenosis in an adult with achondroplasia. Patient concerns: A 61-year-old man with a history of achondroplastic dwarfism presented with low back pain and radiculopathy and neurogenic claudication. Diagnoses: Plain radiographs revealed a high-grade thoracolumbar kyphotic deformity with diffuse degenerative changes in the lumbar spine. The apex was located at L2, the local kyphotic angle from L1 to L3 was 105°, and the anterior area was fused from the L1 to L3 vertebrae. MRI revealed significant canal and lateral recess stenosis secondary to facet hypertrophy. Interventions: We planned a front-back correction of the anterior and posterior spinal elements. We first performed anterior release at the fused part from L1 to L3 and XLIF at L3/4 and L4/5. Next, the patient was placed in the prone position. Spondylectomy at the L2 vertebra and posterior fusion from T10 to L5 were performed. Postoperative radiographs revealed L1 to L3 kyphosis of 32°. Outcomes: No complications occurred during or after surgery. Postoperatively, the patient's low back pain and neurological claudication were resolved. No worsening of kyphosis was observed 24 months postoperatively. Lessons: Circumferential decompression of the spinal cord at the apical vertebral level and decompression of lumbar canal stenosis were necessary. Front-back correction of the anterior and posterior spinal elements via spondylectomy and lateral lumbar interbody fusion is a reasonable surgical option for thoracolumbar kyphosis and developmental canal stenosis in patients with achondroplasia. PMID:29245270

  17. Treatment of Spinal Tuberculosis by Debridement, Interbody Fusion and Internal Fixation via Posterior Approach Only.

    Science.gov (United States)

    Tang, Ming-xing; Zhang, Hong-qi; Wang, Yu-xiang; Guo, Chao-feng; Liu, Jin-yang

    2016-02-01

    Surgical treatment for spinal tuberculosis includes focal tuberculosis debridement, segmental stability reconstruction, neural decompression and kyphotic deformity correction. For the lesions mainly involved anterior and middle column of the spine, anterior operation of debridement and fusion with internal fixation has been becoming the most frequently used surgical technique for the spinal tuberculosis. However, high risk of structural damage might relate with anterior surgery, such as damage in lungs, heart, kidney, ureter and bowel, and the deformity correction is also limited. Due to the organs are in the front of spine, there are less complications in posterior approach. Spinal pedicle screw passes through the spinal three-column structure, which provides more powerful orthopedic forces compared with the vertebral body screw, and the kyphotic deformity correction effect is better in posterior approach. In this paper, we report a 68-year-old male patient with thoracic tuberculosis who underwent surgical treatment by debridement, interbody fusion and internal fixation via posterior approach only. The patient was placed in prone position under general anesthesia. Posterior midline incision was performed, and the posterior spinal construction was exposed. Then place pedicle screw, and fix one side rod temporarily. Make the side of more bone destruction and larger abscess as lesion debridement side. Resect the unilateral facet joint, and retain contralateral structure integrity. Protect the spinal cord, nerve root. Clear sequestrum, necrotic tissue, abscess of paravertebral and intervertebral space. Specially designed titanium mesh cages or bone blocks were implanted into interbody. Fix both side rods and compress both sides to make the mesh cages and bone blocks tight. Reconstruct posterior column structure with allogeneic bone and autologous bone. Using this technique, the procedures of debridement, spinal cord decompression, deformity correction, bone grafting

  18. Does Lordotic Angle of Cage Determine Lumbar Lordosis in Lumbar Interbody Fusion?

    Science.gov (United States)

    Hong, Taek-Ho; Cho, Kyu-Jung; Kim, Young-Tae; Park, Jae-Woo; Seo, Beom-Ho; Kim, Nak-Chul

    2017-07-01

    Retrospective, radiological analysis. To determine that 15° lordotic angle cages create higher lumbar lordosis in open transforaminal lumbar interbody fusion (TLIF) than 4° and 8° cages. Restoration of lumbar lordosis is important to obtain good outcome after lumbar fusion surgery. Various shapes and angles of cages in interbody fusion have been used; however, it is not proved that lordotic angle of cages determine lumbar lordosis. Sixty-seven patients were evaluated after TLIF using 15° cages and screw instrumentation. For comparison, TLIF using 4° lordotic angle cages in 65 patients and 8° cages in 49 patients were analyzed. Lumbar lordosis angles, segmental lordosis angles, disc height, and bony union rate were measured on the radiographs. The lumbar lordosis was 31.1° preoperatively, improved to 42.9° postoperatively, and decreased to 36.4° at the last follow-up in the 15° group. It was 35.8° before surgery, corrected to 41.5° after surgery, and changed to 33.6° at the last follow-up in the 4° group. In the 8° group, it was 32.7° preoperatively, improved to 39.1° postoperatively, and decreased to 34.5° at the last follow-up. These changes showed statistical significances (P lordosis at L4-5 was 6.6° before surgery, 13.1° after surgery, and 9.8° at the last follow-up in the 15° group. It was 6.9°, 9.5°, and 6.2° in the 4° group and 6.7°, 9.8°, and 8.1° in the 8° group, respectively (P lordosis after TLIF. Cages with sufficient lordotic angle showed better restoration of lumbar lordosis and prevention of loss of correction. 4.

  19. Comparison of Expandable and Fixed Interbody Cages in a Human Cadaver Corpectomy Model: Fatigue Characteristics.

    Science.gov (United States)

    Pekmezci, Murat; Tang, Jessica A; Cheng, Liu; Modak, Ashin; McClellan, Robert T; Buckley, Jenni M; Ames, Christopher P

    2016-11-01

    In vitro cadaver biomechanics study. The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs. Expandable cages are becoming more popular, in large part, due to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading. Nineteen specimens from 10 human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated after a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98 K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice. Three fixed and 2 expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in after initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage. Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared with fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages.

  20. Neutrosophic Cubic MCGDM Method Based on Similarity Measure

    Directory of Open Access Journals (Sweden)

    Surapati Pramanik

    2017-06-01

    Full Text Available The notion of neutrosophic cubic set is originated from the hybridization of the concept of neutrosophic set and interval valued neutrosophic set. We define similarity measure for neutrosophic cubic sets and prove some of its basic properties.

  1. Spinning solitons in cubic-quintic nonlinear media

    Indian Academy of Sciences (India)

    Spinning solitons in cubic-quintic nonlinear media ... features of families of bright vortex solitons (doughnuts, or 'spinning' solitons) in both conservative and dissipative cubic-quintic nonlinear media. ... Pramana – Journal of Physics | News.

  2. The effect of anterior longitudinal ligament resection on lordosis correction during minimally invasive lateral lumbar interbody fusion: Biomechanical and radiographic feasibility of an integrated spacer/plate interbody reconstruction device.

    Science.gov (United States)

    Kim, Choll; Harris, Jonathan A; Muzumdar, Aditya; Khalil, Saif; Sclafani, Joseph A; Raiszadeh, Kamshad; Bucklen, Brandon S

    2017-03-01

    Lateral lumbar interbody fusion is powerful for correcting degenerative conditions, yet sagittal correction remains limited by anterior longitudinal ligament tethering. Although lordosis has been restored via ligament release, biomechanical consequences remain unknown. Investigators examined radiographic and biomechanical of ligament release for restoration of lumbar lordosis. Six fresh-frozen human cadaveric spines (L3-S1) were tested: (Miller et al., 1988) intact; (Battie et al., 1995) 8mm spacer with intact anterior longitudinal ligament; (Cho et al., 2013) 8mm spacer without intact ligament following ligament resection; (Galbusera et al., 2013) 13mm lateral lumbar interbody fusion; (Goldstein et al., 2001) integrated 13mm spacer. Focal lordosis and range of motion were assessed by applying pure moments in flexion-extension, lateral bending, and axial rotation. Cadaveric radiographs showed significant improvement in lordosis correction following ligament resection (P0.05) but did little to restore lordosis. Ligament release significantly destabilized the spine relative to intact in all modes and 8mm with ligament in lateral bending and axial rotation (P0.05). Lordosis corrected by lateral lumbar interbody fusion can be improved by anterior longitudinal ligament resection, but significant construct instability and potential implant migration/dislodgment may result. This study shows that an added integrated lateral fixation system can significantly improve construct stability. Long-term multicenter studies are needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Anatomy of the psoas muscle and lumbar plexus with respect to the surgical approach for lateral transpsoas interbody fusion.

    Science.gov (United States)

    Kepler, Christopher K; Bogner, Eric A; Herzog, Richard J; Huang, Russel C

    2011-04-01

    Lateral transpsoas interbody fusion (LTIF) is a minimally invasive technique that permits interbody fusion utilizing cages placed via a direct lateral retroperitoneal approach. We sought to describe the locations of relevant neurovascular structures based on MRI with respect to this novel surgical approach. We retrospectively reviewed consecutive lumbosacral spine MRI scans in 43 skeletally mature adults. MRI scans were independently reviewed by two readers to identify the location of the psoas muscle, lumbar plexus, femoral nerve, inferior vena cava and right iliac vein. Structures potentially at risk for injury were identified by: a distance from the anterior aspect of the adjacent vertebral bodies of muscle and lumbar plexus is described which allows use of the psoas position as a proxy for lumbar plexus position to identify patients who may be at risk, particularly at the L4-5 level. Further study will establish the clinical relevance of these measurements and the ability of neurovascular structures to be retracted without significant injury.

  4. Minimally invasive presacral approach for revision of an Axial Lumbar Interbody Fusion rod due to fall-related lumbosacral instability: a case report

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    Cohen Anders

    2011-09-01

    Full Text Available Abstract Introduction The purpose of this study was to describe procedural details of a minimally invasive presacral approach for revision of an L5-S1 Axial Lumbar Interbody Fusion rod. Case presentation A 70-year-old Caucasian man presented to our facility with marked thoracolumbar scoliosis, osteoarthritic changes characterized by high-grade osteophytes, and significant intervertebral disc collapse and calcification. Our patient required crutches during ambulation and reported intractable axial and radicular pain. Multi-level reconstruction of L1-4 was accomplished with extreme lateral interbody fusion, although focal lumbosacral symptoms persisted due to disc space collapse at L5-S1. Lumbosacral interbody distraction and stabilization was achieved four weeks later with the Axial Lumbar Interbody Fusion System (TranS1 Inc., Wilmington, NC, USA and rod implantation via an axial presacral approach. Despite symptom resolution following this procedure, our patient suffered a fall six weeks postoperatively with direct sacral impaction resulting in symptom recurrence and loss of L5-S1 distraction. Following seven months of unsuccessful conservative care, a revision of the Axial Lumbar Interbody Fusion rod was performed that utilized the same presacral approach and used a larger diameter implant. Minimal adhesions were encountered upon presacral re-entry. A precise operative trajectory to the base of the previously implanted rod was achieved using fluoroscopic guidance. Surgical removal of the implant was successful with minimal bone resection required. A larger diameter Axial Lumbar Interbody Fusion rod was then implanted and joint distraction was re-established. The radicular symptoms resolved following revision surgery and our patient was ambulating without assistance on post-operative day one. No adverse events were reported. Conclusions The Axial Lumbar Interbody Fusion distraction rod may be revised and replaced with a larger diameter rod using

  5. Posterior Decompression, Lumber Interbody Fusion and Internal Fixation in the Treatment of Upper Lumbar Intervertebral Disc Herniation

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    DONG Zhan

    2014-12-01

    Full Text Available Objective: To assess the clinical outcomes of posterior decompression, interbody fusion and internal fixationfor the treatment of the upper lumbar intervertebral disc herniation. Methods: Twelve patients with the upper lumbar intervertebral disc herniation were treated by posterior decompression, interbosy fusion and internal fixation. The time of the operation, the amount of bleeding and the clinical efficacy were evaluated. Results: The time of operation was (143±36 min and the amount of bleeding during operation was (331.5±47.9 mL. There was no spinal cord and injuries, nerve injury, epidural damage and leakage of cerebrospinal fluid. All patients were followed up for 10~19 months with the average being 12.6 months. The functional scoring of Japanese Orthopedic Association (JOA before the operation was (11.4±3.3 scores and final score after follow-up was (22.9±3.1 scores and there were statistical difference (P<0.01. Lumber interbody fusion of all patients completed successfully and the good rate after the operation was 91.7%. Conclusion: Posterior decompression, interbody fusion and internal fixation for the treatment of the upper lumbar intervertebral disc herniation was characterized by full exposure, safety and significant efficacy.

  6. Visceral, vascular, and wound complications following over 13,000 lateral interbody fusions: a survey study and literature review.

    Science.gov (United States)

    Uribe, Juan S; Deukmedjian, Armen R

    2015-04-01

    Minimally invasive lateral interbody fusion (MIS-LIF) has become a popular less invasive treatment option for degenerative spinal disease, deformity, and trauma. While MIS-LIF offers several advantages over traditional anterior and posterior approaches, the procedure is not without risk. The purpose of this study was to evaluate the incidence of visceral, vascular, and wound complications following MIS-LIF performed by experienced surgeons. A survey was conducted by experienced (more than 100 case experience) MIS-LIF surgeons active in the society of lateral access surgery (SOLAS) to collect data on wound infections and visceral and vascular injuries. Of 77 spine surgeons surveyed, 40 (52 %) responded, including 25 (63 %) orthopedic surgeons and 15 (38 %) neurosurgeons, with 20 % practicing at an academic institution and 80 % in community practice. Between 2003 and 2013, 13,004 patients were treated with MIS-LIF by the 40 surgeons who responded to the survey. Of those patients, 0.08 % experienced a visceral complication (bowel injury), 0.10 % experienced a vascular injury, 0.27 % experienced a superficial wound infection, and 0.14 % experienced a deep wound infection. The incidence of surgical site infections and vascular and visceral complications following MIS-LIF in this large series was low and compared favorably with rates for alternative interbody fusion approaches. Although technically demanding, MIS-LIF is a reproducible approach for interbody fusion with a low risk of vascular and visceral complications and infections.

  7. Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices.

    Science.gov (United States)

    Torstrick, F Brennan; Klosterhoff, Brett S; Westerlund, L Erik; Foley, Kevin T; Gochuico, Joanna; Lee, Christopher S D; Gall, Ken; Safranski, David L

    2018-05-01

    Various surface modifications, often incorporating roughened or porous surfaces, have recently been introduced to enhance osseointegration of interbody fusion devices. However, these topographical features can be vulnerable to damage during clinical impaction. Despite the potential negative impact of surface damage on clinical outcomes, current testing standards do not replicate clinically relevant impaction loading conditions. The purpose of this study was to compare the impaction durability of conventional smooth polyether-ether-ketone (PEEK) cervical interbody fusion devices with two surface-modified PEEK devices that feature either a porous structure or plasma-sprayed titanium coating. A recently developed biomechanical test method was adapted to simulate clinically relevant impaction loading conditions during cervical interbody fusion procedures. Three cervical interbody fusion devices were used in this study: smooth PEEK, plasma-sprayed titanium-coated PEEK, and porous PEEK (n=6). Following Kienle et al., devices were impacted between two polyurethane blocks mimicking vertebral bodies under a constant 200 N preload. The posterior tip of the device was placed at the entrance between the polyurethane blocks, and a guided 1-lb weight was impacted upon the anterior face with a maximum speed of 2.6 m/s to represent the strike force of a surgical mallet. Impacts were repeated until the device was fully impacted. Porous PEEK durability was assessed using micro-computed tomography (µCT) pre- and postimpaction. Titanium-coating coverage pre- and postimpaction was assessed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. Changes to the surface roughness of smooth and titanium-coated devices were also evaluated. Porous PEEK and smooth PEEK devices showed minimal macroscopic signs of surface damage, whereas the titanium-coated devices exhibited substantial visible coating loss. Quantification of the porous PEEK deformation

  8. Surgical outcome of posterior lumbar interbody fusion with pedicle screw fixation for lumbar spondylolisthesis

    International Nuclear Information System (INIS)

    Shoda, Motoi; Kuno, Shigehiko; Inoue, Tatsushi

    2009-01-01

    Problems of lumbar spondylolisthesis treatment are many surgical tactics, elderly patient, osteoporosis, complications and recurrence of the symptoms. PLIF (posterior lumbar interbody fusion) and PS (pedicle screw) fixation technique for lumbar spondylolisthesis provide good patient satisfaction. Good outcome has been reported by only laminectomy alone, but patient satisfaction becomes worse year after year. The role of instrumentation for lumbar spondylolisthesis is decompression of the nerve root, correction of lumbar pathologies, bony fusion and early mobilization. We show our surgical technique and long term outcome of PLIF with PS for lumbar spondylolisthesis. Three hundred and fifty cases of lumbar spondylolisthesis were operated on in Department of Neurosurgery, Fujita Health University during the period of from December 1992 to August 2008. Patient background: age 16-84 years old (mean 62.5), Gender: male 153, female 197. Follow-up period 1-180 months (mean 61.2). Degenerative: 255, Isthmic: 63, Dysplastic: 10, Fracture: 5 and scoliosis 16 cases. Surgical procedure was PS with interbody fusion cage: 331, Hybrid cage (titanium cage with hydroxyapatite) 314, PS with Cerabone: 2 and PS with autograft: 17. CT was done to evaluate bony fusion postoperatively. Post operative improvements by JOA (Japan Orthopedic Association) score is 11.4 before surgery, 24.1 (post op. within 2 years), 25.4 (post op. 2-5 years), 25.0 (post op. 5-10 years) and 22.4 (post op. 10-15 years). Significant improvements were observed in %Slip and Slip angle but no remarkable change was observed in lumbar lordotic angle by postoperative X-ray evaluation. No root injury, and systemic complication except 4 cases of cerebrospinal fluid (CSF) leakage during surgery. Two cases were reoperated in whom cage with autograft migration due to pseudoarthrosis. Two cases had to undergo screw and cage system removal due to infection. Two cases of adjacent level stenosis had to undergo operation 10

  9. Black holes in a cubic Galileon universe

    Energy Technology Data Exchange (ETDEWEB)

    Babichev, E.; Charmousis, C.; Lehébel, A.; Moskalets, T., E-mail: eugeny.babichev@th.u-psud.fr, E-mail: christos.charmousis@th.u-psud.fr, E-mail: antoine.lehebel@th.u-psud.fr, E-mail: tetiana.moskalets@th.u-psud.fr [Laboratoire de Physique Théorique, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France)

    2016-09-01

    We find and study the properties of black hole solutions for a subclass of Horndeski theory including the cubic Galileon term. The theory under study has shift symmetry but not reflection symmetry for the scalar field. The Galileon is assumed to have linear time dependence characterized by a velocity parameter. We give analytic 3-dimensional solutions that are akin to the BTZ solutions but with a non-trivial scalar field that modifies the effective cosmological constant. We then study the 4-dimensional asymptotically flat and de Sitter solutions. The latter present three different branches according to their effective cosmological constant. For two of these branches, we find families of black hole solutions, parametrized by the velocity of the scalar field. These spherically symmetric solutions, obtained numerically, are different from GR solutions close to the black hole event horizon, while they have the same de-Sitter asymptotic behavior. The velocity parameter represents black hole primary hair.

  10. Cubic phase control of ultrashort laser pulses

    International Nuclear Information System (INIS)

    Mecseki, K.; Erdelyi, M.; Kovacs, A.P.; Szabo, G.

    2006-01-01

    Complete test of publication follows. The temporal shape of an ultrashort laser pulse may change upon propagating through a linear dispersive medium having a phase shift ψω. The change can be characterized by the Taylor-coefficients of the phase shift which are calculated around the central frequency ω 0 of the pulse. Measurements and independent control of the group delay dispersion (GDD, ψ'(ω 0 )) and the third order dispersion (TOD, ψ'(ω 0 )) are important in several research fields, particularly in the generation of ultrashort laser pulses by chirped pulse amplification (CPA) and pulse shaping for molecular control. The GDD and the TOD of an ideal pulse compressor are equal to the negative of the corresponding dispersion coefficients of the medium. However, in the case of prism-pair and grating-pair compressor is different from the ratio of the coefficients of the medium to be compensated for. Therefore it is necessary to develop so-called cubic compressors that are able to control the TOD of the pulse, yet, do not affect the GDD. In this paper a new cubic compressor setup is investigated theoretically and experimentally, which resembles the set-up proposed by White, however, we control the GDD and the TOD by the position of a birefringent, semi-cylinder crystal place around the focal point of an achromatic lens. For the evaluation of the phase shift introduced by the proposed cubic compressor, a ray tracing program was written. The program allows optimizing the compressor parameters, such as the radius of the crystal, magnification of the lens etc. Calcite was applied because it is a strong birefringent material. Calculations showed that there is a trajectory, along which shifting the crystal the TOD can be tuned independently of the GDD. The value of the TOD changed in a relatively wide range between -3.15 x 10 5 fs 3 and -1.67 x 10 5 fs 3 . Although the defocus also affects the angular dispersion of the pulse leaving the compressor, if does not exceed

  11. Cubic martensite in high carbon steel

    Science.gov (United States)

    Chen, Yulin; Xiao, Wenlong; Jiao, Kun; Ping, Dehai; Xu, Huibin; Zhao, Xinqing; Wang, Yunzhi

    2018-05-01

    A distinguished structural characteristic of martensite in Fe-C steels is its tetragonality originating from carbon atoms occupying only one set of the three available octahedral interstitial sites in the body-centered-cubic (bcc) Fe lattice. Such a body-centered-tetragonal (bct) structure is believed to be thermodynamically stable because of elastic interactions between the interstitial carbon atoms. For such phase stability, however, there has been a lack of direct experimental evidence despite extensive studies of phase transformations in steels over one century. In this Rapid Communication, we report that the martensite formed in a high carbon Fe-8Ni-1.26C (wt%) steel at room temperature induced by applied stress/strain has actually a bcc rather than a bct crystal structure. This finding not only challenges the existing theories on the stability of bcc vs bct martensite in high carbon steels, but also provides insights into the mechanism for martensitic transformation in ferrous alloys.

  12. Expansion into lattice harmonics in cubic symmetries

    Science.gov (United States)

    Kontrym-Sznajd, G.

    2018-05-01

    On the example of a few sets of sampling directions in the Brillouin zone, this work shows how important the choice of the cubic harmonics is on the quality of approximation of some quantities by a series of such harmonics. These studies led to the following questions: (1) In the case that for a given l there are several independent harmonics, can one use in the expansion only one harmonic with a given l?; (2) How should harmonics be ordered: according to l or, after writing them in terms of (x4 + y4 + z4)n (x2y2z2)m, according to their degree q = n + m? To enable practical applications of such harmonics, they are constructed in terms of the associated Legendre polynomials up to l = 26. It is shown that electron momentum densities, reconstructed from experimental data for ErGa3 and InGa3, are described much better by harmonics ordered with q.

  13. Clinico-radiological profile of indirect neural decompression using cage or auto graft as interbody construct in posterior lumbar interbody fusion in spondylolisthesis: Which is better?

    Directory of Open Access Journals (Sweden)

    Q R Abdul

    2011-01-01

    Full Text Available Study design: A prospective clinical study of posterior lumbar interbody fusion in grade I and II degenerative spondylolisthesis was conducted between Mar 2007 and Aug 2008. Purpose: The objective was to assess the clinicoradiological profile of structural v/s nonstructural graft on intervertebral disc height and its consequences on the low back pain (LBP assessed by Visual analog score (VAS score and oswestry disability index (ODI . This study involved 28 patients. Inclusion criteria: Age of 30-70 years, symptomatic patient with disturbed Activities of daily living (ADL, single-level L4/L5 or L5/S1 grade I or grade II degenerative spondylolisthesis. Exclusion criteria: Patients with osteoporosis, recent spondylodiscitis, subchondral sclerosis, visual and cognitive impairment and all other types of spondylolisthesis. All the patients underwent short-segment posterior fixation using CD2 or M8 instrumentation, laminectomy discectomy, reduction and distraction of the involved vertebral space. In 53.5% (n = 15 of the patients, snugly fitted local bone chips were used while in 46.4% (n = 13 of the patients, cage was used. Among the cage group, titanium cage was used in nine (32.1% and PEEK cages were used in four (14.2% patients. In one patient, a unilateral PEEK cage was used. The mean follow-up period was 24 months. Among the 28 patients, 67.8% (n = 19 were females and 32.14% (n = 9 were males. 68.24% (n = 18 had L4/L5 and 35.71% (n = 10 had L5/S1 spondylolisthesis. 39.28% (n = 11 were of grade I and 60.71% (n = 17 were of grade II spondylolisthesis. Conclusions: There was a statistically significant correlation (P < 0.012 and P < 0.027 between the change in disc height achieved and the improvement in VAS score in both the graft group and the cage group. The increment in disc height and VAS score was significantly better in the cage group (2 mm ± SD vis-a-vis 7.2 [88%] than the graft group (1.2 mm ± SD vis-a-vis 5 [62 %].

  14. Digitalized design of extraforaminal lumbar interbody fusion: a computer-based simulation and cadaveric study.

    Directory of Open Access Journals (Sweden)

    Mingjie Yang

    Full Text Available PURPOSE: This study aims to investigate the feasibility of a novel lumbar approach named extraforaminal lumbar interbody fusion (ELIF, a newly emerging minimally invasive technique for treating degenerative lumbar disorders, using a digitalized simulation and a cadaveric study. METHODS: The ELIF surgical procedure was simulated using the Mimics surgical simulator and included dissection of the superior articular process, dilation of the vertebral foramen, and placement of pedicle screws and a cage. ELIF anatomical measures were documented using a digitalized technique and subsequently validated on fresh cadavers. RESULTS: The use of the Mimics allowed for the vivid simulation of ELIF surgical procedures, while the cadaveric study proved the feasibility of this novel approach. ELIF had a relatively lateral access approach that was located 8-9 cm lateral to the median line with an access depth of approximately 9 cm through the intermuscular space. Dissection of the superior articular processes could fully expose the target intervertebral discs and facilitate a more inclined placement of the pedicle screws and cage with robust enhancement. CONCLUSIONS: According to the computer-based simulation and cadaveric study, it is feasible to perform ELIF. Further research including biomechanical study is needed to prove ELIF has a superior ability to preserve the posterior tension bands of the spinal column, with similar effects on spinal decompression, fixation, and fusion, and if it can enhance post-fusion spinal stability and expedites postoperative recovery.

  15. Digitalized design of extraforaminal lumbar interbody fusion: a computer-based simulation and cadaveric study.

    Science.gov (United States)

    Yang, Mingjie; Zeng, Cheng; Guo, Song; Pan, Jie; Han, Yingchao; Li, Zeqing; Li, Lijun; Tan, Jun

    2014-01-01

    This study aims to investigate the feasibility of a novel lumbar approach named extraforaminal lumbar interbody fusion (ELIF), a newly emerging minimally invasive technique for treating degenerative lumbar disorders, using a digitalized simulation and a cadaveric study. The ELIF surgical procedure was simulated using the Mimics surgical simulator and included dissection of the superior articular process, dilation of the vertebral foramen, and placement of pedicle screws and a cage. ELIF anatomical measures were documented using a digitalized technique and subsequently validated on fresh cadavers. The use of the Mimics allowed for the vivid simulation of ELIF surgical procedures, while the cadaveric study proved the feasibility of this novel approach. ELIF had a relatively lateral access approach that was located 8-9 cm lateral to the median line with an access depth of approximately 9 cm through the intermuscular space. Dissection of the superior articular processes could fully expose the target intervertebral discs and facilitate a more inclined placement of the pedicle screws and cage with robust enhancement. According to the computer-based simulation and cadaveric study, it is feasible to perform ELIF. Further research including biomechanical study is needed to prove ELIF has a superior ability to preserve the posterior tension bands of the spinal column, with similar effects on spinal decompression, fixation, and fusion, and if it can enhance post-fusion spinal stability and expedites postoperative recovery.

  16. Standard versus Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Prospective Randomized Study

    Directory of Open Access Journals (Sweden)

    Daniel Serban

    2017-01-01

    Full Text Available Symptomatic spondylolisthesis patients may benefit from surgical decompression and stabilization. The standard (S technique is a transforaminal lumbar interbody fusion (TLIF. Newer, minimally invasive (MI techniques seem to provide similar results with less morbidity. We enrolled patients with at least 6 months of symptoms and image-confirmed low-grade spondylolisthesis, at a single academic institution, between 2011 and 2015. The patients were randomized to either S or MI TLIF. The primary outcome measure was the Oswestry Disability Index (ODI improvement at 1 year. Secondary outcome measures included length of operation, estimated blood loss, length of hospitalization, and fusion rates at 1 year. Forty patients were enrolled in each group. The differences in mean operative time and estimated blood loss were not statistically significant between the two groups. The patients were discharged after surgery at 4.12 days for the S TLIF group and 1.92 days for the MI TLIF group. The ODI improvement was similar and statistically significant in both groups. The fusion was considered solid in 36 (90% of patients at 1 year in both groups. In conclusion, the two techniques provided similar clinical and radiological outcomes at 1 year. The patients undergoing MI TLIF had a shorter hospital stay. This trial is registered with NCT03155789.

  17. CORRECTION OF SEVERE STIFF SCOLIOSIS THROUGH EXTRAPLEURAL INTERBODY RELEASE AND OSTEOTOMY (LIEPO

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    Cleiton Dias Naves

    Full Text Available ABSTRACT Objective: To report a new technique for extrapleural interbody release with transcorporal osteotomy of the inferior vertebral plateau (LIEPO and to evaluate the correction potential of this technique and its complications. Method: We included patients with scoliosis with Cobb angle greater than 90° and flexibility less than 25% submitted to surgical treatment between 2012 and 2016 by the technique LIEPO at the National Institute of Traumatology and Orthopedics (INTO. Sagittal and coronal alignment, and the translation of the apical vertebra were measured and the degree of correction of the deformity was calculated through the pre and postoperative radiographs, and the complications were described. Results: Patients had an average bleed of 1,525 ml, 8.8 hours of surgical time, 123° of scoliosis in the preoperative period, and a mean correction of 66%. There was no case of permanent neurological damage and no surgical revision. Conclusion: The LIEPO technique proved to be effective and safe in the treatment of severe stiff scoliosis, reaching a correction potential close to the PEISR (Posterior extrapleural intervertebral space release technique and superior to that of the pVCR (posterior Vertebral Column Resection with no presence of infection and permanent neurological deficit. New studies are needed to validate this promising technique.

  18. AxiaLIF system: minimally invasive device for presacral lumbar interbody spinal fusion

    Directory of Open Access Journals (Sweden)

    Rapp SM

    2011-08-01

    Full Text Available Steven M Rapp1, Larry E Miller2,3, Jon E Block31Michigan Spine Institute, Waterford, MI, USA; 2Miller Scientific Consulting Inc, Biltmore Lake, NC, USA; 3Jon E. Block, Ph.D., Inc., San Francisco, CA, USAAbstract: Lumbar fusion is commonly performed to alleviate chronic low back and leg pain secondary to disc degeneration, spondylolisthesis with or without concomitant lumbar spinal stenosis, or chronic lumbar instability. However, the risk of iatrogenic injury during traditional anterior, posterior, and transforaminal open fusion surgery is significant. The axial lumbar interbody fusion (AxiaLIF system is a minimally invasive fusion device that accesses the lumbar (L4–S1 intervertebral disc spaces via a reproducible presacral approach that avoids critical neurovascular and musculoligamentous structures. Since the AxiaLIF system received marketing clearance from the US Food and Drug Administration in 2004, clinical studies of this device have reported high fusion rates without implant subsidence, significant improvements in pain and function, and low complication rates. This paper describes the design and approach of this lumbar fusion system, details the indications for use, and summarizes the clinical experience with the AxiaLIF system to date.Keywords: AxiaLIF, fusion, lumbar, minimally invasive, presacral

  19. Does prone repositioning before posterior fixation produce greater lordosis in lateral lumbar interbody fusion (LLIF)?

    Science.gov (United States)

    Yson, Sharon C; Sembrano, Jonathan N; Santos, Edward R G; Luna, Jeffrey T P; Polly, David W

    2014-10-01

    Retrospective comparative radiographic review. To determine if lateral to prone repositioning before posterior fixation confers additional operative level lordosis in lateral lumbar interbody fusion (LLIF) procedures. In a review of 56 consecutive patients who underwent LLIF, there was no statistically significant change in segmental lordosis from lateral to prone once a cage is in place. The greatest lordosis increase was observed after cage insertion. We reviewed 56 consecutive patients who underwent LLIF in the lateral position followed by posterior fixation in the prone position. Eighty-eight levels were fused. Disk space angle was measured on intraoperative C-arm images, and change in operative level segmental lordosis brought about by each of the following was determined: (1) cage insertion, (2) prone repositioning, and (3) posterior instrumentation. Paired t test was used to determine significance (α=0.05). Mean lordosis improvement brought about by cage insertion was 2.6 degrees (P=0.00005). There was a 0.1 degree mean lordosis change brought about by lateral to prone positioning (P=0.47). Mean lordosis improvement brought about by posterior fixation, including rod compression, was 1.0 degree (P=0.03). In LLIF procedures, the largest increase in operative level segmental lordosis is brought about by cage insertion. Further lordosis may be gained by placing posterior fixation, including compressive maneuvers. Prone repositioning after cage placement does not produce any incremental lordosis change. Therefore, posterior fixation may be performed in the lateral position without compromising operative level sagittal alignment.

  20. Clinical outcomes of two minimally invasive transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases.

    Science.gov (United States)

    Tian, Yonghao; Liu, Xinyu

    2016-10-01

    There are two modified TLIF, including MIS-TLIF and TLIF through Wiltse approach (W-TLIF). Although both of the two minimally invasive surgical procedures can be effective in the treatment for lumbar degenerative diseases, no comparative analysis has been made so far regarding their clinical outcomes. To compare the clinical outcomes of MIS-TLIF and W-TLIF for the treatment for single-segment degenerative lumbar diseases. Ninety-seven patients with single-segment degenerative lumbar disorders were included in this study. Forty-seven underwent MIS-TLIF surgery (group A). For group B, fifty patients underwent W-TLIF. The Japanese Orthopedic Association (JOA) score, the visual analog scale (VAS) of low back pain (LBP) and leg pain, MRI score and atrophy rate of CSA, interbody fusion rate were assessed during the postoperative follow-up. Incision length, blood loss, operative time, CPK, and postoperative incision pain VAS were better in group A (P degenerative disease. MIS-TLIF has less blood loss, shorter surgical incision, and less lower postoperative back pain, while W-TLIF is less expensive for hospital stay with lower exposure to X-rays.

  1. Accidental Durotomy in Minimally Invasive Transforaminal Lumbar Interbody Fusion: Frequency, Risk Factors, and Management

    Directory of Open Access Journals (Sweden)

    Jan-Helge Klingler

    2015-01-01

    Full Text Available Purpose. To assess the frequency, risk factors, and management of accidental durotomy in minimally invasive transforaminal lumbar interbody fusion (MIS TLIF. Methods. This single-center study retrospectively investigates 372 patients who underwent MIS TLIF and were mobilized within 24 hours after surgery. The frequency of accidental durotomies, intraoperative closure technique, body mass index, and history of previous surgery was recorded. Results. We identified 32 accidental durotomies in 514 MIS TLIF levels (6.2%. Analysis showed a statistically significant relation of accidental durotomies to overweight patients (body mass index ≥25 kg/m2; P=0.0493. Patient age older than 65 years tended to be a positive predictor for accidental durotomies (P=0.0657. Mobilizing patients on the first postoperative day, we observed no durotomy-associated complications. Conclusions. The frequency of accidental durotomies in MIS TLIF is low, with overweight being a risk factor for accidental durotomies. The minimally invasive approach seems to minimize durotomy-associated complications (CSF leakage, pseudomeningocele because of the limited dead space in the soft tissue. Patients with accidental durotomy can usually be mobilized within 24 hours after MIS TLIF without increased risk. The minimally invasive TLIF technique might thus be beneficial in the prevention of postoperative immobilization-associated complications such as venous thromboembolism. This trial is registered with DRKS00006135.

  2. Two-year Outcomes from a Single Surgeon's Learning Curve Experience of Oblique Lateral Interbody Fusion without Intraoperative Neuromonitoring.

    Science.gov (United States)

    Woods, Kamal; Fonseca, Ahtziri; Miller, Larry E

    2017-12-22

    Introduction Oblique lumbar interbody fusion (OLIF) is a newer procedure that avoids the psoas and lumbosacral plexus due to its oblique trajectory into the retroperitoneal space. While early experience with OLIF is reassuring, the longer-term clinical efficacy has not been well established. The purpose of this study was to describe two-year clinical outcomes with OLIF performed by a single surgeon during the learning curve without the aid of the neuromonitoring. Materials and methods Chart review was performed for the consecutive patients who underwent OLIF by a single surgeon. Back pain severity on a visual analog scale (VAS) and Oswestry Disability Index (ODI) were collected preoperatively and postoperatively at six weeks, three months, six months, one year and two years. Results A total of 21 patients (38 levels) were included in this study. The indications for surgery were degenerative disc disease (n=10, 47.6%), spondylolisthesis (n=9, 42.9%) and spinal stenosis (n=6, 28.6%). The median operating room time was 351 minutes (interquartile range (IQR): 279-406 minutes), blood loss was 40 ml (IQR: 30-150 ml), and hospital stay was 2.0 days (IQR: 1.0-3.5 days). The complication rate was 9.5%, both venous injuries. There were no other perioperative complications. Back pain severity decreased by 70%, on average, over two years (p safe and clinically efficacious for up to two years. The complication rate in this cohort is similar to other published OLIF series and appears acceptable when compared to the lateral lumbar interbody fusion (LLIF) and the anterior lumbar interbody fusion (ALIF). No motor or sensory deficits were observed in this study, supporting the premise that the neuromonitoring is unnecessary in OLIF.

  3. Biomechanics of lumbar cortical screw-rod fixation versus pedicle screw-rod fixation with and without interbody support.

    Science.gov (United States)

    Perez-Orribo, Luis; Kalb, Samuel; Reyes, Phillip M; Chang, Steve W; Crawford, Neil R

    2013-04-15

    Seven different combinations of posterior screw fixation, with or without interbody support, were compared in vitro using nondestructive flexibility tests. To study the biomechanical behavior of a new cortical screw (CS) fixation construct relative to the traditional pedicle screw (PS) construct. The CS is an alternative to the PS for posterior fixation of the lumbar spine. The CS trajectory is more sagittally and cranially oriented than the PS, being anchored in the pars interarticularis. Like PS fixation, CS fixation uses interconnecting rods fastened with top-locking connectors. Stability after bilateral CS fixation was compared with stability after bilateral PS fixation in the setting of intact disc and with direct lateral interbody fixation (DLIF) or transforaminal lateral interbody fixation (TLIF) support. Standard nondestructive flexibility tests were performed in cadaveric lumbar specimens, allowing non-paired comparisons of specific conditions from 28 specimens (4 groups of 7) within a larger experiment of multiple hardware configurations. Condition tested and group from which results originated were as follows: (1) intact (all groups); (2) with L3-L4 bilateral PS-rods (group 1); (3) with bilateral CS-rods (group 2); (4) with DLIF (group 3); (5) with DLIF + CS-rods (group 4); (6) with DLIF + PS-rods (group 3); (7) with TLIF + CS-rods (group 2), and (8) with TLIF + PS-rods (group 2). To assess spinal stability, the mean range of motion, lax zone, and stiff zone at L3-L4 were compared during flexion-extension, lateral bending, and axial rotation. With intact disc, stability was equivalent after PS-rod and CS-rod fixation, except that PS-rod fixation was stiffer during axial rotation. With DLIF support, there was no significant difference in stability between PS-rod and CS-rod fixation. With TLIF support, PS-rod fixation was stiffer than CS-rod fixation during lateral bending. Bilateral CS-rod fixation provided about the same stability in cadaveric specimens

  4. A STUDY OF POSTERIOR LUMBAR INTERBODY FUSION WITH LOCALLY HARVESTED SPINOLAMINECTOMY BONE GRAFT AND PEDICLE SCREW FIXATION IN SPONDYLOLISTHESIS

    Directory of Open Access Journals (Sweden)

    Pardhasaradhi M

    2017-08-01

    Full Text Available BACKGROUND Posterior Lumbar Interbody Fusion (PLIF and Transforaminal Lumbar Interbody Fusion (TLIF create intervertebral fusion by means of a posterior approach. Successful results have been reported with allograft, various cages (for interbody support, autograft and recombinant human bone morphogenetic protein‐2. Interbody fusion techniques facilitate reduction and enhance fusion. Corticocancellous laminectomy bone chips alone can be used as a means of spinal fusion in patients with single level instrumented PLIF. This has got a good fusion rate. PLIF with cage gives better fusion on radiology than PLIF with iliac bone graft, but no statistical difference in the clinical outcome. Cage use precludes complications associated with iliac bone harvesting. The reported adjacent segment degeneration was 40.5% and reoperation was 8.1% after 10 years of follow up. MATERIALS AND METHODS 30 cases of spondylolisthesis who attended the Orthopaedic Outpatient Department of Andhra Medical College, Visakhapatnam, from 2014 to 2016 were taken up for study. All the cases were examined clinically and confirmed radiologically. The patient’s age, sex, symptoms and duration were noted and were examined clinically for the status of the spine. Straight leg raising test was done and neurological examination of the lower limbs performed. All the patients were subjected to the radiological examination of the lumbosacral spine by taking anteroposterior, lateral (flexion and extension views, oblique views to demonstrate spondylolysis and spondylolisthesis. MRI and x-rays studies were done in all the cases to facilitate evaluation of the root compression disk changes and spinal cord changes. RESULTS In our study, we followed all the 30 patients after the surgery following procedure of removal of loose lamina, spinous process and fibrocartilaginous mass, PLIF with only the laminectomy bone mass and CD screw system fixation up to 2 years. 12 patients (40% had excellent

  5. Investigation of different cage designs and mechano-regulation algorithms in the lumbar interbody fusion process - a finite element analysis.

    Science.gov (United States)

    Postigo, Sergio; Schmidt, Hendrik; Rohlmann, Antonius; Putzier, Michael; Simón, Antonio; Duda, Georg; Checa, Sara

    2014-04-11

    Lumbar interbody fusion cages are commonly used to treat painful spinal degeneration and instability by achieving bony fusion. Many different cage designs exist, however the effect of cage morphology and material properties on the fusion process remains largely unknown. This finite element model study aims to investigate the influence of different cage designs on bone fusion using two mechano-regulation algorithms of tissue formation. It could be observed that different cages play a distinct key role in the mechanical conditions within the fusion region and therefore regulate the time course of the fusion process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Mesostructured germanium with cubic pore symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Armatas, G S; Kanatzidis, M G [Michigan State Univ., Michigan (United States), Dept. of Chemistry

    2006-11-15

    Regular mesoporous oxide materials have been widely studied and have a range of potential applications, such as catalysis, absorption and separation. They are not generally considered for their optical and electronic properties. Elemental semiconductors with nanopores running through them represent a different form of framework material with physical characteristics contrasting with those of the more conventional bulk, thin film and nanocrystalline forms. Here we describe cubic meso structured germanium, MSU-Ge-l, with gyroidal channels containing surfactant molecules, separated by amorphous walls that lie on the gyroid (G) minimal surface as in the mesoporous silica MCM-48. Although Ge is a high-meltin covalent semiconductor that is difficult to prepare from solution polymerization, we succeeded in assembling a continuous Ge network using a suitable precursor for Ge{sup 4-} atoms. Our results indicate that elemental semiconductors from group 14 of the periodic table can be made to adopt meso structured forms such as MSU-Ge-1, which features two three-dimensional labyrinthine tunnels obeying la3d space group symmetry and separated by a continuous germanium minimal surface that is otherwise amorphous. A consequence of this new structure for germanium, which has walls only one nanometre thick, is a wider electronic energy bandgap (1.4 eV versus 0.66 eV) than has crystalline or amorphous Ge. Controlled oxidation of MSU-Ge-1 creates a range of germanium suboxides with continuously varying Ge:O ratio and a smoothly increasing energy gap. (author)

  7. Topological Oxide Insulator in Cubic Perovskite Structure

    Science.gov (United States)

    Jin, Hosub; Rhim, Sonny H.; Im, Jino; Freeman, Arthur J.

    2013-01-01

    The emergence of topologically protected conducting states with the chiral spin texture is the most prominent feature at the surface of topological insulators. On the application side, large band gap and high resistivity to distinguish surface from bulk degrees of freedom should be guaranteed for the full usage of the surface states. Here, we suggest that the oxide cubic perovskite YBiO3, more than just an oxide, defines itself as a new three-dimensional topological insulator exhibiting both a large bulk band gap and a high resistivity. Based on first-principles calculations varying the spin-orbit coupling strength, the non-trivial band topology of YBiO3 is investigated, where the spin-orbit coupling of the Bi 6p orbital plays a crucial role. Taking the exquisite synthesis techniques in oxide electronics into account, YBiO3 can also be used to provide various interface configurations hosting exotic topological phenomena combined with other quantum phases. PMID:23575973

  8. Bifurcation of limit cycles for cubic reversible systems

    Directory of Open Access Journals (Sweden)

    Yi Shao

    2014-04-01

    Full Text Available This article is concerned with the bifurcation of limit cycles of a class of cubic reversible system having a center at the origin. We prove that this system has at least four limit cycles produced by the period annulus around the center under cubic perturbations

  9. Kinks in systems with cubic and quartic anharmonicity

    International Nuclear Information System (INIS)

    Kashcheev, V.N.

    1988-01-01

    For a classical system of interacting particles with on-site cubic or quartic anharmonicity explicit analytic solutions of the d'Alembert equation are obtained in the form of kinks in the presence of dissipation (viscous or Rayleigh) and a constant force. These kinks will be asymptotically stable in the case of quartic anharmonicity and unstable in the case cubic anharmonicity

  10. Characterization of a novel caudal vertebral interbody fusion in a rat tail model: An implication for future material and mechanical testing

    Directory of Open Access Journals (Sweden)

    Yu-Cheng Yeh

    2017-02-01

    Conclusion: The rat caudal disc interbody fusion model proved to be an efficient, repeatable and easily accessible model. Future research into adjuvant treatments like growth factor injection and alternative fusion materials under conditions of osteoporosis using this model would be worthwhile.

  11. Transforaminal lumbar interbody graft placement using an articulating delivery arm facilitates increased segmental lordosis with superior anterior and midline graft placement.

    Science.gov (United States)

    Shau, David N; Parker, Scott L; Mendenhall, Stephen K; Zuckerman, Scott L; Godil, Saniya S; Devin, Clinton J; McGirt, Matthew J

    2015-05-01

    Transforaminal lumbar interbody fusion (TLIF) is a frequently performed method of lumbar arthrodesis in patients failing medical management of back and leg pain. Accurate placement of the interbody graft and restoration of lordosis has been shown to be crucial when performing lumbar fusion procedures. We performed a single-surgeon, prospective, randomized study to determine whether a novel articulating versus traditional straight graft delivery arm system allows for superior graft placement and increased lordosis for single-level TLIF. Thirty consecutive patients undergoing single-level TLIF were included and prospectively randomized to one of the 2 groups (articulated vs. straight delivery arm system). Three radiographic characteristics were evaluated at 6-week follow-up: (1) degree of segmental lumbar lordosis at the fused level; (2) the percent anterior location of the interbody graft in disk space; and (3) the distance (mm) off midline of the interbody graft placement. Randomization yielded 16 patients in the articulated delivery arm cohort and 14 in the straight delivery arm cohort. The articulating delivery arm system yielded an average of 14.7-degree segmental lordosis at fused level, 35% anterior location, and 3.6 mm off midline. The straight delivery arm system yielded an average of 10.7-degree segmental lordosis at fused level, 46% anterior location, and 7.0 mm off midline. All 3 comparisons were statistically significant (Plordosis compared with a traditional straight delivery arm system.

  12. Extraforaminal Lumbar Interbody Fusion at the L5-S1 Level: Technical Considerations and Feasibility.

    Science.gov (United States)

    Kurzbuch, Arthur Robert; Kaech, Denis; Baranowski, Pawel; Baranowska, Alicja; Recoules-Arche, Didier

    2017-09-01

    Background  Extraforaminal lumbar interbody fusion (ELIF) surgery is a muscle-sparing approach that allows the treatment of various degenerative spinal diseases. It is technical challenging to perform the ELIF approach at the L5-S1 level because the sacral ala obstructs the view of the intervertebral disk space. Methods  We reported earlier on the ELIF technique in which the intervertebral disk is targeted at an angle of 45 degrees relative to the midline. In this article we describe the technical process we developed to overcome the anatomic relation between the sacral ala and the intervertebral disk space L5-S1 that hinders the ELIF approach at this level. We then report in a retrospective analysis on the short-term clinical and radiologic outcome of 100 consecutive patients with degenerative L5-S1 pathologies who underwent ELIF surgery. Results  The L5-S1 ELIF approach could be realized in all patients. The short-term clinical outcome was evaluated 5 months after surgery: 92% of the patients were satisfied with their postoperative result; 8% had a poor result. Overall, 17% of the patients presented light radicular or low back pain not influencing their daily activity, and 82% of the patients working before surgery returned to work 3 to 7 months after surgery. The radiologic outcome was documented by computed tomography at 5 months after surgery and showed fusion in 99% of the patients. Lumbar magnetic resonance imaging performed in 5 patients at 6 months after surgery revealed the integrity of the paraspinal muscles. Conclusions  ELIF surgery at the L5-S1 level is technically feasible for various degenerative spinal diseases. Analysis of the clinical and radiologic data in a consecutive retrospective cohort of patients who underwent this surgical procedure showed a good short-term clinical outcome and fusion rate. Georg Thieme Verlag KG Stuttgart · New York.

  13. Mast Quadrant-assisted Minimally Invasive Modified Transforaminal Lumbar Interbody Fusion: Single Incision Versus Double Incision

    Directory of Open Access Journals (Sweden)

    Xin-Lei Xia

    2015-01-01

    Full Text Available Background: The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion (TLIF with a small single posterior median incision. Methods: During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision (single incision group. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index (ODI scores, Visual Analog Scale (VAS scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results: A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group (P < 0.01. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups (P ≥ 0.05. Conclusions: Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.

  14. Uninstrumented Posterior Lumbar Interbody Fusion: Have Technological Advances in Stabilizing the Lumbar Spine Truly Improved Outcomes?

    Science.gov (United States)

    Prolo, Laura M; Oklund, Sally A; Zawadzki, Nadine; Desai, Manisha; Prolo, Donald J

    2018-04-06

    Since the 1980s, numerous operations have replaced posterior lumbar interbody fusion (PLIF) with human bone. These operations often involve expensive implants and complex procedures. Escalating expenditures in lumbar fusion surgery warrant re-evaluation of classical PLIF with allogeneic ilium and without instrumentation. The purpose of this study was to determine the long-term fusion rate and clinical outcomes of PLIF with allogeneic bone (allo-PLIF). Between 1981 and 2006, 321 patients aged 12-80 years underwent 339 1-level or 2-level allo-PLIFs for degenerative instability and were followed for 1-28 years. Fusion status was determined by radiographs and as available, by computed tomography scans. Clinical outcome was assessed by the Economic/Functional Outcome Scale. Of the 321 patients, 308 were followed postoperatively (average 6.7 years) and 297 (96%) fused. Fusion rates were lower for patients with substance abuse (89%, P = 0.007). Clinical outcomes in 87% of patients were excellent (52%) or good (35%). Economic/Functional Outcome Scale scores after initial allo-PLIF on average increased 5.2 points. Successful fusion correlated with nearly a 2-point gain in outcome score (P = 0.001). A positive association between a patient characteristic and outcome was observed only with age 65 years and greater, whereas negative associations in clinical outcomes were observed with mental illness, substance abuse, heavy stress to the low back, or industrial injuries. The total complication rate was 7%. With 3 decades of follow-up, we found that successful clinical outcomes are highly correlated with solid fusion using only allogeneic iliac bone. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Optical characterisation of cubic silicon carbide

    International Nuclear Information System (INIS)

    Jackson, S.M.

    1998-09-01

    The varied properties of Silicon Carbide (SiC) are helping to launch the material into many new applications, particularly in the field of novel semiconductor devices. In this work, the cubic form of SiC is of interest as a basis for developing integrated optical components. Here, the formation of a suitable SiO 2 buried cladding layer has been achieved by high dose oxygen ion implantation. This layer is necessary for the optical confinement of propagating light, and hence optical waveguide fabrication. Results have shown that optical propagation losses of the order of 20 dB/cm are obtainable. Much of this loss can be attributed to mode leakage and volume scattering. Mode leakage is a function of the effective oxide thickness, and volume scattering related to the surface layer damage. These parameters have been shown to be controllable and so suggests that further reduction in the waveguide loss is feasible. Analysis of the layer growth mechanism by RBS, XTEM and XPS proves that SiO 2 is formed, and that the extent, of formation depends on implant dose and temperature. The excess carbon generated is believed to exit the oxide layer by a number of varying mechanisms. The result of this appears to be a number of stable Si-C-O intermediaries that, form regions to either depth extreme of the SiO 2 layer. Early furnace tests suggest a need to anneal at, temperatures approaching the melting point of the silicon substrate, and that the quality of the virgin material is crucial in controlling the resulting oxide growth. (author)

  16. Neutron Dose Measurement Using a Cubic Moderator

    International Nuclear Information System (INIS)

    Sheinfeld, M.; Mazor, T.; Cohen, Y.; Kadmon, Y.; Orion, I.

    2014-01-01

    The Bonner Sphere Spectrometer (BSS), introduced In July 1960 by a research group from Rice University, Texas, is a major approach to neutron spectrum estimation. The BSS, also known as multi-sphere spectrometer, consists of a set of a different diameters polyethylene spheres, carrying a small LiI(Eu) scintillator in their center. What makes this spectrometry method such widely used, is its almost isotropic response, covering an extraordinary wide range of energies, from thermal up to even hundreds of MeVs. One of the most interesting and useful consequences of the above study is the 12'' sphere characteristics, as it turned out that the response curve of its energy dependence, have a similar shape compared with the neutron's dose equivalent as a function of energy. This inexplicable and happy circumstance makes it virtually the only monitoring device capable providing realistic neutron dose estimates over such a wide energy range. However, since the detection mechanism is not strictly related to radiation dose, one can expect substantial errors when applied to widely different source conditions. Although the original design of the BSS included a small 4mmx4mmO 6LiI(Eu) scintillator, other thermal neutron detectors has been used over the years: track detectors, activation foils, BF3 filled proportional counters, etc. In this study we chose a Boron loaded scintillator, EJ-254, as the thermal neutron detector. The neutron capture reaction on the boron has a Q value of 2.78 MeV of which 2.34 MeV is shared by the alpha and lithium particles. The high manufacturing costs, the encasement issue, the installation efficiency and the fabrication complexity, led us to the idea of replacing the sphere with a cubic moderator. This article describes the considerations, as well as the Monte-Carlo simulations done in order to examine the applicability of this idea

  17. Effects of Addition of Preoperative Intravenous Ibuprofen to Pregabalin on Postoperative Pain in Posterior Lumbar Interbody Fusion Surgery

    Directory of Open Access Journals (Sweden)

    Hüseyin Ulaş Pınar

    2017-01-01

    Full Text Available Objective. Ibuprofen and pregabalin both have independent positive effects on postoperative pain. The aim of the study is researching effect of 800 mg i.v. ibuprofen in addition to preoperative single dose pregabalin on postoperative analgesia and morphine consumption in posterior lumbar interbody fusion surgery. Materials and Methods. 42 adult ASA I-II physical status patients received 150 mg oral pregabalin 1 hour before surgery. Patients received either 250 ml saline with 800 mg i.v. ibuprofen or saline without ibuprofen 30 minutes prior to the surgery. Postoperative analgesia was obtained by morphine patient controlled analgesia (PCA and 1 g i.v. paracetamol every six hours. PCA morphine consumption was recorded and postoperative pain was evaluated by Visual Analog Scale (VAS in postoperative recovery room, at the 1st, 2nd, 4th, 8th, 12th, 24th, 36th, and 48th hours. Results. Postoperative pain was significantly lower in ibuprofen group in recovery room, at the 1st, 2nd, 36th, and 48th hours. Total morphine consumption was lower in ibuprofen group at the 2nd, 4th, 8th, 12th, and 48th hours. Conclusions. Multimodal analgesia with preoperative ibuprofen added to preoperative pregabalin safely decreases postoperative pain and total morphine consumption in patients having posterior lumbar interbody fusion surgery, without increasing incidences of bleeding or other side effects.

  18. Shape Preserving Interpolation Using C2 Rational Cubic Spline

    Directory of Open Access Journals (Sweden)

    Samsul Ariffin Abdul Karim

    2016-01-01

    Full Text Available This paper discusses the construction of new C2 rational cubic spline interpolant with cubic numerator and quadratic denominator. The idea has been extended to shape preserving interpolation for positive data using the constructed rational cubic spline interpolation. The rational cubic spline has three parameters αi, βi, and γi. The sufficient conditions for the positivity are derived on one parameter γi while the other two parameters αi and βi are free parameters that can be used to change the final shape of the resulting interpolating curves. This will enable the user to produce many varieties of the positive interpolating curves. Cubic spline interpolation with C2 continuity is not able to preserve the shape of the positive data. Notably our scheme is easy to use and does not require knots insertion and C2 continuity can be achieved by solving tridiagonal systems of linear equations for the unknown first derivatives di, i=1,…,n-1. Comparisons with existing schemes also have been done in detail. From all presented numerical results the new C2 rational cubic spline gives very smooth interpolating curves compared to some established rational cubic schemes. An error analysis when the function to be interpolated is ft∈C3t0,tn is also investigated in detail.

  19. On q-power cycles in cubic graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien

    2017-01-01

    In the context of a conjecture of Erdos and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e. with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic graphs with no q-power cycles. Concerning...... the remaining case q = 2 (which corresponds to the conjecture of Erdos and Gyárfás), we show that there exist arbitrarily large cubic graphs whose only 2-power cycles have length 4 only, or 8 only....

  20. Plastic fluctuations in empty crystals formed by cubic wireframe particles

    Science.gov (United States)

    McBride, John M.; Avendaño, Carlos

    2018-05-01

    We present a computer simulation study of the phase behavior of colloidal hard cubic frames, i.e., particles with nonconvex cubic wireframe geometry interacting purely by excluded volume. Despite the propensity of cubic wireframe particles to form cubic phases akin to their convex counterparts, these particles exhibit unusual plastic fluctuations in which a random and dynamic fraction of particles rotate around their lattice positions in the crystal lattice while the remainder of the particles remains fully ordered. We argue that this unexpected effect stems from the nonconvex geometry of the particles in which the faces of a particle can be penetrated by the vertices of the nearest neighbors even at high number densities.

  1. Bicontinuous cubic liquid crystalline nanoparticles for oral delivery of Doxorubicin

    DEFF Research Database (Denmark)

    Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog

    2014-01-01

    PURPOSE: The present study explores the potential of bicontinous cubic liquid crystalline nanoparticles (LCNPs) for improving therapeutic potential of doxorubicin. METHODS: Phytantriol based Dox-LCNPs were prepared using hydrotrope method, optimized for various formulation components, process...

  2. Do intraoperative radiographs predict final lumbar sagittal alignment following single-level transforaminal lumbar interbody fusion?

    Science.gov (United States)

    Salem, Khalid M I; Eranki, Aditya P; Paquette, Scott; Boyd, Michael; Street, John; Kwon, Brian K; Fisher, Charles G; Dvorak, Marcel F

    2018-05-01

    OBJECTIVE The study aimed to determine if the intraoperative segmental lordosis (as calculated on a cross-table lateral radiograph following a single-level transforaminal lumbar interbody fusion [TLIF] for degenerative spondylolisthesis/low-grade isthmic spondylolisthesis) is maintained at discharge and at 6 months postsurgery. METHODS The authors reviewed images and medical records of patients ≥ 16 years of age with a diagnosis of an isolated single-level, low-grade spondylolisthesis (degenerative or isthmic) with symptomatic spinal stenosis treated between January 2008 and April 2014. Age, sex, surgical level, surgical approach, and facetectomy (unilateral vs bilateral) were recorded. Upright standardized preoperative, early, and 6-month postoperative radiographs, as well as intraoperative lateral radiographs, were analyzed for the pelvic incidence, segmental lumbar lordosis (SLL) at the TILF level, and total LL (TLL). In addition, the anteroposterior position of the cage in the disc space was documented. Data are presented as the mean ± SD; a p value level using a bullet-shaped cage. A bilateral facetectomy was performed in 17 patients (20.2%), and 89.3% of procedures were done at the L4-5 and L5-S1 segments. SLL significantly improved intraoperatively from 15.8° ± 7.5° to 20.9° ± 7.7°, but the correction was lost after ambulation. Compared with preoperative values, at 6 months the change in SLL was modest at 1.8° ± 6.7° (p = 0.025), whereas TLL increased by 4.3° ± 9.6° (p level of surgery, and use of a bilateral facetectomy did not significantly affect postoperative LL. CONCLUSIONS Following a single-level TLIF procedure using a bullet-shaped cage, the intraoperative improvement in SLL is largely lost after ambulation. The improvement in TLL over time is probably due to the decompression part of the procedure. The approach, level of surgery, bilateral facetectomy, and position of the cage do not seem to have a significant effect on LL achieved

  3. Transforaminal lumbar interbody fusion versus posterolateral fusion in degenerative lumbar spondylosis

    Science.gov (United States)

    Zhang, Bin-Fei; Ge, Chao-Yuan; Zheng, Bo-Long; Hao, Ding-Jun

    2016-01-01

    Abstract Objective: The aim of the study was to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) versus posterolateral fusion (PLF) in degenerative lumbar spondylosis. Methods: A systematic literature review was performed to obtain randomized controlled trials (RCTs) and observational studies (OSs) of TLIF and PLF for degenerative lumbar spondylosis. Trials performed before November 2015 were retrieved from the Medline, EMBASE, Cochrane library, and Chinese databases. Data extraction and quality evaluation of the trials were performed independently by 2 investigators. A meta-analysis was performed using STATA version 12.0. Results: Two RCTs and 5 OSs of 630 patients were included. Of these subjects, 325 were in the TLIF and 305 were in the PLF group. Results showed that TLIF did not increase the fusion rate based on RCTs (relative risk [RR] = 1.06; 95% confidence interval [CI]: 0.95–1.18; P = 0.321), but increased it based on OSs (RR = 1.14; 95% CI: 1.07–1.23; P = 0.000) and overall (RR = 1.11; 95% CI: 1.05–1.18; P = 0.001) as compared with PLF. TLIF was able to improve the clinical outcomes based on 1 RCT (RR = 1.33; 95% CI: 1.11–1.59, P = 0.002) and overall (RR = 1.19; 95% CI: 1.07–1.33; P = 0.001), but not based on OSs (RR = 1.11; 95% CI: 0.97–1.27; P = 0.129) as compared with PLF. There were no differences between TLIF and PLF in terms of visual analogue scale, Oswestry Disability Index, reoperation, complications, duration of surgical procedure, blood loss, and hospitalization. Conclusions: In conclusion, evidence is not sufficient to support that TLIF provides higher fusion rate than PLF, and this poor evidence indicates that TLIF might improve only clinical outcomes. Higher quality, multicenter RCTs are needed to better define the role of TLIF and PLF. PMID:27749558

  4. Transforaminal lumbar interbody fusion versus posterolateral fusion in degenerative lumbar spondylosis: A meta-analysis.

    Science.gov (United States)

    Zhang, Bin-Fei; Ge, Chao-Yuan; Zheng, Bo-Long; Hao, Ding-Jun

    2016-10-01

    The aim of the study was to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) versus posterolateral fusion (PLF) in degenerative lumbar spondylosis. A systematic literature review was performed to obtain randomized controlled trials (RCTs) and observational studies (OSs) of TLIF and PLF for degenerative lumbar spondylosis. Trials performed before November 2015 were retrieved from the Medline, EMBASE, Cochrane library, and Chinese databases. Data extraction and quality evaluation of the trials were performed independently by 2 investigators. A meta-analysis was performed using STATA version 12.0. Two RCTs and 5 OSs of 630 patients were included. Of these subjects, 325 were in the TLIF and 305 were in the PLF group. Results showed that TLIF did not increase the fusion rate based on RCTs (relative risk [RR] = 1.06; 95% confidence interval [CI]: 0.95-1.18; P = 0.321), but increased it based on OSs (RR = 1.14; 95% CI: 1.07-1.23; P = 0.000) and overall (RR = 1.11; 95% CI: 1.05-1.18; P = 0.001) as compared with PLF. TLIF was able to improve the clinical outcomes based on 1 RCT (RR = 1.33; 95% CI: 1.11-1.59, P = 0.002) and overall (RR = 1.19; 95% CI: 1.07-1.33; P = 0.001), but not based on OSs (RR = 1.11; 95% CI: 0.97-1.27; P = 0.129) as compared with PLF. There were no differences between TLIF and PLF in terms of visual analogue scale, Oswestry Disability Index, reoperation, complications, duration of surgical procedure, blood loss, and hospitalization. In conclusion, evidence is not sufficient to support that TLIF provides higher fusion rate than PLF, and this poor evidence indicates that TLIF might improve only clinical outcomes. Higher quality, multicenter RCTs are needed to better define the role of TLIF and PLF.

  5. Combined posteroanterior fusion versus transforaminal lumbar interbody fusion (TLIF) in thoracolumbar burst fractures.

    Science.gov (United States)

    Schmid, Rene; Lindtner, Richard Andreas; Lill, Markus; Blauth, Michael; Krappinger, Dietmar; Kammerlander, Christian

    2012-04-01

    The optimal treatment strategy for burst fractures of the thoracolumbar junction is discussed controversially in the literature. Whilst 360° fusion has shown to result in better radiological outcome, recent studies have failed to show its superiority concerning clinical outcome. The morbidity associated with the additional anterior approach may account for these findings. The aim of this prospective observational study was therefore to compare two different techniques for 360° fusion in thoracolumbar burst fractures using either thoracoscopy or a transforaminal approach (transforaminal lumbar interbody fusion (TLIF)) to support the anterior column. Posterior reduction and short-segmental fixation using angular stable pedicle screw systems were performed in all patients as a first step. Monocortical strut grafts were used for the anterior support in the TLIF group, whilst tricortical grafts or titanium vertebral body replacing implants of adjustable height were used in the combined posteroanterior group. At final follow-up, the radiological outcome was assessed by performing X-rays in a standing position. The clinical outcome was measured using five validated outcome scores. The morbidity associated with the approaches and the donor site was assessed as well. There were 21 patients in the TLIF group and 14 patients in the posteroanterior group included. The postoperative loss of correction was higher in the TLIF group (4.9°±8.3° versus 3.4°±6.4°, p>0.05). There were no significant differences regarding the outcome scores between the two groups. There were no differences in terms of return to employment, leisure activities and back function either. More patients suffered from donor-site morbidity in the TLIF group, whilst the morbidity associated with the surgical approach was higher in the posteroanterior group. The smaller donor-site morbidity in the posteroanterior group is counterbalanced by an additional morbidity associated with the anterior approach

  6. Preliminary Experience with Anterior Interbody Titanium Cage Fusion for Treatment of Cervical Disc Disease

    Directory of Open Access Journals (Sweden)

    Chung-Nan Lin

    2003-05-01

    Full Text Available This study evaluated the efficacy and safety of titanium cage implants in cervical reconstruction to treat cervical spondylosis. Surgical data covered a 4-year period from January 1999 to December 2002 and included 34 consecutive patients, 20 men and 14 women, with ages ranging from 27 to 84 years (mean, 57 years. Patients underwent anterior cervical microdiscectomy followed by interbody fusion with a titanium cage implant (rather than an autogenous iliac crest bone graft at a single level ranging from C3 to C7. Twenty-one patients had a herniated intervertebral disc, nine had degenerative disc disease, and four had previous failed autograft fusion surgery that required revision. At clinical presentation, 26 patients had neck pain, 23 had radiculopathy, and nine had myelopathy. Diagnostic imaging studies included spinal dynamic roentgenography, computerized tomography, and magnetic resonance imaging. Lesions were located at C3-4 in seven cases, C4-5 in 14 cases, C5-6 in nine cases, and C6-7 in four cases. The follow-up period ranged from 7 to 48 months (mean, 26 months. Results revealed that the procedure was technically feasible. There were no intra- or postoperative complications. The most commonly used cage was 9 mm high. Imaging studies showed no cage instability, migration, or pseudarthrosis. Although mild subsidence (< 5 mm was observed in three cases, these patients preserved adequate postoperative cervical lordosis and the subsidence did not preclude a good clinical result. The advantages of this procedure over a similar operation using traditional tricorticate bone graft are: no graft morbidity; shorter operation time (mean time saved, 35 minutes; reduced blood loss (average blood loss, 75 mL; and early postoperative ambulation (mean, 4.7 hospital days. Nearly all patients rapidly lost their neck pain (92%, 24/26 and radicular symptoms (87%, 20/23 after surgery. The recovery rate from myelopathy was 44% (4/9. Progressive bony shield

  7. Evaluation of a novel tool for bone graft delivery in minimally invasive transforaminal lumbar interbody fusion

    Directory of Open Access Journals (Sweden)

    Kleiner JB

    2016-05-01

    Full Text Available Jeffrey B Kleiner, Hannah M Kleiner, E John Grimberg Jr, Stefanie J Throlson The Spine Center of Innovation, The Medical Center of Aurora, Aurora, CO, USA Study design: Disk material removed (DMR during L4-5 and L5-S1 transforaminal lumbar interbody fusion (T-LIF surgery was compared to the corresponding bone graft (BG volumes inserted at the time of fusion. A novel BG delivery tool (BGDT was used to apply the BG. In order to establish the percentage of DMR during T-LIF, it was compared to DMR during anterior diskectomy (AD. This study was performed prospectively. Summary of background data: Minimal information is available as to the volume of DMR during a T-LIF procedure, and the relationship between DMR and BG delivered is unknown. BG insertion has been empiric and technically challenging. Since the volume of BG applied to the prepared disk space likely impacts the probability of arthrodesis, an investigation is justified. Methods: A total of 65 patients with pathology at L4-5 and/or L5-S1 necessitating fusion were treated with a minimally invasive T-LIF procedure. DMR was volumetrically measured during disk space preparation. BG material consisting of local autograft, BG extender, and bone marrow aspirate were mixed to form a slurry. BG slurry was injected into the disk space using a novel BGDT and measured volumetrically. An additional 29 patients who were treated with L5-S1 AD were compared to L5-S1 T-LIF DMR to determine the percent of T-LIF DMR relative to AD. Results: DMR volumes averaged 3.6±2.2 mL. This represented 34% of the disk space relative to AD. The amount of BG delivered to the disk spaces was 9.3±3.2 mL, which is 2.6±2.2 times the amount of DMR. The BGDT allowed uncomplicated filling of the disk space in <1 minute. Conclusion: The volume of DMR during T-LIF allows for a predictable volume of BG delivery. The BGDT allowed complete filling of the entire prepared disk space. The T-LIF diskectomy debrides 34% of the disk

  8. Spinor bose gases in cubic optical lattice

    International Nuclear Information System (INIS)

    Mobarak, Mohamed Saidan Sayed Mohamed

    2014-01-01

    In recent years the quantum simulation of condensed-matter physics problems has resulted from exciting experimental progress in the realm of ultracold atoms and molecules in optical lattices. In this thesis we analyze theoretically a spinor Bose gas loaded into a three-dimensional cubic optical lattice. In order to account for different superfluid phases of spin-1 bosons with a linear Zeeman effect, we work out a Ginzburg-Landau theory for the underlying spin-1 Bose-Hubbard model. To this end we add artificial symmetry-breaking currents to the spin-1 Bose-Hubbard Hamiltonian in order to break the global U (1) symmetry. With this we determine a diagrammatic expansion of the grand-canonical free energy up to fourth order in the symmetry-breaking currents and up to the leading non-trivial order in the hopping strength which is of first order. As a cross-check we demonstrate that the resulting grand-canonical free energy allows to recover the mean-field theory. Applying a Legendre transformation to the grand-canonical free energy, where the symmetry-breaking currents are transformed to order parameters, we obtain the effective Ginzburg-Landau action. With this we calculate in detail at zero temperature the Mott insulator-superfluid quantum phase boundary as well as condensate and particle number density in the superfluid phase. We find that both mean-field and Ginzburg-Landau theory yield the same quantum phase transition between the Mott insulator and superfluid phases, but the range of validity of the mean-field theory turns out to be smaller than that of the Ginzburg-Landau theory. Due to this finding we expect that the Ginzburg-Landau theory gives better results for the superfluid phase and, thus, we restrict ourselves to extremize only the effective Ginzburg-Landau action with respect to the order parameters. Without external magnetic field the superfluid phase is a polar (ferromagnetic) state for anti-ferromagnetic (ferromagnetic) interactions, i.e. only the

  9. Nanodefects in ultrahard crystalline cubic boron nitride

    International Nuclear Information System (INIS)

    Nistor, S. V.; Stefan, M.; Goovaerts, E.; Schoemaker, D.

    2002-01-01

    Cubic boron nitride (cBN), the second hardest known material after diamond, exhibits high thermal conductivity and an excellent ability to be n or p doped, which makes it a strong candidate for the next generation of high-temperature micro optical and micro electronic devices. According to recent studies, cBN exhibits a better resistance to radiation damage than diamond, which suggests potential applications in extreme radiation environments. Crystalline cBN powders of up to 0.5 mm linear size is obtained in a similar way as diamond, by catalytic conversion of hexagonal BN (hBN) to cBN at even higher pressures (> 5GPa) and temperatures (∼ 1900 K). Considering the essential role played by the nanodefects (point defects and impurities) in determining its physical properties, it is surprising how limited is the amount of published data concerning the properties of nanodefects in this material, especially by Electron Paramagnetic Resonance (EPR) spectroscopy, the most powerful method for identification and characterization of nanodefects in both insulators and semiconductors. This seems to be due mainly to the absence of natural cBN gems and the extreme difficulties in producing even mm 3 sized synthetic crystals. We shall present our recent EPR studies on cBN crystalline powders, performed in a broad temperature range from room temperature (RT) down to 1.2 K on several sorts of large size cBN powder grits of yellow and amber color for industrial applications. Previous multifrequency (9.3 GHz and 95 GHz) EPR studies of brown to black cBN crystallites prepared with excess of boron, resulted in the discovery of two new types of paramagnetic point defects with different spectral properties, called the D1 and D2 centers. Our X(9.3 GHz)-band EPR investigations resulted in the observation in amber cBN crystalline powders of a spectrum with a strong temperature dependence of the lineshape. It was found that for high and low temperatures, respectively, the numerical

  10. The Combinatorial Rigidity Conjecture is False for Cubic Polynomials

    DEFF Research Database (Denmark)

    Henriksen, Christian

    2003-01-01

    We show that there exist two cubic polynomials with connected Julia sets which are combinatorially equivalent but not topologically conjugate on their Julia sets. This disproves a conjecture by McMullen from 1995.......We show that there exist two cubic polynomials with connected Julia sets which are combinatorially equivalent but not topologically conjugate on their Julia sets. This disproves a conjecture by McMullen from 1995....

  11. Interaction of dispersed cubic phases with blood components

    DEFF Research Database (Denmark)

    Bode, J C; Kuntsche, Judith; Funari, S S

    2013-01-01

    The interaction of aqueous nanoparticle dispersions, e.g. based on monoolein/poloxamer 407, with blood components is an important topic concerning especially the parenteral way of administration. Therefore, the influence of human and porcine plasma on dispersed cubic phases was investigated. Part...... activity of cubic phases based on monoolein and poloxamer 188, on soy phosphatidylcholine, glycerol dioleate and polysorbate 80 or the parenteral fat emulsion Lipofundin MCT 20%....

  12. MIS Single-position Lateral and Oblique Lateral Lumbar Interbody Fusion and Bilateral Pedicle Screw Fixation: Feasibility and Perioperative Results.

    Science.gov (United States)

    Blizzard, Daniel J; Thomas, J Alex

    2018-03-15

    Retrospective review of prospectively collected data of the first 72 consecutive patients treated with single-position one- or two-level lateral (LLIF) or oblique lateral interbody fusion (OLLIF) with bilateral percutaneous pedicle screw and rod fixation by a single spine surgeon. To evaluate the clinical feasibility, accuracy, and efficiency of a single-position technique for LLIF and OLLIF with bilateral pedicle screw and rod fixation. Minimally-invasive lateral interbody approaches are performed in the lateral decubitus position. Subsequent repositioning prone for bilateral pedicle screw and rod fixation requires significant time and resources and does not facilitate increased lumbar lordosis. The first 72 consecutive patients (300 screws) treated with single-position LLIF or OLLIF and bilateral pedicle screws by a single surgeon between December 2013 and August 2016 were included in the study. Screw accuracy and fusion were graded using computed tomography and several timing parameters were recorded including retractor, fluoroscopy, and screw placement time. Complications including reoperation, infection, and postoperative radicular pain and weakness were recorded. Average screw placement time was 5.9 min/screw (standard deviation, SD: 1.5 min; range: 3-9.5 min). Average total operative time (interbody cage and pedicle screw placement) was 87.9 minutes (SD: 25.1 min; range: 49-195 min). Average fluoroscopy time was 15.0 s/screw (SD: 4.7 s; range: 6-25 s). The pedicle screw breach rate was 5.1% with 10/13 breaches measured as < 2 mm in magnitude. Fusion rate at 6-months postoperative was 87.5%. Two (2.8%) patients underwent reoperation for malpositioned pedicle screws with subsequent resolution of symptoms. The single-position, all-lateral technique was found to be feasible with accuracy, fluoroscopy usage, and complication rates comparable with the published literature. This technique eliminates the time and staffing associated with

  13. Transdermal delivery of paeonol using cubic gel and microemulsion gel

    Science.gov (United States)

    Luo, Maofu; Shen, Qi; Chen, Jinjin

    2011-01-01

    Background The aim of this study was to develop new systems for transdermal delivery of paeonol, in particular microemulsion gel and cubic gel formulations. Methods Various microemulsion vehicles were prepared using isopropyl myristate as an oil phase, polyoxyethylated castor oil (Cremophor® EL) as a surfactant, and polyethylene glycol 400 as a cosurfactant. In the optimum microemulsion gel formulation, carbomer 940 was selected as the gel matrix, and consisted of 1% paeonol, 4% isopropyl myristate, 28% Cremophor EL/polyethylene glycol 400 (1:1), and 67% water. The cubic gel was prepared containing 3% paeonol, 30% water, and 67% glyceryl monooleate. Results A skin permeability test using excised rat skins indicated that both the cubic gel and microemulsion gel formulations had higher permeability than did the paeonol solution. An in vivo pharmacokinetic study done in rats showed that the relative bioavailability of the cubic gel and microemulsion gel was enhanced by about 1.51-fold and 1.28-fold, respectively, compared with orally administered paeonol suspension. Conclusion Both the cubic gel and microemulsion gel formulations are promising delivery systems to enhance the skin permeability of paeonol, in particular the cubic gel. PMID:21904450

  14. Comparison of serum markers for muscle damage, surgical blood loss, postoperative recovery, and surgical site pain after extreme lateral interbody fusion with percutaneous pedicle screws or traditional open posterior lumbar interbody fusion.

    Science.gov (United States)

    Ohba, Tetsuro; Ebata, Shigeto; Haro, Hirotaka

    2017-10-16

    The benefits of extreme lateral interbody fusion (XLIF) as a minimally invasive lumbar spinal fusion treatment for lumbar degenerative spondylolisthesis have been unclear. We sought to evaluate the invasiveness and tolerability of XLIF with percutaneous pedicle screws (PPS) compared with traditional open posterior lumbar interbody fusion (PLIF). Fifty-six consecutive patients underwent open PLIF and 46 consecutive patients underwent single-staged treatment with XLIF with posterior PPS fixation for degenerative lumbar spondylolisthesis, and were followed up for a minimum of 1 year. We analyzed postoperative serum makers for muscle damage and inflammation, postoperative surgical pain, and performance status. A Roland-Morris Disability Questionnaire (RDQ) and Oswestry Disability Index (ODI) were obtained at the time of hospital admission and 1 year after surgery. Intraoperative blood loss (51 ± 41 ml in the XLIF/PPS group and 206 ± 191 ml in the PLIF group), postoperative WBC counts and serum CRP levels in the XLIF/PPS group were significantly lower than in the PLIF group. Postoperative serum CK levels were significantly lower in the XLIF/PPS group on postoperative days 4 and 7. Postoperative recovery of performance was significantly greater in the XLIF/PPS group than in the PLIF group from postoperative days 2 to 7. ODI and visual analog scale (VAS) score (lumbar) 1 year after surgery were significantly lower in the XLIF/PPS group compared with the PLIF group. The XLIF/PPS procedure is advantageous to minimize blood loss and muscle damage, with consequent earlier recovery of daily activities and reduced incidence of low back pain after surgery than with the open PLIF procedure.

  15. Posterior lumbar interbody fusion (PLIF) with cages and local bone graft in the treatment of spinal stenosis.

    Science.gov (United States)

    Trouillier, Hans; Birkenmaier, Christof; Rauch, Alexander; Weiler, Christoph; Kauschke, Thomas; Refior, Hans Jürgen

    2006-08-01

    Posterior lumbar interbody fusion (PLIF) implants are increasingly being used for 360 degrees fusion after decompression of lumbar spinal stenosis combined with degenerative instability. Both titanium and PEEK (PolyEtherEtherKetone) implants are commonly used. Assessing the clinical and radiological results as well as typical complications, such as migration of the cages, is important. In addition, questions such as which radiological parameters can be used to assess successful fusion, and whether the exclusive use of local bone graft is sufficient, are frequently debated. We prospectively evaluated 30 patients after PLIF instrumentation for degenerative lumbar spinal canal stenosis, over a course of 42 months. In all cases, titanium cages and local bone graft were used for spondylodesis. The follow-up protocol of these 30 cases included standardised clinical and radiological evaluation at 3, 6, 12 and 42 months after surgery. Overall satisfactory results were achieved. With one exception, a stable result was achieved with restoration of the intervertebral space in the anterior column. After 42 months of follow-up in most cases, a radiologically visible loss of disc space height can be demonstrated. Clinically relevant migration of the cage in the dorsal direction was detected in one case. Based on our experience, posterior lumbar interbody fusion (PLIF) can be recommended for the treatment of monosegmental and bisegmental spinal stenosis, with or without segmental instability. Postoperative evaluation is mainly based on clinical parameters since the titanium implant affects the diagnostic value of imaging studies and is responsible for artefacts. The results observed in our group of patients suggest that local autologous bone graft procured from the posterior elements after decompression is an adequate material for bone grafting in this procedure.

  16. Spondylectomy and lateral lumbar interbody fusion for thoracolumbar kyphosis in an adult with achondroplasia: A case report.

    Science.gov (United States)

    Miyazaki, Masashi; Kanezaki, Shozo; Notani, Naoki; Ishihara, Toshinobu; Tsumura, Hiroshi

    2017-12-01

    Fixed thoracolumbar kyphosis with spinal stenosis in adult patients with achondroplasia presents a challenging issue. We describe the first case in which spondylectomy and minimally invasive lateral access interbody arthrodesis were used for the treatment of fixed severe thoracolumbar kyphosis and lumbar spinal canal stenosis in an adult with achondroplasia. A 61-year-old man with a history of achondroplastic dwarfism presented with low back pain and radiculopathy and neurogenic claudication. Plain radiographs revealed a high-grade thoracolumbar kyphotic deformity with diffuse degenerative changes in the lumbar spine. The apex was located at L2, the local kyphotic angle from L1 to L3 was 105°, and the anterior area was fused from the L1 to L3 vertebrae. MRI revealed significant canal and lateral recess stenosis secondary to facet hypertrophy. We planned a front-back correction of the anterior and posterior spinal elements. We first performed anterior release at the fused part from L1 to L3 and XLIF at L3/4 and L4/5. Next, the patient was placed in the prone position. Spondylectomy at the L2 vertebra and posterior fusion from T10 to L5 were performed. Postoperative radiographs revealed L1 to L3 kyphosis of 32°. No complications occurred during or after surgery. Postoperatively, the patient's low back pain and neurological claudication were resolved. No worsening of kyphosis was observed 24 months postoperatively. Circumferential decompression of the spinal cord at the apical vertebral level and decompression of lumbar canal stenosis were necessary. Front-back correction of the anterior and posterior spinal elements via spondylectomy and lateral lumbar interbody fusion is a reasonable surgical option for thoracolumbar kyphosis and developmental canal stenosis in patients with achondroplasia.

  17. Radiographic Results of Single Level Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spine Disease: Focusing on Changes of Segmental Lordosis in Fusion Segment

    OpenAIRE

    Kim, Sang-Bum; Jeon, Taek-Soo; Heo, Youn-Moo; Lee, Woo-Suk; Yi, Jin-Woong; Kim, Tae-Kyun; Hwang, Cheol-Mog

    2009-01-01

    Background To assess the radiographic results in patients who underwent transforaminal lumbar interbody fusion (TLIF), particularly the changes in segmental lordosis in the fusion segment, whole lumbar lordosis and disc height. Methods Twenty six cases of single-level TLIF in degenerative lumbar diseases were analyzed. The changes in segmental lordosis, whole lumbar lordosis, and disc height were evaluated before surgery, after surgery and at the final follow-up. Results The segmental lordosi...

  18. Preliminary results of anterior lumbar interbody fusion, anterior column realignment for the treatment of sagittal malalignment.

    Science.gov (United States)

    Hosseini, Pooria; Mundis, Gregory M; Eastlack, Robert K; Bagheri, Ramin; Vargas, Enrique; Tran, Stacie; Akbarnia, Behrooz A

    2017-12-01

    OBJECTIVE Sagittal malalignment decreases patients' quality of life and may require surgical correction to achieve realignment goals. High-risk posterior-based osteotomy techniques are the current standard treatment for addressing sagittal malalignment. More recently, anterior lumbar interbody fusion, anterior column realignment (ALIF ACR) has been introduced as an alternative for correction of sagittal deformity. The objective of this paper was to report clinical and radiographic results for patients treated using the ALIF-ACR technique. METHODS A retrospective study of 39 patients treated with ALIF ACR was performed. Patient demographics, operative details, radiographic parameters, neurological assessments, outcome measures, and preoperative, postoperative, and mean 1-year follow-up complications were studied. RESULTS The patient population comprised 39 patients (27 females and 12 males) with a mean follow-up of 13.3 ± 4.7 months, mean age of 66.1 ± 11.6 years, and mean body mass index of 27.3 ± 6.2 kg/m 2 . The mean number of ALIF levels treated was 1.5 ± 0.5. Thirty-three (84.6%) of 39 patients underwent posterior spinal fixation and 33 (84.6%) of 39 underwent posterior column osteotomy, of which 20 (60.6%) of 33 procedures were performed at the level of the ALIF ACR. Pelvic tilt, sacral slope, and pelvic incidence were not statistically significantly different between the preoperative and postoperative periods and between the preoperative and 1-year follow-up periods (except for PT between the preoperative and 1-year follow-up, p = 0.018). Sagittal vertical axis, T-1 spinopelvic inclination, lumbar lordosis, pelvic incidence-lumbar lordosis mismatch, intradiscal angle, and motion segment angle all improved from the preoperative to postoperative period and the preoperative to 1-year follow-up (p < 0.05). The changes in motion segment angle and intradiscal angle achieved in the ALIF-ACR group without osteotomy compared with the ALIF-ACR group with osteotomy

  19. 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.

  20. Can cantilever transforaminal lumbar interbody fusion (C-TLIF) maintain segmental lordosis for degenerative spondylolisthesis on a long-term basis?

    Science.gov (United States)

    Kida, Kazunobu; Tadokoro, Nobuaki; Kumon, Masashi; Ikeuchi, Masahiko; Kawazoe, Tateo; Tani, Toshikazu

    2014-03-01

    To determine if cantilever transforaminal lumbar interbody fusion (C-TLIF) using the crescent-shaped titanium interbody spacer (IBS) favors acquisition of segmental and lumbar lordosis even for degenerative spondylolisthesis (DS) on a long-term basis. We analyzed 23 consecutive patients who underwent C-TLIF with pedicle screw instrumentations fixed with compression for a single-level DS. Measurements on the lateral radiographs taken preoperatively, 2 weeks postoperatively and at final follow-up included disc angle (DA), segmental angle (SA), lumbar lordosis (LL), disc height (%DH) and slip rate (%slip). There was a good functional recovery with 100 % fusion rate at the mean follow-up of 62 months. Segmental lordosis (DA and SA) and %DH initially increased, but subsequently decreased with the subsidence of the interbody spacer, resulting in a significant increase (p = 0.046) only in SA from 13.2° ± 5.5° preoperatively to 14.7° ± 6.4° at the final follow-up. Changes of LL and %slip were more consistent without correction loss finally showing an increase of LL by 3.6° (p = 0.005) and a slip reduction by 6.7 % (p lordosis on a long-term basis, which would be of benefit in preventing hypolordosis-induced back pain and the adjacent level disc disease.

  1. [Multimodal medical image registration using cubic spline interpolation method].

    Science.gov (United States)

    He, Yuanlie; Tian, Lianfang; Chen, Ping; Wang, Lifei; Ye, Guangchun; Mao, Zongyuan

    2007-12-01

    Based on the characteristic of the PET-CT multimodal image series, a novel image registration and fusion method is proposed, in which the cubic spline interpolation method is applied to realize the interpolation of PET-CT image series, then registration is carried out by using mutual information algorithm and finally the improved principal component analysis method is used for the fusion of PET-CT multimodal images to enhance the visual effect of PET image, thus satisfied registration and fusion results are obtained. The cubic spline interpolation method is used for reconstruction to restore the missed information between image slices, which can compensate for the shortage of previous registration methods, improve the accuracy of the registration, and make the fused multimodal images more similar to the real image. Finally, the cubic spline interpolation method has been successfully applied in developing 3D-CRT (3D Conformal Radiation Therapy) system.

  2. Deformation of the cubic open string field theory

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Taejin, E-mail: taejin@kangwon.ac.kr

    2017-05-10

    We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings.

  3. Deformation of the cubic open string field theory

    Directory of Open Access Journals (Sweden)

    Taejin Lee

    2017-05-01

    Full Text Available We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings.

  4. Cubic interactions of Maxwell-like higher spins

    Energy Technology Data Exchange (ETDEWEB)

    Francia, Dario [Scuola Normale Superiore and INFN,Piazza dei Cavalieri, 7 I-56126 Pisa (Italy); Monaco, Gabriele Lo [Dipartimento di Fisica, Università di Pisa,Piazza Fibonacci, 3, I-56126, Pisa (Italy); Dipartimento di Fisica, Università di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Mkrtchyan, Karapet [Max Planck Institut für Gravitationsphysik,Am Mühlenberg 1, Potsdam 14476 (Germany)

    2017-04-12

    We study the cubic vertices for Maxwell-like higher-spins in flat and (A)dS background spaces of any dimension. Reducibility of their free spectra implies that a single cubic vertex involving any three fields subsumes a number of couplings among different particles of various spins. The resulting vertices do not involve traces of the fields and in this sense are simpler than their Fronsdal counterparts. We propose an extension of both the free theory and of its cubic deformation to a more general class of partially reducible systems, that one can obtain from the original theory upon imposing trace constraints of various orders. The key to our results is a version of the Noether procedure allowing to systematically account for the deformations of the transversality conditions to be imposed on the gauge parameters at the free level.

  5. Deformation of the cubic open string field theory

    International Nuclear Information System (INIS)

    Lee, Taejin

    2017-01-01

    We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings.

  6. Analysis and optimization of hybrid excitation permanent magnet synchronous generator for stand-alone power system

    Science.gov (United States)

    Wang, Huijun; Qu, Zheng; Tang, Shaofei; Pang, Mingqi; Zhang, Mingju

    2017-08-01

    In this paper, electromagnetic design and permanent magnet shape optimization for permanent magnet synchronous generator with hybrid excitation are investigated. Based on generator structure and principle, design outline is presented for obtaining high efficiency and low voltage fluctuation. In order to realize rapid design, equivalent magnetic circuits for permanent magnet and iron poles are developed. At the same time, finite element analysis is employed. Furthermore, by means of design of experiment (DOE) method, permanent magnet is optimized to reduce voltage waveform distortion. Finally, the validity of proposed design methods is validated by the analytical and experimental results.

  7. environmental/climatic effect on stand-alone solar energy supply

    African Journals Online (AJOL)

    This paper investigates the climatic effects and environmental variations on the perfor- mance of a ... inter-connected arrays due to shades from clouds, tress and ... Modeling of Solar Module .... needs. The earth revolves around the sun in an.

  8. Letting Go of Stand-Alone Technology: How to Blend Technology into Literacy Stations

    Science.gov (United States)

    Calvert, Heather

    2015-01-01

    With the nationwide focus on increasing students understanding and use of technology, many teachers are beginning to incorporate a variety of technology into small group rotations. However, the use of technology during these rotations often does not require students to use higher level thinking or problem solving skills. By eliminating the…

  9. Sizing and economic analysis of stand alone photovoltaic system with hydrogen storage

    Science.gov (United States)

    Nordin, N. D.; Rahman, H. A.

    2017-11-01

    This paper proposes a design steps in sizing of standalone photovoltaic system with hydrogen storage using intuitive method. The main advantage of this method is it uses a direct mathematical approach to find system’s size based on daily load consumption and average irradiation data. The keys of system design are to satisfy a pre-determined load requirement and maintain hydrogen storage’s state of charge during low solar irradiation period. To test the effectiveness of the proposed method, a case study is conducted using Kuala Lumpur’s generated meteorological data and rural area’s typical daily load profile of 2.215 kWh. In addition, an economic analysis is performed to appraise the proposed system feasibility. The finding shows that the levelized cost of energy for proposed system is RM 1.98 kWh. However, based on sizing results obtained using a published method with AGM battery as back-up supply, the system cost is lower and more economically viable. The feasibility of PV system with hydrogen storage can be improved if the efficiency of hydrogen storage technologies significantly increases in the future. Hence, a sensitivity analysis is performed to verify the effect of electrolyzer and fuel cell efficiencies towards levelized cost of energy. Efficiencies of electrolyzer and fuel cell available in current market are validated using laboratory’s experimental data. This finding is needed to envisage the applicability of photovoltaic system with hydrogen storage as a future power supply source in Malaysia.

  10. Optimal Sizing and Operation of Stand-Alone Hybrid Power Systems

    DEFF Research Database (Denmark)

    Kyriakidis, Ioannis; Chaudhary, Sanjay; Pillai, Jayakrishnan Radhakrishna

    2014-01-01

    for autonomous applications. Based on the island’s wind and solar potential, wind and solar systems appear as the most competitive solution while battery technologies provide the most feasible option for storing the excess energy. In the next, simulation models are developed in HOMER software. Various ratings...... of Renewable Energy Sources and Energy Storage Systems are considered and the most feasible combinations with respect to the Net Present Cost are calculated. The results have been assessed according to three scenarios, each of them representing a different policy and encountering several constraints....... Afterwards, steady-state analysis of the network is carried out considering typical cases of seasonal demand. The static model is developed in DIgSILENT PowerFactory software and the system’s behavior is investigated. In the following, the optimal placement for the wind, solar and storage units is discussed...

  11. Assessing Self-Regulation of Learning Dimensions in a Stand-alone MOOC Platform

    Directory of Open Access Journals (Sweden)

    Daniel Friday Owoichoche Onah

    2017-06-01

    Full Text Available A capacity for self-regulated learning (SRL has long been recognised as an important factor in successful studies. Although educational researchers have started to investigate the concept of SRL in the context of online education, very little is yet known about SRL in relation to massive open online courses (MOOCs or of appropriate strategies to foster SRL skills in MOOC learners. Self-regulation is particularly important in a MOOC-based study, which demands effective independent learning, and where widely acknowledged high dropout rates are observed. This study reports an investigation and assessment of the concept of SRL using a novel MOOC platform (eLDa by providing study options (either via a self-directed learning or instructor-led learning using a novel learning tool. In view of this, the research presents general description of self-regulated learning and explored the various existing dimensions used to expose the learners SRL skills. Drawing comparison of the online tool, the results and findings of the data were analysed. The study dis¬cusses how the various dimensions contributed to the knowledge representation of the self-regulated learning abilities shown by the learners. We present how these SRL dimensions captured using the measuring instrument contributes to our growing understanding of the distinctive features of the individual learner’s self-regulated learning. MOOCs success required a high performance of self-regulated learning abilities which at the moment very little has shown these degree of supporting SRL skills. This paper presents preliminary evaluation of a novel e-learning tool known, as ‘eLDa’ developed to implement this investi¬gation of self-regulation of learning. The research applied a modified online self-regulated learning questionnaire (OSLQ as the instrument to measure the SRL skills. The modified questionnaire known as MOOC OSLQ (MOSLQ was developed with a 19-item scale questions that exposes the six SRL dimensions used in this study.

  12. Perancangan Photovoltaic Stand Alone Sebagai Catu Daya Pada Base Transceiver Station Telekomunikasi Di Pulau Nusa Penida

    Directory of Open Access Journals (Sweden)

    I P Eka Indrawan

    2013-06-01

    Full Text Available Salah satu perangkat dalam jaringan komunikasi seluler adalah BTS (Base Transceiver Station. BTS yang ada di pulau Nusa Penida adalah BTS Nusa Penida dengan alamat desa kutampi dengan luas 500 m2. Sistem kelistrikan BTS  Nusa Penida dipasok oleh PLN dan genset,  dimana pada saat terjadi pemadaman energi listrik pada umumnya mempergunakan genset sebagai sumber energi listrik. Penggunaan genset mengakibatkan biaya operasional sangat tinggi, untuk itu diperlukan sumber lain yang lebih efisien. Besarnya potensi insolasi sinar harian matahari di Nusa penida, bisa sebagai  alternatif lain untuk sumber energi listrik dimana energi matahari bisa sebagai energi terbarukan untuk catu daya tambahan di BTS Nusa Penida yang pada akhirnya dapat menjaga  kestabilan suplai energi listrik ke BTS dan akses masyarakat terhadap informasi melalui seluler menjadi tidak terganggu. PV (Photovoltaic merupakan salah satu energi terbarukan yang dapat digunakan sebagai energi terbarukan untuk catu daya tambahan di BTS. Sistem PV yang dikembangkan untuk mensuplai energi listrik di BTS direncanakan sebesar 25%, adalah sistem PV yang hybrid dengan suplai listrik PLN. Besar daya PV yang dibangkitkan untuk mensuplai energi listrik di BTS adalah 9 kWp, yang dihasilkan dari panel PV sebanyak 45 panel dengan kapasitas panel PV adalah 200Wp dan kapasitas baterai yang akan digunakan adalah 3.800 Ah dengan total baterai 16. Analisis kelayakan investasi PV tanpa baterai dan PV dengan baterai yang dilakukan dengan menggunakan NPV, PI dan DPP menunjukkan hasil bahwa investasi PV layak untuk dilaksanakan. Untuk nilai NPV dan PI didapatkan kedua hasil investasi (> 0. Sedangkan untuk DPP didapatkan kedua hasil investasi dihasilkan lebih kecil dari periode umur proyek yang sudah ditetapkan, yaitu selama 25 tahun.

  13. Transforming stand-alone expert system into a community of cooperating agents

    CERN Document Server

    Jennings, N R; Aarnts, R P; Fuchs, J; Skarek, Paul

    1993-01-01

    Distributed Artificial Intelligence (DAI) systems in which multiple problem solving agents cooperate to achieve a common objective is a rapidly emerging and promising technology. However, as yet, there have been relatively few reported cases of such systems being employed to tackle real-world problems in realistic domains. One of the reasons for this is that DAI researchers have given virtually no consideration to the process of incorporating pre-existing systems into a community of cooperating agents. Yet reuse is a primary consideration for any organisation with a large software base. To redress the balance, this paper reports on an experiment undertaken at the CERN laboratories, in which two pre-existing and standalone expert systems for diagnosing faults in a particle accelerator were transformed into a community of cooperating agents. The experiences and insights gained during this process provide a valuable first step towards satisfying the needs of potential users of DAI technology - identifying the ty...

  14. New Scheme for Seamless Operation for Stand-Alone Power Systems

    Directory of Open Access Journals (Sweden)

    Hyun-Jun Kim

    2016-06-01

    Full Text Available On remote islands photovoltaic (PV panels with battery energy storage systems (BESSs supply electric power to customers in parallel operation with engine generators (EGs to reduce fuel consumption and environmental burden. A BESS operates in voltage control mode when it supplies power to loads alone, while it operates in current control mode when it supplies power to loads in parallel with the EG. This paper proposes a smooth mode change of the BESS from current control to voltage control by using initial value at the output of integral part in the voltage controller, and a smooth mode change from voltage control to current control by tracking the EG output voltage to the BESS output voltage using a phase-locked loop (PLL. The feasibility of the proposed scheme was verified through computer simulations and experiments with a scaled prototype.

  15. Feedforward control strategy for the state-decoupling Stand-alone UPS with LC output filter

    DEFF Research Database (Denmark)

    Lu, Jinghang; Savaghebi, Mehdi; Guerrero, Josep M.

    2017-01-01

    . In order to further increase the load current disturbance rejection capability of the state-decoupling in UPS system, a feedforward control strategy is proposed. In addition, the design principle for the current and voltage regulators are discussed. Simulation and experimental results are provided......In this paper, the disturbance rejection performance of the cascaded control strategy for UPS system is investigated. The comparison of closed loop system performance between conventional cascaded control (CCC) strategy and state-decoupling cascaded control (SDCC) strategy are further explored...

  16. APT - NASA ENHANCED VERSION OF AUTOMATICALLY PROGRAMMED TOOL SOFTWARE - STAND-ALONE VERSION

    Science.gov (United States)

    Premo, D. A.

    1994-01-01

    The APT code is one of the most widely used software tools for complex numerically controlled (N/C) machining. APT is an acronym for Automatically Programmed Tools and is used to denote both a language and the computer software that processes that language. Development of the APT language and software system was begun over twenty years ago as a U. S. government sponsored industry and university research effort. APT is a "problem oriented" language that was developed for the explicit purpose of aiding the N/C machine tools. Machine-tool instructions and geometry definitions are written in the APT language to constitute a "part program." The APT part program is processed by the APT software to produce a cutter location (CL) file. This CL file may then be processed by user supplied post processors to convert the CL data into a form suitable for a particular N/C machine tool. This June, 1989 offering of the APT system represents an adaptation, with enhancements, of the public domain version of APT IV/SSX8 to the DEC VAX-11/780 for use by the Engineering Services Division of the NASA Goddard Space Flight Center. Enhancements include the super pocket feature which allows concave and convex polygon shapes of up to 40 points including shapes that overlap, that leave islands of material within the pocket, and that have one or more arcs as part of the pocket boundary. Recent modifications to APT include a rework of the POCKET subroutine and correction of an error that prevented the use within a macro of a macro variable cutter move statement combined with macro variable double check surfaces. Former modifications included the expansion of array and buffer sizes to accommodate larger part programs, and the insertion of a few user friendly error messages. The APT system software on the DEC VAX-11/780 is organized into two separate programs: the load complex and the APT processor. The load complex handles the table initiation phase and is usually only run when changes to the APT processor capabilities are made. This phase initializes character recognition and syntax tables for the APT processor by creating FORTRAN block data programs. The APT processor consists of four components: the translator, the execution complex, the subroutine library, and the CL editor. The translator examines each APT statement in the part program for recognizable structure and generates a new statement, or series of statements, in an intermediate language. The execution complex processes all of the definition, motion, and related statements to generate cutter location coordinates. The subroutine library contains routines defining the algorithms required to process the sequenced list of intermediate language commands generated by the translator. The CL editor re-processes the cutter location coordinates according to user supplied commands to generate a final CL file. A sample post processor is also included which translates a CL file into a form for use with a Wales Strippit Fabramatic Model 30/30 sheet metal punch. The user should be able to readily develop post processors for other N/C machine tools. The APT language is a statement oriented, sequence dependent language. With the exception of such programming techniques as looping and macros, statements in an APT program are executed in a strict first-to-last sequence. In order to provide programming capability for the broadest possible range of parts and of machine tools, APT input (and output) is generalized, as represented by 3-dimensional geometry and tools, and arbitrarily uniform, as represented by the moving tool concept and output data in absolute coordinates. A command procedure allows the user to select the desired part program, ask for a graphics file of cutter motions in IGES format, and submit the procedure as a batch job, if desired. The APT system software is written in FORTRAN 77 for batch and interactive execution and has been implemented on a DEC VAX series computer under VMS 4.4. The enhancements for this version of APT were last updated in June, 1989. The NASA adaptation, with enhancements, of the public domain version of the APT IV/SSX8 software to the DEC VAX-11/780 is available by license for a period of ten (10) years to approved licensees. The licensed program product delivered includes the APT IV/SSX8 system source code, object code, executable images, and command procedures and one set of supporting documentation. Additional copies of the supporting documentation may be purchased at any time at the price indicated below.

  17. A high-performance stand-alone solar PV power system for LED lighting

    KAUST Repository

    Huang, B. J.

    2010-06-01

    The present study developed a high-performance solar PV power technology for the LED lighting of a solar home system. The nMPPO (near-Maximum-Power- Point- Operation) design is employed in system design to eliminate MPPT. A feedback control system using pulse width modulation (PWM) technique was developed for battery charging control which can increase the charging capacity by 78%. For high-efficiency lighting, the LED is directly driven by battery using a PWM discharge control to eliminate a DC/DC converter. Two solar-powered LED lighting systems (50W and 100W LED) were built. The long-term outdoor tests have shown that the loss of load probability for full-night lighting requirement is zero for 50W LED and 3.6% for 100W LED. © 2010 IEEE.

  18. Development of stand-alone risk assessment software for optimized maintenance planning of power plant facilities

    International Nuclear Information System (INIS)

    Choi, Woo Sung; Song, Gee Wook; Kim, Bum Shin; Chang, Sung Ho; Lee, Sang Min

    2015-01-01

    Risk-Risk-based inspection (RBI) has been developed in order to identify risky equipment that can cause major accidents or damages in large-scale plants. This assessment evaluates the equipment's risk, categorizes their priorities based on risk level, and then determines the urgency of their maintenance or allocates maintenance resources. An earlier version of the risk-based assessment software is already installed within the equipment management system; however, the assessment is based on examination by an inspector, and the results can be influenced by his subjective judgment, rather than assessment being based on failure probability. Moreover, the system is housed within a server, which limits the inspector's work space and time, and such a system can be used only on site. In this paper, the development of independent risk-based assessment software is introduced; this software calculates the failure probability by an analytical method, and analyzes the field inspection results, as well as inspection effectiveness. It can also operate on site, since it can be installed on an independent platform, and has the ability to generate an I/O function for the field inspection results regarding the period for an optimum maintenance cycle. This program will provide useful information not only to the field users who are participating in maintenance, but also to the engineers who need to decide whether to extend the life cycle of the power machinery or replace only specific components

  19. A high-performance stand-alone solar PV power system for LED lighting

    KAUST Repository

    Huang, B. J.; Hsu, P. C.; Wu, M. S.; Chen, K.Y.

    2010-01-01

    The present study developed a high-performance solar PV power technology for the LED lighting of a solar home system. The nMPPO (near-Maximum-Power- Point- Operation) design is employed in system design to eliminate MPPT. A feedback control system

  20. Last Stand-alone Beam Test of the Hadronic End-cap Calorimeter (HEC) Finished.

    CERN Multimedia

    Oberlack, H

    One quarter of all 134 HEC modules are tested with electron, pion and muon beams: two "partial HEC wheels", three HEC1 modules and three HEC2 modules, are used in a standard setup using the HEC cryostat in the H6 beam line. The picture shows a view of the set-up in the cryostat during the installation. MC results show that in this setup the energy leakage is well under control - well below 5 %. In addition, the other three quarters of modules are tested in technical cold tests. Using calibration signals, a detailed test of the cabling, cold electronics, crosstalk and noise performance is being done. The beam tests started with four prototype modules per run in '97, when technological optimization was still the key issue. From '98 onwards, modules of the "module 0" type have been tested, typically in two run periods per year. Finally in '99 the series production has started, with first beam test of series modules in 2000. Since then 57 series modules have been cold tested, 24 of them actually in beam tests. T...

  1. Wind-driven stand-alone DFIG with battery and pumped hydro ...

    Indian Academy of Sciences (India)

    Renewable energy electric conversion system; induction generators; wind power generation; energy storage; power converters. ... converter, (ii) wide speed operation of wind-driven DFIG, (iii) reduced battery capacity, (iv) high energy storage using PHSP and (v) availability of continuous power to the isolated loads.

  2. Stand-alone Cosmic Muon Reconstruction Before Installation of the CMS Silicon Strip Tracker

    CERN Document Server

    Adam, W.; Dragicevic, M.; Friedl, M.; Fruhwirth, R.; Hansel, S.; Hrubec, J.; Krammer, M.; Oberegger, M.; Pernicka, M.; Schmid, S.; Stark, R.; Steininger, H.; Uhl, D.; Waltenberger, W.; Widl, E.; Van Mechelen, P.; Cardaci, M.; Beaumont, W.; de Langhe, E.; de Wolf, E.A.; Delmeire, E.; Hashemi, M.; Bouhali, O.; Charaf, O.; Clerbaux, B.; Dewulf, J.-P.; Elgammal, S.; Hammad, G.; de Lentdecker, G.; Marage, P.; Vander Velde, C.; Vanlaer, P.; Wickens, J.; Adler, V.; Devroede, O.; De Weirdt, S.; D'Hondt, J.; Goorens, R.; Heyninck, J.; Maes, J.; Mozer, Matthias Ulrich; Tavernier, S.; Van Lancker, L.; Van Mulders, P.; Villella, I.; Wastiels, C.; Bonnet, J.-L.; Bruno, G.; De Callatay, B.; Florins, B.; Giammanco, A.; Gregoire, G.; Keutgen, Th.; Kcira, D.; Lemaitre, V.; Michotte, D.; Militaru, O.; Piotrzkowski, K.; Quertermont, L.; Roberfroid, V.; Rouby, X.; Teyssier, D.; Daubie, E.; Anttila, E.; Czellar, S.; Engstrom, P.; Harkonen, J.; Karimaki, V.; Kostesmaa, J.; Kuronen, A.; Lampen, T.; Linden, T.; Luukka, P.-R.; Maenpaa, T.; Michal, S.; Tuominen, E.; Tuominiemi, J.; Ageron, M.; Baulieu, G.; Bonnevaux, A.; Boudoul, G.; Chabanat, E.; Chabert, E.; Chierici, R.; Contardo, D.; Della Negra, R.; Dupasquier, T.; Gelin, G.; Giraud, N.; Guillot, G.; Estre, N.; Haroutunian, R.; Lumb, N.; Perries, S.; Schirra, F.; Trocme, B.; Vanzetto, S.; Agram, J.-L.; Blaes, R.; Drouhin, F.; Ernenwein, J.-P.; Fontaine, J.-C.; Berst, J.-D.; Brom, J.-M.; Didierjean, F.; Goerlach, U.; Graehling, P.; Gross, L.; Hosselet, J.; Juillot, P.; Lounis, A.; Maazouzi, C.; Olivetto, C.; Strub, R.; Van Hove, P.; Anagnostou, G.; Brauer, R.; Esser, H.; Feld, L.; Karpinski, W.; Klein, K.; Kukulies, C.; Olzem, J.; Ostapchuk, A.; Pandoulas, D.; Pierschel, G.; Raupach, F.; Schael, S.; Schwering, G.; Sprenger, D.; Thomas, M.; Weber, M.; Wittmer, B.; Wlochal, M.; Beissel, F.; Bock, E.; Flugge, G.; Gillissen, C.; Hermanns, T.; Heydhausen, D.; Jahn, D.; Kaussen, G.; Linn, A.; Perchalla, L.; Poettgens, M.; Pooth, O.; Stahl, A.; Zoeller, M.H.; Buhmann, P.; Butz, E.; Flucke, G.; Hamdorf, R.; Hauk, J.; Klanner, R.; Pein, U.; Schleper, P.; Steinbruck, G.; Blum, P.; De Boer, W.; Dierlamm, A.; Dirkes, G.; Fahrer, M.; Frey, M.; Furgeri, A.; Hartmann, F.; Heier, S.; Hoffmann, K.-H.; Kaminski, J.; Ledermann, B.; Liamsuwan, T.; Muller, S.; Muller, Th.; Schilling, F.-P.; Simonis, H.-J.; Steck, P.; Zhukov, V.; Cariola, P.; De Robertis, G.; Ferorelli, R.; Fiore, L.; Preda, M.; Sala, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Creanza, D.; De Filippis, N.; De Palma, M.; Giordano, D.; Maggi, G.; Manna, N.; My, S.; Selvaggi, G.; Albergo, S.; Chiorboli, M.; Costa, S.; Galanti, M.; Giudice, N.; Guardone, N.; Noto, F.; Potenza, R.; Saizu, M.A.; Sparti, V.; Sutera, C.; Tricomi, A.; Tuve, C.; Brianzi, M.; Civinini, C.; Maletta, F.; Manolescu, F.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Broccolo, B.; Ciulli, V.; D'Alessandro, R.; Focardi, E.; Frosali, S.; Genta, C.; Landi, G.; Lenzi, P.; Macchiolo, A.; Magini, N.; Parrini, G.; Scarlini, E.; Cerati, G.; Azzi, P.; Bacchetta, N.; Candelori, A.; Dorigo, T.; Kaminsky, A.; Karaevski, S.; Khomenkov, V.; Reznikov, S.; Tessaro, M.; Bisello, D.; De Mattia, M.; Giubilato, P.; Loreti, M.; Mattiazzo, S.; Nigro, M.; Paccagnella, A.; Pantano, D.; Pozzobon, N.; Tosi, M.; Bilei, G.M.; Checcucci, B.; Fano, L.; Servoli, L.; Ambroglini, F.; Babucci, E.; Benedetti, D.; Biasini, M.; Caponeri, B.; Covarelli, R.; Giorgi, M.; Lariccia, P.; Mantovani, G.; Marcantonini, M.; Postolache, V.; Santocchia, A.; Spiga, D.; Bagliesi, G.; Balestri, G.; Berretta, L.; Bianucci, S.; Boccali, T.; Bosi, F.; Bracci, F.; Castaldi, R.; Ceccanti, M.; Cecchi, R.; Cerri, C.; Cucoanes, A .S.; Dell'Orso, R.; Dobur, D.; Dutta, S.; Giassi, A.; Giusti, S.; Kartashov, D.; Kraan, A.; Lomtadze, T.; Lungu, G.A.; Magazzu, G.; Mammini, P.; Mariani, F.; Martinelli, G.; Moggi, A.; Palla, F.; Palmonari, F.; Petragnani, G.; Profeti, A.; Raffaelli, F.; Rizzi, D.; Sanguinetti, G.; Sarkar, S.; Sentenac, D.; Serban, A.T.; Slav, A.; Soldani, A.; Spagnolo, P.; Tenchini, R.; Tolaini, S.; Venturi, A.; Verdini, P.G.; Vos, M.; Zaccarelli, L.; Avanzini, C.; Basti, A.; Benucci, L.; Bocci, A.; Cazzola, U.; Fiori, F.; Linari, S.; Massa, M.; Messineo, A.; Segneri, G.; Tonelli, G.; Azzurri, P.; Bernardini, J.; Borrello, L.; Calzolari, F.; Foa, L.; Gennai, S.; Ligabue, F.; Petrucciani, G.; Rizzi, A.; Yang, Z.; Benotto, F.; Demaria, N.; Dumitrache, F.; Farano, R.; Borgia, M.A.; Castello, R.; Costa, M.; Migliore, E.; Romero, A.; Abbaneo, D.; Abbas, M.; Ahmed, I.; Akhtar, I.; Albert, E.; Bloch, C.; Breuker, H.; Butt, S.; Buchmuller, O.; Cattai, A.; Delaere, C.; Delattre, M.; Edera, L.M.; Engstrom, P.; Eppard, M.; Gateau, M.; Gill, K.; Giolo-Nicollerat, A.-S.; Grabit, R.; Honma, A.; Huhtinen, M.; Kloukinas, K.; Kortesmaa, J.; Kottelat, L.J.; Kuronen, A.; Leonardo, N.; Ljuslin, C.; Mannelli, M.; Masetti, L.; Marchioro, A.; Mersi, S.; Michal, S.; Mirabito, L.; Muffat-Joly, J.; Onnela, A.; Paillard, C.; Pal, I.; Pernot, J.F.; Petagna, P.; Petit, P.; Piccut, C.; Pioppi, M.; Postema, H.; Ranieri, R.; Ricci, D.; Rolandi, G.; Ronga, F.; Sigaud, C.; Syed, A.; Siegrist, P.; Tropea, P.; Troska, J.; Tsirou, A.; Vander Donckt, M.; Vasey, F.; Alagoz, E.; Amsler, Claude; Chiochia, V.; Regenfus, Christian; Robmann, P.; Rochet, J.; Rommerskirchen, T.; Schmidt, A.; Steiner, S.; Wilke, L.; Church, I.; Cole, J.; Coughlan, J.; Gay, A.; Taghavi, S.; Tomalin, I.; Bainbridge, R.; Cripps, N.; Fulcher, J.; Hall, G.; Noy, M.; Pesaresi, M.; Radicci, V.; Raymond, D.M.; Sharp, P.; Stoye, M.; Wingham, M.; Zorba, O.; Goitom, I.; Hobson, P.R.; Reid, I.; Teodorescu, L.; Hanson, G.; Jeng, G.-Y.; Liu, H.; Pasztor, G.; Satpathy, A.; Stringer, R.; Mangano, B.; Affolder, K.; Affolder, T.; Allen, A.; Barge, D.; Burke, S.; Callahan, D.; Campagnari, C.; Crook, A.; D'Alfonso, M.; Dietch, J.; Garberson, Jeffrey Ford; Hale, D.; Incandela, H.; Incandela, J.; Jaditz, S.; Kalavase, P.; Kreyer, S.; Kyre, S.; Lamb, J.; Mc Guinness, C.; Mills, C.; Nguyen, H.; Nikolic, M.; Lowette, S.; Rebassoo, F.; Ribnik, J.; Richman, J.; Rubinstein, N.; Sanhueza, S.; Shah, Y.; Simms, L.; Staszak, D.; Stoner, J.; Stuart, D.; Swain, S.; Vlimant, J.-R.; White, D.; Ulmer, K.A.; Wagner, S.R.; Bagby, L.; Bhat, P.C.; Burkett, K.; Cihangir, S.; Gutsche, O.; Jensen, H.; Johnson, M.; Luzhetskiy, N.; Mason, D.; Miao, T.; Moccia, S.; Noeding, C.; Ronzhin, A.; Skup, E.; Spalding, W.J.; Spiegel, L.; Tkaczyk, S.; Yumiceva, F.; Zatserklyaniy, A.; Zerev, E.; Anghel, I.; Bazterra, V.E.; Gerber, C.E.; Khalatian, S.; Shabalina, E.; Baringer, Philip S.; Bean, A.; Chen, J.; Hinchey, C.; Martin, C.; Moulik, T.; Robinson, R.; Gritsan, A.V.; Lae, C.K.; Tran, N.V.; Everaerts, P.; Hahn, K.A.; Harris, P.; Nahn, S.; Rudolph, M.; Sung, K.; Betchart, B.; Demina, R.; Gotra, Y.; Korjenevski, S.; Miner, D.; Orbaker, D.; Christofek, L.; Hooper, R.; Landsberg, G.; Nguyen, D.; Narain, M.; Speer, T.; Tsang, K.V.

    2009-01-01

    The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007. As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field. Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15% of the final silicon strip detector, and over 4.7 million events were recorded. This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses.

  3. Alignment of the CMS Silicon Strip Tracker during stand-alone Commissioning

    CERN Document Server

    Adam, W.; Dragicevic, M.; Friedl, M.; Fruhwirth, R.; Hansel, S.; Hrubec, J.; Krammer, M.; Oberegger, M.; Pernicka, M.; Schmid, S.; Stark, R.; Steininger, H.; Uhl, D.; Waltenberger, W.; Widl, E.; Van Mechelen, P.; Cardaci, M.; Beaumont, W.; de Langhe, E.; de Wolf, E.A.; Delmeire, E.; Hashemi, M.; Bouhali, O.; Charaf, O.; Clerbaux, B.; Dewulf, J.-P.; Elgammal, S.; Hammad, G.; de Lentdecker, G.; Marage, P.; Vander Velde, C.; Vanlaer, P.; Wickens, J.; Adler, V.; Devroede, O.; De Weirdt, S.; D'Hondt, J.; Goorens, R.; Heyninck, J.; Maes, J.; Mozer, Matthias Ulrich; Tavernier, S.; Van Lancker, L.; Van Mulders, P.; Villella, I.; Wastiels, C.; Bonnet, J.-L.; Bruno, G.; De Callatay, B.; Florins, B.; Giammanco, A.; Gregoire, G.; Keutgen, Th.; Kcira, D.; Lemaitre, V.; Michotte, D.; Militaru, O.; Piotrzkowski, K.; Quertermont, L.; Roberfroid, V.; Rouby, X.; Teyssier, D.; daubie, E.; Anttila, E.; Czellar, S.; Engstrom, P.; Harkonen, J.; Karimaki, V.; Kostesmaa, J.; Kuronen, A.; Lampen, T.; Linden, T.; Luukka, P.-R.; Maenaa, T.; Michal, S.; Tuominen, E.; Tuominiemi, J.; Ageron, M.; Baulieu, G.; Bonnevaux, A.; Boudoul, G.; Chabanat, E.; Chabert, E.; Chierici, R.; Contardo, D.; Della Negra, R.; Dupasquier, T.; Gelin, G.; Giraud, N.; Guillot, G.; Estre, N.; Haroutunian, R.; Lumb, N.; Perries, S.; Schirra, F.; Trocme, B.; Vanzetto, S.; Agram, J.-L.; Blaes, R.; Drouhin, F.; Ernenwein, J.-P.; Fontaine, J.-C.; Berst, J.-D.; Brom, J.-M.; Didierjean, F.; Goerlach, U.; Graehling, P.; Gross, L.; Hosselet, J.; Juillot, P.; Lounis, A.; Maazouzi, C.; Olivetto, C.; Strub, R.; Van Hove, P.; Anagnostou, G.; Brauer, R.; Esser, H.; Feld, L.; Karpinski, W.; Klein, K.; Kukulies, C.; Olzem, J.; Ostapchuk, A.; Pandoulas, D.; Pierschel, G.; Raupach, F.; Schael, S.; Schwering, G.; Sprenger, D.; Thomas, M.; Weber, M.; Wittmer, B.; Wlochal, M.; Beissel, F.; Bock, E.; Flugge, G.; Gillissen, C.; Hermanns, T.; Heydhausen, D.; Jahn, D.; Kaussen, G.; Linn, A.; Perchalla, L.; Poettgens, M.; Pooth, O.; Stahl, A.; Zoeller, M.H.; Buhmann, P.; Butz, E.; Flucke, G.; Hamdorf, R.; Hauk, J.; Klanner, R.; Pein, U.; Schleper, P.; Steinbruck, G.; Blum, P.; De Boer, W.; Dierlamm, A.; Dirkes, G.; Fahrer, M.; Frey, M.; Furgeri, A.; Hartmann, F.; Heier, S.; Hoffmann, K.-H.; Kaminski, J.; Ledermann, B.; Liamsuwan, T.; Muller, S.; Muller, Th.; Schilling, F.-P.; Simonis, H.-J.; Steck, P.; Zhukov, V.; Cariola, P.; De Robertis, G.; Ferorelli, R.; Fiore, L.; Preda, M.; Sala, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Creanza, D.; De Filippis, N.; De Palma, M.; Giordano, D.; Maggi, G.; Manna, N.; My, S.; Selvaggi, G.; Albergo, S.; Chiorboli, M.; Costa, S.; Galanti, M.; Giudice, N.; Guardone, N.; Noto, F.; Potenza, R.; Saizu, M.A.; Sparti, V.; Sutera, C.; Tricomi, A.; Tuve, C.; Brianzi, M.; Civinini, C.; Maletta, F.; Manolescu, F.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Broccolo, B.; Ciulli, V.; D'Alessandro, R.; Focardi, E.; Frosali, S.; Genta, C.; Landi, G.; Lenzi, P.; Macchiolo, A.; Magini, N.; Parrini, G.; Scarlini, E.; Cerati, G.; Azzi, P.; Bacchetta, N.; Candelori, A.; Dorigo, T.; Kaminsky, A.; Karaevski, S.; Khomenkov, V.; Reznikov, S.; Tessaro, M.; Bisello, D.; De Mattia, M.; Giubilato, P.; Loreti, M.; Mattiazzo, S.; Nigro, M.; Paccagnella, A.; Pantano, D.; Pozzobon, N.; Tosi, M.; Bilei, G.M.; Checcucci, B.; Fano, L.; Servoli, L.; Ambroglini, F.; Babucci, E.; Benedetti, D.; Biasini, M.; Caponeri, B.; Covarelli, R.; Giorgi, M.; Lariccia, P.; Mantovani, G.; Marcantonini, M.; Postolache, V.; Santocchia, A.; Spiga, D.; Bagliesi, G.; Balestri, G.; Berretta, L.; Bianucci, S.; Boccali, T.; Bosi, F.; Bracci, F.; Castaldi, R.; Ceccanti, M.; Cecchi, R.; Cerri, C.; Cucoanes, A.S.; Dell'Orso, R.; Dobur, D.; Dutta, S.; Giassi, A.; Giusti, S.; Kartashov, D.; Kraan, A.; Lomtadze, T.; Lungu, G.A.; Magazzu, G.; Mammini, P.; Mariani, F.; Martinelli, G.; Moggi, A.; Palla, F.; Palmonari, F.; Petragnani, G.; Profeti, A.; Raffaelli, F.; Rizzi, D.; Sanguinetti, G.; Sarkar, S.; Sentenac, D.; Serban, A.T.; Slav, A.; Soldani, A.; Spagnolo, P.; Tenchini, R.; Tolaini, S.; Venturi, A.; Verdini, P.G.; Vos, M.; Zaccarelli, L.; Avanzini, C.; Basti, A.; Benucci, L.; Bocci, A.; Cazzola, U.; Fiori, F.; Linari, S.; Massa, M.; Messineo, A.; Segneri, G.; Tonelli, G.; Azzurri, P.; Bernardini, J.; Borrello, L.; Calzolari, F.; Foa, L.; Gennai, S.; Ligabue, F.; Petrucciani, G.; Rizzi, A.; Yang, Z.; Benotto, F.; Demaria, N.; Dumitrache, F.; Farano, R.; Borgia, M.A.; Castello, R.; Costa, M.; Migliore, E.; Romero, A.; Abbaneo, D.; Abbas, M.; Ahmed, I.; Akhtar, I.; Albert, E.; Bloch, C.; Breuker, H.; Butt, S.; Buchmuller, O.; Cattai, A.; Delaere, C.; Delattre, M.; Edera, L.M.; Engstrom, P.; Eppard, M.; Gateau, M.; Gill, K.; Giolo-Nicollerat, A.-S.; Grabit, R.; Honma, A.; Huhtinen, M.; Kloukinas, K.; Kortesmaa, J.; Kottelat, L.J.; Kuronen, A.; Leonardo, N.; Ljuslin, C.; Mannelli, M.; Masetti, L.; Marchioro, A.; Mersi, S.; Michal, S.; Mirabito, L.; Muffat-Joly, J.; Onnela, A.; Paillard, C.; Pal, I.; Pernot, J.F.; Petagna, P.; Petit, P.; Piccut, C.; Pioppi, M.; Postema, H.; Ranieri, R.; Ricci, D.; Rolandi, G.; Ronga, F.; Sigaud, C.; Syed, A.; Siegrist, P.; Tropea, P.; Troska, J.; Tsirou, A.; Vander Donckt, M.; Vasey, F.; Alagoz, E.; Amsler, Claude; Chiochia, V.; Regenfus, Christian; Robmann, P.; Rochet, J.; Rommerskirchen, T.; Schmidt, A.; Steiner, S.; Wilke, L.; Church, I.; Cole, J.; Coughlan, J.; Gay, A.; Taghavi, S.; Tomalin, I.; Bainbridge, R.; Cripps, N.; Fulcher, J.; Hall, G.; Noy, M.; Pesaresi, M.; Radicci, V.; Raymond, D.M.; Sharp, P.; Stoye, M.; Wingham, M.; Zorba, O.; Goitom, I.; Hobson, P.R.; Reid, I.; Teodorescu, L.; Hanson, G.; Jeng, G.-Y.; Liu, H.; Pasztor, G.; Satpathy, A.; Stringer, R.; Mangano, B.; Affolder, K.; Affolder, T.; Allen, A.; Barge, D.; Burke, S.; Callahan, D.; Campagnari, C.; Crook, A.; D'Alfonso, M.; Dietch, J.; Garberson, Jeffrey Ford; Hale, D.; Incandela, H.; Incandela, J.; Jaditz, S.; Kalavase, P.; Kreyer, S.; Kyre, S.; Lamb, J.; Mc Guinnessr, C.; Mills, C.; Nguyen, H.; Nikolic, M.; Lowette, S.; Rebassoo, F.; Ribnik, J.; Richman, J.; Rubinstein, N.; Sanhueza, S.; Shah, Y.; Simms, L.; Staszak, D.; Stoner, J.; Stuart, D.; Swain, S.; Vlimant, J.-R.; White, D.; Ulmer, K.A.; Wagner, S.R.; Bagby, L.; Bhat, P.C.; Burkett, K.; Cihangir, S.; Gutsche, O.; Jensen, H.; Johnson, M.; Luzhetskiy, N.; Mason, D.; Miao, T.; Moccia, S.; Noeding, C.; Ronzhin, A.; Skup, E.; Spalding, W.J.; Spiegel, L.; Tkaczyk, S.; Yumiceva, F.; Zatserklyaniy, A.; Zerev, E.; Anghel, I.; Bazterra, V.E.; Gerber, C.E.; Khalatian, S.; Shabalina, E.; Baringer, Philip S.; Bean, A.; Chen, J.; Hinchey, C.; Martin, C.; Moulik, T.; Robinson, R.; Gritsan, A.V.; Lae, C.K.; Tran, N.V.; Everaerts, P.; Hahn, K.A.; Harris, P.; Nahn, S.; Rudolph, M.; Sung, K.; Betchart, B.; Demina, R.; Gotra, Y.; Korjenevski, S.; Miner, D.; Orbaker, D.; Christofek, L.; Hooper, R.; Landsberg, G.; Nguyen, D.; Narain, M.; Speer, T.; Tsang, K.V.

    2009-01-01

    The results of the CMS tracker alignment analysis are presented using the data from cosmic tracks, optical survey information, and the laser alignment system at the Tracker Integration Facility at CERN. During several months of operation in the spring and summer of 2007, about five million cosmic track events were collected with a partially active CMS Tracker. This allowed us to perform first alignment of the active silicon modules with the cosmic tracks using three different statistical approaches; validate the survey and laser alignment system performance; and test the stability of Tracker structures under various stresses and temperatures ranging from +15C to -15C. Comparison with simulation shows that the achieved alignment precision in the barrel part of the tracker leads to residual distributions similar to those obtained with a random misalignment of 50 (80) microns in the outer (inner) part of the barrel.

  4. Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners.

    Science.gov (United States)

    Batterman, S; Du, L; Mentz, G; Mukherjee, B; Parker, E; Godwin, C; Chin, J-Y; O'Toole, A; Robins, T; Rowe, Z; Lewis, T

    2012-06-01

    This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84±27%, but dropped to 63±33% in subsequent seasons. In months when households were not visited, use averaged only 34±30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions. Environmental tobacco smoke (ETS) increased particulate matter (PM) levels by about 14 μg/m3 and was often detected using ETS-specific tracers despite restrictions on smoking in the house as reported on questionnaires administered to caregivers. PM concentrations depended on season, filter usage, relative humidity, air exchange ratios, number of children, outdoor PM levels, sweeping/dusting, and presence of a central air conditioner (AC). Free-standing air filters can be an effective intervention that provides substantial reductions in PM concentrations if the filters are used. However, filter use was variable across the study population and declined over the study duration, and thus strategies are needed to encourage and maintain use of filters. The variability in filter use suggests that exposure misclassification is a potential problem in intervention studies using filters. The installation of a room AC in the bedroom, intended to limit air exchange ratios, along with an air filter, did not lower PM levels more than the filter alone. © 2011 John Wiley & Sons A/S.

  5. A Voltage and Frequency Control Strategy for Stand-Alone Full Converter Wind Energy Conversion Systems

    Directory of Open Access Journals (Sweden)

    Andrés Peña Asensio

    2018-02-01

    Full Text Available This paper addresses the design and analysis of a voltage and frequency control (VFC strategy for full converter (FC-based wind energy conversion systems (WECSs and its applicability for the supply of an isolated load. When supplying an isolated load, the role of the back-to-back converters in the FC must change with respect to a grid-connected application. Voltage and frequency are established by the FC line side converter (LSC, while the generator side converter (GSC is responsible for maintaining constant voltage in the DC link. Thus, the roles of the converters in the WECS are inverted. Under such control strategies, the LSC will automatically supply the load power and hence, in order to maintain a stable operation of the WECS, the wind turbine (WT power must also be controlled in a load-following strategy. The proposed VFC is fully modelled and a stability analysis is performed. Then, the operation of the WECS under the proposed VFC is simulated and tested on a real-time test bench, demonstrating the performance of the VFC for the isolated operation of the WECS.

  6. PV LED ENGINE characterization lab for stand alone light-to-light systems

    DEFF Research Database (Denmark)

    Poulsen, Peter Behrensdorff; Thorsteinsson, Sune; Lindén, Johannes

    2015-01-01

    dimming functions for reliable lighting. A barrier for exploiting use of standalone solar lighting for the urban environment seem to be lack of knowledge and lack of available tools for proper dimensioning. In this work the development of powerful dimensioning tool is described and initial measurements...... are presented. Furthermore, a laboratory has been build to characterize these systems up to 200 Wp from “nose to tail” in great details to support improvement of the systems and to make accurate field performance predictions by the dimensioning tool....

  7. Rancang Bangun Stand-Alone Automatic Rain Gauge (ARG Berbasis Panel Surya

    Directory of Open Access Journals (Sweden)

    Zaenal Arifin

    2017-11-01

    Full Text Available Automatic Rain Gauge (ARG digunakan untuk memonitor curah hujan di suatu wilayah. ARG bekerja dengan menggunakan mikrokontroller sebagai prosesing unit dan merupakan sebuah embedded sistem (sistem yang berdiri sendiri. ARG tidak hanya diletakan pada stasiun pemantauan Badan Meteorologi, Klimatologi dan Geofisika (BMKG, namun ARG juga diletakan di daerah terpencil yang jauh dari jaringan listrik. Hal tersebut menjadi masalah karena ARG membutuhkan sumber energi listrik untuk dapat bekerja. Berdasarkan spesifikasinya, ARG membutuhkan mikrokontroller yang rendah dalam penggunaan daya serta memiliki cukup memory sebagai tempat penyimpanan data sementara. Salah satu jenis mikrokrontroller yang memenuhi spesifikasi tersebut adalah MSP430FR5969. Dari penelitian yang telah dilakukan, didapatkan hasil konsumsi daya rata – rata yang dibutuhkan oleh ARG sebesar 0.23 watt. Dengan memanfaatkan panel surya sebesar 20 watt yang dilengkapi dengan maximum power point tracking (MPPT sebagai sumber energi listrik, dapat menghasilkan daya 5,5 watt hingga 7,2 watt. Dengan perbandingan data konsumsi energi dan data yang dihasilkan dari solar panel panel, maka ARG memiliki sumber listrik mandiri untuk memenuhi kebutuhannya.

  8. Investigation of heating and cooling in a stand-alone high temperature PEM fuel cell system

    International Nuclear Information System (INIS)

    Zhang, Caizhi; Yu, Tao; Yi, Jun; Liu, Zhitao; Raj, Kamal Abdul Rasheedj; Xia, Lingchao; Tu, Zhengkai; Chan, Siew Hwa

    2016-01-01

    Highlights: • Heating-up and cooling-down processes of HT-PEMFC are the mainly interested topics. • Dynamic behaviours, power and energy demand of the heating and cooling was studied. • Hybrid system based on LiFeYPO_4 battery for heating and cooling is built and tested. • The concept of combining different heating sources together is recommended. - Abstract: One key issue pertaining to the cold-start of High temperature PEM fuel cell (HT-PEMFC) is the requirement of high amount of thermal energy for heating up the stack to a temperature of 120 °C or above before it can generate electricity. Furthermore, cooling down the stack to a certain temperature (e.g. 50 °C) is necessary before stopping. In this study, the dynamic behaviours, power and energy demand of a 6 kW liquid cooled HT-PEMFC stack during heating-up, operation and cooling-down were investigated experimentally. The dynamic behaviours of fuel cell under heating-up and cooling-down processes are the mainly interested topics. Then a hybridisation of HT-PEMFC with Li-ion battery to demonstrate the synergistic effect on dynamic behaviour was conducted and validated for its feasibility. At last, the concept of combining different heating sources together is analysed to reduce the heating time of the HT-PEMFC as well.

  9. Analysis and optimization of hybrid excitation permanent magnet synchronous generator for stand-alone power system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huijun, E-mail: huijun024@gmail.com [School of Instrumentation Science and Opto-electronics Engineering, Beihang University (China); Qu, Zheng; Tang, Shaofei; Pang, Mingqi [School of Instrumentation Science and Opto-electronics Engineering, Beihang University (China); Zhang, Mingju [Shanghai Aerospace Control Technology Institute, Shanghai (China)

    2017-08-15

    Highlights: • One novel permanent magnet generator structure has been proposed to reduce voltage regulation ratio. • Finite element method and equivalent circuit methods are both employed to realize rapid generator design. • Design of experiment (DOE) method is used to optimize permanent magnet shape for reduce voltage waveform distortion. • The obtained analysis and experiment results verify the proposed design methods. - Abstract: In this paper, electromagnetic design and permanent magnet shape optimization for permanent magnet synchronous generator with hybrid excitation are investigated. Based on generator structure and principle, design outline is presented for obtaining high efficiency and low voltage fluctuation. In order to realize rapid design, equivalent magnetic circuits for permanent magnet and iron poles are developed. At the same time, finite element analysis is employed. Furthermore, by means of design of experiment (DOE) method, permanent magnet is optimized to reduce voltage waveform distortion. Finally, the validity of proposed design methods is validated by the analytical and experimental results.

  10. Fuzzy Secondary Controller for Autonomous Stand-alone and Grid-connected AC Microgrid

    DEFF Research Database (Denmark)

    Neves, Rodolpho V. A.; Machado, Ricardo Q.; Oliveira, Vilma A.

    2016-01-01

    The present paper adresses the AC microgrid control issue using the hierarchical control structure and droop controllers for load sharing. Once the droop controllers impose an operation with frequency and voltage deviations, depending on the load and droop parameters, a hierarchical control...... structure must be added to change the droop controller operating points. The hierarchical controllers operate with local measurements and shared signals from communication links among the distributed generation systems connected to the microgrid. Depending on the geographical size of the microgrid......, the communication links can be economically unviable. This paper thus proposes a fuzzy secondary controller for AC microgrids to reduce the link communication dependency by using only local measurements. The simulation results show that the deviations as happened with the conventional secondary controllers can...

  11. Simulation of a stand-alone renewable hydrogen system for residential supply

    Directory of Open Access Journals (Sweden)

    Martín Hervello

    2014-01-01

    Full Text Available La simulación por ordenador es un primer paso lógico previo a la realización de un proyecto de una construcción física además de ser una herramienta para el diseño de redes de energía. Los sistemas combinados son una solución para mejorar la disponibilidad de la energía suministrada con medios renovables. El principal inconveniente de las fuentes de energías renovables es su naturaleza altamente estacional, con grandes variaciones en el tiempo que pueden impedir el uso como base de consumo y limitar las horas de máxima demanda. El objetivo de este trabajo es realizar simulaciones para comprobar la autosuficiencia energética de una vivienda unifamiliar en base a energías renovables (eólica, solar-fotovoltaica utilizando como medio de almacenamiento un sistema híbrido de baterías e hidrógeno. Para ello se ha utilizado el programa Simulink®-Matlab® teniendo en cuenta los datos meteorológicos proporcionados por METEO-Galicia. El modelo puede ser aplicado para determinar la viabilidad de implementar una red energética en regiones específicas, y predecir el flujo de energía y el comportamiento del sistema durante todo el año.

  12. Photovoltaic OLED Driver for Low-Power Stand-Alone Light-to-Light Systems

    DEFF Research Database (Denmark)

    Ploug, Rasmus Overgaard; Knott, Arnold

    2016-01-01

    of a three-port-converter for this purpose optimized for the specifications for driving an Organic Light Emitting Diode (OLED) panel intended for lighting purposes. By using a three-port-converter, featuring shared components for each conversion mode, the converter reaches 97 % efficiency at 1.8 W during...... conversion from photovoltaic panel to the battery, and 97 % in the area 1.4 W to 2 W for power delivery to the OLED....

  13. Stand alone power system coupling a PV field and a fuel cell: first experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Busquet, S.; Labbe, J.; Leroux, P.; Metkemeijer, R.; Mayer, D. [ENSMP-CENERG, Sophia Antipolis (France)

    2003-07-01

    The purpose of the work, through the PVFC-SYS project, is to optimise the operation of a system coupling a photovoltaic field, an electrolyser, a gas storage, a fuel cell and a power management unit. A test bench is at present finalised in the Laboratory. All components have been selected for an optimal, automatic, safe and reliable operation of the complete system. Fully instrumented, this test bench furnishes new data concerning each component and the complete system behaviour for variable real weather conditions and different load demands. The paper describes the test bench, the simulation tool based on empirical model fitted to the component experimental data and the complete system performance for different load profiles along a year of operation. (orig.)

  14. Study on unitized inverter with photovoltaic grid-connected and stand-alone functions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haining; Su, Jianhui; Ding, Ming [Hefei University of Technology, Hefei (China)

    2008-07-01

    The main circuit and algorithm of unitized single phase inverter are presented, in which photovoltaic (PV) grid-connected algorithm, independency sine inverter algorithm and storage battery charge administer are all integrated basing on DSP (Digital Signal Processor). The control system identifies utility failure initiatively and then switches to independency power supply automatically. The methods of charging battery are multiform. Basing on material term to use utility or solar array to charge can optimize charge efficiency, assure the capacitance of battery and prolong life-span of battery. In addition, some results are offered basing on the prototype of a 2.5kW single phase inverter. (orig.)

  15. Development of a stand-alone microcomputer based DOE contractor generic radiation worker safety course

    International Nuclear Information System (INIS)

    Klos, D.B.; Gardner, P.R.

    1985-01-01

    Westinghouse Hanford Company (WHC) has developed Computer Based Training (CBT) materials for radiation and industrial safety. First released for general Fast Flux Test Facility in November, 1984. This course has now been taken by nearly 350 people. Completion times for new personnel average around eight hours. The next project undertaken was construction of a Radiation Worker Safety course generic enough for use by all contractors at the Hanford site. The design process of the Hanford site course indicated that the quantity of ''DOE common material'' may be sufficient to warrant consideration of a larger target population. Specifically, the course will be designed to run on an IBM-PC or compatible computer having 256K RAM, a standard IBM color graphics card or equivalent, a color graphics monitor, and two floppy disk drives or one hard disk. The target student population includes those who routinely work in Radiation Areas, especially crafts people. We are not targeting Health Physics personnel, except, possibly, for introductory training, nor are we directing the course toward ''casual'' or escorted workers

  16. The children left to stand alone | Roalkvam | African Journal of AIDS ...

    African Journals Online (AJOL)

    Drawing upon ethnographic fieldwork in Seke, a semi-rural area outside Harare, Zimbabwe, this paper explores the social mechanism behind the seeming invisibility of children left on their own and how this form of 'invisibility' challenges established notions of childhood, parenthood, kinship, and community. It argues that ...

  17. Comparing Memory-Efficient Genome Assemblers on Stand-Alone and Cloud Infrastructures

    KAUST Repository

    Kleftogiannis, Dimitrios A.; Kalnis, Panos; Bajic, Vladimir B.

    2013-01-01

    methodologies, we propose two general assembly strategies that can improve short-read assembly approaches and result in reduction of the memory footprint. Finally, we discuss the possibility of utilizing cloud infrastructures for genome assembly and we comment

  18. An ArcGIS analysis of Stand-alone GPS quality for Road Pricing

    DEFF Research Database (Denmark)

    Zabic, Martina

    2006-01-01

    The paper presents the methods and some of the result maps from a study of GPS quality in relation to road pricing in a dense urban area. Data from 500 cars were colleted over a two-year period in the Copenhagen region (Denmark). The data was analyzed in ArcGIS in order to determine whether the GPS...... quality and reliability is adequate for implementation of a road pricing system. The GPS log files was imported into ArcGIS and analyzed in relation to the digital road network and the density of the high rise areas in order to examine where the high buildings and narrow street canyons causes too many...

  19. Kajian Pemanfaatan Stand Alone Photovoltaic System Untuk Penerangan Jalan Umum Di Pulau Nusa Penida

    Directory of Open Access Journals (Sweden)

    I.W. Yudi Martha Wiguna

    2012-12-01

    Full Text Available   Nusa Penida merupakan sebuah pulau di tenggara pulau Bali dengan jumlah penduduk 47.448 jiwa. Ketersediaan daya pembangkit PLN di pulau Nusa Penida adalah sebesar 3200 kW. Dengan beban puncak sebesar 2530 kW maka cadangan listrik saat ini hanya sebesar 670 kW. Hal itu menyebabkan krisis listrik sangat terasa bagi masyarakat di daerah terpencil seperti di Pulau Nusa Penida. Saat ini salah satu solusi yang memungkinkan adalah mengembangkan sumber energi terbarukan. Di Pulau Nusa Penida sudah dikembangkan PLTS. Bahkan PLTS di Pulau Nusa Penida dikembangkan juga pada sistem penerangan jalan umum. Pada penelitian ini dilakukan analisa teknis dan biaya untuk mengetahui kelayakan Sistem PJU-TS tersebut. Pada analisa teknis dilakukan pengukuran output tegangan dan arus dari PV Panel ke Charger Controller, dari Charger Controller ke baterai dan ke beban. Analisa teknis menghasilkan bahwa penyebab kerusakan baterai karena kapasitas pembangkitan tidak sebanding dengan kebutuhan kapasitas beban PJU-TS. Dengan kapasitas baterai yang terus kecil akan menyebabkan kerusakan pada baterai. Selain itu karena usia baterai yang sudah lama. Analisa biaya dilakukan dengan 3 skenario dengan tingkat IRR yang ingin dicapai sebesar 10, 11, dan 12 %. Dihasilkan harga jual yang pantas untuk energi listrik PJU-TS Nusa Penida berkisar antara Rp.29.194,00 s/d Rp.31.585,00 per kWh.

  20. SAMAC program: the computer support for a stand-alone monitoring and control system

    International Nuclear Information System (INIS)

    Logg, C.A.

    1979-12-01

    The high energy physics experiments at SLAC require constant monitoring and control of the numerous components contained in the particle detection apparatus. This paper describes a basic hardware configuration and operating system which have been designed and implemented to satisfy the monitoring and control requirements of the many different setups used in these high energy physics experiments. It is based on the LSI-11 microprocessor with up to one million words of RAM and EPROM which are interchangeably mappable into the normal LSI-11 RAM/EPROM address space of 28K words. The entire system is modular in hardware and software so that it can easily be tailored to an individual experiment. The human interface is such that little training is required for effective use of the system

  1. Stand-alone and Interdisciplinary Course Design for Engineering Education for Sustainable Development

    DEFF Research Database (Denmark)

    Arsat, M.; Holgaard, Jette Egelund; de Graaff, Erik

    discipline or to fit across programmes. At Aalborg University (AAU), Denmark, which has a long tradition of problem based learning (PBL), a comprehensive sustainability course has been introduced to fit all students not at least across programmes but also across faculties of engineering, humanities...

  2. Battery Storage Technologies for Electrical Applications: Impact in Stand-Alone Photovoltaic Systems

    OpenAIRE

    Daniel Akinyele; Juri Belikov; Yoash Levron

    2017-01-01

    Batteries are promising storage technologies for stationary applications because of their maturity, and the ease with which they are designed and installed compared to other technologies. However, they pose threats to the environment and human health. Several studies have discussed the various battery technologies and applications, but evaluating the environmental impact of batteries in electrical systems remains a gap that requires concerted research efforts. This study first presents an ove...

  3. Analysis and optimization of hybrid excitation permanent magnet synchronous generator for stand-alone power system

    International Nuclear Information System (INIS)

    Wang, Huijun; Qu, Zheng; Tang, Shaofei; Pang, Mingqi; Zhang, Mingju

    2017-01-01

    Highlights: • One novel permanent magnet generator structure has been proposed to reduce voltage regulation ratio. • Finite element method and equivalent circuit methods are both employed to realize rapid generator design. • Design of experiment (DOE) method is used to optimize permanent magnet shape for reduce voltage waveform distortion. • The obtained analysis and experiment results verify the proposed design methods. - Abstract: In this paper, electromagnetic design and permanent magnet shape optimization for permanent magnet synchronous generator with hybrid excitation are investigated. Based on generator structure and principle, design outline is presented for obtaining high efficiency and low voltage fluctuation. In order to realize rapid design, equivalent magnetic circuits for permanent magnet and iron poles are developed. At the same time, finite element analysis is employed. Furthermore, by means of design of experiment (DOE) method, permanent magnet is optimized to reduce voltage waveform distortion. Finally, the validity of proposed design methods is validated by the analytical and experimental results.

  4. X-ray microbeam stand-alone facility for cultured cells irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bożek, Sebastian, E-mail: sebastian.bozek@yahoo.com [Jagiellonian University Medical College, Department of Pharmaceutical Biophysics, Krakow (Poland); Bielecki, Jakub; Wiecheć, Anna; Lekki, Janusz; Stachura, Zbigniew; Pogoda, Katarzyna; Lipiec, Ewelina; Tkocz, Konrad; Kwiatek, Wojciech M. [Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow (Poland)

    2017-03-01

    Highlights: • An X-ray microbeam line for irradiation of living cultured cells was constructed. • A step by step explanation of working principles with engineering details, procedures and calculations is presented. • A model of beam and cell interaction is presented. • A method of uniform irradiation of living cells with an exact dose per a cell is presented. • Results of preliminary experiments are presented. - Abstract: The article describes an X-ray microbeam standalone facility dedicated for irradiation of living cultured cells. The article can serve as an advice for such facilities construction, as it begins from engineering details, through mathematical modeling and experimental procedures, ending up with preliminary experimental results and conclusions. The presented system consists of an open type X-ray tube with microfocusing down to about 2 μm, an X-ray focusing system with optical elements arranged in the nested Kirckpatrick-Baez (or Montel) geometry, a sample stand and an optical microscope with a scientific digital CCD camera. For the beam visualisation an X-ray sensitive CCD camera and a spectral detector are used, as well as a scintillator screen combined with the microscope. A method of precise one by one irradiation of previously chosen cells is presented, as well as a fast method of uniform irradiation of a chosen sample area. Mathematical models of beam and cell with calculations of kerma and dose are presented. The experiments on dose-effect relationship, kinetics of DNA double strand breaks repair, as well as micronuclei observation were performed on PC-3 (Prostate Cancer) cultured cells. The cells were seeded and irradiated on Mylar foil, which covered a hole drilled in the Petri dish. DNA lesions were visualised with γ-H2AX marker combined with Alexa Fluor 488 fluorescent dye.

  5. The Small, Stand-Alone Early College: Impact on High School Outcomes

    Science.gov (United States)

    Glennie, Elizabeth; Unlu, Fatih; Furey, Jane

    2016-01-01

    North Carolina's Early College model is the subject of an IES-funded eleven-year longitudinal experimental study that utilized a lottery process to assign early college applicants to either treatment or control groups. This paper presents findings related to high school outcomes. The primary goal of the early college model is to increase the…

  6. The Small, Stand-Alone Early College: Impact on Postsecondary Outcomes

    Science.gov (United States)

    Unlu, Fatih; Furey, Jane

    2016-01-01

    This paper presents results from the longitudinal experimental study conducted on North Carolina's early college model described in an earlier paper. The primary purpose of this paper is to present the impact of the early college model on outcomes related to postsecondary enrollment. The specific research questions driving this study include: (1)…

  7. Stand-alone error characterisation of microwave satellite soil moisture using a Fourier method

    Science.gov (United States)

    Error characterisation of satellite-retrieved soil moisture (SM) is crucial for maximizing their utility in research and applications in hydro-meteorology and climatology. Error characteristics can provide insights for retrieval development and validation, and inform suitable strategies for data fus...

  8. A stand-alone track reconstruction algorithm for the scintillating fibre tracker at the LHCb upgrade

    CERN Multimedia

    Quagliani, Renato

    2017-01-01

    The LHCb upgrade detector project foresees the presence of a scintillating fiber tracker (SciFi) to be used during the LHC Run III, starting in 2020. The instantaneous luminosity will be increased up to $2\\times10^{33}$, five times larger than in Run II and a full software event reconstruction will be performed at the full bunch crossing rate by the trigger. The new running conditions, and the tighter timing constraints in the software trigger, represent a big challenge for track reconstruction. This poster presents the design and performance of a novel algorithm that has been developed to reconstruct track segments using solely hits from the SciFi. This algorithm is crucial for the reconstruction of tracks originating from long-lived particles such as $K_{S}^{0}$ and $\\Lambda$ and allows to greatly enhance the physics potential and capabilities of the LHCb upgrade when compared to its previous implementation.

  9. Comparing Memory-Efficient Genome Assemblers on Stand-Alone and Cloud Infrastructures

    KAUST Repository

    Kleftogiannis, Dimitrios A.

    2013-09-27

    A fundamental problem in bioinformatics is genome assembly. Next-generation sequencing (NGS) technologies produce large volumes of fragmented genome reads, which require large amounts of memory to assemble the complete genome efficiently. With recent improvements in DNA sequencing technologies, it is expected that the memory footprint required for the assembly process will increase dramatically and will emerge as a limiting factor in processing widely available NGS-generated reads. In this report, we compare current memory-efficient techniques for genome assembly with respect to quality, memory consumption and execution time. Our experiments prove that it is possible to generate draft assemblies of reasonable quality on conventional multi-purpose computers with very limited available memory by choosing suitable assembly methods. Our study reveals the minimum memory requirements for different assembly programs even when data volume exceeds memory capacity by orders of magnitude. By combining existing methodologies, we propose two general assembly strategies that can improve short-read assembly approaches and result in reduction of the memory footprint. Finally, we discuss the possibility of utilizing cloud infrastructures for genome assembly and we comment on some findings regarding suitable computational resources for assembly.

  10. Experimental stand-alone self-excited induction generator driven by a diesel motor

    Directory of Open Access Journals (Sweden)

    Mhamdi Taoufik

    2017-12-01

    Full Text Available This paper presents an experimental work to design and size a diesel generator (DG. The basic system is equipped with a 1.5 kW self-excited induction generator (SEIG, a diesel motor (DM, a static voltage compensator (SVC and controllers. A proportional integral controller is used to meet the requirement of the SEIG frequency regulation. A controlled voltage source is performed by using an SVC with a fuzzy controller, which adjusts voltage by varying the amount of the injected reactive power. An experimental set-up is used to identify the SEIG parameters and select the convenient bank of capacitors that minimize the SEIG starting up time and fix the convenient margin of voltage. The system has been tested by simulation using models implemented by Matlab/Simulink software. The simulation results confirm the efficiency of the proposed strategy of voltage regulation. Keywords: Diesel motor, SEIG, SVC, Voltage regulation, Frequency regulation

  11. SSTAR, a Stand-Alone Easy-To-Use Antimicrobial Resistance Gene Predictor.

    Science.gov (United States)

    de Man, Tom J B; Limbago, Brandi M

    2016-01-01

    We present the easy-to-use Sequence Search Tool for Antimicrobial Resistance, SSTAR. It combines a locally executed BLASTN search against a customizable database with an intuitive graphical user interface for identifying antimicrobial resistance (AR) genes from genomic data. Although the database is initially populated from a public repository of acquired resistance determinants (i.e., ARG-ANNOT), it can be customized for particular pathogen groups and resistance mechanisms. For instance, outer membrane porin sequences associated with carbapenem resistance phenotypes can be added, and known intrinsic mechanisms can be included. Unique about this tool is the ability to easily detect putative new alleles and truncated versions of existing AR genes. Variants and potential new alleles are brought to the attention of the user for further investigation. For instance, SSTAR is able to identify modified or truncated versions of porins, which may be of great importance in carbapenemase-negative carbapenem-resistant Enterobacteriaceae. SSTAR is written in Java and is therefore platform independent and compatible with both Windows and Unix operating systems. SSTAR and its manual, which includes a simple installation guide, are freely available from https://github.com/tomdeman-bio/Sequence-Search-Tool-for-Antimicrobial-Resistance-SSTAR-. IMPORTANCE Whole-genome sequencing (WGS) is quickly becoming a routine method for identifying genes associated with antimicrobial resistance (AR). However, for many microbiologists, the use and analysis of WGS data present a substantial challenge. We developed SSTAR, software with a graphical user interface that enables the identification of known AR genes from WGS and has the unique capacity to easily detect new variants of known AR genes, including truncated protein variants. Current software solutions do not notify the user when genes are truncated and, therefore, likely nonfunctional, which makes phenotype predictions less accurate. SSTAR users can apply any AR database of interest as a reference comparator and can manually add genes that impact resistance, even if such genes are not resistance determinants per se (e.g., porins and efflux pumps).

  12. Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications

    International Nuclear Information System (INIS)

    Tam, S.W.

    1997-01-01

    Disclosed is an illumination source comprising a porous silicon having a source of electrons on the surface and/or interstices thereof having a total porosity in the range of from about 50 v/o to about 90 v/o. Also disclosed are a tritiated porous silicon and a photovoltaic device and an illumination source of tritiated porous silicon. 1 fig

  13. Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications

    Science.gov (United States)

    Tam, Shiu-Wing

    1997-01-01

    An illumination source comprising a porous silicon having a source of electrons on the surface and/or interticies thereof having a total porosity in the range of from about 50 v/o to about 90 v/o. Also disclosed are a tritiated porous silicon and a photovoltaic device and an illumination source of tritiated porous silicon.

  14. The Politics of Education: Why Stand-Alone Youth Work Degrees Matter

    Science.gov (United States)

    Bessant, Judith

    2007-01-01

    While the demand in Australia for youth workers is growing, the education of youth workers in universities is being "rationalised" because these institutions have been fiscally squeezed by successive federal governments. What are the consequences for youth workers, young people and society as a whole if the move towards…

  15. Comparing memory-efficient genome assemblers on stand-alone and cloud infrastructures.

    Science.gov (United States)

    Kleftogiannis, Dimitrios; Kalnis, Panos; Bajic, Vladimir B

    2013-01-01

    A fundamental problem in bioinformatics is genome assembly. Next-generation sequencing (NGS) technologies produce large volumes of fragmented genome reads, which require large amounts of memory to assemble the complete genome efficiently. With recent improvements in DNA sequencing technologies, it is expected that the memory footprint required for the assembly process will increase dramatically and will emerge as a limiting factor in processing widely available NGS-generated reads. In this report, we compare current memory-efficient techniques for genome assembly with respect to quality, memory consumption and execution time. Our experiments prove that it is possible to generate draft assemblies of reasonable quality on conventional multi-purpose computers with very limited available memory by choosing suitable assembly methods. Our study reveals the minimum memory requirements for different assembly programs even when data volume exceeds memory capacity by orders of magnitude. By combining existing methodologies, we propose two general assembly strategies that can improve short-read assembly approaches and result in reduction of the memory footprint. Finally, we discuss the possibility of utilizing cloud infrastructures for genome assembly and we comment on some findings regarding suitable computational resources for assembly.

  16. Single-crate stand-alone CAMAC control system for a negative ion source test facility

    International Nuclear Information System (INIS)

    Juras, R.C.; Ziegler, N.F.

    1979-01-01

    A single-crate CAMAC system was configured to control a negative ion source development facility at ORNL and control software was written for the crate microcomputer. The software uses inputs from a touch panel and a shaft encoder to control the various operating parameters of the test facility and uses the touch panel to display the operating status. Communication to and from the equipment at ion source potential is accomplished over optical fibers from an ORNL-built CAMAC module. A receiver at ion source potential stores the transmitted data and some of these stored values are then used to control discrete parameters of the ion source (i.e., power supply on or off). Other stored values are sent to a multiplexed digital-to-analog converter to provide analog control signals. A transmitter at ion source potential transmits discrete status information and several channels of analog data from an analog-to-digital converter back to the ground-potential receiver where it is stored to be read and displayed by the software

  17. Control aspects of the Schuchuli Village stand-alone photovoltaic power system

    Science.gov (United States)

    Groumpos, P. P.; Culler, J. E.; Delombard, R.

    1984-11-01

    A photovoltaic power system in an Arizona Indian village was installed. The control subsystem of this photovoltaic power system was analyzed. The four major functions of the control subsystem are: (1) voltage regulation; (2) load management; (3) water pump control; and (4) system protection. The control subsystem functions flowcharts for the control subsystem operation, and a computer program that models the control subsystem are presented.

  18. An Approach for High-precision Stand-alone Positioning in a Dynamic Environment

    Science.gov (United States)

    Halis Saka, M.; Metin Alkan, Reha; Ozpercin, Alişir

    2015-04-01

    In this study, an algorithm is developed for precise positioning in dynamic environment utilizing a single geodetic GNSS receiver using carrier phase data. In this method, users should start the measurement on a known point near the project area for a couple of seconds making use of a single dual-frequency geodetic-grade receiver. The technique employs iono-free carrier phase observations with precise products. The equation of the algorithm is given below; Sm(t(i+1))=SC(ti)+[ΦIF (t(i+1) )-ΦIF (ti)] where, Sm(t(i+1)) is the phase-range between satellites and the receiver, SC(ti) is the initial range computed from the initial known point coordinates and the satellite coordinates and ΦIF is the ionosphere-free phase measurement (in meters). Tropospheric path delays are modelled using the standard tropospheric model. To accomplish the process, an in-house program was coded and some functions were adopted from Easy-Suite available at http://kom.aau.dk/~borre/easy. In order to assess the performance of the introduced algorithm in a dynamic environment, a dataset from a kinematic test measurement was used. The data were collected from a kinematic test measurement in Istanbul, Turkey. In the test measurement, a geodetic dual-frequency GNSS receiver, Ashtech Z-Xtreme, was set up on a known point on the shore and a couple of epochs were recorded for initialization. The receiver was then moved to a vessel and data were collected for approximately 2.5 hours and the measurement was finalized on a known point on the shore. While the kinematic measurement on the vessel were carried out, another GNSS receiver was set up on a geodetic point with known coordinates on the shore and data were collected in static mode to calculate the reference trajectory of the vessel using differential technique. The coordinates of the vessel were calculated for each measurement epoch with the introduced method. With the purpose of obtaining more robust results, all coordinates were calculated once again by inversely, i.e. from the last epoch to the first one. In this way, the estimated coordinates were also controlled. The average of both computed coordinates were used as vessel coordinates and then compared with the known-coordinates those of geodetic receiver epoch by epoch. The results indicate that the calculated coordinates from the introduced method are consistent with the reference trajectory with an accuracy of about 1 decimeter. In contrast, the findings imply lower accuracy for height components with an accuracy of about 2 decimeters. This accuracy level meets the requirement of many applications including some marine applications, precise hydrographic surveying, dredging, attitude control of ships, buoys and floating platforms, marine geodesy, navigation and oceanography.

  19. Bifacial PV cell with reflector for stand-alone mast for sensor powering purposes

    Science.gov (United States)

    Jakobsen, Michael L.; Thorsteinsson, Sune; Poulsen, Peter B.; Riedel, N.; Rødder, Peter M.; Rødder, Kristin

    2017-09-01

    Reflectors to bifacial PV-cells are simulated and prototyped in this work. The aim is to optimize the reflector to specific latitudes, and particularly northern latitudes. Specifically, by using minimum semiconductor area the reflector must be able to deliver the electrical power required at the condition of minimum solar travel above the horizon, worst weather condition etc. We will test a bifacial PV-module with a retroreflector, and compare the output with simulations combined with local solar data.

  20. Maximun power point tracker of photovoltaic s panels for stand alone systems

    International Nuclear Information System (INIS)

    Stoll, R; Manno, R

    2005-01-01

    The low energetic efficiency of photovoltaic s panels is known, in addition, due to the use of linear regulators, which dissipate an important bit of the generated energy, the efficiency of the photovoltaic systems is still smaller.Also, the I-V characteristic curve of the photovoltaic modules depends on the solar radiation and the own temperature; consequently, the maximum power point (Wp) changes permanently.In conclusion, to produce electricity with photovoltaic panels is very expensive. However due to preserve the environment this technology is widely used.With the purpose of optimizing the amount of energy produced by the photovoltaic system, two complementary methods are used.One is the Maximum Power Point Tracker (MPPT) system and the other one is the Solar Tracker system.The objective of this project is to reduce that cost increasing the amount of energy produced by the solar panels using a Maximum Power Point Tracker system.This device consists of a DC/DC buck converter of high performance, controlled by a PIC 16F873 micro controller; which carries out the conversions of the analogical signals of the solar array to digital signals (ADC), the PIC output digital signals to the PWM control of the power FET (DAC), and calculates the Duty Cycle (D) for the point of I-V curve where this product becomes maximum.Measurements for different loads and battery charges were made.With the obtained results, the comparisons with a conventional system were made, a greater cession of energy to the load is observed.The main conclusion of this work is: Using a MPPT device to making work the PV module during the greater possible time near the maximum power point, the efficiency of the photovoltaic systems can be increased

  1. Generalized Born-Infeld actions and projective cubic curves

    Energy Technology Data Exchange (ETDEWEB)

    Ferrara, S. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Porrati, M. [CCPP, Department of Physics, NYU, 4 Washington Pl., New York, NY, 10003 (United States); Sagnotti, A. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Stora, R. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Laboratoire d' Annecy-le-Vieux de Physique Theorique (LAPTH), F-74941, Annecy-le-Vieux, Cedex (France); Yeranyan, A. [INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89A, 00184, Roma (Italy)

    2015-04-01

    We investigate U(1){sup n} supersymmetric Born-Infeld Lagrangians with a second non-linearly realized supersymmetry. The resulting non-linear structure is more complex than the square root present in the standard Born-Infeld action, and nonetheless the quadratic constraints determining these models can be solved exactly in all cases containing three vector multiplets. The corresponding models are classified by cubic holomorphic prepotentials. Their symmetry structures are associated to projective cubic varieties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. 3D confocal imaging in CUBIC-cleared mouse heart

    Energy Technology Data Exchange (ETDEWEB)

    Nehrhoff, I.; Bocancea, D.; Vaquero, J.; Vaquero, J.J.; Lorrio, M.T.; Ripoll, J.; Desco, M.; Gomez-Gaviro, M.V.

    2016-07-01

    Acquiring high resolution 3D images of the heart enables the ability to study heart diseases more in detail. Here, the CUBIC (clear, unobstructed brain imaging cocktails and computational analysis) clearing protocol was adapted for thick mouse heart sections to increase the penetration depth of the confocal microscope lasers into the tissue. The adapted CUBIC clearing of the heart lets the antibody penetrate deeper into the tissue by a factor of five. The here shown protocol enables deep 3D highresolution image acquisition in the heart. This allows a much more accurate assessment of the cellular and structural changes that underlie heart diseases. (Author)

  3. Eisenstein Series Identities Involving the Borweins' Cubic Theta Functions

    Directory of Open Access Journals (Sweden)

    Ernest X. W. Xia

    2012-01-01

    Full Text Available Based on the theories of Ramanujan's elliptic functions and the (p, k-parametrization of theta functions due to Alaca et al. (2006, 2007, 2006 we derive certain Eisenstein series identities involving the Borweins' cubic theta functions with the help of the computer. Some of these identities were proved by Liu based on the fundamental theory of elliptic functions and some of them may be new. One side of each identity involves Eisenstein series, the other products of the Borweins' cubic theta functions. As applications, we evaluate some convolution sums. These evaluations are different from the formulas given by Alaca et al.

  4. Regularizing cubic open Neveu-Schwarz string field theory

    International Nuclear Information System (INIS)

    Berkovits, Nathan; Siegel, Warren

    2009-01-01

    After introducing non-minimal variables, the midpoint insertion of Y Y-bar in cubic open Neveu-Schwarz string field theory can be replaced with an operator N ρ depending on a constant parameter ρ. As in cubic open superstring field theory using the pure spinor formalism, the operator N ρ is invertible and is equal to 1 up to a BRST-trivial quantity. So unlike the linearized equation of motion Y Y-bar QV = 0 which requires truncation of the Hilbert space in order to imply QV = 0, the linearized equation N ρ QV = 0 directly implies QV = 0.

  5. 3D confocal imaging in CUBIC-cleared mouse heart

    International Nuclear Information System (INIS)

    Nehrhoff, I.; Bocancea, D.; Vaquero, J.; Vaquero, J.J.; Lorrio, M.T.; Ripoll, J.; Desco, M.; Gomez-Gaviro, M.V.

    2016-01-01

    Acquiring high resolution 3D images of the heart enables the ability to study heart diseases more in detail. Here, the CUBIC (clear, unobstructed brain imaging cocktails and computational analysis) clearing protocol was adapted for thick mouse heart sections to increase the penetration depth of the confocal microscope lasers into the tissue. The adapted CUBIC clearing of the heart lets the antibody penetrate deeper into the tissue by a factor of five. The here shown protocol enables deep 3D highresolution image acquisition in the heart. This allows a much more accurate assessment of the cellular and structural changes that underlie heart diseases. (Author)

  6. Total Positivity of the Cubic Trigonometric Bézier Basis

    Directory of Open Access Journals (Sweden)

    Xuli Han

    2014-01-01

    Full Text Available Within the general framework of Quasi Extended Chebyshev space, we prove that the cubic trigonometric Bézier basis with two shape parameters λ and μ given in Han et al. (2009 forms an optimal normalized totally positive basis for λ,μ∈(-2,1]. Moreover, we show that for λ=-2 or μ=-2 the basis is not suited for curve design from the blossom point of view. In order to compute the corresponding cubic trigonometric Bézier curves stably and efficiently, we also develop a new corner cutting algorithm.

  7. Preservation or Restoration of Segmental and Regional Spinal Lordosis Using Minimally Invasive Interbody Fusion Techniques in Degenerative Lumbar Conditions: A Literature Review.

    Science.gov (United States)

    Uribe, Juan S; Myhre, Sue Lynn; Youssef, Jim A

    2016-04-01

    A literature review. The purpose of this study was to review lumbar segmental and regional alignment changes following treatment with a variety of minimally invasive surgery (MIS) interbody fusion procedures for short-segment, degenerative conditions. An increasing number of lumbar fusions are being performed with minimally invasive exposures, despite a perception that minimally invasive lumbar interbody fusion procedures are unable to affect segmental and regional lordosis. Through a MEDLINE and Google Scholar search, a total of 23 articles were identified that reported alignment following minimally invasive lumbar fusion for degenerative (nondeformity) lumbar spinal conditions to examine aggregate changes in postoperative alignment. Of the 23 studies identified, 28 study cohorts were included in the analysis. Procedural cohorts included MIS ALIF (two), extreme lateral interbody fusion (XLIF) (16), and MIS posterior/transforaminal lumbar interbody fusion (P/TLIF) (11). Across 19 study cohorts and 720 patients, weighted average of lumbar lordosis preoperatively for all procedures was 43.5° (range 28.4°-52.5°) and increased 3.4° (9%) (range -2° to 7.4°) postoperatively (P lordosis increased, on average, by 4° from a weighted average of 8.3° preoperatively (range -0.8° to 15.8°) to 11.2° at postoperative time points (range -0.2° to 22.8°) (P lordosis and change in lumbar lordosis (r = 0.413; P = 0.003), wherein lower preoperative lumbar lordosis predicted a greater increase in postoperative lumbar lordosis. Significant gains in both weighted average lumbar lordosis and segmental lordosis were seen following MIS interbody fusion. None of the segmental lordosis cohorts and only two of the 19 lumbar lordosis cohorts showed decreases in lordosis postoperatively. These results suggest that MIS approaches are able to impact regional and local segmental alignment and that preoperative patient factors can impact the extent of correction gained

  8. Comparative Study of the Difference of Perioperative Complication and Radiologic Results: MIS-DLIF (Minimally Invasive Direct Lateral Lumbar Interbody Fusion) Versus MIS-OLIF (Minimally Invasive Oblique Lateral Lumbar Interbody Fusion).

    Science.gov (United States)

    Jin, Jie; Ryu, Kyeong-Sik; Hur, Jung-Woo; Seong, Ji-Hoon; Kim, Jin-Sung; Cho, Hyun-Jin

    2018-02-01

    Retrospective observatory analysis. The purpose of this study was to compare the incidence of perioperative complication, difference of cage location, and sagittal alignment between minimally invasive oblique lateral lumbar interbody fusion (MIS-OLIF) and MIS-direct lateral lumbar interbody fusion (DLIF) in the cases of single-level surgery at L4-L5. MIS-DLIF using tubular retractor has been used for the treatment of lumbar degenerative diseases; however, blunt transpsoas dissection poses a risk of injury to the lumbar plexus. As an alternative, MIS-OLIF uses a window between the prevertebral venous structures and psoas muscle. A total of 43 consecutive patients who underwent MIS-DLIF or MIS-OLIF for various L4/L5 level pathologies between November 2011 and April 2014 by a single surgeon were retrospectively reviewed. A complication classification based on the relation to surgical procedure and effect duration was used. Perioperative complications until 3-month postoperatively were reviewed for the patients. Radiologic results including the cage location and sagittal alignment were also assessed with plain radiography. There were no significant statistical differences in perioperative parameters and early clinical outcome between 2 groups. Overall, there were 13 (59.1%) approach-related complications in the DLIF group and 3 (14.3%) in the OLIF group. In the DLIF group, 3 (45.6%) were classified as persistent, however, there was no persistent complication in the OLIF group. In the OLIF group, cage is located mostly in the middle 1/3 of vertebral body, significantly increasing posterior disk space height and foraminal height compared with the DLIF group. Global and segmental lumbar lordosis was greater in the DLIF group due to anterior cage position without statistical significance. In our report of L4/L5 level diseases, the OLIF technique may decrease approach-related perioperative morbidities by eliminating the risk of unwanted muscle and nerve manipulations. Using

  9. Specific heat of the simple-cubic Ising model

    NARCIS (Netherlands)

    Feng, X.; Blöte, H.W.J.

    2010-01-01

    We provide an expression quantitatively describing the specific heat of the Ising model on the simple-cubic lattice in the critical region. This expression is based on finite-size scaling of numerical results obtained by means of a Monte Carlo method. It agrees satisfactorily with series expansions

  10. Higher-Order Approximation of Cubic-Quintic Duffing Model

    DEFF Research Database (Denmark)

    Ganji, S. S.; Barari, Amin; Babazadeh, H.

    2011-01-01

    We apply an Artificial Parameter Lindstedt-Poincaré Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillations with cubic-quintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations...

  11. C2-rational cubic spline involving tension parameters

    Indian Academy of Sciences (India)

    preferred which preserves some of the characteristics of the function to be interpolated. In order to tackle such ... Shape preserving properties of the rational (cubic/quadratic) spline interpolant have been studied ... tension parameters which is used to interpolate the given monotonic data is described in. [6]. Shape preserving ...

  12. Initial post dynamic buckling of a quadratic-cubic column ...

    African Journals Online (AJOL)

    In this investigation, we determine the dynamic buckling load of an imperfect finite column resting on a mixed quadratic-cubic nonlinear elastic foundation trapped by an explicitly time dependent sinusoidally slowly varying dynamic load .The resultant coefficients are dynamically slowly varying and the formulation contains ...

  13. Phonons in face-centred cubic calcium and strontium

    International Nuclear Information System (INIS)

    Singh, S.P.; Rathore, R.P.S.

    1984-01-01

    The axially symmetric and unpaired forces are employed to analyse the phonon dispersion and elastic behaviour of face centred cubic calcium and strontium which have so far not been studied adequately. The model with three parameters predicts the results which agree marvellously with the recently measured data. (author)

  14. One billion cubic meters of gas produced in Kikinda area

    Energy Technology Data Exchange (ETDEWEB)

    Vicicevic, M; Duric, N

    1969-10-01

    The Kikinda gas reservoir has just passed a milestone in producing one billion cubic meters of natural gas. The reservoir was discovered in 1962, and its present production amounts to 26 million cu m. One of the biggest problems was formation of hydrates, which has successfully been solved by using methanol. Four tables show production statistics by years and productive formations.

  15. Physical vapor deposition of cubic boron nitride thin films

    International Nuclear Information System (INIS)

    Kester, D.J.

    1991-01-01

    Cubic boron nitride was successfully deposited using physical vapor-deposition methods. RF-sputtering, magnetron sputtering, dual-ion-beam deposition, and ion-beam-assisted evaporation were all used. The ion-assisted evaporation, using boron evaporation and bombardment by nitrogen and argon ions, led to successful cubic boron nitride growth over the widest and most controllable range of conditions. It was found that two factors were important for c-BN growth: bombardment of the growing film and the presence of argon. A systematic study of the deposition conditions was carried out. It was found that the value of momentum transferred into the growing from by the bombarding ions was critical. There was a very narrow transition range in which mixed cubic and hexagonal phase films were prepared. Momentum-per-atom value took into account all the variables involved in ion-assisted deposition: deposition rate, ion energy, ion flux, and ion species. No other factor led to the same control of the process. The role of temperature was also studied; it was found that at low temperatures only mixed cubic and hexagonal material are deposited

  16. Particle Creation in Oscillating Cavities with Cubic and Cylindrical Geometry

    Science.gov (United States)

    Setare, M. R.; Dinani, H. T.

    2008-04-01

    In the present paper we study the creation of massless scalar particles from the quantum vacuum due to the dynamical Casimir effect by oscillating cavities with cubic and cylindrical geometry. To the first order of the amplitude we derive the expressions for the number of the created particles.

  17. Global Well-Posedness for Cubic NLS with Nonlinear Damping

    KAUST Repository

    Antonelli, Paolo

    2010-11-04

    We study the Cauchy problem for the cubic nonlinear Schrödinger equation, perturbed by (higher order) dissipative nonlinearities. We prove global in-time existence of solutions for general initial data in the energy space. In particular we treat the energy-critical case of a quintic dissipation in three space dimensions. © Taylor & Francis Group, LLC.

  18. Influence of strontium on the cubic to ordered hexagonal phase

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 23; Issue 6. Influence of strontium on the cubic to ordered hexagonal phase transformation in barium magnesium niobate. M Thirumal A K Ganguli. Phase Transitions Volume 23 Issue 6 December 2000 pp 495-498 ...

  19. Exact solutions for the cubic-quintic nonlinear Schroedinger equation

    International Nuclear Information System (INIS)

    Zhu Jiamin; Ma Zhengyi

    2007-01-01

    In this paper, the cubic-quintic nonlinear Schroedinger equation is solved through the extended elliptic sub-equation method. As a consequence, many types of exact travelling wave solutions are obtained which including bell and kink profile solitary wave solutions, triangular periodic wave solutions and singular solutions

  20. Estimating the board foot to cubic foot ratio

    Science.gov (United States)

    Steve P. Verrill; Victoria L. Herian; Henry N. Spelter

    2004-01-01

    Certain issues in recent softwood lumber trade negotiations have centered on the method for converting estimates of timber volumes reported in cubic meters to board feet. Such conversions depend on many factors; three of the most important of these are log length, diameter, and taper. Average log diameters vary by region and have declined in the western United States...