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1

Comparing wind and photovoltaic stand-alone power systems used for the electrification of remote consumers  

Microsoft Academic Search

Wind power and photovoltaic driven stand-alone systems have turned into one of the most promising ways to handle the electrification requirements of numerous isolated consumers worldwide. In this context, the primary target of the present work is to estimate the appropriate dimensions of either a wind power or a photovoltaic stand-alone system that guarantees the energy autonomy of several typical

J. K. Kaldellisa; K. A. Kavadias; P. S. Koronakis

2007-01-01

2

SMALL SIGNAL STABILITY ANALYSIS OF STAND ALONE POWER SYSTEM WITH DISTRIBUTED GENERATION  

Microsoft Academic Search

Stand alone power system with distributed generation is a useful and reliable way to supply energy in critical and rural district with less cost and pollution, better power quality than conventional power station. Transmission and distribution rating voltage of stand alone system is 10kV and 380V. The ratio of Resistance to reactance in LV&MV line is larger than that of

SHENG Kun; KONG Li; PEI Wei

3

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

Microsoft Academic Search

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

Shameem Ahmad Lone; Mairaj Ud-Din Mufti

2006-01-01

4

A systems approach for sizing a stand-alone residential PEMFC power system  

Microsoft Academic Search

Polymer electrolyte membrane fuel cells (PEMFCs) show great promise in portable, automotive, and stationary applications. They have reached the test and demonstration phase in automotive and power markets today. This paper is focused on a stand-alone residential PEMFC power system that provides the electricity needs of the house. A novel stochastic sizing methodology is developed that considers both fuel cell

U?ur S. Selamo?ullar?; Thomas R. Willemain; David A. Torrey

2007-01-01

5

A Systems Approach for a Stand-Alone Residential Fuel Cell Power Inverter Design  

Microsoft Academic Search

Analysis of an experimentally measured daily load profile reveals that the residential power demand has a high percentage of low power duration over a day. In a stand-alone residential fuel cell power system, the power inverter designed for the peak power requirement will be operating at light loads, where its efficiency is lower, most of the time. Thus, improving the

Ugur Savas Selamogullari; David A. Torrey; Sheppard Salon

2010-01-01

6

Soft Phase Locked Loop for Active Power Filter Applied in Small Rating Stand-alone Power System  

Microsoft Academic Search

Traditional LC filters can't work stably in small rating stand-alone power system. So active power filter (APF) is becoming an important tool to solve the power quality problem in small rating stand-alone power system. In this paper the influence of the synchronizing signal error on current detection of APF is analyzed. Voltage distortion, voltage unbalance and frequency fluctuation are frequent

Wu Longhui; Zhuo Fang; Wang Zhaoan

2007-01-01

7

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

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

8

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

NASA Astrophysics Data System (ADS)

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.

Philippi, T. M.

1981-11-01

9

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

SciTech Connect

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.

Not Available

1980-07-01

10

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

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

11

Current status of research on optimum sizing of stand-alone hybrid solar–wind power generation systems  

Microsoft Academic Search

Solar and wind energy systems are omnipresent, freely available, environmental friendly, and they are considered as promising power generating sources due to their availability and topological advantages for local power generations. Hybrid solar–wind energy systems, uses two renewable energy sources, allow improving the system efficiency and power reliability and reduce the energy storage requirements for stand-alone applications. The hybrid solar–wind

Wei Zhou; Chengzhi Lou; Zhongshi Li; Lin Lu; Hongxing Yang

2010-01-01

12

Design study of a stand-alone desalination system powered by renewable energy sources and a pumped storage unit  

Microsoft Academic Search

The aim of this work is to investigate in detail the optimum design and operation strategy of a stand-alone hybrid desalination scheme, capable to fulfill the fresh water demand of an island or other remote coastal regions. The scheme consists of a reverse-osmosis desalination unit powered by wind and solar electricity production systems and by a pumped storage unit.A specific

Ioannis D. Spyrou; John S. Anagnostopoulos

2010-01-01

13

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

Microsoft Academic Search

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

Yan Jia; Ryosuke Shibata; Naoki Yamamura; Muneaki Ishida

2007-01-01

14

A Study on Electric Power Smoothing System for Lead-acid Battery of Stand-alone Natural Energy Power System Using EDLC  

Microsoft Academic Search

In Stand-alone Natural Energy Power System (SNEPS), the earlier deterioration of lead-acid battery caused by over recycle times has become the main problems that need to be resolved urgently. Fluctuating power of short period of power supply is one of the main reason of recharge cycle times increasing. Hence, to smooth the fluctuating power, improve power quality and prolong the

Yan Jia; K. Oti; N. Yamamura; M. Ishida

2007-01-01

15

Implementation of a stand-alone photovoltaic pumping system with maximum power point tracking  

Microsoft Academic Search

Photovoltaic (PV) pumping systems using a maximum power point tracking (MPPT) technique aim to obtain the highest possible power to the pump under various insolation and temperature conditions, thus overcoming the mismatch between the photovoltaic panel and the pumping load. A simple method of tracking the maximum power points and forcing the system to operate close to these points is

Chen Kunlun; Zhao Zhengming; Yuan Liqiang

2001-01-01

16

Stand-Alone Flat-Plate Photovoltaic Power Systems: System Sizing and Life-Cycle Costing Methodology for Federal Agencies.  

National Technical Information Service (NTIS)

A simple methodology to estimate photovoltaic system size and life-cycle costs in stand-along applications is presented in this document. It is designed to assist engineers at government agencies in determining the feasibility of using small stand-alone p...

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

1984-01-01

17

A high-performance stand-alone solar PV power system for LED lighting  

Microsoft Academic Search

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

B. J. Huang; P. C. Hsu; M. S. Wu; K. Y. Chen

2010-01-01

18

Dynamic operation and control of a hybrid wind-diesel stand alone power systems  

Microsoft Academic Search

This paper presents the dynamic operation and control strategies of a hybrid wind-diesel-battery energy storage based power supply system for isolated communities are investigated. Control strategies for voltage and frequency stabilization and efficient power flow among the hybrid system components are developed. The voltage and frequency of the hybrid wind-diesel system is controlled either by a load side inverter or

A. M. O. Haruni; A. Gargoom; M. E. Haque; M. Negnevitsky

2010-01-01

19

Medium power wind mill control for stand alone energy generation  

Microsoft Academic Search

This paper will propose the study of a the control of a coupled wind turbine to a stand alone electric generator based on other renewable energies and storage systems. In this study a new method has been investigated to design the maximum power point tracking (MPPT) in order to have a good efficiency with a simple approach. From the wind

O. Ba; D. Depernet; P. Ndiaye; A. Berthon

2009-01-01

20

Developed Algorithm of Maximum Power Tracking for Stand-Alone Photovoltaic System  

Microsoft Academic Search

The rapid increase in the cost of conventional energy sources leads to the use of nonconventional energy sources. The photovoltaic (PV) is one nonconventional source that is safe, reliable, and environmentally healthy. However, the PV system is expensive and needs a large area to operate. To solve these disadvantages, it is necessary to operate at the maximum power point (MPP)

ABD EL-SHAFY A. NAFEH; FATEN H. FAHMY; OSAMA A. MAHGOUB; ESSAM M. ABOU EL-ZAHAB

1998-01-01

21

Optimal sizing of battery storage for stand-alone hybrid (photo-voltaic + diesel) power systems  

NASA Astrophysics Data System (ADS)

An important element of hybrid photo- voltaic(PV) + diesel sytem is battery storage. Size of battery storage plays a role in optimum operation of the hybrid system. Emphasis needs to be placed on this issue. In this perspective, hourly solar radiation data, for the period 1986 93 recorded at Dhahran, Saudi Arabia, have been analyzed to investigate the optimum size of battery storage capacity for hybrid (PV + diesel) power systems. Various sizing configurations have been simulated. The monthly average daily values of solar global radiation range from 3.61 to 7.96kWh/m2. As a case study, hybrid systems considered in the present analysis consist of 225m2 PV array area (panels/modules) supplemented with battery storage unit and diesel backup generators (to meet the load requirements of a typical residential building with annual electrical energy demand of 35,200kWh). The monthly average energy generated from the aforementioned hybrid system for different scenarios has been presented. More importantly, the study explores the influence of variation of battery storage capacity on hybrid power generation. The results exhibit a trade-off between size of the storage capacity and diesel power to be generated to cope with annual load distribution. Concurrently, the energy to be generated from the diesel generator and the number of operational hours of the diesel system to meet the load demand have been also addressed.The study shows that for optimum operation of diesel system, storage capacity equivalent to 12 18h of maximum monthly average hourly demand need to be used. It has been found that in the absence of battery bank, ˜58% of the load needs to be provided by the diesel system. However, use of 12h of battery storage (autonomy) reduces diesel energy generation by ˜49% and the number of hours of operation of the diesel system get reduced by about ˜82%. The findings of this study can be employed as a tool for sizing of battery storage for PV/diesel systems for other regions having climates similar to the location considered in the study.

Shaahid, S. M.; Elhadidy, M. A.

2005-09-01

22

Stand-alone hybrid wind-photovoltaic power generation systems optimal sizing  

NASA Astrophysics Data System (ADS)

Wind and photovoltaic energy resources have attracted energy sectors to generate power on a large scale. A drawback, common to these options, is their unpredictable nature and dependence on day time and meteorological conditions. Fortunately, the problems caused by the variable nature of these resources can be partially overcome by integrating the two resources in proper combination, using the strengths of one source to overcome the weakness of the other. The hybrid systems that combine wind and solar generating units with battery backup can attenuate their individual fluctuations and can match with the power requirements of the beneficiaries. In order to efficiently and economically utilize the hybrid energy system, one optimum match design sizing method is necessary. In this way, literature offers a variety of methods for multi-objective optimal designing of hybrid wind/photovoltaic (WG/PV) generating systems, one of the last being genetic algorithms (GA) and particle swarm optimization (PSO). In this paper, mathematical models of hybrid WG/PV components and a short description of the last proposed multi-objective optimization algorithms are given.

Cr?ciunescu, Aurelian; Popescu, Claudia; Popescu, Mihai; Florea, Leonard Marin

2013-10-01

23

Hybrid renewable energy systems for power generation in stand-alone applications: A review  

Microsoft Academic Search

It has become imperative for the power and energy engineers to look out for the renewable energy sources such as sun, wind, geothermal, ocean and biomass as sustainable, cost-effective and environment friendly alternatives for conventional energy sources. However, the non-availability of these renewable energy resources all the time throughout the year has led to research in the area of hybrid

Prabodh Bajpai; Vaishalee Dash

2012-01-01

24

Review of the maximum power point tracking algorithms for stand-alone photovoltaic systems  

Microsoft Academic Search

A survey of the algorithms for seeking the maximum power point (MPP) is proposed. As has been shown, there are many ways of distinguishing and grouping methods that seek the MPP from a photovoltaic (PV) generator. However, in this article they are grouped as either direct or nondirect methods. The indirect methods (“quasi seeks”) have the particular feature that the

V. Salas; E. Olías; A. Barrado; A. Lázaro

2006-01-01

25

High-Performance Stand-Alone Photovoltaic Generation System  

Microsoft Academic Search

This study develops a high-performance stand-alone photovoltaic (PV) generation system. To make the PV generation system more flexible and expandable, the backstage power circuit is composed of a high step-up converter and a pulsewidth-modulation (PWM) inverter. In the dc-dc power conversion, the high step-up converter is introduced to improve the conversion efficiency in conventional boost converters to allow the parallel

Rong-Jong Wai; Wen-Hung Wang; Chung-You Lin

2008-01-01

26

Stand-alone photovoltaic generation system with combined storage using lead battery and EDLC  

Microsoft Academic Search

This research is mainly concerned with a stand-alone photovoltaic (PV) generation system for low power DC applications placed where the commercial AC grid connection is not supported. In this paper, basic and improved circuit topologies and the control schemes of stand-alone photovoltaic generation system are proposed. To prevent battery from deep discharge, electric double layer capacitor (EDLC) is incorporated into

Hiroaki Nakayama; Eiji Hiraki; Toshihiko Tanaka; Noriaki Koda; Nobuo Takahashi; Shuji Noda

2008-01-01

27

Modular photovoltaic stand-alone systems: Phase 1  

NASA Technical Reports Server (NTRS)

A family of modular stand-alone power systems that covered the range in power level from 1 kw to 14 kw was developed. Products within this family were required to be easily adaptable to different environments and applications, and were to be both reliable and cost effective. Additionally, true commonality in hardware was to be exploited, and unnecessary recurrence of design and development costs were to be minimized; thus improving hardware availability. Assurance of compatibility with large production runs, was also an underlying program goal. A secondary objective was to compile, evaluate, and determine the economic and technical status of available, and potentially available, technology options associated with the balance of systems (BOS) for stand-along photovoltaic (PV) power systems. The secondary objective not only directly supported the primary but additionally contributed to the definition and implementation of the BOS cost reduction plan.

Naff, G. J.; Marshall, N. A.

1983-01-01

28

Improve wind energy penetration in an isolated power system by a stand-alone wind pumped storage hydropower plant  

Microsoft Academic Search

As is well-known, using pumped storage system in a power system is one of ways to raise the wind energy penetration. In former studies, the introduction of pumped storage system in power production systems aims mainly at peak clipping, valley filling of a grid and so on. In the present study, a relatively novel solution is introduced to enable wind-hydro-pumped

Kun Qian; Yuxiang Jiang; Zheng Li

2011-01-01

29

Photovoltaic stand-alone modular systems, phase 2  

NASA Astrophysics Data System (ADS)

The final hardware and system qualification phase of a two part stand-alone photovoltaic (PV) system development is covered. The final design incorporated modular, power blocks capable of expanding incrementally from 320 watts to twenty kilowatts (PK). The basic power unit (PU) was nominally rated 1.28 kWp. The controls units, power collection buses and main lugs, electrical protection subsystems, power switching, and load management circuits are housed in a common control enclosure. Photo-voltaic modules are electrically connected in a horizontal daisy-chain method via Amp Solarlok plugs mating with compatible connectors installed on the back side of each photovoltaic module. A pair of channel rails accommodate the mounting of the modules into a frameless panel support structure. Foundations are of a unique planter (tub-like) configuration to allow for world-wide deployment without restriction as to types of soil. One battery string capable of supplying approximately 240 ampere hours nominal of carryover power is specified for each basic power unit. Load prioritization and shedding circuits are included to protect critical loads and selectively shed and defer lower priority or noncritical power demands. The baseline system, operating at approximately 2 1/2 PUs (3.2 kW pk.) was installed and deployed. Qualification was successfully complete in March 1983; since that time, the demonstration system has logged approximately 3000 hours of continuous operation under load without major incident.

Naff, G. J.; Marshall, N. A.

1983-07-01

30

Photovoltaic stand-alone modular systems, phase 2  

NASA Technical Reports Server (NTRS)

The final hardware and system qualification phase of a two part stand-alone photovoltaic (PV) system development is covered. The final design incorporated modular, power blocks capable of expanding incrementally from 320 watts to twenty kilowatts (PK). The basic power unit (PU) was nominally rated 1.28 kWp. The controls units, power collection buses and main lugs, electrical protection subsystems, power switching, and load management circuits are housed in a common control enclosure. Photo-voltaic modules are electrically connected in a horizontal daisy-chain method via Amp Solarlok plugs mating with compatible connectors installed on the back side of each photovoltaic module. A pair of channel rails accommodate the mounting of the modules into a frameless panel support structure. Foundations are of a unique planter (tub-like) configuration to allow for world-wide deployment without restriction as to types of soil. One battery string capable of supplying approximately 240 ampere hours nominal of carryover power is specified for each basic power unit. Load prioritization and shedding circuits are included to protect critical loads and selectively shed and defer lower priority or noncritical power demands. The baseline system, operating at approximately 2 1/2 PUs (3.2 kW pk.) was installed and deployed. Qualification was successfully complete in March 1983; since that time, the demonstration system has logged approximately 3000 hours of continuous operation under load without major incident.

Naff, G. J.; Marshall, N. A.

1983-01-01

31

Evaluation of a new maximum power point tracker (MPPT) applied to the photovoltaic stand-alone systems  

Microsoft Academic Search

In this paper a comparative study through experimental work between a new low-cost maximum power point tracker (MPPT) and the conventional configurations of the photovoltaic (PV) regulators under different atmospheric conditions is presented. The comparison is made by means of the energy production obtained by the PV generator of each system. From the results obtained it can be concluded that,

V. Salas; E. Olías; A. Lázaro; A. Barrado

2005-01-01

32

Sizing optimization and analysis of a stand-alone WTG system using hybrid energy storage technologies  

Microsoft Academic Search

Decentralized distributed generation technologies based on renewable energy recourses such as Solar PhotoVoltaic (SPV)\\/ Wind Turbine Generators (WTG) address the major issues concerned with conventional diesel generators to a large extent and are therefore considered as emerging alternate power solutions to stand alone applications. Three stand alone WTG power systems using different energy storage technologies, i.e. WTG-Battery system, WTG-Fuel Cell

Prabodh Bajpai; Sowjan Kumar; N. K. Kishore

2010-01-01

33

A stochastic method for stand-alone photovoltaic system sizing  

SciTech Connect

Photovoltaic systems utilize solar energy to generate electrical energy to meet load demands. Optimal sizing of these systems includes the characterization of solar radiation. Solar radiation at the Earth's surface has random characteristics and has been the focus of various academic studies. The objective of this study was to stochastically analyze parameters involved in the sizing of photovoltaic generators and develop a methodology for sizing of stand-alone photovoltaic systems. Energy storage for isolated systems and solar radiation were analyzed stochastically due to their random behavior. For the development of the methodology proposed stochastic analysis were studied including the Markov chain and beta probability density function. The obtained results were compared with those for sizing of stand-alone using from the Sandia method (deterministic), in which the stochastic model presented more reliable values. Both models present advantages and disadvantages; however, the stochastic one is more complex and provides more reliable and realistic results. (author)

Cabral, Claudia Valeria Tavora; Filho, Delly Oliveira; Martins, Jose Helvecio; Toledo, Olga Moraes [Department of Agricultural Engineering, Federal University of Vicosa, Av. P. H. Rolfs, s/n. 36570-000 Vicosa, Minas Gerais (Brazil); Diniz, Antonia Sonia Alves C.; Machado Neto, Lauro de Vilhena B. [Group of Studies in Energy - GREEN Solar, Pontifical Catholic University of Minas Gerais - PUC Minas, Rua Dom Jose Gaspar no. 500, Predio 03, Sala 218 - Coracao Eucaristico 30535-610 Belo Horizonte - Minas Gerais (Brazil)

2010-09-15

34

Sustainable energy planning based on a stand-alone hybrid renewableenergy\\/hydrogen power system: Application in Karpathos island, Greece  

Microsoft Academic Search

This study presents the sustainable planning of a renewables-based energy system, which aims to fulfil the electric needs of the island by replacing the existing diesel generators with new wind farms, photovoltaic installations and hydrogen production systems. Electric system design and least cost planning analysis were concluded using historic data from both demand and supply sides. An optimal “sustainable island”

G. P. Giatrakos; T. D. Tsoutsos; P. G. Mouchtaropoulos; G. D. Naxakis; G. Stavrakakis

2009-01-01

35

Study of a thermoelectric system equipped with a maximum power point tracker for stand-alone electric generation.  

NASA Astrophysics Data System (ADS)

According to the International Energy Agency, 1.4 billion people are without electricity in the poorest countries and 2.5 billion people rely on biomass to meet their energy needs for cooking in developing countries. The use of cooking stoves equipped with small thermoelectric generator to provide electricity for basic needs (LED, cell phone and radio charging device) is probably a solution for houses far from the power grid. The cost of connecting every house with a landline is a lot higher than dropping thermoelectric generator in each house. Thermoelectric generators have very low efficiency but for isolated houses, they might become really competitive. Our laboratory works in collaboration with plane`te-bois (a non governmental organization) which has developed energy-efficient multifunction (cooking and hot water) stoves based on traditional stoves designs. A prototype of a thermoelectric generator (Bismuth Telluride) has been designed to convert a small part of the energy heating the sanitary water into electricity. This generator can produce up to 10 watts on an adapted load. Storing this energy in a battery is necessary as the cooking stove only works a few hours each day. As the working point of the stove varies a lot during the use it is also necessary to regulate the electrical power. An electric DC DC converter has been developed with a maximum power point tracker (MPPT) in order to have a good efficiency of the electronic part of the thermoelectric generator. The theoretical efficiency of the MMPT converter is discussed. First results obtained with a hot gas generator simulating the exhaust of the combustion chamber of a cooking stove are presented in the paper.

Favarel, C.; Champier, D.; Bédécarrats, J. P.; Kousksou, T.; Strub, F.

2012-06-01

36

Modular stand-alone monitor and control system (SAMAC)  

SciTech Connect

Large high energy physics experiments require constant monitoring and control of the numerous components of the particle detector apparatus. This paper describes a basic hardware configuration which has been designed to satisfy the monitoring and control requirements of the many different experimental setups. The system is designed to operate in the stand-alone mode, and may be interfaced to a host computer via CAMAC. The entire system is modular so that it can be easily tailored to an individual experiment. The items monitored and/or controlled may include gas pressures, temperatures, magnetic fields, high and low voltages, and system status or safety information.

Kieffer, J.

1980-10-01

37

A battery ageing model used in stand alone PV systems  

NASA Astrophysics Data System (ADS)

The authors present a new model for the ageing of a lead-acid battery which is based on the initial model of Shepherd. The proposed model allows to predict temporal variations of the Shepherd coefficients and to control the deterioration of the battery parameters and performances. The model validation has been realised by the recursive least square (RLS) algorithm by using long-term measurements under several solicitations. This study will improve the storage section of stand-alone photovoltaic systems and reduce overloads and deep discharges.

Cherif, A.; Jraidi, M.; Dhouib, A.

38

A Markovian Approach to Size a Hybrid Wind-Diesel Stand Alone System  

Microsoft Academic Search

A Markovian approach already developed in a previous paper by some of the authors to evaluate the energy production and power availability of a wind turbine is utilized to size a hybrid wind-diesel stand alone system. The wind turbine power time variability is taken into account by means of a discrete reduced number of contiguous power classes, each corresponding to

V. Carpentiero; R. Langella; T. Manco; A. Testa

2008-01-01

39

US manufacturers of commercially available stand-alone photovoltaic lighting systems  

SciTech Connect

This report introduces photovoltaic (PV) lighting systems, gives some specifications for ordering these systems, and provides a list of some of the manufacturers of these systems in the United States. These PV lighting systems are all commercially available. They are stand-alone systems because they are not tied to the electric utility power grid.

McNutt, P.

1994-05-01

40

Photovoltaic Module Simulink Model for a Stand-alone PV System  

NASA Astrophysics Data System (ADS)

Photovoltaic(PV) Module is indispensable of a stand-alone PV system. In this paper, a one-diode equivalent circuit-based versatile simulation model in the form of masked block PV module is proposed. By the model, it is allowed to estimate behavior of PV module with respect changes on irradiance intensity, ambient temperature and parameters of the PV module. In addition, the model is capable of function of Maximum Power Point Tracking (MPPT) which can be used in the dynamic simulation of stand-alone PV systems.

Qi, Chen; Ming, Zhu

41

GPGS: a device-independent general purpose graphic system for stand-alone and satellite graphics  

Microsoft Academic Search

GPGS is a subroutine package offering powerful and versatile support for passive and interactive vector graphics, for time-sharing, batch, and stand-alone minicomputer systems. The package is computer, language, and operating system, as well as display device independent. Its key purpose is to allow for transportabiliit of programs and programmers by providing easy to learn, high level features. The applications programmer

L. C. Caruthers; J. Van Den Bos; A. Van Dam

1977-01-01

42

Simulation model for sizing of stand-alone solar PV system with interconnected array  

Microsoft Academic Search

Solar PV arrays made of interconnected modules are comparatively less susceptible to shadow problem and power degradation resulting from the aging of solar cells. This paper presents a simulation model for the sizing of stand-alone solar PV systems with interconnected arrays. It considers the electricity generation in the array and its storage in the battery bank serving the fluctuating load

N. D. Kaushika; Nalin K. Gautam; Kshitiz Kaushik

2005-01-01

43

Stand-alone and network capable pocket radiation detection system  

NASA Astrophysics Data System (ADS)

A multi-functional and networked pocket radiation detection system has been developed at the Idaho National Laboratory (INL) capable of detecting and storing gamma ray and neutron data. The device can be used as a stand-alone device or in conjunction with an array to cover a small or large area. The device has programmable alarm trigger levels that can be modified for specific applications. The data are stored with a date/time stamp and can be transferred and viewed on a PDA via direct connection or, in networked configuration, wireless connection to a remote central facility upon request. Data functional/bench tests have been completed successfully and the device was demonstrated to detect radiation from a 55.6 ?Ci 252Cf source at 5 m and from 1.4 mCi 252Cf source at 10 m which exceeds both ANSI and IAEA standards for pocket radiation detection. In terms of sensitivity, this detection system detects neutron and gamma-ray fields down to 10 ?rem/h levels and therefore can find the location of the radioactive source quickly. The detection system is small enough to be put in a pocket or clipped to a belt.

Aryaeinejad, R.; Spencer, D. F.

2009-03-01

44

EXPERIMENTAL EVALUATION OF AN ANALYTIC METHOD FOR SIZING STAND-ALONE PV SYSTEMS  

Microsoft Academic Search

The performance of a stand-alone PV system depends on the behavior of each component and on the solar radiation, size of PV-array and storage capacity. Therefore, the correct sizing plays an important role on the reliability of the stand-alone PV systems. The purpose of this paper is to present the experimental evaluation of an analytic method for sizing stand-alone systems

I. Zanesco; A. Moehlecke; G. S. Medeiros; T. C. Severo; D. Eberhardt

45

Pre-feasibility study of stand-alone hybrid energy systems for applications in Newfoundland  

Microsoft Academic Search

A potential solution for stand-alone power generation is to use a hybrid energy system in parallel with some hydrogen energy storage. In this paper, a pre-feasibility study of using hybrid energy systems with hydrogen as an energy carrier for applications in Newfoundland, Canada is explained. Various renewable and non-renewable energy sources, energy storage methods and their applicability in terms of

M. J. Khan; M. T. Iqbal

2005-01-01

46

Stand-alone photovoltaic (PV) powered electrochromic window  

DOEpatents

A variable transmittance double pane window includes an electrochromic material that has been deposited on one pane of the window in conjunction with an array of photovoltaic cells deposited along an edge of the pane to produce the required electric power necessary to vary the effective transmittance of the window. A battery is placed in a parallel fashion to the array of photovoltaic cells to allow the user the ability to manually override the system when a desired transmittance is desired.

Benson, David K. (Golden, CO); Crandall, Richard S. (Boulder, CO); Deb, Satyendra K. (Boulder, CO); Stone, Jack L. (Lakewood, CO)

1995-01-01

47

Stand-alone photovoltaic (PV) powered electrochromic window  

DOEpatents

A variable transmittance double pane window includes an electrochromic material that has been deposited on one pane of the window in conjunction with an array of photovoltaic cells deposited along an edge of the pane to produce the required electric power necessary to vary the effective transmittance of the window. A battery is placed in a parallel fashion to the array of photovoltaic cells to allow the user the ability to manually override the system when a desired transmittance is desired. 11 figures.

Benson, D.K.; Crandall, R.S.; Deb, S.K.; Stone, J.L.

1995-01-24

48

Optimal energy management of a photovoltaic stand-alone dual battery system  

Microsoft Academic Search

The paper introduces a new optimal energy management method for photovoltaic stand-alone dual battery systems. The method exploits a predictive state of charge (SOC) model to implement the control algorithm. To validate the proposed algorithm a stand-alone photovoltaic system has been modeled. Finally, Monte Carlo simulations based on a probabilistic model of the solar radiation have been performed. The results

G. Barca; A. Moschetto; C. Sapuppo; G. M. Tina; R. Giusto; A. D. Grasso

2008-01-01

49

Power quality improvement in stand-alone microgrid including fixed-speed wind farm: Role of dynamic voltage restorer  

Microsoft Academic Search

According to the growth of power generated by wind farms and the increased number of non-linear loads, providing a high quality electrical power, should be considered. This paper is addressed the issue of application and analysis of a Dynamic Voltage Restorer (DVR) to enhance the quality of power flows in a stand-alone microgrid, including wind energy conversion systems and the

Ahmad Jamshidi; Mohammad Moradi Ghahderijani; S. Masoud Barakati

2012-01-01

50

An approach to evaluate the general performance of stand-alone wind\\/photovoltaic generating systems  

Microsoft Academic Search

This paper reports the development of a computer approach for evaluating the general performance of stand-alone wind\\/photovoltaic generating systems. Simple models for different system components are developed, integrated, and used to predict the behavior of generating systems based on available wind\\/solar and load data. The model is useful for evaluating the performance of stand-alone generating systems and gaining a better

M. Hashem Nehrir; Brock J. LaMeres; Giri Venkataramanan; Victor Gerez; L. A. Alvarado

2000-01-01

51

Life cycle cost analysis of a stand-alone PV system in rural Kenya  

NASA Astrophysics Data System (ADS)

The purpose of this quantitative research study was to determine the economic feasibility of a stand-alone PV system to electrify a rural area in Kenya. The research conducted involved a comprehensive review of all the relevant literature associated with the study. Methodologies were extrapolated from this extensive literature to develop a model for the complete design and economic analysis of a stand-alone PV system. A women's center in rural Kenya was used as a worked example to demonstrate the workings of the model. The results suggest that electrifying the center using a stand-alone PV system is an economically viable option which is encouraging for the surrounding area. This model can be used as a business model to determine the economic feasibility of a stand-alone PV system in alternative sites in Kenya.

Daly, Emma

52

Status of DOE and AID stand-alone photovoltaic system field tests  

NASA Technical Reports Server (NTRS)

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

1984-01-01

53

Techno-economic analysis and modelling of stand-alone versus grid-connected small hydro-power systems – a review of literature  

Microsoft Academic Search

Hydro-energy has been universally accepted as the most reliable and cost-effective renewable energy source. Among the several types of hydro-power-generation methods, small hydro-power (SHP) system plays a major role in meeting power requirements of remote, isolated hilly areas in a de-centralized manner by tapping water streams, rivulets and canals of small discharge. An SHP system can function either connected with

P. P. Sharma; S. Chatterji; Balwinder Singh

2011-01-01

54

Dynamic response of a stand-alone wind energy conversion system with battery energy storage to a wind gust  

Microsoft Academic Search

A mathematical model of each element of a stand-alone wind energy conversion system is developed. The model variables are expressed in the d-q rotor reference frame. The wind turbine was considered as the only source of power in this study. Using this model, the system response to a recorded wind gust is investigated by calculating the generator current, the rectifier

Bogdan S. Borowy; Ziyad M. Salameh

1997-01-01

55

A stochastic method for stand-alone photovoltaic system sizing  

Microsoft Academic Search

Photovoltaic systems utilize solar energy to generate electrical energy to meet load demands. Optimal sizing of these systems includes the characterization of solar radiation. Solar radiation at the Earth’s surface has random characteristics and has been the focus of various academic studies. The objective of this study was to stochastically analyze parameters involved in the sizing of photovoltaic generators and

Claudia Valéria Távora Cabral; Delly Oliveira Filho; Antônia Sônia Alves C. Diniz; José Helvecio Martins; Olga Moraes Toledo; Lauro de Vilhena B. Machado Neto

2010-01-01

56

A stochastic method for stand-alone photovoltaic system sizing  

Microsoft Academic Search

Photovoltaic systems utilize solar energy to generate electrical energy to meet load demands. Optimal sizing of these systems includes the characterization of solar radiation. Solar radiation at the Earth's surface has random characteristics and has been the focus of various academic studies. The objective of this study was to stochastically analyze parameters involved in the sizing of photovoltaic generators and

Claudia Valeria Tavora Cabral; Delly Oliveira Filho; Jose Helvecio Martins; Olga Moraes Toledo; Antonia Sonia Alves C. Diniz; Lauro de Vilhena B. Machado Neto

2010-01-01

57

A Current Sensorless MPPT Control Method for a Stand-Alone-Type PV Generation System  

NASA Astrophysics Data System (ADS)

In this paper, a current sensorless MPPT control method for a stand-alone-type PV generation system is proposed. This control method offers advantages of the simplified hardware configuration and the low cost, by using only one sensor to measure the PV output voltage. In the application to stand-alone-type with a battery load, the experimental results show that the estimated values of PV output current are accurate, and the use of the proposed MPPT control increases the PV generated energy by 16.3% compared to the conventional system. Furthermore, it is clarified that the proposed method has extremely high UUF (Useful utilization factor) of 98.7%.

Itako, Kazutaka; Mori, Takeaki

58

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

Microsoft Academic Search

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

R. Posadillo; R. López Luque

2008-01-01

59

Techno-economical analysis of Vanadium redox and Lead-acid batteries in stand-alone photovoltaic systems  

Microsoft Academic Search

Sizing and techno-economical analysis of a stand-alone photovoltaic generation system with different energy storage is presented in this paper. The method adopted is based on the Loss of power supply probability and levelized cost of energy concepts. A new energy storage technology of Vanadium redox battery was applied in photovoltaic power system, which was compared to traditional Lead-acid battery from

Guozhen Hu; Shanxu Duan; Cai tao; Changsong Chen

2010-01-01

60

Research on BiDirectional DC-DC Converter For a Stand-Alone Photovoltaic Hybrid Energy Storage System  

Microsoft Academic Search

A novel stand-alone photovoltaic ultracapacitor\\/battery hybrid energy storage system is proposed. Compared with the traditional one, this system has high power density and high energy density, prolong the lifetime of battery, achieve the system more efficient and reliable etc. A digital control system for multiple-input bi-directional dc-dc converter is designed and implemented. Software and hardware implementation issuses are described .

Xie Jun; Zhang Xing; Zhang Chongwei; Wang Chengyue

2010-01-01

61

Implementation of a Stand-Alone Photovoltaic Lighting System with MPPT, Battery Charger and High Brightness LEDs  

Microsoft Academic Search

This paper presents a high-efficiency stand-alone photovoltaic (PV) lighting system which can provide functional illumination based on high-brightness light-emitting diodes (HBLEDs). HBLED with specific features of small size, long life and low power consumption will be choices of future light sources. In order to provide a steady-state operating environment for HBLEDs, a specially designed lighting power module is implemented. Maximum

Chih-Chiang Hua; Pi-Kuang Ku

2005-01-01

62

Effective voltage and frequency control strategy for a stand-alone system with induction generator\\/fuel cell\\/ultracapacitor  

Microsoft Academic Search

This paper proposes the control scheme for an AC-linked hybrid wind\\/fuel cell\\/ultracapacitor alternative energy system for a stand-alone operation. Due to the intermittent nature of power obtained from the wind turbine-generator system, Hydrogen\\/fuelcell(H2\\/FC) and ultracapacitor(UC)are introduced as main storage and buffer storage respectively, to supply the demand for all operating conditions. Fuelcell, by virtue of its inherent slow generator dynamics,

Netra GYAWALI; Yasuharu OHSAWA

2009-01-01

63

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

PubMed

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. PMID:15887634

2005-03-01

64

Implementation of a stand-alone photovoltaic lighting system with MPPT battery charging and LED current control  

Microsoft Academic Search

This paper presents a efficient stand-alone battery photovoltaic (PV) lighting system which can provide functional illumination based on power light-emitting diodes (PLEDs). PLED with specific features of small size, long life and high-brightness light will be choices of future light sources. The PLEDs are feed using a lead acid battery that is charged with a PV panel. This paper presents

José António Barros Vieira; Alexandre Manuel Mota

2010-01-01

65

A probabilistic method for the evaluation of the reliability of stand alone wind energy systems  

SciTech Connect

This paper describes a probabilistic method for the computation of the loss of load probability (LOLP) and the expected unserved energy (EUE) of a stand alone wind energy system. The system consists of a wind generator and a storage battery supplying the consumer load. The statistics of the surplus generation (excess wind generation over load demand) time series are computed and used for the calculation of the desired reliability indices. It is shown that, in the probability computations, the serial correlation of the surplus generation cannot be ignored. The performance of the developed method is demonstrated with computational results. Some results useful for the design of stand alone wind energy systems are also presented.

Bakirtzis, A.G. (Aristotelian Univ. of Thessaloniki (GR))

1992-03-01

66

Space crew radiation exposure analysis system based on a commercial stand-alone CAD system  

NASA Technical Reports Server (NTRS)

Major improvements have recently been completed in the approach to spacecraft shielding analysis. A Computer-Aided Design (CAD)-based system has been developed for determining the shielding provided to any point within or external to the spacecraft. Shielding analysis is performed using a commercially available stand-alone CAD system and a customized ray-tracing subroutine contained within a standard engineering modeling software package. This improved shielding analysis technique has been used in several vehicle design projects such as a Mars transfer habitat, pressurized lunar rover, and the redesigned Space Station. Results of these analyses are provided to demonstrate the applicability and versatility of the system.

Appleby, Matthew H.; Golightly, Michael J.; Hardy, Alva C.

1992-01-01

67

Space crew radiation exposure analysis system based on a commercial stand-alone CAD system  

NASA Astrophysics Data System (ADS)

Major improvements have recently been completed in the approach to spacecraft shielding analysis. A Computer-Aided Design (CAD)-based system has been developed for determining the shielding provided to any point within or external to the spacecraft. Shielding analysis is performed using a commercially available stand-alone CAD system and a customized ray-tracing subroutine contained within a standard engineering modeling software package. This improved shielding analysis technique has been used in several vehicle design projects such as a Mars transfer habitat, pressurized lunar rover, and the redesigned Space Station. Results of these analyses are provided to demonstrate the applicability and versatility of the system.

Appleby, Matthew H.; Golightly, Michael J.; Hardy, Alva C.

1992-07-01

68

Energy Management System with Stability Constraints for Stand-alone Autonomous Microgrid  

Microsoft Academic Search

This paper presents an energy management system (EMS) for a stand-alone droop-controlled microgrid, which adjusts generator outputs to minimize fuel consumption and also ensures stable operation. It has previously been shown that droop gains have a significant effect on stability in such microgrids. Approximate relationships between these parameters and stability margins are therefore identified, using qualitative analysis and small-signal techniques.

E. Barklund; N. Pogaku; M. Prodanovic; C. Hernandez-Aramburo; T. C. Green

2007-01-01

69

System Simulation by Recursive Feedback: Coupling A Set of Stand-Alone Subsystem Simulations  

NASA Technical Reports Server (NTRS)

Recursive feedback is defined and discussed as a framework for development of specific algorithms and procedures that propagate the time-domain solution for a dynamical system simulation consisting of multiple numerically coupled self-contained stand-alone subsystem simulations. A satellite motion example containing three subsystems (other dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Centralized and distributed versions of coupling structure have been addressed. Numerical results are evaluated by direct comparison with a standard total-system simultaneous-solution approach.

Nixon, Douglas D.; Hanson, John M. (Technical Monitor)

2002-01-01

70

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

NASA Technical Reports Server (NTRS)

Recursive feedback is defined and discussed as a framework for development of specific algorithms and procedures that propagate the time-domain solution for a dynamical system simulation consisting of multiple numerically coupled, self-contained, stand-alone 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. Centralized and distributed versions of coupling structure have been addressed. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

Nixon, Douglas D.; Ryan, Stephen G. (Technical Monitor)

2002-01-01

71

Dynamic response of a stand-alone wind energy conversion system with battery energy storage to a wind gust  

SciTech Connect

A mathematical model of each element of the Stand-Alone Wind Energy Conversion System is developed. The model variables are expressed in the d-q rotor reference frame. The wind turbine was considered as the only source of power in this study. Using this model the system response to a recorded wind gust is investigated by calculating the generator current, the rectifier current, the load current, the battery charging current, and the battery voltage. The calculated results are then verified by comparing them with the actual values obtained from the data acquisition system. A good agreement was achieved between the experimental and the analytical results.

Borowy, B.S.; Salameh, Z.M. [Univ. of Massachusetts, Lowell, MA (United States). Dept. of Electrical Engineering] [Univ. of Massachusetts, Lowell, MA (United States). Dept. of Electrical Engineering

1997-03-01

72

Battery and charge controller evaluations in small stand-alone PV systems  

SciTech Connect

We report the results of to separate long-term tests of batteries and charge controllers in small stand-alone PV systems. In these experiments, seven complete systems were tested for two years at each of two locations: Sandia National Laboratories in Albuquerque and the Florida Solar Energy Center in Cape Canaveral, Florida. Each system contained a PV array, flooded-lead-acid battery, a charge controller and a resistive load. Performance of the systems was strongly influenced by the difference in solar irradiance at the two sites, with some batteries at Sandia exceeding manufacturer`s predictions for cycle life. System performance was strongly correlated with regulation reconnect voltage (R{sup 2} correlation coefficient = 0.95) but only weakly correlated with regulation voltage. We will also discuss details of system performance, battery lifetime and battery water consumption.

Woodworth, J.R.; Thomas, M.G.; Stevens, J.W. [Sandia National Labs., Albuquerque, NM (United States); Dunlop, J.L.; Swamy, M.R.; Demetrius, L. [Florida Solar Energy Center, Cape Canaveral, FL (United States); Harrington, S.R. [K-Tech Corp., Albuquerque, NM (United States)

1994-07-01

73

Stand-alone digital data storage control system including user control interface  

NASA Technical Reports Server (NTRS)

A storage control system includes an apparatus and method for user control of a storage interface to operate a storage medium to store data obtained by a real-time data acquisition system. Digital data received in serial format from the data acquisition system is first converted to a parallel format and then provided to the storage interface. The operation of the storage interface is controlled in accordance with instructions based on user control input from a user. Also, a user status output is displayed in accordance with storage data obtained from the storage interface. By allowing the user to control and monitor the operation of the storage interface, a stand-alone, user-controllable data storage system is provided for storing the digital data obtained by a real-time data acquisition system.

Wright, Kenneth D. (Inventor); Gray, David L. (Inventor)

1994-01-01

74

An overview of renewable energy technologies with a view to stand alone power generation and water provision  

Microsoft Academic Search

A brief overview is provided of renewable energy technologies suited to stand alone power generation; in practice this means wind turbines and photovoltaics (PV) as these can be used in diverse locations, and to a lesser extent micro-hydro which is more site specific and bio-energy although this last one may not be effective at the smaller scales mostly involved. The

D. G. Infield

2009-01-01

75

Stand alone computer system to aid the development of Mirror Fusion Test Facility rf heating systems  

SciTech Connect

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.

Thomas, R.A.

1983-12-01

76

Study on soft phase locked method to solving the synchronization problem of active power filter in stand-alone power grid  

Microsoft Academic Search

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, the influence of the synchronizing signal error on current detection of APF is

Zhuo Fang; Wu Longhui; Chen Zhe; Wang Xianwei; Wang Zhaoan

2009-01-01

77

Cogging torque reduction in Dual-Rotor Permanent Magnet Generator for Direct Coupled Stand-Alone Wind Energy Systems  

Microsoft Academic Search

In a permanent magnet machine cogging torque is produced due to the interaction between the rotor magnets and the slots and teeth of the stator. This paper is a result of an ongoing research work that deals with reduction of cogging torque in dual-rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand-alone wind energy systems. The DRFPMG is

P. Sivachandran; P. Venkatesh; N. Kamaraj

2008-01-01

78

Reliability analysis of a stand-alone PV system for the supply of a remote electric load  

Microsoft Academic Search

The work presents a reliability analysis of a stand-alone photovoltaic system for the supply of electric loads located in remote areas not easily reachable by the low voltage distribution network. The analysis is performed by characterizing the electric load behavior by means of a Montecarlo approach for taking into account the stochastic variability of the electrical energy demand. A Montecarlo

A. Campoccia; S. Favuzza; E. Riva Sanseverino; G. Zizzo

2010-01-01

79

Output Power Maximization of a Permanent Magnet Synchronous Generator Based Stand-alone Wind Turbine  

Microsoft Academic Search

This paper proposes output power maximization control of wind energy system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed wind energy system. In order to achieve the maximum power control of wind turbine across a wide range of wind speeds, a dynamic modeling and simulation of wind system with battery energy storage

T. Tafticht; K. Agbossou; A. Cheriti; M. L. Doumbia

2006-01-01

80

A stand-alone demography and landscape structure module for Earth system models  

NASA Astrophysics Data System (ADS)

We propose and demonstrate a new approach for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any earth system model (Haverd et al., 2013). The approach is encoded in a model called Populations-Order-Physiology (POP). We demonstrate the behaviour and performance of POP coupled to the Community Atmosphere Biosphere Land Exchange model (CABLE) for two contrasting applications: (i) to the Northern Australian Tropical Transect, featuring gradients in savanna vegetation cover, rainfall and fire disturbance and (ii) to a set of globally distributed forest locations coinciding with observations of forest biomass allometry. Along the Northern Australian Tropical Transect, CABLE-POP is able to simultaneously reproduce observation-based estimates of key functional and structural variables, namely gross primary production, tree foliage projective cover, basal area and maximum tree height. This application particularly demonstrates the ability of POP to quantify the contributions of drought and fire to tree mortality. Drought is manifested as an increase in mortality due to a decline in growth efficiency, while fires are treated as partial disturbance events, with tree mortality depending on tree size and fire intensity. In the application to global forests, POP is integrated with global forest data by calibrating it against paired observations of stem biomass and number density. The calibrated POP model is then coupled with CABLE and the coupled model is evaluated against leaf-stem allometry observations from forest stands ranging in age from 20 to 400 years. Results indicate that, in contrast to simulations from many global land surface models (Wolf et al., 2011), simulated biomass pools conform well with observed allometry. We conclude that POP, which can readily be coupled to the terrestrial carbon cycle component of any LSM, represents a significant advance in our ability to use in-situ and remotely sensed observations of biomass and individual level parameters (e.g. crown-size, tree-height, stem diameter) as constraints on the terrestrial carbon cycle. Haverd, V., B. Smith, G. Cook, P. Briggs, L. Nieradzik, S. Roxburgh, A. Liedloff, C. Meyer, and J. G. Canadell, A stand-alone tree demography and landscape structure module for Earth system models, submitted to Geophys. Res. Let., 2013 Wolf, A., P. Ciais, V. Bellassen, N. Delbart, C.B. Field, and J.A. Berry, Forest biomass allometry in global land surface models, Global Biogeochem. Cycles, 25, GB3015, doi:10.1029/2010GB003917, 2011

Nieradzik, L. P.; Haverd, V.; Smith, B.; Cook, G. D.; Briggs, P.; Roxburgh, S.; Liedloff, A.; Meyer, C.; Canadell, J.

2013-12-01

81

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

National Technical Information Service (NTIS)

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 ...

M. G. Lee J. S. Song B. Kim Park M. W. Jung

1995-01-01

82

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

Microsoft Academic Search

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

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

2009-01-01

83

A simplified propeller turbine runner design for stand alone micro-hydro power generation units  

Microsoft Academic Search

In most developing countries, the vast majority of potential micro-hydro power generation sites, i.e. with power outputs up to 100kW, are found in areas with high rainfall or extensive irrigation works with small canal drops. These sites, where the available head does not exceed 5m, are usually referred to as low head sites. The present paper introduces a simplified design

G. M. Demetriades; A. A. Williams; N. P. A. Smith

1996-01-01

84

Stand-Alone Front-End System for High-Frequency, High-Frame-Rate Coded Excitation Ultrasonic Imaging  

PubMed Central

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 Vpp. 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 (LiNbO3) single-element lightweight (<0.28 g) transducers were utilized. The wire target measurement 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.

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

2012-01-01

85

Design and construction of a stand-alone camera system and its clinical application in nuclear medicine.  

PubMed

This paper reports investigations into some of the improvements of the performance of 'modular' gamma-ray cameras. Each modular camera has a 10 x 10 cm NaI(Tl) scintillation crystal and four 5 x 5 cm photomultiplier tubes (PMTs). When the gamma-ray photons interact with the crystal, scintillation flashes are emitted from the crystal and detected by the PMTs. The PMTs then convert the light flashes to current pulses. A digital computing circuitry processes the PMT outputs and assigns an estimated (x, y) coordinate corresponding to the location of interaction of each gamma-ray photon in the crystal and thus an image is formed. This paper is concerned with improvements and clinical applications of the modular cameras. We do the camera characterization by measuring spatial resolution and sensitivity of the modular camera and compare these characteristics to those of a commercial gamma camera. We design and construct a stand-alone planar imaging system based on the modular camera. This imager is examined with a set of phantoms and clinical tests to demonstrate the clinical feasibility of the stand-alone system. PMID:10214712

Chen, J C

1999-05-01

86

Supervisor control for a stand-alone hybrid generation system using wind and photovoltaic energy  

Microsoft Academic Search

A comprehensive supervisor control for a hybrid system that comprises wind and photovoltaic generation subsystems, a battery bank, and an ac load is developed in this paper. The objectives of the supervisor control are, primarily, to satisfy the load power demand and, second, to maintain the state of charge of the battery bank to prevent blackout and to extend the

Fernando Valenciaga; Paul F. Puleston

2005-01-01

87

Flicker contribution of a wind turbine in a stand-alone wind diesel system  

Microsoft Academic Search

To study the impact of aeroelastic aspects of a wind turbine (i.e. tower shadow, wind shear, turbulence, and mechanical vibrations) on the power quality of a wind-diesel system all electrical, mechanical and aerodynamic aspects of the wind turbine must be studied. Moreover, the contribution of the diesel-generator system and its controllers should be considered. This paper, describes how the aerodynamic

Roohollah Fadaeinedjad; Gerry Moschopoulos; Mehrdad Moallem

2008-01-01

88

Integrating Fuel Cell\\/Electrolyzer\\/Ultracapacitor System Into a Stand-Alone Microhydro Plant  

Microsoft Academic Search

This paper explores the control and operational aspects of introducing fuel cell\\/electrolyzer\\/ultracapacitor (FC\\/ELZ\\/UC) unit into a microhydro power system, replacing the conventional electronic load controller\\/dump-load unit. FC\\/ELZ is expected to provide long-term energy balance by utilizing the hydrogen technology, whereas the UC is employed as buffer storage for the transient compensation. System configuration is proposed, control scheme is designed, and

Netra Gyawali; Yasuharu Ohsawa

2010-01-01

89

Stand Alone Computer System to Aid the Development of Mirror Fusion Test Facility RF Heating Systems.  

National Technical Information Service (NTIS)

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 co...

R. A. Thomas

1983-01-01

90

A new power stabilization control system based on making use of mechanical inertia of a variable-speed wind-turbine for stand-alone wind-diesel applications  

Microsoft Academic Search

In this paper is described the development of a new wind-diesel generator system which is based on standard diesel generators connected to MADE AE-56 wind turbines. Such wind-turbines have variable-speed, variable-pitch operation and they are regulated under a special patented control algorithm, devoted to stabilization of grid frequency. One of the most important advantages deduced from the behaviour of the

S. Hurtado; G. Gostales; A. de Lara; N. Moreno; J. M. Carrasco; E. Galvan; J. A. Sanchez; L. G. Franquelo

2002-01-01

91

Optimal design of energy storage systems for stand-alone hybrid wind\\/PV generators  

Microsoft Academic Search

A major shortcoming in the exploitation of renewable energy sources relies in the effective power availability, that depends from the variability of the primary energy resource over the time. Because of the variability and unpredictability of primary power both photovoltaic arrays and wind turbines cannot ensure the minimum level of power continuity required to supply in island mode a generic

A. Testa; S. De Caro; R. La Torre; T. Scimone

2010-01-01

92

A novel MPPT charge regulator for a photovoltaic stand-alone telecommunication system  

Microsoft Academic Search

An improved MPPT (Maximum Power Point Tracking) algorithm charge controller exploiting an interleaved synchronous buck converter has been designed and realized to extract the maximum power from a photovoltaic panel. The converter sends the available photovoltaic energy to a battery pack thanks to an input control loop that reads the input voltage and limits the output current of the converter,

G. Barca; A. Moschetto; C. Sapuppo; G. M. Tina; R. Giusto; A. D. Grasso

2008-01-01

93

New Stand-Alone and Advanced Earthquake Early Warning Systems Designed to Protect Railways  

Microsoft Academic Search

A new earthquake detection and warning system that uses single station records was designed. The system determines the location and magnitude of an earthquake and issues an alarm immediately after arrival of the P wave (primary wave or longitudinal waves). In the conventional system now in use with Shinkansen (“bullet”) trains, magnitude is first determined and then distance is evaluated.

Toshikazu Odaka; Kimitoshi Ashiya; Shin'ya Tsukada; Toru Miyauchi

2006-01-01

94

NASA preprototype redox storage system for a photovoltaic stand-alone application  

NASA Technical Reports Server (NTRS)

A 1 kW preprototype redox storage system underwent characterization tests and was operated as the storage device for a 5 kW (peak) photovoltaic array. The system is described and performance data are presented. Loss mechanisms are discussed and simple design changes leading to significant increases in efficiency are suggested. The effects on system performance of nonequilibrium between the predominant species of complexed chromic ion in the negative electrode reactant solution are indicated.

Hagedorn, N. H.

1981-01-01

95

5 Wp PV module-based stand-alone solar tracking system  

Microsoft Academic Search

5 Watt-PV module is utilized for tracking solar oven concentrator system with 2.6 kW\\/sub th\\/ capacity and 200 Kg weight. The tracking system follows the sun autonomously in altitude and azimuth using only 5 Watt-peak PV solar module as a tracking energy source. The tracking system is driven by means of two 12 DCV motors of 36 W each, and

J. A. Urbano; Y. Matsumoto; R. Asomoza; F. J. Aceves; A. Sotelo; A. Jacome

2003-01-01

96

Data acquisition system of the NANOSAW-2 stand alone wind diesel plant. Document and user's guide  

NASA Astrophysics Data System (ADS)

This document is the report of a wind-diesel measurement and modeling project. A measurement system comprising signal transducers, wiring, data logger, and data acquisition software has been constructed. The system produces comprehensive data of high quality. Remote control of measurement system and monitoring of plant status is also possible. The selected data logging unit has proved to be reliable. The logger and software can also be applied to other data acquisition applications with minor changes. Chapters 2 and 3 describe the physical measurement system excluding the data logger. The data acquisition including the hardware (data logger) and the software are discussed in chapter 4. Chapter 5 contains the user instructions.

Manninen, L. M.

1993-12-01

97

Feasibility Study of Stand-Alone PV-Wind-Biomass Hybrid Energy System in Australia  

Microsoft Academic Search

This paper presents a feasibility study of photo- voltaic (PV), wind, biomass and battery storage based hybrid renewable energy (HRE) system providing electricity to residen- tial area in Australia. The system with load of 200 kWh·day ?1 is analyzed through the environmental and economic aspects. The study computes the net present cost (NPC, $), cost of energy (COE, $ ·

Gang Liu; M. G. Rasul; M. T. O. Amanullah; M. M. K. Khan

2011-01-01

98

An advanced SOC model for a stand-alone telecommunication system  

Microsoft Academic Search

This paper reports on a new online lead-acid battery state of charge (SOC) monitoring system for both the discharge and charge periods. The proposed SOC monitoring system is based on both a mathematical model and static charge\\/discharge characteristics at various current rates. Experimental results confirming the validity of the model are also reported.

G. Barca; A. Moschetto; C. Sapuppo; G. M. Tina; R. Giusto; A. D. Grasso

2008-01-01

99

Design of a multilevel control strategy for integration of stand-alone wind\\/diesel system  

Microsoft Academic Search

Control of variable speed wind turbines coupled with squirrel cage induction generators situated in remote areas is difficult and suffers from some fundamental problems. These systems cannot stabilize frequency and voltage of the grid in acceptable ranges. Changes in the load during 1 day and sudden changes in wind speed also make this problem harder to deal with. In this

B. Sedaghat; A. Jalilvand; R. Noroozian

100

A stand-alone tree demography and landscape structure module for Earth system models  

NASA Astrophysics Data System (ADS)

propose and demonstrate a new approach for the simulation of woody ecosystem stand dynamics, demography, and disturbance-mediated heterogeneity suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any earth system model. The approach is encoded in a model called Populations-Order-Physiology (POP). We demonstrate the behavior and performance of POP coupled to the Community Atmosphere Biosphere Land Exchange model (CABLE) applied along the Northern Australian Tropical Transect, featuring gradients in rainfall and fire disturbance. The model is able to simultaneously reproduce observation-based estimates of key functional and structural variables along the transect, namely gross primary production, tree foliage projective cover, basal area, and maximum tree height. Prospects for the use of POP to address current vegetation dynamic deficiencies in earth system modeling are discussed.

Haverd, Vanessa; Smith, Benjamin; Cook, Garry D.; Briggs, Peter R.; Nieradzik, Lars; Roxburgh, Stephen H.; Liedloff, Adam; Meyer, Carl P.; Canadell, Josep G.

2013-10-01

101

Remaining life management systems: from stand-alone to corporate memory systems and Internet (ALIAS system of MPA Stuttgart)  

Microsoft Academic Search

This paper describes an innovative and advanced system for remaining life assessment of industrial high-temperature components developed at MPA Stuttgart, Germany and being currently introduced into the power plants in Germany and several other countries. The system is a corporate memory system, essentially meaning that all the information\\/knowledge of a corporation (company, institute, etc.) should be maximally exploited in future

A. Jovanovic

1999-01-01

102

Estimation of the potential array output charge in the performance analysis of stand-alone photovoltaic systems without MPPT (Case study: Mediterranean climate)  

SciTech Connect

The potential array output energy, E{sub P}, stated by the Joint Research Centre (JRC) in their European Guidelines for the Assessment of Photovoltaic Plants and the IEC Standard 61724 does not estimate properly the potential array output of stand-alone photovoltaic (SAPV) systems without maximum power point tracker (MPPT) as it is the case for SAPV systems with MPPT and grid connected systems. In this way, the main purpose of this paper is to validate an expression that compromises simplicity and accuracy when estimating the potential array output of SAPV systems without MPPT. This issue can be of high interest to photovoltaic (PV) practitioners and experts as it can improve the analysis performance of this type of systems, helping to discriminate better the different losses in this kind of systems. Furthermore, a study of the array potential estimation through different expressions will be developed in order to evaluate which matches better the array potential output in SAPV system without MPPT. Although the analysis will be focused especially in Mediterranean climates, it will be derived some general conclusions that can be considered in other climates. (author)

Munoz, F.J.; Echbarthi, I.; Nofuentes, G.; Fuentes, M.; Aguilera, J. [Grupo IDEA, Departamento de Ingenieria Electronica y Automatica, Universidad de Jaen, Campus las Lagunillas, 23071 - Jaen (Spain)

2009-11-15

103

An evaluation of the accuracy and precision of a stand-alone submersible continuous ruminal pH measurement system.  

PubMed

The objectives of this study were 1) to develop and evaluate the accuracy and precision of a new stand-alone submersible continuous ruminal pH measurement system called the Lethbridge Research Centre ruminal pH measurement system (LRCpH; Experiment 1); 2) to establish the accuracy and precision of a well-documented, previously used continuous indwelling ruminal pH system (CIpH) to ensure that the new system (LRCpH) was as accurate and precise as the previous system (CIpH; Experiment 2); and 3) to determine the required frequency for pH electrode standardization by comparing baseline millivolt readings of pH electrodes in pH buffers 4 and 7 after 0, 24, 48, and 72 h of ruminal incubation (Experiment 3). In Experiment 1, 6 pregnant Holstein heifers, 3 lactating, primiparous Holstein cows, and 2 Black Angus heifers were used. All experimental animals were fitted with permanent ruminal cannulas. In Experiment 2, the 3 cannulated, lactating, primiparous Holstein cows were used. In both experiments, ruminal pH was determined continuously using indwelling pH electrodes. Subsequently, mean pH values were then compared with ruminal pH values obtained using spot samples of ruminal fluid (MANpH) obtained at the same time. A correlation coefficient accounting for repeated measures was calculated and results were used to calculate the concordance correlation to examine the relationships between the LRCpH-derived values and MANpH, and the CIpH-derived values and MANpH. In Experiment 3, the 6 pregnant Holstein heifers were used along with 6 new submersible pH electrodes. In Experiments 1 and 2, the comparison of the LRCpH output (1- and 5-min averages) to MANpH had higher correlation coefficients after accounting for repeated measures (0.98 and 0.97 for 1- and 5-min averages, respectively) and concordance correlation coefficients (0.96 and 0.97 for 1- and 5-min averages, respectively) than the comparison of CIpH to MANpH (0.88 and 0.87, correlation coefficient and concordance correlation coefficient, respectively). The concordance correlation analysis indicated that the ruminal pH data for LRCpH (1- and 5-min averages) vs. MANpH had location shifts that were smaller than those of the CIpH vs. MANpH. However, the scale shift was similar between the LRCpH and the CIpH. The plotted data from both systems closely resembled the line y = x, indicating that both systems were accurate and precise. In Experiment 3, changes in baseline millivolt readings for pH readings after 24, 48, or 72 h of ruminal incubation were not significantly different than zero, indicating that daily standardization of new electrodes was not essential. Results from this study indicate that the LRCpH system can accurately and precisely measure ruminal pH; thus, it provides increased opportunity for researchers to measure ruminal pH and the occurrence of ruminal acidosis in unrestrained cattle. PMID:16702280

Penner, G B; Beauchemin, K A; Mutsvangwa, T

2006-06-01

104

Fuzzy logic based DC bus voltage control of a stand alone photovoltaic\\/fuel cell\\/supercapacitor power plant  

Microsoft Academic Search

A renewable energy hybrid power plant, fed by photovoltaic (PV) and fuel cell (FC) sources with a supercapacitor (SC) storage device and suitable for distributed generation applications, is proposed herein. The PV is used as the primary source; the FC acts as a backup and a long-term storage system, feeding only the insufficiency power (steady-state) from the PV; and the

P. Thounthong; S. Sikkabut; A. Luksanasakul; P. Koseeyaporn; P. Sethakul; S. Pierfederici; B. Davat

2012-01-01

105

Three-Phase Two-Leg Inverter for Stand-Alone and Grid-Connected Renewable Energy Systems  

Microsoft Academic Search

The single-phase and three-phase renewable power generation system for distributed power applications are presented in the paper. The adopted system is consisted of a DC\\/DC converter with maximum power tracking, a full-bridge converter for isolation and DC voltage regulation and a voltage source inverter for AC power generation. The DC\\/DC converter is used to draw the maximum power from the

Bor-Ren Lin; Jyun-Ji Chen

2006-01-01

106

Evaluation of stand-alone inverters for remote applications  

NASA Astrophysics Data System (ADS)

A stand-alone or autonomous system that supplies ac electric power to loads in remote applications is a mini-utility. It requires all the basic elements of a large system. These basic elements are an energy source, a storage medium, and a power conditioner (inverter) with built-in or external control and distribution capabilities. The source for an autonomous system will probably be one of the renewable sources of energy such as wind or photovoltaics. The electrical storage will be a battery bank. The inverter, with the variable energy source and the energy storage sized for the autonomy of the system, must be capable of converting the energy and supplying controlled ac power to the loads on demand and in a safe, efficient, reliable, and compatible manner. This paper describes the evaluation of several small (typically 1-kW) stand-alone power conditioners. The purpose of these evaluations was to determine the dc input and ac output characteristics of the power conditioners, the control algorithms, and the compatibility and interactions of the power conditioners with the complex loads most likely to be used with the stand-alone or autonomous systems.

Bower, W.

107

Why icons cannot stand alone  

Microsoft Academic Search

What is the point of this paper? That an icon is like a logogram, the type of object that was created at the start of the development of writing; therefore, when first seen, an icon cannot be expected to stand alone, without descriptive, supporting material supplied as written text.

Katherine Haramundanis

1996-01-01

108

Stand-alone operation of cross-flow water turbines  

Microsoft Academic Search

A study of the stand-alone mode of operation for cross-flow-water-turbine-based generation systems is presented in this paper. This system is considered to feed a mainly resistive load via a power electronics interface which allows the use of advanced integrated controls. It should guarantee the imposed voltage parameters in the absence of energy storage elements. Experimental tests have been performed in

M. Andreica; S. Bacha; D. Roye; I. Munteanu; A. I. Bratcu; J. Guiraud

2009-01-01

109

A novel stand-alone PV generation system based on variable step size INC MPPT and SVPWM control  

Microsoft Academic Search

The power available at the output of photovoltaic (PV) cells keeps changing with solar irradiation and ambient temperature because PV cells exhibit a nonlinear current-voltage characteristic. So its maximum power point of photovoltaic cells varies with solar irradiation and ambient temperature. Maximum power point tracking (MPPT) techniques are used in PV systems to make full utilization of PV array output

Jiyong Li; Honghua Wang

2009-01-01

110

Operational optimization of a stand-alone hybrid renewable energy generation system based on an improved genetic algorithm  

Microsoft Academic Search

In a hybrid renewable energy power generation system, optimization and control is a challenging task because the behaviors of the system are becoming unpredictable and more complex. After the system is built, optimization and control of its operation is important for utilizing the renewable energy efficiently and economically. In the paper, an improved genetic algorithm is developed for achieving the

J. Zeng; M. Li; J. F. Liu; J. Wu; H. W. Ngan

2010-01-01

111

Praxiserprobung einer windkraftgetriebenen Dampfverdichtungsanlage zur Meerwasserentsalzung im vollautomatischen Inselbetrieb. Phase 4. Schlussbericht. (Field test of a wind-powered vapour compression plant for sea-water desalination in stand-alone operation. Final report).  

National Technical Information Service (NTIS)

On the North Sea island of Borkum, SEP's sea-water desalination plant based on mechanical vapor compression has been operated at a Stall-controlled wind power station. The aspired dynamic stand-alone operation was realized by a completely new control devi...

R. Coutelle P. Gaiser D. Kowalczyk

1992-01-01

112

The Compact Disk-Circulation System Interface at the Tacoma Public Library: Beyond Stand-Alone CD-ROM.  

ERIC Educational Resources Information Center

Describes the development of a CD-ROM public access catalog (CD-PAC)-circulation system interface at the Tacoma (Washington) Public Library. Cost considerations, advantages and disadvantages, access time, and currency of the CD-PAC are discussed. Sidebars cover CD-ROM and the library market, future technologies, and comparisons of prices for…

Hegarty, Kevin

1988-01-01

113

A stand-alone tree demography and landscape structure module for Earth system models: integration with global forest data  

NASA Astrophysics Data System (ADS)

Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESM). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first generation Dynamic Vegetation Models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second generation DVMs, that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to a range of forest types around the globe, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 yr. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents a preferable alternative to large-area parameterisations of woody biomass turnover, typically used in current ESMs.

Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

2014-02-01

114

Creating a stand-alone fundraising foundation.  

PubMed

When considering a stand-alone fundraising foundation, healthcare organizations should: Review the costs and benefits of starting a separate stand-alone foundation. Perform a competitive analysis to see which hospitals use them. Work with a team of legal, development, and investment advisory experts who can help map out a plan. Review governance requirements. Develop an investment policy statement. PMID:23088062

Dillingham, Walter J; Weiss, Leigh H; Lawson, John M

2012-10-01

115

DOE and AID stand-alone photovoltaic activities  

NASA Technical Reports Server (NTRS)

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system activities sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, PV-powered medical refrigerators in six countries, PV system microprocessor control development activities and PV-hybrid system assessments. The AID project includes a large village system in Tunisia, a water pumping/grain grinding project in Upper Volta, five medical clinics in four countries, PV-powered remote earth station application. These PV activities and summarizes significant findings to data are reviewed.

Bifano, W. J.; Ratajczak, A. F.

1983-01-01

116

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  

ERIC Educational Resources Information Center

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…

Bandyopadhyay, Pamela

2010-01-01

117

Stand-alone irrigation pumping with wind energy  

SciTech Connect

Windpower is one of the oldest forms of energy used for pumping water. Several thousand windmills are still used today to provide water for livestock and domestic needs. Because of the large water volume needed for irrigation, irrigators have selected natural gas, electricity, or diesel fuel as power sources for their irrigation pump. Wind turbines have been successfully used to generate electricity to supplement electrical requirements of irrigation systems; however, not all irrigation pumps have electricity readily available. Because of the need for an independent, high-volume pumping system powered by the wind, the USDA-ARS, Bushland, TX and the Alternative Energy Institute, Canyon, TX have designed and constructed a stand-alone wind-powered pumping system. The initial effort was an in-depth study of all types of pumps in order to locate a pump which could deliver a steady 15-to-20 l/s flow rate while the input power varied in rpm and torque. A progressive-cavity pump was selected as being best for use in moderate and deep well applications where the total head was more than 15 m. A 10-cm progressive-cavity pump was purchased and installed on a 4-kW vertical-axis wind turbine with a mechanical linkage between the wind turbine and pump. Performance data indicated that flow was 10 l/s, and head 12 m at a windspeed of 16 m/s. When the windspeed dropped to 9 m/s, the pumping load caused the wind turbine to stall. Because of the highly variable power output of the wind turbine, no presently-manufactured pump is satisfactory for stand-alone irrigation pumping.

Clark, R.N.

1982-12-01

118

A novel stand-alone dual stator-winding induction generator with static excitation regulation  

Microsoft Academic Search

On the basis of the new idea of electric power integration, a novel stand-alone dual stator-winding induction generator (DWIG) system is built. In this generator, there are two sets of windings to be embedded in the stator slots. One, referred to as the 12-phase power winding, supplies power to the dc load via a 12-phase bridge rectifier, and the other,

Dong Wang; Weiming Ma; Fei Xiao; Botao Zhang; Dezhi Liu; An Hu

2005-01-01

119

Small Wind Turbine with Battery Storage Stand-Alone Experiment.  

National Technical Information Service (NTIS)

An experiment to evaluate battery storage with a stand-alone wind generator system is being pursued jointly by Sandia National Laboratories (SNL) and the Rocky Flats Small (<100 kW) Wind Systems Test Facility (Rockwell International). The goal of the expe...

P. C. Butler J. M. Freese D. W. Miller G. D. Price J. N. Carlson

1983-01-01

120

Stand-alone microprobe at Livermore  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories/California have jointly constructed a new stand-alone microprobe facility. Although the facility was built to develop a method to rapidly locate and determine elemental concentrations of micron scale particulates on various media using PIXE, the facility has found numerous applications in biology and materials science. The facility is located at LLNL and uses a General Ionex Corporation Model 358 duoplasmatron negative ion source, a National Electrostatics Corporation 5SDH-2 tandem accelerator, and an Oxford triplet lens. Features of the system include complete computer control of the beam transport using LabVIEWTM for Macintosh, computer controlled beam collimating and divergence limiting slits, automated sample positioning to micron resolution, and video optics for beam positioning and sample observation. Data collection is accomplished with the simultaneous use of as many as four EG&G Ortec IGLET-XTM X-Ray detectors, digital amplifiers made by X-Ray Instruments and Associates (XIA), and LabVIEWTM for Macintosh acquisition software.

Antolak, A J; Bench, G S; Brown, T A; Frantz, B R; Grant, P G; Morse, D H; Roberts, M L

1998-10-02

121

The stand-alone microprobe at Livermore  

NASA Astrophysics Data System (ADS)

Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories/California have jointly constructed a new stand-alone microprobe facility. Although the facility was built to develop a method to rapidly locate and determine elemental concentrations of micron scale particulates on various media using PIXE, the facility has found numerous applications in biology and materials science. The facility is located at LLNL and uses a General Ionex Corporation Model 358 duoplasmatron negative ion source, a National Electrostatics Corporation 5SDH-2 tandem accelerator, and an Oxford triplet lens. Features of the system include complete computer control of the beam transport using LabVIEW™ for Macintosh, computer controlled beam collimating and divergence limiting slits, automated sample positioning to micron resolution, and video optics for beam positioning and sample observation. Data collection is accomplished with the simultaneous use of as many as four EG&G Ortec IGLET-X™ X-Ray detectors, digital amplifiers made by X-Ray Instruments and Associates (XIA), and LabVIEW™ for Macintosh acquisition software.

Roberts, M. L.; Grant, P. G.; Bench, G. S.; Brown, T. A.; Frantz, B. R.; Morse, D. H.; Antolak, A. J.

1999-10-01

122

Renewable hybrid stand-alone telecom power system modeling and analysis  

Microsoft Academic Search

At the telecom service providers' installations, the problem of poor grid electricity supply is tackled by using diesel generators. These generators, however, entail a major problem in transportation and storage of diesel with noise pollution. Decentralized distributed generation technologies based on renewable energy resources such as solar photo voltaic (SPV) or\\/and wind turbine generators (WTG) address the above barriers to

Prabodh Bajpai; N. P. Prakshan; N. K. Kishore

2009-01-01

123

Assessment of a stand-alone gradual capacity reverse osmosis desalination plant to adapt to wind power availability: A case study  

Microsoft Academic Search

Desalination driven by renewable energies is an interesting technology in isolated coastal areas. Its feasibility and reliability are guaranteed by innumerable designs implemented and experiences carried out, mainly focused on small capacity systems. However, only mature and efficient technologies are suitable for medium or large scale desalination. In the case of seawater desalination, wind-powered reverse osmosis is the most efficient,

Baltasar Peñate; Fernando Castellano; Alejandro Bello; Lourdes García-Rodríguez

2011-01-01

124

Recharging of batteries\\/supercapacitors hybrid source for electric vehicles application using photovoltaic energy in a stand-alone point  

Microsoft Academic Search

The production of electrical energy by photovoltaic systems is highly dependent on weather conditions. Therefore, this energy should be stored during the day and restored during the night. This paper deals with the storage and generation systems using renewable energy sources. A stand-alone combined system with electrochemical batteries and supercapacitors is considered. The power flow among the different storage devices

M. Benaouadj; A. Aboubou; M. Becherif; M. Y. Ayad; M. Bahri

2012-01-01

125

Application of valve-regulated lead-acid batteries for storage of solar electricity in stand-alone photovoltaic systems in the northwest areas of China  

Microsoft Academic Search

Photovoltaic (PV) installations for solar electric power generation are being established rapidly in the northwest areas of China, and it is increasingly important for these power systems to have reliable and cost effective energy storage. The lead-acid battery is the more commonly used storage technology for PV systems due to its low cost and its wide availability. However, analysis shows

Shounan Hua; Qingshen Zhou; Delong Kong; Jianping Ma

2006-01-01

126

Analysis of stand-alone GPS for relative location discovery in wireless sensor networks  

Microsoft Academic Search

In this paper, we use experiments to examine the accuracy of standalone Global positioning System (GPS) for relative location discovery in wireless sensor networks. The relative locations are obtained by comparison of stand-alone global GPS position fixes. We seek to find out if stand-alone GPS measurements from inexpensive GPS receivers can result in the relative positioning accuracies desired. Various sensor

Yifeng Zhou; Jeremy Schembri; Louise Lamont; Jeff Bird

2009-01-01

127

Hybrid energy storage systems for stand-alone electric power systems: optimization of system performance and cost through control strategies 1 1 This manuscript has been authored by a contractor of the United States Government under contract. Accordingly the United States Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for United States Government purposes  

Microsoft Academic Search

The development of remote, renewable-based energy is hindered in part by the lack of affordable energy storage. Requiring power-on-demand from an energy system powered by intermittent or seasonal sources may necessitate one-month’s energy storage—an expensive proposition using conventional storage technologies. If multiple energy storage devices with complementary performance characteristics are used together, the resulting ‘hybrid energy-storage system’ can dramatically reduce

S. R. Vosen; J. O. Keller

1999-01-01

128

A stand-alone peristaltic micropump based on piezoelectric actuation.  

PubMed

Despite significant efforts to develop micropumps, cumbersome driving equipment means that the design of portable micropumps remains a challenge. This study presents a stand-alone micropump system, which includes a peristaltic micropump based on piezoelectric actuation and a driving circuit. This battery-based driving circuit comprises a 12 V battery, an ATmega 8535 microprocessor, a 12 V-to-180 V DC to DC converter using transformerless technology, three differential amplifiers, an IC 7805, a phase controller, an A/D converter, a keyboard and an LCD module. The system can produce step-function signals with voltages of up to 228 V(pp) and frequencies ranging from 10 Hz to 100 kHz, as the inputs for the pump. It is portable and programmable with the package size of 22 x 12.8 x 9 cm. Additionally, this proposed system is used to design the driving signals of the pump which are 3-, 4, and 6-phase actuation sequences. This work performs the circuit testing and fluid pumping, and demonstrates the effects of actuation sequences on pump performance in terms of the dynamic behavior of the diaphragm, flow rates, back pressure and power consumption of the system. The experimental results show that the pump excited by the 6-phase sequence results in better performance compared with the 3- and 4-phase sequences, and produces a maximum flow rate of 36.8 microl/min and a maximum back pressure of 520 Pa with deionized water at 100 V (pp) and 700 Hz. PMID:17160705

Jang, Ling-Sheng; Li, Yuan-Jie; Lin, Sung-Ju; Hsu, Yi-Chu; Yao, Wu-Sung; Tsai, Mi-Ching; Hou, Ching-Cheng

2007-04-01

129

Experimental investigation and modelling of the interaction between an AVR and ballast load frequency controller in a stand-alone micro-hydroelectric system  

Microsoft Academic Search

Extensive field experience in micro-hydroelectric systems in remote rural communities demonstrates that the use of a typical automatic voltage regulator (AVR), as supplied with a brushless self-exciting synchronous alternator, can be the cause of unsatisfactory system performance. This paper presents results from experiments undertaken on a full-scale micro-hydroelectric test rig as well as system modelling with PSCAD. The source of

R. Jarman; P. Bryce

2007-01-01

130

Sizing a hybrid wind-diesel stand-alone system on the basis of minimum long-term electricity production cost  

Microsoft Academic Search

Hybrid wind-diesel systems are an interesting solution for the electrification of isolated consumers. The proposed system, including a properly sized battery, leads to a significant reduction of the fuel consumption, in comparison with a diesel-only installation, also protecting the diesel generator from excessive wear. On the other hand, a properly designed wind-diesel installation remarkably reduces the required battery capacity, in

J. K. Kaldellis; E. Kondili; A. Filios

2006-01-01

131

CAD-based stand-alone spacecraft radiation exposure analysis system: An application of the early man-tended Space Station  

NASA Technical Reports Server (NTRS)

Major improvements have been completed in the approach to analyses and simulation of spacecraft radiation shielding and exposure. A computer-aided design (CAD)-based system has been developed for determining the amount of shielding provided by a spacecraft and simulating transmission of an incident radiation environment to any point within or external to the vehicle. Shielding analysis is performed using a customized ray-tracing subroutine contained within a standard engineering modeling software package. This improved shielding analysis technique has been used in several vehicle design programs such as a Mars transfer habitat, pressurized lunar rover, and the redesigned international Space Station. Results of analysis performed for the Space Station astronaut exposure assessment are provided to demonastrate the applicability and versatility of the system.

Appleby, M. H.; Golightly, M. J.; Hardy, A. C.

1993-01-01

132

CAD-based stand-alone spacecraft radiation exposure analysis system: An application of the early man-tended Space Station  

NASA Astrophysics Data System (ADS)

Major improvements have been completed in the approach to analyses and simulation of spacecraft radiation shielding and exposure. A computer-aided design (CAD)-based system has been developed for determining the amount of shielding provided by a spacecraft and simulating transmission of an incident radiation environment to any point within or external to the vehicle. Shielding analysis is performed using a customized ray-tracing subroutine contained within a standard engineering modeling software package. This improved shielding analysis technique has been used in several vehicle design programs such as a Mars transfer habitat, pressurized lunar rover, and the redesigned international Space Station. Results of analysis performed for the Space Station astronaut exposure assessment are provided to demonastrate the applicability and versatility of the system.

Appleby, M. H.; Golightly, M. J.; Hardy, A. C.

133

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  

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

134

Executive Summary of The Use of Educational Software in Adult Literacy Programs: A Comparison of Integrated Learning Systems and Stand-Alone Software=Resume du Rapport Intitule: L'Utilisation de Didacticiels dans les Programmes d'Alphabetisation des Adultes: Une Comparaison Entre les Systemes Integres d'Apprentissage et les Logiciels Autonomes.  

ERIC Educational Resources Information Center

The pros and cons of integrated learning systems (ILS) and stand-alone software for adult literacy instruction were examined in a comparative analysis that focused on their use in adult literacy programs in Canada. The comparison focused on the following variables: achievement gains in reading; changes in students' attitudes toward computers;…

Millar, Diane

135

Battery charger with MPPT function for stand-alone wind turbines  

Microsoft Academic Search

In this paper, a buck-type power converter as the battery charger for the stand-alone wind turbine is proposed. The proposed power converter can harvest the maximum power from the wind turbine while generating pulsating current for the battery bank to improve the charging efficiency. The maximum power point tracking (MPPT) function is realized by the circuit parameter design of the

Kuo-Yuan Lo; Yung-Ruei Chang; Yaw-Ming Chen

2010-01-01

136

Decentralized\\/stand-alone hybrid Wind–Diesel power systems to meet residential loads of hot coastal regions  

Microsoft Academic Search

In view of rising costs, pollution and fears of exhaustion of oil and coal, governments around the world are encouraging to seek energy from renewable\\/sustainable energy sources such as wind. The utilization of energy from wind (since the oil embargo of the 1970s) is being widely disseminated for displacement of fossil fuel produced energy and to reduce atmospheric degradation. A

M. A. Elhadidy; S. M. Shaahid

2005-01-01

137

Artificial neural network model for prediction solar radiation data: application for sizing stand-alone photovoltaic power system  

Microsoft Academic Search

The prediction of daily global solar radiation data is very important for many solar applications, possible application can be found in meteorology, renewable energy and solar conversion energy. In this paper, we investigate using radial basis function (RBF) networks in order to find a model for daily global solar radiation data from sunshine duration and air temperature. This methodology is

A. Mellit; M. Menghanem; M. Bendekhis

2005-01-01

138

Feasibility analysis of stand-alone renewable energy supply options for a large hotel  

Microsoft Academic Search

This paper provides a feasibility analysis of renewable energy supply (RES) for a stand-alone supply large-scale tourist operation (with over 100 beds). The analysis utilises the power load data from a hotel located in a subtropical coastal area of Queensland, Australia. The assessment criteria of the analysis are net present cost, renewable factor and payback time. Due to the limited

G. J. Dalton; D. A. Lockington; T. E. Baldock

2008-01-01

139

Flexible control of small wind turbines with grid failure detection operating in stand-alone and grid-connected mode  

Microsoft Academic Search

This paper presents the development and test of a flexible control strategy for an 11-kW wind turbine with a back-to-back power converter capable of working in both stand-alone and grid-connection mode. The stand-alone control is featured with a complex output voltage controller capable of handling nonlinear load and excess or deficit of generated power. Grid-connection mode with current control is

Remus Teodorescu; Frede Blaabjerg

2004-01-01

140

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

Microsoft Academic Search

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

R. Posadillo; R. López Luque

2008-01-01

141

PWM-VSI inverter-assisted stand-alone dual stator winding induction generator  

Microsoft Academic Search

This paper presents a novel usage of a dual stator winding three-phase induction machine as a stand-alone generator with both controlled output load voltage magnitude and frequency. This generator, with both three-phase power and control windings housed in the stator structure, has the load connected to the power winding and a three-phase pulsewidth modulation (PWM) voltage-source inverter sourcing the control

Olorunfemi Ojo; I. E. Davidson

2000-01-01

142

PWM-VSI inverter assisted stand-alone dual stator winding induction generator  

Microsoft Academic Search

This paper presents a novel usage of a dual stator winding, three-phase induction machine as a stand-alone generator with both controlled output load voltage magnitude and frequency. This generator, with both three-phase power and control windings housed in the stator structure, has the load connected to the power winding and a three-phase PWM voltage source inverter sourcing the control winding.

Olorunfemi Ojo; Innocent E. Davidson

1999-01-01

143

Hanford tank initiative cone penetrometer stand alone grouting module  

SciTech Connect

The HTI subsurface characterization task will use the Hanford Cone Penetrometer platform (CPP) to deploy contaminant sensor and soil sampling probes into the vadose zone surrounding SST 241-AX-104. Closure of the resulting penetration holes may be stipulated by WAC requirements. A stand alone grouting capability deployable by the CPP has been developed. This qualification test plan defines testing of this capability to be performed at the Immobilized Low Activity Waste Disposal Complex.

CALLAWAY, W.S.

1998-10-15

144

Reliability evaluation of stand-alone hybrid microgrid using Sequential Monte Carlo Simulation  

Microsoft Academic Search

Adequacy assessment of a stand-alone microgrid including diesel generator (DG), Micro Gas Turbine(MGT), Wind Turbine Generator(WTG), and Photovoltaic(PV) with different configurations is carried out using Sequential Monte Carlo Simulation(SMCS) method. To obtain the output power of WTG and PV, some atmospheric data such as wind speed, solar irradiation, and ambient temperature data are needed. Weibull distribution is used to obtain

Mohammad Moradi Ghahderijani; S. Masoud Barakati; Saeed Tavakoli

2012-01-01

145

Performance Prediction of a Stand-Alone Permanent-Magnet Induction Generator  

NASA Astrophysics Data System (ADS)

A permanent-magnet induction generator (PMIG) is a special induction machine self-excited from the inside of the squirrel-cage rotor by a permanent-magnet (PM) rotor. The PMIG can be made to operate as a stand-alone generator when the squirrel-cage rotor is driven by an external prime mover. Moreover, if the capacitors are connected across the stator terminals, adjusting their values can control the output voltage. This paper presents a method for predicting the steady-state performance of such a stand-alone PMIG theoretically. By introducing the per-unit system, a nonlinear equivalent circuit, which can include the variation of the circuit parameters, is derived. Based on this equivalent circuit, the steady-state performance is theoretically calculated, and its validity is confirmed through experiments.

Fukami, Tadashi; Shimizu, Bungo; Hanaoka, Ryoichi; Takata, Shinzo; Miyamoto, Toshio

146

Magnetic field measurements near stand-alone transformer stations.  

PubMed

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. PMID:23836796

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

2013-12-01

147

Modeling and simulation of a stand-alone photovoltaic plant with MPPT feature and dedicated battery storage  

Microsoft Academic Search

This paper reports on the modeling and simulation of a stand-alone photovoltaic (PV) plant with maximum power point tracking (MPPT) feature and dedicated battery storage. The overall plant comprises the PV module, battery bank, MPPT module, controller, inverter and a resistive load. The load is supplied by both the PV and the battery bank. The fluctuations in the output of

N. W. Vanden Eynde; S. P. Chowdhury

2010-01-01

148

Composite Loads in Stand-Alone Inverter-Based Microgrids—Modeling Procedure and Effects on Load Margin  

Microsoft Academic Search

This paper details a modeling procedure that incorporates composite loads in stand-alone microgrids in which, because of the low system inertia provided by inverter-interfaced generation units, the grid dynamics is not neglected. The paper introduces a methodology based on 1) separately treating the plants (RL grid elements) from reference frames and control systems; and 2) establishing a vector valued function

Guzmán Diaz; Cristina Gonzalez-Moran; Javier Gomez-Aleixandre; Alberto Diez

2010-01-01

149

Stand alone induction generator with terminal impedance controller and no turbine controls  

Microsoft Academic Search

Induction generators with hydraulic turbines are often used for cogeneration. The same turbine generator configuration can be used for stand-alone generation if an impedance controller is connected to the generator terminals; this configuration requires no hydraulic controls on the turbine. The authors propose an electronic impedance controller to control the voltage and the frequency of a stand-alone induction generator. The

R. Bonert; G. Hoops

1990-01-01

150

Stand-Alone Hardware-Based Learning System  

NASA Astrophysics Data System (ADS)

The probabilistic Random Access Memory (pRAM) is a biologically-inspired model of a neuron. The pRAM behaviour is described in this paper in relation to binary and real-valued input vectors. The pRAM is hardware-realisable, as is its reinforcement training algorithm. The pRAM model may be applied to a wide range of artificial neural network applications, many of which are classification tasks. The application presented here is a control problem where an inverted pendulum, mounted on a cart, is to be balanced. The solution to this problem using the pRAM-256, a VLSI pRAM controller, is shown.

Clarkson, Trevor; Ng, Chi

1995-02-01

151

Voltage controlled stand-alone microhydro induction generator system  

Microsoft Academic Search

The paper discusses simulated control cases of the wound rotor self-excited induction generator WRSEIG. The generator external controller is designed to regulate the output voltage and frequency for constant or variable speed operation of the prime mover and has the inherent capability of protecting the load from short circuit, which permits voltage collapse under heavy loads. WRSEIG is self-excited using

K. A. Nigim

2005-01-01

152

A rule-based fuzzy logic controller for a PWM inverter in a stand alone wind energy conversion scheme  

Microsoft Academic Search

The paper presents a rule-based fuzzy logic controller to control the output power of a pulse width modulated (PWM) inverter used in a stand-alone wind energy conversion scheme (SAWECS). The self-excited induction generator used in SAWECS has the inherent problem of fluctuations in the magnitude and frequency of its terminal voltage with changes in wind velocity and load. To overcome

Rohin M. Hilloowala; Adel M. Sharaf

1996-01-01

153

Probabilistic modeling of solar power systems  

Microsoft Academic Search

The author presents a probabilistic approach based on Markov chain theory to model stand-alone photovoltaic power systems and predict their long-term service performance. The major advantage of this approach is that it allows designers and developers of these systems to analyze the system performance as well as the battery subsystem performance in the long run and determine the system design

Fayssal M. Safie

1989-01-01

154

Market assessment of photovoltaic power systems for agricultural applications in Nigeria  

NASA Technical Reports Server (NTRS)

The market potential for stand-alone photovoltaic systems in agriculture was studied. Information is presented on technical and economically feasible applications, and assessments of the business, government and financial climate for photovoltaic sales. It is concluded that the market for stand-alone systems will be large because of the availability of captial and the high premium placed on high reliability, low maintenance power systems. Various specific applications are described, mostly related to agriculture.

Staples, D.; Steingass, H.; Nolfi, J.

1981-01-01

155

Stand-alone response regulators controlling global virulence networks in streptococcus pyogenes.  

PubMed

Global regulation of virulence gene expression via transcriptional regulators plays a central role in the ability of the bacterial pathogen Streptococcus pyogenes (the group A Streptococcus, GAS) to rapidly adapt during infection. The 'stand-alone' regulators Mga, RofA-like proteins (RALPs), and RopB/Rgg control important and diverse virulence regulons in response to growth-related signals and other environmental conditions in GAS. Stand-alone regulated genes encode factors important for colonization of tissues, immune evasion, persistence, dissemination, metabolism, and the response to stressors. Although conserved 'core' regulons have been established for each, recent studies have revealed significant inter-serotype and even intra-serotype variation in the regulatory patterns presented by the stand-alone regulators. This chapter will look at each stand-alone regulatory pathway in depth and discuss how these important global networks influence virulence as well as interact with each other to produce an integrated response during GAS infection. PMID:19494581

McIver, Kevin S

2009-01-01

156

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

PubMed

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. PMID:12290699

Mustafa, A

1995-01-01

157

Array structure design handbook for stand alone photovoltaic applications  

NASA Technical Reports Server (NTRS)

This handbook will permit the user to design a low-cost structure for a variety of photovoltaic system applications under 10 kW. Any presently commercially available photovoltaic modules may be used. Design alternatives are provided for different generic structure types, structural materials, and electric interfaces. The use of a hand-held calculator is sufficient to perform the necessary calculations for the array designs.

Didelot, R. C.

1980-01-01

158

Performance Analysis of a Stand-Alone Permanent-Magnet Induction Generator with Single-Phase Output  

NASA Astrophysics Data System (ADS)

The performance of a stand-alone permanent-magnet induction generator (PMIG) with single-phase output is analyzed using the method of symmetrical components and is compared to that of the same-sized conventional induction generator (IG). Experimental results conducted on a 2.2-kW testing machine are also provided to justify the theoretical analysis. Calculation and experimental results show that containing a permanent-magnet (PM) rotor generates electric power without fail and contributes to the improvement of efficiency and frequency variation.

Tsuda, Toshihiro; Fukami, Tadashi; Kanamaru, Yasunori; Miyamoto, Toshio

159

NOY: a neutrino observatory network project based on stand alone air shower detector arrays  

NASA Astrophysics Data System (ADS)

We have developed a self powered stand alone particle detector array dedicated to the observation of horizontal tau air showers induced by high energy neutrinos interacting in mountain rock. Air shower particle detection reaches a 100% duty cycle and is practically free of background when compared to Cherenkov light or radio techniques. It is thus better suited for rare neutrino event search. An appropriate mountain to valley topological configuration has been identified and the first array will be deployed on an inclined slope at an elevation of 1500 m facing Southern Alps near the city of Grenoble (France). A full simulation has been performed. A neutrino energy dependent mountain tomography chart is obtained using a neutrino and tau propagation code together with a detailed cartography and elevation map of the region. The array acceptance is then evaluated between 1 PeV and 100 EeV by simulating decaying tau air showers across the valley. The effective detection surface is determined by the shower lateral extension at array location and is hence much larger than the array geometrical area. The array exposure will be 1014 cm2 sr s at 100 PeV. Several independent arrays can be deployed with the aim of constituting a large distributed observatory. Some other sites are already under study. At last, special care is dedicated to the educational and outreach aspects of such a cosmic ray detector.

Montanet, F.; Lebrun, D.; Chauvin, J.; Lagorio, E.; Stassi, P.

2011-09-01

160

A fast, programmable, stand-alone pulse generator emulating spectroscopy nuclear events  

SciTech Connect

The design of a fast, programmable, stand-alone pulse generator emulating spectroscopy nuclear events is described. The generator is one unit in a system aiming to test the validity of the simulation and theoretical work relating to the shaping, acquisition, and processing of spectroscopy signals in different experimental situations arising from different technical and scientific fields. The generator output, which also includes piled-up shapes, can be used in many different ways. For example, it can be used: (1) as an input to a charge sensitive preamplifier and shaping amplifier system; (2) as an input to a module for real-time digital shaping of spectroscopy pulses; and (3) it can generate a digital sequence emulating a digitally sampled analog pulse. The signals that it can emulate include those from simple charge sensitive preamplifiers, from more refined analog shapers, and the signals generated directly from scintillation detectors. The main element of the generator is the Analog Devices 21060, a fast and flexible digital signal processor (DSP). This paper considers various generator configurations arising from the need to reach a compromise among generator speed, shape resolution, and memory requirements. It is possible to program both the emulated average counting rate and the time interval between two consecutive samples (tns) using a predetermined pulse shape. The minimum tns value is equal to 10 ns in parallel configurations.

Imperiale, C. [Pacific Western Univ., Los Angeles, CA (United States). Technological Div.] [Pacific Western Univ., Los Angeles, CA (United States). Technological Div.

1996-10-01

161

PC-PCL-based control system for the high-voltage pulsed-power operation of the Intense Diagnostic Neutral Beam (IDNB) Experiment.  

National Technical Information Service (NTIS)

A stand-alone, semiautomated control system for the high-voltage pulsed-power energy sources on the Intense Diagnostic Neutral Beam Experiment at Los Alamos National Laboratory using personal computer (PC) and programmable logic controller (PLC) technolog...

R. Gribble

1993-01-01

162

Overcoming the Challenges of Stand-Alone Multicultural Courses: The Possibilities of Technology Integration  

ERIC Educational Resources Information Center

The enclosed manuscript discusses the challenges (student resistance, institutional time constraints, course isolation) of a successful conventional stand-alone multicultural course and describes how these challenges were overcome with the incorporation of technology into the instruction and assessment process. The article describes how…

Brown, Elinor L.

2004-01-01

163

EVALUATION AND USE OF STAND-ALONE COMMERCIAL PHOTOLYTIC CONVERTERS FOR NO2 TO NO CONVERSION  

EPA Science Inventory

Two types of stand-alone commercial photolytic converters of NO2 to NO are now available for use with NO, O3 chemiluminescence monitors for the measurement of NO2. Both units have been tested for interferences resulting from photolysis of HONO or from decomposition of PAN. On...

164

Stand-Alone Vision Sensor Design Based on Fuzzy Associative Database  

Microsoft Academic Search

In this paper a comprehensive design methodology for stand-alone vision sensor with application in manufacturing production lines is presented. The sensor can be employed as a substitute for traditional sensors, such as photoelectric and proximity sensors. The advantage of the vision sensor over traditional manufacturing sensors is distinguishing the incoming product prior to determination of the product position. The sensor

Shahed Shahir

2004-01-01

165

Synchronization and Mains Outage Detection for Controlled Grid Connection of the Wind Driven Variable Speed Power Generation System  

Microsoft Academic Search

Power electronics devices used in power generation systems with electrical machines allow variable speed operation. A high quality output power is delivered to the transmission network. Moreover the power electronics allow stand alone operation in an island power systems, as well as in grid connected systems during the mains outage. This way the variable speed power generation systems are useful

G. Iwanski; W. Koczara

2007-01-01

166

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

PubMed Central

Summary: 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. Contact: alberto@cs.rhul.ac.uk Availability: 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.

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

2014-01-01

167

[Revision strategies for ventral implant failure in the lumbar spine exemplified by stand-alone cages].  

PubMed

This article gives a review of the possible revision strategies after repeated operative treatment of degenerative spinal diseases using stand-alone cages. Own clinical experiences and reports from the literature were taken into consideration. Dorsal stabilization is the main consideration for all access routes even if it can be discussed, albeit controversially, whether ventral removal of an installed cage is justified, because this contains a significantly higher perioperative risk. The increased risk of neurological complications by dorsal revision and for vascular complications by ventral access, especially at the L4/5 level must be particularly considered. Clinical data and own experience have shown that in the majority of cases an additional dorsal stabilization should be favored for revision surgery. Currently large clinical studies which deal with the revision problematic of stand-alone cages with respect to the access route are still lacking. PMID:21308464

Tarhan, T; Rauschmann, M

2011-02-01

168

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

PubMed

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 keyboard 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. PMID:3387606

Tsutsumi, R; Takahashi, K; Sato, T; Komatani, A; Yamaguchi, K

1988-03-01

169

SADIST (the SAndia Data Index STructure): a stand-alone data base for computer-aided design and general use  

SciTech Connect

A file structure has been designed that fills the needs of multilevel hierarchical design of integrated circuits (ICs). Since the structure is actualized by a stand-alone FORTRAN program, it is applicable to general-purpose use in situations where the structure of the data modeled is similar to that of IC data. Though the structure itself is a FORTRAN direct-access file, its interface with user programs is a small sequential subfile accessible to FORTRAN, PASCAL, and most other languages. This ability facilitates linkup to systems already in use and requires minimal recoding. Backup, restore, and other data base recovery and integrity operations are automatic, but may be initiated by the user if desired. 3 figures.

Stauffer, J D

1980-11-01

170

Integrating a Redox Flow Battery System with a Wind-Diesel Power System  

Microsoft Academic Search

Energy storage devices are required for power quality maintenance in stand alone power systems like wind-diesel ones. A redox flow battery system has many virtues which make its integration with a wind-diesel power system attractive. This paper proposes the integration of a redox flow battery system with a typical multi-machine wind-diesel power system for simultaneous voltage and frequency regulation. The

S. A. Lone; M.-u-D. Mufti

2006-01-01

171

Fracture of the L-4 vertebral body after use of a stand-alone interbody fusion device in degenerative spondylolisthesis for anterior L3-4 fixation.  

PubMed

Many studies attest to the excellent results achieved using anterior lumbar interbody fusion (ALIF) for degenerative spondylolisthesis. The purpose of this report is to document a rare instance of L-4 vertebral body fracture following use of a stand-alone interbody fusion device for L3-4 ALIF. The patient, a 55-year-old man, had suffered intractable pain of the back, right buttock, and left leg for several weeks. Initial radiographs showed Grade I degenerative spondylolisthesis, with instability in the sagittal plane (upon 15° rotation) and stenosis of central and both lateral recesses at the L3-4 level. Anterior lumbar interbody fusion of the affected vertebrae was subsequently conducted using a stand-alone cage/plate system. Postoperatively, the severity of spondylolisthesis diminished, with resolution of symptoms. However, the patient returned 2 months later with both leg weakness and back pain. Plain radiographs and CT indicated device failure due to anterior fracture of the L-4 vertebral body, and the spondylolisthesis had recurred. At this point, bilateral facetectomies were performed, with reduction/fixation of L3-4 by pedicle screws. Again, degenerative spondylolisthesis improved postsurgically and symptoms eased, with eventual healing of the vertebral body fracture. This report documents a rare instance of L-4 vertebral body fracture following use of a stand-alone device for ALIF at L3-4, likely as a consequence of angular instability in degenerative spondylolisthesis. Under such conditions, additional pedicle screw fixation is advised. PMID:24725181

Kwon, Yoon-Kwang; Jang, Ju-Hee; Lee, Choon-Dae; Lee, Sang-Ho

2014-06-01

172

Life-cycle cost comparisons of advanced storage batteries and fuel cells for utility, stand-alone, and electric vehicle applications  

SciTech Connect

This report presents a comparison of battery and fuel cell economics for ten different technologies. To develop an equitable economic comparison, the technologies were evaluated on a life-cycle cost (LCC) basis. The LCC comparison involved normalizing source estimates to a standard set of assumptions and preparing a lifetime cost scenario for each technology, including the initial capital cost, replacement costs, operating and maintenance (O M) costs, auxiliary energy costs, costs due to system inefficiencies, the cost of energy stored, and salvage costs or credits. By considering all the costs associated with each technology over its respective lifetime, the technology that is most economical to operate over any given period of time can be determined. An analysis of this type indicates whether paying a high initial capital cost for a technology with low O M costs is more or less economical on a lifetime basis than purchasing a technology with a low initial capital cost and high O M costs. It is important to realize that while minimizing cost is important, the customer will not always purchase the least expensive technology. The customer may identify benefits associated with a more expensive option that make it the more attractive over all (e.g., reduced construction lead times, modularity, environmental benefits, spinning reserve, etc.). The LCC estimates presented in this report represent three end-use applications: utility load-leveling, stand-alone power systems, and electric vehicles.

Humphreys, K.K.; Brown, D.R.

1990-01-01

173

TS Fuzzy Maximum Power Point Tracking Control of Solar Power Generation Systems  

Microsoft Academic Search

This paper presents maximum power point tracking (MPPT) control for stand-alone solar power generation systems via the Takagi-Sugeno (T-S) fuzzy-model-based approach. In detail, we consider a dc\\/dc buck converter to regulate the output power of the photovoltaic panel array. First, the system is represented by the T-S fuzzy model. Next, in order to reduce the number of measured signals, a

Chian-Song Chiu

2010-01-01

174

Energy Balance Associated with the Use of a Maximum Power Tracer in a 100-KW-Peak Power System.  

National Technical Information Service (NTIS)

Design of a stand-alone photovoltaic (PV) system which includes batteries for energy storage requires not only sizing the array power output and battery storage capacity to meet the load, but also fixing the number of battery cells placed in series relati...

L. L. Bucciarelli B. L. Grossman E. F. Lyon N. E. Rasmussen

1980-01-01

175

Biomechanical comparison of three stand-alone lumbar cages -- a three-dimensional finite element analysis  

PubMed Central

Background For anterior lumbar interbody fusion (ALIF), stand-alone cages can be supplemented with vertebral plate, locking screws, or threaded cylinder to avoid the use of posterior fixation. Intuitively, the plate, screw, and cylinder aim to be embedded into the vertebral bodies to effectively immobilize the cage itself. The kinematic and mechanical effects of these integrated components on the lumbar construct have not been extensively studied. A nonlinearly lumbar finite-element model was developed and validated to investigate the biomechanical differences between three stand-alone (Latero, SynFix, and Stabilis) and SynCage-Open plus transpedicular fixation. All four cages were instrumented at the L3-4 level. Methods The lumbar models were subjected to the follower load along the lumbar column and the moment at the lumbar top to produce flexion (FL), extension (EX), left/right lateral bending (LLB, RLB), and left/right axial rotation (LAR, RAR). A 10 Nm moment was applied to obtain the six physiological motions in all models. The comparison indices included disc range of motion (ROM), facet contact force, and stresses of the annulus and implants. Results At the surgical level, the SynCage-open model supplemented with transpedicular fixation decreased ROM (>76%) greatly; while the SynFix model decreased ROM 56-72%, the Latero model decreased ROM 36-91%, in all motions as compared with the INT model. However, the Stabilis model decreased ROM slightly in extension (11%), lateral bending (21%), and axial rotation (34%). At the adjacent levels, there were no obvious differences in ROM and annulus stress among all instrumented models. Conclusions ALIF instrumentation with the Latero or SynFix cage provides an acceptable stability for clinical use without the requirement of additional posterior fixation. However, the Stabilis cage is not favored in extension and lateral bending because of insufficient stabilization.

2013-01-01

176

Are integrated HIV services less stigmatizing than stand-alone models of care? A comparative case study from Swaziland  

PubMed Central

Introduction Integrating HIV with primary health services has the potential to reduce HIV-related stigma through delivering care in settings disassociated with HIV. This study investigated the relationship between integrated care and felt stigma. The study design was a comparative case study of four models of HIV care in Swaziland, ranging from fully integrated to fully stand-alone HIV care. Methods An exit survey (N=602) measured differences in felt stigma across model of care; the primary outcome “perception of HIV status exposure through clinic attendance” was analyzed using multivariable logistic regression. In-depth interviews (N=22) explored whether and how measured differences in stigma experiences were related to service integration. Results There were significant differences in perceived status exposure across models of care. After adjustment for potential confounding between sites, those at a partially integrated site and a partially stand-alone site had greater odds of perceived status exposure than those at the fully stand-alone site (aOR 3.33, 95% CI 1.98–5.60; and aOR 11.84, 95% CI 6.89–20.36, respectively). There was no difference between the fully stand-alone and the fully integrated clinic. Qualitative data suggested that many clients at HIV-only sites felt greater confidentiality knowing that those around them were positive, and support was gained from other HIV care clients. Confidentiality was maintained in various ways, even in stand-alone sites, through separate waiting areas for HIV testing and HIV treatment, and careful clinic and room labelling. Conclusions The relationship between model of care and stigma was complex, and the hypothesis that stigma is higher at stand-alone sites did not hold true in this high prevalence setting. Policy-makers should ensure that service integration does not increase stigma, in particular within partially integrated models of care.

Church, Kathryn; Wringe, Alison; Fakudze, Phelele; Kikuvi, Joshua; Simelane, Dudu; Mayhew, Susannah H

2013-01-01

177

A hybrid wind-photovoltaic power supply for a telecommunication system  

Microsoft Academic Search

This paper describes a stand-alone hybrid wind-photovoltaic power plant for a remote telecommunication system located on the Black Sea Coast. First, the wind and solar potential of the site and also the load profile were assessed. It is shown that the two energy sources are complementary, so it is possible to have a better energy utilization factor. As a consequence,

Marian Vilsan; Irina Nita

1997-01-01

178

SAPT units turn-on in an interference-dominant environment. [Stand Alone Pressure Transducer  

NASA Technical Reports Server (NTRS)

A stand alone pressure transducer (SAPT) is a credit-card-sized smart pressure sensor inserted between the tile and the aluminum skin of a space shuttle. Reliably initiating the SAPT units via RF signals in a prelaunch environment is a challenging problem. Multiple-source interference may exist if more than one GSE (ground support equipment) antenna is turned on at the same time to meet the simultaneity requirement of 10 ms. A polygon model for orbiter, external tank, solid rocket booster, and tail service masts is used to simulate the prelaunch environment. Geometric optics is then applied to identify the coverage areas and the areas which are vulnerable to multipath and/or multiple-source interference. Simulation results show that the underside areas of an orbiter have incidence angles exceeding 80 deg. For multipath interference, both sides of the cargo bay areas are found to be vulnerable to a worst-case multipath loss exceeding 20 dB. Multiple-source interference areas are also identified. Mitigation methods for the coverage and interference problem are described. It is shown that multiple-source interference can be eliminated (or controlled) using the time-division-multiplexing method or the time-stamp approach.

Peng, W.-C.; Yang, C.-C.; Lichtenberg, C.

1990-01-01

179

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

PubMed Central

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.

Marchi, Luis; Abdala, Nitamar; Oliveira, Leonardo; Amaral, Rodrigo; Coutinho, Etevaldo; Pimenta, Luiz

2012-01-01

180

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

PubMed

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. PMID:22303335

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

2011-01-01

181

Serial endovascular embolization as stand-alone treatment of a sacral aneurysmal bone cyst.  

PubMed

Aneurysmal bone cysts (ABCs) are destructive cystic lesions of the bone and are common in children. They are expansile in nature and, therefore, may become symptomatic. These have traditionally been treated surgically; but recently, endovascular embolization has shown promise as a stand-alone therapy. The authors describe a case of an ABC highlighting the effectiveness and efficiency of endovascular treatment. A 16-year-old boy was referred for a 4-month history of radiating back pain and urinary hesitancy. Findings from his neurological examination were normal, but he had problems ambulating because of pain. Magnetic resonance imaging and CT scanning showed a cystic mass in the sacrum; a biopsy was performed and diagnosis of ABC was confirmed. Treatment options were then discussed with the family. The patient underwent 2 endovascular embolizations in approximately 1 month: Onyx 18 was involved in the first session, and N-butyl cyanoacrylate glue was used in the second session. After the first treatment, the patient experienced a dramatic decrease in pain and concomitant improvement in function. The patient went from being mildly symptomatic after the first treatment to completely asymptomatic after the second treatment. Clinical and radiographic follow-up obtained at 2, 6, and 18 months after initial treatment revealed the patient to be asymptomatic with progressive ossification. Endovascular treatment can be effective in treating symptomatic cases of ABC in which surgery would carry significant risk. Selective arterial embolization can promote sclerosis and result in an immediate and significant decrease in pain. PMID:24328760

Doss, Vinodh T; Weaver, Jason; Didier, Scott; Arthur, Adam S

2014-02-01

182

Casework application of a stand-alone pentaplex assay of extended-ESS STRs.  

PubMed

Using a stand-alone pentaplex comprising two standard-length short tandem repeats (STRs): D12S391 and D1S1656 plus three mini-STRs: D2S441, D10S1248 and D22S1045, all recently adopted to extend the European Standard Set (ESS) STRs, we have examined the genotyping performance of the new markers in 111 challenging casework samples. Although commercial kits now combine the five new STRs with existing core loci, we found the ESS-pentaplex we developed in-house performed better than both MiniFiler (comprising eight miniaturized STRs) and the NGM kit that includes the new STRs in a 15-marker multiplex. Our findings suggest at least part of the improved sensitivity of recently available ESS STRs can be attributed to the loci themselves as well as applying long-standing, robust primer designs that were first designed for the extended ESS markers by the laboratories that originally developed them. Therefore the ESS-pentaplex provides an ideal adjunct to Identifiler or MiniFiler to allow laboratories to assess the new STRs alongside existing standard loci, measure performance with challenging material and generate population frequency data ahead of a final decision on which additional STRs will extend the reconfigured CODIS core set. PMID:23380509

Barbaro, A; Fernandez-Formoso, L; Phillips, C; Carracedo, A; Lareu, M V

2013-07-01

183

Vector controlled induction machines for stand-alone wind energy applications  

Microsoft Academic Search

This paper describes the system and control structures for vector controlled induction generators used for variable speed, wind energy conversion (WEC) systems. The paper focuses on WEC systems feeding an isolated load or weak grid since for such systems the generated voltage and power flow must be regulated by the WEC system itself and the control structures are not trivial.

R. S. Pena; R. J. Cardenas; G. M. Asher; J. C. Clare

2000-01-01

184

Water Wisdom: 23 Stand-Alone Activities on Water Supply and Water Conservation for High School Students. 2nd Edition.  

ERIC Educational Resources Information Center

This water conservation education program for high schools consists of both stand-alone activities and teacher support materials. Lessons are divided into six broad categories: (1) The Water Cycle; (2) Water and Society; (3) Keeping Water Pure; (4) Visualizing Volumes; (5) The Economics of Water Use; and (6) Domestic Water Conservation. The…

Massachusetts State Water Resources Authority, Boston.

185

Review of stand-alone photovoltaic application projects sponsored by US DOE and US AID  

NASA Technical Reports Server (NTRS)

Experience with dc photovoltaic systems (without backup power) and ranging in output from 23 to 3,500 peak watts, in a wide range of environmental conditions and with a wide range of insolation, is described. Cooperation of NASA with other government agencies resulted in the installation of an air pollution monitor in New Jersey, a seismic sensor in Hawaii, power for lookout towers in national forests in California, an electric power system for a Papago Indian village in Arizona, and a power system for a grain mill and water pump in Tangaye, Upper Volta. Significant operational results are discussed and system reliability is assessed for the 20 experimental systems installed since 1976. Additional systems to be installed overseas are highlighted, and economic factors are considered.

Bifano, W. J.

1981-01-01

186

Power Systems Integration Laboratory (Fact Sheet)  

SciTech Connect

This fact sheet describes the purpose, lab specifications, applications scenarios, and information on how to partner with NREL's Power Systems Integration Laboratory at the Energy Systems Integration Facility. At NREL's Power Systems Integration Laboratory in the Energy Systems Integration Facility (ESIF), research focuses on developing and testing large-scale distributed energy systems for grid-connected, stand-alone, and microgrid applications. The laboratory can accommodate large power system components such as inverters for photovoltaic (PV) and wind systems, diesel and natural gas generators, battery packs, microgrid interconnection switchgear, and vehicles. Closely coupled with the research electrical distribution bus at the ESIF, the Power Systems Integration Laboratory will offer power testing capability of megawatt-scale DC and AC power systems, as well as advanced hardware-in-the-loop and model-in-the-loop simulation capabilities. Thermal heating and cooling loops and fuel also allow testing of combined heating/cooling and power systems (CHP).

Not Available

2011-10-01

187

Biomechanical comparison of two different concepts for stand alone anterior lumbar interbody fusion  

PubMed Central

Segmental instability in degenerative disc disease is often treated with anterior lumbar interbody fusion (ALIF). Current techniques require an additional posterior approach to achieve sufficient stability. The test device is an implant which consists of a PEEK-body and an integrated anterior titanium plate hosting four diverging locking screws. The test device avoids posterior fixation by enhancing stability via the locking screws. The test device was compared to an already established stand alone interbody implant in a human cadaveric three-dimensional stiffness test. In the biomechanical test, the L4/5 motion segment of 16 human cadaveric lumbar spines were isolated and divided into two test groups. Tests were performed in flexion, extension, right and left lateral bending, right and left axial rotation. Each specimen was tested in native state first, then a discectomy was performed and either of the test implants was applied. Finite element analysis (FE) was also performed to investigate load and stress distribution within the implant in several loading conditions. The FE models simulated two load cases. These were flexion and extension with a moment of 5 Nm. The biomechanical testing revealed a greater stiffness in lateral bending for the SynFix-LR™ compared to the established implant. Both implants showed a significantly higher stiffness in all loading directions compared to the native segment. In flexion loading, the PEEK component takes on most of the load, whereas the majority of the extension load is put on the screws and the screw–plate junction. Clinical investigation of the test device seems reasonable based on the good results reported here.

Gerlach, R.; Schar, B.; Cain, C. M. J.; Achatz, W.; Pflugmacher, R.; Haas, N. P.; Kandziora, F.

2008-01-01

188

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications  

DOEpatents

An illumination source is disclosed 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.

Tam, S.W.

1998-06-16

189

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications  

DOEpatents

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.

Tam, Shiu-Wing (Downers Grove, IL)

1997-01-01

190

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications  

DOEpatents

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.

Tam, Shiu-Wing (Downers Grove, IL)

1998-01-01

191

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications  

DOEpatents

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.

Tam, S.W.

1997-02-25

192

Development of a low-cost polymethylmethacrylate stand-alone cervical cage: technical note.  

PubMed

Background and Study Aims?Stand-alone cervical cages aim to provide primary stability, yield solid fusion in the long-term course, and maintain physiologic alignment. However, many implants designed for these purposes fail in achieving these goals. Following implantation, relatively high rates of cage subsidence and failure of disc height maintenance may lead to cervical kyphosis and poor alignment of the cervical spine. At the same time, costs for cage implantation are relatively high compared with their unfavorable radiologic performance. Thus the aim of the study was to develop and test mechanically a low-cost polymethylmethacrylate (PMMA) cage with similar mechanical and procedural properties compared with a commercial polyetheretherketone (PEEK) cage. Material and Methods?Following determination of the cage design, a casting mold was developed for the production of PMMA cages. Nine cages were produced and compared with nine PEEK cages using static compression tests for 0 and 45 degrees according to the recommendations of the American Society for Testing and Materials. Mean compressive yield strength, mean yield displacement, mean tensile strength, and mean stiffness were determined. Results?At 0 degrees axial compression, the mean compressive yield strength, mean displacement, and mean tensile strength of the PMMA cage was significantly higher compared with the PEEK cage (p?

Brenke, Christopher; Pott, Peter; Schwarz, Markus L; Schmieder, Kirsten; Barth, Martin

2014-07-01

193

Test Bed for Studying Real-Time Simulation and Control for Shipboard Power Systems  

Microsoft Academic Search

This paper discusses a real-time test bed which has been developed to study real-time issues during the design of new control and stability methodologies for stand alone power systems, such as naval shipboard power systems. The test bed uses the National Instrument embedded tool suite (ETS) and the compact reconfigurable I\\/O (cRIO) powered by field programmable gate array (FPGA) technology

Karen L. Butler-Purry; Gayatri R. Damle; N. D. R. Sarma; Fabian Uriarte; Derek Grant

2007-01-01

194

Validation of the kinetic model for predicting the composition of chlorinated water discharged from power plant cooling systems  

Microsoft Academic Search

The purpose of this report is to present a validation of a previously described kinetic model which was developed to predict the composition of chlorinated fresh water discharged from power plant cooling systems. The model was programmed in two versions: as a stand-alone program and as a part of a unified transport model developed from consistent mathematical models to simulate

Lietzke

1977-01-01

195

Energy storage considerations for a stand-alone wave energy plant  

Microsoft Academic Search

Despite several wave energy plants based on oscillating water column concept having been tested worldwide, wave energy has not yet gained popularity as a renewable energy source because of highly intermittent nature of available wave power. Still maintaining a constant voltage and frequency at the output, requires embedding of energy storage devices of sufficient capacity into the system. As the

S. Muthukumar; S. Kakumanu; S. Sriram; V. Jayashankar

2005-01-01

196

MONITORING SYSTEM OF LARGE POWER TRANSFORMERS BASED ON UP - TO - DATE INFORMATION TECHNOLOGY  

Microsoft Academic Search

Large power transformers belong to the most valuable and important assets in electrical power systems. The ageing of the used oil\\/paper-insulation primarily depends on the hot-spot temperature of the solid insulation system. Hence it is the dominant factor limiting the lifetime of the transformer. Therefore in 1996 a prototype of a stand alone thermal monitoring system was developed and installed

Enzo CARDILLO; Kurt FESER

197

A mobile renewable house using PV\\/wind\\/fuel cell hybrid power system  

Microsoft Academic Search

A photovoltaic\\/wind\\/fuel cell hybrid power system for stand-alone applications is proposed and demonstrated with a mobile house. This concept shows that different renewable sources can be used simultaneously to power off-grid applications. The presented mobile house can produce sufficient power to cover the peak load. Photovoltaic and wind energy are used as primary sources and a fuel cell as backup

Mehmed Eroglu; Erkan Dursun; Suat Sevencan; Junseok Song; Suha Yazici; Osman Kilic

2011-01-01

198

Stirling Machines for High-Efficiency and Ecologically Clean Stand-Alone Energy Supply Systems  

Microsoft Academic Search

Gas regenerative machines operating on forward and reverse Stirling cycles (Stirling machines) [1] are the most promising ecologically clean energy converters which meet the requirements of energy generation with minimum use of material resources. Structurally, Stirling machines contain in a single unit a compressor, an expander, and heat-exchanging devices (heater or condenser, regenerator, and refrigerator). The working medium used is

N. G. Kirillov

2000-01-01

199

Dynamic modeling and control of a cascaded active battery\\/ultra-capacitor based vehicular power system  

Microsoft Academic Search

This paper presents an active hybrid battery\\/ultra-capacitor based vehicular power system. The stand alone battery system may not be sufficient to satisfy peak demand periods during transients in HEVs. An ultra-capacitor bank can supply or recapture a large burst of power since it can be used with high C-rates. Active battery\\/ultra-capacitor hybrid model provides a better solution in terms of

Omer Onar; Alireza Khaligh

2008-01-01

200

Performance of a stand-alone wind-electric ice maker for remote villages  

SciTech Connect

Two ice makers in the 1.1 metric tons per 24 hours (1.2 tons per day) size range were tested to determine their performance when directly coupled to a variable-frequency wind turbine generator. Initial tests were conducted using a dynamometer to simulate to wind to evaluate whether previously determined potential problems were significant and to define basic performance parameters. Field testing in Norman, Oklahoma, was completed to determine the performance of one of the ice makers under real wind conditions. As expected, the ice makers produced more ice at a higher speed than rated, and less ice at a lower speed. Due to the large start-up torque requirement of reciprocating compressors, the ice making system experienced a large start-up current and corresponding voltage drop which required a larger wind turbine that expected to provide the necessary current and voltage. Performance curves for ice production and power consumption are presented. A spreadsheet model was constructed to predict ice production at a user-defined site given the wind conditions for that location. Future work should include long-term performance tests and research on reducing the large start-up currents the system experiences when first coming on line.

Davis, H.C. [National Renewable Energy Lab., Golden, CO (United States); Brandemuehl, M.J. [University of Colorado, Boulder, CO (United States). Joint Center for Energy Management; Bergey, M.L.S. [Bergey Windpower Co., Norman, OK (United States)

1995-01-01

201

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

PubMed Central

Background 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. Results 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. Conclusion 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.

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

2009-01-01

202

Optimizing Science Payloads for Stand-Alone Operation on the Lunar Surface in the Next Decades  

NASA Astrophysics Data System (ADS)

We demonstrate that alternative thermal design and components for state-of-the-art science packages can meet and potentially exceed the power and mass constraints of earlier packages without requiring the use of Pu238 based radiothermal generators.

Clark, P. E.; Lewis, R.; Millar, P. S.; Yeh, P. S.; Lorenz, J.; Feng, S.; Powell, W.; Beaman, R.; Brown, K.; Leshin, L.

2008-07-01

203

A wind-powered seawater reverse-osmosis system without batteries  

Microsoft Academic Search

The development of small-scale stand-alone desalination systems is important to communities on islands and in isolated inland areas. In such places, electricity supplies are often expensive and unreliable, while the wind resource is abundant. The system presented here comprises a 2.2 kW wind turbine generator powering a variable-flow Reverse osmosis (RO) desalination unit. It is highly efficient, rugged, built with

Marcos S. Miranda; David Infield

2003-01-01

204

Design and fabrication of a photovoltaic power system for the Papago Indian village of Schuchuli (Gunsight), Arizona  

NASA Technical Reports Server (NTRS)

A stand alone photovoltaic power system for installation in the Papago Indian village of Schuchuli is being designed and fabricated to provide electricity for village water pumping and basic domestic needs. The system will consist of a 3.5 kW (peak) photovoltaic array; controls, instrumentations, and storage batteries located in an electrical equipment building and a 120 volt dc village distribution network. The system will power a 2 HP dc electric motor.

Bifano, W. J.; Ratajczak, A. F.; Ice, W. J.

1978-01-01

205

Modeling of photovoltaic power plants  

Microsoft Academic Search

This work deals with methods of design for the appropriate selection of a stand-alone photovoltaic power system for residential application in the absence of utility power supply. For a prescribed power demand design includes the determination of required number of photovoltaic (PV) panels and the proper total size of batteries to store part of the day collected energy for night

Zakaria Anwar Zakaria; Bai-Chao Chen; Mohammed Osman Hassan

2008-01-01

206

Control of digital AVR in stand alone generator for improved dynamic characteristics  

Microsoft Academic Search

AC brushless generator combined diesel engine is much used for the power supply equipment due to the stability and maintenance. At the starting of AC brushless generator, the output voltage from residual flux of a generator is very small. So, the AVR(automatic voltage regulator) should wake up with the low starting voltage. And the starting voltage is very low, it's

Dong-Hee Lee; Tae-Hyoung Kim; Jin-Woo Ahn

2008-01-01

207

Automatic management of energy flows of a stand-alone renewable energy supply with hydrogen support  

Microsoft Academic Search

This work deals with the design and construction of an automation system for controlling the electric energy flows that take place at the continuous current bus (DC Bus) of a wind–solar system with hydrogen support. The automation system is based on a Siemens PLC s7_313C_2DP. This PLC was equipped with a Micro Memory Card (MMC) of 2MB in order to

M. Calderón; A. J. Calderón; A. Ramiro; J. F. González

2010-01-01

208

Thermoelectric generator and solid-state battery for stand-alone microsystems  

NASA Astrophysics Data System (ADS)

This paper presents a thermoelectric (TE) generator and a solid-state battery for powering microsystems. Prototypes of TE generators were fabricated and characterized. The TE generator is a planar microstructure based on thin films of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3), which were deposited using co-evaporation. The measurements on selected samples of Bi2Te3 and Sb2Te3 thin films indicated a Seebeck coefficient in the range of 90-250 µV K-1 and an in-plane electrical resistivity in the range of 7-17 µ? m. The measurements also showed TE figures-of-merit, ZT, at room temperatures (T = 300 K) of 0.97 and 0.56, for thin films of Bi2Te3 and Sb2Te3, respectively (equivalent to a power factor, PF, of 4.87 mW K-2 m-1 and 2.81 mW K-2 m-1). The solid-state battery is based on thin films of: an anode of tin dioxide (SnO2), an electrolyte of lithium phosphorus oxynitride (LixPOyNz, known as LiPON) and a cathode of lithium cobaltate (LiCoO2, known as LiCO), which were deposited using the reactive RF (radio-frequency) sputtering. The deposition and characterization results of these thin-films layers are also reported in this paper.

Carmo, J. P.; Ribeiro, J. F.; Silva, M. F.; Goncalves, L. M.; Correia, J. H.

2010-08-01

209

Improved Wrede Stand-Alone ORC (Organic Rankine-Cycle) Solar Water Pump with Tracking Concentrators.  

National Technical Information Service (NTIS)

This paper describes the Wrede organic Rankine-cycle solar water pump employing tracking parabolic troughs. System principles and improvements introduced with the fifth-generation pump-unit and the concentrators are briefly discussed. Previous field tests...

P. D. Lund T. C. W. Wrede

1984-01-01

210

Hybrid solar\\/wind power system probabilistic modelling for long-term performance assessment  

Microsoft Academic Search

This paper presents a probabilistic approach based on the convolution technique to assess the long-term performance of a hybrid solar–wind power system (HSWPS) for both stand-alone and grid-linked applications. To estimate energy performance of HSWPS the reliability analysis is performed by the use of the energy index of reliability (EIR) directly related to energy expected not supplied (EENS). Analytical expressions

G. Tina; S. Gagliano; S. Raiti

2006-01-01

211

Alignment of the CMS silicon strip tracker during stand-alone commissioning  

Microsoft Academic Search

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

W. Adam; T. Bergauer; M. Dragicevic; M. Friedl; R. Frühwirth; S. Hänsel; J. Hrubec; M. Krammer; M. Oberegger; M. Pernicka; S. Schmid; R. Stark; H. Steininger; D. Uhl; W. Waltenberger; E. Widl; P. Van Mechelen; M. Cardaci; W. Beaumont; E. de Langhe; E. A. de Wolf; E. Delmeire; M. Hashemi; O. Bouhali; O. Charaf; B. Clerbaux; J.-P. Dewulf; S. Elgammal; G. Hammad; G. de Lentdecker; P. Marage; C. Vander Velde; P. Vanlaer; J. Wickens; V. Adler; O. Devroede; S. DeWeirdt; J. D'Hondt; R. Goorens; J. Heyninck; J. Maes; Matthias Ulrich Mozer; S. Tavernier; L. Van Lancker; P. Van Mulders; I. Villella; C. Wastiels; J.-L. Bonnet; G. Bruno; B. DeCallatay; B. Florins; A. Giammanco; G. Gregoire; Th Keutgen; D. Kcira; V. Lemaitre; D. Michotte; O. Militaru; K. Piotrzkowski; L. Quertermont; V. Roberfroid; X. Rouby; D. Teyssier; E. Daubie; E. Anttila; S. Czellar; P. Engström; J. Härkönen; V. Karimäki; J. Kostesmaa; A. Kuronen; T. Lampén; T. Lindén; P.-R. Luukka; T. Mäenää; S. Michal; E. Tuominen; J. Tuominiemi; M. Ageron; G. Baulieu; A. Bonnevaux; G. Boudoul; E. Chabanat; E. Chabert; R. Chierici; D. Contardo; R. Della Negra; T. Dupasquier; G. Gelin; N. Giraud; G. Guillot; N. Estre; R. Haroutunian; N. Lumb; S. Perries; F. Schirra; B. Trocme; S. Vanzetto; J.-L. Agram; R. Blaes; F. Drouhin; J.-P. Ernenwein; J.-C. Fontaine; J.-D. Berst; J.-M. Brom; F. Didierjean; U. Goerlach; P. Graehling; L. Gross; J. Hosselet; P. Juillot; A. Lounis; C. Maazouzi; C. Olivetto; R. Strub; P. Van Hove; G. Anagnostou; R. Brauer; H. Esser; L. Feld; W. Karpinski; K. Klein; C. Kukulies; J. Olzem; A. Ostapchuk; D. Pandoulas; G. Pierschel; F. Raupach; S. Schael; G. Schwering; D. Sprenger; M. Thomas; M. Weber; B. Wittmer; M. Wlochal; F. Beissel; E. Bock; G. Flugge; C. Gillissen; T. Hermanns; D. Heydhausen; D. Jahn; G. Kaussen; A. Linn; L. Perchalla; M. Poettgens; O. Pooth; A. Stahl; M. H. Zoeller; P. Buhmann; E. Butz; G. Flucke; R. Hamdorf; J. Hauk; R. Klanner; U. Pein; P. Schleper; G. Steinbrück; P. Blüm; W. DeBoer; A. Dierlamm; G. Dirkes; M. Fahrer; M. Frey; A. Furgeri; F. Hartmann; S. Heier; K.-H. Hoffmann; J. Kaminski; B. Ledermann; T. Liamsuwan; S. Müller; Th Müller; F.-P. Schilling; H.-J. Simonis; P. Steck; V. Zhukov; P. Cariola; G. DeRobertis; R. Ferorelli; L. Fiore; M. Preda; G. Sala; L. Silvestris; P. Tempesta; G. Zito; D. Creanza; N. DeFilippis; M. DePalma; D. Giordano; G. Maggi; N. Manna; S. My; G. Selvaggi; S. Albergo; M. Chiorboli; S. Costa; M. Galanti; N. Giudice; N. Guardone; F. Noto; R. Potenza; M. A. Saizu; V. Sparti; C. Sutera; A. Tricomi; C. Tuvè; M. Brianzi; C. Civinini; F. Maletta; F. Manolescu; M. Meschini; S. Paoletti; G. Sguazzoni; B. Broccolo; V. Ciulli; R. D'Alessandro E. Focardi; S. Frosali; C. Genta; G. Landi; P. Lenzi; A. Macchiolo; N. Magini; G. Parrini; E. Scarlini; G. Cerati; P. Azzi; N. Bacchetta; A. Candelori; T. Dorigo; A. Kaminsky; S. Karaevski; V. Khomenkov; S. Reznikov; M. Tessaro; D. Bisello; M. DeMattia; P. Giubilato; M. Loreti; S. Mattiazzo; M. Nigro; A. Paccagnella; D. Pantano; N. Pozzobon; M. Tosi; G. M. Bilei; B. Checcucci; L. Fanò; L. Servoli; F. Ambroglini; E. Babucci; D. Benedetti; M. Biasini; B. Caponeri; R. Covarelli; M. Giorgi; P. Lariccia; G. Mantovani; M. Marcantonini; V. Postolache; A. Santocchia; D. Spiga; G. Bagliesi; G. Balestri; L. Berretta; S. Bianucci; T. Boccali; F. Bosi; F. Bracci; R. Castaldi; M. Ceccanti; R. Cecchi; C. Cerri; A. S. Cucoanes; R. Dell'Orso; D. Dobur; S. Dutta; A. Giassi; S. Giusti; D. Kartashov; A. Kraan; T. Lomtadze; G. A. Lungu; G. Magazzù; P. Mammini; F. Mariani; G. Martinelli; A. Moggi; F. Palla; F. Palmonari; G. Petragnani; A. Profeti; F. Raffaelli; D. Rizzi; G. Sanguinetti; S. Sarkar; D. Sentenac; A. T. Serban; A. Soldani; P. Spagnolo; R. Tenchini; S. Tolaini; A. Venturi; P. G. Verdini; M. Vos; L. Zaccarelli; C. Avanzini; A. Basti; L. Benucci; A. Bocci; U. Cazzola; F. Fiori; S. Linari; M. Massa; A. Messineo; G. Segneri; G. Tonelli; P. Azzurri; J. Bernardini; L. Borrello; F. Calzolari; L. Foà; S. Gennai; F. Ligabue; G. Petrucciani; A. Rizzi; Z. Yang; F. Benotto; N. Demaria; F. Dumitrache; R. Farano; M. A. Borgia; R. Castello; M. Costa; E. Migliore; A. Romero; D. Abbaneo; M. Abbas; I. Ahmed; I. Akhtar; E. Albert; C. Bloch; H. Breuker; S. Butt; O. Buchmuller; A. Cattai; C. Delaere; M. Delattre; L. M. Edera; M. Eppard; M. Gateau; K. Gill; A.-S. Giolo-Nicollerat; R. Grabit; A. Honma; M. Huhtinen; K. Kloukinas; J. Kortesmaa; L. J. Kottelat; N. Leonardo; C. Ljuslin; M. Mannelli; L. Masetti; A. Marchioro; S. Mersi; L. Mirabito; J. Muffat-Joly; A. Onnela; C. Paillard; I. Pal; J. F. Pernot; P. Petagna; C. Piccut; M. Pioppi; H. Postema; R. Ranieri; D. Ricci; G. Rolandi; F. Ronga; C. Sigaud; A. Syed; P. Siegrist; P. Tropea; J. Troska; A. Tsirou; M. Vander Donckt; F. Vasey; E. Alagoz; C. Amsler; V. Chiochia; C. Regenfus; P. Robmann; J. Rochet

2009-01-01

212

Continuous stand-alone controllable aerosol/cloud droplet dryer for atmospheric sampling  

NASA Astrophysics Data System (ADS)

We describe a general-purpose dryer designed for continuous sampling of atmospheric aerosol, where a specified relative humidity (RH) of the sample flow (lower than the atmospheric humidity) is required. It is often prescribed to measure the properties of dried aerosol, for instance for monitoring networks. The specific purpose of our dryer is to dry cloud droplets (maximum diameter approximately 25 ?m, highly charged, up to 5 × 102 charges). One criterion is to minimise losses from the droplet size distribution entering the dryer as well as on the residual dry particle size distribution exiting the dryer. This is achieved by using a straight vertical downwards path from the aerosol inlet mounted above the dryer, and removing humidity to a dry, closed loop airflow on the other side of a semi-permeable GORE-TEX membrane (total area 0.134 m2). The water vapour transfer coefficient, k, was measured to be 4.6 × 10-7 kg m-2 s-1% RH-1 in the laboratory (temperature 294 K) and is used for design purposes. A net water vapour transfer rate of up to 1.2 × 10-6 kg s-1 was achieved in the field. This corresponds to drying a 5.7 L min-1 (0.35 m3 h-1) aerosol sample flow from 100% RH to 27% RH at 293 K (with a drying air total flow of 8.7 L min-1). The system was used outdoors from 9 May until 20 October 2010, on the mountain Brocken (51.80° N, 10.67° E, 1142 m a.s.l.) in the Harz region in central Germany. Sample air relative humidity of less than 30% was obtained 72% of the time period. The total availability of the measurement system was >94% during these five months.

Sjogren, S.; Frank, G. P.; Berghof, M. I. A.; Martinsson, B. G.

2013-02-01

213

Emerging technologies: polymer-free phospholipid encapsulated sirolimus nanocarriers for the controlled release of drug from a stent-plus-balloon or a stand-alone balloon catheter.  

PubMed

Drug-eluting stents have proven to be effective in reducing the risk of late restenosis. In order to achieve a controlled and prolonged release of the antiproliferative agent, current drug-eluting stents utilise various biodegradable as well as non-erodible polymeric blends to coat the stent surface and to serve as drug carriers. The utilisation of polymeric compounds in current drug-eluting stents may eventually limit their performance as well as their clinical applicability due to the potential induction of undesirable local reactions. The development of alternative, polymer-free drug carriers has the potential to overcome some of the limitations of current drug-eluting stent formulations. Moreover, improvements in drug carriers may also result in an expansion of the technological possibilities for other intravascular drug delivery systems, such as metal-free or even implant-free solutions. This article describes the structure and the preclinical validation profile of a novel phospholipid encapsulated sirolimus nanocarrier, used as a coating in two formulations: a coronary stent-plus-balloon system and a stand-alone balloon catheter. The nanoparticles provided a stable, even and homogenous coating to the devices in both formulations. Dose-finding studies allowed the most appropriate identification of the best nanoparticle structure associated with an extremely efficient transfer of drug to all layers of the vessel wall, achieving high tissue concentrations that persisted days after the application, with low systemic drug leaks. PMID:23685303

Lemos, Pedro A; Farooq, Vasim; Takimura, Celso K; Gutierrez, Paulo S; Virmani, Renu; Kolodgie, Frank; Christians, Uwe; Kharlamov, Alexander; Doshi, Manish; Sojitra, Prakash; van Beusekom, Heleen M M; Serruys, Patrick W

2013-05-20

214

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

PubMed

Object 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 placement of stand-alone Trabecular Metal cages in these patients. Methods The authors performed a retrospective analysis of 26 patients with recurrent disc herniations treated with stand-alone posterior lumbar interbody fusion (PLIF) with Trabecular Metal cages. At 1 year patients were evaluated using the Roland Morris Disability Questionnaire (RMDQ) and a visual analog scale (VAS) for back and leg pain. Furthermore, Likert scores of perceived recovery and satisfaction with the treatment were recorded. Lumbar spine radiographs after 1 year were compared with postoperative radiographs to measure subsidence. Stability of the operated segment was assessed using dynamic radiography. Results The patient group consisted of 26 patients (62% male) with a mean age of 45.7 ± 11.4 years (± SD). Patients had a history of 1 (31%), 2 (42%), or more (27%) discectomies at the same level. The mean follow-up period was 15.3 ± 7.3 months. At follow-up the mean VAS score for pain in the affected leg was 36.7 ± 27.9. The mean VAS score for back pain was 42.5 ± 30.2. The mean RMDQ score at follow-up was 9.8 ± 6.2. Twelve (46%) of the 26 patients had a global perceived good recovery. With respect to treatment satisfaction, 18 patients (69%) were content or very content with the operation and would recommend it. Disc height was increased immediately postoperatively, and at the 1-year follow-up it was still significantly higher compared with the preoperative height (mean 41% ± 38.7%, range -25.7 to 126.8, paired t-test, both p < 0.001), although a mean of 7.52% ± 11.6% subsidence occurred (median 2.0% [interquartile range 0.0%-10.9%], p < 0.003). No significant correlation between subsidence and postoperative back pain was found (Spearman's rho -0.2, p = 0.459). Flexion-extension radiographs showed instability in 1 patient. Conclusions Although only 46% of patients reported a good recovery with significant reductions in back and leg pain, 85% of patients reported at least some benefit from the operation, and a marked improvement in working status at follow-up was noted. In view of previously published poor results of instrumented lumbar fusion for patients with failed back surgery syndrome, the present data indicate that Trabecular Metal interbody fusion cages can be used in a stand-alone fashion and should not always need supplemental posterior fixation in patients with recurrent disc herniation without spinal instability, although a long-term follow-up study is warranted. PMID:24678638

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

2014-06-01

215

An explosively driven high-power microwave pulsed power system.  

PubMed

The increased popularity of high power microwave systems and the various sources to drive them is the motivation behind the work to be presented. A stand-alone, self-contained explosively driven high power microwave pulsed power system has been designed, built, and tested at Texas Tech University's Center for Pulsed Power and Power Electronics. The system integrates four different sub-units that are composed of a battery driven prime power source utilizing capacitive energy storage, a dual stage helical flux compression generator as the main energy amplification device, an integrated power conditioning system with inductive energy storage including a fast opening electro-explosive switch, and a triode reflex geometry virtual cathode oscillator as the microwave radiating source. This system has displayed a measured electrical source power level of over 5 GW and peak radiated microwaves of about 200 MW. It is contained within a 15 cm diameter housing and measures 2 m in length, giving a housing volume of slightly less than 39 l. The system and its sub-components have been extensively studied, both as integrated and individual units, to further expand on components behavior and operation physics. This report will serve as a detailed design overview of each of the four subcomponents and provide detailed analysis of the overall system performance and benchmarks. PMID:22380111

Elsayed, M A; Neuber, A A; Dickens, J C; Walter, J W; Kristiansen, M; Altgilbers, L L

2012-02-01

216

Kinome Render: a stand-alone and web-accessible tool to annotate the human protein kinome tree  

PubMed Central

Human protein kinases play fundamental roles mediating the majority of signal transduction pathways in eukaryotic cells as well as a multitude of other processes involved in metabolism, cell-cycle regulation, cellular shape, motility, differentiation and apoptosis. The human protein kinome contains 518 members. Most studies that focus on the human kinome require, at some point, the visualization of large amounts of data. The visualization of such data within the framework of a phylogenetic tree may help identify key relationships between different protein kinases in view of their evolutionary distance and the information used to annotate the kinome tree. For example, studies that focus on the promiscuity of kinase inhibitors can benefit from the annotations to depict binding affinities across kinase groups. Images involving the mapping of information into the kinome tree are common. However, producing such figures manually can be a long arduous process prone to errors. To circumvent this issue, we have developed a web-based tool called Kinome Render (KR) that produces customized annotations on the human kinome tree. KR allows the creation and automatic overlay of customizable text or shape-based annotations of different sizes and colors on the human kinome tree. The web interface can be accessed at: http://bcb.med.usherbrooke.ca/kinomerender. A stand-alone version is also available and can be run locally.

Barker, Jonathan

2013-01-01

217

Kinome Render: a stand-alone and web-accessible tool to annotate the human protein kinome tree.  

PubMed

Human protein kinases play fundamental roles mediating the majority of signal transduction pathways in eukaryotic cells as well as a multitude of other processes involved in metabolism, cell-cycle regulation, cellular shape, motility, differentiation and apoptosis. The human protein kinome contains 518 members. Most studies that focus on the human kinome require, at some point, the visualization of large amounts of data. The visualization of such data within the framework of a phylogenetic tree may help identify key relationships between different protein kinases in view of their evolutionary distance and the information used to annotate the kinome tree. For example, studies that focus on the promiscuity of kinase inhibitors can benefit from the annotations to depict binding affinities across kinase groups. Images involving the mapping of information into the kinome tree are common. However, producing such figures manually can be a long arduous process prone to errors. To circumvent this issue, we have developed a web-based tool called Kinome Render (KR) that produces customized annotations on the human kinome tree. KR allows the creation and automatic overlay of customizable text or shape-based annotations of different sizes and colors on the human kinome tree. The web interface can be accessed at: http://bcb.med.usherbrooke.ca/kinomerender. A stand-alone version is also available and can be run locally. PMID:23940838

Chartier, Matthieu; Chénard, Thierry; Barker, Jonathan; Najmanovich, Rafael

2013-01-01

218

Bimode uninterruptible power supply compatibility in renewable hybrid energy systems  

SciTech Connect

Inverters installed in renewable hybrid energy systems are typically used in a stand-alone mode to supply ac power to loads from battery storage when the engine-generator is not being used. Similarities in topology and in the performance requirements of the standby uninterruptible power supply (UPS) system and the hybrid system suggest the UPS could be used in hybrid energy systems. Another alternative to inverters with add-on charging circuits or standby UPS hardware is the Bimode UPS. The bimode UPS uses common circuitry and power components for dc to ac inversion and battery charging. It also provides an automatic and nearly instantaneous ac power transfer function when the engine-generator is started or stopped. The measured operating and transfer characteristics of a bimode UPS in a utility system and in a hybrid system are presented. The applicability of the bimode UPS to hybrid systems and its compatibility in a PV/engine-generator hybrid system are given.

Bower, W. (Sandia National Labs., Albuquerque, NM (USA)); O'Sullivan, G. (Abacus Controls, Inc., Somerville, NJ (USA))

1990-08-01

219

Maximum power throughput in the multiphase BLDC generator  

Microsoft Academic Search

This paper presents an advanced control technique for maximum power throughput of the multiphase Brushless DC (BLDC) generator of given design. In a generator of given rating, the weight and size of the system affect the fuel consumption directly. Therefore, maximum power density is one of the most important issues in a stand-alone generator. BLDC generator has high power density

H.-W. Lee; T. Kim; M. Ehsani

2004-01-01

220

Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States. (UNH)  

EPA Science Inventory

The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

221

Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States  

EPA Science Inventory

The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

222

Prospective clinical outcomes of revision fusion surgery in patients with pseudarthrosis after posterior lumbar interbody fusions using stand-alone metallic cages  

Microsoft Academic Search

Background contextPosterior lumbar interbody fusion (PLIF) is a popular method of arthrodesis for surgical treatment of instabilities and degenerative conditions of the spine. With the introduction of threaded titanium cage devices, surgeons began performing PLIF procedures using these cages as stand-alone devices. Complications have been reported, however, including pseudarthrosis with persistent pain. Outcomes after revision surgical treatment for these patients

Ezequiel H. Cassinelli; Corey Wallach; Brett Hanscom; Molly Vogt; James D. Kang

2006-01-01

223

100-kWp photovoltaic power system at Natural Bridges National Monument  

SciTech Connect

The Natural Bridges National Monument in southeastern Utah is the location of the world's largest solar photovoltaic power system. This system, which operates in a stand-alone mode without utility backup, supplies from 300 to 400 kWh/day of 60-Hz AC electrical energy to the diversified loads in the monument headquarters area. A diesel-powered generator serves as backup for the system. The solutions to a number of problems encountered in the design, fabrication, testing and early operation of the system are discussed.

Solman, F.J.; Helfrich, J.H.; Lyon, E.F.; Benoit, A.E.

1980-01-01

224

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

PubMed Central

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 without requiring prior bioinformatics skills.

2011-01-01

225

Subtask 3.12 - Small Power Systems  

SciTech Connect

The programmatic goal in advanced power systems is to develop small integrated waste treatment, water purification, and power systems in the range of 20 kW to 20 MW in cooperation with commercial vendors. These systems will be designed to incorporate the advanced technical capabilities of the Energy and Environmental Research Center (EERC) with the latest advancements in vendor-offered hardware and software. The primary objective for the work to be performed under this subtask is to develop a commercialization plan for small power systems, evaluate alternative design concepts, and select practical and economical designs for targeted development in upcoming years. A leading objective for the EERC will be to continue to form strong business partnerships with equipment manufacturers who can commercialize the selected power system and treatment design(s). FY95 activities were focused on collecting information from vendors and evaluating alternative design concepts. This year's activities began with the process of selecting one design for targeted development. A case study was performed to determine if the combination of water and waste treatment with power generation could improve the economics over a stand-alone power generation system.

Sprynczynatyk, C.; Schmidt, L.; Kurz, M.D.; Mann, M.D.; Kjelden, M.

1997-08-01

226

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

PubMed Central

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.

Chen, Shih-Hao; Tai, Ching-Lung; Lin, Chien-Yu; Hsieh, Pang-Hsing; Chen, Weng-Pin

2008-01-01

227

Operational Performance of the Photovoltaic-Powered Grain Mill and Water Pump at Tangaye, Upper Volta.  

National Technical Information Service (NTIS)

The first two years of operation of a stand alone photovoltaic (PV) power system for the village of Tangaye, Upper Volta in West Africa are described. The purpose of the experiment was to demonstrate that PV systems could provide reliable electrical power...

J. E. Martz A. F. Ratajczak R. Delombard

1982-01-01

228

The SDAWES project: an ambitious R&D prototype for wind-powered desalination  

Microsoft Academic Search

This paper describes the design and operational strategies of an ambitious prototype for a desalination system powered exclusively by wind energy. The system, installed on the island of Gran Canaria, was designed with several objectives in mind: (a) to determine experimentally the feasibility of the stand-alone operation of wind farms isolated from the conventional power grids and supplying energy for

José A. Carta; Jaime González; Vicente Subiela

2004-01-01

229

Energy balance associated with the use of a maximum power tracer in a 100-kW-peak power system  

SciTech Connect

Design of a stand-alone photovoltaic (PV) system which includes batteries for energy storage requires not only sizing the array power output and battery storage capacity to meet the load, but also fixing the number of battery cells placed in series relative to the number of PV cells in series in order to keep the battery voltage in the neighborhood of the array maximum-power-point voltage during operation. When a maximum-power-point tracker (MPPT) is interposed between the array and the battery, the design task is simplified. The decision to use an MPPT depends primarily on the operating efficiency of the device. The recent development at MIT Lincoln Laboratory of low-cost maximum-power-point trackers capable of efficiencies greater than 98% at the 3-kW level broadens the range of applications where an MPPT can be used to advantage. Hourly simulation results for the 100-kW-peak PV stand-alone system under construction at Natural Bridges National Monument in Utah are compared for the cases with and without maximum power tracking to quantify the advantage of MPPT implementation.

Bucciarelli, L.L.; Grossman, B.L.; Lyon, E.F.; Rasmussen, N.E.

1980-01-01

230

Stability of voltage and frequency control in distributed generation based on parallel-connected converters feeding constant power loads  

Microsoft Academic Search

In this paper stability and dynamic properties of voltage and frequency droop control of power electronic converters are investigated for a distributed generation system. Droop control is utilized to share active and reactive power among the source converters. The voltage and frequency controllers are designed so that stand-alone converter operation feeding constant power loads performs satisfactory. These controllers are adapted

P. Karlsson; J. Bjornstedt; M. Strom

2005-01-01

231

Anterior Cervical Discectomy and Fusion Using a Stand-Alone Polyetheretherketone Cage Packed with Local Autobone : Assessment of Bone Fusion and Subsidence  

PubMed Central

Objective It remains debatable whether cervical spine fusion cages should be filled with any kind of bone or bone substitute. Cortical and subcortical bone from the anterior and posterior osteophytes of the segment could be used to fill the cage. The purposes of the present study are to evaluate the clinical outcomes and radiological outcomes including bone fusion and subsidence that occurred after anterior cervical discectomy and fusion using a stand-alone cage packed with local autobone graft. Methods Thirty-one patients who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage packed with local autobone graft from July 2009 to december 2011 were enrolled in this study. Bone fusion was assessed by cervical plain radiographs and computed tomographic scan. Nonunion was evaluated according to the absence of bony bridge on computed tomographic scan. Subsidence was defined as a ?2 mm decrease of the interbody height at the final follow-up compared to that measured at the immediate postoperative period. Results Subsidence was observed in 7 patients (22.6%). Of 7 patients with subsidence greater 2 mm, nonunion was developed in 3. Three patients with subsidence greater 2 mm were related with endplate damage during intraoperative endplate preparation. Solid bone fusion was achieved in 28 out of 31 patients (90.3%). Conclusion With proper patient selection and careful endplate preparation, anterior cervical discectomy and fusion (ACDF) using a stand-alone PEEK cage packed with local autobone graft could be a good alternative to the standard ACDF techniques with plating.

Park, Jeong-Ill; Kim, Kyoung-Tae; Sung, Joo-Kyung

2013-01-01

232

Biomechanical comparison of anterior lumbar interbody fusion: stand-alone interbody cage versus interbody cage with pedicle screw fixation - a finite element analysis  

PubMed Central

Background Anterior lumbar interbody fusion (ALIF) followed by pedicle screw fixation (PSF) is used to restore the height of the intervertebral disc and provide stability. Recently, stand-alone interbody cage with anterior fixation has been introduced, which eliminates the need for posterior surgery. We compared the biomechanics of the stand-alone interbody cage to that of the interbody cage with additional PSF in ALIF. Methods A three-dimensional, non-linear finite element model (FEM) of the L2-5 segment was modified to simulate ALIF in L3-4. The models were tested under the following conditions: (1) intact spine, (2) destabilized spine, (3) with the interbody cage alone (type 1), (4) with the stand-alone cage with anterior fixation (SynFix-LR®; type 2), and (5) with type 1 in addition to PSF (type 3). Range of motion (ROM) and the stiffness of the operated level, ROM of the adjacent segments, load sharing distribution, facet load, and vertebral body stress were quantified with external loading. Results The implanted models had decreased ROM and increased stiffness compared to those of the destabilized spine. The type 2 had differences in ROM limitation of 8%, 10%, 4%, and 6% in flexion, extension, axial rotation, and lateral bending, respectively, compared to those of type 3. Type 2 had decreased ROM of the upper and lower adjacent segments by 3-11% and 3-6%, respectively, compared to those of type 3. The greatest reduction in facet load at the operated level was observed in type 3 (71%), followed by type 2 (31%) and type 1 (23%). An increase in facet load at the adjacent level was highest in type 3, followed by type 2 and type 1. The distribution of load sharing in type 2 (anterior:posterior, 95:5) was similar to that of the intact spine (89:11), while type 3 migrated posterior (75:25) to the normal. Type 2 reduced about 15% of the stress on the lower vertebral endplate compared to that in type 1. The stress of type 2 increased two-fold compared to the stress of type 3, especially in extension. Conclusions The stand-alone interbody cage can provide sufficient stability, reduce stress in adjacent levels, and share the loading distribution in a manner similar to an intact spine.

2013-01-01

233

Photovoltaic Power System and Power Distribution Demonstration for the Desert RATS Program  

NASA Technical Reports Server (NTRS)

A stand alone, mobile photovoltaic power system along with a cable deployment system was designed and constructed to take part in the Desert Research And Technology Studies (RATS) lunar surface human interaction evaluation program at Cinder Lake, Arizona. The power system consisted of a photovoltaic array/battery system. It is capable of providing 1 kW of electrical power. The system outputs were 48 V DC, 110 V AC, and 220 V AC. A cable reel with 200 m of power cable was used to provide power from the trailer to a remote location. The cable reel was installed on a small trailer. The reel was powered to provide low to no tension deployment of the cable. The cable was connected to the 220 V AC output of the power system trailer. The power was then converted back to 110 V AC on the cable deployment trailer for use at the remote site. The Scout lunar rover demonstration vehicle was used to tow the cable trailer and deploy the power cable. This deployment was performed under a number of operational scenarios, manned operation, remote operation and tele-robotically. Once deployed, the cable was used to provide power, from the power system trailer, to run various operational tasks at the remote location.

Colozza, Anthony; Jakupca, Ian; Mintz, Toby; Herlacher, Mike; Hussey, Sam

2012-01-01

234

Dichotomic algorithm to drive a wind mill in association with PV panels for stand alone electrical energy production  

Microsoft Academic Search

This paper proposes an optimal energy recovery method in the case of a windmill, photovoltaic panels array and lead-acid batteries used for an islanded DC network. From renewable energy characteristics and especially power rates, we propose to drive the windmill and the PV array at optimal power by respectively a dichotomic algorithm and Fuzzy Logic Controller. The wind turbine drives

Oumar BA; Daniel DEPERNET; Pape Alioune NDIAYE; Alain BERTHON

2009-01-01

235

Design and sizing of a stand-alone recharging point for battery electrical vehicles using photovoltaic energy  

Microsoft Academic Search

A battery electric vehicle (BEV) is a widely used type of electric vehicle (EV) that uses chemical energy stored in rechargeable battery packs. BEVs are becoming more attractive with the advancement of new battery technology that has higher power and energy density and allowing matching the requested autonomy and vehicle dynamics. BEV batteries are recharged on board vehicles using either

M. Becherif; M. Y. Ayad; D. Hissel; R. Mkahl

2011-01-01

236

PseAAC-Builder: a cross-platform stand-alone program for generating various special Chou's pseudo-amino acid compositions.  

PubMed

The pseudo-amino acid composition has been widely used to convert complicated protein sequences with various lengths to fixed length digital feature vectors while keeping considerable sequence order information. However, so far the only software available to the public is the web server PseAAC (http://www.csbio.sjtu.edu.cn/bioinf/PseAAC), which has some limitations in dealing with large-scale datasets. Here, we propose a new cross-platform stand-alone software program, called PseAAC-Builder (http://www.pseb.sf.net), which can be used to generate various modes of Chou's pseudo-amino acid composition in a much more efficient and flexible way. It is anticipated that PseAAC-Builder may become a useful tool for studying various protein attributes. PMID:22459120

Du, Pufeng; Wang, Xin; Xu, Chao; Gao, Yang

2012-06-15

237

Management of in-stent restenosis in peripheral arteries: are DEBs sufficient as stand-alone treatment for femoro-popliteal in-stent restenosis?  

PubMed

The treatment of in-stent restenosis (ISR) in the femoro-popliteal artery (FPA) is one of the major challenges of endovascular therapy, occurring in up to 40% of femoro-popliteal lesions treated with bare-metal stents within 1 year of treatment. Drug-eluting technologies, involving local delivery of paclitaxel, are providing a new paradigm for the treatment of ISR. Preliminary experience shows promising results compared to other techniques such as cutting balloon angioplasty and debulking strategies. Based on available data, drug-eluting balloons (DEBs) seem sufficient as stand-alone treatment of FPA-ISR. However, larger evidence from randomized studies is warranted to identify the clinical and/or anatomical setting in which they could fail. PMID:24755701

Franzone, A; Stabile, E; Carbone, A; Scudiero, F; Trimarco, B; Esposito, G

2014-06-01

238

Description of photovoltaic village power systems in the United States and Africa  

NASA Technical Reports Server (NTRS)

The paper describes the designs, hardware, and installations of NASA photovoltaic power systems in the village of Schuchuli in Arizona and Tangaye in Upper Volta, Africa. The projects were designed to demonstrate that current photovoltaic system technology can provide electrical power for domestic services for small, remote communities. The Schuchuli system has a 3.5 kW peak solar array which provides power for water pumping, a refrigerator for each family, lights, and community washing and sewing machines. The 1.8 kW Tangaye system provides power for pumping, flour milling, and lights in the milling building. Both are stand-alone systems operated by local personnel, and they are monitored by NASA to measure design adequacy and refine future designs.

Ratajczak, A. F.; Bifano, W. J.

1979-01-01

239

Mid-term Clinical Outcomes of Stand-alone Posterior Interbody Fusion with Rectangular Cages: A 4-year-minimum Follow-up  

PubMed Central

Objective We sought to determine minimum 4 years of clinical outcomes including fusion rate, revision rate and complications of patients who underwent placement of rectangular stand-alone cages. Methods Thirty-three cases of degenerative spine that had been followed for at least 4-years were reviewed retrospectively. Cages were inserted at L4-L5 level or L5-S1 in 27 or in 6 cases respectively. Visual analogue scale (VAS), Odom's criteria, fusion rate, intervertebral disc height and lumbar lordosis were determined pre- and post-operatively on standing x-rays. Amount of intra- and postoperative blood loss, total volume transfused, duration of surgery and perioperative complications were also evaluated. Results The mean VAS score of back pain and sciatica were improved from 8.0 and 7.0 points to 3.4 and 2.4 during 1 years follow-up visit and the scores was raised gradually. Also, during the follow-up, 94% of patients showed excellent or good outcomes by the Odom's criteria. Intervertebral disc height was increased from 8.2±1.4mm to 9.2±1.9mm at the first year of follow-up, however, found to be decreased and stabilized to 8.3±1.8mm after 2 years. The fusion rate was approximately 91% after 4 year postoperative. The segmental angle of lordosis was increased significantly by two years but it was not maintained after four years. A statistically insignificant change in total lumbar lordosis was also observed. Three patients (9%) had experienced perioperative complications. Conclusion The use of rectangular stand-alone cages for posterior lumbar interbody fusion (PLIF) resulted in a various degree of subsidence and demonstrate very low complication rate, high functional stability and improved clinical outcomes in patients with degenerative lumbar disc disease.

Cho, Kyung Rae; Lee, Sun-Ho; Kim, Eun Sang

2013-01-01

240

Power system  

DOEpatents

A power system includes a prime mover, a transmission, and a fluid coupler having a selectively engageable lockup clutch. The fluid coupler may be drivingly connected between the prime mover and the transmission. Additionally, the power system may include a motor/generator drivingly connected to at least one of the prime mover and the transmission. The power-system may also include power-system controls configured to execute a control method. The control method may include selecting one of a plurality of modes of operation of the power system. Additionally, the control method may include controlling the operating state of the lockup clutch dependent upon the mode of operation selected. The control method may also include controlling the operating state of the motor/generator dependent upon the mode of operation selected.

Hickam, Christopher Dale (Glasford, IL)

2008-03-18

241

Relational-to-Object-Oriented Cross-Model Accessing Capability in a Multi-Model and Multi-Lingual Database System.  

National Technical Information Service (NTIS)

Conventional database management systems (DBMS) are stand-alone, each supporting a single data model and corresponding data language (ML). One organization might operate several stand-alone DBMS independently, each of which requires the knowledge of a dif...

R. K. Johnston

1993-01-01

242

Contextual regularity and complexity of neuronal activity: From stand-alone cultures to task-performing animals  

Microsoft Academic Search

Precursors of the superior information processing capabilities of our cortex can most probably be traced back to simple invertebrate systems. Using a unique set of newly developed neuronal preparations and state-of-the-art analysis tools, we show that insect neurons have the ability to self-regulate the information capacity of their electrical activity. We characterize the activity of a distinct population of neurons

Amir Ayali; E. Fuchs; Y. Zilberstein; A. Robinson; Orit Shefi; Eyal Hulata; Itay Baruchi; Eshel Ben-jacob

2004-01-01

243

Three-Dimensional Virtual Model of the Human Temporal Bone: A Stand-Alone, Downloadable Teaching Tool  

PubMed Central

Objective To develop a three-dimensional virtual model of a human temporal bone based on serial histologic sections. Background The three-dimensional anatomy of the human temporal bone is complex, and learning it is a challenge for students in basic science and in clinical medicine. Methods Every fifth histologic section from a 14-year-old male was digitized and imported into a general purpose three-dimensional rendering and analysis software package called Amira (version 3.1). The sections were aligned, and anatomic structures of interest were segmented. Results The three-dimensional model is a surface rendering of these structures of interest, which currently includes the bone and air spaces of the temporal bone; the perilymph and endolymph spaces; the sensory epithelia of the cochlear and vestibular labyrinths; the ossicles and tympanic membrane; the middle ear muscles; the carotid artery; and the cochlear, vestibular, and facial nerves. For each structure, the surface transparency can be individually controlled, thereby revealing the three-dimensional relations between surface landmarks and underlying structures. The three-dimensional surface model can also be “sliced open” at any section and the appropriate raw histologic image superimposed on the cleavage plane. The image stack can also be resectioned in any arbitrary plane. Conclusion This model is a powerful teaching tool for learning the complex anatomy of the human temporal bone and for relating the two-dimensional morphology seen in a histologic section to the three-dimensional anatomy. The model can be downloaded from the Eaton-Peabody Laboratory web site, packaged within a cross-platform freeware three-dimensional viewer, which allows full rotation and transparency control.

Wang, Haobing; Northrop, Clarinda; Burgess, Barbara; Liberman, M. Charles; Merchant, Saumil N.

2007-01-01

244

Assessment of H 2- and H 2O-based renewable energy-buffering systems in minor islands  

Microsoft Academic Search

The paper assesses the energy and environmental performance of two solutions designed to complement renewable energy (RE) technologies, in stand-alone power system (SAPS) configuration typical of minor Mediterranean islands, by converting the available RE surplus. The studied SAPS, based on the Ventotene island demographic, meteorological and load data, features high renewable energy penetration onto the load power demand, i.e. up

Alessandro Corsini; Franco Rispoli; Mario Gamberale; Eileen Tortora

2009-01-01

245

Transportable 5 MW power supply system for gyrotron operation  

NASA Astrophysics Data System (ADS)

A transportable power supply system was designed to operate gyrotrons at varying locations. The system is designed to operate with an output of -100 kV at 50 A during CW operation (5 MW). The system employs various components previously used on other fusion-related experiments and some newly constructed components. The existing components that were modified for the higher power operation, as well as for transportability, are the raw dc power supply and the modulator/regulator. A newly designed capacitor bank, with a crowbar, was installed as an intermediate element between the power supply and the modulator/regulator, using existing capacitors. When the time comes for the system to be moved to a new location, the system breaks down into six large pieces that can be reassembled in a week. The entire system is controlled by a computer automated measurement and control (CAMAC)-based computer control system that can easily be tied into the rest of the gyrotron subsystems or can be used as a stand-alone system running the power supply system itself.

Jackson, M. C.; Garner, D. R.; Ravenscroft, D. S.; Weiss, W. C.

1991-09-01

246

Low-frequency switching voltage regulators for terrestrial photovoltaic systems  

NASA Technical Reports Server (NTRS)

The photovoltaic technology project and the stand alone applications project are discussed. Two types of low frequency switching type regulators were investigated. The design, operating characteristics and field application of these regulators is described. The regulators are small in size, low in cost, very low in power dissipation, reliable and allow considerable flexibility in system design.

Delombard, R.

1984-01-01

247

Wind-Powered Water Desalination Plant for a Small Island Community at the German Coast of the North Sea - Design and Working Experience.  

National Technical Information Service (NTIS)

A wind powered water desalination plant is operated as a 'remote stand alone system' for the fresh water supply of the small island of Suederoog at the German coast of the North Sea. The project is carried out jointly by MAN Neue Technologie Muenchen and ...

G. Petersen S. Fries K. Kaiba D. Knuenz

1983-01-01

248

Graphical contig analyzer for all sequencing platforms (G4ALL): a new stand-alone tool for finishing and draft generation of bacterial genomes  

PubMed Central

Genome assembly has always been complicated due to the inherent difficulties of sequencing technologies, as well the computational methods used to process sequences. Although many of the problems for the generation of contigs from reads are well known, especially those involving short reads, the orientation and ordination of contigs in the finishing stages is still very challenging and time consuming, as it requires the manual curation of the contigs to guarantee correct identification them and prevent misassembly. Due to the large numbers of sequences that are produced, especially from the reads produced by next generation sequencers, this process demands considerable manual effort, and there are few software options available to facilitate the process. To address this problem, we have developed the Graphic Contig Analyzer for All Sequencing Platforms (G4ALL): a stand-alone multi-user tool that facilitates the editing of the contigs produced in the assembly process. Besides providing information on the gene products contained in each contig, obtained through a search of the available biological databases, G4ALL produces a scaffold of the genome, based on the overlap of the contigs after curation. Availability The software is available at: http://www.genoma.ufpa.br/rramos/softwares/g4all.xhtml

Ramos, Rommel Thiago Juca; Carneiro, Adriana R; Caracciolo, Pablo H; Azevedo, Vasco; Schneider, Maria Paula C; Barh, Debmalya; Silva, Artur

2013-01-01

249

Alternative energy facilities based on site matching and generation unit sizing for remote area power supply  

Microsoft Academic Search

This paper presents the decision support technique and influencing factors in the design of an integrated solar-wind power system for stand-alone applications. Results of investigations on application of alternative energy facility like wind, photovoltaic (PV), and Integration of wind–PV power generating systems for Remote Area Power Supply have been presented. A weather model-based site matching of equipment and a simple

Pradeep K. Katti; Mohan K. Khedkar

2007-01-01

250

Optimum photovoltaic array size for a hybrid wind\\/PV system  

Microsoft Academic Search

A methodology for calculation of the optimum size of a PV array for a stand-alone hybrid wind\\/PV power system is developed. Long term data of wind speed and irradiance recorded for every hour of the day for 30 years were used. These data were used to calculate the probability density functions of the wind speed and the irradiance for each

Bogdan S. Borowy; Ziyad M. Salameh

1994-01-01

251

Design description of the Tangaye Village photovoltaic power system  

NASA Technical Reports Server (NTRS)

The engineering design of a stand alone photovoltaic (PV) powered grain mill and water pump for the village of Tangaye, Upper Volta is described. The socioeconomic effects of reducing the time required by women in rural areas for drawing water and grinding grain were studied. The suitability of photovoltaic technology for use in rural areas by people of limited technical training was demonstrated. The PV system consists of a 1.8-kW (peak) solar cell array, 540 ampere hours of battery storage, instrumentation, automatic controls, and a data collection and storage system. The PV system is situated near an improved village well and supplies d.c. power to a grain mill and a water pump. The array is located in a fenced area and the mill, battery, instruments, controls, and data system are in a mill building. A water storage tank is located near the well. The system employs automatic controls which provide battery charge regulation and system over and under voltage protection. This report includes descriptions of the engineering design of the system and of the load that it serves; a discussion of PV array and battery sizing methodology; descriptions of the mechanical and electrical designs including the array, battery, controls, and instrumentation; and a discussion of the safety features. The system became operational on March 1, 1979.

Martz, J. E.; Ratajczak, A. F.

1982-01-01

252

NEW APPROACH IN THERMAL MONITORING OF LARGE POWER TRANSFORMERS APPLIED ON A 350 MVA ODAF-COOLED UNIT  

Microsoft Academic Search

Large power transformers belong to the most valuable and important assets in electrical power systems. The ageing of the used oil\\/paper-insulation primarily depends on the hot-spot temperature of the solid insulation system. Hence it is the dominant factor limiting the lifetime of the transformer. Therefore in 1996 a prototype of a stand alone thermal monitoring system was developed and installed

Enzo CARDILLO; Kurt FESER

253

Market assessment of photovoltaic power systems for agricultural applications in the Philippines  

NASA Technical Reports Server (NTRS)

The market potential in the Philippines for stand alone photovoltaic (P/V) systems in agriculture was assessed. Applications include: irrigation, postharvest operation, food and fiber processing and storage, and livestock and fisheries operations. Power and energy use profiles for many applications as well as assessments of business, government and financial climate for P/V sales are described. Many characteristics of the Philippine agriculture and energy sector favorably influence the use of P/V systems. However, serious and significant barriers prevent achieving the technically feasible, cost competitive market for P/V systems in the agricultural sector. The reason for the small market is the limited availability capital for financing P/V systems. It is suggested that innovative financing schemes and promotional campaigns should be devised.

Cabraal, R. A.; Delasanta, D.; Burrill, G.

1981-01-01

254

Market assessment of photovoltaic power systems for agricultural applications worldwide  

NASA Technical Reports Server (NTRS)

Agricultural sector PV market assessments conducted in the Phillippines, Nigeria, Mexico, Morocco, and Colombia are extrapolated worldwide. The types of applications evaluated are those requiring less than 15 kW of power and operate in a stand alone mode. The major conclusions were as follows: PV will be competitive in applications requiring 2 to 3 kW of power prior to 1983; by 1986 PV system competitiveness will extend to applications requiring 4 to 6 kW of power, due to capital constraints, the private sector market may be restricted to applications requiring less than about 2 kW of power; the ultimate purchase of larger systems will be governments, either through direct purchase or loans from development banks. Though fragmented, a significant agriculture sector market for PV exists; however, the market for PV in telecommunications, signalling, rural services, and TV will be larger. Major market related factors influencing the potential for U.S. PV Sales are: lack of awareness; high first costs; shortage of long term capital; competition from German, French and Japanese companies who have government support; and low fuel prices in capital surplus countries. Strategies that may aid in overcoming some of these problems are: setting up of a trade association aimed at overcoming problems due to lack of awareness, innovative financing schemes such as lease arrangements, and designing products to match current user needs as opposed to attempting to change consumer behavior.

Cabraal, A.; Delasanta, D.; Rosen, J.; Nolfi, J.; Ulmer, R.

1981-01-01

255

Control of doubly-fed induction generator system using PFNN  

Microsoft Academic Search

An intelligent controlled doubly-fed induction generator (DFIG) system using probabilistic fuzzy neural network (PFNN) is proposed in this study. This system can be applied as a stand-alone power supply system or as the emergency power system when the electricity grid fails for all sub-synchronous, synchronous and super-synchronous conditions. The rotor side converter is controlled using the field-oriented control to produce

Faa-Jeng Lin; Kuang-Hsiung Tan; Zong-Han Lu; Yung-Ruei Chang

2011-01-01

256

Evaluation of a photovoltaic energy mechatronics system with a built-in quadratic maximum power point tracking algorithm  

SciTech Connect

The historically high cost of crude oil price is stimulating research into solar (green) energy as an alternative energy source. In general, applications with large solar energy output require a maximum power point tracking (MPPT) algorithm to optimize the power generated by the photovoltaic effect. This work aims to provide a stand-alone solution for solar energy applications by integrating a DC/DC buck converter to a newly developed quadratic MPPT algorithm along with its appropriate software and hardware. The quadratic MPPT method utilizes three previously used duty cycles with their corresponding power outputs. It approaches the maximum value by using a second order polynomial formula, which converges faster than the existing MPPT algorithm. The hardware implementation takes advantage of the real-time controller system from National Instruments, USA. Experimental results have shown that the proposed solar mechatronics system can correctly and effectively track the maximum power point without any difficulties. (author)

Chao, R.M.; Ko, S.H.; Lin, I.H. [Department of Systems and Naval Mechatronics Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Pai, F.S. [Department of Electronic Engineering, National University of Tainan (China); Chang, C.C. [Department of Environment and Energy, National University of Tainan (China)

2009-12-15

257

Long-term field test of solar PV power generation using one-axis 3-position sun tracker  

Microsoft Academic Search

The 1 axis-3 position (1A-3P) sun tracking PV was built and tested to measure the daily and long-term power generation of the solar PV system. A comparative test using a fixed PV and a 1A-3P tracking PV was carried out with two identical stand-alone solar-powered LED lighting systems. The field test in the particular days shows that the 1A-3P tracking

B. J. Huang; W. L. Ding; Y. C. Huang

2011-01-01

258

An Efficient Wind–Photovoltaic Hybrid Generation System Using Doubly Excited Permanent-Magnet Brushless Machine  

Microsoft Academic Search

With ever-increasing concerns on energy issues, the development of renewable energy sources is becoming more and more attractive. This paper first reviews both the wind power and photovoltaic (PV) power generation techniques and their maximum-power-point tracking (MPPT) methods. Then, a new stand-alone wind-PV hybrid generation system is proposed for application to remote and isolated areas. For the wind power generation

Chunhua Liu; K. T. Chau; Xiaodong Zhang

2010-01-01

259

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

Microsoft Academic Search

This paper deals with an experimental outdoor annual performance evaluation of 2.32kWP photovoltaic (PV) power system located at solar energy park in New Delhi composite climatic conditions. This PV system operates the daily electrical load nearly 10kWh\\/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

Arvind Chel; G. N. Tiwari

2010-01-01

260

Fuzzy dynamic modeling and predictive load following control of a solid oxide fuel cell power system  

Microsoft Academic Search

Solid oxide fuel cell (SOFC) is widely accepted for clean and distributed power generation use, but critical operation problems often occur when stand-alone fuel cell is directly connected to the electricity grid or the DC electric user. In order to address these problems, in this paper a data-driven fuzzy identification method is applied to the dynamic modeling of an integrated

Tiejun Zhang; Gang Feng; Wenguo Xiang

2008-01-01

261

Rapid Load Following of an SOFC Power System via Stable Fuzzy Predictive Tracking Controller  

Microsoft Academic Search

The solid oxide fuel cell (SOFC) is widely accepted for clean and distributed power generation use, but critical operation problems often occur when the stand-alone fuel cell is directly connected to the electricity grid or the dc electric user. In order to address these problems, in this paper, a data-driven fuzzy modeling method is employed to identify the dynamic model

Tiejun Zhang; Gang Feng

2009-01-01

262

Phase 1 of the First Solar Small Power System Experiment (experimental System No. 1). Volume 1: Technical Studies for Solar Point-focusing, Distributed Collector System, with Energy Conversion at the Collector, Category C  

NASA Technical Reports Server (NTRS)

The technical and economic feasibility of a solar electric power plant for a small community is evaluated and specific system designs for development and demonstration are selected. All systems investigated are defined as point focusing, distributed receiver concepts, with energy conversion at the collector. The preferred system is comprised of multiple parabolic dish concentrators employing Stirling cycle engines for power conversion. The engine, AC generator, cavity receiver, and integral sodium pool boiler/heat transport system are combined in a single package and mounted at the focus of each concentrator. The output of each concentrator is collected by a conventional electrical distribution system which permits grid-connected or stand-alone operation, depending on the storage system selected.

Clark, T. B. (editor)

1979-01-01

263

Phase 1 of the first solar small power system experiment (experimental system no. 1). Volume 1: Technical studies for solar point-focusing, distributed collector system, with energy conversion at the collector, category C  

NASA Technical Reports Server (NTRS)

The technical and economic feasibility of a solar electric power plant for a small community is evaluated and specific system designs for development and demonstration are selected. All systems investigated are defined as point focusing, distributed receiver concepts, with energy conversion at the collector. The preferred system is comprised of multiple parabolic dish concentrators employing Stirling cycle engines for power conversion. The engine, AC generator, cavity receiver, and integral sodium pool boiler/heat transport system are combined in a single package and mounted at the focus of each concentrator. The output of each concentrator is collected by a conventional electrical distribution system which permits grid-connected or stand-alone operation, depending on the storage system selected.

Clark, T. B. (editor)

1979-01-01

264

Description of photovoltaic village power systems in the United States and Africa  

NASA Technical Reports Server (NTRS)

Photovoltaic power systems in remote villages in the United States and Africa are described. These projects were undertaken to demonstrate that existing photovoltaic system technology is capable of providing electrical power for basic domestic services for the millions of small, remote communities in both developed and developing countries. One system is located in the Papago Indian Village of Schuchuli in southwest Arizona (U. S.) and became operational 16 December 1978. The other system is located in Tangaye, a rural village in Upper Volta, Africa. It became operational 1 March 1979. The Schuchuli system has a 3.5 kW (peak) solar array which provides electric power for village water pumping, a refrigerator for each family, lights in the village buildings, and a community washing machine and sewing machine. The 1.8 kW (peak) Tangaye system provides power for community water pumping, flour milling and lights in the milling building. These are both stand-alone systems (i.e., no back-up power source) which are being operated and maintained by local personnel. Both systems are instrumented. Systems operations are being monitored by NASA to measure design adequacy and to refine designs for future systems.

Ratajczak, A. F.; Bifano, W. J.

1979-01-01

265

Cost–benefit analysis of remote hybrid wind–diesel power stations: Case study Aegean Sea islands  

Microsoft Academic Search

More than one third of world population has no direct access to interconnected electrical networks. Hence, the electrification solution usually considered is based on expensive, though often unreliable, stand-alone systems, mainly small diesel-electric generators. Hybrid wind–diesel power systems are among the most interesting and environmental friendly technological alternatives for the electrification of remote consumers, presenting also increased reliability. More precisely,

J. K. Kaldellis; K. A. Kavadias

2007-01-01

266

Stand-alone groundwater desalination system using reverse osmosis combined with a cooled greenhouse for use in arid and semi-arid zones of India  

Microsoft Academic Search

In many areas of northern India, salinity renders groundwater unsuitable for drinking and even for irrigation. Though membrane treatment can be used to remove the salt, there are some drawbacks to this approach e.g. (1) depletion of the groundwater due to over-abstraction, (2) saline contamination of surface water and soil caused by concentrate disposal and (3) high electricity usage. To

P. A. Davies; A. K. Hossain; P. Vasudevan

2009-01-01

267

Transients in Power Systems  

Microsoft Academic Search

Power system engineering largely focuses on steady state analysis. The main areas of power system engineering are power flow studies and fault studies - both steady state technologies. But the world is largely transient, and power systems are always subject to time varying and short lived signals. This technical report concerns several important topics in transient analyses of power systems.

M. Belkhayat; J. Edwards; N. Hoonchareon; O. Marte; D. Stenberg; E. Walters

1995-01-01

268

Power management system  

DOEpatents

A method of managing power resources for an electrical system of a vehicle may include identifying enabled power sources from among a plurality of power sources in electrical communication with the electrical system and calculating a threshold power value for the enabled power sources. A total power load placed on the electrical system by one or more power consumers may be measured. If the total power load exceeds the threshold power value, then a determination may be made as to whether one or more additional power sources is available from among the plurality of power sources. At least one of the one or more additional power sources may be enabled, if available.

Algrain, Marcelo C. (Peoria, IL); Johnson, Kris W. (Washington, IL); Akasam, Sivaprasad (Peoria, IL); Hoff, Brian D. (East Peoria, IL)

2007-10-02

269

Small sodium sulfur battery for solar and wind energy systems  

NASA Astrophysics Data System (ADS)

A conceptual design of a 1 MWh sodium-sulfur storage battery is given. The battery is to be used in small (15 kW), stand-alone solar or wind electrical power systems. The design uses approximately 1,400 sodium-sulfur cells of a new, high energy capacity configuration. The cells are connected in a parallel/series network to give a discharge voltage of 120 VDC minimum, and with sufficient cell redundancy for a 10 year battery life. A description is given of the battery structure, thermal enclosure, and controls. Battery performance estimates are given, including the effect of thermal losses. It is concluded that sodium-sulfur batteries hold promise for good performance and reliability in small, stand-alone power systems.

Haskins, H. J.; Domaszewicz, A. G.

270

Satellite power systems technology  

Microsoft Academic Search

The development emphasis of the next decade in electrical power systems for satellites will be to provide larger amounts of electrical power with dramatically improved power system performance. Reliability, survivability, adaptability, scalability and endurability will continue to be important power system technology considerations for most missions. This paper addresses increasing power trends seen for future satellite missions, describes the current

R. R. Barthelemy; L. D. Massie

1984-01-01

271

Development of a Multi-Bus, Multi-Source Reconfigurable Stirling Radioisotope Power System Test Bed  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) has typically used Radioisotope Thermoelectric Generators (RTG) as their source of electric power for deep space missions. A more efficient and potentially more cost effective alternative to the RTG, the high efficiency 110 watt Stirling Radioisotope Generator 110 (SRG110) is being developed by the Department of Energy (DOE), Lockheed Martin (LM), Stirling Technology Company (STC) and NASA Glenn Research Center (GRC). The SRG110 consists of two Stirling convertors (Stirling Engine and Linear Alternator) in a dual-opposed configuration, and two General Purpose Heat Source (GPHS) modules. Although Stirling convertors have been successfully operated as a power source for the utility grid and as a stand-alone portable generator, demonstration of the technology required to interconnect two Stirling convertors for a spacecraft power system has not been attempted. NASA GRC is developing a Power System Test Bed (PSTB) to evaluate the performance of a Stirling convertor in an integrated electrical power system application. This paper will describe the status of the PSTB and on-going activities pertaining to the PSTB in the NASA Thermal-Energy Conversion Branch of the Power and On-Board Propulsion Technology Division.

Coleman, Anthony S.

2004-01-01

272

Modeling, analysis and control of fuel cell hybrid power systems  

NASA Astrophysics Data System (ADS)

Transient performance is a key characteristic of fuel cells, that is sometimes more critical than efficiency, due to the importance of accepting unpredictable electric loads. To fulfill the transient requirement in vehicle propulsion and portable fuel cell applications, a fuel cell stack is typically coupled with a battery through a DC/DC converter to form a hybrid power system. Although many power management strategies already exist, they all rely on low level controllers that realize the power split. In this dissertation we design controllers that realize various power split strategies by directly manipulating physical actuators (low level commands). We maintain the causality of the electric dynamics (voltage and current) and investigate how the electric architecture affects the hybridization level and the power management. We first establish the performance limitations associated with a stand-alone and power-autonomous fuel cell system that is not supplemented by an additional energy storage and powers all its auxiliary components by itself. Specifically, we examine the transient performance in fuel cell power delivery as it is limited by the air supplied by a compressor driven by the fuel cell itself. The performance limitations arise from the intrinsic coupling in the fluid and electrical domain between the compressor and the fuel cell stack. Feedforward and feedback control strategies are used to demonstrate these limitations analytically and with simulations. Experimental tests on a small commercial fuel cell auxiliary power unit (APU) confirm the dynamics and the identified limitations. The dynamics associated with the integration of a fuel cell system and a DC/DC converter is then investigated. Decentralized and fully centralized (using linear quadratic techniques) controllers are designed to regulate the power system voltage and to prevent fuel cell oxygen starvation. Regulating these two performance variables is a difficult task and requires a compromise due to the conflicting objectives. The compromise can be mitigated by augmenting the fuel cell power system with an energy buffer such as a battery. We consider two different and popular ways of connecting the battery and the fuel cell to the load and we refer to them as electric architectures. Various controller gains are used to span the fuel cell operation from load-following to load-leveling, and hence, to determine adequate fuel cell-battery sizing (hybridization level) and the associated trends in the system efficiency.

Suh, Kyung Won

273

Small sodium sulfur battery for solar and wind energy systems  

Microsoft Academic Search

A conceptual design of a 1 MWh sodium-sulfur storage battery is given. The battery is to be used in small (15 kW), stand-alone solar or wind electrical power systems. The design uses approximately 1,400 sodium-sulfur cells of a new, high energy capacity configuration. The cells are connected in a parallel\\/series network to give a discharge voltage of 120 VDC minimum,

H. J. Haskins; A. G. Domaszewicz

1981-01-01

274

Renewable hybrid system with battery storage for safe loads supply  

Microsoft Academic Search

This paper presents a renewable hybrid system with battery storage which can work as a stand-alone and\\/or grid- connected mode. It consists in a wind turbine with permanent magnet synchronous generator (PMSG) and a photovoltaic panel forming a single-phase micro-grid. The wind generator and photovoltaic module are connected to the micro-grid via single- phase converters. Maximum power point tracker (MPPT)

L. Barote; C. Marinescu

2011-01-01

275

A Modular Plasma System Combining Ion Thrusters, Inertial Electrostatic Confinement, and Theta Pinch Devices  

Microsoft Academic Search

This system is designed to improve the effectiveness and investigate the synergy between several types of ion thrusters and fusion devices, which have typically been used as stand-alone systems. The experimental apparatus is powered by a 45kV capacitor bank, which can be discharged simultaneously through 2 separate cylindrical copper theta pinch coils. In addition 60kV can be applied to the

Jeffrey E. Norman; David N. Ruzic

1999-01-01

276

Development of Standardized Power Electronic Components, Subsystems, and Systems for Increased Modularity and Scalability  

SciTech Connect

Power electronics devices hold substantial promise for making distributed energy applications more efficient and cost effective. This project is motivated towards developing and testing inverters that will allow distributed energy systems to provide ancillary services such as voltage and VAR regulation, and increased grid reliability by seamlessly transitioning between grid-tied and stand-alone operation modes. The objectives of this project are to identify system integration and optimization issues and technologies and to provide solutions through research, analysis, and testing of power electronic interfaces for distributed energy applications that are cost-competitive and have substantially faster response times than conventional technologies. In addition, the testing of power electronics interfaces will develop a technical basis for performance assessment for distributed energy systems, subsystems, and components that will finally create a foundation for standardized measurements and test procedures. The ultimate goal for this research is to advance the potential benefits of distributed energy to provide ancillary services, enhance power system reliability, and allow customer choice.

Chakraborty, S.; Pink, C.; Price, J.; Kroposki, B.; Kern, G.

2007-11-01

277

Naval shipboard power system  

Microsoft Academic Search

Different naval shipboard power system architectures and their basic characteristics have been discussed in the paper. In addition the paper discusses about incorporation of platform management systems into the ship automation system that would enable monitoring and control of the shipboard power system, assessing and diagnosing system failures\\/damages and reconfiguring and restoring power to service loads with reduced manpower and

R. Jayabalan; B. Fahimi

2005-01-01

278

DSN Monitor and Control System, Mark III-80  

NASA Technical Reports Server (NTRS)

The Deep Space Network monitor and control system, Mark III-80 is described. The major implementations required to evolve from the Mark III-78 to the Mark III-80 configuration are identified. The affected facilities are the deep space stations and the network operations control center (NOCC). At the deep space stations a stand-alone host processor is implemented. Included are software (host software) changes which provide downline loading to the stand-alone host processor from a disc unit of any idle data system computer. At deep space stations with a 34 m antenna, the microwave subsystem is provided with an interface which allows remote configuration selection at the central monitor and control operator's position. In the NOCC, software changes are implemented to provide precision power monitor and GCF monitor displays.

Leflang, J. G.

1980-01-01

279

MODULAR BAYESIAN INFERENCE AND LEARNING OF DECISION NETWORKS AS STAND-ALONE MECHANISMS OF THE MABEL MODEL: IMPLICATIONS FOR VISUALIZATION, COMPREHENSION, AND POLICY MAKING  

Microsoft Academic Search

This paper describes a modular component of the MABEL model agents' cognitive inference mechanism. The probabilistic and probabilogic representation of the agents' environment and state space is coupled with a Bayesian belief and decision network functionality, which in fact holds Markovian semiparametric properties. Different approaches to modeling multi-agent systems are described and analyzed; problem-, model-, and knowledge-driven approaches to agent

K. ALEXANDRIDIS; B. PIJANOWSKI

280

DESIGNING SYSTEMS FOR THE CREATION AND EVALUATION OF DYNAMIC PERIPHERAL SOUNDSCAPES: A USABILITY STUDY  

Microsoft Academic Search

Sonifications have proven useful as stand-alone displays and in bimodal audio-visual displays. Audio is powerful in a peripheral display due to its unobtrusive and omni- directional nature. This study examined the creation and usability of peripheral auditory displays or 'soundscapes' composed of ecological sounds. A system was created for dynamically generating soundscapes from a data source according to a threshold-based

Bradley S. Mauney; Bruce N. Walker

2004-01-01

281

Brackish water desalination by a hybrid forward osmosis–nanofiltration system using divalent draw solute  

Microsoft Academic Search

In the last decade osmotically driven membrane processes have attracted growing interest in wastewater treatment, desalination and power generation. A hybrid forward osmosis–nanofiltration (FO–NF) system designed for brackish water desalination was systematically investigated in this study. The hybrid FO–NF process was also compared with a stand-alone reverse osmosis (RO) process in brackish water desalination. It is found that the hybrid

Shuaifei Zhao; Linda Zou; Dennis Mulcahy

282

Performance characteristics of solar-photovoltaic flywheel-storage systems  

NASA Astrophysics Data System (ADS)

A solar photovoltaic energy flywheel storage and conversion system for residential applications was tested. Performance and efficiency measurements were conducted on the system, which utilizes low loss magnetic bearings, maximum power point tracking of the photovoltaic array, integrated permanent magnet motor generator, and output power conditioning sections of either the stand alone cycloconverter or utility interactive inverter type. The overall in/out electrical storage efficiency of the flywheel system was measured along with the power transfer efficiencies of the individual components and the system spin down tare losses. The system compares favorably with systems which use batteries and inverters.

Jarvinen, P. O.; Brench, B. L.; Rasmussen, N. E.

283

Satellite power system simulation  

Microsoft Academic Search

In order to furnish a useful tool for the power system preliminary sizing, a satellite power system simulator was developed. The simulator has a modular structure where each module implements the mathematical model of the system components (solar array, battery, voltage regulators etc.). The software allows both the verification of the rating co-ordination of all those parts composing the power

G. Colombo; U. Grasselli; A. De Luca; A. Spizzichino; S. Falzini

1997-01-01

284

Reliability considerations in the design of solar photovoltaic power systems  

NASA Astrophysics Data System (ADS)

A systems level approach to reliability analyses for solar photovoltaic systems is presented, and it is shown how these analyses can be useful in photovoltaic systems design even though detailed reliability data are not yet available. Traditional reliability techniques and trade-offs are discussed, and relationships between reliability, maintainability, and availability are reviewed employing minimum life cycle cost as the parameter to be optimized. A list of available techniques that are useful today is presented, as is a list providing a series of techniques that will be useful when more field and test reliability data on photovoltaic systems are available. Three typical solar photovoltaic systems are shown in block diagrams and discussed. They are (1) a stand-alone photovoltaic system, (2) a stand-alone system with battery energy storage, and (3) a system with a utility back-up. Each system is analyzed to the subsystem level with the aid of two reliability analysis techniques: the failure modes and effects analyses and the fault tree approach.

Stember, L. H.

1981-05-01

285

Design, fabrication, and certification of advanced modular PV power systems. Final technical progress report  

SciTech Connect

Solar Electric Specialties Company (SES) has completed a two and a half year effort under the auspices of the US Department of Energy (DOE) PVMaT (Photovoltaic Manufacturing Technology) project. Under Phase 4A1 of the project for Product Driven System and Component Technology, the SES contract ``Design, Fabrication and Certification of Advanced Modular PV Power Systems`` had the goal to reduce installed system life cycle costs through development of certified (Underwriters Laboratories or other listing) and standardized prototype products for two of the product lines, MAPPS{trademark} (Modular Autonomous PV Power Supply) and Photogensets{trademark}. MAPPS are small DC systems consisting of Photovoltaic modules, batteries and a charge controller and producing up to about a thousand watt-hours per day. Photogensets are stand-alone AC systems incorporating a generator as backup for the PV in addition to a DC-AC inverter and battery charger. The program tasks for the two-year contract consisted of designing and fabricating prototypes of both a MAPPS and a Photogenset to meet agency listing requirements using modular concepts that would support development of families of products, submitting the prototypes for listing, and performing functionality testing at Sandia and NREL. Both prototypes were candidates for UL (Underwriters Laboratories) listing. The MAPPS was also a candidate for FM (Factory Mutual) approval for hazardous (incendiary gases) locations.

Lambarski, T.; Minyard, G. [Solar Electric Specialties Co., Willits, CA (United States)

1998-10-01

286

Chapter 2: Stand-alone Applications - TOPCAT  

NASA Astrophysics Data System (ADS)

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.

Miller, C. J.

287

Stand alone biofuel production from algae  

Microsoft Academic Search

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

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

2011-01-01

288

Cogeneration power systems  

NASA Technical Reports Server (NTRS)

Cogeneration is defined as the combination of electrical generation and process heat for more efficient use of fuel. Comparisons of energy utilization in conventional electric power plants and cogeneration electric power plants are presented. Characteristics of various cogeneration systems are also presented. Systems are analyzed for use in utility systems and industrial systems. Economic and cost analysis are reviewed.

Davis, H. S.

1978-01-01

289

Development of high power high brightness fiber coupled diode laser systems  

NASA Astrophysics Data System (ADS)

The improved wall-plug efficiency and minimal maintenance of diode laser systems over Nd:YAG and CO2 lasers has been admired by many manufacturers. Until recently, most diode laser systems could not compete at high-power levels or with the same beam quality. Nuvonyx reports the design and initial development of a diode laser system that delivers 2000 W from a 600 ?m core fiber with a 0.22 NA. This system is suitable as a stand-alone industrial direct diode laser system or as a multi-kilowatt fiber laser pump source. The development of a high brightness bar technology by Nuvonyx and its collaborators along with the use of polarization beam combining is the core of this laser system. Each emitter operates with a single lateral mode resulting in a high brightness bar that outputs up to 50 W. The wavelength of the laser is centered at 975 nm with a width of less than +/- 3 nm. The demonstration of this laser system defines a clear path to scale this technology to 4000 W.

Ostrom, Nels P.; Gall, Mike; Faircloth, Brian O.

2006-03-01

290

Effect of Initial Powder Morphology and Thermal and Mechanical Properties of Stand-Alone Plasma-Sprayed 7 wt%Y2O3-ZrO2 Coatings  

SciTech Connect

The effects of starting powder morphology on the thermal and mechanical properties of stand-alone plasma-sprayed 7 wt.% Y{sub 2}O{sub 3}-ZrO{sub 2}(YSZ) coatings were studied. Two powder morphologies were investigated: an agglomerated and sintered powder (referred to presently as 'AS') and a powder manufactured using plasma spheroidization to create hollow spheres (referred to presently as 'HS'). Coatings made from AS powders contained 0.21 wt.% SiO{sub 2} impurity, twice as much as observed in coatings made from HS powders. Properties of coatings made from each powder type were compared in the as-sprayed state and after 50 h heat treatments at temperatures ranging from 1000 to 1400 C. SEM microstructural investigations revealed significant differences in the porosity and distribution of pores in the coatings. In coatings made with AS powders the majority of the high aspect ratio pores were located between lamella (interlamellar porosity). In addition to interlamellar pores, coatings made with HS powders demonstrated 1.5 times more spherical-shaped globular pores by number located within lamella. Globular pores were shown to still exist in coatings made with HS powders after 50 h heat treatments at 1400 C. Archimedes porosity measurements showed that coatings made with AS powders typically contained 4-5% less total porosity than coatings made with HS powders. Thermal conductivity experiments using laser flash showed that there was no difference in the thermal conductivity of coatings made from either powder type in the as-sprayed state despite higher porosity in the coatings made from HS powders. After a 50 h heat treatment at 1000 and 1200 C, coatings made from both powder types still demonstrated statistically similar thermal conductivities. However, after a 50 h heat treatment at 1400 C the thermal conductivity of coatings made from AS powders was found to be 0.3 W/m/K higher than coatings made from HS powders. Microstructural differences in the coatings made from the two powder types that affected sintering rates, including the increased level of SiO{sub 2} impurities and fewer globular pores, were used to explain variations in properties. In uniaxial compression tests on stand-alone samples at 1000, 1100, and 1200 C, coatings made from AS powders typically relaxed more stress than coatings made from HS powders. Differences in coating relaxation became more apparent as the test temperature increased through 1200 C. The higher percentage of impurity SiO{sub 2} in the AS coatings is believed to contribute to increased relaxation via formation of a glassy phase at the grain boundaries which assists grain boundary sliding during elevated temperature deformation.

Ercan, Batur [ORNL; Bowman, Keith [ORNL; Trice, Rodney [ORNL; Wang, Hsin [ORNL; Porter, Wallace D [ORNL

2006-01-01

291

International Space Station Power Systems  

NASA Technical Reports Server (NTRS)

This viewgraph presentation gives a general overview of the International Space Station Power Systems. The topics include: 1) The Basics of Power; 2) Space Power Systems Design Constraints; 3) Solar Photovoltaic Power Systems; 4) Energy Storage for Space Power Systems; 5) Challenges of Operating Power Systems in Earth Orbit; 6) and International Space Station Electrical Power System.

Propp, Timothy William

2001-01-01

292

Economical space power systems  

NASA Astrophysics Data System (ADS)

A commercial approach to design and fabrication of an economical space power system is investigated. Cost projections are based on a 2 kW space power system conceptual design taking into consideration the capability for serviceability, constraints of operation in space, and commercial production engineering approaches. A breakdown of the system design, documentation, fabrication, and reliability and quality assurance estimated costs are detailed.

Burkholder, J. H.

1980-01-01

293

Power System Analysis  

NASA Astrophysics Data System (ADS)

Electric power generation that relies on various sources as the primary sources of energy is expected to bring down CO2 emissions levels to support the overall strategy to curb global warming. Accordingly, utilities are moving towards integrating more renewable sources for generation, mostly dispersed, and adopting Smart Grid Technologies for system control. In order to construct, operate, and maintain power systems stably and economically in such background, thorough understanding about the characteristics of power systems and their components is essential. This paper presents modeling and simulation techniques available for the analysis of critical aspects such as thermal capacity, stability, voltage stability, and frequency dynamics, vital for the stable operation of power systems.

Taniguchi, Haruhito

294

Space Nuclear Power Systems  

NASA Technical Reports Server (NTRS)

Fission power and propulsion systems can enable exciting space exploration missions. These include bases on the moon and Mars; and the exploration, development, and utilization of the solar system. In the near-term, fission surface power systems could provide abundant, constant, cost-effective power anywhere on the surface of the Moon or Mars, independent of available sunlight. Affordable access to Mars, the asteroid belt, or other destinations could be provided by nuclear thermal rockets. In the further term, high performance fission power supplies could enable both extremely high power levels on planetary surfaces and fission electric propulsion vehicles for rapid, efficient cargo and crew transfer. Advanced fission propulsion systems could eventually allow routine access to the entire solar system. Fission systems could also enable the utilization of resources within the solar system.

Houts, Michael G.

2012-01-01

295

Advanced electric power systems  

Microsoft Academic Search

An identification and preliminary evaluation was made of alternative advanced electric power systems which have been suggested for possible future use by the American electric utility industry. The motivation for interest in advanced power systems stems primarily from the rapidly rising costs of clean fossil fuels, especially conventional fuel oil, and uncertainties of fuel supply. Four basic energy sources have

Albert J. Giramonti; Robert D. Lessard

1975-01-01

296

Laboratory evaluation of a pilot cell battery protection system for photovoltaic applications  

NASA Technical Reports Server (NTRS)

An energy storage method for the 3.5 kW battery power system was investigated. The Pilot Cell Battery Protection System was tested for use in photovoltaic power systems and results show that this is a viable method of storage battery control. The method of limiting battery depth of discharge has the following advantages: (1) temperature sensitivity; (2) rate sensitivity; and (3) state of charge indication. The pilot cell concept is of interest in remote stand alone photovoltaic power systems. The battery can be protected from damaging overdischarge by using the proper ratio of pilot cell capacities to main battery capacity.

Cataldo, R. L.; Thomas, R. D.

1981-01-01

297

TROPIX power system architecture  

NASA Technical Reports Server (NTRS)

This document contains results obtained in the process of performing a power system definition study of the TROPIX power management and distribution system (PMAD). Requirements derived from the PMADs interaction with other spacecraft systems are discussed first. Since the design is dependent on the performance of the photovoltaics, there is a comprehensive discussion of the appropriate models for cells and arrays. A trade study of the array operating voltage and its effect on array bus mass is also presented. A system architecture is developed which makes use of a combination of high efficiency switching power convertors and analog regulators. Mass and volume estimates are presented for all subsystems.

Manner, David B.; Hickman, J. Mark

1995-01-01

298

Power systems and power plant control  

Microsoft Academic Search

This Proceedings consists of the 6 plenary papers and 65 of the contributed papers which were presented at the IFAC Symposium on Power Systems and Power Plant Control, held in Beijing, China on August 12-15, 1986. The control of power systems and of power plants is a subject of worldwide interest which continues to sustain a high level of research,

Pingyang

1987-01-01

299

Buyer's Guide to Computer Based Instructional Systems.  

ERIC Educational Resources Information Center

Examines the advantages and disadvantages of shared multiterminal computer based instruction (CBI) systems, dedicated multiterminal CBI systems, and stand-alone CBI systems. A series of questions guide consumers in matching a system's capabilities with an organization's needs. (MER)

Fratini, Robert C.

1981-01-01

300

Autonomous power expert system  

NASA Technical Reports Server (NTRS)

The goal of the Autonomous Power System (APS) program is to develop and apply intelligent problem solving and control technologies to the Space Station Freedom Electrical Power Systems (SSF/EPS). The objectives of the program are to establish artificial intelligence/expert system technology paths, to create knowledge based tools with advanced human-operator interfaces, and to integrate and interface knowledge-based and conventional control schemes. This program is being developed at the NASA-Lewis. The APS Brassboard represents a subset of a 20 KHz Space Station Power Management And Distribution (PMAD) testbed. A distributed control scheme is used to manage multiple levels of computers and switchgear. The brassboard is comprised of a set of intelligent switchgear used to effectively switch power from the sources to the loads. The Autonomous Power Expert System (APEX) portion of the APS program integrates a knowledge based fault diagnostic system, a power resource scheduler, and an interface to the APS Brassboard. The system includes knowledge bases for system diagnostics, fault detection and isolation, and recommended actions. The scheduler autonomously assigns start times to the attached loads based on temporal and power constraints. The scheduler is able to work in a near real time environment for both scheduling and dynamic replanning.

Ringer, Mark J.; Quinn, Todd M.

1990-01-01

301

Autonomous power expert system  

NASA Technical Reports Server (NTRS)

The goal of the Autonomous Power System (APS) program is to develop and apply intelligent problem solving and control technologies to the Space Station Freedom Electrical Power Systems (SSF/EPS). The objectives of the program are to establish artificial intelligence/expert system technology paths, to create knowledge based tools with advanced human-operator interfaces, and to integrate and interface knowledge-based and conventional control schemes. This program is being developed at the NASA-Lewis. The APS Brassboard represents a subset of a 20 KHz Space Station Power Management And Distribution (PMAD) testbed. A distributed control scheme is used to manage multiple levels of computers and switchgear. The brassboard is comprised of a set of intelligent switchgear used to effectively switch power from the sources to the loads. The Autonomous Power Expert System (APEX) portion of the APS program integrates a knowledge based fault diagnostic system, a power resource scheduler, and an interface to the APS Brassboard. The system includes knowledge bases for system diagnostics, fault detection and isolation, and recommended actions. The scheduler autonomously assigns start times to the attached loads based on temporal and power constraints. The scheduler is able to work in a near real time environment for both scheduling an dynamic replanning.

Ringer, Mark J.; Quinn, Todd M.

1990-01-01

302

Power Systems Control Architecture  

SciTech Connect

A diagram provided in the report depicts the complexity of the power systems control architecture used by the national power structure. It shows the structural hierarchy and the relationship of the each system to those other systems interconnected to it. Each of these levels provides a different focus for vulnerability testing and has its own weaknesses. In evaluating each level, of prime concern is what vulnerabilities exist that provide a path into the system, either to cause the system to malfunction or to take control of a field device. An additional vulnerability to consider is can the system be compromised in such a manner that the attacker can obtain critical information about the system and the portion of the national power structure that it controls.

James Davidson

2005-01-01

303

Two self-powered energy harvesting interfaces based on the optimized synchronous electric charge extraction technique  

NASA Astrophysics Data System (ADS)

Optimized synchronous electric charge extraction (OSECE) interface is a load weakly-dependant circuit, which is a favorable characteristic for piezoelectric wideband vibration energy harvesting. However, it introduces synchronous switches that need to be self-powered in a stand-alone system. This paper presents the design and experimental testing of two self-powered approaches for the OSECE technique. One is made of electronic switches driven by analog peak detector circuits; the other uses mechanical switches directly controlled by the ambient vibrations. Finally, advantages and drawbacks of the two approaches will be compared and discussed.

Wu, Yipeng; Badel, Adrien; Formosa, Fabien; Liu, Weiqun; Agbossou, Amen

2013-12-01

304

Dynamic power systems for power generation  

NASA Technical Reports Server (NTRS)

The characteristics of dynamic power systems have considerable potential value, especially for the space station. The base of technology that makes these dynamic power systems practical is reviewed. The following types of power-generating systems are examined herein: organic Rankine cycle, potassium Rankine cycle, Brayton cycle, and Stirling cycle.

English, R. E.

1984-01-01

305

Ocean Engineering Power Systems.  

National Technical Information Service (NTIS)

The text presents the basic thermodynamic principles and considerations necessary for the understanding of power systems in the ocean environment. These are illustrated by the development of specific application examples thereby presented the theory in a ...

A. D. Carmichael

1974-01-01

306

AC power system breadboard  

NASA Technical Reports Server (NTRS)

The object of this program was to design, build, test, and deliver a high-frequency (20-kHz) Power System Breadboard which would electrically approximate a pair of dual redundant power channels of an IOC Space Station. This report describes that program, including the technical background, and discusses the results, showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment has been completed and delivered to LeRC, where it is operating as a part of the Space Station Power System Test Facility.

Wappes, Loran J.; Sundberg, R.; Mildice, J.; Peterson, D.; Hushing, S.

1987-01-01

307

Solar Powered Refrigeration System  

NASA Astrophysics Data System (ADS)

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Ewert, Michael K.; Bergeron, David J., III

2002-09-01

308

Solar Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

309

Power system load modelling  

Microsoft Academic Search

This paper describes the progress that has been made by the authors in developing a device and a technique for power system load modelling. The applications developed under the FACTS initiative and the system identification technique using the correlation method with pseudo random sequences (PRS) have been adopted for signal injection and load modelling. Simulation studies for load modelling using

Y. Wang; N. C. Pahalawaththa

1998-01-01

310

Proton driver power supply system  

SciTech Connect

This paper describes magnet power supply system for a proposed Proton Driver at Fermilab. The magnet power supply system consists of resonant dipole/quadrupole power supply system, quadrupole tracking, dipole correction (horizontal and vertical) and sextupole power supply systems. This paper also describes preliminary design of the power distribution system supplying 13.8 kV power to all proton Driver electrical systems.

C. Jach and D. Wolff

2002-06-03

311

Laser satellite power systems  

SciTech Connect

A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

Walbridge, E.W.

1980-01-01

312

Automated Power-Distribution System  

NASA Technical Reports Server (NTRS)

Autonomous power-distribution system includes power-control equipment and automation equipment. System automatically schedules connection of power to loads and reconfigures itself when it detects fault. Potential terrestrial applications include optimization of consumption of power in homes, power supplies for autonomous land vehicles and vessels, and power supplies for automated industrial processes.

Ashworth, Barry; Riedesel, Joel; Myers, Chris; Miller, William; Jones, Ellen F.; Freeman, Kenneth; Walsh, Richard; Walls, Bryan K.; Weeks, David J.; Bechtel, Robert T.

1992-01-01

313

Windmill power system  

SciTech Connect

The present invention relates to a windmill power system, particularly a passive solar powered windmill. Specifically, the present invention is directed to a windmill in which a solar chamber and a stack produce an upwardly flowing natural convection draft which is utilized to turn the blades of a horizontally positioned windmill. A conventional vertical windmill may also be used in conjunction with the horizontal windmill. The invention can also be used in a cogeneration system or with any heat source, with waste heat being used to heat the air in the solar chamber.

Siegel, E.A.

1985-01-01

314

Handbook of photovoltaic applications: building applications and system design considerations  

SciTech Connect

A handbook of photovoltaic applications, including building applications and system design considerations, is presented. The following topics are discussed: photovoltaic applications; their future and design considerations, understanding subsystems in photovoltaic power systems, large-scale photovoltaic system design considerations, photovoltaic concentrators and advanced cell technology, prediction of annual electricity production by photovoltaic cells, stand-alone photovoltaic manufacturing facility, design and construction experience from photovoltaic installations, determining the economic feasibility of residential systems, operational results for residential prototypes, the photovoltaic interface to the public utility, federal programs in photovoltaics: cost reduction goals and R and D results, and the photovoltaic industry.

Williams, A.F.

1986-01-01

315

Power line detection system  

DOEpatents

A short-range, radio frequency (RF) transmitting-receiving system that provides both visual and audio warnings to the pilot of a helicopter or light aircraft of an up-coming power transmission line complex. Small, milliwatt-level narrowband transmitters, powered by the transmission line itself, are installed on top of selected transmission line support towers or within existing warning balls, and provide a continuous RF signal to approaching aircraft. The on-board receiver can be either a separate unit or a portion of the existing avionics, and can also share an existing antenna with another airborne system. Upon receipt of a warning signal, the receiver will trigger a visual and an audio alarm to alert the pilot to the potential power line hazard. 4 figs.

Latorre, V.R.; Watwood, D.B.

1994-09-27

316

Power line detection system  

DOEpatents

A short-range, radio frequency (RF) transmitting-receiving system that provides both visual and audio warnings to the pilot of a helicopter or light aircraft of an up-coming power transmission line complex. Small, milliwatt-level narrowband transmitters, powered by the transmission line itself, are installed on top of selected transmission line support towers or within existing warning balls, and provide a continuous RF signal to approaching aircraft. The on-board receiver can be either a separate unit or a portion of the existing avionics, and can also share an existing antenna with another airborne system. Upon receipt of a warning signal, the receiver will trigger a visual and an audio alarm to alert the pilot to the potential power line hazard.

Latorre, Victor R. (Tracy, CA); Watwood, Donald B. (Tracy, CA)

1994-01-01

317

Solar power system  

Microsoft Academic Search

A system for generating electrical power from sunlight, comprises a focussing diffraction grating or other focussing, spectrally dispersive means and a photocell array. The diffraction grating focuses sunlight into a spectrally dispersed band. The photocell array is composed of cells with different spectral sensitivities, located in positions in the dispersed band corresponding to the cell spectral sensitivities so that the

Mcgrew

1980-01-01

318

Automotive power steering system  

SciTech Connect

This patent describes improvement in an automotive power steering system including a pump, a servo-valve, a steering assist fluid motor, a reservoir having a reservoir chamber therein, fluid ducts; a volume of hydraulic oil; a fluid level. The improvement comprises: means defining a fill port; a cover; means connect a gas accumulator.

VanGorder, D.H.; Wilson, K.R.

1991-04-23

319

Financial study of commercialization of solar central receiver power systems  

NASA Astrophysics Data System (ADS)

Commercialization requires that central receiver (CR) systems meet the economic criteria used by industry to select systems for capital ventures. Quantitative estimates are given of the investment required by government, utilities, and the manufacturing sector to meet the energy displacement goals for central receiver technology. Initial solar repowering and stand-alone electric utility plants will not have economic comparability with competitive energy sources. A major factor for this is that initial (first of a kind) heliostat costs will be high. As heliostat costs are reduced due to automated manufacturing economies, learning, and high volume production, central receiver technology will become more competitive. Under this task, several scenarios (0.1, 0.5, and 1.0 quad/y) were evaluated to determine the effect on commercial attractiveness and to determine the cost to government to bring about commercialization of solar central receivers.

1981-03-01

320

Heatpipe power system development  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project was to develop a design approach that could enable the development of near-term, low-cost, space fission-power systems. Sixteen desired attributes were identified for such systems and detailed analyses were performed to verify that they are feasible. Preliminary design work was performed on one concept, the Heatpipe Power system (HPS). As a direct result of this project, funding was obtained from the National Aeronautics and Space Administration to build and test an HPS module. The module tests went well, and they now have funding to build a bimodal module.

Houts, M.G.; Poston, D.I.

1998-12-31

321

Radioisotope Power Systems  

NSDL National Science Digital Library

This NASA webpage discusses radioisotope power systems in past, present, and future space missions. It also discusses some of the successes that the radioisotopes have had on satellite missions. The webpage also includes a timeline of past missions and their accomplishments. This site also has links to other areas of the NASA Solar System page. In these links, there are videos that explain some of the instrumentation, and some of the major accomplishments of various missions. The site includes an interactive 3-D simulation that allows users go explore the solar system and learn about past satellite missions.

Administration, National A.

2012-06-19

322

High power connection system  

DOEpatents

A high power connection system adapted for automotive environments which provides environmental and EMI shielding includes a female connector, a male connector, and a panel mount. The female connector includes a female connector base and a snap fitted female connector cover. The male connector includes a male connector base and a snap fitted male connector cover. The female connector base has at least one female power terminal cavity for seatably receiving a respective female power terminal. The male connector base has at least one male power terminal cavity for seatably receiving a respective male power terminal. The female connector is covered by a cover seal and a conductive shroud. A pair of lock arms protrude outward from the front end of the male connector base, pass through the panel mount and interface with a lever of a lever rotatably connected to the shroud to thereby mechanically assist mating of the male and female connectors. Safety terminals in the male and female connectors provide a last-to-connect-first-to-break connection with an HVIL circuit.

Schaefer, Christopher E. (Warren, OH); Beer, Robert C. (Noblesville, IN); McCall, Mark D. (Youngstown, OH)

2000-01-01

323

Maximum power point tracker for photovoltaic power plants  

SciTech Connect

The paper describes two different closed-loop control criteria for the maximum power point tracking of the voltage-current characteristic of a photovoltaic generator. The two criteria are discussed and compared, inter alia, with regard to the setting-up problems that they pose. Although a detailed analysis is not embarked upon, the paper also provides some quantitative information on the energy advantages obtained by using electronic maximum power point tracking systems, as compared with the situation in which the point of operation of the photovoltaic generator is not controlled at all. Lastly, the paper presents two high efficiency MPPT converters for experimental photovoltaic plants of the stand-alone and the grid-interconnected type.

Arcidiacono, V.; Corsi, S.; Lambri, L.

1982-09-01

324

Power systems facility  

NASA Technical Reports Server (NTRS)

In 1984, the President directed NASA to undertake the development of Space Station Freedom, the next step in a broad-based U.S. civil space program to develop space-flight capabilities and to exploit space for scientific, technological, and commercial purposes. Under that direction, NASA awarded contracts in 1985 for concept definition and preliminary design studies. Those studies have been completed and the Space Station Freedom Program is now in the final design and development phase, leading to a permanently manned space station that will be operational in the mid-1990's. Here at the Lewis Research Center, with Rocketdyne, we are developing and building the S.S. Freedom electric power system (EPS) hardware and software. A major portion of the EPS will be tested at Lewis. The Power Systems Facility was specifically designed for testing the EPS and uses the latest in testing equipment.

1989-01-01

325

Electric power transmission systems  

Microsoft Academic Search

An updated edition (from 1972) of technical aspects exhibited by electric systems which transmit power from the generator to the loads. A new area covered is the calculation of short-circuit currents due to symetrical faults and their impact on the ratings of circuit-interrupting devices. Not only have problems been added, but the use of a computer (over a wide-range of

J. R. Eaton; E. Cohen

1983-01-01

326

Advanced solar power systems  

NASA Technical Reports Server (NTRS)

The Advanced Solar Power System (ASPS) concentrator uses a technically sophisticated design and extensive tooling to produce very efficient (80 to 90%) and versatile energy supply equipment which is inexpensive to manufacture and requires little maintenance. The advanced optical design has two 10th order, generalized aspheric surfaces in a Cassegrainian configuration which gives outstanding performance and is relatively insensitive to temperature changes and wind loading. Manufacturing tolerances also have been achieved. The key to the ASPS is the direct absorption of concentrated sunlight in the working fluid by radiative transfers in a black body cavity. The basic ASPS design concepts, efficiency, optical system, and tracking and focusing controls are described.

Atkinson, J. H.; Hobgood, J. M.

1984-01-01

327

Evaluation of the Tri-Service Radiology System at the Naval Hospital, Bethesda.  

National Technical Information Service (NTIS)

The Tri-Service Medical Information Systems (TRIMIS) Program Office (TPO) has installed four initial stand-alone computer systems for support of radiology operations in Medical Treatment Facilities (MTFs). The system, known as the Tri-Service Radiology Sy...

1983-01-01

328

Lunar power systems  

NASA Technical Reports Server (NTRS)

The findings of a study on the feasibility of several methods of providing electrical power for a permanently manned lunar base are provided. Two fundamentally different methods for lunar electrical power generation are considered. One is the use of a small nuclear reactor and the other is the conversion of solar energy to electricity. The baseline goal was to initially provide 300 kW of power with growth capability to one megawatt and eventually to 10 megawatts. A detailed, day by day scenario for the establishment, build-up, and operational activity of the lunar base is presented. Also presented is a conceptual approach to a supporting transportation system which identifies the number, type, and deployment of transportation vehicles required to support the base. An approach to the use of solar cells in the lunar environment was developed. There are a number of heat engines which are applicable to solar/electric conversions, and these are examined. Several approaches to energy storage which were used by the electric power utilities were examined and those which could be used at a lunar base were identified.

1986-01-01

329

Power control system and method  

DOEpatents

A power system includes an energy harvesting device, a battery coupled to the energy harvesting device, and a circuit coupled to the energy harvesting device and the battery. The circuit is adapted to deliver power to a load by providing power generated by the energy harvesting device to the load without delivering excess power to the battery and to supplement the power generated by the energy harvesting device with power from the battery if the power generated by the energy harvesting device is insufficient to fully power the load. A method of operating the power system is also provided.

Steigerwald, Robert Louis (Burnt Hills, NY) [Burnt Hills, NY; Anderson, Todd Alan (Niskayuna, NY) [Niskayuna, NY

2008-02-19

330

Modular airborne remote sampling and sensing system (MARSSS)  

SciTech Connect

Sandia is developing a modular airborne instrumentation system for the Environmental Protection Agency. This system will allow flexibility in the choice of instruments by standardizing mountings, power supplies and sampling modes. The objective is to make it possible to perform aerial surveys from chartered aircraft that have not been adapted in a more than superficial manner. It will also allow the experimenter to tailor his choice of instruments to the specific problem. Since the equipment will have a stand-alone capability, it can be applied to other problems such as long-term unattended use at remote locations or in toxic or otherwise hazardous environments.

Woods, R.O.

1982-04-01

331

TOPEX electrical power system  

NASA Technical Reports Server (NTRS)

The TOPEX mission requirements which impact the power requirements and analyses are presented. A description of the electrical power system (EPS), including energy management and battery charging methods that were conceived and developed to meet the identified satellite requirements, is included. Analysis of the TOPEX EPS confirms that all of its electrical performance and reliability requirements have been met. The TOPEX EPS employs the flight-proven modular power system (MPS) which is part of the Multimission Modular Spacecraft and provides high reliability, abbreviated development effort and schedule, and low cost. An energy balance equation, unique to TOPEX, has been derived to confirm that the batteries will be completely recharged following each eclipse, under worst-case conditions. TOPEX uses three NASA Standard 50AH Ni-Cd batteries, each with 22 cells in series. The MPS contains battery charge control and protection based on measurements of battery currents, voltages, temperatures, and computed depth-of-discharge. In case of impending battery depletion, the MPS automatically implements load shedding.

Chetty, P. R. K.; Roufberg, Lew; Costogue, Ernest

1991-01-01

332

Power electronic devices for renewable power systems  

Microsoft Academic Search

In the past, overhead lines, cables, transformers and circuit breakers represented the core components of electric power systems. However, in light of a considerable and still increasing share of renewable energy sources in grids, a change in electricity infrastructure can be observed. Over the last decades advances in power semiconductor devices have paved the way for innovative equipment such as

Rik W. De Doncker; Christian P. Dick; Florian Mura; Thomas Butschen

2010-01-01

333

Automated Power-Distribution System  

NASA Technical Reports Server (NTRS)

Automated power-distribution system monitors and controls electrical power to modules in network. Handles both 208-V, 20-kHz single-phase alternating current and 120- to 150-V direct current. Power distributed to load modules from power-distribution control units (PDCU's) via subsystem distributors. Ring busses carry power to PDCU's from power source. Needs minimal attention. Detects faults and also protects against them. Potential applications include autonomous land vehicles and automated industrial process systems.

Thomason, Cindy; Anderson, Paul M.; Martin, James A.

1990-01-01

334

Space station power system  

NASA Technical Reports Server (NTRS)

It is pointed out that space station planning at NASA began when NASA was created in 1958. However, the initiation of the program for a lunar landing delayed the implementation of plans for a space station. The utility of a space station was finally demonstrated with Skylab, which was launched in 1972. In May 1982, the Space Station Task Force was established to provide focus and direction for space station planning activities. The present paper provides a description of the planning activities, giving particular attention to the power system. The initial space station will be required to supply 75 kW of continuous electrical power, 60 kW for the customer and 15 kW for space station needs. Possible alternative energy sources for the space station include solar planar or concentrator arrays of either silicon or gallium arsenide.

Forestieri, A. F.; Baraona, C. R.

1984-01-01

335

Storage systems for tidal power  

Microsoft Academic Search

The effective use of tidal power by a typical electrical power system requires energy storage to retime the input to meet load demand. The cost of tidal power generation is relatively high and cannot be economically absorbed by the power system as secondary energy. Its constitution is more valuable when delivered at intermediate load factors. Traditional modes of \\

J. Warnock

1974-01-01

336

Power Systems Development Facility  

SciTech Connect

This report discusses Test Campaign TC12 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (SW) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). While operating as a gasifier, either air or oxygen can be used as the oxidant. Test run TC12 began on May 16, 2003, with the startup of the main air compressor and the lighting of the gasifier start-up burner. The Transport Gasifier operated until May 24, 2003, when a scheduled outage occurred to allow maintenance crews to install the fuel cell test unit and modify the gas clean-up system. On June 18, 2003, the test run resumed when operations relit the start-up burner, and testing continued until the scheduled end of the run on July 14, 2003. TC12 had a total of 733 hours using Powder River Basin (PRB) subbituminous coal. Over the course of the entire test run, gasifier temperatures varied between 1,675 and 1,850 F at pressures from 130 to 210 psig.

None

2003-07-01

337

Electrical Power Systems for MARS.  

National Technical Information Service (NTIS)

Electrical power system options for Mars Manned Modules and Mars Surface Bases were evaluated for both near-term and advanced performance potential. The power system options investigated for the Mission Modules include photovoltaics, solar thermal, nuclea...

R. J. Giudici

1986-01-01

338

Security Architecture Based on Trust Management for Pervasive Computing Systems.  

National Technical Information Service (NTIS)

Traditionally, stand-alone computers and small networks rely on user authentication and access control to provide security. These physical methods use system-based controls to verify the identity of a person or process, explicitly enabling or restricting ...

L. Kagal J. Undercoffer F. Perich A. Joshi T. Finin

2005-01-01

339

Power Systems Development Facility  

SciTech Connect

This report discusses Test Campaign TC15 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Power Generation, Inc. (SPG) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or gasifier using a particulate control device (PCD). While operating as a gasifier, either air or oxygen can be used as the oxidant. Test run TC15 began on April 19, 2004, with the startup of the main air compressor and the lighting of the gasifier startup burner. The Transport Gasifier was shutdown on April 29, 2004, accumulating 200 hours of operation using Powder River Basin (PRB) subbituminous coal. About 91 hours of the test run occurred during oxygen-blown operations. Another 6 hours of the test run was in enriched-air mode. The remainder of the test run, approximately 103 hours, took place during air-blown operations. The highest operating temperature in the gasifier mixing zone mostly varied from 1,800 to 1,850 F. The gasifier exit pressure ran between 200 and 230 psig during air-blown operations and between 110 and 150 psig in oxygen-enhanced air operations.

Southern Company Services

2004-04-30

340

Main Injector power distribution system  

SciTech Connect

The paper describes a new power distribution system for Fermilab's Main Injector. The system provides 13.8 kV power to Main Injector accelerator (accelerator and conventional loads) and is capable of providing power to the rest of the laboratory (backfeed system). Design criteria, and features including simulation results are given.

Cezary Jach and Daniel Wolff

2002-06-03

341

NREL helps bring PV power to Brazil  

SciTech Connect

In the developing world, approximately 70% of the population, or two billion people, live without access to electrical power. In Brazil, about 20% of the population, or 36 million people, live in remote areas not served by electric utility lines. Small, stand-alone photovoltaic (PV) systems for specific applications are an ideal, cost-effective way to provide basic services to rural Brazilians. To help meet this opportunity for photovoltaic-powered electrification, the National Renewable Energy Laboratory (NREL) is assisting the Department of Energy (DOE) and the Federal Republic of Brazil in carrying out a landmark agreement to install more than 1000 small photovoltaic systems in rural Brazil. This agreement brings much-needed electricity to rural homes and schools in two northeastern Brazilian states. And a recent visit to Brazil by DOE and NREL personnel has resulted in the expansion of the joint project into three additional states.

Not Available

1993-01-01

342

Homopolar generator power supply system  

Microsoft Academic Search

A high-energy, high-current homopolar generator pulsed power supply system that is compact and field portable. The power supply system includes a homopolar generator (HPG), an auxiliary supply and drive system, both mounted on a skid frame, and a control system coupled to the HPG and drive system. The homopolar generator has a split rotor with insulation between the halves and

W. F. Weldon; J. H. Gully

1985-01-01

343

Introduction to Spectroscopy PowerPoint Presentation  

NSDL National Science Digital Library

This is a downloadable PowerPoint presentation about spectroscopy. Learners read and/or hear about the science of spectroscopy, what a spectrum is, and how spectroscopy is important to astronomy. This PowerPoint accompanies the Stanford Solar Center's Build Your Own Spectroscope activity, but it can be used as a stand-alone presentation for learners.

344

Development of a multiplane multispeed balancing system for turbine systems  

NASA Technical Reports Server (NTRS)

A prototype high speed balancing system was developed for assembled gas turbine engine modules. The system permits fully assembled gas turbine modules to be operated and balanced at selected speeds up to full turbine speed. The balancing system is a complete stand-alone system providing all necesary lubrication and support hardware for full speed operation. A variable speed motor provides the drive power. A drive belt and gearbox provide rotational speeds up to 21,000 rpm inside a vacuum chamber. The heart of the system is a dedicated minicomputer with attendant data acquisition, storage and I/O devices. The computer is programmed to be completely interactive with the operator. The system was installed at CCAD and evaluated by testing 20 T55 power turbines and 20 T53 power turbines. Engine test results verified the performance of the high speed balanced turbines.

Martin, M. R.

1984-01-01

345

Vision-based position measurement system for indoor mobile robots  

SciTech Connect

This paper discusses a stand-alone position measurement system for mobile nuclear waste management robots traveling in warehouses. The task is to provide two-dimensional position information to help the automated guided vehicle (AGV) guide itself along the aisle`s centerline and mark the location of defective barrels containing low-level radiation. The AGV is 0.91 m wide and must travel along straight aisles 1.12 m wide and up to 36 m long. Radioactive testing limits the AGV`s speed to 25 mm/s. The design objectives focus on cost, power consumption, accuracy, and robustness.

Schreiber, M.J.; Dickerson, S.

1994-12-31

346

Operational performance of the photovoltaic-powered grain mill and water pump at Tangaye, Upper Volta  

NASA Technical Reports Server (NTRS)

The first two years of operation of a stand alone photovoltaic (PV) power system for the village of Tangaye, Upper Volta in West Africa are described. The purpose of the experiment was to demonstrate that PV systems could provide reliable electrical power for multiple use applications in remote areas where local technical expertise is limited. The 1.8 kW (peak) power system supplies 120-V (d.c.) electrical power to operate a grain mill, a water pump, and mill building lights for the village. The system was initially sized to pump a part of the village water requirements from an existing improved well, and to meet a portion of the village grain grinding requirements. The data, observations, experiences, and conclusions developed during the first two years of operation are discussed. Reports of tests of the mills used in the project are included.

Martz, J. E.; Ratajczak, A. F.; Delombard, R.

1982-01-01

347

Operational performance of the photovoltaic-powered grain mill and water pump at Tangaye, Upper Volta  

SciTech Connect

The first two years of operation of a stand alone photovoltaic (PV) power system for the village of Tangaye, Upper Volta in West Africa are described. The purpose of the experiment was to demonstrate that PV systems could provide reliable electrical power for multiple use applications in remote areas where local technical expertise is limited. The 1.8 kW (peak) power system supplies 120-V (d.c.) electrical power to operate a grain mill, a water pump, and mill building lights for the village. The system was initially sized to pump a part of the village water requirements from an existing improved well, and to meet a portion of the village grain grinding requirements. The data, observations, experiences, and conclusions developed during the first two years of operation are discussed. Reports of tests of the mills used in the project are included.

Martz, J.E.; Ratajczak, A.F.; Delombard, R.

1982-02-01

348

Power Transfer in Physical Systems.  

ERIC Educational Resources Information Center

Explores the power transfer using (1) a simple electric circuit consisting of a power source with internal resistance; (2) two different mechanical systems (gravity driven and constant force driven); (3) ecological examples; and (4) a linear motor. (YP)

Kaeck, Jack A.

1990-01-01

349

Performance evaluation of adding ethanol production into an existing combined heat and power plant.  

PubMed

In this paper, the configuration and performance of a polygeneration system are studied by modelling the integration of a lignocellulosic wood-to-ethanol process with an existing combined heat and power (CHP) plant. Data from actual plants are applied to validate the simulation models. The integrated polygeneration system reaches a total efficiency of 50%, meeting the heating load in the district heating system. Excess heat from the ethanol production plant supplies 7.9 MW to the district heating system, accounting for 17.5% of the heat supply at full heating load. The simulation results show that the production of ethanol from woody biomass is more efficient when integrated with a CHP plant compared to a stand-alone production plant. The total biomass consumption is reduced by 13.9% while producing the same amounts of heat, electricity and ethanol fuel as in the stand-alone configurations. The results showed that another feature of the integrated polygeneration system is the longer annual operating period compared to existing cogeneration. Thus, the renewable electricity production is increased by 2.7% per year. PMID:19758800

Starfelt, F; Thorin, E; Dotzauer, E; Yan, J

2010-01-01

350

Optimalisatie en ontwerp van een pv/accu-systeem met back-upgenerator. (Optimization and design of a photovoltaic/accumulator system with aback-up generator).  

National Technical Information Service (NTIS)

Four different options for stand-alone energy supply systems havebeen compared to find out under which conditions application of aphotovoltaic battery system with back-up generator is economicallyfeasible. The options are: petrol generator; petrol generat...

V. A. P. Van Dijk E. A. Alsema

1989-01-01

351

Development of power quality diagnosis system for power quality improvement  

Microsoft Academic Search

This paper represents the structure and functions of total power quality data management system including power quality monitoring system (PQMS), GUI system, and PQ diagnosis system. PQMS characterizes RMS value, harmonics, and frequency, and detects power quality (PQ) events. GUI system manages and stores power quality data received from a number of PQMSs and displays the power quality trends and

Il-Yop Chung; Dong-Jun Won; Joong-Moon Kim; Seon-Ju Ahn; Seung-Il Moon; Jang-Cheol Seo; Jong-Woong Choe

2003-01-01

352

POWER SYSTEMS DEVELOPMENT FACILITY  

SciTech Connect

This report discusses test campaign GCT3 of the Halliburton KBR transport reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The transport reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using one of two possible particulate control devices (PCDs). The transport reactor was operated as a pressurized gasifier during GCT3. GCT3 was planned as a 250-hour test run to commission the loop seal and continue the characterization of the limits of operational parameter variations using a blend of several Powder River Basin coals and Bucyrus limestone from Ohio. The primary test objectives were: (1) Loop Seal Commissioning--Evaluate the operational stability of the loop seal with sand and limestone as a bed material at different solids circulation rates and establish a maximum solids circulation rate through the loop seal with the inert bed. (2) Loop Seal Operations--Evaluate the loop seal operational stability during coal feed operations and establish maximum solids circulation rate. Secondary objectives included the continuation of reactor characterization, including: (1) Operational Stability--Characterize the reactor loop and PCD operations with short-term tests by varying coal feed, air/coal ratio, riser velocity, solids circulation rate, system pressure, and air distribution. (2) Reactor Operations--Study the devolatilization and tar cracking effects from transient conditions during transition from start-up burner to coal. Evaluate the effect of process operations on heat release, heat transfer, and accelerated fuel particle heat-up rates. Study the effect of changes in reactor conditions on transient temperature profiles, pressure balance, and product gas composition. (3) Effects of Reactor Conditions on Syngas Composition--Evaluate the effect of air distribution, steam/coal ratio, solids circulation rate, and reactor temperature on CO/CO{sub 2} ratio, H{sub 2}/converted carbon ratio, gasification rates, carbon conversion, and cold and hot gas efficiencies. Test run GCT3 was started on December 1, 2000, with the startup of the thermal oxidizer fan, and was completed on February 1, 2001. This test was conducted in two parts; the loop seal was commissioned during the first part of this test run from December 1 through 15, which consisted of hot inert solids circulation testing. These initial tests provided preliminary data necessary to understand different parameters associated with the operation and performance of the loop seal. The loop seal was tested with coal feed during the second part of the test run and additional data was gathered to analyze reactor operations and to identify necessary modifications to improve equipment and process performance. In the second part of GCT3, the gasification portion of the test, from January 20 to February 1, 2001, the mixing zone and riser temperatures were varied between 1,675 and 1,825 F at pressures ranging from 200 to 240 psig. There were 306 hours of solid circulation and 184 hours of coal feed attained in GCT3.

Unknown

2002-05-01

353

US electric power system reliability  

NASA Astrophysics Data System (ADS)

Electric energy supply, transmission and distribution systems are investigated in order to determine priorities for legislation. The status and the outlook for electric power reliability are discussed.

354

Power System State of Health  

NASA Astrophysics Data System (ADS)

Understanding the state of a polar station's power system can be critical to a successful long-term deployment. Knowing how the system is functioning, prior to service, is key to proper logistics, scheduling and the service performed during a visit. A full record of power system performance is key to proper analysis of the health of the power system. The design of a power system with monitoring is a balance of components to gather information while still trying to keep complexity low. To properly incorporate a system to analyze a stations power system a firm understanding of how the power components function in polar environments as well as communication to data acquisition and / or telemetry is needed. For example designers will need to know how a station's power storage system will change in colder environments then manufactures standard design criteria. This would include the reduced available capacity, change in the mean time between failure and possible new failure modes. This understanding coupled with a system that would collect key information on the state of health of the power system will provide crucial insight in to what service is needed to keep the station functioning.

Carpenter, P.

2012-12-01

355

Optimizal design and control strategies for novel Combined Heat and Power (CHP) fuel cell systems. Part II of II, case study results.  

SciTech Connect

Innovative energy system optimization models are deployed to evaluate novel fuel cell system (FCS) operating strategies, not typically pursued by commercial industry. Most FCS today are installed according to a 'business-as-usual' approach: (1) stand-alone (unconnected to district heating networks and low-voltage electricity distribution lines), (2) not load following (not producing output equivalent to the instantaneous electrical or thermal demand of surrounding buildings), (3) employing a fairly fixed heat-to-power ratio (producing heat and electricity in a relatively constant ratio to each other), and (4) producing only electricity and no recoverable heat. By contrast, models discussed here consider novel approaches as well. Novel approaches include (1) networking (connecting FCSs to electrical and/or thermal networks), (2) load following (having FCSs produce only the instantaneous electricity or heat demanded by surrounding buildings), (3) employing a variable heat-to-power ratio (such that FCS can vary the ratio of heat and electricity they produce), (4) co-generation (combining the production of electricity and recoverable heat), (5) permutations of these together, and (6) permutations of these combined with more 'business-as-usual' approaches.

Colella, Whitney G.

2010-04-01

356

Optimal design and control strategies for novel combined heat and power (CHP) fuel cell systems. Part II of II, case study results.  

SciTech Connect

Innovative energy system optimization models are deployed to evaluate novel fuel cell system (FCS) operating strategies, not typically pursued by commercial industry. Most FCS today are installed according to a 'business-as-usual' approach: (1) stand-alone (unconnected to district heating networks and low-voltage electricity distribution lines), (2) not load following (not producing output equivalent to the instantaneous electrical or thermal demand of surrounding buildings), (3) employing a fairly fixed heat-to-power ratio (producing heat and electricity in a relatively constant ratio to each other), and (4) producing only electricity and no recoverable heat. By contrast, models discussed here consider novel approaches as well. Novel approaches include (1) networking (connecting FCSs to electrical and/or thermal networks), (2) load following (having FCSs produce only the instantaneous electricity or heat demanded by surrounding buildings), (3) employing a variable heat-to-power ratio (such that FCS can vary the ratio of heat and electricity they produce), (4) co-generation (combining the production of electricity and recoverable heat), (5) permutations of these together, and (6) permutations of these combined with more 'business-as-usual' approaches. The detailed assumptions and methods behind these models are described in Part I of this article pair.

Colella, Whitney G.

2010-06-01

357

Mobile nuclear power systems  

NASA Astrophysics Data System (ADS)

Nuclear reactors where the energy comes from nuclear fission and isotopic generators utilizing the energy of the decay of suitable isotopes are discussed. The reactors are used as power sources on board nuclear submarines and other warships, as well as in space and in remote places. Their thermal power ranges from 30 KWth in a satellite to 175 MWth on board an aircraft carrier. Isotopic generators are suitable only for small power demands and are used on board satellites and spaceprobes, automatic weather stations, lighthouses, and marine installations for navigation and observation.

Andersson, Bengt

1988-11-01

358

Nanosatellite Power System Considerations  

NASA Technical Reports Server (NTRS)

The capability to build complex electronic functions into compact packages is opening the path to miniature satellites on the order of 1 kg mass, 10 cm across, packed with the computing processors, motion controllers, measurement sensors, and communications hardware necessary for operation. Power generation will be from short strings of silicon or gallium arsenide-based solar photovoltaic cells with the array power maximized by a peak power tracker (PPT). Energy storage will utilize a low voltage battery with nickel cadmium or lithium ion cells as the most likely selections for rechargeables and lithium (MnO2-Li) primary batteries for one shot short missions.

Robyn, M.; Thaller, L.; Scott, D.

1995-01-01

359

The space station power system  

NASA Technical Reports Server (NTRS)

The manned space station is the next major NASA program. It presents many challenges to the power system designers. The power system in turn is a major driver on the overall configuration. In this paper, the major requirements and guidelines that affect the station configuration and the power system are explained. The evolution of the space station power system from the NASA program development-feasibility phase through the current preliminary design phase is described. Several early station concepts, both fanciful and feasible, are described and linked to the present concept. The recently completed Phase B trade study selections of photovoltaic system technologies are described in detail. A summary of the present solar dynamic and power management and distribution systems is also given for completeness.

Baraona, C. R.

1986-01-01

360

Wave Power Systems.  

National Technical Information Service (NTIS)

Ocean wave power is worth investigating as a useable, renewable, alternative energy source. This summary suggests that both Salter cams and Cockerell rafts can be designed to convert wave motion to relative mechanical motion and mechanical forces. Mooring...

N. Doelling

1979-01-01

361

Space station electrical power system  

NASA Technical Reports Server (NTRS)

The purpose of this paper is to describe the design of the Space Station Electrical Power System. This includes the Photovoltaic and Solar Dynamic Power Modules as well as the Power Management and Distribution System (PMAD). In addition, two programmatic options for developing the Electrical Power System will be presented. One approach is defined as the Enhanced Configuration and represents the results of the Phase B studies conducted by the NASA Lewis Research Center over the last two years. Another option, the Phased Program, represents a more measured approach to reaching about the same capability as the Enhanced Configuration.

Labus, Thomas L.; Cochran, Thomas H.

1987-01-01

362

Photovoltaic power system reliability considerations  

NASA Technical Reports Server (NTRS)

An example of how modern engineering and safety techniques can be used to assure the reliable and safe operation of photovoltaic power systems is presented. This particular application is for a solar cell power system demonstration project designed to provide electric power requirements for remote villages. The techniques utilized involve a definition of the power system natural and operating environment, use of design criteria and analysis techniques, an awareness of potential problems via the inherent reliability and FMEA methods, and use of fail-safe and planned spare parts engineering philosophy.

Lalli, V. R.

1980-01-01

363

TPX power systems design overview.  

National Technical Information Service (NTIS)

The power systems for the Tokamak Physics Experiment (TPX) supply the Toroidal Field (TF). Poloidal Field (PF), Field Error Correction (FEC), and Fast Vertical Position Control (FVPC) coil systems, the Neutral Beam (NB), Ion Cyclotron (IC), Lower Hybrid (...

C. Neumeyer G. Bronner E. Lu S. Ramakrishnan M. Jackson

1993-01-01

364

Power quality load management for large spacecraft electrical power systems  

NASA Technical Reports Server (NTRS)

In December, 1986, a Center Director's Discretionary Fund (CDDF) proposal was granted to study power system control techniques in large space electrical power systems. Presented are the accomplishments in the area of power system control by power quality load management. In addition, information concerning the distortion problems in a 20 kHz ac power system is presented.

Lollar, Louis F.

1988-01-01

365

Electrical power system WP04  

Microsoft Academic Search

Viewgraphs on Space Station Freedom Electrical Power System (EPS) WP-40 are presented. Topics covered include: key EPS technical requirements; photovoltaic power module systems; solar array assembly; blanket containment box and box positioning subassemblies; solar cell; bypass diode assembly; Kapton with atomic oxygen resistant coating; sequential shunt unit; gimbal assembly; energy storage subsystem; thermal control subsystem; direct current switching unit; integrated

Donald L. Nored

1990-01-01

366

Power System Stability.  

National Technical Information Service (NTIS)

The following papers are included: exact Lagrangians for linear nonconservative systems; linear nonconservative systems with asymmetric parameters derivable from a Lagrangian; some remarks on the derivability of linear nonconservative systems from a Lagra...

1984-01-01

367

Electrical power systems for Mars  

NASA Astrophysics Data System (ADS)

Electrical power system options for Mars Manned Modules and Mars Surface Bases were evaluated for both near-term and advanced performance potential. The power system options investigated for the Mission Modules include photovoltaics, solar thermal, nuclear reactor, and isotope power systems. Options discussed for Mars Bases include the above options with the addition of a brief discussion of open loop energy conversion of Mars resources, including utilization of wind, subsurface thermal gradients, and super oxides. Electrical power requirements for Mission Modules were estimated for three basic approaches: as a function of crew size; as a function of electric propulsion; and as a function of transmission of power from an orbiter to the surface of Mars via laser or radio frequency. Mars Base power requirements were assumed to be determined by production facilities that make resources available for follow-on missions leading to the establishment of a permanently manned Base. Requirements include the production of buffer gas and propellant production plants.

Giudici, Robert J.

1986-05-01

368

Reactive Power Compensating System.  

DOEpatents

The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

1985-01-04

369

Satellite power system operations  

Microsoft Academic Search

A projection of the electrical energy demands over the next 30 to 50 years, coupled with reasonable assessments of known or developable energy sources, indicates that a shortage of electrical energy will occur about the turn of the century. Recognizing the criticality of such a shortage, the Department of Energy is currently evaluating alternative power generation concepts. One of these

F. L. Pugh; A. I. Gordon

1980-01-01

370

Power system requirements  

NASA Technical Reports Server (NTRS)

An overview of electrical power requirements for each mission of a baseline and alternate plan for space activities in the 1990-2035 timeframe is presented. The specific missions included low earth orbit (LEO), geosynchronous earth orbit (GEO), lunar, Mars, and asteroid related projects.

Conway, Edmund J.

1992-01-01

371

Railway Power SCADA System Commissioning \\  

Microsoft Academic Search

The Mass Transit Railway Corporation Ltd., installed and commissioned their first computer based Power Remote Control System in the late 1980s. The system was successfully replaced in February 2000. The paper describes the methodology adopted to prepare and facilitate the transition of the replacement computer based control system into operational service and a system review following one year of service

Ian M. Hampton; K. Lam

2001-01-01

372

Overview of power loss measurement techniques in power electronics systems  

Microsoft Academic Search

Measuring power loss accurately is of great importance for power electronics systems design and for assessing system performance and reliability. This paper reviews various power loss measurement techniques in power electronics systems. A brief overview of electrical methods for loss measurements is given. Calorimetric methods, the most accurate of all instruments for measuring power loss, are described along with their

Chucheng Xiao; Gang Chen; W. G. Odendaal

2002-01-01

373

Space power systems technology  

NASA Technical Reports Server (NTRS)

Reported here is a series of studies which examine several potential catalysts and electrodes for some fuel cell systems, some materials for space applications, and mathematical modeling and performance predictions for some solid oxide fuel cells and electrolyzers. The fuel cell systems have a potential for terrestrial applications in addition to solar energy conversion in space applications. Catalysts and electrodes for phosphoric acid fuel cell systems and for polymer electrolyte membrane (PEM) fuel cell and electrolyzer systems were examined.

Coulman, George A.

1994-01-01

374

Shunt regulation electric power system  

NASA Technical Reports Server (NTRS)

A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

Wright, W. H.; Bless, J. J. (inventors)

1971-01-01

375

Power generation systems and methods  

NASA Technical Reports Server (NTRS)

A power generation system includes a plurality of submerged mechanical devices. Each device includes a pump that can be powered, in operation, by mechanical energy to output a pressurized output liquid flow in a conduit. Main output conduits are connected with the device conduits to combine pressurized output flows output from the submerged mechanical devices into a lower number of pressurized flows. These flows are delivered to a location remote of the submerged mechanical devices for power generation.

Jones, Jack A. (Inventor); Chao, Yi (Inventor)

2011-01-01

376

Wind power electrical generator system  

Microsoft Academic Search

A wind power electrical generator system having improved efficiency including a wind mill which activates an air compressor to generate a supply of pressurized air. An air motor activated by the supply of pressurized air drives a generator to produce electrical power. A waste air recovery mechanism, activated by the waste air from the air motor produces rotary energy assisting

Allison

1984-01-01

377

Electric-Power System Simulator  

NASA Technical Reports Server (NTRS)

Shows different combinations of generation, storage, and load components: display, video monitor with keyboard input to microprocessor, and video monitor for display of load curves and power generation. Planning tool for electric utilities, regulatory agencies, and laymen in understanding basics of electric-power systems operation.

Caldwell, R. W.; Grumm, R. L.; Biedebach, B. L.

1984-01-01

378

Power turbine ventilation system  

NASA Technical Reports Server (NTRS)

Air control mechanism within a power turbine section of a gas turbine engine. The power turbine section includes a rotor and at least one variable pitch propulsor blade. The propulsor blade is coupled to and extends radially outwardly of the rotor. A first annular fairing is rotatable with the propulsor blade and interposed between the propulsor blade and the rotor. A second fairing is located longitudinally adjacent to the first fairing. The first fairing and the second fairing are differentially rotatable. The air control mechanism includes a platform fixedly coupled to a radially inner end of the propulsor blade. The platform is generally positioned in a first opening and a first fairing. The platform and the first fairing define an outer space. In a first position corresponding with a first propulsor blade pitch, the platform is substantially conformal with the first fairing. In a second position corresponding with the second propulsor blade pitch, an edge portion of the platform is displaced radially outwardly from the first fairing. When the blades are in the second position and rotating about the engine axis, the displacement of the edge portion with respect to the first fairing allows air to flow from the outer space to the annular cavity.

Wakeman, Thomas G. (Inventor); Brown, Richard W. (Inventor)

1991-01-01

379

Solar Thermal Electric Power Systems.  

National Technical Information Service (NTIS)

Results of research to identify cost effective solar thermal electric power systems are given. Parametric performance and cost models were developed for concentrating collector, heat transport, and heat storage subsystems. Dynamic programming methods to s...

1974-01-01

380

Optical Power Source Control System.  

National Technical Information Service (NTIS)

An optical power source control system having a four port optical coupler, an optical receiver and associated comparator circuits operably connected to the optical transmission line connecting the source to an output connector. When the output connector i...

C. R. Husbands

1981-01-01

381

Water Powered Bioassay System.  

National Technical Information Service (NTIS)

This project addresses critical technologies, including the acquisition, metering, buffering, delivery and assay for the processing of bio- fluids that enable the complete integration of microfluidic chips into systems. An all-plastic micromachined water-...

L. Lin

2004-01-01

382

Power enhanced frequency conversion system  

NASA Technical Reports Server (NTRS)

A frequency conversion system includes at least one source providing a first near-IR wavelength output including a gain medium for providing high power amplification, such as double clad fiber amplifier, a double clad fiber laser or a semiconductor tapered amplifier to enhance the power output level of the near-IR wavelength output. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Ra-man/Brillouin amplifier or oscillator between the high power source and the NFM device.

Sanders, Steven (Inventor); Lang, Robert J. (Inventor); Waarts, Robert G. (Inventor)

2001-01-01

383

Dynamic Isotope Power System, Integrated System Test  

Microsoft Academic Search

The Dynamic Isotope Power System (DIPS) can supply three to four times more electrical power than Radioisotope Thermoelectric Generators (RTGs) for the same amount of Pu-238 fuel. The available electrical power can be used to drive propellant-efficient electric thrusters, which would enable and\\/or significantly enhance the capabilities of interplanetary missions. Because of this, the DIPS program has been reviewing the

William D. Otting; Maribeth E. Hunt; Thomas L. Ashe

1994-01-01

384

The ac power system testbed  

NASA Technical Reports Server (NTRS)

The object of this program was to design, build, test, and deliver a high frequency (20 kHz) Power System Testbed which would electrically approximate a single, separable power channel of an IOC Space Station. That program is described, including the technical background, and the results are discussed showing that the major assumptions about the characteristics of this class of hardware (size, mass, efficiency, control, etc.) were substantially correct. This testbed equipment was completed and delivered and is being operated as part of the Space Station Power System Test Facility.

Mildice, J.; Sundberg, R.

1987-01-01

385

Analysis methods for wind turbine control and electrical system dynamics  

NASA Technical Reports Server (NTRS)

The integration of new energy technologies into electric power systems requires methods which recognize the full range of dynamic events in both the new generating unit and the power system. Since new energy technologies are initially perceived as small contributors to large systems, little attention is generally paid to system integration, i.e. dynamic events in the power system are ignored. As a result, most new energy sources are only capable of base-load operation, i.e. they have no load following or cycling capability. Wind turbines are no exception. Greater awareness of this implicit (and often unnecessary) limitation is needed. Analysis methods are recommended which include very low penetration (infinite bus) as well as very high penetration (stand-alone) scenarios.

Hinrichsen, E. N.

1995-01-01

386

Thruster models for NEP system analysis  

NASA Technical Reports Server (NTRS)

There are currently no thruster modeling codes that can be integrated with power system codes for full propulsion system modeling. Most existing thruster models were written from a 'stand alone' viewpoint, assuming the user is performing analyses on thruster performance alone. The goal of the present modeling effort is to develop thruster codes that model performance and scaling as a function of mission and system inputs, rather than in terms of more elemental physical parameters. System level parameters of interest are as follows: performance, such as specific impulse and efficency; terminal characteristics, such as voltage or current; and mass. Specific impulse and efficiency couple with mission analyses, while terminal characteristics allow integration with power systems. Additional information on lifetime and operation may be required for detailed designs.

Gilland, Jim

1993-01-01

387

The Ames Power Monitoring System  

NASA Technical Reports Server (NTRS)

The Ames Power Monitoring System (APMS) is a centralized system of power meters, computer hardware, and specialpurpose software that collects and stores electrical power data by various facilities at Ames Research Center (ARC). This system is needed because of the large and varying nature of the overall ARC power demand, which has been observed to range from 20 to 200 MW. Large portions of peak demand can be attributed to only three wind tunnels (60, 180, and 100 MW, respectively). The APMS helps ARC avoid or minimize costly demand charges by enabling wind-tunnel operators, test engineers, and the power manager to monitor total demand for center in real time. These persons receive the information they need to manage and schedule energy-intensive research in advance and to adjust loads in real time to ensure that the overall maximum allowable demand is not exceeded. The APMS (see figure) includes a server computer running the Windows NT operating system and can, in principle, include an unlimited number of power meters and client computers. As configured at the time of reporting the information for this article, the APMS includes more than 40 power meters monitoring all the major research facilities, plus 15 Windows-based client personal computers that display real-time and historical data to users via graphical user interfaces (GUIs). The power meters and client computers communicate with the server using Transmission Control Protocol/Internet Protocol (TCP/IP) on Ethernet networks, variously, through dedicated fiber-optic cables or through the pre-existing ARC local-area network (ARCLAN). The APMS has enabled ARC to achieve significant savings ($1.2 million in 2001) in the cost of power and electric energy by helping personnel to maintain total demand below monthly allowable levels, to manage the overall power factor to avoid low power factor penalties, and to use historical system data to identify opportunities for additional energy savings. The APMS also provides power engineers and electricians with the information they need to plan modifications in advance and perform day-to-day maintenance of the ARC electric-power distribution system.

Osetinsky, Leonid; Wang, David

2003-01-01

388

Manned spacecraft electrical power systems  

SciTech Connect

A brief history of the development of electrical power systems from the earliest manned space flights illustrates a natural trend toward growth of electrical power requirements and operational lifetimes with each succeeding space program. A review of the design philosophy and development experience associated with the Space Shuttle Orbiter electrical power system is presented, beginning with the state of technology at the conclusion of the Apollo Program. A discussion of prototype, verification, and qualification hardware is included, and several design improvements following the first Orbiter flight are described. The problems encountered, the scientific and engineering approaches used to meet the technological challenges, and the results obtained are stressed. Major technology barriers and their solutions are discussed, and a brief Orbiter flight experience summary of early Space Shuttle missions is included. A description of projected Space Station power requirements and candidate system concepts which could satisfy these anticipated needs is presented.

Simon, W.E.; Nored, D.L.

1987-03-01

389

Dynamic Isotope Surface Power Systems  

NASA Technical Reports Server (NTRS)

The Dynamic Isotope Power Systems (DIPS) demonstration program, sponsored by the U.S. Department of Energy (DOE) with support funding from the National Aeronautics and Space Administration (NASA), is currently focused on the development of a standardized 2.5 kWe portable generator for multiple applications on the lunar or Martian surface. A variety of potential remote and mobile applications has been identified by NASA including surface rovers for both short and extended duration missions, remote power to science packages, and backup to central base power. Recent work focused on refining the 2.5 kWe design including assessing compatibility with the Martian environment to assure the design is suitable while imposing only a minor mass penalty on lunar operations. Additional work included a study performed to compare the DIPS with regenerative fuel cell systems for lunar mobile and remote power systems. Power requirements were reviewed and a modular system chosen for the comparison. Finally, a plan and cycle schematic were generated for an early demonstration of a prototypic isotope power Brayton system using the Antarctic as the test bed.

Hunt, Maribeth E.; Rovang, Richard D.; Cataldo, Robert

1991-01-01

390

Molecular Mechanics and Dynamics Characterization of an "in silico" Mutated Protein: A Stand-Alone Lab Module or Support Activity for "in vivo" and "in vitro" Analyses of Targeted Proteins  

ERIC Educational Resources Information Center

Over the past 20 years, the biological sciences have increasingly incorporated chemistry, physics, computer science, and mathematics to aid in the development and use of mathematical models. Such combined approaches have been used to address problems from protein structure-function relationships to the workings of complex biological systems.…

Chiang, Harry; Robinson, Lucy C.; Brame, Cynthia J.; Messina, Troy C.

2013-01-01

391

Overview of Power Loss Measurement Techniques in Power Electronics Systems  

Microsoft Academic Search

Measuring power loss accurately is of great importance for power electronics systems design and for assessing system performance and reliability. This paper reviews various power loss measurement techniques in power electronics systems. A brief overview of electrical methods for loss measurements is given. Calorimetric methods, which are considered the most accurate of this purpose, are described along with their implementations.

Chucheng Xiao; Gang Chen; Willem G. H. Odendaal

2007-01-01

392

Solar-Powered Refrigeration System  

NASA Astrophysics Data System (ADS)

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Ewert, Michael K.; Bergeron, David J., III

2002-10-01

393

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

394

Solar-Powered Refrigeration System  

NASA Technical Reports Server (NTRS)

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure. and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2001-01-01

395

Solar-powered cooling system  

DOEpatents

A solar-powered adsorption-desorption refrigeration and air conditioning system uses nanostructural materials made of high specific surface area adsorption aerogel as the adsorptive media. Refrigerant molecules are adsorbed on the high surface area of the nanostructural material. A circulation system circulates refrigerant from the nanostructural material to a cooling unit.

Farmer, Joseph C

2013-12-24

396

Power conditioning unit for photovoltaic power systems  

Microsoft Academic Search

Operational features and components of a power conditioning unit for interconnecting solar cell module powers with a utility grid are outlined. The two-stage unit first modifies the voltage to desired levels on an internal dc link, then inverts the current in 2 power transformers connected to a vector summation control to neutralize harmonic distortion up to the 11th harmonic. The

G. Beghin; V. T. Nguyen Phuoc

1981-01-01

397

A Novel 500kW High-Speed Turbine PM Synchronous Generator Set for Distributed Power Generation  

NASA Astrophysics Data System (ADS)

The paper presents a power generation system based on the cogeneration of heat and electricity with a novel high speed turbogenerator. The machine consists of a single stage steam turbine and a directly coupled permanent magnet synchronous generator in one constructional unit. A PWM IGBT rectifier is the load to the generator and a PWM IGBT three-phase four-wire inverter feeds the power into the low voltage mains. In order to increase the turbine efficiency at light load, variable speed operation of the turbogenerator is realized. Different control schemes for mains parallel operation and stand alone operation are presented. The control schemes allow for the use of a lookup table based control with a speed-power-characteristic or for the use of a maximum power point tracker. Measurement results from the successfully tested turbogenerator set are presented.

Wendt, Sven; Benecke, Frank; Güldner, Henry

398

Controllability and diagnosis in electric power systems  

Microsoft Academic Search

While modern electric power systems are often operated under stressed conditions, there is an increasing social demand for reliable electricity supplies. The reliable operation of a power system depends on the power system's ability to maintain a normal operating condition following a disturbance. This study focuses on two aspects of power systems: Controllability and diagnosis, both concerned with the power

Mingguo Hong

1998-01-01

399

Dynamic modeling of power systems  

SciTech Connect

Morgantown Energy Technology Center`s (METC) Process and Project Engineering (P&PE) personnel continue to refine and modify dynamic modeling or simulations for advanced power systems. P&PE, supported by Gilbert/Commonwealth, Inc. (G/C), has adapted PC/TRAX commercial dynamic software to include equipment found in advanced power systems. PC/TRAX`s software contains the equations that describe the operation of standard power plant equipment such as gas turbines, feedwater pumps, and steam turbines. The METC team has incorporated customized dynamic models using Advanced Continuous Simulation Language (ACSL) code for pressurized circulating fluidized-bed combustors, carbonizers, and other components that are found in Advanced Pressurized Fluidized-Bed Combustion (APFBC) systems. A dynamic model of a commercial-size APFBC power plant was constructed in order to determine representative operating characteristics of the plant and to gain some insight into the best type of control system design. The dynamic model contains both process and control model components. This presentation covers development of a model used to describe the commercial APFBC power plant. Results of exercising the model to simulate plant performance are described and illustrated. Information gained during the APFBC study was applied to a dynamic model of a 1-1/2 generation PFBC system. Some initial results from this study are also presented.

Reed, M.; White, J.

1995-12-01

400

Dynamic interactions between power plants and power systems  

Microsoft Academic Search

This survey is focused on the numerous dynamic interactions between power plants and power systems. Examples from two applications are used in this paper to show:•the advantages of model-based power control concepts for steam power plants, being robust against internal power-plant disturbances and external power-system disturbances, not only during normal interconnected grid operation, but also in the cases of isolated

E. Welfonder

1999-01-01

401

Integration of the Premium Power Supply on Electric Power System  

Microsoft Academic Search

This paper describes an inverter-interfaced distributed generation (DG) system that is interconnected with the electric power system (EPS). This system has two main goals such as to serve the customer with reliable electric power and to improve power quality like harmonics and voltage event. This system is interfaced through the series and the shunt inverters because inverters are effective to

Jin-Woo Park; Il-Yop Chung; Kyoung-Nam Kim; Jong-Hun Lee; Seung-Il Moon; Byung-Moon Han

2005-01-01

402

Nonlinear Behavior of CRF Device at High Power Level  

Microsoft Academic Search

This paper investigates the nonlinear behavior of CRF filters. First, measurements carried out on stand-alone resonators underline the impact of resonator size and loading layer thickness on linearity. Then, a comparison between a BAW filter and a CRF filter is presented regarding second order nonlinearities. Finally, the nonlinear behavior of CRF filters at high power levels has been investigated through

L. Mourot; P. Bar; A. Giry; S. Joblot; G. Parat; S. Bila; J.-F. Carpentier

2009-01-01

403

Pegasus power system facility upgrades  

NASA Astrophysics Data System (ADS)

Two key Pegasus systems have been recently upgraded: the Ohmic-transformer IGCT bridge control system, and the plasma-gun injector power system. The Ohmic control system contains two new microprocessor controlled components to provide an interface between the PWM controller and the IGCT bridges. An interface board conditions the command signals from the PWM controller. A splitter/combiner board routes the conditioned PWM commands to an array of IGCT bridges and interprets IGCT bridge status. This system allows for any PWM controller to safely control IGCT bridges. Future developments will include a transition to a polyphasic bridge control. This will allow for 3 to 4 times the present pulse length and provide a much higher switching frequency. The plasma gun injector system now includes active current feedback control on gun bias current via PWM buck type power supplies. Near term goals include a doubling or tripling of the applied bias voltage. Future arc bias system power supplies may include a simpler boost type system which will allow access to even higher voltages using existing low voltage energy storage systems.

Lewicki, B. T.; Kujak-Ford, B. A.; Winz, G. R.

2008-11-01

404

Nanosat Intelligent Power System Development  

NASA Technical Reports Server (NTRS)

NASA Goddard Space Flight Center is developing a class of satellites called nano-satellites. The technologies developed for these satellites will enable a class of constellation missions for the NASA Space Science Sun-Earth Connections theme and will be of great benefit to other NASA enterprises. A major challenge for these missions is meeting significant scientific- objectives with limited onboard and ground-based resources. Total spacecraft power is limited by the small satellite size. Additionally, it is highly desirable to minimize operational costs by limiting the ground support required to manage the constellation. This paper will describe how these challenges are met in the design of the nanosat power system. We will address the factors considered and tradeoffs made in deriving the nanosat power system architecture. We will discuss how incorporating onboard fault detection and correction capability yields a robust spacecraft power bus without the mass and volume penalties incurred from redundant systems and describe how power system efficiency is maximized throughout the mission duration.

Johnson, Michael A.; Beaman, Robert G.; Mica, Joseph A.; Truszkowski, Walter F.; Rilee, Michael L.; Simm, David E.

1999-01-01

405

ADVANCED POWER SYSTEMS ASH BEHAVIOR IN POWER SYSTEMS  

SciTech Connect

The overall goal of this initiative is to develop fundamental knowledge of ash behavior in power systems for the purpose of increasing power production efficiency, reducing operation and maintenance costs, and reducing greenhouse gas emissions into the atmosphere. The specific objectives of this initiative focus primarily on ash behavior related to advanced power systems and include the following: ? Determine the current status of the fundamental ash interactions and deposition formation mechanisms as already reported through previous or ongoing projects at the EERC or in the literature. ? Determine sintering mechanisms for temperatures and particle compositions that are less well known and remain for the most part undetermined. ? Identify the relationship between the temperature of critical viscosity (Tcv ) as measured in a viscometer and the crystallization occurring in the melt. ? Perform a literature search on the use of heated-stage microscopy (HSM) for examining in situ ash-sintering phenomena and then validate the use of HSM in the determination of viscosity in spherical ash particles. ? Ascertain the formation and stability of specific mineral or amorphous phases in deposits typical of advanced power systems. ? Evaluate corrosion for alloys being used in supercritical combustion systems.

CHRISTOPHER J. ZYGARLICKE; DONALD P. MCCOLLOR; JOHN P. KAY; MICHAEL L. SWANSON

1998-09-01

406

Models for multimegawatt space power systems  

SciTech Connect

This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.

Edenburn, M.W.

1990-06-01

407

The Bulk Power Transmission System of Tokyo Electric Power Company  

NASA Astrophysics Data System (ADS)

In this paper, the history and future prospects of the bulk power transmission system of Tokyo Electric Power Company (TEPCO) are presented. This paper also introduces some technical problems, which has occurred in accordance with the expansion of TEPCO's power system, and measures for ensuring stable power supply.

Kitajima, Takashi

408

The Bulk Power Transmission System of Tokyo Electric Power Company  

Microsoft Academic Search

In this paper, the history and future prospects of the bulk power transmission system of Tokyo Electric Power Company (TEPCO) are presented. This paper also introduces some technical problems, which has occurred in accordance with the expansion of TEPCO's power system, and measures for ensuring stable power supply.

Takashi Kitajima

2008-01-01

409

A Nonlinear Digital Control Solution for a DC/DC Power Converter  

NASA Technical Reports Server (NTRS)

A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

Zhu, Minshao

2002-01-01

410

Model for energy conversion in renewable energy system with hydrogen storage  

NASA Astrophysics Data System (ADS)

A dynamic model for a stand-alone renewable energy system with hydrogen storage (RESHS) is developed. In this system, surplus energy available from a photovoltaic array and a wind turbine generator is stored in the form of hydrogen, produced via an electrolyzer. When the energy production from the wind turbine and the photovoltaic array is not enough to meet the load demand, the stored hydrogen can then be converted by a fuel cell to produce electricity. In this system, batteries are used as energy buffers or for short time storage. To study the behavior of such a system, a complete model is developed by integrating individual sub-models of the fuel cell, the electrolyzer, the power conditioning units, the hydrogen storage system, and the batteries (used as an energy buffer). The sub-models are valid for transient and steady state analysis as a function of voltage, current, and temperature. A comparison between experimental measurements and simulation results is given. The model is useful for building effective algorithms for the management, control and optimization of stand-alone RESHSs.

Kélouwani, S.; Agbossou, K.; Chahine, R.

411

Damping of power oscillations in large power systems.  

National Technical Information Service (NTIS)

Much research has been done during the last twenty years about tuning of damping equipment in power systems. Damping equipment of concern in this thesis are PSSs (Power System Stabilizers), SVCs (Static Var Compensators), and HVDC (High Voltage Direct Cur...

B. Eliasson

1990-01-01

412

Modeling of power electronic systems with EMTP  

NASA Technical Reports Server (NTRS)

In view of the potential impact of power electronics on power systems, there is need for a computer modeling/analysis tool to perform simulation studies on power systems with power electronic components as well as to educate engineering students about such systems. The modeling of the major power electronic components of the NASA Space Station Freedom Electric Power System is described along with ElectroMagnetic Transients Program (EMTP) and it is demonstrated that EMTP can serve as a very useful tool for teaching, design, analysis, and research in the area of power systems with power electronic components. EMTP modeling of power electronic circuits is described and simulation results are presented.

Tam, Kwa-Sur; Dravid, Narayan V.

1989-01-01

413

Developing a Stand Alone Sun Photometer for Ships and Buoys  

NASA Technical Reports Server (NTRS)

During November and December 1995 the first Aerosol Characterization Experiment (ACE 1) was carried to characterize the aerosol physical and optical properties in the clean marine atmosphere near Tasmania in the South Pacific. As part of this effort, and with funding from this proposal, we installed a sun photometer on the R/V Discoverer and a spectro-photometer on the NOAA C-130 aircraft.

Porter, John N.

1997-01-01

414

Adaptive relay setting for stand-alone digital distance protection  

Microsoft Academic Search

Reach accuracy of a distance relay on transmission lines is adversely affected by fault resistance combined with remote-end infeed which is not measurable at the relaying point. Different network conditions correspond to different remote-end infeed behavior and in conventional setting a safety margin is necessary so as to avoid maloperation. In this paper an adaptive setting concept which can overcome

Y. Q. Xia; K. K. Li; A. K. David

1994-01-01

415

Stand-Alone Computers Supporting Learning Dialogues in Primary Classrooms  

ERIC Educational Resources Information Center

This paper focuses on three distinctive ways in which educational software can support learning dialogues in primary classrooms. After a re-capitulation of published research on Initiation, "Discussion," Response, Feedback (IDRF) exchanges, where the computer is used to stimulate discussion and then direct it through using feedback, we ask if…

Wegerif, Rupert; Littleton, Karen; Jones, Ann

2003-01-01

416

Homopolar generator power supply system  

SciTech Connect

A high-energy, high-current homopolar generator pulsed power supply system that is compact and field portable. The power supply system includes a homopolar generator (HPG), an auxiliary supply and drive system, both mounted on a skid frame, and a control system coupled to the HPG and drive system. The homopolar generator has a split rotor with insulation between the halves and a recess in the periphery. A stator ring and field coil, for producing a magnetic field through which the rotor halves make two simultaneous voltage-generating passes, are disposed within the recess in the rotor. Air-actuated brush mechanisms inside and outside the recess contact surfaces of the rotor and collect discharge current. The auxiliary supply and drive system includes a motoring system comprising hydraulic motors for driving the HPG to speed, a bearing lubrication system, a generator for energizing the field coil, and a brush actuator air supply system, all of which are driven by a prime mover. The control system comprises a logic controller for executing a prescribed sequence of steps including turning on the prime mover, initiating motoring of the HPG, energizing the field coil, and initiating the discharge of electrical current.

Weldon, W. F.; Gully, J. H.

1985-10-01

417

A contactless power supply for photovoltaic power generation system  

Microsoft Academic Search

Among the alternative energy sources, the solar energy is recognized as an important energy source and its application is increasing. Especially in future, the hybrid solar energy generation system with battery and fuel cell will be widely used as an independent distributed power generation system. In this paper, a solar power hybrid home generation system using a contactless power supply

Eun-Soo Kim; Sung-In Kang; Kwang-Ho Yoon; Yoon-Ho Kim

2008-01-01

418

Advanced aircraft electric power system  

SciTech Connect

The role of electric energy in both military and commercial aircraft increases in importance with every advancement in airframe performance and avionic technology. Microcircuits and volatile memories impact power continuity and quality, digital flight control and stability augmentation require high reliability. This paper presents the system concept, hardware development and status of the Navy program.

Segrest, J.D.

1981-01-01

419

Space station power system requirements  

NASA Technical Reports Server (NTRS)

Presented is an overview of the requirements on which the Space Station Electric Power System is based as well as a summary of the design itself. The current design, which is based on silicon photovoltaic arrays, NiH2 batteries, and 20 kHz distribution technology, meets all of the requirements.

Dunning, John W., Jr.

1988-01-01

420

Space Station power system requirements  

NASA Technical Reports Server (NTRS)

Presented is an overview of the requirements on which the Space Station Electric Power System is based as well as a summary of the design itself. The current design, which is based on silicon photovoltaic arrays, NiH2 batteries, and 20 kHz distribution technology, meets all of the requirements.

Dunning, John W., Jr.

1988-01-01

421

Robotic monitoring of power systems  

Microsoft Academic Search

Monitoring of electric power systems in real time for reliability, aging status, and presence of incipient faults requires distributed and centralized processing of large amounts of data from distributed sensor networks. To solve this task, cohesive multidisciplinary efforts are needed from such fields as sensing, signal processing, control, communications, optimization theory, and, more recently, robotics. This review paper focuses on

Bing Jiang; Alexander Mamishev

2004-01-01

422

Satellite power systems \\/SPS\\/ overview  

Microsoft Academic Search

The concept of using a number of very large satellites in geostationary equatorial orbit to convert solar energy into electricity and then to microwave energy transmitted back to earth is given a brief historical overview. The major program elements and organizational responsibilities in the DOE\\/NASA program for satellite power systems are schematized. The timetable calls for preliminary program recommendations in

R. I. Larock

1978-01-01

423

Power system dynamic response calculations  

Microsoft Academic Search

Engineers in the power industry, face the problem that, while stability is increasingly a limiting factor in secure system operation, the simulation of system dynamic response is grossly overburdening on present-day digital computing resources. Each individual response case involves the step-by-step numerical solution in the time domain of perhaps thousands of nonlinear differential-algebraic equations, at a cost of up to

B. Stott

1979-01-01

424

Bonneville, Power Administration Timing System  

NASA Technical Reports Server (NTRS)

Time is an integral part of the Bonneville Power Administration's (BPA) operational systems. Generation and power transfers are planned in advance. Utilities coordinate with each other by making these adjustments on a timed schedule. Price varies with demand, so billing is based on time. Outages for maintenance are scheduled to assure they do not interrupt reliable power delivery. Disturbance records are aligned with recorded timetags for analysis and comparison with related information. Advanced applications like traveling wave fault location and real-time phase measurement require continuous timing with high precision. Most of BPA is served by a Central Time System (CTS) at the Dittmer Control Center near Portland, OR. This system keeps time locally and supplies time to both the control center systems and field locations via a microwave signal. It is kept synchronized to national standard time and coordinated with interconnected utilities. It is the official BPA time. Powwer system control and operation is described, followed by a description of BPA timing systems including CTS, the Fault Location Acquisition Reporter, time dissemination, and phasor measurements. References are provided for further reading.

Martin, Kenneth E.

1996-01-01

425

Nanosatellite electrical power system development  

NASA Astrophysics Data System (ADS)

Nanosatellites have the potential to carry out the complex work of today's larger satellites at a fraction of the cost. Their small designs drastically reduce launch costs and allow many research projects and technology demonstration missions to be flown. The development of small satellites has created a need for smaller, lightweight electrical power systems (EPS) without compromising the power capacity. This thesis focuses on the electrical power system of the YUsend-1 mission. The work carried out in designing and developing the EPS for the YUsend mission utilizing commercial technologies is outlined. Mission modes are developed and a power budget is assigned for the different subsystems setting a baseline for how much power is needed. Different battery chemistries are analyzed in order to find a type that would suit the needs of the YUsend program. Commercially available batteries are put through space environment testing and the results are presented. The fabrication, testing, and space qualification results of solar panels using Triangular Advanced Solar Cells (TASCs) are also presented. Lastly the layout for the distribution board is developed.

Navarathinam, Nimal

426

The Failure Analysis in Traction Power System  

Microsoft Academic Search

This paper presents a failure analysis of traction power systems. The electric railway consists of traction power systems, various vehicles, operating equipment, track, overhead line and electric equipment. It is a fundamental function of traction power systems that they supply customers with acceptable reliability and high quality power. Perhaps the most commonly used reliability assessment for railway systems has been

Hyungchul Kim; Guk-Bum Heo; Hyungwoo Lee; Dong Jin Kim; Jin O. Kim

2008-01-01

427

Computation of closest bifurcations in power systems  

SciTech Connect

Voltage collapse and blackout can occur in an electric power system when load powers vary so that the system loses stability in a saddle node bifurcation. This paper computes load powers at which bifurcation occurs and which are locally closest to given operating load powers. The distance in load power parameter space to this locally closest bifurcation is an index of voltage collapse and a minimum load power margin. The computations are illustrated for several power systems. Monte-Carlo optimization techniques are applied to obtain multiple minimum load power margins. The use of load power margin sensitivities to select system controls is discussed.

Alvarado, F.; Dobson, I.; Hu, Y. (Univ. of Wisconsin, Madison, WI (United States). Electrical Computer Engineering Dept.)

1994-05-01

428

Manned spacecraft electrical power systems  

NASA Technical Reports Server (NTRS)

A brief history of the development of electrical power systems from the earliest manned space flights illustrates a natural trend toward a growth of electrical power requirements and operational lifetimes with each succeeding space program. A review of the design philosophy and development experience associated with the Space Shuttle Orbiter electrical power system is presented, beginning with the state of technology at the conclusion of the Apollo Program. A discussion of prototype, verification, and qualification hardware is included, and several design improvements following the first Orbiter flight are described. The problems encountered, the scientific and engineering approaches used to meet the technological challenges, and the results obtained are stressed. Major technology barriers and their solutions are discussed, and a brief Orbiter flight experience summary of early Space Shuttle missions is included. A description of projected Space Station power requirements and candidate system concepts which could satisfy these anticipated needs is presented. Significant challenges different from Space Shuttle, innovative concepts and ideas, and station growth considerations are discussed. The Phase B Advanced Development hardware program is summarized and a status of Phase B preliminary tradeoff studies is presented.

Simon, William E.; Nored, Donald L.

1987-01-01

429

Uninterruptible power supply cogeneration system  

SciTech Connect

A power system is described for providing an uninterruptible power supply comprising: a first generator means for supplying energy to a primary load; a second generator means connected to an electrical utility, the first and second generator means being connected by a common shaft, the first generator means being electrically isolated from the electrical utility; prime mover means connected to the common shaft, the prime mover means for supplying mechanical energy to the shaft; and controller means interposed electrically between the second generator means and the secondary external load, the controller means causing the second generator means to become disconnected from the secondary load upon interruptions in the secondary load.

Gottfried, C.F.

1987-08-11

430

Power System Optimization Codes Modified  

NASA Technical Reports Server (NTRS)

A major modification of and addition to existing Closed Brayton Cycle (CBC) space power system optimization codes was completed. These modifications relate to the global minimum mass search driver programs containing three nested iteration loops comprising iterations on cycle temperature ratio, and three separate pressure ratio iteration loops--one loop for maximizing thermodynamic efficiency, one for minimizing radiator area, and a final loop for minimizing overall power system mass. Using the method of steepest ascent, the code sweeps through the pressure ratio space repeatedly, each time with smaller iteration step sizes, so that the three optimum pressure ratios can be obtained to any desired accuracy for each of the objective functions referred to above (i.e., maximum thermodynamic efficiency, minimum radiator area, and minimum system mass). Two separate options for the power system heat source are available: 1. A nuclear fission reactor can be used. It is provided with a radiation shield 1. (composed of a lithium hydride (LiH) neutron shield and tungsten (W) gamma shield). Suboptions can be used to select the type of reactor (i.e., fast spectrum liquid metal cooled or epithermal high-temperature gas reactor (HTGR)). 2. A solar heat source can be used. This option includes a parabolic concentrator and heat receiver for raising the temperature of the recirculating working fluid. A useful feature of the code modifications is that key cycle parameters are displayed, including the overall system specific mass in kilograms per kilowatt and the system specific power in watts per kilogram, as the results for each temperature ratio are computed. As the minimum mass temperature ratio is encountered, a message is printed out. Several levels of detailed information on cycle state points, subsystem mass results, and radiator temperature profiles are stored for this temperature ratio condition and can be displayed or printed by users.

Juhasz, Albert J.

1999-01-01

431

Dynamic Isotope Power System, Integrated System Test  

NASA Astrophysics Data System (ADS)

The Dynamic Isotope Power System (DIPS) can supply three to four times more electrical power than Radioisotope Thermoelectric Generators (RTGs) for the same amount of Pu-238 fuel. The available electrical power can be used to drive propellant-efficient electric thrusters, which would enable and/or significantly enhance the capabilities of interplanetary missions. Because of this, the DIPS program has been reviewing the application of DIPS technology to the interplanetary missions in the 500 We to 1.0 kWe power range. Such a DIPS program would focus on completing an Integrated System Test (IST) of the DIPS in a simulated space environment. The DIPS IST would fully demonstrate DIPS integrated operation, long-term containment boundary integrity, and, most importantly, DIPS flight readiness. To reduce cost, schedule, and risk of the DIPS development, the design would use the DOE-developed Brayton Isotope Power System (BIPS) turboalternator compressor (TAC), which is currently being refurbished for use in the NASA-LeRC Solar Dynamic Ground Test Demonstration (SD GTD) Program. The DIPS IST, which would follow the SD GTD testing, would make use of common elements with the SD GTD wherever practical to reduce the IST cost and schedule. The components demonstrated in the IST would be flight prototypical except that full flight qualification would not be performed. For future interplanetary applications, the DIPS system would employ the identical TAC design demonstrated in the IST for all applications. Power level scalability would be achieved by scaling other loop components in a straightforward manner without technology development or requalification. This will significantly reduce costs while providing only a small scalability performance penalty.

Otting, William D.; Hunt, Maribeth E.; Ashe, Thomas L.

1994-07-01

432

Automated power distribution system hardware. [for space station power supplies  

NASA Technical Reports Server (NTRS)

An automated power distribution system testbed for the space station common modules has been developed. It incorporates automated control and monitoring of a utility-type power system. Automated power system switchgear, control and sensor hardware requirements, hardware design, test results, and potential applications are discussed. The system is designed so that the automated control and monitoring of the power system is compatible with both a 208-V, 20-kHz single-phase AC system and a high-voltage (120 to 150 V) DC system.

Anderson, Paul M.; Martin, James A.; Thomason, Cindy

1989-01-01

433

Emergency Power For Critical Items  

NASA Astrophysics Data System (ADS)

Natural disasters, such as hurricanes, floods, tornados, and tsunami, are becoming a greater problem as climate change impacts our environment. Disasters, whether natural or man made, destroy lives, homes, businesses and the natural environment. Such disasters can happen with little or no warning, leaving hundreds or even thousands of people without medical services, potable water, sanitation, communications and electrical services for up to several weeks. In our modern world, the need for electricity has become a necessity. Modern building codes and new disaster resistant building practices are reducing the damage to homes and businesses. Emergency gasoline and diesel generators are becoming common place for power outages. Generators need fuel, which may not be available after a disaster, but Photovoltaic (solar-electric) systems supply electricity without petroleum fuel as they are powered by the sun. Photovoltaic (PV) systems can provide electrical power for a home or business. PV systems can operate as utility interactive or stand-alone with battery backup. Determining your critical load items and sizing the photovoltaic system for those critical items, guarantees their operation in a disaster.

Young, William R.

2009-07-01

434

Power Conditioning Systems for High-Power, Airborne, Pulsed Applications  

Microsoft Academic Search

The power conditioning portion of the high-power study that was performed for the Air Force Aeropropulsion Laboratory by the State University of New York at Buffalo is summarized. This effort defines the power conditioning system and critical component developments which will be required to interface the airborne 10-MW to 50-MW sources defined under separate study efforts with certain loads. Power

1977-01-01

435

Seismic reliability of electrical power transmission systems  

Microsoft Academic Search

The reliability of electric power transmission systems is important for the probabilistic safety assessment of nuclear power plants under a given earthquake loading as it relates to the loss of off site power to the nuclear power plants. Here, a comprehensive model to evaluate the seismic reliability of electric power transmission systems is presented. The model provides probabilistic assessments of

J. A. Pires; A. H.-S. Ang; R. Villaverde

1996-01-01

436

Computation of closest bifurcations in power systems  

Microsoft Academic Search

Voltage collapse and blackout can occur in an electric power system when load powers vary so that the system loses stability in a saddle node bifurcation. This paper computes load powers at which bifurcation occurs and which are locally closest to given operating load powers. The distance in load power parameter space to this locally closest bifurcation is an index

Fernando Alvarado; Ian Dobson; Yi Hu

1994-01-01

437

Security for space power systems  

SciTech Connect

This paper presents an initial system security monitor (SSM) developed for the power system of a proposed National Aeronautics and Space Administration (NASA) permanently manned space station. Four types of ranked disturbances or faults to the transmission system are successively corrected by remedial action of the SSM. After each corrective action, the SSM verifies the system change has been implemented, then proceeds to examine lower priority disturbances if they persist. The SSM authority is limited by the operating state of the system, and only one correction is permitted for each scan cycle. The disturbance signals are verified by the use of a state estimator. The small network size permits use of connectivity searches of the network topology for possible corrective actions and a load flow to predict the effect of corrective actions. The data scan rate is higher than earth-based systems. Line switching actions are implemented within line cycles because thyristors are used as circuit breakers. The paper presents examples of disturbance identification and remedial action that could apply to earth-based power systems.

Kusic, G.L. (Pittsburgh Univ., PA (USA). Dept. of Electrical Engineering); Allen, W.H.; Gholdston, E.W. (Rockwell International Corp., Canoga Park, CA (USA). Rocketdyne Div.); Beach, R.F. (National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center)

1990-11-01

438

Uninterruptible power supply systems in NTT  

Microsoft Academic Search

A decentralized power system for an AC power system and a DC power system has been developed. In this system, the uninterruptible power supply (UPS) system is installed in telecommunications rooms, and is aimed at peripheral equipment in switching systems. This UPS system consists of 1 kVA add-on type inverter units, and has a maximum capacity of 5 kVA through

H. Yamashita

1990-01-01

439

Advanced Radioisotope Power Systems Segmented Thermoelectric Research  

NASA Technical Reports Server (NTRS)

Flight times are long; - Need power systems with >15 years life. Mass is at an absolute premium; - Need power systems with high specific power and scalability. 3 orders of magnitude reduction in solar irradiance from Earth to Pluto. Nuclear power sources preferable. The Overall objective is to develop low mass, high efficiency, low-cost Advanced Radioisotope Power System with double the Specific Power and Efficiency over state-of-the-art Radioisotope Thermoelectric Generators (RTGs).

Caillat, Thierry

2004-01-01

440

Power management of hybrid photovoltaic - fuel cell power systems  

Microsoft Academic Search

Photovoltaic (PV) solar energy systems are widely used as an important alternative energy source. To overcome the problem of intermittent power generation, PV power systems may be integrated with other power sources. Fuel cells are an attractive option because of high efficiency, modularity and fuel flexibility; however, one main week point is their slow dynamics. On the other hand, current

Zhenhua Jiang

2006-01-01

441

Impact of large scale wind power on power system stability  

Microsoft Academic Search

This paper presents a detailed analysis of the impact of large scale wind power generation on both the dynamic voltage stability and the transient stability of electric power systems. The following problems have been analyzed: different penetration of wind power impact on transient stability and on voltage stability (dynamic voltage stability) following a major fault in the transmission system, determination

M. El-Shimy; M. A. L. Badr; O. M. Rassem

2008-01-01

442

Wind and Solar-Powered Hybrid Prime Power Systems  

Microsoft Academic Search

During the past five years, there has been rapid development in the field of wind and solar-powered hybrid prime power systems. This paper will discuss the following three aspects of this development: A review of accepted techniques for designing and installing a hybrid alternative energy system and also the possible pitfalls one might encounter. System controllers. System controllers play a

Allan Russell

1984-01-01

443

On Power System Controlled Separation  

Microsoft Academic Search

This paper describes verification of five conjectures related to power system controlled separation. It attempts to verify that the location of uncontrolled separation (loss of synchronism or out-of-step operation) is independent of the location and severity (short-circuit duty or duration) of the initial faults, that the location depends on the prevailing network configuration and load level, and that it takes

M. M. Adibi; R. J. Kafka; Sandeep Maram; Lamine M. Mili

2006-01-01

444

Dynamic Isotope Surface Power Systems  

Microsoft Academic Search

The Dynamic Isotope Power Systems (DIPS) demonstration program, sponsored by the U.S. Department of Energy (DOE) with support funding from the National Aeronautics and Space Administration (NASA), is currently focused on the development of a standardized 2.5 kWe portable generator for multiple applications on the lunar or Martian surface. A variety of potential remote and mobile applications has been identified

Maribeth E. Hunt; Richard D. Rovang; Robert Cataldo

1991-01-01

445

Advanced secondary power system for transport aircraft  

NASA Technical Reports Server (NTRS)

A concept for an advanced aircraft power system was identified that uses 20-kHz, 440-V, sin-wave power distribution. This system was integrated with an electrically powered flight control system and with other aircraft systems requiring secondary power. The resulting all-electric secondary power configuration reduced the empty weight of a modern 200-passenger, twin-engine transport by 10 percent and the mission fuel by 9 percent.

Hoffman, A. C.; Hansen, I. G.; Beach, R. F.; Plencner, R. M.; Dengler, R. P.; Jefferies, K. S.; Frye, R. J.

1985-01-01

446

Fuel-cell powered uninterruptible power supply systems: Design considerations  

Microsoft Academic Search

A 1-kVA fuel cell powered, line-interactive uninterruptible power supply (UPS) system that employs modular (fuel cell and power converter) blocks is introduced. Two commercially available proton-exchange membrane fuel cell (25–39V, 500W) modules together with suitable dc–dc and dc–ac power electronic converter modules are employed. A supercapacitor module is also used to compensate for the instantaneous power fluctuations and to overcome

Woojin Choi; Jo. W. Howze; Prasad Enjeti

2006-01-01

447

Modeling Power Systems as Complex Adaptive Systems  

SciTech Connect

Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions.

Chassin, David P.; Malard, Joel M.; Posse, Christian; Gangopadhyaya, Asim; Lu, Ning; Katipamula, Srinivas; Mallow, J V.

2004-12-30

448

The power management reporting system  

SciTech Connect

There is no simple way to accomplish the placement of remote Energy Management System (EMS) consoles, considering the design of the current EMS. The proposed replacement EMS will provide remote console capability, however the new system is several years away. A cost effective means of providing the company with the needed data in the interim is via the corporate mainframe computer. The data is readily available anywhere there exists a mainframe terminal. PSI spent considerable time migrating both the EMS and the corporate mainframe to an environment capable of data transfer. All required technology is now in place to facilitate transfers of this nature. Management and various technical groups now use EMS data as a decision making and analysis tool. The project was a joint effort with Information Systems. Without their cooperation, the corporation could not benefit from the use of timely EMS information. This paper discusses the design and operation of what is known as the Power Management Reporting System (PMR).

Gunn, B.L. (PSI Energy, Inc., Plainfield, IN (US))

1992-01-01

449

Device system and method for miniaturized radiation spectrometer  

NASA Technical Reports Server (NTRS)

A device/system for radiation sensing is configured to detect high and low LET radiation. The radiation sensing system may include a high LET detector and a low LET detector coupled to the high LET detector by a CPU, wherein the high LET detector and the low LET detector are assembled within a single unit. The device/system may also include a high LET and low LET detector that may be coupled together without an internal CPU. Overall, the device/system may be a stand-alone system and/or coupled to an external processing device. The device/system may also be approximately 6.times.6.times.2 cm.sup.3 in size, making it hand portable and may weigh less or equal to approximately ninety (90) grams, and operate on less than or approximately 0.25 watts of power.

Stassinopoulos, Epaminondas G. (Inventor)

2008-01-01

450

Automatic calorimetry system monitors RF power  

NASA Technical Reports Server (NTRS)

Calorimetry system monitors the average power dissipated in a high power RF transmitter. Sensors measure the change in temperature and the flow rate of the coolant, while a multiplier computes the power dissipated in the RF load.

Harness, B. W.; Heiberger, E. C.

1969-01-01

451

Multilevel converters for power system applications.  

National Technical Information Service (NTIS)

Multilevel converters are emerging as a new breed of power converter options for power system applications. These converters are most suitable for high voltage high power applications because they connect devices in series without the need for component m...

J. S. Lai J. P. Stovall F. Z. Peng

1995-01-01

452

Application of a battery energy storage system for power quality improvement of Jeju power system  

Microsoft Academic Search

The capacity of wind power generation in Jeju-island reaches more than 200 MW in the near future, which corresponds to more than 13% of power consumption of the island. This paper investigates performances of a battery energy storage system (BESS) to smooth power outputs of the wind farms for power quality enhancement of Jeju power system. Jeju power system including

Gyeong-Hun Kim; Hyeong-Heak Bae; Sang-Yong Kim; ChulSang Hwang; Hyo-Guen Lee; Namwon Kim; Hyo-Rong Seo; In-Keun Yu; Jung-Do Park; Dong-Young Yi; Sangjin Lee

2010-01-01

453

Electrical power generating system. [for windpowered generation  

NASA Technical Reports Server (NTRS)

An alternating current power generation system adopted to inject power in an already powered power line is discussed. The power generating system solves to adjustably coup an induction motor, as a generator, to an ac power line wherein the motor and power line are connected through a triac. The triac is regulated to normally turn on at a relatively late point in each half cycle of its operation, whereby at less than operating speed, and thus when the induction motor functions as a motor rather than as a generator, power consumption from the line is substantially reduced. The principal application will be for windmill powered generation.

Nola, F. J. (inventor)

1981-01-01

454

TPV Power Source Using Infrared-Sensitive Cells with Commercially Available Radiant Tube Burner  

NASA Astrophysics Data System (ADS)

Over the last several years, JX Crystals has invented and systematically developed the key components for thermophotovoltaic systems. These key components include GaSb infrared sensitive cells, high power density shingle circuits, dielectric filters, and hydrocarbon-fueled radiant tube burners. Most recently, we invented and demonstrated an antireflection (AR)-coated tungsten IR emitter which when integrated with the other key components should make TPV systems with efficiencies over 10% practical. However, the use of the AR tungsten emitter requires an oxygen-free hermetic seal enclosure. During a 2003 Small Business Innovative Research (SBIR) Phase I contract, we integrated a tungsten emitter foil and a commercial SiC radiant tube burner within an emitter thermos and successfully demonstrated its operation at high temperature. We also designed a complete stand alone 500 W TPV generator. During the upcoming SBIR Phase II, we plan to implement this design in hardware.

Fraas, Lewis; Minkin, Leonid; Hui, She; Avery, James; Howells, Christopher

2004-11-01

455

Power Block, an adaptable spacecraft power control system  

NASA Astrophysics Data System (ADS)

The authors discuss power block electric power subsystem, a modular, expandable spacecraft power system which can be used in a wide range of spacecraft applications without non-recurring engineering. They describe the power block controller (PBC), a modular, microprocessor-based solar array power/battery charge controller. The PBC controls battery charging current by diverting unwanted solar array current to ground with the use of switching shunts and provides an interface among spacecraft solar arrays, a telemetry and command system, batteries, and a power distribution unit (PDU). The PBC's hardware, software, interfaces, and capabilities are described. It is pointed out that one power block can provide battery charge balance for a spacecraft containing up to 4 batteries with 3600 W of solar array output power. System efficiency at 3600 W is 99 percent (exclusive of PDU operation).

Baker, William; Kenig, Alfredo; Streeter, Gary

456

High efficiency midrange wireless power transfer system  

Microsoft Academic Search

Wireless power transfer systems using near-field magnetic coupling are attractive as they allow power transfer with high efficiency and do not require an unobstructed path between transmitter and receiver. In this work a two coil wireless power transmission system is analyzed, including the driving amplifier, and a demonstration system is built and characterized. The system achieves 76% efficiency for a

Jaime Garnica; Joaquin Casanova; Jenshan Lin

2011-01-01

457

Application of Bifurcation Analysis to Power Systems  

Microsoft Academic Search

Electric power systems are physically some of the largest and most complex nonlinear systems in the world. Bifurcations are rather mundane phenomena in power systems. The pioneer work on the local bifurcation analysis of power systems can be dated back to the 1970s and earlier. Within the last 20 years or so nonlinear dynamical theory has become a subject of

Hsiao-Dong Chiang

458

Artificial Intelligence and Spacecraft Power Systems  

NASA Technical Reports Server (NTRS)

This talk will present the work which has been done at NASA Marshall Space Flight Center involving the use of Artificial Intelligence to control the power system in a spacecraft. The presentation will include a brief history of power system automation, and some basic definitions of the types of artificial intelligence which have been investigated at MSFC for power system automation. A video tape of one of our autonomous power systems using co-operating expert systems, and advanced hardware will be presented.

Dugel-Whitehead, Norma R.

1997-01-01

459

System and method for advanced power management  

DOEpatents

A power management system is provided that includes a power supply means comprising a plurality of power supply strings, a testing means operably connected to said plurality of power supply strings for evaluating performance characteristics of said plurality of power supply strings, and a control means for monitoring power requirements and comprising a switching means for controlling switching of said plurality of power supply strings to said testing means.

Atcitty, Stanley (Albuquerque, NM); Symons, Philip C. (Surprise, AZ); Butler, Paul C. (Albuquerque, NM); Corey, Garth P. (Albuquerque, NM)

2009-07-28

460

Electric power distribution and load transfer system  

SciTech Connect

This patent describes a power distribution system. It comprises at least two switch means for controlling the application of power from a power source to a power output; at least two current means for preventing reverse power flow through respective ones of switch means; and processing means for providing control signals to operate the switch means, effective to switch respective ones of the power sources between on and off states with respect to the power output.

Bradford, M.P.; Parkinson, G.W.; Grant, R.M.

1989-10-10

461

Power coupling alternatives for the NEP thermionic power system  

Microsoft Academic Search

Three output power coupling methods which can eliminate the high temperature insulator from the Nuclear Electric Propulsion (NEP) power system are described and estimates of their effects on the NEP system masses and cooling requirements are presented. Nominal 400 kWe power systems using push-pull and flux reset inductive output coupling are shown to have specific masses of 22.2 kg\\/kWe and

M. L. Manda; E. J. Britt; G. O. Fitzpatrick

1978-01-01

462

Design of a 240 MW e Solar Thermal Power Plant  

Microsoft Academic Search

In this paper, the general design philosophy for a large 240 MWe pure solar storage plant is discussed. The proposed stand alone plant design will use the same low cost Compact Linear Fresnel Reflector (CLFR) array system previously reported (Mills et al, 2003; Hu et al, 2003) and currently being constructed for a coal fired plant preheating project. In the

D. Mills; G. L. Morrison

463

Design and control of a low power DC-AC converter fed by a photovoltaic array  

Microsoft Academic Search

In this paper, we present a DC-AC converter fed by a PV array for stand alone applications up to 50 W. It is dedicated to rural areas in countries having abundant sunshine and where there is no grid connection to the utility network or the power supply is weak as in many underdeveloped countries. Using a single PV array of

F. Belkacem; D. Diallo; G. A. Capolino

2004-01-01

464

SOLERAS - Solar-Powered Water Desalination Project at Yanbu: PKI Collectors Performance.  

National Technical Information Service (NTIS)

The seawater desalination pilot plant at Yanbu in Saudi Arabia is a unique experiment in which an indirect bulk freeze desalination process is integrated with a stand-alone solar cogeneration power plant. Thermal energy is stored in molten salt and is con...

G. Hamad

1987-01-01

465

Operation experience of a solar- and wind-powered desalination demonstration plant  

Microsoft Academic Search

The present work outlines the designing, erection and operation process of a stand-alone desalination plant powered by both solar photovoltaic and wind energy. Such a plant will serve small isolated communities in remote areas devoid of water resources. A specially customized code was built to simulate the operation of the installation in order to allow appropriate choice of components specifications.

Dan Weiner; David Fisher; Eduard J. Moses; Baruch Katz; Giora Meron

2001-01-01

466

Autonomous power system intelligent diagnosis and control  

NASA Technical Reports Server (NTRS)

The Autonomous Power System (APS) project at NASA Lewis Research Center is designed to demonstrate the abilities of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution hardware. Knowledge-based software provides a robust method of control for highly complex space-based power systems that conventional methods do not allow. The project consists of three elements: the Autonomous Power Expert System (APEX) for fault diagnosis and control, the Autonomous Intelligent Power Scheduler (AIPS) to determine system configuration, and power hardware (Brassboard) to simulate a space based power system. The operation of the Autonomous Power System as a whole is described and the responsibilities of the three elements - APEX, AIPS, and Brassboard - are characterized. A discussion of the methodologies used in