bluuebunny/crossref_metadata_2025_split huggingface dataset:
Event report: Sunrayce 93: Collegiate competition introduces American public to photovoltaics
Authors: Basore Paul A. 
Published: July 2007

AbstractThirty‐four university teams raced their solar‐powered cars from Texas to Minnesota during the week of the summer solstice, 20‐26 June 1993. the event, called Sunrayce 93, was a dazzling display of creativity and ingenuity by some of the brightest students in North America. Organized by the United States Department of Energy as an educational programme for college‐level science and engineering students, the race also serves to introduce the public to photovoltaics, electric vehicles and energy efficiency.
Considerations in the design of a one‐axis tracking photovoltaic system
Authors: Lorenzo E. , Macagnan M. H. 
Published: July 2007

AbstractWith the growing construction of large grid‐connected photovoltaic plants, the need to maximize energy collection and reduce costs is obvious. the use of tracking systems permits not only the maximization of energy collection but also a gain in the efficiency of DC to AC conversion. Nevertheless, when compared with stationary systems the literature points out some disadvantages, such as increased expense and more shadowing losses (or greater land area requirement). In this work we examine some alternatives regarding the electrical configuration of the panels for north‐south horizontal axis tracking. the choice of the best alternative produces similar results in terms of ground cover ratio, shadowing factor and costs when compared with stationary systems.
Optimum battery configuration for maximum utilization of photovoltaics
Authors: Casacca Margaret A. , Salameh Ziyad M. , Capobianco Maria R. , Losch Ross 
Published: July 2007

AbstractVarious photovoltaic (PV)‐powered battery storage configurations are analysed to determine if the percentage of available energy stored in the battery can be improved. Both deep‐cycle and shallow‐cycle lead‐acid batteries are considered. Computer simulation techniques are used to model the characteristics of the PV array, daily loads and environmental conditions. Three configurations were tested: one 60 ampere‐hour (Ah) battery, two 60 Ah batteries in parallel and two 60 Ah batteries that switch between the PV array and the load. Results show that the conventional PV‐powered configuration, where one battery is charged, wastes enormous amounts of energy by reaching a charged state while the PV array can still provide energy. A dual battery system enables the excess energy to be shunted into the battery under load while concurrently ensuring that one battery is constantly under charge until a full state of charge is achieved.
Silicon solar cells: The ultimate photovoltaic solution?
Authors: Green Martin A. 
Published: July 2007

AbstractIn the past, there has been a tendency to regard silicon cells as a stop‐gap ‘workhorse’, providing a photovoltaic presence in the market but with displacement by a more ideal technology being inevitable. Developments over the past decade encourage a re‐evaluation of this conception.This paper explores the proposition that, rather than being a stop‐gap, silicon has the potential to become the ultimate photovoltaic solution. Strengths relative to other emerging photovoltaic technologies are outlined, as are three alternative, and possibly complementary, routes for future evolution of the technology. the strengths lie in the presently established market position, the on‐going improvements to the technology and the remaining scope for future improvement and the sustainability of silicon‐based technology. the three possible routes for future evolution are the on‐going development of present bulk substrate approaches, the use of silicon cells in concentrators ranging from low‐concentration stationary systems to high‐concentration tracking systems, and thin‐film silicon technology.
Future use of silicon solar cells in extraterrestrial applications
Authors: Iles Peter A. 
Published: July 2007

AbstractThis paper discusses future extraterrestrial applications for which crystalline silicon solar cells can be used. Current operating requirements for cells in space are discussed, and the range of future space missions is reviewed to select those missions where silicon cells can be used successfully.The decision to use silicon cells will not be based on technical considerations alone. It is necessary also to consider other factors that will affect the decision, including detailed user requirements, proven performance for production cells and competition from other cell designs. We have indicated some areas of development that will help facilitate the use of silicon cells.
Microcharacterization of CdTe films deposited by close‐spaced sublimation
Authors: Matson R. J. , Hasoon F. S. , Jones K. M. , Al‐Jassim M. M. , Tomlinson R. D. 
Published: July 2007

AbstractMicrocharacterization of the luminescent, structural, electrical and topographical properties of thin films of close‐spaced sublimation (CSS)‐fabricated CdTe was performed. the film morphology was found to be dependent on the film thickness, deposition conditions and post‐deposition treatment. the complementary use of electron beam‐induced current (EBIC) and cathodoluminescence (CL) analysis in the scanning electron microscope demonstrated large inter‐ and intragrain inhomogeneities in the luminescent and electrical properties of the films. Follow‐on plan‐view examinations with the transmission electron microscope revealed varying densities of structural dejects, such as stacking faults and threading dislocations, which could explain the variations observed in the CL and EBIC images. Consisting primarily of experimental observations and comments, this report is phenomenological in nature.
Reduced temperature coefficients for recent high‐performance silicon solar cells
Authors: Zhao J. , Wang A. , Robinson S. J. , Green M. A. 
Published: July 2007

AbstractThe PERC cell (passivated emitter and rear cell) and PERL (passivated emitter and rear locally‐diffiused) cell have recently demonstrated improved cell performance owing to the high quality of surface passivation and high bulk carrier lifetimes. the effect of temperature on the performance of these cells is reported. As anticipated, owing to higher open‐circuit voltages these cells should have a lower temperature sensitivity of performance. the PERL cells demonstrated a normalized efficiency temperature variation of −2632 ppm °C−−1, which is the lowest ever reported for a silicon cell. However, PERC cells with a similarly high open‐circuit voltage showed a higher temperature sensitivity owing to the bulk resistance component, which limits the performance of PERC cells.
Photovoltaics as a demand‐side management technology: An analysis of peak‐shaving and direct load control options
Authors: Byrne John , Hegedus Steven , Wang Young‐Doo 
Published: July 2007

AbstractFor photovoltaic (PV) technology to play an increasing role in the utility sector at its present price, the technology needs to be developed in a manner that is consistent with, and takes advantage of, the economics of the demand‐side management (DSM) market. High‐value applications in this direction are for photovoltaics to perform a DSM function either as a direct load control (DLC) device or as a peak‐shaving option, which has the effect of raising the end‐use efficiency of customers' electrical equipment. This paper describes two PV‐DSM applications involving a water heater and an air conditioner studied at a residential PV test facility, Solar One House, located on the campus of the University of Delaware. A single 55‐W PV module directly connected to an electric water heater was found to offset standby and mixing losses, resulting in a 2°C increase in water temperature at the end of the afternoon compared to the standard DLC (grid‐disconnected) case. A conservatively sized PV array without storage could meet the house air‐conditioning load over 97% of the time from noon to 3 p.m., but only 69% from 3 p.m. to 6 p.m. If a PV system is combined with an air‐conditioning cycling program, success rates for supply of an air‐conditioning load are greatly increased, meeting almost 100% of the load between noon and 3 p.m. and 85% during 3 p.m. to 6 p.m. Furthermore, our results suggest that a modest‐size PV array with storage could significantly shave peak air‐conditioning loads during 3 p.m. to 6 p.m., thus reducing the peak demand faced by a utility. Preliminary analyses support the economic compatibility of a PV system as a DLC device or a peak‐shaving tool.
High‐eficiency silicon solar cells: Si/SiO2, interface parameters and their impact on device performance
Authors: Aberle A. G. , Glunz S. W. , Stephens A. W. , Green M. A. 
Published: July 2007

AbstractThis article presents the first measurements of the parameters of the Si/SiO2, interfaces employed on the record‐efficiency silicon solar cells made at the University of New South Wales (UNSW). the UNSW oxides are characterized by very low values of the surface state density (∼4 × 10−9cm−−2eV‐−−1), low values for the positive fixed oxide charge density (∼7 × 10−10cm−−2) and a pronounced asymmetry in the capture cross‐sections of electrons and holes. Using the microwave‐detected photoconductance decay method, we verify experimentally that these oxide parameters produce a strong dependence of the effective surface recombination velocity at oxidized p‐type silicon surfaces on the excess electron concentration within the wafer. In high‐performance silicon solar cells, this phenomenon produces a long‐wavelength spectral response that strongly depends on the bias light intensity, a characteristic ‘hump’ in the dark current‐voltage characteristics and fill factors that are lower than would be expected from the high open‐circuit voltages of 700 mV.
Accelerated publication 16.4% total‐area conversion efficiency thin‐film polycrystalline MgF2/ZnO/CdS/Cu(In,Ga)Se2/Mo solar cell
Authors: Contreras Miguel A. , Gabor Andrew M. , Tennant Andrew L. , Asher Sally , Tuttle John , Noufi Rommel 
Published: July 2007

AbstractThis communication reports an MgF2/ZnO/CdS/Cu(In,Ga)Se2/Mo/glass polycrystalline solar cell with a confirmed total‐area conversion efficiency of 16.4%. the thin‐film Cu(In,Ga)Se2absorber was fabricated by computer‐controlled physical vapor deposition (PVD) from the elemental sources. the resulting absorber has a Gal/In compositional grading that we refer to as a notch. Capacitance‐voltage (C‐V) measurements also reveal a graded doping profile in the region near the electronic p‐n junction. the enhanced device performance is characterized by an open‐circuit voltage (Voc) of 660 mV and a particularly high fill factor (FF) of 78.7%.
Solar photovoltaics in Sri Lanka: A short history
Authors: Gunaratne Lalith 
Published: July 2007

AbstractWith a significant unelectrified rural population, Sri Lanka has followed the evolution of solar photovoltaic (PV) technology in the West very closely since the 1970s as terrestrial applications for photovoltaics were developed. It was not until 1980 that the Sri Lankan government embarked on the promotion of solar photovoltaics for rural domestic use when the Ceylon Electricity Board formed the Energy Unit.Since then, solar photovoltaics has attracted the private sector, where several companies have been operating at different levels with varying degrees of success‐Vidya Silpa, agents for Arco and now Showa, selling solar photovoltaic systems on a small scale; Power & Sun (now S.P.&L. Co. Ltd) with its solar photovoltaic module assembling facility and a marketing operation; Sunpower Systems, agents for BP Solar Australia, focusing on institutional systems; and BP Solar Australia working on government‐funded projects‐so that private solar photovoltaic promoters have now gained valuable experience in a variety of dissemination methodologies.In addition, Australian and Sri Lankan government‐funded pilot projects such as the Pansiyagama 1000 home programme and the Uva Infrastructure Project with 74 large‐scale solar photovoltaic systems for rural hospitals and water pumping schemes‐ both administered by the National Housing Development Authority (NHDA) ‐have given all the local promoters further valuable insight into how and how not to promote solar photovoltaics.The establishment of community‐based solar photovoltaic programmes by non‐governmental organizations, such as the Sarvodaya Shramadana Society and the newly formed Solanka Associates, has developed a novel approach to bridge the gap between this state‐of‐the‐art technology and the remotely located end‐users.The developments in the Sri Lankan solar photovoltaic scene have attracted the attention of the World Bank. to quote from a paper presented by Loretta Schaeffer, Program Manager of the Bank's Asia Alternative Energy Unit in Washington at the Solar Energy Forum‐SOLTECH'93‐held on 28th April 1993 in Washington, DC: ‘The Bank may get involved in providing PV‐powered household systems throughout the country as there is a strong private sector involvement and use of proven local experience in systems design, development, installation, operation and maintenance’.Even though 70% of the 3.3 million homes are unelectrified, acceptance of solar photovoltaics as a viable alternative by policy makers is yet to be fully realized in Sri Lanka. the main obstacle has been the relatively high cost of photovoltaics. In spite of this, the private sector companies, certain government agencies (such as the NHDA) and the non‐government organizations view photovoltaics as a technology that could meet the basic needs for electricity of the rural people who, otherwise, would be left in the dark.
Studies of the micro‐ and nanostructure of polycrystalline CdTe and CuInSe2using atomic force and scanning tunneling microscopy
Authors: Moutinho H. R. , Hasoon F. S. , Kazmerski L. L. 
Published: July 2007

AbstractAtomic force microscopy (AFM) and scanning tunneling microscopy (STM) have been used to study the micro‐ and nanostructure of CdTe and CuInSe2thin films used for photovoltaic cells. Topographic images are comparable with those reported previously using conventional scanning electron microscopy (SEM)—to the limit of spatial resolution of the SEM technique. For higher magnifications, nanoscale structures and features have been observed for the first time with AFM and STM, and these observations have implications for the suitability and preparation of these semiconductors for high‐efficiency solar cell realization.
Accelerated publication 30.2% efficient GaInP/GaAs monolithic two‐terminal tandem concentrator cell
Authors: Friedman D. J. , Kurtz Sarah R. , Bertness K. A. , Kibbler A. E. , Kramer C. , Olson J. M. , King D. L. , Hansen B. R. , Snyder J. K. 
Published: July 2007

AbstractThe Ga0.5In0.5P/GaAs monolithic two‐terminal tandem cell has been adapted for concentrator operation. the adaptation involves changes in the grid design, top‐cell base thickness and top‐cell emitter thickness. the prototype concentrator device has demonstrated an efficiency exceeding 30% in the concentration range of 115‐260 suns, making this the first two‐terminal monolithic cell to exceed 30% efficiency.
New insights gained through pilot production of high‐eficiency silicon solar cells
Authors: Honsberg C. B. , Wenham S. R. 
Published: July 2007

AbstractExamination of results from the pilot production of buried‐contact solar cells (BCSC) allows several new insights into the effects of the substrate resistivity, the differences between upright and inverted pyramid texturing, the reflection after encapsulation and the doping level at which the emitter begins to dominate the overall recombination. A lower substrate resistivity in conjunction with thicker wafers reduces the effects of a high back surface recombination velocity and allows both higher voltages and efficiencies. In BCSCs with low substrate resistivities, the voltage is not limited by the back but by the emitter diffusion and the dislocation formation at the surface. Contrary to previous reports, best results have been realized with upright pyramids rather than inverted pyramids. In addition, the relative performance of the upright pyramids improves after encapsulation owing to the less than optimal unencapsulated reflection of these surfaces in the regions of the pyramid peaks where oxide layers are too thin to gain benefits as an antireflection layer. Recent results also indicate that the contributions to the dark saturation current from both the heavily phosphorus‐diffused region beneath the metal contact and the more lightly diffused top surface emitter are less than indicated previously. Finally, comparison between experimentally obtained voltages and those predicted through modelling with PC‐1D provides an estimate of the bulk material lifetimes in the pilot line cells.
Optical properties of intrinsic silicon at 300 K
Authors: Green Martin A. , Keevers Mark J. 
Published: July 2007

AbstractAn updated tabulation is presented of the optical properties of intrinsic silicon relevant to solar cell calculations. the absorption coeficient, refractive index and extinction coeficient at 300 K are tabulated over the 0.25‐1.45 μm wavelength range at 0.01 μm intervals.
17% Eficient thin‐film silicon solar cell by liquid‐phase epitaxy
Authors: Blakers A. W. , Weber K. J. , Stuckings M. F. , Armand S. , Matlakowski G. , Carr A. J. , Stocks M. J. , Cuevas A. , Brammer T. 
Published: July 2007

AbstractThin‐film silicon solar cells are promising candidates for meeting the requirements of high efficiency combined with low cost. We use liquid‐phase epitaxy to grow thin silicon films on highly doped substrates. A solar cell made on this material has been measured independently to have an efficiency of 17.0%. an important step in obtaining these high cell efficiencies is the removal of most of the heavily doped substrate on which the epitaxial layer is grown.
Estimation of the effects of an intensive solar intervention in the historical centre of jaén (Spain)
Authors: Almonacid G. , Nofuentes G. , Aguilar J. D. , De Casa J. La , Garrido A. 
Published: July 2007

AbstractThis paper is directed at evaluating the theoretical potential of an intensive solar intervention in the historical centre of the city of Jaén (Spain). Using the outputs of a solar intervention proposal comprising biomass, photovoltaics and solar thermal domestic hot water (DHW) over a 50‐building sample (in which those suitable for solar measures have been selected by evaluating each one over a collection of parameters), energy savings, environmental benefits and economic aspects of the envisaged actions are extrapolated over the entire historical centre. A saving of about 70% of conventional source energy annual consumption and a decrease of some 70% and 73% of CO2 and SOx annual releases, respectively, could be reached with respect to the present situation. Besides, an amount of conventionally generated electricity equivalent to the yearly photovoltaic‐generated electricity would require 131500 m3 of water a year, which is a rather significant feature for a dry climate like that of the city. the unitary cost of energy in the new scenario would be 60.7 pta kWh‐1 for photovoltaics, 329.9 pta m‐3 for DHW using solar thermal installations and 4.6 Pta kWh‐1 for biomass heating (1 US$ = 132.7 pta; 1 ECU = 160.9 pta).
Accelerated publication 17.1% efficient Cu(In,Ga)Se2‐based thin‐film solar cell
Authors: Tuttle J. R. , Contreras M. A. , Gillespie T. J. , Ramanathan K. R. , Tennant A. L. , Keane J. , Gabor A. M. , Noufi R. 
Published: July 2007

AbstractWe report a world‐record, total‐area efficiency of 17.1% for a polycrystalline thin‐film Cu(In,Ga)Se2‐based photovoltaic solar cell. the incorporation of Ga to raise the absorber bandgap has been accomplished successfully and in such a manner that an open‐circuit voltage of 654 mV and a fill factor of greater than 77% have been achieved. We describe briefly the deposition process, the device structure, and the device performance characteristics.
Anti‐herpes simplex virus activities ofEugenia caryophyllus(Spreng.) Bullock & S. G. Harrison and essential oil, eugenol
Authors: Tragoolpua Y. , Jatisatienr A. 
Published: July 2007

AbstractIn this study, an extract from the flower buds ofEugenia caryophyllus(Spreng.) Bullock & S. G. Harrison and the essential oil, eugenol, were evaluated for their anti‐herpes simplex virus properties on standard HSV‐1(F), standard HSV‐2(G) and ten HSV isolates. The plaque reduction assay showed that HSV‐1(F), HSV‐2(G), two HSV‐1 isolates (2, 30) and four HSV‐2 isolates (1, 2, 3, 21) were inhibited byE. caryophyllus. Only HSV‐1 isolates 1 and 30 were inhibited by eugenol. Thus, strains or isolates of viruses may affect the range of inhibition. Moreover, particles of HSV standard strains were directly inactivated byE. caryophyllusand eugenol. The total virus yield of HSV standard strains and isolates at 30 h also declined after treatment withE. caryophyllusand eugenol. TheE. caryophyllusextract exerted higher antiviral replication on HSV‐2(G) than on HSV‐1(F). The inhibition of the viral yield of HSV‐1 isolates was higher than standard HSV‐1(F) and standard HSV‐2(G) was also inhibited more than most of the HSV‐2 isolates. The anti‐HSV activity of eugenol against HSV‐1(F) and HSV isolates was stronger than with theE. caryophylluscrude extract. However, the percentage inhibition was more pronounced on HSV‐1(F) than on HSV‐2(G). Moreover, HSV‐1(1) and HSV‐2(1, 32) could not replicate when eugenol was included in the assay. Copyright © 2007 John Wiley & Sons, Ltd.
Simulations of the consequences of tongue surgery on tongue mobility: implications for speech production in post‐surgery conditions
Authors: Buchaillard Stéphanie , Brix Muriel , Perrier Pascal , Payan Yohan 
Published: July 2007

AbstractBackgroundWe studied the ability of a three‐dimensional (3D) biomechanical model of the oral cavity to predict the consequences of tongue surgery on tongue movements, according to the size and location of the tissue loss and the nature of the flap used by the surgeon.MethodThe core of our model consists of a 3D biomechanical model representing the tongue as a finite element structure with hexahedral elements and hyperelastic properties, in which muscles are represented by specific subsets of elements. This model is inserted in the oral cavity including jaw, palate and pharyngeal walls. Hemiglossectomy and large resection of the mouth floor are simulated by removing the elements corresponding to the tissue losses. Three kinds of reconstruction are modelled, assuming flaps with low, medium or high stiffness.ResultsThe consequences of these different surgical treatments during the activation of some of the main tongue muscles are shown. Differences in global 3D tongue shape and in velocity patterns are evaluated and interpreted in terms of their potential impact on speech articulation. These simulations have been shown to be efficient in accounting for some of the clinically observed consequences of tongue surgery.ConclusionFurther improvements still need to be done before being able to generate patient‐specific models easily and to decrease the computation time significantly. However, this approach should represent a significant improvement in planning tongue surgery systems and should be a very useful means of improving the understanding of muscle behaviour after partial resection. Copyright © 2007 John Wiley & Sons, Ltd.