11,594 research outputs found
Investigation of test methods, material properties and processes for solar cell encapsulants
The potentially useful encapsulating materials for Task 3 of the Low-Cost Silicon Solar Array project were studied to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. Materials for study were chosen on the basis of existing knowledge of generic chemical types having high resistance to environmental weathering. The materials varied from rubbers to thermoplastics and presented a broad range of mechanical properties and processing requirements. Basic physical and optical properties were measured on the polymers and were redetermined after exposure to indoor artificial accelerated aging conditions covering four time periods. Strengths and weaknesses of the various materials were revealed and data was accumulated for the development of predictive methodologies. To date, silicone rubbers, fluorocarbons, and acrylic polymers appear to have the most promising combination of characteristics. The fluorocarbons may be used only as films, however, because of their high cost
Investigation of test methods, material properties and processes for solar cell encapsulants
Low cost encapsulation materials for the Flat Plate Solar Array Program (FSA) are investigated. The goal of the program is to identify, test, evaluate and recommend encapsulation materials and processes for the fabrication of cost effective and long life solar modules. Accelerated aging techniques for module component lifetime studies, investigation of candidate outer cover films and continued evaluation of soil repellant coatings are also included
Investigation of test methods, material properties and processes for solar cell encapsulants
The goal of the program is to identify, test, evaluate and recommend encapsulation materials and processes for the fabrication of cost-effective and long life solar modules. Of the ) per square meter allocated for the encapsulation components approximately 50% of the cost ($9/sq m) may be taken by the load bearing component. Due to the proportionally high cost of this element, lower costing materials were investigated. Wood based products were found to be the lowest costing structural materials for module construction, however, they require protection from rainwater and humidity in order to acquire dimensional stability. The cost of a wood product based substrate must, therefore, include raw material costs plus the cost of additional processing to impart hygroscopic inertness. This protection is provided by a two step, or split process in which a flexible laminate containing the cell string is prepared, first in a vacuum process and then adhesively attached with a back cover film to the hardboard in a subsequent step
Investigation of Test Methods, Material Properties and Processes for Solar Cell Encapsulants
The evaluation of potentially useful low cost encapsulation materials is discussed. The goal is to identify, evaluate, test and recommend encapsulant materials and processes for the production of cost effective, long life solar cell modules. Technical investigations concerned the development of advanced cure chemistries for lamination type pottants; the continued evaluation of soil resistant surface treatment, and the results of an accelerated aging test program for the comparison of material stabilities. New compounds were evaluated for efficiency in curing both ethylene/vinyl acetate and ethylene/methyl acrylate pottants intended for vacuum bag lamination of solar cells. Two component aliphatic urethane casting syrups were evaluated for suitability as solar module pottants on the basis of optical, physical and fabrication characteristics
An inside-out origin for the eukaryotic cell.
Although the origin of the eukaryotic cell has long been recognized as the single most profound change in cellular organization during the evolution of life on earth, this transition remains poorly understood. Models have always assumed that the nucleus and endomembrane system evolved within the cytoplasm of a prokaryotic cell
The impact of fiscal policy on economic activity over the business cycle - evidence from a threshold VAR analysis
Does the state of the business cycle matter for the effects of fiscal policy shocks on GDP? This study analyses quarterly German data from 1976 to 2009 in a threshold SVAR, expanding the SVAR approach by Blanchard and Perotti (2002). In a linear benchmark SVAR, the analysis finds that hiking spending yields a short-term fiscal multiplier of around 0.70, while the fiscal multiplier resulting from an increase in taxes and social security contributions is -0.66. In addition, the threshold model derives fundamentally new insights on the effects of shocks, depending on when in the business cycle they occur, their size and their direction. Most importantly, fiscal spending multipliers are much larger in times of a negative output gap but have only a very limited effect in times of a positive output gap. Discretionary revenue policies, on the other hand, have a generally more limited impact. Our findings have important implications for the optimal fiscal policy mix over different stages of the business cycle. Various robustness checks, including a different threshold specification, do not influence these implications substantially. --fiscal policy,business cycle,nonlinear analysis,fiscal multipliers
Impact of a XENONnT Signal on LHC Dijet Searches
It is well-known that dark matter (DM) direct detection experiments and the
LHC are complementary, since they probe physical processes occurring at
different energy scales. And yet, there are aspects of this complementarity
which are still not fully understood, or exploited. For example, what is the
impact that the discovery of DM at XENONnT would have on present and future
searches for DM in LHC final states involving a pair of hadronic jets? In this
work we investigate the impact of a XENONnT signal on the interpretation of
current dijet searches at the LHC, and on the prospects for dijet signal
discovery at the High-Luminosity (HL) LHC in the framework of simplified
models. Specifically, we focus on a general class of simplified models where DM
can have spin 0, 1/2 or 1, and interacts with quarks through the exchange of a
scalar, pseudo-scalar, vector, or pseudo-vector mediator. We find that
exclusion limits on the mediator's mass and its coupling to quarks from dijet
searches at the LHC are significantly affected by a signal at XENONnT, and that
signal events at XENONnT would drastically narrow the region
in the parameter space of simplified models where a dijet signal can be
discovered at C.L. at the HL-LHC.Comment: 23 pages, 3 figures, 3 tables, version accepted by JHE
Investigation of test methods, material properties, and processes for solar cell encapsulants
The development of pottant compounds is emphasized. Formulation of the butyl acrylate syrup/casting pottant was completed. The formulation contains an ultraviolet stabilizer system and may be cured with an initiator that, unlike former selections, presents no shipping of handling hazards to the user. The catalyzed syrup is stable at room temperature and has a pot life of at least eight hours. The formulation of the ethylene/methyl acrylate lamination pottant was also completed. This compound is the alternative pottant to EVA and is similarly produced as an extruded sheet that is wound into rolls. This resin is inherently nonblocking
Encapsulation task of the low-cost silicon solar array project. Investigation of test methods, material properties, and processes for solar cell encapsulants
The results of an investigation of solar module encapsulation systems applicable to the Low-Cost Solar Array Project 1986 cost and performance goals are presented. Six basic construction elements were identified and their specific uses in module construction defined. A uniform coating basis was established for each element. The survey results were also useful in revealing price ranges for classes of materials and estimating the cost allocation for each element within the encapsulating cost goal. The six construction elements were considered to be substrates, superstrates, pottants, adhesives, outer covers and back covers
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