A5024720433- Photovoltaic System Optimization Techniques
- Silicon and Solar Cell Technologies
- Photovoltaic Systems and Sustainability
- solar cell performance optimization
- Thin-Film Transistor Technologies
- Electrical Fault Detection and Protection
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- Force Microscopy Techniques and Applications
- Solar Thermal and Photovoltaic Systems
- Silicon Nanostructures and Photoluminescence
- High voltage insulation and dielectric phenomena
- Electronic Packaging and Soldering Technologies
- Non-Destructive Testing Techniques
- Advanced Surface Polishing Techniques
- Nanowire Synthesis and Applications
- Advanced MEMS and NEMS Technologies
- Industrial Vision Systems and Defect Detection
- Electrostatic Discharge in Electronics
- Structural Analysis of Composite Materials
- Copper Interconnects and Reliability
- Diamond and Carbon-based Materials Research
- Surface Roughness and Optical Measurements
- Organic Food and Agriculture
National Renewable Energy Laboratory
2016-2025
University of Miami
2024
University of Alberta
2017
Dana-Farber Cancer Institute
2016
University of Michigan
2016
Sandia National Laboratories California
1997-2011
University of Colorado Boulder
2001-2010
Defense Advanced Research Projects Agency
2008-2010
National Grid (United States)
2010
University of Colorado System
2005-2006
1. Discharges of Purkinje cells and presumed mossy fibres were extracellularly recorded from vermal lobules VI VII two monkeys during saccadic eye movements fixation. Among the units showing changes in activity relation to either saccades or position, eighty‐four identified as ninety‐one cells. 2. Based on discharge patterns associated with saccades, fibre classified into long‐lead burst, burst‐tonic units. The burst (twenty‐eight units) started firing long before consisting a prelude...
ABSTRACT Photovoltaic (PV) modules operate at temperatures above ambient owing to the thermal energy of sunlight. The operating temperature primarily depends on temperature, incident sunlight, mounting configuration, packaging and wind speed. In this paper, cumulative degradation is modeled follow Arrhenius behavior. data are analyzed determine constant that would give average aging equivalent variable observed in field. These calculated for various locations using six configurations,...
Abstract Degradation from ultraviolet (UV) radiation has become prevalent in the front of solar cells due to introduction UV‐transmitting encapsulants photovoltaic (PV) module construction. Here, we examine UV‐induced degradation (UVID) various commercial, unencapsulated crystalline silicon cell technologies, including bifacial heterojunction (HJ), interdigitated back contact (IBC), passivated emitter and rear (PERC), totally diffused (PERT) cells. We performed UV exposure tests using...
The mechanical robustness of atomic layer deposited alumina and recently developed molecular aluminum alkoxide (“alucone”) films, as well laminated composite films composed both materials, was characterized using tensile tests along with a fluorescent tag to visualize channel cracks in the transparent films. All coatings were on polyethylene naphthalate substrates demonstrated similar evolution damage morphology according applied strain, including crack initiation, propagation at critical...
Abstract Previously undiscovered failure modes in photovoltaic (PV) modules continue to emerge field installations despite passing protocols for design qualification and quality assurance. Failure detect these prior widespread use could be attributed the limitations of present‐day standard accelerated stress tests (ASTs), which are primarily designed identify known degradation or at time development by applying simultaneous sequential factors (usually two most). Here, we introduce an testing...
Abstract Commercial backsheets based on polyvinylidene fluoride (PVDF) can experience premature field failures in the form of outer layer cracking. This work seeks to provide a better understanding changes material properties that lead crack formation and find appropriate accelerated tests replicate them. The PVDF-based backsheet have different structure composition, is often blended with poly(methyl methacrylate) (PMMA) polymer. We observed depletion PMMA upon aging sequential (MAST)...
Photovoltaic (PV) modules operate in an extreme environment and are exposed to radiation, humidity, hot cold thermal extremes. This paper focuses on polymeric-material degradation during PV-module operation at high ambient temperatures, solar irradiance low wind speed. The 2004 version of the IEC 61730 specification requires all polymeric materials used a photovoltaic module have Relative Thermal Index (RTI) or Endurance (RTE) least 20°C greater than maximum material temperature measured...
Discharges of Purkinje cells were recorded from the vermis, lobules VI and VII, a monkey trained to track visual target. When tracked sinusoidally oscillating target, cellular activity changes in phase with velocity signal eye movement. fixated stationary point, almost identical modulation occurred, reflecting motion retinal image The data suggest that vermis participates control smooth pursuit movements by providing oculomotor system actual target information which is sum signals.
The natural soiling of photovoltaic cover glass has recently been shown to include both an inorganic and organic particulate matter. Under favorable growth conditions, the latter can lead dense colonies filamentous fungi, which potentially leads measurable performance losses over time. Herein, we report on a field study where coupon samples were deployed in soiling-prone locations, focused Dubai (United Arab Emirates) Mumbai (India). For each site location, clear differences observed. from...
Sidegating in GaAs integrated circuits can be eliminated molecular beam epitaxially grown structure with the incorporation of a buffer layer at low substrate temperatures (200–300 °C). We have two films which were identical except one had low-temperature included film structure. The modulation-doped heterojunctions designed to produce high-mobility two-dimensional electron gas. electrical characteristics gas for samples. No deleterious effect on mobility or carrier density was observed...
Concentrating photovoltaic (CPV) technology has recently gained interest based on its scalability and expected low levelized cost of electricity. The reliability encapsulation materials used in CPV systems, however, is not well established. For example, the present qualification test for modules includes only real-time ultraviolet (UV) exposure, i.e., methods accelerated UV testing have yet been developed. To better define stress inherent to infrared spectra transmitted through...
Debonding of photovoltaic (PV) encapsulation in moist environments is frequently reported but presently not well understood or quantified. Temperature cycling, moisture, and mechanical loads often cause loss adhesion interfacial debonding, initially facilitating back-reflectance reduced electrical current, ultimately leading to internal corrosion module functionality. To investigate the effects temperature (T) relative humidity (RH) on kinetics we developed a mechanics-based technique...
Abstract Reduced optical transmittance of encapsulants resulting from ultraviolet (UV) degradation is frequently identified as a cause decreased performance through the service life photovoltaic modules. However, present module safety and qualification standards apply short UV doses, only capable examining design robustness “infant mortality” failures. Furthermore, essential information remains unknown that might be used to screen product lifetime. We conducted an interlaboratory study...
The accumulation of soiling on photovoltaic modules and the mirrors concentrating solar power systems causes non-negligible energy losses with economic consequences. These challenges can be mitigated, or even prevented, through appropriate actions if magnitude is known. Particle counting analysis a common procedure to characterize soiling, as it easily performed micrographs glass coupons devices that have been exposed environment. does not, however, yield invariant results across...