Soybeans are an important crop for global food security. Every year, soybean yields are reduced by numerous soybean diseases, particularly the soybean cyst nematode (SCN). It is difficult to visually identify the presence of SCN in the field, let alone its population densities or numbers, as there are no obvious aboveground disease symptoms. The only definitive way to assess SCN population densities is to directly extract the SCN cysts from soil and then extract the eggs from cysts and count ...
The effects of the workplace on the safety, health, and productivity of personnel can be seen at various levels. To protect and boost general worker health, innovative hardware and software tools have been developed for the detection, elimination, substitution, and regulation of occupational hazards. Wearable technologies make it possible for constant tracking of workers and their environment, whereas connected worker solutions provide contextual information and support for decision-making. H...
Abstract Construction and use of electric cars have increased dramatically in recent years. It's totally silent, productive, wasteful to a minimum, and needs zero care. Although electric vehicles might help cut down on carbon dioxide emissions, the charging stations required to keep their batteries at an adequate level would put a significant strain on the country's electrical grid. Renewable energy sources, such as solar power, have the potential to lessen the burden on the power system. Ass...
A study was carded out with the goal of obtaining high open circuit voltages (Voc) in a-Si:H n-i-p solar cells, taking into account the evolutionary nature of the microstructure of the p-layers during growth. It is found that cells with players in the protocrystalline Si:H growth regime give the highest values of Voc not those with microcrystalline Si:H p-layers. Evidence for this conclusion is presented whereby Voc is related directly to the microstructure of the p-layers, as characterized u...
In studies of hydrogenated amorphous silicon (a-Si:H) n–i–p solar cells fabricated by rf plasma-enhanced chemical vapor deposition (PECVD), we have found that the maximum open circuit voltage (Voc) is obtained by incorporating p-type doped Si:H layers that are protocrystalline in nature. Specifically, these optimum p layers are prepared by PECVD in the a-Si:H growth regime using the maximum hydrogen-to-silane flow ratio possible without crossing the thickness-dependent transition into the...
For the first time direct correlations are obtained between the light induced changes under 1 sun illumination in the properties of a-Si:H and those in the characteristics of p-i-n cells incorporating identically-prepared i-layers. These correlations were obtained after account was taken of the effects that the location of the electron and hole quasi-Fermi levels have on the carrier recombination that occurs through the different gap states. The changes in midgap state density, as measured on...
As both population and energy use per capita increase, modern society is approaching physical limits to its continued fossil fuel consumption. The immediate limits are set by the planet’s ability to adapt to a changing atmospheric chemical composition, not the availability of resources. In order for a future society to be sustainable while operating at or above our current standard of living a shift away from carbon based energy sources must occur. An overview of the current state of active...
Forward bias current–voltage characteristics (JD–V) were studied for both p–i–n (superstrate) and n–i–p (substrate) (a-SiC:H p)/(a-Si:H i) solar-cell structures having different p/i interface layers and different thickness i-layers. Contributions of the p/i interfaces to the JD–V characteristics were separated, and the dependence on the thickness of the i-layers was established. Equivalence was observed in a comparison of the characteristics of p–i–n and n–i–p cells....
To take into account the presence of multiple light-induced defect states in hydrogenated amorphous silicon (a-Si:H) the evolution of the entire spectra of photoconductive subgap absorption, α(hν), has been analyzed. Using this approach two distinctly different light-induced defect states centered around 1.0 and 1.2 eV from the conduction band edge are clearly identified. Results are presented on their evolution and respective effects on carrier recombination that clearly point to the impor...
As regional shortages of fresh water become more prevalent, solar distillation using a single-effect basin holds promise as a method to bring low-cost, clean, and ecologically-responsible water to remote area dwellers. Compound parabolic concentrators (CPCs) can be used to direct more light onto the still increasing the throughput and efficiency of these passive solar devices. A computer program has been developed that uses the properties of materials and the solar energy characteristics of t...
Resources Conservation and Recycling, Jan 1, 2007 The recent development of Google Earth, an information service that provides imagery and three dimensional data depicting the entire Earth, provides an opportunity to use a new method of navigating information to save energy in the real world. Google Earth uses Keyhole Markup Language (KML) for modeling and storing geographic features and information for display in the Google Earth Client. This paper will analyze the potential of this novel an...
This paper quantifies the increased green house gas emissions and negative effect on energy conservation (or “efficiency penalty”) due to electric rate structures that employ an unavoidable customer charge. First the extent of customer charges was determined from a nationwide survey of U.S. electric tariffs. To eliminate the customer charge nationally while maintaining a fixed sum for electric companies for a given amount of electricity, an increase of 7.12% in the residential electrical ...
As the debate over the future of energy grows, often nuclear energy production is pitted against solar photovoltaic energy conversion. There is a widespread belief that solar cannot compete with nuclear energy economically without government subsidies. The continued and widespread belief in the economic viability of nuclear energy, however, is predicated in part on government-mandated limitation on the liability of the nuclear industry. To demonstrate the magnitude of this nuclear energy insu...
This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The pap...
The high cost of what have historically been sophisticated research-related sensors and tools has limited their adoption to a relatively small group of well-funded researchers. This paper provides a methodology for applying an open-source approach to design and development of a colorimeter. A 3-D printable, open-source colorimeter utilizing only open-source hardware and software solutions and readily available discrete components is discussed and its performance compared to a commercial porta...