Production status of GaAs/Ge solar cells and panels

GaAs/Ge solar cells with lot average efficiencies in excess of 18 percent were produced by MOCVD growth techniques. A description of the cell, its performance and the production facility are discussed. Production GaAs/Ge cells of this type were recently assembled into circuits and bonded to aluminum honeycomb panels to be used as the solar array for the British UOSAT-F program

Efficacy of a fungal fermented product as fishmeal replacement in the diet of Penaeus monodon Fabricius post-larvae

The efficacy of diets, formulated by inclusion of an Aspergillus niger fermented product (AFP) as fish meal substitute, for Penaeus monodon post-larvae was determined. AFP was derived by solid state fermentation (SSF) of a mixture of soybean flour, wheat flour, groundnut oil cake and sesame oil cake in the ratio of 4: 3: 2: 1 respectively for 96 h. The feeding trial was conducted in post-larvae stocked @10 animals in circular perspex tanks containing 40 l of water with five dietary treatments each with three replicates for 52 days. The diets containing graded levels of AFP substituting 0, 50, 150, 250 and 350 g kg-1 of fishmeal were fed to the post-larvae. Data on the growth performance and nutrient utilization efficiency were recorded from the feeding trials. Results showed that the post-larval shrimp fed diet containing 150 g kg-1 AFP exhibited significantly better (p<0.05) growth rate (14.79 mg d-1 post-larva-1), feed conversion ratio (1.62), protein efficiency ratio (1.64) and apparent protein utilization (25.39) than the other diets. The diet with 350 g kg-1 AFP showed the best apparent protein digestibility (87.74 %), apparent fat digestibility (97.95 %) and apparent dry matter digestibility coefficient (77.09 %) among the test diets. The results of the present study suggest that AFP can be used to improve the digestibility of nutrients and that partial replacement of fishmeal is possible in P. monodon post-larval diets under optimum rearing conditions

Development of an Indexing Media Filtration System for Long Duration Space Missions

The effective maintenance of air quality aboard spacecraft cabins will be vital to future human exploration missions. A key component will be the air cleaning filtration system which will need to remove a broad size range of particles derived from multiple biological and material sources. In addition, during surface missions any extraterrestrial planetary dust, including dust generated by near-by ISRU equipment, which is tracked into the habitat will also need to be managed by the filtration system inside the pressurized habitat compartments. An indexing media filter system is being developed to meet the demand for long-duration missions that will result in dramatic increases in filter service life and loading capacity, and will require minimal crew involvement. The filtration system consists of three stages: an inertial impactor stage, an indexing media stage, and a high-efficiency filter stage, packaged in a stacked modular cartridge configuration. Each stage will target a specific range of particle sizes that optimize the filtration and regeneration performance of the system. An 1/8th scale and full-scale prototype of the filter system have been fabricated and have been tested in the laboratory and reduced gravity environments that simulate conditions on spacecrafts, landers and habitats. Results from recent laboratory and reduce-gravity flight tests data will be presented. The features of the new filter system may also benefit other closed systems, such as submarines, and remote location terrestrial installations where servicing and replacement of filter units is not practical

Characterization of a Regenerable Impactor Filter for Spacecraft Cabin Applications

Regenerable filters will play an important role in human exploration beyond low-Earth orbit. Life Support Systems aboard crewed spacecrafts will have to operate reliably and with little maintenance over periods of more than a year, even multiple years. Air filters are a key component of spacecraft life support systems, but they often require frequent routine maintenance. Bacterial filters aboard the International Space Station require almost weekly cleaning of the pre-filter screen to remove large lint debris captured in the microgravity environment. The source of the airborne matter which is collected on the filter screen is typically from clothing fibers, biological matter (hair, skin, nails, etc.) and material wear. Clearly a need for low maintenance filters requiring little to no crew intervention will be vital to the success of the mission. An impactor filter is being developed and tested to address this need. This filter captures large particle matter through inertial separation and impaction methods on collection surfaces, which can be automatically cleaned after they become heavily loaded. The impactor filter can serve as a pre-filter to augment the life of higher efficiency filters that capture fine and ultrafine particles. A prototype of the filter is being tested at the Particulate Filtration Laboratory at NASA Glenn Research Center to determine performance characteristics, including particle cut size and overall efficiency. Model results are presented for the flow characteristics near the orifice plate through which the particle-laden flow is accelerated as well as around the collection bands

In Situ Solid Particle Generator

Particle seeding is a key diagnostic component of filter testing and flow imaging techniques. Typical particle generators rely on pressurized air or gas sources to propel the particles into the flow field. Other techniques involve liquid droplet atomizers. These conventional techniques have drawbacks that include challenging access to the flow field, flow and pressure disturbances to the investigated flow, and they are prohibitive in high-temperature, non-standard, extreme, and closed-system flow conditions and environments. In this concept, the particles are supplied directly within a flow environment. A particle sample cartridge containing the particles is positioned somewhere inside the flow field. The particles are ejected into the flow by mechanical brush/wiper feeding and sieving that takes place within the cartridge chamber. Some aspects of this concept are based on established material handling techniques, but they have not been used previously in the current configuration, in combination with flow seeding concepts, and in the current operational mode. Unlike other particle generation methods, this concept has control over the particle size range ejected, breaks up agglomerates, and is gravity-independent. This makes this device useful for testing in microgravity environments

Refinement of fertilizer recommendation based on Soil Test Crop Response technology for rice under System of Rice Intensification

A study on Soil Test Crop Response based Integrated Plant Nutrition System (STCR - IPNS) were conducted adopting an Inductive cum Targeted yield model in non-calcareous sandy loam soils of Lithic Haplusteptat Regional Research Station, Tamil Nadu Agricultural University, Paiyur, Tamil Nadu during Kharif 2013 in orderto develop fertilizer prescriptions equation (FPEs) through IPNS for the desired yield targets of rice under SRI technique. A ready reckoner of fertilizer doses at varying soil test value, for attaining 6 to 9 t ha-1 target grain yield of rice has been worked out. Using these equations a validation trial was conducted on Kharif 2014 at this station. The grain yield of rice ranged from 2.54 t ha-1 in absolute control to 8.65 t ha-1 in STCR-IPNS-9 t ha-1. The STCR-IPNS @ 8 t ha-1 was effective and economical as compare with any other treatments. The deviation recorded in the achievement of targets aimed was within the range of ± 10 per cent (90 – 110 %) proving the validity of the FPEs. The STCR treatments recorded relatively higher response ratio (RR) and benefit-cost ratio (BCR) over blanket and farmer's practice and STCR-IPNS treatments recorded relatively higher RR and BCR over STCR-NPK alone treatments. Post-harvest soil tests for NPK revealed that there was maintenance of soil fertility. The STCR-IPNS @ 8 t ha-1 was effective and economical as compare with any other treatments. Thus, the Inductive cum Targeted yield model used to develop fertilizer prescription equations provides a strong basis for soil fertility maintenance consistent with high productivity and efficient nutrient management for sustainable and enduring Agriculture