Analytical techniques and instrumentation: A compilation

Technical information on developments in instrumentation is arranged into four sections: (1) instrumentation for analysis; (2) analysis of matter; (3) analysis of electrical and mechanical phenomena; and (4) structural analysis. Patent information for two of the instruments described is presented

Incorporation of tritiated cytidine into ribonucleic acid by isolated pea nuclei

A new method for the isolation of the nuclei from plant tissue has been devised. This method consists in passing the plant tissue through a set of spring-loaded, counter-rotating rollers and collecting the liberated nuclei in sucrose solution containing calcium ions. A semi-automatic machine which couples the rollers with a special tissue chopping device has been constructed. It has been shown that nuclei obtained in this way actively incorporate cytidine-H3 into RNA. This incorporation is increased in the presence of nucleoside triphosphates and an energy-regenerating system

Silicon materials task of the low cost solar array project, part 2

Purity requirements for solar cell grade silicon material was developed and defined by evaluating the effects of specific impurities and impurity levels on the performance of silicon solar cells. Also, data was generated forming the basis for cost-tradeoff analyses of silicon solar cell material. Growth, evaluation, solar cell fabrication and testing was completed for the baseline boron-doped Czochralski material. Measurements indicate Cn and Mn seriously degrade cell performance, while neither Ni nor Cu produce any serious reduction in cell efficiency

Electrochemical control of iodine disinfectant for space transportation system and space station potable water

An electrochemical microbial check valve method (EC-MCV) for controlling the iodine disinfectant in potable water (PW) for NASA's space operations was proposed. The factors affecting the design and performance of the unit were analyzed. This showed that it would be feasible to construct a recyclable unit in a small volume that will operate in either an iodine removal or addition mode. The EC-MCV should remove active iodine species rapidly from PW, but the rapid delivery rates at end-use may make complete removal of excess I(-) difficult under some conditions. Its performace change with AgI buildup needs to be investigated, as this controls the time for recycling the unit. The EC-MCV has advantages over the passive microbial check valve (MCV) method currently in use, as it would allow precise control of the I2 level and would not introduce excess I(-) to the water. The presence of oxygen in the EC-MCV needs to be investigated as it could affect the efficiency of I2 addition and excess I(-) removal

Studies on the Gallium-iodine and Scandium-iodine Systems

The mass transfer from a hot zone to a cooler zone by means of a gaseous carrier has been observed to take place for many metals and compounds. Lee (19) studied the transport of many metals by their chloride and dissimilar gaseous chlorides. The subhalides, which form at higher temperatures on cooling disproportionate to metal and normal halide. This technique has been applied to purify many metals and compounds for which a sublimation or distillation method is not -practical due to the very high temperatures required. Aluminum has been purified using aluminum trichloride as a carrier (29). Pizzarello (25) has studied the epitaxial growth of GaAs in a system containing hydrogen and iodine gases (see more in text)

Natural dye sensitizer in dye sensitized solar cell

Blue-pea flower, turmeric, mulberries, brown rice, purple cabbage and Indian mulberry leave were successfully form on TiO2 mesoporous film using immersion method to produce TiO2 mesoporous photoanode for natural dye sensitized solar cells (DSSCs) assembly. The TiO2 mesoporous films were formed after calcinations at 450˚C for 30 min. The photoanodes were dipped in different types of natural dye for 24, 72 and 120 h. The properties of natural dye were investigated by ultraviolet-visible spectroscopy (UV-vis) and Fourier transform infrared spectroscopy (FTIR). From UV-Vis spectroscopy analysis, the wavelength range of the natural dye studied in this research lays between 350 and 800 nm. The FTIR result of the natural dye shows the present of intermolecular H-bond, C=O stretching vibration, C-O-C stretching vibration, C=C bending and C-H bending which was due to the component of anthocyanin, carotenoids and chlorophyll. The characterization including field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX) and x-ray diffraction (XRD) were carried out on the TiO2 mesoporous film. On the other hand, the conductivity of electrolyte for liquid electrolyte, gel electrolyte and solid electrolyte were also investigated. Gel electrolyte has the highest conductivity, 26.1 mS/cm while liquid electrolyte and solid electrolyte obtained 17.34 and 0.45 mS/cm, respectively. Finally, solar cells were prepared by sandwiching the TiO2 mesoporous photoanode with Platinum (Pt) counter electrode. The results showed short circuit current, open circuit current voltage, fill factor and efficiency for all samples during the present of light. The highest efficiency was obtained from Blue-pea sample that immersed for 120 h with 0.123% efficiency

Water system virus detection

A monitoring system developed to test the capability of a water recovery system to reject the passage of viruses into the recovered water is described. A nonpathogenic marker virus, bacteriophage F2, is fed into the process stream before the recovery unit and the reclaimed water is assayed for its presence. Detection of the marker virus consists of two major components, concentration and isolation of the marker virus, and detection of the marker virus. The concentration system involves adsorption of virus to cellulose acetate filters in the presence of trivalent cations and low pH with subsequent desorption of the virus using volumes of high pH buffer. The detection of the virus is performed by a passive immune agglutination test utilizing specially prepared polystyrene particles. An engineering preliminary design was performed as a parallel effort to the laboratory development of the marker virus test system. Engineering schematics and drawings of a fully functional laboratory prototype capable of zero-G operation are presented. The instrument consists of reagent pump/metering system, reagent storage containers, a filter concentrator, an incubation/detector system, and an electronic readout and control system

Studies of the use of high-temperature nuclear heat from an HTGR for hydrogen production

The results of a study which surveyed various methods of hydrogen production using nuclear and fossil energy are presented. A description of these methods is provided, and efficiencies are calculated for each case. The process designs of systems that utilize the heat from a general atomic high temperature gas cooled reactor with a steam methane reformer and feed the reformer with substitute natural gas manufactured from coal, using reforming temperatures, are presented. The capital costs for these systems and the resultant hydrogen production price for these cases are discussed along with a research and development program

Optimisation of Thin Film Copper Iodide as a p-type Transparent Thermoelectric Material

Alternative energy sources are being explored to reduce on fossil fuels and pollutant emissions. Green energy sources such as thermoelectric materials converters require little maintenance. Life-time testing has shown the capability of thermoelectric devices to exceed 100,000 h of steady-state operation. On the other hand, they are used for applications with high energetic relevance that include temperature control of scientific instruments to household air-cooling systems. The current trend for development of transparent, flexible and large area electronics, creates other challenges in terms of applications and development of thermoelectric materials. Some of the transparent oxide materials and conductors of n-type present adequate properties for application in thermoelectric devices. In the case of cooling processes, these need n-type and p-type elements. For the current scarcity of existing p-type elements, copper iodide is one of those which better fulfills all requirements: transparent and p-type electrical conductive, an abundant and environment friendly material. In this dissertation, CuI thin films (ca. 100-300nm) were produced through methods of copper iodination via vapour or solid, and deposited via resistive thermal evaporation of copper iodide, obtaining the γ-CuI phase in all cases. The thickness of Cu films was varied and the influence of iodination times studied, in vapour and solid methods. In samples prepared via thermal evaporation, a thorough analysis of the thickness effect on electrical properties was studied. The obtained results have shown to be possible to obtain films with transmittances over 75% in the range of visible light, with a band gap of 3.05 eV, Seebeck values above 200 μV/K, electrical conductivity above 500 Ω-1m-1, holes mobility of around 3x1019 cm-3 in films with 400 nm thicknesses obtained via solid and vapour iodination. Besides this study, different geometries of thermoelectric modules formed by films of CuI and AZO were also tested and so demonstrating the potential of copper iodide as a transparent p-type semiconductor in thermoelectric devices