1,518 research outputs found
Novel duplex vapor-electrochemical method for silicon solar cells
Silicon obtained by the SiF4-Na reaction was analyzed by spark source mass spectrometry (SSMS). Silicon samples prepared from induction melted powder were evaluated for electrical properties using four point probe conductivity and thermoelectric methods. SiF4-Na reaction under P sub SiF4 greater than 1 atmosphere. The amount of silicon produced was increased from 25 g per batch (in the glass reactor) to greater than 70 g per batch in the stainless steel reactor. The study of the effects of reaction variables such as P sub SiF4 and maximum temperature attained on the particle size of silicon powder showed that the silicon particle size tends to grow larger with increasing pressure of the SiF4 gas in the reaction system
Novel duplex vapor-electrochemical method for silicon solar cells
Silicon was produced by alternate pulse feeding of the reactants SiF4 gas and liquid sodium. The average temperature in the reactor could be controlled, by regulating the amount of reactant in each pulse. Silicon tetrafluoride gas was analyzed by mass spectrometry to determine the nature and amount of contained volatile impurities which included silicon oxyfluorides, sulfur oxyfluorides, and sulfur dioxide. Sodium metal was analyzed by emission spectrography, and it was found to contain only calcium and copper as impurities
A Note on the Thermodynamics of the Wet-and Dry-Bulb Hygrometer
The paper deals with the thermodynamic study of the wet-and-dry bulb
hygrometer as applied to other liquids besides water. Hygroscopic liquids are also included.
The theory is found in reasonable accord with experiment
Barriers to Changing Dietary Behavior
Abstract
Dietary change requires giving up long established patterns of eating behavior and acquiring new habits. ‘Noncompliance’
to diet advice may be a result of inability to provide diet self-management training and getting the
right messages across to change eating behavior. Using a pre-tested questionnaire based interview, we carried out a
study amongst 350 adults (> 20 years) with type 2 diabetes from two metro cities in South India, who had previously
received diet advice with the objective to understand perceptions, attitudes and practices, as well as study factors
that enhance or reduce compliance to diet advice. Ninety six patients (28%) followed diet for the full duration of
diabetes (Group1), 131 (38%) followed diet for a partial duration varying between more than a quarter to three
quarters of the total diabetes duration (Group 2) and 115 (34%) did not follow diet advice (Group 3) – followed for
a duration less than a quarter of their diabetes duration.
Study results show that many factors both patient and health care provider related influence outcomes of dietary
advice. Factors that have a positive impact on compliance are – older age, shorter duration, nuclear family, good
family support, less busy work life, higher health consciousness, advice given by dietician, more frequent visits to
dietician, advice that includes elements to promote overall health not merely control of blood sugar, diet counseling
that is easy to understand and use and includes healthy food options, cooking methods, practical guidance to
deal with lifestyle issues. We conclude that patient barriers related to life circumstance are mostly non-modifiable,
most modifiable barriers are related to behavioural aspect and the inability of the health care provider to provide
individualized diet advice and self management training. Efforts must be made to improve counseling skills
Flexible copper-indium-diselenide films and devices for space applications
With the ever increasing demands on space power systems, it is imperative that low cost, lightweight, reliable photovoltaics be developed. One avenue of pursuit for future space power applications is the use of low cost, lightweight flexible PV cells and arrays. Most work in this area assumes the use of flexible amorphous silicon (a-Si), despite its inherent instability and low efficiencies. However, polycrystalline thin film PV such as copper-indium-diselenide (CIS) are inherently more stable and exhibit better performance than a-Si. Furthermore, preliminary data indicate that CIS also offers exciting properties with respect to space applications. However, CIS has only heretofore only produced on rigid substrates. The implications of flexible CIS upon present and future space power platforms was explored. Results indicate that space qualified CIS can dramatically reduce the cost of PV, and in most cases, can be substituted for silicon (Si) based on end-of-life (EOL) estimations. Furthermore, where cost is a prime consideration, CIS can become cost effective than gallium arsenide (GaAs) in some applications. Second, investigations into thin film deposition on flexible substrates were made, and data from these tests indicate that fabrication of flexible CIS devices is feasible. Finally, data is also presented on preliminary TCO/CdS/CuInSe2/Mo devices
Novel duplex vapor electrochemical method for silicon solar cells
Progress in the development of low-cost solar arrays is reported. Topics covered include: (1) development of a simplified feed system for the Na used in the Na-SiF4 reactor; (2) production of high purity silicon through the reduction of sodium fluosilicate with sodium metal; (3) the leaching process for recovering silicon from the reaction products of the SiF4-Na reaction; and (4) silicon separation by the melting of the reaction product
Titanyl (IV), Zirconyl (IV), Hafnyl (IV) and Uranyl (VI) Complexes of Terdentate Benzoyl Hydrazones
Titanyl(IV), zixconyl(!V), hafnyl(IV) and uranyl(Vl) oomplexes
of beniz\u27Dyl hydrazones derti.ved frnm benzoyl hymazdne
and sal1cyla1dehyde (BSH), o-hydro!XY acetopheilOllle (BAH),
o-hydroxy propi0tphenone (BPH) and 2-hydroxy-1-naphthaldehyde
(BNH) are desc·ribed. These complexes were characterised
on the basis oof elemental analyses, electrical conductance and
spectral (IR, UV and visible) data. The tiltany1\u27(!V) complexes
having ·the formula [TiL(OH) (H20) lzO appear ·to have a seven-
coordinat·e geometry, the zirconyl and hafnyl complexes,
[ML(OHh(H20) )4 (M = Zr or HO appear to possess tetrameric
structure in which each metal atom is e.ight-coordina:ted as in
the origin,aJl salt, MOCh.8H20 (M = Zr or Hf) ; whereas uranyl
comple·xes [UO:J.;(H20hh are dimeric having phenoxide brlidges,
•tiu/°\u27u•ti
as revealed by the \u27-o,, r:in:g v~br.ations in the IR
spectra at ca. 845 cm-1, wi.th each metal atom having an eightcoordinated
structure. In all these complexes the benzoyl hydrazones
act as di!ba:sic te1r.dentate (N, o-. o-> chelating agentJs
Gall Bladder And Common Bile Duct Stones – When Is Direct Cholangiography Indicated?
The medical records of 277 consecutive patients who underwent cholecystectomy for benign gall stone
disease, were reviewed to determine the incidence and cause of biliary tract obstructuion
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