NOPR Collection:

Preparation of cesium ferrite from the thermolysis of cesium tris(maleato) ferrate(III) hexahydrate

2016-07-20T06:07:51Z

Title: Preparation of cesium ferrite from the thermolysis of cesium tris(maleato) ferrate(III) hexahydrate Authors: Randhawa, B S; Sweety, Kamaljeet Abstract: The thermolysis of cesium tris(maleato) ferrate(III) hexahydrate, Cs₃ [Fe(C₂H₂C₂O₄)₃].6H₂O has been investigated up to 700^oC in static air atmosphere employing Mossbauer and thermo-analytical techniques(TG,DTA,DTG). The anhydrous complex undergoes reduction to iron(II) species at 185^oC followed by demixing of the cations forming α -Fe₂O₃ , and cesium oxalate/carbonate in successive stages. Finally, a solid state reaction occurs between α-Fe₂O₃ and cesium carbonate resulting in the formation of fine particles of cesium ferrite. The results have been compared with those of cesium ferrioxalate. Page(s): 25-28

Boron-lined neutron detectors with gamma discrimination for reactor applications

2016-07-20T06:06:56Z

Title: Boron-lined neutron detectors with gamma discrimination for reactor applications Authors: Prasad, K R; Dighe, P M; Alex, Mary Abstract: Neutron sensitive detectors capable of discriminating against gamma background have been indigenously developed for reactor applications. A boron-10 lined proportional counter with 3.5 cps/nv counting sensitivity and a boron-10 lined gamma compensated neutron ion chamber with a current sensitivity of 11 fA/nv have been developed for the reactor start up and intermediate range instrumentation, respectively. The detectors have all welded high-purity aluminium construction and integral mineral-insulated cable assembly. Explosion-welded SS-aluminium clad material has been used as interface between the aluminium body of the detector and the ceramic-metal in sulators. The counter has gas filling of argon and carbon dioxide at 20 cm Hg. It has 190 mg of enriched boron-10 coating and can be used over a neutron flux range of 0.1 nv to 10⁵ nv. The gamma compensated ion chamber has hydrogen filling at 10 psi pressure. Performance tests in typical neutron and gamma fields show that the chambers can tolerate gamma background up to 1000 r/h and over 100°C of ambient temperature. Page(s): 21-24

Fabrication of wide bandwidth miniature underwater acoustic transducers and study of their electro-acoustic performance*

2016-07-20T06:05:57Z

Title: Fabrication of wide bandwidth miniature underwater acoustic transducers and study of their electro-acoustic performance* Authors: Jain, S K; Gupta, Reeta; Lamba, G S Abstract: Miniature source transducers having high acoustic output response in the vicinity of 200-300 kHz have been designed and fabricated. The developed transducers, having wide bandwidth and large beamwidth, may be utilized as source transducers in underwater acoustic modeling studies. Design considerations and construction details of the developed transducers are described. Electro-acoustic performance of these transducers is also reported. The fabricated transducers show higher bandwidths and hence improved spiked signal signatures as compared to those shown by some of the imported transducers being used for modeling studies at present. Page(s): 16-20

Visco-elastic boundary layer flow past a stretching plate with suction and heat transfer with variable conductivity

2016-07-20T04:19:07Z

Title: Visco-elastic boundary layer flow past a stretching plate with suction and heat transfer with variable conductivity Authors: Ahmad, Naseem; Marwah, Kavita Abstract: Flow of Walters Liquid B model has been considered in the presence of uniform suction on the surface of the stretching plate. In the similarity solution, an unknown r has been introduced and its value is obtained by Newton-Raphson method for various values of suction parameter and visco-elasticity. These values of r have been used to predict the variation of temperature distribution with respect to suction and visco-elasticity, graphically. Page(s): 54-56