Experimental and Theoretical Investigation of Powder–Binder Mixing Mechanism for Metal Injection Molding

Metallic powder and binder mixing mechanism plays a vital role in the quality of molded parts in metal injection molding. The present study is intended for experimental and theoretical investigation of powder–binder mixing mechanism to investigate the functional correlation among mixing parameters and performance characteristics for different composition of feedstocks. Powder loading and shear rate are considered as input parameter. Fuzzy expert system is adopted to test the validity of the experimental results by analyzing different numerical error criteria using the viscosity as output with respect to input parameters. The mean relative error and correlation coefficient for type A and type B were found to be 6.09% and 8.51% (<10%) and 0.990 and 0.998, respectively. Hence the result indicates a reliable acceptability of the proposed amount of powder loading for feedstock preparation.     

Comparative assessment of the efficiency of Fe-doped TiO2 prepared by two doping methods and photocatalytic degradation of phenol in domestic water suspensions

Fe-doped TiO₂ particles responding to visible light were synthesized by impregnation and calcination method using TiO₂ particle and Ti element, respectively. The optical and the chemical properties were characterized by measuring the X-ray diffraction (XRD) and UV–visible spectroscopy. The onset of absorption shifted to longer wavelengths on doping TiO₂ by the calcination process, which showed a better response as compared to the impregnation method. The photocatalytic reactivity was evaluated by the degradation of phenol with impregnated Fe-doped (0.5% w/w in Fe) and calcined Fe-doped (Fe_xTi_{1 x}O₂, x ¼ 0.005 (Fe/Ti molar ratio)) TiO₂ separately in distilled and tap water. The characterization results have confirmed the advanced possibility of correlation between photoactivity and the special property of sulfur-containing calcined Fe-doped TiO₂. In case of the coagulation of the undoped A-I and the Fe-doped B-I, the photoactivity showed a decrease due to the presence of natural electrolytes and due to the high pH of tap water, whereas in the case of the coagulation of calcined Fe-doped TiO₂ prepared from sulfides (Fe_xTiS₂), the photoactivity showed an increase. In this study, highest catalytic activity was found to be strongly dependent both on catalyst structure and on the type of water used.     

A low cost collector-cum-storage type solar water heater

A low cost collector-cum-storage type solar water heater has been developed. The cost of the heater is reduced by replacing window glass cover with 0.2 mm thick PVC film to avoid glass breakage in transportation and maintenance. In this paper the performances of solar water heaters having double glazing of PVC and glass have been compared. It was found that their performances are similar. Moreover, by providing an insulating cover in the night, the water remains warm till next morning for taking a bath etc. in the early hours when there is no sunshine.     

The filling of via-holes by a sputtered AlSi alloy and the development of a two-level metallisation structure

Filling via-holes with metal films is one of the most important processes for the development of a multi-level metallisation system. By employing rf bias sputtering, vias of different feature sizes were filled with AlSi films. The process of via-hole filling and the effect of substrate voltage is described. The surface topography and cross section of the filled via-holes are shown. A two-level metal interconnection structure using sputtered AlSi was fabricated. The structure was characterised for the intra-level and inter-level shorts and the continuity of via chains. The process is described and the results are presented.     

Studies on gap spacing between absorber and cover glazing in flat plate solar collectors

The air gap between absorber and cover glazing in fiat plate collectors has been optimized experimentally by designing three identical collector-cum-storage type solar water heaters with 25, 50 and 150 mm air gaps. The heater with 50 mm air gap collects 11.64% and 7.72% more energy compared with heaters having 25 mm and 150 mm air gaps, respectively. The average overall efficiencies of the heaters are 52.5%, 57.8% and 54.1% having 25, 50 and 150 mm air gaps. A 50 mm air gap has, therefore, been found to be optimum.     

Performance and testing of an improved solar water heater cum steam cooker

The paper reports performance and testing of an improved solar water heater cum steam cooker. The efficiency of the system as a solar water heater is 51.5 per cent and as a solar steam cooker is 16.1 per cent.     

On the fabrication of thin film MICs from substrate cleaning to pattern delineation

The processing technology for fabricating thin film MICs is discussed. All the process steps starting from the ceramic substrate cleaning, the substrate metallization with NiCr-Cu-Au sputtered layers, photolithography and the chemical etching are described. The practical problems, important precautions and the optimized processing parameters for the development of reproducible MICs is presented.     

Allowed and forbidden transition parameters for Fe XV

A comprehensive set of fine structure energy levels, oscillator strengths (f), line strengths (S), and radiative decay rates (A) for bound-bound transitions in Fe XV is presented. The allowed electric dipole (E1) transitions were obtained from the relativistic Breit-Pauli R-matrix method which is based on the close coupling approximation. A total of 507 fine structure energy levels with n ? 10, l ? 9, and 0 ? J ? 10 are found. They agree within 1% with the available observed energies. These energy levels yield a total of 27,812 E1, same-spin multiplets and intercombination transitions. The A values are in good agreement with those compiled by NIST and other existing values for most transitions. Forbidden transitions are obtained from a set of 20 configurations with orbitals ranging from 1s to 5f using the relativistic code SUPERSTRUCTURE (SS) in the Breit-Pauli approximation. From a set of 123 fine structure levels, a total of 6962 S and A values are presented for forbidden electric quadrupole (E2), electric octupole (E3), magnetic dipole (M1), and magnetic quadrupole (M2) transitions. The energies from SS calculations agree with observed energies to within 1-3%. A values for E2, M1 transitions agree very well with the available values for most transitions while those for M2 transitions show variable agreement. The large set of transition parameters presented should be applicable for both diagnostics and spectral modeling in the X-ray, ultraviolet, and optical regions of astrophysical plasmas.