A method of estimating the standard gibbs free energy of formation

Standard Gibbs free energy of formation (ΔG_f⁰), an important property needed in design calculations has been estimated using molar refraction, R_M. The linear relationships derived between ΔG_f⁰ and R_M tested with the data on 8 series of hydrocarbons at 228 compounds yielded average deviations comparable to the methods cited in recent literature. The method can be used as an alternative to the existing ones, because of its simplicity combined with reasonable accuracy.     

Evaporated Thin Films of CdS and CdTe: Optimization for Photovoltaic Applications

Thin films of cadmium sulphide and cadmium telluride have been prepared by thermal evaporation under various conditions of deposition. These films have been characterized optically. electrically and for structure determination. The results of these characterizations along with the initial results of all thin film CdS/CdTe solar cells are presented in this paper     

IP address allocation protocols in vehicular ad hoc networks

In vehicular ad hoc networks (VANETs), communication takes place between vehicles to vehicles, the vehicles to the road side units, and vice-versa. The basic purpose of these communications is to share and exchange tremendous amount of data and information. For efficient information sharing, a systematic and structured connection establishment algorithm is needed. In VANETs, each connected node of the network need to be assigned a unique address. Hence, an algorithm is needed for the proper assignment of unique address to all nodes in the network. This paper explains different types of IP address protocols in VANETs. We have also explained advantage and disadvantage of existing IP address allocation protocols in VANETs.     

The effect of hydrogen in the mechanism of aluminum-induced crystallization of sputtered amorphous silicon using scanning Auger microanalysis

The metal-induced crystallization (MIC) of hydrogenated sputtered amorphous silicon (a-Si:H) using aluminum has been investigated using X-ray diffraction (XRD) and scanning Auger microanalysis (SAM). Hydrogenated, as well as non-hydrogenated, amorphous silicon (a-Si) films were sputtered on glass substrates, then capped with a thin layer of Al. Following the depositions, the samples were annealed in the temperature range 200 °C to 400 °C for varying periods of time. Crystallization of the samples was confirmed by XRD. Non-hydrogenated films started to crystallize at 350 °C. On the other hand, crystallization of the samples with the highest hydrogen (H₂) content initiated at 225 °C. Thus, the crystallization temperature is affected by the H₂ content of the a-Si. Material structure following annealing was confirmed by SAM. In this paper, a comprehensive model for MIC of a-Si is developed based on these experimental results.     

Modeling hydrogen storage on Mg–H2 and LiNH2 under variable temperature using multiple regression analysis with respect to ANOVA

The world is facing a major problem due to the depletion of conventional energy sources. Hydrogen is considered one of the most promising sources of energy. Recently, one of the problems facing utilization of hydrogen energy is the storage. Therefore, finding materials to store hydrogen based on the adsorption/desorption methodology (i.e. metal hydrides) is considered extremely vital issue. During this work two candidate materials (i.e. Mg–H₂ and LiNH₂) were investigated at different temperatures (25–45 °C). The results revealed that both candidate materials possessed long cycle life and cyclibility which opens the wide door to use these materials in vehicular applications. On the other hand the generated mathematical models based on the multiple regression analysis with respect to ANOVA showed that increasing temperature will increase the weight of hydrogen adsorption for both candidate materials.     

Biogas production enhancement by soya sludge amendment in cattle dung digesters

Biogas energy production from cattle dung is an economically feasible and eco-friendly in nature. But dependence only on cattle dung is a limiting factor. Rich nitrogen containing substrate addition to extra carbohydrate digester like cattle dung could improve the biogas production. Detailed performance of the digesters at different ratios of cattle dung and soya sludge has been discussed in this paper considering the cold countries climate. Soya sludge substrate not only has high nitrogen content of 4.0–4.8% but it also has high percentage of volatile solids content in the range of 97.8–98.8%. Soya sludge addition also improved the manurial value of the digested slurry and also improved the dewater-ability of the sludge. Results indicated an increment of 27.0% gas production at 25.0% amendment of soya sludge in non-homogenized cattle dung (NCD) digester. The amount of gas production increased to 46.4% in case of homogenized cattle dung (HCD) with respect to NCD feed at the same amendment.     

Surface and Interface Analyses of UHV Evaporated Nb/AlOx/Nb Tri-layers

We have prepared Nb thin films with e-beam evaporation under UHV conditions. Al thin films were deposited by resistive heating in the UHV chamber. The preparation of these films and the tri-layers of Nb/AlOx/Nb were intended for their use in Josephson junctions. The surface studies of these films were undertaken by using scanning electron microscope and atomic force microscope in the non-contact mode, whilst the interface analysis was carried out by depth profiling using scanning Auger microprobe. These studies have revealed that Nb films grown on AlOx are smoother than the ones grown on Si. Further, it is seen that Al diffuses into Nb on both sides and that the interface is very broad. This intermixing of various materials results in the failure of the tri-layers when subjected to application in SQUIDs.     

Risk factors for contralateral breast cancer in Chennai (Madras), India

BACKGROUND: This is the first cohort study conducted in India to identify risk factors for contralateral breast cancer (CBC) among patients with first primary breast cancer. METHODS: Patients with first primary breast cancer diagnosed in 1960-1989 at the Cancer Institute (WIA) in Chennai, India, were followed-up until 31 December 1994. The risk of CBC was assessed among unilateral breast cancer (UBC) patients who survived for >12 months following the diagnosis of breast cancer and did not develop a second cancer (n = 2665) and among those who developed a CBC > or =12 months after the diagnosis of breast cancer (n = 39). RESULTS: The age-adjusted incidence of CBC among women with UBC was seven times the incidence (per single breast) in the general population. Among women with UBC the relative risk (RR) was 4.5 (95% CI: 1.1-19.6) comparing those with and without a history of breast cancer in the mother, and 2.8 (95% CI: 1.2-6.7) comparing age at first birth 21-25 versus earlier. The RR was 0.3 (95% CI: 0.1-0.6) comparing those with and without hormone therapy for their UBC. Radiotherapy for the UBC had no significant effect on the incidence of CBC. CONCLUSION: Positive family history of breast cancer and later age at first childbirth emerged as stronger risk factors for CBC than UBC. Hormone therapy reduces the risk of CBC.