Ghulam Ishaq Khan Institute of Engineering Sciences and Technology

About: Ghulam Ishaq Khan Institute of Engineering Sciences and Technology is a education organization based out in Topi, Pakistan. It is known for research contribution in the topics: Thin film & Quantum efficiency. The organization has 618 authors who have published 940 publications receiving 10674 citations.

Water Absorption Resistance Study of HTV Silicone Rubber-Based Hybrid Composites

Abstract: Silicone rubber-based insulating polymers are extensively used in high voltage outdoor applications due to their high hydrophobicity and better withstand performance. However, the main problem with polymeric composites is their aging due to external environmental stresses (e.g. direct sunlight, high humidity and temperatures, ultraviolet radiations, etc.) as well as strength of the applied electrical field. In the present work, for examining weight gain, hydrophobicity, and hardness, five different types of HTV silicone rubber-based hybrid composites are prepared. All the samples are reinforced with micro-alumina (20 wt. %) and different concentrations of silica fillers. Material samples are immersed in distilled and boiling water for 24h and 2h, respectively. For analysis, hydrophobicity, weight gain and hardness tests are conducted. The results of the performed tests indicated that the sample filled with 6 wt. % of nano-silica has less percentage gain in weight due to water absorption compared to the other hybrid composites. The sample with the same composition showed high hydrophobicity as well.

Fe–TiB2 composites produced through casting technique

Abstract: A hypereutectic composition of α-Fe(Co)–TiB2 composite was produced in strip and rod form through casting technique. The phases observed in the composite consisted of α-Fe(Co) and TiB2. Primary TiB...

Nickel Phthalocyanine-Based Sandwich-Type Photocapacitive Illumination Sensors for Environmental Monitoring

Abstract: In this paper, the properties of organic semiconductor nickel phthalocyanine (NiPc)-based photocapacitive illumination sensors are reported. Thin films of NiPc and aluminum were deposited sequentially by vacuum evaporation on ITO-coated glass substrates to form ITO/NiPc/Al sensors with different thicknesses of NiPc, i.e., 50, 100 and 150 nm. The effective surface area of each cell was 80 mm2 (8 × 10 mm). The cells were then annealed at 150°C for 2 h under ambient conditions to improve the uniformity of the films. The effects of film thickness and illumination with a filament lamp on the capacitance of the sensors were studied. Under filament lamp illumination of up to 2,000 lx the relative photocapacitance of the sensors increased by 50%. It was assumed that the photocapacitive response of the sensors is associated with polarization caused by the transfer of photogenerated electrons and holes. The illumination-dependent capacitance properties of these sensors make them attractive for use in multimeters and instruments for environmental monitoring of illumination.

Analysis of wall curling in incremental forming of a sheet metal: role of residual stresses, stretching force and process conditions

Abstract: The present work, first detailed study in its nature, introduces wall curl as a source of geometric inaccuracy in the novel Incremental Sheet Forming (ISF) process, and aims at investigating role of the residual stresses, stretching force and process conditions on formation of the curl. A series of metal components are formed by varying the conditions. The curl height, residual stresses (surface, mean and equivalent) and stretching force are determined and their correlations are analyzed. The analysis reveals that curling is strongly influenced by the residual stresses in a way that the curl height increases linearly as their magnitude increases. Similarly, an increase in degree of non-uniformity in the through-thickness stress distribution promotes curling. The increase in stretching force, however, diminishes curling reasoning to reduction in the residual stresses. As regard the conditions, feed rate does not show any effect while mild annealing, greater tool diameter, smaller step size, and lower forming angle and rotation are found conducive to minimize curling. The geometric errors in wall and bottom of the produced parts (i.e., curling and pillowing) are found to show an interesting inverse relationship. The reported results are very useful to deepen the process mechanics and will also prove helpful in simultaneously controlling the two types of errors.