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.

Combustion Characteristics of the Mustard Methyl Esters

Abstract: Mustard Methyl Esters (further biodiesel) and regular diesel fuel were tested in direct injection diesel engine. Analysis of experimental data was supported by an analysis of fuel injection and combustion characteristics. Engine fuelled with biodiesel had increased brake specific fuel consumption, reduced nitrogen oxides emission and smoke opacity, moderate increase in carbon monoxide emission with essentially unchanged unburned hydrocarbons emission. Increase in fuel consumption was attributed to lesser heating value of biodiesel and partially to decreased fuel conversion efficiency. Analysis of combustion characteristics revealed earlier start of injection and shorter ignition delay period of biodiesel. Resulting decrease in maximum rate of heat release and cylinder pressure was the most probable reason for reduced emission of nitrogen oxides. Analysis of combustion characteristics also showed that cetane index determined by ASTM Method D976 is not a proper measure of ignition quality of biodiesel. Conclusion was made on applicability of mustard oil as a source for commercial production of biodiesel in Pakistan. Potentialities of on improving combustion and emissions characteristics of diesel engine by reformulating biodiesel were discussed.

Humidity effect on organic semiconductor NiPc films deposited at different gravity conditions

Abstract: In this study, thin films of Nickel Phthalocyanine (NiPc) were deposited by centrifugation at high gravity (70g), and also at normal gravity (1g) conditions to fabricate humidity sensors. Ceramic alumina sheet, coated with silver electrodes, having interelectrode distance of 0.2l mm were used to assess the electrical properties of the sensors. Room temperature capacitance and impedance variations were measured as a function of relative humidity ranging from 25% ~ 95% at 1 kHz frequency. It was observed that sensors fabricated at 70g were more sensitive compared to sensors fabricated at 1g. Sensors fabricated at 70g exhibited 1.8 times decrease in their impedance and1.5 times increase in their capacitance at peak ambient humidity. SEM images showed more roughness for the films deposited at 70g compared to films deposited at 1g. It was assumed that surface irregularities might have increased active surface area of 70g sensors hence changed the electrical response. Impedance-humidity and capacitance-humidity relationships were modeled and a good agreement was observed between experimental and modeled data. Experimental data showed that NiPc films could be useful for instrumentation industry to fabricate organic humidity sensors.

Amplitude and phase engineered all-dielectric metasurface for finite energy self-accelerating airy beam generation

Abstract: Metasurfaces are subwavelength artificially engineered devices which serve as the best alternative for conventional bulk optical components, owing to their unique capability to control and manipulate the intensity, phase, and polarization of the electromagnetic waves. They have emerged as an exceptional podium for the miniaturization and on-chip implementation of many diverse prodigies such as 3D imaging, lensing, beam shaping and light-twisting, etc. Regardless of the rapid development in this domain, metasurfaces exhibiting metallic scatterers are still subjected to poor transmission efficiency due to high ohmic losses and optical absorptivity. In this work, we demonstrate a transmission-based highly efficient alldielectric metasurface to generate finite energy accelerating 1D and 2D airy beams at the visible wavelength of 633 nm by concurrently manipulating the phase and the amplitude of the cross-polarized transmitted light. The proposed metasurface employs hydrogenated amorphous silicon(a-Si:H) nanoresonators which offers a remarkable lead in term of efficiency over metals and other high-index dielectrics (such as TiO2 and GaN) with respect to cost, CMOS compatibility and ease of fabrication. Here the orientation of the nano-bars is varied to control the phase and polarization whereas its geometric parameters are optimized to tune the cross-polarized transmission amplitude. In comparison to the previously reported work, we achieved sufficiently high cross-polarized transmission efficiency i.e., 73%. Owing to its unique characteristics of being self-accelerating, diffraction free and self-healing, this Airy beam based metasurface will aid us to develop planar 2D devices for plentiful applications such as Super-resolution fluorescence imaging, light-sheet microscopy, nano-particles trapping, and optical bullets.

Religious tourism in Pakistan: Scope, obstacles & strategies

Abstract: Religious tourism is a thriving yet largely unexplored industry in Pakistan; a country packed with landmarks of various religious ethnicities. With a hefty economic potential, religious tourism in ...

Hybrid opto-digital signal processing in 112 Gbit/s DP-16QAM and DP-QDB transmission for long-haul large-$$\hbox {A}_\mathrm{eff}$$Aeff pure-silica-core fiber links

Abstract: By means of numerical simulations, we demonstrated that all-optical signal processing methods (XPM-suppressor module and in-line nonlinear equalization) significantly increase the system performance of digital nonlinear compensation (digital backward propagation) and improve the system performance in five-channel 112 Gbit/s DP-16QAM and DP-QDB transmission over 2400 km large- effective-area pure-silica-core fiber ($$\hbox {LA}_\mathrm{eff}$$LAeff-PSCF). The system performance is quantified with the help of Q-factor (dB) for both dispersion-managed and nondispersion-managed fiber links.