Showing papers by "Ghulam Ishaq Khan Institute of Engineering Sciences and Technology published in 2015"

On Comparison of Series and Numerical Solutions for Flow of Eyring-Powell Fluid with Newtonian Heating And Internal Heat Generation/Absorption.

Abstract: In this paper, we have investigated the combined effects of Newtonian heating and internal heat generation/absorption in the two-dimensional flow of Eyring-Powell fluid over a stretching surface. The governing non-linear analysis of partial differential equations is reduced into the ordinary differential equations using similarity transformations. The resulting problems are computed for both series and numerical solutions. Series solution is constructed using homotopy analysis method (HAM) whereas numerical solution is presented by two different techniques namely shooting method and bvp4c. A comparison of homotopy solution with numerical solution is also tabulated. Both solutions are found in an excellent agreement. Dimensionless velocity and temperature profiles are plotted and discussed for various emerging physical parameters.

Newtonian heating in stagnation point flow of Burgers fluid

Abstract: The Newtonian heating effects in the stagnation point flow of a Burgers fluid are addressed in this paper. The boundary layer flow problems are stated in the spatial domain from zero to infinity. The solution expressions for the velocity and the temperature are obtained and examined for the influential variables. The tabulated values show comparison with the previous results. It is observed that the obtained results are in good agreement with the existing results in limiting sense.

Graphene-embedded carbon nanofibers decorated with Pt nanoneedles for high efficiency dye-sensitized solar cells

Abstract: Graphene-embedded carbon nanofibers (GCNFs) were developed as a new counter electrode nanomaterial for high efficiency dye-sensitized solar cells (DSCs). GCNFs were produced by electrospinning polyacrylonitrile (PAN) with graphene nanoplatelets followed by stabilization and carbonization. GCNFs decorated with surface-attached platinum nanoneedles (GCNFs-PtNNs) were subsequently prepared by a redox reaction and then deposited onto fluorine doped tin oxide (FTO) glass to make a counter electrode for DSCs. Graphene inside the carbon nanofibers and Pt nanoneedles on the surface demonstrated a synergistic effect to improve the DSC performance. Compared to DSCs with conventional planar Pt counter electrodes, the DSCs with GCNFs-PtNNs significantly improved the energy conversion efficiency from ∼8.63% to ∼9.70% using a mask under AM1.5 illumination. This is the highest conversion efficiency so far with a carbon nanofiber based counter electrode.

A Kinect-Based Sign Language Hand Gesture Recognition System for Hearing- and Speech-Impaired: A Pilot Study of Pakistani Sign Language

Abstract: Sign language provides hearing and speech impaired individuals with an interface to communicate with other members of the society. Unfortunately, sign language is not understood by most of the common people. For this, a gadget based on image processing and pattern recognition can provide with a vital aid for detecting and translating sign language into a vocal language. This work presents a system for detecting and understanding the sign language gestures by a custom built software tool and later translating the gesture into a vocal language. For the purpose of recognizing a particular gesture, the system employs a Dynamic Time Warping (DTW) algorithm and an off-the-shelf software tool is employed for vocal language generation. Microsoft(®) Kinect is the primary tool used to capture video stream of a user. The proposed method is capable of successfully detecting gestures stored in the dictionary with an accuracy of 91%. The proposed system has the ability to define and add custom made gestures. Based on an experiment in which 10 individuals with impairments used the system to communicate with 5 people with no disability, 87% agreed that the system was useful.

Dye-Sensitized Solar Cells Based on Porous Hollow Tin Oxide Nanofibers

Abstract: Porous hollow tin oxide (SnO2) nanofibers and their composite with titanium dioxide (TiO2) particles (Degussa P25) were investigated as a photoanode for dye-sensitized solar cells. Incorporation of TiO2 particles in porous hollow SnO2 fibers enhanced the power conversion efficiency ( $\eta )$ from 4.06% to 5.72% under 100-mW/cm $^{2}$ light intensity. The enhancement of efficiency was mainly attributed to increase in current density ( $J_{\rm sc}$ ) and improvement in fill factor (FF). Increase in $J_{\rm sc}$ was caused by higher dye loading as indicated by UV–Vis absorption spectra and the improvement in FF was attributed to faster charge transport time as obtained from transient analysis. The microstructure of SnO2 fibers was studied using transmission electron microscope, scanning electron microscope, and X-ray diffraction. The electron transfer and recombination life times were studied using transient analysis, whereas interfacial charge transfer was studied using electrochemical impedance spectroscopy.

Surface-type nonvolatile electric memory elements based on organic-on-organic CuPc-H2Pc heterojunction*

Abstract: A novel surface-type nonvolatile electric memory elements based on organic semiconductors CuPc and H2Pc are fabricated by vacuum deposition of the CuPc and H2Pc films on preliminary deposited metallic (Ag and Cu) electrodes. The gap between Ag and Cu electrodes is 30–40 μm. For the current–voltage (I–V) characteristics the memory effect, switching effect, and negative differential resistance regions are observed. The switching mechanism is attributed to the electric-field-induced charge transfer. As a result the device switches from a low to a high-conductivity state and then back to a low conductivity state if the opposite polarity voltage is applied. The ratio of resistance at the high resistance state to that at the low resistance state is equal to 120–150. Under the switching condition, the electric current increases ~ 80–100 times. A comparison between the forward and reverse I–V characteristics shows the presence of rectifying behavior.

A Review of TiNiPdCu Alloy System for High Temperature Shape Memory Applications

Abstract: High temperature shape memory alloys (HTSMAs) are important smart materials and possess a significant potential to improve many engineering systems. Many TiNi-based high temperature ternary alloy systems have been reported in literature including TiNiPd, TiNiPt, TiNiZr, TiNiAu, TiNiHf, etc. Some quaternary additions of certain elements in the above systems have been successful to further improve many important shape memory and mechanical properties. The success criteria for an HTSMA become strict in terms of its cyclic stability, maximum recoverable strain, creep resistance, and corrosion resistance at high temperatures. TiNiPdCu alloy system has been recently proposed as a promising HTSMA. Unique nanoscaled precipitates formed in TiNiPdCu-based HTSMAs are found to be stable at temperatures above 773 K, while keeping the benefits of ease of fabrication. It is expected that this alloy system possesses significant potential especially for the high temperature shape memory applications. Till now many research reports have been published on this alloy system. In the present work, a comprehensive review of the TiNiPdCu system is presented in terms of thermomechanical behavior, nanoscale precipitation mechanism, microstructural features, high temperature shape memory and mechanical properties, and the important parameters to control the high temperature performance of these alloys.

Photovoltaic effect in single-junction organic solar cell fabricated using Vanadyl Phthalocyanine soluble derivative

Abstract: Purpose – The purpose of this paper is to study the optical and electrical characteristics of a single-junction solar cell based on a green-colour dye vanadyl 2,9,16, 23-tetraphenoxy-29H, 31H-phthalocyanine (VOPcPhO). The use of soluble vanadyl phthalocyanine derivative makes it very attractive for photovoltaic applications due to its tunable properties and high solubility. Design/methodology/approach – A photoactive layer of VOPcPhO has been sandwiched between indium tin oxide (ITO) and aluminium (Al) electrodes to produce a ITO/PEDOT:PSS/VOPcPhO/Al photovoltaic device. The VOPcPhO thin film is deposited by a simple spin coating technique. To obtain the optimal thickness for the solar cell device, different thicknesses of the photoactive layer, achieved by manipulating the spin rate, have been investigated. Findings – The device exhibited photovoltaic effect with the values of Jsc, Voc and FF equal to 5.26 × 10-6 A/cm2, 0.621 V and 0.33, respectively. The electronic parameters of the cell have been obtai...

Reduction of Four Wave Mixing by employing circular polarizers in DWDM optical networks

Abstract: Next generation optical communication networks demand the use of the lower channel spacing and high input power in Wavelength Division Multiplexing (WDM) systems to achieve higher data rates. However, decreasing channel spacing and increasing input power create nonlinear effects including Four Wave Mixing (FWM). In this paper a method has been introduced in which alternative circular polarizers are used to change the polarization of input pulses into right and left handed polarized pulses before multiplexer which results in reduction of FWM. With the help of this technique we can completely eliminate FWM by optimizing optical network's parameters. Exhaustive set of simulations has been performed in Optisys and system's performance has been calculated.

First-forbidden transitions and stellar β-decay rates of Zn and Ge isotopes

Abstract: First-forbidden (FF) charge-changing transitions become relatively important for nuclei as their proton number increases. This is because the strength of allowed Gamow–Teller (GT) transitions decreases with increasing Z. The FF transitions play an important role in reducing the half-lives compared to those calculated from taking the GT transitions alone into account. In this paper we calculate allowed GT as well as and transitions for neutron-rich Zn and Ge isotopes. Two different pn-QRPA models were used with a schematic separable interaction to calculate GT and FF transitions. Half-lives calculated after inclusion of FF transitions were in excellent agreement with the experimental data. Our calculations were also compared to previous QRPA calculations and were found to be in better agreement with measured data. Stellar β-decay rates were calculated for these nuclei including allowed GT and unique FF transitions for astrophysical applications. 86,88Ge has a sizeable contribution to the total stellar rate from unique FF transitions.

Real-Time Vehicle Recognition and Improved Traffic Congestion Resolution

Abstract: An intelligent traffic management system (E-Traffic Warden) is proposed, using image processing techniques along with smart traffic control algorithm. Traffic recognition was achieved using cascade classifier for vehicle recognition utilizing Open CV and Visual Studio C/C++. The classifier was trained on 700 positive samples and 1140 negative samples. The results show that the accuracy of vehicle detection is approximately 93 percent. The count of vehicles at all approaches of intersection is used to estimate traffic. Traffic build up is then avoided or resolved by passing the extracted data to traffic control algorithm. The control algorithm shows approximately 86% improvement over Fixed-Delay controller in worst case scenarios.

Sensitivity enhancement of OD- and OD-CNT-based humidity sensors by high gravity thin film deposition technique

Abstract: The humidity sensing properties of the thin films of an organic semiconductor material orange dye (OD) and its composite with CNTs deposited at high gravity conditions have been reported. Impedance, phase angle, capacitance and dissipation of the samples were measured at 1 kHz and room temperature conditions. The impedance decreases and capacitance increases with an increase in the humidity level. It was found that the sensitivity of the OD-based thin film samples deposited at high gravity condition is higher than the samples deposited at low gravity condition. The impedances and capacitance sensitivities of the of the samples deposited under high gravity condition are 6.1 times and 1.6 times higher than the films deposited under low gravity condition.

Synthesis of C–N–Y tri-doped TiO2 photo-catalyst for MO degradation and characterization

Abstract: In this research C–N–Y tri-doped TiO2 nanopowders were synthesized by the sol–gel method. The C–N–Y TiO2 photo-catalyst was prepared using hexamine and yttrium nitrate Hexahydrate as the dopant precursors. Methyl-orange (MO) was used to study the photocatalytic performance of the doped TiO2 under UV irradiation. The synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, Transmission electron microscopy, Photoluminescence and Field emission scanning electron microscopy. The tri-doped sample with 8% N, 0.4% Y and 1.5% C exhibited enhanced photocatalytic efficiencies. After 100 min of irradiation with UV light, 87% of MO was decomposed by C–N–Y tri-doped TiO2 sample. It is suggested that the co-activity of C and N could make the intra-gap localized states above the valence band of TiO2, and carbon in TiO2 structure causes carbonate species to appear. These carbonate species acted as photosensitizer on the TiO2 surface to promote photo-catalytic activity of the as synthesized sample.

Linear and nonlinear system identification techniques for modelling of a remotely operated underwater vehicle

Abstract: As opposed to classical mathematical-based modelling approach, this paper reports a black-box system identification technique for characterising the dynamics of a remotely operated vehicle (ROV). A linear system identification technique is employed to model the vehicle dynamics. However, use is also made of advance neural networks-based nonlinear system identification approach to model rudder-depth channel nonlinear behaviour. Different model validity tests are also employed to instil confidence in the identified linear and nonlinear ROV dynamic models. High fidelity models obtained for the multi-degree-of-freedom vehicle are of immense importance for developing ROV simulators, pilot training and autopilot design.

Enhancement of electrical properties of vanadyl phthalocyanine derivative by PCBM

Abstract: Purpose – The purpose of this paper is to investigate the effect of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) on improvement of physical and electrical properties of vanadyl phthalocyanine derivative. The correlation between the physical characteristics of the active layers, comprising vanadyl 2,9,16, 23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO) and PCBM, and the electrical properties of metal/organic/metal devices have been studied. The use of soluble vanadyl phthalocyanine derivative makes it very attractive for a variety of applications due to its tunable properties and high solubility. Design/methodology/approach – The sandwich type structures Al/VOPcPhO/Al and Al/VOPcPhO:PCBM/Al were fabricated by spin casting the active organic layers between the top and bottom (aluminum) electrodes. The stand-alone (VOPcPhO) and composite (VOPcPhO:PCBM) thin films were characterized by X-ray diffraction, atomic force microscopy, UV/Vis and Raman spectroscopy. The electronic properties of the metal/organ...

Combustion and Emissions Characteristics of Jatropha Methyl Esters in a Direct Injection Diesel Engine

Abstract: Engine fueled with Jatropha biodiesel showed reduced nitrogen oxides, unburned hydrocarbons, and smoke emissions with a moderate increase in carbon monoxide emission at high loads. Increased by 16% fuel consumption at rated load was attributed to lesser by 10% heating value of biodiesel and decreased by 6% fuel conversion efficiency. Analysis of combustion characteristics revealed an earlier start of injection and shorter ignition delay of biodiesel. Resulting decrease in maximum rate of heat release and peak cylinder pressure was the main reason for reduced NOx emission. It was shown that cetane index determined by the ASTM D976 method is not a proper measure of the ignition quality of biodiesel.

Raman spectroscopy and microstructure of the pulsed laser-treated silver–anatase thick film

Abstract: The present research describes the effect of laser pulses on crystalline titanium dioxide thick film with self-adsorbed silver ions. Anatase film of up to 4 µm thickness was deposited on ITO glass by doctor-blading technique. The film was heated at 450 °C for 60 min and cooled before immersion in silver nitrate aqueous solution. After drying, films were subjected to nanosecond pulses of the excimer laser, and their structural, microstructural and optical properties were investigated. Scanning electron microscopy and EDX analysis revealed the formation of silver nanoparticles (SNPs) dispersed in the anatase matrix. There was no significant change in the anatase structure as revealed by Raman spectroscopy. The intensity of Raman signals from pristine anatase film was increased after the laser treatment of silver ions on the film. This observation is associated with the phenomenon of localized surface plasmon resonance conferred by the crystalline SNPs. The results obtained by the UV–visible spectroscopy also support the role of SNPs to enhance the photoabsorption of the anatase film in the visible region.

Spectrum Occupancy and Residual Service Analysis in CRNs Using a Multi-Server Queueing Model

Abstract: Cognitive radio technology enables secondary users (SUs) to opportunistically access the unused or sparsely utilized spectrum by primary users (PUs) without causing any harmful interference to PUs. Consequently, spectrum occupancy modeling appears as an essential task in cognitive radio networks (CRNs). In this paper, we model spectrum occupancy using a queueing theory based approach in order to evaluate the performance of CRNs in terms of network capacity and number of cognitive radio users waiting for services etc. The queue adopted in this model has variable service capacity and can be considered as a multi-service queue with server failure where each channel acts as a server. When a channel is occupied by a PU, it is regarded as a server failure. Using the probability generating function, the closed-form expressions for various performance parameters are derived. Numerical results on the remaining services for SUs and the expected number of SUs as the CRN capacity varies are illustrated.

Computational Intelligence-based Entertaining Level Generation for Platform Games

Abstract: With computers becoming ubiquitous and high resolution graphics reaching the next level, computer games have become a major source of entertainment. It has been a tedious task for game developers to measure the entertainment value of the computer games. The entertainment value of a game does depend upon the genre of the game in addition to the game contents. In this paper, we propose a set of entertainment metrics for the platform genre of games. The set of entertainment metrics is proposed based upon certain theories on entertainment in computer games. To test the metrics, we use an evolutionary algorithm for automated generation of game rules which are entertaining. The proposed approach starts with an initial set of randomly generated games and, based upon the proposed metrics as an objective function, guides the evolutionary process. The results produced are counterchecked against the entertainment criteria of humans by conducting a human user survey and a controller learning ability experimen...

Vibration induced failure analysis of a high speed rotor supported by active magnetic bearings

Abstract: Active Magnetic Bearings (AMBs) are increasingly used in various industries and a quick re-levitation of AMBs supported high speed flexible rotor is necessary in case of vibration induced failure. A robust fault diagnosis algorithm is presented to detect suspected saturation type of nonlinearity associated with a power amplifier. A five degree-of-freedom AMB system consisting of four opposing pair of radial magnets and a pair of axial magnets is considered. In this paper failure of an industrial grade AMB system is investigated using Sinusoidal Input Describing Function (SIDF) method. SIDF predicts the gain and frequency at which failure occurs. It is demonstrated that the predicted frequency is in agreement with the frequency at which failure occurs.

Effect of compound parabolic concentrator on performance of photovoltaic module

Abstract: Photovoltaic module, used to convert solar energy into electrical energy, is not popular among common people due to its low electrical output. This paper presents the experimental investigation of photovoltaic module with Compound Parabolic Concentrator. Proposed system has one major objective i.e., to increase the electrical power of photovoltaic module. The experimental results (taken in winter at GIK Institute) show that electrical power of proposed system is 1.32 times more than photovoltaic module. Proposed system is simple, so conventional photovoltaic system can be easily upgraded to subject design in order to increase the electrical power. This system can be used for large photovoltaic applications.

Identification of essential regulatory elements responsible for the explicit expression of IL-28Rα and their effect on critical SNPs using in-Silico methods.

Abstract: IL-28Rα and IL10Rβ collectively construct a fully functional hetero-dimeric receptor for type III interferons (IFNs). IL-28Rα is the private chain for type III IFNs since their involvement in any other pathway has not been reported yet and they are highly expressed in response to certain viral attack or cancers. IL-28Rα is specific in their expression pattern and it expresses within few cell types only. The regulatory mechanisms governing the expression of IL-28Rα at the molecular level are not completely known yet and need to be scrutinized at primary levels. In the present study, various in-silico techniques were applied and it was observed that AP1-2, STAT 1-6, P-53, LyF-1 (lymphoid transcription factor), c-Jun, PU.1, CREB (cAMP response element-binding), PLAG (pleotropic adenoma gene), MYOD (myoblast determination protein 1), NOFL and KLFS as transcription factors that are selected with preference. Interestingly AP-2, c-Jun, LyF-1, STAT, NF-Y and P53 have also been reported in literature recently as some of the key regulatory elements as well. Based on the fact that interlinking between different interferon stimulation genes (ISGs) is also not very clear and induction of one type of interferon can affect the efficacy of the other, we found that IFN-λ4 induction can increase the expression of IL-28Rα, similar to IFN-λ3 but contrary to type I IFNs, which has either no effect on the expression of IL-28Rα or can down regulate its expression at higher concentrations (data not published).

A new proposed hierarchy for renewable energy generation to distribution grid integration

Abstract: This paper presents a new hierarchy about the study of renewable energy generation, its transmission, energy storage and adding this power to distribution grid level. Simulation are verifying the feasibility and working. The main purpose of this study is to propose a feasible solution to replace fossil fuel energy sources to renewable energy sources without changing current working distribution grids setup. This paper will describe main components of this hierarchy including DC-DC converters, DC transmission, energy storage devices and grid integration. DC-DC converters are converting generated voltages to high voltages to transmit them on DC transmission line. Similarly a DC-DC step down converter is being used for step down purpose for using transmission line voltage to low level voltage for energy storage purpose and for grid integration on distribution side. DC-AC inverter is using old distribution grid signal as sample and converter DC into AC according to it. Simulation results verify the efficient working of all converters and completely stable system.