Krol J.B.,Warsaw University of Technology |
Khan R.,University of Engineering & Technology, Peshawar |
Collop A.C.,De Montfort University
Road Materials and Pavement Design | Year: 2017
X-ray computed tomography (CT) and laboratory permeability techniques were applied to study the internal properties of porous asphalt mixture. Specimens containing aggregate of different gradations and of different mineral compositions were prepared in the laboratory. The air voids of all the specimens were determined in the laboratory and the specimens were then scanned in X-ray CT. The same samples were then tested for laboratory permeability. The active air voids and contact points of aggregate with nearby aggregate particles were determined from X-ray CT images. The laboratory permeability test results were found in comparison with X-ray CT values of voids’ internal connectivity. A comparatively high permeability value was observed for porous asphalt with maximum aggregate size irrespective of its mineral composition. The size of air voids and volume of active (connected) air voids were also found high for mixtures made up of large aggregate size. The difference in mineral composition of aggregate was found to have considerably less effect on permeability of porous asphalt. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Rehman F.,Allama Iqbal Open University |
Khan M.I.,Heriot - Watt University |
Sadiq M.,University of Engineering & Technology, Peshawar |
Malook A.,Sarhad University of Science and Information Technology
Journal of Molecular Liquids | Year: 2017
This article addresses the MHD flow of micropolar carbon-water nanofluid in the presence of rotating frame. Two types of carbon nanotubes (single and multi-walls) are homogeneously dispersed in the base fluid (water). Convective heat transfer phenomenon is also retained in this study. With the help of the similarity transformation, a mathematical model is developed by transforming the partial differential equation into ordinary differential equation. Further it is then solved analytically by using homotopy analysis method HAM. The impact of emerging parameters, skin friction coefficient and Nusselt number are also discussed in detail. It is observed that temperature profile decreases with the increase in porosity parameter and nanoparticle volume fraction while enhances for higher values of Biot number. Further Micro rotation profile increases with the increase in coupling parameter N1 and Reynolds number R while decreases with increase in Biot number Bi and volume fraction ϕ. © 2017 Elsevier B.V.
Malik A.,University of Engineering & Technology, Peshawar |
Shakir A.S.,University of Engineering and Technology Lahore |
Ajmal M.,University of Engineering & Technology, Peshawar |
Khan M.J.,University of Peshawar |
Khan T.A.,University of Engineering & Technology, Peshawar
Water Resources Management | Year: 2017
The AquaCrop model was analyzed for simulating sugar beet crop production under four irrigation regimes, three mulching conditions and three furrow irrigation systems in semi-arid region of Pakistan. Irrigation regimes were full irrigation (FI), 20% deficit irrigation (DI20), 40% deficit irrigation (DI40) and 60% deficit irrigation (DI60). The mulching practices were No-mulch (NM), black film mulch (BFM) and straw mulch (SM). The furrow irrigation systems were conventional ridge-furrow (CRF) system, medium raised-bed (MRB) system and wide raised-bed (WRB) system. The model was calibrated and validated using the independent data sets of full irrigation and deficit irrigation regimes collected during 2011–12 cropping season. The model performance was evaluated by using different statistical indicators such as Root Mean Square Error (RMSE), index of agreement (dindex), and Nash–Sutcliffe Efficiency (NSE). These indicators showed that the model fairly simulated sugar beet canopy cover for all treatments with 3.00 ≤ RMSE ≤ 16.89, 0.84 ≤ dindex ≤ 0.97, and 0.76 ≤ NSE ≤ 0.99. For biomass and root yield, the model performance was excellent under all full irrigation (FI) and mild deficit irrigation (DI20) treatments with RMSE ranged between 0.07 and 1.17, dindex between 0.48 and 0.84, and NSE between 0.42 and 0.86, respectively. However the low values of dindex (0.10 and 0.13) and NSE (−69.32 and −30.63) showed that the model overestimated both the biomass and root yield when 20% deficit irrigation was applied without mulch in WRB system. The model also over estimated the yield and biomass when 40% deficit irrigation was applied in CRF system. The highest overestimation (dindex: 0.10 to 0.11; NSE: −50.92 to −70.55) was observed when highest stress level (DI60) was applied in the presence of BFM in CRF system. Based on the model’s overall performance, the AquaCrop application is recommended for developing efficient farm water management strategies in the semi-arid regions. © 2017 Springer Science+Business Media B.V.
Tahir F.A.,National University of Sciences and Technology |
Arshad T.,National University of Sciences and Technology |
Ullah S.,University of Engineering & Technology, Peshawar |
Flint J.A.,Loughborough University
Microwave and Optical Technology Letters | Year: 2017
This paper presents a novel compact unilayer frequency selective surface (FSS) for ultra-wideband (UWB) applications particularly for gain enhancement of printed antennas. The proposed FSS unit cell consists of simple metallic patterns printed on both sides of 14 mm × 14 mm FR4 substrate. The proposed FSS has very low transmission co-efficient and linearly decreasing reflection phase over the bandwidth of 9 GHz in 3–12 GHz range, which makes it suitable candidate to provide in-phase reflection for UWB antennas. For the validation of gain-enhancement capability, the FSS is paired with a general monopole UWB antenna demonstrating an average gain improvement of 4 dB. The antenna composite has a maximum gain of 8.9 dBi. © 2017 Wiley Periodicals, Inc.
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: INCO.2013-1.6 | Award Amount: 335.55K | Year: 2013
CASCADE aims to provide the foundation for a future INCONET programme targeting South Asian Countries, which will promote bi-regional coordination of Science &Technology (S&T) cooperation, including priority setting and definition of S&T cooperation policies. The objectives of CASCADE, as an 18-month supporting action, are to: compile a regional position paper that identifies global challenges and research priorities; map and develop an inventory of national and regional stakeholders related to global challenges; and, raise awareness on research & innovation priorities for fostering cooperation and towards building mutual understanding on how to address common global societal challenges. CASCADE targets & has the participation of all South Asian countries specified in the Call: Afghanistan, Bangladesh, Bhutan, Maldives, Nepal, Pakistan and Sri Lanka. The project comprises five work packages (WP). WP1 will, coordinate the delivery of project outputs, ensure achievement of anticipated outcomes, and develop and manage project infrastructure. WP2 will produce national (Afghanistan, Bangladesh,Bhutan, Maldives, Nepal, Pakistan and Sri Lanka) and regional (Southern Asia) position papers providing a consensus on the key societal challenges in the region linked to Horizon2020. These papers will be used as the basis for WP3: the identification and mapping of key national and regional stakeholders that can influence and address these societal challenges. WP4 will engage these key stakeholders, raise awareness of the potential for EU-Southern Asia cooperation, and stimulate their participation in Horizon 2020. WP5 will use the position papers from WP2 and stakeholder maps from WP3 to compile a policy brief with recommendations to the European Commission on how to promote bi-lateral cooperation with Southern Asia with a view to tackling key societal challenges of mutual interest. WP5 will also promote Southern Asian contacts among major European stakeholders.
Khan A.N.,University of Engineering & Technology, Peshawar
Optical Fiber Technology | Year: 2017
Currently, analytical models are used to compute approximate blocking probabilities in opaque and all-optical WDM networks with the homogeneous link capacities. Existing analytical models can also be extended to opaque WDM networking with heterogeneous link capacities due to the wavelength conversion at each switch node. However, existing analytical models cannot be utilized for all-optical WDM networking with heterogeneous structure of link capacities due to the wavelength continuity constraint and unequal numbers of wavelength channels on different links. In this work, a mathematical model is extended for computing approximate network blocking probabilities in heterogeneous all-optical WDM networks in which the path blocking is dominated by the link along the path with fewer number of wavelength channels. A wavelength assignment scheme is also proposed for dynamic traffic, termed as last-fit-first wavelength assignment, in which a wavelength channel with maximum index is assigned first to a lightpath request. Due to heterogeneous structure of link capacities and the wavelength continuity constraint, the wavelength channels with maximum indexes are utilized for minimum hop routes. Similarly, the wavelength channels with minimum indexes are utilized for multi-hop routes between source and destination pairs. The proposed scheme has lower blocking probability values compared to the existing heuristic for wavelength assignments. Finally, numerical results are computed in different network scenarios which are approximately equal to values obtained from simulations. © 2017 Elsevier Inc.
El-Dessouky H.,Islamic University |
Ahmad J.,University of Engineering & Technology, Peshawar |
Alzarah A.,King Abdulaziz City for Science and Technology
Chemical Engineering Communications | Year: 2016
The main objective of this study is to experimentally evaluate the effect of the air precooler heat transfer area on the effectiveness of a two-stage evaporative air cooler. To the best of our knowledge, this effect has not been studied before. In the experimental unit used, there were three identical heat exchangers to precool the ambient air prior to its flow into the direct evaporative cooling unit. These heat exchangers can work individually or be combined to control the total heat transfer area of the air precooler. In addition, the effectiveness of the two-stage system was measured as a function of the ratio between the mass flow rate of water flowing over the packing and the mass flow rate of the dry air passing through the packing; the effectiveness also depends on the mass flow rate of water flowing into the precoolers. The data obtained showed that there is an optimum value for the air precooler heat transfer area at which the thermal performance of the two-stage evaporative cooler has the maximum value. Moreover, the system effectiveness improved with the rate of flow of water into the first and the second precoolers. Note that the optimum value of the precooler heat transfer area should be determined accurately for each set of design and operating conditions. © 2016, Copyright © Taylor & Francis Group, LLC.
Waqas M.,Quaid-i-Azam University |
Farooq M.,Riphah International University |
Khan M.I.,Quaid-i-Azam University |
Alsaedi A.,King Abdulaziz University |
And 4 more authors.
International Journal of Heat and Mass Transfer | Year: 2016
The present paper addresses magnetohydrodynamics (MHD) flow of micropolar liquid towards nonlinear stretched surface. Analysis is presented with viscous dissipation, Joule heating and convective boundary condition. Characteristics of heat transfer are analyzed with mixed convection phenomenon. Dimensional nonlinear equations are converted into dimensionless expressions by employing suitable transformations. Homotopic procedure is implemented to solve the governing dimensionless problems. Behaviors of several sundry variables on the flow and heat transfer is scrutinized. Skin friction coefficient and local Nusselt number are presented and evaluated. Obtained results are also compared with the available data in the limiting case and good agreement is noted. © 2016 Elsevier Ltd
Arshad M.A.,University of Engineering & Technology, Peshawar
Earthquake Science | Year: 2016
An inversion method was applied to crustal earthquakes dataset to find S-wave attenuation characteristics beneath the Eastern Tohoku region of Japan. Accelerograms from 85 shallow crustal earthquakes up to 25 km depth and magnitude range between 3.5 and 5.5 were analyzed to estimate the seismic quality factor Qs. A homogeneous attenuation model Qs for the wave propagation path was evaluated from spectral amplitudes, at 24 different frequencies between 0.5 and 20 Hz by using generalized inversion technique. To do this, non-parametric attenuation functions were calculated to observe spectral amplitude decay with hypocentral distance. Then, these functions were parameterized to estimate Qs. It was found that in Eastern Tohoku region, the Qs frequency dependence can be approximated with the function 33 f1.22 within a frequency range between 0.5 and 20 Hz. However, the frequency dependence of Qs in the frequency range between 0.5 and 6 Hz is best approximated by Qs (f) = 36 f0.94 showing relatively weaker frequency dependence as compared to the relation Qs (f) = 6 f2.09 for the frequency range between 6 and 15 Hz. These results could be used to estimate source and site parameters for seismic hazard assessment in the region. © 2016, The Author(s).
PubMed | University of Engineering & Technology, Peshawar
Type: | Journal: TheScientificWorldJournal | Year: 2016
For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908mV at the current level of 155A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1F, 5.5V) and rechargeable battery (Nickel-Cadmium, 3.8V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented.