The NED University of Engineering and Technology, is a public research university located in the urban area of Karachi, Sindh, Pakistan. It is one of the oldest institution of higher learning in Pakistan and is noted for its strong emphasis on higher learning in science and technology.Founded in 1922 as a technical project to provide training to civil engineers working in building the Sukkur Barrage, the university came to its modern form after being established by the British government. The university is named for its benefactor, donor, and philanthropist, Nadirshaw Eduljee Dinshaw by the government. Besides its focus on science and engineering programmes, the university also offers wide range of academic programmes in philosophy, humanities, and fine arts for undergraduate, post-graduate, and doctoral studies. The university is also a member of Association of Commonwealth Universities of the United Kingdom.Primarily, its financial endowment and the scientific research is directed towards the development of the engineering, management, natural, and medical science. Organized into six science faculties as well as various associated research institutions affiliated with the university in Karachi. Wikipedia.
Razi A.,University College London |
Razi A.,NED University of Engineering and Technology |
Kahan J.,University College London |
Rees G.,University College London |
Friston K.J.,University College London
NeuroImage | Year: 2015
Recently, there has been a lot of interest in characterising the connectivity of resting state brain networks. Most of the literature uses functional connectivity to examine these intrinsic brain networks. Functional connectivity has well documented limitations because of its inherent inability to identify causal interactions. Dynamic causal modelling (DCM) is a framework that allows for the identification of the causal (directed) connections among neuronal systems - known as effective connectivity. This technical note addresses the validity of a recently proposed DCM for resting state fMRI - as measured in terms of their complex cross spectral density - referred to as spectral DCM. Spectral DCM differs from (the alternative) stochastic DCM by parameterising neuronal fluctuations using scale free (i.e., power law) forms, rendering the stochastic model of neuronal activity deterministic. Spectral DCM not only furnishes an efficient estimation of model parameters but also enables the detection of group differences in effective connectivity, the form and amplitude of the neuronal fluctuations or both. We compare and contrast spectral and stochastic DCM models with endogenous fluctuations or state noise on hidden states. We used simulated data to first establish the face validity of both schemes and show that they can recover the model (and its parameters) that generated the data. We then used Monte Carlo simulations to assess the accuracy of both schemes in terms of their root mean square error. We also simulated group differences and compared the ability of spectral and stochastic DCMs to identify these differences. We show that spectral DCM was not only more accurate but also more sensitive to group differences. Finally, we performed a comparative evaluation using real resting state fMRI data (from an open access resource) to study the functional integration within default mode network using spectral and stochastic DCMs. © 2014 The Authors.
Friston K.J.,University College London |
Litvak V.,University College London |
Oswal A.,University College London |
Razi A.,University College London |
And 6 more authors.
NeuroImage | Year: 2016
This technical note describes some Bayesian procedures for the analysis of group studies that use nonlinear models at the first (within-subject) level - e.g., dynamic causal models - and linear models at subsequent (between-subject) levels. Its focus is on using Bayesian model reduction to finesse the inversion of multiple models of a single dataset or a single (hierarchical or empirical Bayes) model of multiple datasets. These applications of Bayesian model reduction allow one to consider parametric random effects and make inferences about group effects very efficiently (in a few seconds). We provide the relatively straightforward theoretical background to these procedures and illustrate their application using a worked example. This example uses a simulated mismatch negativity study of schizophrenia. We illustrate the robustness of Bayesian model reduction to violations of the (commonly used) Laplace assumption in dynamic causal modelling and show how its recursive application can facilitate both classical and Bayesian inference about group differences. Finally, we consider the application of these empirical Bayesian procedures to classification and prediction. © 2015 The Authors.
Khalid A.,NED University of Engineering and Technology |
Junaidi H.,Smith College
Renewable Energy | Year: 2013
This study assess the feasibility of photovoltaic based power plant; for this purpose best site for the location of the project is determined by comparing monthly average daily global solar radiation data of eight Pakistani cities and Quetta city is chosen for the 10 MW plant. RETScreen simulation of the power plant shows that about 23.206 GWh of electricity can be generated in a year if one axis tracking method is employed. At a total cost of $50 m, 50% debt ratio, 9% discount rate the proposed PV plant generates electricity at a rate of $0.157/kWh. The investigation shows that presently the PV based electricity is about 30.8% more expensive as compared to grid supplied electricity. Emission analysis demonstrated that the proposed PV power plant avoided carbon dioxide production by 17,938 tons/year. The analysis shows that presently the proposed PV power plant is not feasible if only economic factors are considered. Sensitivity analysis demonstrates that if total installed cost of the plant is about $35 m then the cost of power from photovoltaic plant will be equal to grid supplied electric power without any subsidy. © 2012 Elsevier Ltd.
Khan A.-U.-R.,NED University of Engineering and Technology
MATEC Web of Conferences | Year: 2017
Reinforced concretes structures located at or near the coast line needs to be repaired more frequently when compared to structures located elsewhere. This study is continuation of previous studies carried out at the Department of Civil Engineering, NED University of Engineering and Technology, Karachi, Pakistan to study the performance of concrete made up of cements blended by pozzolonic materials. Different pozzolanic materials (blast furnace slag, fly ash and silica fume) were used in the study. Tests conducted during the study to compare the performance of samples cast from concrete of different mix designs were Compressive Strength Test (ASTM C 39), Flexural Strength Test (ASTM C 293), Rapid Migration Test (NT Build 492), Absorptivity of the oven-dried samples (ASTM C 642) and Half Cell Potential (ASTM C 876). Use of cements blended with pozzolanic materials, used during the study, proved to be effective in enhancing the performance of the concrete exposed to marine environment. Use of pozzolans in concrete not only provides a sustainable and feasible solution to the durability problems in coastal areas, it also helps in conservation of natural resources and reduction of pollution and energy leading to a green environment. © The Authors, published by EDP Sciences, 2017.
Rafi M.M.,NED University of Engineering and Technology |
Nadjai A.,University of Ulsters Fire Facility
ACI Materials Journal | Year: 2011
Fiber-reinforced polymer (FRP) bars are made of innovative materials and the establishment of the fire resistance of FRP reinforced concrete (RC) is necessary for their widespread application. Experimental behaviors of carbon FRP (CFRP) and hybrid (steelCFRP) bar RC beams at elevated temperatures were investigated in this study. Data are presented from fire tests of six simply supported beams that were fabricated using normalweight concrete. The effect of varying concrete cover and reinforcing bar arrangement was studied. The beams were tested in a floor furnace and carried a service load of 40% of their ambient temperature load capacity. Nonlinear temperature distribution across the cross section was found. This caused additional beam curvature and stress that is known as eigen-stress. At temperatures beyond the glass transition temperature of the polymer resin, the FRP bars debondedfrom the concrete and behaved as tie rods if anchored at the ends. Consequently, the FRP RC beam resists thermomechanical loads by arch action. On the other hand, the thermal behaviors of hybrid beams were a combination of arch and beam action. Failure of a beam was typically initiated by reinforcing bar slip due to anchorage failure. All six beams failed in flexure, which was also the intended failure mode at ambient temperature. Hybrid bar reinforced beams were more ductile compared to FRP RC beams. The CFRP bar reinforced beams showed better strength and stiffness characteristics compared to the hybrid beams. Copyright © 2011, American Concrete Institute. All rights reserved,.
Zuberi M.J.S.,Middle East Technical University |
Ali S.F.,NED University of Engineering and Technology
Renewable and Sustainable Energy Reviews | Year: 2015
Landfills all around the world are one of the major sources that contribute towards global warming and climate change. Although landfilling should be prioritized last in the waste management hierarchy due to highest greenhouse gas emissions as compared to other waste management systems it is still very common around the world. In this study, methane emissions are estimated by applying First Order Decay model to landfills in Pakistan over the latest data available by Pakistan Environmental Protection Agency. Results demonstrate that nearly 14.18 Gg of methane is emitted from the landfills in Pakistan each year. By combusting this methane in the form of biogas collected from the landfills as a waste management scheme we can reduce greenhouse effect up to ∼88%. Same percentage is observed when we apply the similar analysis over the potentially improved practice. Also, Pakistan is facing severe economic crises due to continuous increasing gap between energy demand and supply. Demand is increasing exponentially while supply is observed to remain constant over the last few years due to frozen capacity in spite of having significant renewable/alternate energy resources. Current electricity shortfall has reached up to 6000 MW. Present operational landfills in Pakistan can only contribute up to ∼0.1% to cater the total deficit which does not make any significant difference but if 75% of the total waste generated today is collected and 50% of it landfilled then Pakistan has the potential to produce ∼83.17 MW of power that can contribute up to 1.4% to overcome the current power shortage. The outcomes of this paper may also be applicable to other developing countries having similar resources. © 2014 Elsevier Ltd. All rights reserved.
Chen Z.C.,Concordia University at Montréal |
Khan M.A.,NED University of Engineering and Technology
International Journal of Advanced Manufacturing Technology | Year: 2014
With the development of a new function of computer numerical control controllers, nonuniform rational B-spline (NURBS) interpolation, NURBS tool path generation for sculptured surface machining is under extensive research. The common procedures of the current NURBS tool path planning methods are as follows: first, to find a group of cutter contact points on a sculptured surface; second, to calculate their corresponding cutter locations (CLs); then, to fit a NURBS tool path to the CLs within a prescribed tolerance; and finally, to inspect the tool path for possible gouge by the tool and delete the invalid path segments, if any. However, the NURBS tool path has the following problems: (a) although it passes through the discrete CLs of the theoretical CL path, the deviation along the two paths could be larger than the tolerance; (b) its parameter is not the arc length of the path; and (c) it is difficult to detect gouge along the NURBS path and to remove the invalid segments from it. Consequently, NURBS tool paths generated with the current methods of commercial computer-aided design/computer-aided manufacturing (CAD/CAM) software cannot be used to make smooth and accurate surfaces. To address these problems, this work proposes a new approach to generating arc length parameterized NURBS tool paths with high accuracy in terms of the theoretical CL paths and without gouge and interference. Two practical examples in this work clearly demonstrate the feasibility of this approach and the advantages of the generated NURBS tool paths. Therefore, this approach can be implemented into the CAD/CAM software to promote NURBS machining in industry. © 2013 Springer-Verlag London.
Friston K.J.,University College London |
Kahan J.,University College London |
Biswal B.,University College London |
Razi A.,University College London |
Razi A.,NED University of Engineering and Technology
NeuroImage | Year: 2014
This technical note introduces a dynamic causal model (DCM) for resting state fMRI time series based upon observed functional connectivity-as measured by the cross spectra among different brain regions. This DCM is based upon a deterministic model that generates predicted crossed spectra from a biophysically plausible model of coupled neuronal fluctuations in a distributed neuronal network or graph. Effectively, the resulting scheme finds the best effective connectivity among hidden neuronal states that explains the observed functional connectivity among haemodynamic responses. This is because the cross spectra contain all the information about (second order) statistical dependencies among regional dynamics. In this note, we focus on describing the model, its relationship to existing measures of directed and undirected functional connectivity and establishing its face validity using simulations. In subsequent papers, we will evaluate its construct validity in relation to stochastic DCM and its predictive validity in Parkinson's and Huntington's disease. © 2013 The Authors.
Ismail A.,NED University of Engineering and Technology
Environment and Urbanization | Year: 2011
This paper describes how the Technical Training Resource Centre (TTRC) was set up by a young trainee of the Orangi Pilot Project-Research and Training Institute (OPP-RTI) to support better quality housing and infrastructure provision in the kaatchi abadis (informal settlements) of Karachi. The centre's work includes technical advice for constructing or extending houses and schools, training in construction for those with diplomas in civil engineering and architecture, and training for young people to undertake neighbourhood-level documentation and mapping (this is needed for planning upgrading and for negotiating with government authorities for infrastructure and tenure). The paper also discusses the difficulties that the TTRC faced, including generating sufficient funding to cover its costs. © 2011 International Institute for Environment and Development (IIED).
Uddin N.,NED University of Engineering and Technology |
Neumann S.O.,University of Stuttgart |
Weigand B.,University of Stuttgart
International Journal of Heat and Mass Transfer | Year: 2013
The complex flow field of an impinging jet is investigated to understand the dynamics of vortical structures on heat transfer. The prediction of heat transfer by a turbulent impinging jet at small jet-to-wall distances is a challenging problem in CFD. In this study the flow and heat transfer characteristics of an orthogonally impinging cold jet on a heated plate has been investigated by large eddy simulations using structured grids. The LES simulations are performed with a dynamic Smagorinsky model in the finite volume based code FASTEST, using a second-order-accurate discretisation schemes for space and time. The investigations are performed at Reynolds numbers of 13,000 and 23,000 based on jet's diameter and bulk velocity. The dimensionless jet's outlet-to-target wall distance is two. The LES data help to understand the nature of turbulence in the stagnation zone and in the developing wall jet. Simulations help in understanding the reason of occurrence of second peak in the radial distribution of Nusselt number at the target wall. The dynamics of coherent structures and their influence on the heat transfer is also explored. © 2012 Elsevier Ltd. All rights reserved.