Mehran University of Engineering and Technology informally: Mehran University) , is a public research university located in Jamshoro, Sindh, Pakistan. In its neighborhood is located the Sindh University and Liaquat University of Medical and Health science; it is one of the premier institution of higher learning in the country with a strong focus on industrial management and engineering. Wikipedia.
Khahro S.F.,Beijing Institute of Technology |
Tabbassum K.,Information Technology Center |
Soomro A.M.,Beijing Institute of Technology |
Soomro A.M.,Mehran University of Engineering and Technology |
And 2 more authors.
Energy Conversion and Management | Year: 2014
Pakistan is currently experiencing an acute shortage of energy and urgently needs new sources of affordable energy that could alleviate the misery of the energy starved masses. At present the government is increasing not only the conventional energy sources like hydel and thermal but also focusing on the immense potential of renewable energy sources like; solar, wind, biogas, waste-to-energy etc. The recent economic crisis worldwide, global warming and climate change have also emphasized the need for utilizing economic feasible energy sources having lowest carbon emissions. Wind energy, with its sustainability and low environmental impact, is highly prominent. The aim of this paper is to explore the wind power production prospective of one of the sites in south region of Pakistan. It is worth mentioning here that this type of detailed analysis is hardly done for any location in Pakistan. Wind power densities and frequency distributions of wind speed at four different altitudes along with estimated wind power expected to be generated through commercial wind turbines is calculated. Analysis and comparison of 5 numerical methods is presented in this paper to determine the Weibull scale and shape parameters for the available wind data. The yearly mean wind speed of the considered site is 6.712 m/s and has power density of 310 W/m2 at 80 m height with high power density during April to August (highest in May with wind speed 9.595 m/s and power density 732 W/m2). Economic evaluation, to exemplify feasibility of installing wind turbines, is also done. The estimated cost of per kWh of electricity from wind is calculated as 0.0263 US$/kWh. Thus the candidate site is recommended for some small stand-alone systems as well as for wind farm. © 2013 Elsevier Ltd. All rights reserved.
Ursani A.A.,Mehran University of Engineering and Technology |
Kpalma K.,INSA Rennes |
Lelong C.C.D.,CIRAD - Agricultural Research for Development |
Ronsin J.,INSA Rennes
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2012
A new procedure is proposed for agricultural land-use mapping that addresses a known weakness of classical per-pixel methods in situations involving mixed tree crops. The proposed scheme uses a pair of very-high resolution satellite-borne panchromatic and multispectral images and integrates classification results of two parallel and independent analyses, respectively based on spectral and textural information. The multispectral image is divided into spectrally homogeneous but non-contiguous segments using unsupervised classification. In parallel, the panchromatic image is split into a grid of square blocks on which is performed a texture-driven supervised classification. Finally, the spectral and the textural classifications are fused to generate the land-use map. This method contrasts with object-based methods that sequentially perform image segmentation and classification. Results are evaluated both quantitatively and qualitatively, based on field survey ground-truth data. The quantitative assessment is presented in terms of overall accuracy (from 80% to 100% depending on the area) and Kappa coefficients. Visual comparison of the resulting map with the ground-truth is performed, with the analysis of the binary error maps. Merging spectral and textural classifications results in finer border delimitation and improves the overall classification accuracy of agricultural land-use by 27% as compared to textural classification alone. © 2011 IEEE.
Memon R.A.,Mehran University of Engineering and Technology |
Leung D.Y.C.,University of Hong Kong
Environmental Fluid Mechanics | Year: 2011
This study investigates the impact of building aspect ratio (building-height-to-street-canyon-width-ratio), wind speed and surface and air-temperature difference (Δθs-a) on the heating environment within street canyon. The Reynolds-averaged Navier-Stokes (RANS) and energy transport equations were solved with Renormalization group (RNG) theory version of k-turbulence model. The validation process demonstrated that the model could be trusted for simulating air-temperature and velocity trends. The temperature and velocity patterns were discussed in idealized street canyons of different aspect ratios (0.5-2.0) with varying ambient wind speeds (0.5-1.5 m/s) and Δθs-a (2-8 K). Results show that air-temperatures are directly proportional to bulk Richardson number (Rb) for all but ground heating situation. Conversely, air-temperatures increase significantly across the street canyon with a decrease in ambient wind speed; however, the impact of Δθs-a was negligible. Clearly, ambient wind speed decreases significantly as it passes over higher AR street canyons. Notably, air-temperatures were the highest when the windward wall was heated and the least during ground heating. Conversely, air-temperatures were lower along the windward side but higher within the street canyon when the windward wall was heated. © 2010 The Author(s).
Hashmani A.A.,University of Duisburg - Essen |
Hashmani A.A.,Mehran University of Engineering and Technology |
Erlich I.,University of Duisburg - Essen
International Journal of Electrical Power and Energy Systems | Year: 2012
This paper presents the design of local decentralized power system stabilizer (PSS) controllers, using selected suitable remote signals as supplementary inputs, for a separate better damping of specific inter-area modes, for large-scale power systems. System identification technique is used for deriving lower order state-space models suitable for control design. The lower-order model is identified by probing the network in open loop with low-energy pulses or random signals. The identification technique is then applied to signal responses, generated by time-domain simulations of the large-scale model, to obtain reduced-order model. Lower-order equivalent models, thus obtained, are used to design each local PSS controller separately for each of the inter-area modes of interest. The PSS controller uses only those local and remote input signals in which the assigned single inter-area mode is most observable and is located at a generator which is most effective in controlling that mode. The PSS controller, designed for a particular single inter-area mode, also works mainly in a frequency band given by the natural frequency of the assigned mode. The locations of the local PSS controllers are obtained based on the amplitude gains of the frequency responses of the best-suited measurement to the inputs of all generators in the interconnected system. For the selection of suitable local and supplementary remote input signals, the features or measurements from the whole system are pre-selected first by engineering judgment and then using a clustering feature selection technique. Final selection of local and remote input signals is based on the degree of observability of the considered single mode in them. To provide robust behavior, H ∞ control theory together with an algebraic Riccati equation approach has been applied to design the controllers. The effectiveness of the resulting PSS controllers is demonstrated through digital simulation studies conducted on a sixteen-machine, three-area test power system. © 2012 Elsevier Ltd. All rights reserved.
Memon R.A.,Mehran University of Engineering and Technology |
Leung D.Y.C.,City University of Hong Kong
Journal of Environmental Sciences | Year: 2010
This study investigated the impact of important environmental variables (i.e., wind speed, solar radiation and cloud cover) on urban heating. Meteorological parameters for fifteen years (from 1990 to 2005), collected at a well developed and densely populated commercial area (Tsim Sha Tsui, Hong Kong), were analyzed in details. Urban heat island intensity (UHII), a well known indicator of urban heating, has been determined as the spatially averaged air-temperature difference between Tsim Sha Tsui and Ta Kwu Ling (a thinly populated rural area with lush vegetation). Results showed that the UHII and cloud cover have increased by around 9.3% and 4%, respectively, whereas the wind speed and solar radiation have decreased by around 24% and 8.5%, respectively. The month of December experienced the highest UHII (10.2°C) but the lowest wind speed (2.6 m/sec) and cloud cover (3.8 oktas). Conversely, the month of April observed the highest increases in the UHII (over 100%) and the highest decreases in wind speed (over 40 %) over fifteen years. Notably, the increases in the UHII and reductions in the wind speed were the highest during the night-time and early morning. Conversely, the intensity of solar radiation reduced while the intensity of urban cool island (UCII) increased during solar noon-time. Results demonstrated strong negative correlation between the UHII and wind speed (coefficient of determination, R2 = 0.8) but no negative correlation between UCII and solar radiation attenuation. A possible negative correlation between UHII and cloud cover was investigated but could not be substantiated. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.