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Quetta, Pakistan

Ghumman A.R.,UET | Ghumman A.R.,Qassim University
Environmental Monitoring and Assessment | Year: 2011

Water quality of rivers, natural lakes, and reservoirs in developing countries is being degraded because of the contaminated inflows. There is a serious need for appropriate water quality monitoring for future planning and management of clean water resources. Quality of water in Rawal Lake Pakistan has been investigated in this paper. Flows from the upstream of Rawal Lake and its surrounding villages are highly polluted. Lake water quality parameters like pH, turbidity, alkalinity, calcium, nitrite, sulfate, biological oxygen dissolved, dissolved oxygen, chloride, total dissolved solids (TDS), and coliforms were investigated. Samples of water from different locations of Korang River were collected and tested. Most of the data was collected by field sampling and field visits. However, long-term information was taken from different departments. Statistical parameters (standard deviation, maximum, minimum, mean, mode, kurtosis, skew, and Euclidean distance) of variables were determined. A distinct parameter based on the difference of the maximum value the variable and maximum allowable value of that variable defined by World Health Organization was used for analysis. Grouping and clustering of elements was made on the basis of this parameter. Trend of increasing or decreasing of values of variables over a long time was also taken into account for grouping the variables. It was concluded that the concentration of seven contaminants was higher as compared to the permissible limits under environmental standards. These variables need immediate attention. The environmentally bad conditions of Rawal Lake can only be rectified by appropriate lake environmental supervision, watershed management, and implementation of environmental legislation. © 2010 Springer Science+Business Media B.V. Source

Mahfouz F.M.,UET
International Journal of Thermal Sciences | Year: 2011

Buoyancy driven flow and associated heat convection in an elliptical enclosure has been investigated. The enclosure which is the space between two horizontal concentric confocal elliptic tubes is heated through its inner tube surface which is maintained at either uniform temperature or uniform heat flux. The induced buoyancy driven flow and the associated heat convection are predicted at different enclosure orientations. The full governing equations in terms of vorticity, stream function and temperature are solved numerically using Fourier Spectral Method. Beside Rayleigh and Prandtl numbers the heat convection process in the enclosure depends on the geometry of the enclosure and the angle of inclination with respect to gravity vector. The geometry of the enclosure is represented in terms of major axes ratio and axis ratio of inner tube. The study considered a moderate range of Rayleigh numbers between 5 × 10 3 and 1 × 10 5 while Prandtl number is fixed at 0.7. The inner tube axis ratio is considered between 0 and 1 while the ratio between the two major axes is considered up to 3. The angle of inclination of the minor axes with respect to gravity vector is varied from 0 to 90°. The results for local and average Nusselt numbers as well as temperature distribution are obtained and discussed together with the details of both flow and thermal fields. For isothermal heating conditions, the study has shown an optimum value for major axes ratio that minimizes the rate of heat transfer in the enclosure. While in case of heating at uniform heat flux the study revealed existence of major axes ratio at which the mean temperature of the inner wall is maximum. Another aspect of this paper is the prediction of global flow circulation around the inner tube in case of asymmetrical orientation of the enclosure with respect to the gravity vector. © 2011 Elsevier Masson SAS. All rights reserved. Source

Munir A.,Quaid-i-Azam University | Shahzad A.,UET | Khan M.,Quaid-i-Azam University
PLoS ONE | Year: 2014

The major focus of this article is to analyze the forced convective heat transfer in a steady boundary layer flow of Sisko fluid over a nonlinear stretching sheet. Two cases are studied, namely (i) the sheet with variable temperature (PST case) and (ii) the sheet with variable heat flux (PHF case). The heat transfer aspects are investigated for both integer and non-integer values of the power-law index. The governing partial differential equations are reduced to a system of nonlinear ordinary differential equations using appropriate similarity variables and solved numerically. The numerical results are obtained by the shooting method using adaptive Runge Kutta method with Broyden's method in the domain [0,∞). The numerical results for the temperature field are found to be strongly dependent upon the power-law index, stretching parameter, wall temperature parameter, material parameter of the Sisko fluid and Prandtl number. In addition, the local Nusselt number versus wall temperature parameter is also graphed and tabulated for different values of pertaining parameters. Further, numerical results are validated by comparison with exact solutions as well as previously published results in the literature. © 2014 Munir et al. Source

Ullah S.,UET
Proceedings of 2016 13th International Bhurban Conference on Applied Sciences and Technology, IBCAST 2016 | Year: 2016

In this paper, the polarization sensitive characteristics of Electromagnetic Bandgap (EBG) structures are discussed. EBG structures are used as a ground plane in modern antenna design due to their high-impedance and in-phase reflection behavior. Some wireless communication applications (such as satellite) are polarization sensitive and require a great care in designing the ground planes of the antennas being used. If a traditional Perfect Electric Conductor (PEC) ground plane is used then communication link will fail due to the polarization inverting properties of it. In this work a special type of EBG ground plane is designed for applications which use circularly polarized antennas for communication purposes. A phase difference of approximately 180 degrees, between the orthogonal (x and y) components of the electric fields of the incident electromagnetic wave, is obtained by using a cross-sheet via in the proposed EBG. This phase condition is the basic requirement for EBG structures employed in Circular Polarization (CP) applications. The phase difference preserves the sense of polarization of the incident waves being reflected from the proposed ground plane. The relative phase angle of the x and y polarized components of the E-fields is adjusted by varying the corresponding length of the x and y-arms of via. This parametric analysis is done till the phase-difference is fine-tuned to 180 degrees. The proposed EBG structure can be used in clockwise and counter clockwise circularly polarized, low-profile antenna designs. The electromagnetic analysis of the structure is carried out using Finite Difference Time Domain (FDTD) method. © 2016 IEEE. Source

News Article | March 15, 2016
Site: http://cleantechnica.com

This country’s utilities are addressing disruptive changes taking place in a number of different ways. Some adhere to more standard business models, moving at a painstaking snail’s pace in order to make any kind of change, no matter how timely the alterations. Then there are others who are embracing innovation, looking at the universe of changing technologies as an open door to new business opportunities. Include Washington-based Avista Utilities on the list of utilities embracing the disruptive technologies which are presently happening across the industry, such as battery storage technology, and leveraging it for a new business model called “economies of scope” – a model Avista believes is the future of the utility business. To this end, Spokane, Washington-based Avista Utilities Corporation’s Energy Storage Project in Pullman, Washington provides a solid example of innovation for the future of electricity distribution. The storage project addresses a large challenge facing today’s energy industry: integrating power generated from intermittent, renewable resources, such as wind and solar, into the electrical grid. The project is also testing better ways to improve power system reliability. Avista’s vice president of energy delivery Heather Rosentrater, who oversees this project, recalls what drove her to this utility was finding a business culture which took advantage of innovation. “We really do have a culture of innovation here,” she said. “Employees are encouraged to leverage new technology as it advances.” Rosenstrater adds Avista customers cover a broad spectrum of preferences, ranging from those who want dependability and simply want to pay their bill to individuals wanting to own their electricity generation and sell that generation to their neighbors. “It’s really looking at preferences and recognizing that there isn’t going to be one-size-fits-all for our customers.” she says. The utility’s business vision includes assessing how potentially disruptive distributed energy technologies connecting to the grid can create opportunities. Then comes innovation.  “One of the ways we are particularly focused on is through economies of scope,” observes Rosenstrater. “That means using those assets like the storage and the battery project that we have, trying to leverage it every day.” While most utility customers may expect a reliable energy system, including one featuring renewable energies, most know little about the management of such a distribution infrastructure. “Electric energy—including power from renewable resources—must be used as soon as it is generated. So if the wind isn’t blowing or the sun isn’t shining during times when people need the most energy, it is not always possible to meet customer demand.” Avista’s Energy Storage project is testing new batteries that can store power when it’s abundant and distribute electricity when it’s needed. A successful platform provides reliable energy regardless of weather patterns — a standard criticism of renewable alternatives. That is, until energy storage is added to the puzzle of integrating renewable resources into the electric grid. Last April, Washington Governor Jay Inslee, Senator Maria Cantwell, and Congresswoman Cathy McMorris Rodgers joined Avista executives in Pullman to energize and dedicate the utility’s Energy Storage Project. The event marked a significant milestone as Avista commenced testing its new battery storage system. Over an 18-month period, Avista, working with Schweitzer Engineering Laboratories, will test this large-scale energy storage system. Avista’s goal is to explore how its 1 MW, 3.2 MWh large-scale battery system energy storage can help its electrical grid become more flexible and reliable by integrating power from intermittent renewable sources. The system has the capacity to power 750 homes for 3.2 hours. The $7 million project was funded by a $3.2 million grant from Governor Inslee and the Washington State Department of Commerce’s Clean Energy Fund and another $3.8 million in Avista matching funds. According to Clean Technology Business Review (CTBR), UniEnergy Technologies (UET) and Avista today announced the selection of Northern Power Systems to deliver advanced power conversion for the largest capacity flow battery installed in North America. Situated near Pullman, Washington, near Washington State University and Schweitzer Engineering Laboratories, the battery started operations last April. UniEnergy Technologies manufactured the battery. The UET system is an advanced vanadium flow battery, which uses Pacific Northwest National Laboratories technology. Avista has until now used the system for load shifting, frequency regulation, and voltage regulation on the distribution circuit in Pullman. CTBR reports that the addition of the NPS converters will allow “the UET system to support Avista’s customer Schweitzer Engineering Laboratories to provide power supply without interruptions, black start and four-cycle ride-through to SEL’s manufacturing plant.” This electricity storage infrastructure appears to be operating successfully. If so, we can anticipate other utilities to be analyzing the results of this project for other renewable energy projects. Images via Avista    Get CleanTechnica’s 1st (completely free) electric car report → “Electric Cars: What Early Adopters & First Followers Want.”   Come attend CleanTechnica’s 1st “Cleantech Revolution Tour” event → in Berlin, Germany, April 9–10.   Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.  

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