Plastic waste recycling

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Joint Resource Optimization for Multicell Networks with Wireless Energy Harvesting Relays

This paper first considers a multicell network deployment where the base station (BS) of each cell communicates with its cell-edge user with the assistance of an amplify-and-forward (AF) relay node. Equipped with a power splitter and a wireless energy harvester, the self-sustaining relay scavenges radio frequency (RF) energy from the received signals to process and forward the information. Our aim is to develop a resource allocation scheme that jointly optimizes (i) BS transmit powers, (ii) received power splitting factors for energy harvesting and information processing at the relays, and (iii) relay transmit powers. In the face of strong intercell interference and limited radio resources, we formulate three highly-nonconvex problems with the objectives of sum-rate maximization, max-min throughput fairness and sum-power minimization. To solve such challenging problems, we propose to apply the successive convex approximation (SCA) approach and devise iterative algorithms based on geometric programming and difference-of-convex-functions programming. The proposed algorithms transform the nonconvex problems into a sequence of convex problems, each of which is solved very efficiently by the interior-point method. We prove that our algorithms converge to the locally optimal solutions that satisfy the Karush-Kuhn-Tucker conditions of the original nonconvex problems. We then extend our results to the case of decode-and-forward (DF) relaying with variable timeslot durations. We show that our resource allocation solutions in this case offer better throughput than that of the AF counterpart with equal timeslot durations, albeit at a higher computational complexity. Numerical results confirm that the proposed joint optimization solutions substantially improve the network performance, compared with cases where the radio resource parameters are individually optimized

Measurement of NO2 indoor and outdoor concentrations in selected public schools of Lahore using passive sampler

Higher levels of NO2 are a danger to human health especially for children. A seven day study was carried to find out the ambient concentrations of NO2in 27 schools of Lahore with the help of passive samplers. In each school three sites were selected, viz: laboratory, corridor and outdoors. After 7 days exposure the tubes were subjected to spectrophotometric analysis. Results showed that the maximum values measured in laboratory, outdoor and corridors were 376µg/m3 , 222µg/m3 and 77µg/m3 . Minimum values for laboratory, outdoor and corridors were 10µg/m3 , 20µg/m3 and 8µg/m3 . Factors affecting these values were laboratory activities and proximity to main roads. These values were significantly higher than the standard values defined by EPA. Therefore children in schools were at risk of developing health complications

NDM-557: COMPUTATIONAL MODELING OF HILL EFFECTS ON TORNADO LIKE VORTEX

Tornado is a complex flow structure, where high swirling flow closer to the ground converges to the center and then moves upward. As a result, it creates a high suction pressure at the ground near the center of the tornado. The main objective of this study is to analyse the impact over flow structure and ground pressure by implementing topographical changes. For the present study a one-celled tornado replicating a real EF-2 scale has been chosen. Previous study suggests that suction ground pressure is highest at the tornado core center, also it changes more sharply near the core center. As a result, the authors decided to raise the surface in the form of a hill at the tornado core center. In this study, two different types of hill based on their slope are implemented for analysing the impact of two different types of topographical changes. It has obtained that as the slope becomes steeper the peak speed up value increases. Also, unlike the synoptic flow case, maximum speed up does not occur at the crest of the hill. Presence of the hill hardly has any impact on the overall pressure distribution at the ground

NDM-558: COMPUTATIONAL MODELING OF TORNADIC LOAD ON A TALL BUILDING

Numerical simulations are carried out to analyse the impact of tornadic load on a tall building. For the present study a one-celled tornado replicating a real EF-2 scale has adopted. A standard tall building based on the Commonwealth Advisory Aeronautical Research Council (CAARC) is used. For detail analysis, the tornado is placed in three different locations with respect to the center of the building. These locations are at the tornado center, at the core radii and outside core radii. As the building has rectangular cross section (plan wise), two different orientation of the building with respect to the center of the buildings are considered. Irrespective of the orientation of the building, higher suction obtains when the center of the building coincides with the center of the tornado and it started to decrease as the tornado center moves away from the building center. This happens due to the ground pressure distribution which dominates the overall pressure distribution along the faces of the building. After comparing the pressure distribution on the roof it obtains that, suction is higher for short building than tall building