Effect of hot-arid climatic solar energy on monocrystallinephotovoltaic performance in Pakistan

The domestic dwellings in Pakistan have predominantly implemented low-carbon strategies by harvesting solar energy using photo-voltaic (PV) panels as a long-term vision of low-carbon economy. Most of the urban areas in Pakistan stay hot and humid in an entire year. Consistent solar irradiation at higher temperatures is one of the major factors that affect the power generation performance of monocrystalline PV systems pose challenges to performance and degradation issues. Monocrystalline PV module efficiencies are declining and damaging under the continuous exposure to higher surface day-time temperatures in the different parts of the country. MATLAB simulations were performed based on the validated mathematical approach. This paper investigates the hot arid surface temperature impacts on the performance of PV modules during the summer and winter seasons in Pakistan. The investigations are performed examining the comparative output power generating performance of the PV system. This paper also investigates the influence of installations of PV-system in the North, South, East and West regions of Pakistan. It was examined that the northern areas of Pakistan are more suitable for maintaining the long-term durability of the PV system. Investigations are performed for the peak summer and peak winter days. During summer months, cooling strategies have to be implemented to overcome the heating effects whilst reducing degradation effect on installed PV-system

An a posteriori error analysis of a mixed finite element Galerkin approximation to second order linear parabolic problems

In this article, a posteriori error estimates are derived for a mixed finite element Galerkin approximation to second order linear parabolic initial and boundary value problems. Using mixed elliptic reconstruction method, a posteriori error estimates in $L^\infty(L^2)$ and $L^2(L^2)$-norms with optimal order of convergence for the solution as well as its flux are proved for the semidiscrete scheme. Finally, based on backward Euler method, a completely discrete scheme is analyzed and a posteriori bounds are derived, which improves earlier results on a posteriori estimates for mixed parabolic problems

Why physicians and lay people smoke and how can it be reduced?

Objective: The objective of this study was to find out the level of knowledge the physicians and lay people have pertaining to the effect of cigarettes, why certain physicians smoke and what measures could be applied to reduce the rate of smoking. Methods: A questionnaire was administered to the one hundred physicians who smoke, one hundred non-smoking physicians and one hundred lay people who smoke to determine their attitude towards this addition. Subjects were chosen using convenience sampling. The physicians were picked from six hospitals of Karachi. Results: When the smoking physicians were asked what could motivate them to stop smoking, majority of them said that an occurrence of a smoking related illness would. Majority of the physicians who do not smoke felt that individual will was the greatest force keeping them from smoking. When asked how smoking can be reduced in Pakistan, majority of the physicians, both smoking and non-smoking, favoured mass health education. Lay smokers expressed marked ignorance about deleterious effects of cigarette smoke. Like smoking physicians, majority of them said that occurrence of an illness related to smoking would effectively motivate them to stop smoking. CONCLUSION: Based on this survey we conclude that mass health education and enforcement of the ban on smoking in public places will effectively reduce the number of smokers. There is a need to educate physicians and the general public about the cardiac and carcinogenic effects of smoking

Predictive permanent magnet synchronous generator based small-scale wind energy system at dynamic wind speed analysis for residential net-zero energy building

Integration of small-scale wind energy system to residential buildings for a target to achieve net-zero CO2 emissions is a revolutionary step to reduce the dependency on the national grid. In this paper, a predictive 20 kVA permanent magnet synchronous generator (PMSG) based small scale wind turbine is investigated at dynamic wind speed with a sensing control system to manage and monitor the power flow for a supply to a typical residential building. A control system is applied that regulates the power from the wind turbine. Results indicate that the proposed control system maximizes the power efficiency within the system. The maximum power generation capacity of the wind turbine is 20 kWh with 415 VAC and 50 Hz frequency. A storage system of 19.2 kWh that supplies the energy to the load side. The applied control unit improves the energy management and protects the power equipment during the faults. The research is conducted using MATLAB/SIMULINK and mathematical formulations

MODLEACH: A Variant of LEACH for WSNs

Wireless sensor networks are appearing as an emerging need for mankind. Though, Such networks are still in research phase however, they have high potential to be applied in almost every field of life. Lots of research is done and a lot more is awaiting to be standardized. In this work, cluster based routing in wireless sensor networks is studied precisely. Further, we modify one of the most prominent wireless sensor network's routing protocol "LEACH" as modified LEACH (MODLEACH) by introducing \emph{efficient cluster head replacement scheme} and \emph{dual transmitting power levels}. Our modified LEACH, in comparison with LEACH out performs it using metrics of cluster head formation, through put and network life. Afterwards, hard and soft thresholds are implemented on modified LEACH (MODLEACH) that boast the performance even more. Finally a brief performance analysis of LEACH, Modified LEACH (MODLEACH), MODLEACH with hard threshold (MODLEACHHT) and MODLEACH with soft threshold (MODLEACHST) is undertaken considering metrics of throughput, network life and cluster head replacements.Comment: IEEE 8th International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA'13), Compiegne, Franc

Delayed Duodenal Hematoma and Pancreatitis from a Seatbelt Injury

Traumatic duodenal hematoma is a rare condition that is encountered in the paediatric age group following blunt abdominal trauma. It poses both a diagnostic and therapeutic challenge. The main concern is increased morbidity secondary to delayed diagnosis and associated occult injuries to the adjacent structures. Most of these hematomas resolve spontaneously with conservative management, and the prognosis is good. We present a case of a 15-year-old boy who had a delayed presentation of duodenal hematoma and acute pancreatitis, which was treated conservatively with complete resolution

Emergency Intraperitoneal Onlay Mesh Repair of Incarcerated Spigelian Hernia

This report suggests that Spigelian hernia in an emergency setting may be easily and quickly repaired with an intraperitoneal onlay method using composite mesh

Factors influencing the performance parameters of vacuum glazed smart windows to net zero energy buildings

The progression of smart technologies such as vacuum glazed windows are considered a realistic achievement of the net energy zero buildings (NZEBs). From designers to researchers to builders, there has been an increasing concern about understanding the inter-dependencies between the parameters and influencing factors that determine the performance of vacuum glazed smart windows. This research reviews the performance parameters such as thermal transmittance (U value), thermal resistance (R value), solar transmittance (g value), visible light transmittance (tv value) and thermal resistance of residual gas space (Rgas value). These are inter-dependent on factors such as edge seal, support pillar array, low emittance coatings, getters, and effective evacuation process. This research implicates that effective hermetic edge seal provides longevity such as fusion and solder glass edge sealed vacuum glazing could be cost-effective and energy efficient solution. Stainless steel support pillar array is an unavoidable compromise on U value. This review shows that an increase of the size of glass sheet increases support pillar array improving the overall U value. Also, an addition of low emittance coatings enhances U value whilst maintaining tv value. To improve the overall life span of the vacuum glazed smart window, an incorporation of combo-getter that absorb any gases released from the internal glass surfaces in to into the vacuum cavity from the glass surface which prevents degradation of vacuum pressure and provide long term vacuum pressure stability in the vacuum glazed smart window. A recent improvement in the understanding of evacuation process shows that hot-plate surface heat induction of 60˚C improved the vacuum pressure and mitigates the pump-out hole sealing process whilst lessening the temperature induced stresses

Enhancing the renewable energy payback period of a photovoltaic power generation system by water flow cooling

A photovoltaic system which enjoys water flow cooling to enhance the performance is considered, and the impact of water flow rate variation on energy payback period is investigated. The investigation is done by developing a mathematical model to describe the heat transfer and fluid flow. A poly crystalline PV module with the nominal capacity of 150 W that is located in city Tehran, Iran, is chosen as the case study. The results show that by increasing water flow rate, EPBP declines first linearly, from the inlet water flow rate of 0 to 0.015 kg.s-1, and then, EPBP approaches a constant value. When there is no water flow cooling, EPBP is 8.88, while by applying the water flow rate of 0.015 kg.s-1, EPBP reaches 6.26 years. However, only 0.28 further years decrement in EPBP is observed when the inlet water mass flow rate becomes 0.015 kg.s-1. Consequently, an optimum limit for the inlet water mass flow rate could be defined, which is the point the linear trend turns into approaching a constant value. For this case, as indicated, this value is 0.015 kg.s-1