858 research outputs found

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

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    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

    Analytical Investigation of Mobile NFC Adaption with SWOT-AHP Approach: A Case of Italian Telecom

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    The purpose of this study is to appraise the critical factors in near field communication (NFC) adoption process and to utilize findings in order to support launching NFC implementations in Italy, by means of applying a combination of SWOT and AHP approaches. Hence, a set of twenty SWOT factors is identified qualitatively through extended interviews with telecommunication experts as well as exploratory studies on case which are supported by quantitative investigation through pair-wise comparisons matrices as an application of AHP approach. However, this combined methodology enables us to describe NFC adoption process, providing guidance to clarify the critical factors during adoption process. As the first application of joint SWOT and AHP approaches in telecommunication networks, managerial perceptions are promising either for policy makers concerning NFC or further academic researches on NFC application and full scale deployment in market

    Optimization of accurate estimation of single diode solar photovoltaic parameters and extraction of maximum power point under different conditions

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    Introduction. With the snowballing requirement of renewable resources of energy, solar energy has been an area of key concern to the increasing demand for electricity. Solar photovoltaic has gotten a considerable amount of consideration from researchers in recent years. Purpose. For generating nearly realistic curves for the solar cell model it is needed to estimate unknown parameters with utmost precision. The five unknown parameters include diode-ideality factor, shunt-resistance, photon-current, diode dark saturation current, and series-resistance. Novelty. The proposed research method hybridizes flower pollination algorithm with least square method to better estimate the unknown parameters, and produce more realistic curves. Methodology. The proposed method shows many promising results that are more realistic in nature, as compared to other methods. Shunt-resistance and series-resistance are considered and diode constant is not neglected in this approach that previously has been in practice. The values of series-resistance and diode-ideality factor are found using flower pollination algorithm while shunt-resistance, diode dark saturation current and photon-current are found through least square method. Results. The combination of these techniques has achieved better results compared to other techniques. The simulation studies are carried on MATLAB/Simulink.Вступ. З огляду на величезну потребу у відновлюваних енергетичних ресурсах, сонячна енергія стала ключовою сферою розв’язання проблеми зростання попиту на електроенергію. За останні роки сонячна фотоелектрична техніка отримала значну увагу з боку дослідників. Мета. Для створення майже реалістичних кривих для моделі сонячних батарей необхідно оцінити невідомі параметри з максимальною точністю. П'ять невідомих параметрів включають коефіцієнт ідеальності діодів, опір шунту, фотонний струм, струм темного насичення діодів і послідовний опір. Новизна. Запропонований метод дослідження поєднує алгоритм запилення квітів із методом найменших квадратів для кращої оцінки невідомих параметрів та отримання більш реалістичних кривих. Методологія. Запропонований метод демонструє багато перспективних результатів, які є більш реалістичними за своєю природою, порівняно з іншими методами. Розглянуто опір шунта і послідовний опір, і в цьому підході, який раніше застосовувався на практиці, не нехтують постійною діода. Значення послідовного опору та коефіцієнта ідеальності діодів визначаються за допомогою алгоритму запилення квіток, тоді як опір шунту, струм темного насичення діодів і фотонний струм - методом найменших квадратів. Результати. Поєднання цих методів забезпечило кращі результати у порівнянні з іншими методами. Моделювання проводиться на MATLAB/Simulink

    Partial slip effect on heat and mass transfer of MHD peristaltic transport in a porous medium

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    This research looks at the effects of partial slip on heat and mass transfer of peristaltic transport. The magnetohydrodynamic (MHD) flow of viscous fluid in a porous asymmetric channel has been considered. The exact solutions for the stream function, longitudinal pressure gradient, longitudinal velocity, shear stress, temperature and concentration fields are derived by adopting long wavelength and small Reynolds number approximations. The results showed that peristaltic pumping and trapping are reduced with increasing velocity slip parameter. Furthermore, temperature increases with increasing thermal slip parameter. Moreover, the concentration profile decreases with increasing porosity parameter, Schmidt number and concentration slip parameter. Comparisons with published results are found to be in good agreement

    Exposure to NO2 in occupational built environments in urban centre in Lahore

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    Increased economic growth, urbanisation and substantial rise in automobile vehicles has contributed towards the elevated levels of air pollution in major cities in Pakistan. Aone week study was conducted by using passive samplers to assess NO2 concentration in occupational built environments at two most congested and populated sites of Lahore. Both sites were locatedon the busy roads of Lahore. At Site-I the highest concentration was in outdoors followed by corridor and indoor. While at Site II all the sampling location wereindoors and level were comparable to that of outdoor levelsat Site I. The results suggest the likely contribution of ambient sources in exposure to indoor NO2 in educational and other occupational built environments in urban centres

    Managing project scope creep in construction industry

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    Purpose Project scope creep is a nightmare and nearly intolerable task. Most project managers struggle to curtail the expanse and degree of scope creep. This study examines different likely project scope creep factors associated with the construction industry projects. Design/methodology/approach After many brainstorming sessions with construction stakeholders, several project scope creep factors were identified. Then, a detailed survey was executed in big construction projects of the United Arab Emirates (UAE). The data were analyzed using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Findings The results derived and validated five conspicuous factors leading to project scope creep. Respectively, the highest and the lowest impact on project scope appears to be imposed by tasks/specifications and complexity/uncertainty. Practical implications It offers crucial support to the project stakeholders in scrutinizing different factors that stand as hurdles to project success and allows them to seek remedies to resolve them. Originality/value It is among the first study in the region that identifies and validates the factors that hinder construction project success.©2022 Emerald Publishing Limited. This manuscript version is made available under the Creative Commons Attribution–NonCommercial 4.0 International (CC BY–NC 4.0) license, https://creativecommons.org/licenses/by-nc/4.0/fi=vertaisarvioitu|en=peerReviewed

    Exploring cucumber extract for skin rejuvenation

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    This study was designed to develop a topical skin-care cream water in oil (w/o) emulsion of 3% cucumber extracts versus its vehicle (Base) as control and evaluates its effects on skin-melanin, skin erythema, skin moisture, skin sebum and transepidermal water loss (TEWL).  Hydroalcohol.c cucumber (Cucumis sativus) fruit extract was entrapped in the inner aqueous phase of w/o emulsion. Base containing no extract and a formulation containing 3% concentrated extract of C. sativus was formulated. The odour was adjusted with few drops of lemon oil. Both the base and formulation were stored at different storage conditions for a period of 4 weeks to predict their stability. Different stability parameters that is: Physical stability, centrifugation and pH were monitored at different time intervals. Both the base and formulation were applied to the cheeks of 21 healthy human volunteers for a period of 4 weeks. The expected pharmaceutical stability of creams was achieved from 4 weeks in vitro study period. Odour disappeared with passage of time due to volatilization of lemon oil. The base showed insignificant (p > 0.05) effects on all skin parameters except sebum that was not significant, whereas the formulation showed statistically significant (p.0.05) effects on skin sebum secretion. TEWL and erythema was increased while skin melanin and skin hydration level was decreased by formulation. However these effects were statistically insignificant (p > 0.05). The results showed a good stability over 4 weeks of observation period of both base and formulation and the formulation has anti sebum secretion, bleaching and moisturizing effects.Key words: Cucumber extract, melanin, skin moisture, skin sebum, transepidermal water loss (TEWL)

    Measurement of NO<inf>2</inf> indoor and outdoor concentrations in selected public schools of lahore using passive sampler

    Get PDF
    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 NO2 in 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
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