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The problem of energy security, increasing prices of energy, the aspect of environmental pollution and depletion of the known fuel reserves in future have created a scope for utilization of renewable resources. Increasing prices of fossil fuels and costs associated with emissions may affect the economy of a country severely. Similarly, fossil fuels although produce useful energy, are responsible for production of harmful emissions like CO 2 , SO x , NO x etc. These dangerous emissions are andoi:10.11648/j.jenr.s.2016050101.12 fatcat:6ppqpdksjrdc5c7j5jpywfeaha
more »... te threat to human health on our plannet. The obvious choice available is to use renewable energy, which can play a critical role to mitigate these emissions. In this article, hazardous environmental effect of fossil fuels is discussed. The status of existing renewable energy technologies especially wind and solar energy and their future growth trend is presented in this article. In this article a focused literature review on research articles discussing the environmental impact of replacement of fossil fuel energy technologies with renewable technologies, with goals to prove that if fossil fuel energy is replaced by renewable technologies can be a solution to hazardous emissions. Last part of the article provides directions for renewable energy policies of a country, which could help to increase the renewable energy mix in the traditional energy production.
Ahmed S-(1990) Library Muqtadra Quamizuban. An introduction.Pakistan Library Bulletin vol.21(3-4) ... Ahmed Mirza Jamil, proprietor of Elite publishers (Karachi) saw the Chinese character type set in Singapore in 1979 and got inspiration that same software should be created in Urdu. ...doi:10.5281/zenodo.3408225 fatcat:vo2iuvmt6va7zhyw73llgkyw3a
Hot areas of the world receive a high amount of solar radiation. As a result, buildings in those areas consume more energy to maintain a comfortable climate for their inhabitants. In an effort to design net-zero energy building in hot climates, PV possesses the unique advantage of generating electrical energy while protecting the building from solar irradiance. In this work, to form a net-zero energy building (NZEB), renewable resources such as solar and wind available onsite for an existingdoi:10.3390/en11061391 fatcat:43jppmx3kjhhbigjpscwewdaoi
more »... lding have been analyzed in a hot climate location. PV and wind turbines in various configurations are studied to form a NZEB, where PV-only systems offer better performance than Hybrid PV Wind systems, based on net present cost (NPC). The self-shading losses in PV placed on rooftop areas are analyzed by placing parallel arrays of PV modules at various distances in between them. The effect on building cooling load by rooftop PV panels as shading devices is investigated. Furthermore, self-shading losses of PV are compared by the savings in cooling loads using PV as shading. In the case study, 12.3% saving in the cooling load of the building is observed when the building rooftop is completed shaded by PV panels; annual cooling load decreased from 3.417 GWh to 2.996 GWh, while only 1.04% shaded losses are observed for fully shaded (FS) buildings compared to those with no shading (NS), as PV generation decreases from 594.39 kWh/m 2 to 588.21 kWh/m 2 . The net present cost of the project has been decreased from US$4.77 million to US$4.41 million by simply covering the rooftop completely with PV panels, for a net-zero energy building. Energies 2018, 11, 1391 2 of 20 the European Directive 2020  , and national directives such as Vision 2030 of Saudi Arabia [8, 9]. The Paris Accord seeks to limit the increase in global average temperatures to 1.5 • C in 2030, and to achieve net-zero emissions by 2070. The European Union directive focuses on buildings, targeting 20% onsite energy generation, 20% more energy efficiency, and 20% less greenhouse gas emissions from all buildings by 2020. Saudi Arabia announced a plan under Vision 2030 to create a sustainable city, Neom, by the Red Sea on the border of Jordon in Tabuk province. Saudi Arabia also plans to generate 9.5 GW of renewable energy by 2023 [10, 11] . In recent years, renewable energy resources are becoming more economically feasible through the development of new technologies. In the past one year, 157 GW of renewable power systems have been installed at a cost of 279.8 billion US$, while 70 GW of fossil fuel energy systems have been decommissioned. China installed an astonishing 53 GW of solar energy systems at a cost of 86.5 billion US$  . Even the Middle East countries such as UAE and Egypt have spent 2.2 and 2.6 billion US$ respectively on solar energy plants. Currently, photovoltaic systems lead the energy production of renewable energy resources in the world  . Saudi Arabia awarded a 300 MW project to a ACWA Power, a private investor, in February 2018, with an initial capital cost of 300 million US$ ; in March 2018, KSA signed a memorandum with Softbank Group Crop to develop a 200 GW solar plant in multiple phases, with an enormous investment of 200 billion US$ . A lot of research is going on to increase the efficiency of renewable energy resources [15,16]. The research on PV was started analytically in 1950s. Now the dream is to print high energy efficient solar panels on flexible polyethylene terephthalate (PET) substrate, using printed electronics technologies at room temperature and in atmospheric pressure, which can last 25 years [17,18] and retain their efficiencies. The efficiencies of crystalline PV, III-V cell PV, and thin film PV cells have increased to 27.6% , 33.3%  and 21.7%  respectively. Since 2005, PV cell efficiencies have increased at a good rate, as presented by the NREL efficiency chart  and review articles [23,24]. PV and Wind energy system prices are decreasing, and producers are finding it difficult to deliver orders on time. This cost is declining as new competitors from Asia have entered this market. The price of solar panels has decreased by 77% from 2010 to 2017    . The cost of solar energy systems comprises the system design, panels, inverters, and skilled labor cost. New designs in wind energy with bigger turbines are decreasing technology prices, as these machines have higher power coefficients, which means that they can convert more wind energy into electrical energy. Innovative designs have reduced the use of steel in towers, and methods for making a floating tower for off-grid turbines to place them in deep water are currently in research  . The Middle East has abundant renewable resources [10, 28, 29] , and these countries should transform from fossil to renewable. The Kingdom of Saudi Arabia (KSA) is the largest oil exporting country, but huge domestic energy requirements are halting its economic growth  . The load profile of Saudi Arabia is unique, as peak load in summers is two times that of winter, because of huge cooling loads of buildings [31, 32] . The country has very hot and dry weather  . The KSA government has increased electricity prices by 260% from 0.008 US$/kWh. The solution to KSA's load problems is to curtail building load through the use of onsite renewable resources for buildings. Net-zero energy building (NZEB) can be achieved by generating electrical energy onsite, so that the net energy bought from the grid is equal to the energy sold to the grid. Developed countries have already started to design and build net-zero buildings     , in which smart techniques have been adopted to provide good insulation for buildings, reduce the load by effective use control of heating, ventilation, air conditioning (HVAC), and appliances, and to employ renewable energy systems [38, 39] . Modern buildings use both AC and DC energy systems in lighting and appliances to enhance efficiencies and eliminate conversion losses from AC to DC and vice versa [40, 41] . Off-grid energy systems require huge capital investment; during periods in which energy from renewable resources is unavailable, energy is taken from storage devices, whereas in net-zero energy systems, backup depends upon the grid. Off-grid systems require more installed capacity to meet the load, and store energy to use later. Energies 2018, 11, 1391 3 of 20 Energies 2018, 11, 1391 4 of 20 Case Study Analysis KSA has set a target of generating 9.5 GW of electrical energy from renewable energy resources by 2023, and of building a sustainable city by the Red Sea [8, 9] under the kingdom Vision 2030. KSA has already awarded ACWA Power, a private energy developer, a contract to develop the first 300 MW solar power plant, with an initial capital of 300 MUS$ in February 2018  . KSA and Softbank Group Corp signed a memorandum to develop a 200 GW solar plant with an investment of 200 billion US$  . In order to design and develop future renewable energy systems in KSA and fill thousands of jobs, Saudi students have to be well prepared to handle the huge task at hand. Universities are the ideal places to develop and understand the potential and methods of utilization of renewable energy resources and their application on loads such as buildings, to create a net-zero energy building (NZEB), and then spread the knowledge. In this work, the existing building of the College of Engineering, Majmaah University, is taken as a case study. The building of the College of Engineering has five floors and is located at 25.890302 N and 45.35629 E in Majmaah City in Riyadh province, Kingdom of Saudi Arabia (KSA), at a height of 722 m from sea level. The covered area of this building is 4859 m 2 , with parking space at the front and back of the building. The satellite image and building model are shown in Figure 1 . The CoE building working hours are from 8 a.m. to 8 p.m., where the electrical loads include heating and cooling systems, lighting, office equipment, and water heating systems. The annual daily average load is shown in Figure 2b , where a dip occurs at 12 p.m. for lunch break, and another at 2 p.m., when clerical staff leave the building. The annual load in Figure 2a shows the rise of the load with the rise in ambient temperature. The summer holiday months are from mid-June to mid-August; this results in a curtailment of the load. The system has been designed based on summer peak load, as a high load is observed in summer, and the designed system will work well in the winter as well. The KSA government has developed a data collection station to measure renewable resources throughout the kingdom for design and analysis of future renewable energy system projects for the targets set out in Vision 2030. The Majmaah station for renewable sources measurement is located in Majmaah University (MU). This measurement station is a Tier II station with uncertainty in data up to ±5%; the sensors are cleaned twice a week.
Optimistic and sustainable supply of soil available nutrients to crop plants enhances productivity. Integrated nutrient management (INM) approach can improve soil fertility on long term basis. The present study was conducted to determine effects of INM on quantitative and qualitative characters of two Safflower (Carthamus tinctorius L.) cultivars "Thori-78 and Leed-00". Five treatments using different composition of poultry litter, farm yard manure, nitrogen and phosphorous fertilizers withdoi:10.4236/ajps.2017.89148 fatcat:3zsxqvowgzb5jiv6z52fye7zou
more »... mmended dose as a control measure were replicated thrice in randomized complete design. The results of field trial depicted maximum plant height (174.6 cm), number of heads plant −1 (42.67), number of seeds head −1 (59.0), thousand seed weight (42.26 g), biological yield (3089 Kg•ha −1 ) and seed yield (455.2 Kg•ha −1 ) recorded from combined application of FYM @ 2 t•ha −1 and Half (N-P) (soil application) (T 5 ) in Genotype "Leed-00" which was statistically different from all other treatments. Thori-78 also showed increase in yield and yield components under the same treatment (T 5 ) i.e.2 t•ha −1 FYM and Half (N-P).No effect of INM was found on fatty acid composition of safflower cultivars. The correlation coefficients illustrated positive and significant association of seed yield with plant height (0.89), number of heads pod −1 (0.86) and number of seeds head −1 (0.83) as a result of application of selected treatment. These results demonstrated the significance of INM in safflower yield improvement under rainfed conditions.
The increasing penetration of Microgrids (MGs) into existing power systems and "plug and play" capability of Distributed Generators (DGs) causes large overshoots and settling times along with various power quality issues such as voltage and frequency flickers, current harmonics and short current transients. In this context, over the past few years, considerable research has been undertaken to investigate and address the mentioned issues using different control schemes in conjunction with softdoi:10.1109/access.2020.2989133 fatcat:mhraqetavrba7kbcnmzwroavbi
more »... mputational techniques. The recent trends and advancements in the field of Artificial Intelligence (AI) have led the development of Swarm Intelligence (SI) based optimized controllers for smooth Renewable Energy Sources (RES) penetration and optimal voltage, frequency, and power-sharing regulation. Moreover, the recent studies have proved that the SI-based controllers provide enhanced dynamic response, optimized power quality and improved the dynamic stability of the MG systems as compared to the conventional control methods. Their importance in modern AC MG architectures can be judged from the growing number of publications in the recent past. However, literature, pertaining to SI applications to AC MG, is scattered with no comprehensive review on this significant development. As such, this study provides an overview of 15 different SI optimization techniques as applied to AC MG controls from 43 research publications including a detailed review of one of the elementary and most widely used SI based metaheuristic optimization algorithms called Particle Swarm Optimization (PSO) algorithm. This comprehensive review provides a valuable one-stop source of knowledge for the researchers and experts working on SI controller's applications for AC MG dynamic response and power quality improvements. INDEX TERMS AC micro-grids, optimization, artificial Intelligence, swarm intelligence, power quality, dynamic response enhancement.
Bilal Akram: performed TEM analysis. Ata Ulhaq and Bilal Ahmed: performed the Raman spectroscopy. Ming Xu co-advised the characterization and data analysis. ... Saif Ullah Awan and Naseem Iqbal: performed G.C., S.E.M. and E.D.A.X. analysis. Shamraiz Hussain Talib: performed the DFT measurements. Naveed Hussain: performed the XPS analysis. ...doi:10.1038/s41598-019-46544-7 pmid:31308407 pmcid:PMC6629633 fatcat:jltvgsfao5dqrfrlg4u5t3yzzi
This paper presents an intelligent voltage controller designed on the basis of an adaptive neuro-fuzzy inference system (ANFIS) for a flyback converter (FC) working in continuous conduction mode (CCM). The union of fuzzy logic (FL) and adaptive neural networks (ANN) makes ANFIS more robust against model parameters' uncertainties and perturbations in input voltage or load current. ANFIS inherits the advantages of structured knowledge representation from FL and learning capability from NN.doi:10.3390/app9235108 fatcat:degihrgqpbfepcqa54eqjue4nm
more »... tive analysis showed that the ANFIS controller offers not only the superior transient response characteristics, but also excellent steady-state characteristics compared to those of the FL controller (FLC) and proportional–integral–derivative (PID) controllers, thus validating its superiority over these traditional controllers. For this purpose, MATLAB/Simulink environment-based simulation results are presented for validation of the proposed converter compensated system under all operating conditions.
Archives of Medicine
Leptin is an important adipokine hormone released from adipose tissue which is associated with obesity and diabetes in different populations. Objective: To investigate the serum leptin concentrations for its correlation with diabetes, obesity and gender in a small population from Faisalabad, Pakistan. Methods: From our sample collection of more than 500 subjects for metabolic disorders research, we have carefully selected 80 subjects for the present case-control comparison study. These subjectsdoi:10.21767/1989-5216.1000169 fatcat:wzsftvolkze6jgrgwndql5kwya
more »... were grouped on the basis of diabetes, obesity and gender status. Equal number of subjects was taken for each comparison group to minimize the effects of confounding factors. For diabetes, these eighty subjects were divided into two groups (n=40 non-diabetic and n=40 type 2 diabetics). While considering obesity, these eighty subject were divided on the basis of their Body Mass Index (n=40 non-obese and n=40 obese). For gender based analysis, the groups based on diabetes and obesity were made (n=20 in each sub-group) and further analyzed while keeping n=10 males and n=10 females in each sub-group. Serum leptin and biochemical analytes were measured for all subjects and data were analyzed by SPSS 18.0 software. Results: Leptin levels were found significantly low in nonobese as compared to obese subjects (Mean ± SD: 5.2 ± 2.0 vs. 7.1 ± 2.1 ng/ml, p<0.001). No significant difference was found for non-diabetics and diabetics (6.4 ± 2.4 vs. 5.9 ± 2.2 ng/ml, p=0.35). Gender dimorphism showed significant differences for leptin (p<0.0001). Spearman's analysis showed strong correlation between leptin and obesity (r=0.43, p=0.0001), gender (r=0.24, p=0.02) irrespective of obesity or diabetes. Conclusion: The leptin levels were high in obese and female subjects.
The aim of this research is to perform an in-depth performance comparison of ground-mounted and rooftop photovoltaic (PV) systems. The PV modules are tilted to receive maximum solar irradiance. The efficiency of the PV system decreases due to the mutual shading impact of parallel tilted PV modules. The mutual shading decreases with the increasing interrow distance of parallel PV modules, but a distance that is too large causes an increase in land cost in the case of ground-mounted configurationdoi:10.3390/en13143639 fatcat:56tdxc4cxzcbvht42x7w6mq52e
more »... and a decrease in roof surface shading in the case of rooftop configuration, because larger sections of roof are exposed to sun radiation. Therefore, an optimized interrow distance for the two PV configurations is determined with the aim being to minimize the levelized cost of energy (LCoE) and maximize the energy yield. The model of the building is simulated in EnergyPlus software to determine the cooling load requirement and roof surface temperatures under different shading scenarios. The layout of the rooftop PV system is designed in Helioscope software. A detailed comparison of the two systems is carried out based on energy output, performance ratio, capacity utilization factor (CUF), energy yield, and LCoE. Compared to ground-mounted configuration, the rooftop PV configuration results in a 2.9% increase in CUF, and up to a 23.7% decrease in LCoE. The results of this research show that installing a PV system on a roof has many distinct advantages over ground-mounted PV systems such as the shading of the roof, which leads to the curtailment of the cooling energy requirements of the buildings in hot regions and land cost savings, especially for urban environments.
Due to the impediments of voltage source inverter and current source inverter, Z-Source Inverter (ZSI) has become notorious for better power quality in low and medium power applications. Several modifications are proposed for impedance source in the form of Quasi Z-Source Inverter (QZSI) and Neutral Point Clamped Z-Source Inverter (NPCZSI). However, due to the discontinuity of the source current, NPCZSI is not suitable for some applications, i.e., fuel cell, UPS, and hybrid electric vehicles.doi:10.3390/en13051261 fatcat:ydmccee6j5ftdg72lhrhoircla
more »... though in later advancements, source current becomes continuous in multilevel QZSI, low voltage gain, higher shoot-through duty ratio, lesser availability of modulation index, and higher voltage stress across switches are still an obstacle in NPCZSI. In this research work, a three-level high voltage gain Neutral Point Clamped Inverter (NPCI) that gives three-level AC output in a single stage, is proposed to boost up the DC voltage at the desired level. At the same time, it detains all the merits of previous topologies of three-level NPCZSI/QZSI. Simulations have been done in the MATLAB/Simulink environment to show the effectiveness of the proposed inverter topology.
Antibiotics discovery was a significant breakthrough in the field of therapeutic medicines, but the over (mis)use of such antibiotics (n parallel) caused the increasing number of resistant bacterial species at an ever-higher rate. This study was thus devised to assess the multi-drug resistant bacteria present in sanitation-related facilities in human workplaces. In this regard, samples were collected from different gender, location, and source-based facilities, and subsequent antibioticdoi:10.1101/2020.05.05.078485 fatcat:kdx7fjy7czfwbhfg5o2rig5kna
more »... ity testing was performed on isolated bacterial strains. Four classes of the most commonly used antibiotics i.e., β-lactam, Aminoglycosides, Macrolides, and Sulphonamides, were evaluated against the isolated bacteria. The antibiotic resistance profile of different (70) bacterial strains showed that the antibiotic resistance-based clusters also followed the grouping based on their isolation sources, mainly the gender. Twenty-three bacterial strains were further selected for their 16s rRNA gene based molecular identification and for phylogenetic analysis to evaluate the taxonomic evolution of antibiotic resistant bacteria. Moreover, the bacterial resistance to Sulphonamides and beta lactam was observed to be the most and to Aminoglycosides and macrolides as the least. Plasmid curing was also performed for MDR bacterial strains, which significantly abolished the resistance potential of bacterial strains for different antibiotics. These curing results suggested that the antibiotic resistance determinants in these purified bacterial strains are present on respective plasmids. Altogether, the data suggested that the human workplaces are the hotspot for the prevalence of MDR bacteria and thus may serve the source of horizontal gene transfer and further transmission to other environments.
Rankine cycle (Bilal Awan et al., 2020) is used in a power block to convert heat energy to electrical energy. ... PT is the most mature form of CSP where most of the CSP plants currently operating in the world are based on PT technology (Bilal Awan et al., 2020) . ...doi:10.1016/j.egyr.2021.07.042 fatcat:3viehq5owva3hbgj7nhwwmrhuu
AHMED BILAL AWAN received the B.Sc. degree in electrical engineering from the University of Engineering and Technology (UET), Lahore, Pakistan, in 2004, the master's degree from the École Supérieure d'Electricite ...doi:10.1109/access.2020.2979506 fatcat:xvmecv5mrrgv7osh6mshfrwena
Induction heating (IH) is an environmentally friendly solution for heating and melting processes. The required high-frequency magnetic field is accomplished through frequency controllers. Direct frequency controllers (DFC) are preferred to dual converters as they have low conversion losses, compact size, and simple circuit arrangement due to low component count. Numerous frequency controllers with complex switching algorithms are employed in the induction heating process. They have adoi:10.3390/electronics9030430 fatcat:sjr7nobn6fez7au7coovpcoyiq
more »... circuit arrangement, and complex control as their switching sequences have to synchronize with source voltage that requires the zero-crossing detection of the input voltage. They also have a shoot-through problem and poor power quality. Therefore, this research proposes a novel frequency controller with a low count of six controlled switching devices without a zero-crossing detector (ZCD) having a simple control arrangement. The required switching signals are simply generated by using any pulse-width-modulated (PWM) generator. The performance of the proposed topology is verified through simulation results obtained using the MATLAB/Simulink environment and experimental setup.
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