Solar photovoltaic (PV) energy; latest developments in the building integrated and hybrid PV systems

Environmental concerns are growing and interest in environmental issues is increasing and the idea of generating electricity with less pollution is becoming more and more attractive. Unlike conventional generation systems, fuel of the solar photovoltaic energy is available at no cost. And solar photovoltaic energy systems generate electricity pollution-free and can easily be installed on the roof of residential as well as on the wall of commercial buildings as grid-connected PV application. In addition to grid-connected rooftop PV systems, solar photovoltaic energy offers a solution for supplying electricity to remote located communities and facilities, those not accessible by electricity companies.The interest in solar photovoltaic energy is growing worldwide. Today, more than 3500 MW of photovoltaic systems have been installed all over the world. Since 1970, the PV price has continuously dropped [8]. This price drop has encouraged worldwide application of small-scale residential PV systems. These recent developments have led researchers concerned with the environment to undertake extensive research projects for harnessing renewable energy sources including solar energy. The usage of solar photovoltaic as a source of energy is considered more seriously making future of this technology looks promising.The objective of this contribution is to present the latest developments in the area of solar photovoltaic energy systems. A further objective of this contribution is to discuss the long-term prospect of the solar photovoltaic energy as a sustainable energy supply.     

A Potential Soot Mass Determination Method from Resistivity Measurement of Thermophoretically Deposited Soot

Miniaturized detection systems for nanometer-sized airborne particles are in demand, for example in applications for onboard diagnostics downstream particulate filters in modern diesel engines. A soot sensor based on resistivity measurements was developed and characterized. This involved generation of soot particles using a quenched co-flow diffusion flame; depositing the particles onto a sensor substrate using thermophoresis and particle detection using a finger electrode structure, patterned on thermally oxidized silicon substrate. The generated soot particles were characterized using techniques including Scanning Mobility Particle Sizer for mobility size distributions, Differential Mobility Analyzer—Aerosol Particle Mass analyzer for the mass–mobility relationship, and Transmission Electron Microscopy for morphology. The generated particles were similar to particles from diesel engines in concentration, mobility size distribution, and mass fractal dimension. The primary particle size, effective density and organic mass fraction were slightly lower than values reported for diesel engines. The response measured with the sensors was largely dependent on particle mass concentration, but increased with increasing soot aggregate mobility size. Detection down to cumulative mass as small as 20–30 μg has been demonstrated. The detection limit can be improved by using a more sensitive resistance meter, modified deposition cell, larger flow rates of soot aerosol and modifying the sensor surface.     

Underground coal gasification: From fundamentals to applications

Underground coal gasification (UCG) is a promising option for the future use of un-worked coal. UCG permits coal to be gasified in situ within the coal seam, via a matrix of wells. The coal is ignited and air is injected underground to sustain a fire, which is essentially used to “mine” the coal and produce a combustible synthetic gas which can be used for industrial heating, power generation or the manufacture of hydrogen, synthetic natural gas or diesel fuel. As compared with conventional mining and surface gasification, UCG promises lower capital/operating costs and also has other advantages, such as no human labor underground. In addition, UCG has the potential to be linked with carbon capture and sequestration. The increasing demand for energy, depletion of oil, and gas resources, and threat of global climate change have lead to growing interest in UCG throughout the world. The potential for UCG to access low grade, inaccessible coal resources and convert them commercially and competitively into syngas is enormous, with potential applications in power, fuel, and chemical production. This article reviews the literature on UCG and research contributions are reported UCG with main emphasis given to the chemical and physical characteristic of feedstock, process chemistry, gasifier designs, and operating conditions. This is done to provide a general background and allow the reader to understand the influence of operating variables on UCG. Thermodynamic studies of UCG with emphasis on gasifier operation optimization based on thermodynamics, biomass gasification reaction engineering and particularly recently developed kinetic models, advantages and the technical challenges for UCG, and finally, the future prospects for UCG technology are also reviewed.     

Modeling the Presence of Humic Acid in Ultrafiltration of Xenobiotic Compounds: Elman Recurrent Neural Network

Predicting the rejection of pesticides in ultrafiltration (UF) processes in the presence of common components of dissolved natural organic matter would be taken into consideration as a principle for surface water treatment. This paper presents the application of the Elman Recurrent Neural Network (ERNN) model, which has been trained with previously‐obtained experimental data so as to predict the rejection of a class of xenobiotic compounds (nitrophenols (NPs)) dynamically, in the absence and in the presence of humic acid at neutral and acidic conditions. For each trained network, the training function, number of neurons in the hidden and output layers, number of epochs, train and test MSE (mean square error) and MRE (mean relative error) were compared to find the best ERNN. The trained MRE and test MSE for all NPs at the neutral condition was, respectively, less than 1.03 % (4.9 % at acidic condition) and 2.4 % (2.01 % at acidic condition), which showed high network reliability.     

Greener energy: Issues and challenges for Pakistan-hydel power prospective

Water is a vital resource that supports all forms of life on earth. Progressive release of greenhouse gases (GHG) from increasing energy-intensive industries has eventually caused human civilization to suffer. During the past two decades, the risk and reality of environmental degradation have become more apparent. Renewable Energy provides an effective option for the provision of energy services from the technical point of view while hydropower, a major source of energy in the, appears an important renewable source of energy, its viability for large-scale energy production. Hydropower is renewable, reliable, clean, and largely carbon-free, and represents a flexible peak-load technology. With most of the world's hydropower potential available for near future development, it is local interests and sovereign states that decide how to manage their water resource base. In Pakistan the availability of power had been continually falling short of the demand of 24,474 MW and as a result, the country is experiencing power shortages of varying degrees in different parts of the country. Geographically, Pakistan has been blessed with river flows that are naturally supportive to electricity generation. Considering the large potential and the intrinsic characteristics of hydropower in promoting the country's energy security and flexibility in system operation, government is tried to accelerate hydropower development through number of policy initiatives. This paper investigates the progress and challenges for hydel power generation in Pakistan according to the overall concept of sustainable development and identifies the region wise potential of hydel power in Pakistan, its current status. Barriers are examined and Policy issue and institutional roles and responsibilities are discussed.     

Development of a New Simulation Model for the Reservoir Hydropower Generation

Hydroelectric power development plans are of great importance in today’s world, due to the urgency of access to clean energy resources. Hydroelectric power plants are great potentials for power generation around the world which produce less environmental problems. Hydroelectric power energy has covered 24% of the electrical energy in 2013. The proportion of this kind of energy is increasing rapidly. The amount of energy produced in different seasons of the year and different hours of the day is one of the most important issues in water plants. In other words, determining the capacity of installation (design discharge) is one of the important factors in the design of power plants. In this research, a developed algorithm for simulating hydropower energy production has been developed using MATLAB application. This developed model has been used for hydropower modeling. In such a situation, simulating energy production of the dam has been conducted for different power plant installation capacity and finally with applying reliability index of 90%, the installation capacity of the power plant equals 2.7 Kilowatt. In this installation capacity, initial energy and surplus has occurred in most months. Furthermore, in 33% of cases that the reservoir is in its maximum balance, surplus energy has been generated. Moreover, the scale of initial energy and the average surplus energy respectively equals to 20.80 and 13.2 Gigawatt hours annually on 24-h basis. By changing the input variables, this algorithm and the developed model can be applied in any single hydropower reservoir system.

     

Energy Efficient Reservation-Based Cluster Head Selection in WSNs

Due to the type of applications, wireless sensor nodes must always be inexpensive and small. Hence, the presence of constraints such as the limitation of energy resource is inevitable. So far, several studies have been carried out in order to present solutions for the reduction of energy consumption. In the meantime, clustering is given prime significance as an efficient method, which means partitioning network into distinct areas and is a way for managing nodes communication. In clustering algorithms, although the continuous execution of clustering phase and dynamic cluster head selection lead to energy consumption parity, they cause considerable energy dissipation due to the need for message transmitting to set new clusters and cluster heads. In this paper, the effect of using reservation to reduce message transmitting and energy dissipation has been studied. Reservation is the mechanism by the aid of which the number of communicated messages for the regular execution of clustering phase and cluster head selection can be reduced. The results of analysis and simulation show that the proposed method has significant impact on energy dissipation reduction.     

Physical properties of edible emulsified films based on pistachio globulin protein and fatty acids

Novel edible composite films were prepared from pistachio globulin protein (PGP), saturated fatty acids, and an emulsifier using the emulsification technique. The water vapor permeability (WVP) of the emulsified films was reduced by approximately 37–43% by fatty acid addition. The effect of fatty acid on the oxygen permeability (OP) of PGP films was indirectly determined as the oil peroxide value. The OPs of the emulsified films were lower than those of a PGP film without fatty acid, but the differences were not significant (P < 0.05). The mechanical properties of PGP films were also affected by fatty acid addition; the ultimate tensile strength (UTS) was diminished, and elongation at breaking (E) decreased considerably (35–70%). Furthermore, the incorporation of fatty acid increased the opacity of the films. Finally, differential scanning calorimetry showed that the glass transition temperature (T_g) of the PGP film was ∼127 °C and was not considerably affected by fatty acid addition.     

Oil Content and Composition of Sesame (Sesamum indicum L.) Genotypes as Affected by Irrigation Regimes

The fatty acid composition of sesame seed oil determines its commercial value, and drought stress and genotype may affect both the quality and quantity of oil that is extractable by sesame seed processors. Therefore, this experiment was conducted in a field located in Isfahan, Iran, to determine the effect of three irrigation regimes [55 % (I ₁, as control), 75 % (I ₂) and 85 % (I ₃) of depletion of soil available water] on the oil content and composition of ten sesame genotypes (Isfahan4, Shahreza, Borazjan, Ahvaz, Kal, Shiraz, Markazi, Ardestan, Ultan and Isfahan1). Seed oil content and palmitic, linoleic, linolenic, stearic and oleic acid contents were determined during 2010–2012. Shahreza under I ₁, Shahreza and Ardestan under I ₂ and Isfanahan4 under I ₃ irrigation regimes produced the highest oil content, while Kal under I ₁ and I ₂ and Isfahan4 under I ₃ irrigation regimes produced the highest oil yield. Ultan had the lowest palmitic acid content under all three irrigation regimes, while Isfahan4 had the highest reduction in palmitic acid content under I ₂ and I ₃. Borazjan produced the lowest stearic and highest linoleic acid contents under the I ₁, I ₂ and I ₃ irrigation regimes. Kal, Kal and Ardestan, and Ardestan and Isfahan1 produced the highest oleic acid under I ₁, I ₂ and I ₃, respectively. Shahreza under I ₁ and I ₂ and Isfahan4 under I ₃ had the highest linolenic acid content. The results showed that the sesame oil content and composition were genotype-drought level specific, and based on oil yield production and percent reduction in saturated and increase in unsaturated fatty acid contents, Isfahan4 was the most drought-tolerant genotype.     

Optimization of phthalic/maleic anhydride‐endcapped PET oligomers using response surface method

Poly(ethylene terephthalate) (PET) from off‐grades of industrial manufacturers was partially and thoroughly depolymerized in order to synthesize PET oligomers and bis(hydroxyethyl) terephthalate (BHET), respectively. Design of experiments and analysis of variance (ANOVA) were applied for optimization of samples. Effects of reaction time, volume of glycol, catalyst concentrations, and particle size of off‐grade PET were investigated. The optimal conditions to synthesize PET oligomers (3–8 repeating units) were glycol/PET molar ratio of 1, a weight ratio (catalyst to PET) of 0.5 wt%, using granule‐shape. On the other hand, a reaction time of 180 min, a weight ratio (catalyst to PET) of 0.25 wt%, and glycol/PET molar ratio of 5 were obtained as the suitable conditions of BHET production. Then, endcapped PET oligomers, as a compatibilizer for preparing PET nanocomposites, were produced via reaction between maleic anhydride/phthalic anhydride (MA/PhA) composition. The combination of reaction time of 106 min and PhA/MA molar ratio of 0.85 produced the best results based on d‐spacing and peak shift of nanocomposite samples. Moreover, the reaction of MA and BHET from glycolyzation of PET was successfully performed at 160°C and 190°C for 8 h. The optimum conditions were compared with a synthesized PET. POLYM. ENG. SCI., 54:417–429, 2014. © 2013 Society of Plastics Engineers