The Potential Induced Degradation (PID) of crystalline Si solar cells has been extensively investigated after being firstly reported by Pingel et al. (2010). Figure 2-21 (left) shows the setup of the PID experiment performed by the outhors. In this study they investigated the effect of the PID on the system, panel and cell level. At the system level the potential difference between PV system and ground is critical. At the module level, environmental parameters such as temperature and humidity are important. The intrusion of water in the module increases the encapsulant conductivity and so the leakage current. In the cell level the processing as well as the quality of the base material are critical. This effect is more pronounced in large PV system installations equiped with p-type Si crystalline PV cells. Due to the difference potential between the PV module and its structure, electrons can escape through the grounded wire when there is a lack of proper insulation. It generates leakage currents and this electrical current induced in the module causes a progressive performance deterioration (Ndiaye et al., 2013).
The analysis shows that the six performance indicators do not benchmark the PV panel output with its maximum output at the identical orientation angles, i.e. , inclination and azimuth angles which can be achieved with a solar tracker. This parameter is quite significant when it is required to compare the output of roof- top PVsystems for different roof designs. If the same design of PV system as- sessed at different latitudes using the six performance indicators different per- formance profile will be resulted by each indicator. The end user will not be able to comprehend why the PV system is not performing well art high irradiation condition compared with other lower irradiation sites. More clarification to this point is shown by Figure 5 and Figure 6 which represent the performance values
Now a day, switch over of living with more and more electronic devices the power demand get bigger. Due to the rise in demand the sources like coal depleting day by day. In order to compensate the needs, researchers, industries and government focus on inexhaustible renewable sources.Not only the wide implementation of distributed generation, some major points still need to be enhanced to get quality of power in the utility grid at levels required by standards to fulfill the consumer requirements. In this aspect one of the major problems is the synchronization of inverter output current with the voltage of utility grid .To track voltages and currents various PLL techniques have been proposed and are used for single phase systems, three phase systems as well as in aircraft electrical systems . Reference  contains an overview of the historical development of the phase locked loops, general information about their operation.Information and categorization of the most commonly used types of control and synchronization methods are presented in . Different approaches of the implementation of phase locked loop in three phase and single phase are presented in [11-12].
To study the importance of the BES in the performance of such a system, a hypothetical case study, incorporating high fidelity synthetic load profiles, was developed and simulated over the course of a year. It was found, as expected, that the battery system enabled a much higher self-sufficiency rate; at times this approached, on a population aggregated basis, unity, though for individual households this could be significantly lower. Seasonal variation of PV production provides a potential to operate the battery in a different way that enables the interaction with the power grid, which is significantly helpful when a time-of-use tariff is applied. Additionally, the battery can also enhance the stability of grid when abundant electricity is produced from PV, especially during summer.
Crawlers are being increasingly utilized to retrieve information from distributed information sources, such as the Web. We have implemented one that makes use of some novel algorithms and techniques, namely, a novel IR architecture, an efficient query expansion algorithm based on WordNet, a new crawling technique based on ontology and a new rapid filtering algorithm based on semantic similarity. The experimental results of the implemented crawler, named Ontology Based Distributed Information Retrieval (OBDIR) system, show superiority to those obtained from systems based on the standard Breadth First (BF) search technique. In this paper we analyze the performance of the OBDIR system. We develop a probabilistic model that captures the operational dimensions of the system. The model makes heavy use of Bayes’ theorem and can help establish a foundational theory for DIR. We study such performance metrics as recall and precision, and allude to other performance tools such as accuracy and ROC space. The study shows that by carefully choosing the keywords the performance of the crawler is enhanced greatly.
a secure operating system can act. Manufacturing companies of MOSs must itself the operating system security as far as possible of the design process, as well as their implementation. Security team, itself professional activity on how influence to an operating system know and can help production compa- nies that the operating system may be faced with the kind of attacks. Also security team in design test security to help Op- erating system company manufacturer. This team by knowing sensitive and critical parts the operating system can control access to files, events (including intrusion detection) guaran- tee. Thus, security teams experience of by using platform se- curity models and security tests could enhance the security of MOSs. Thus, identifying and analyzing vulnerabilities in each of MOSs result effort and processing teams of software securi- ty. And must companies of experience them for produce se- cure operating system to use. But we must note that no securi- ty method is not without errors and problems and better and more accurate analysis can be accelerated to the security of MOSs.
Scorecards should be monitored on an ongoing basis and benchmarked both internally against performance over time and externally against established best practices with the intent of continuous performance improvement. Our challenges in this work is to measure and monitor the performance of Moulay Youssef operating room trying to fill the weaknesses of previous studies by using: * A specific model of health care systems including both internal and external processes.
3.1 COMPARISON OF DESIGN AND OPERATING PARAMETER OF CONDENSER Insulation and steam drain systems based on present operating condition of plant and then compare it with design performance. The generating consists of two condenser units, each having same specification. The flow rate of water through the condenser, Temperature difference and pressure were measured. On the basis of site measurement and design data collection performance of the Condenser unit 1 can be evaluated.
Experiments are carried out for solar cell panel, with and without concentrators; for Mirror augmentation system and 2D CPC based system. In case of 3D CPC based system, single solar cell is tested with and without 3D CPC. The following results are obtained with the experimental analysis which is ultimately used for comparison between regular solar cell with compound parabolic concentration system and mirror augmented PV system. The results are shown in the tabulated form and the variation in temperature; time and intensity are represented graphically.
Abstract: It is well known that working PV plants show several maintenance needs due to wiring and modules degradation, mismatches, dust and PV cells defects and faults. There are a wide range of studies that show the theoretical and some laboratory tests of how these circumstances may affect the PV production. Thus, it results mandatory to evaluate the whole PV plant performance and, then, it’s payback time, profitability and environmental impact or carbon footprint. However, very few studies include a systematic procedure to quantify and supervise the real degradation effects and faults impacts on the field. In this paper, the authors first conduct a brief review of the most frequent PV faults and degradation that can be found on real conditions operative PV Plants. Then, they propose and develop an innovative Geographic Information System application to locate and supervise them. The designed tool has been applied to either a large PV plant of 108 kWp and a small PV plant of just 9 kWp installed on a home rooftop. For the large PV plant, 24 strings of PV modules have been modelized and introduced into the GIS application and every module in the power plant has been studied including voltage, current, power, series and parallel resistance, fill factor, normalized PV curve to STC, thermography and visual analysis. For the small PV installation 3 strings of PV panels have been studied identically. It must be noticed that PV modules in this case include power optimizers. The precision of the study allows the researchers to locate and supervise up to a third part of every PV cell in the system, which are adequately georreferenciated. The developed tool allows both the researchers and the investors to increase control on the PV plant performance and conducts to a better planification of maintenance actuations and to evaluate several PV modules replacement strategies in a preventive maintenance programme. Found PV faults include hot spots, snail tracks, EVA discoloration, PV cells fractures, busbars discoloration, bubbles and Si discoloration.
With a web browser the data of PV plants from different countries, sizes, and years of construction acquired and evaluated during the Task 2 (1993-2007) and Task 13 (after 2010) , can be accessed with an easy to use graphical interface. A search function allows for access to the data of a specific plant. In the overview “Plant” the most important project specific data such as nominal power, number of modules or geographic location can be viewed. In further menus more detailed information such as type of the inverters and modules or the combination of the modules to strings can be accessed. The recorded data is evaluated and displayed in tables and graphs on a monthly base and in an annual overview, such as shown in Figure 3. The exemplary graph shows the monthly data from 2012 of a PV plant at Bolzano airport in Italy.
This study investigates the effect of operating parameters on the electrochemical (anodic) degradation of estriol (E3) in aqueous solutions. We mainly focused on the use of a boron-doped diamond (BDD) electrode for the E3 degradation at various current densities, initial E3 concentrations, and temperatures. The performance of BDD for E3 degradation was compared with that of Ti/Pt and a dimensional stable anode (DSA). The oxidation of E3 on BDD was found to be electrochemically irreversible according to cyclic voltammetric analysis. In electrolysis, the degradation (anodic oxidation) of E3 was a pseudo-first-order (kinetic) reaction, which yielded an apparent rate constant of 8.9×10 -3
High-Performance Constant Power Generation in Grid-Connected PVSystems is discussed in this paper, which can ensure a fast and smooth transition between maximum power point tracking and Constant Power Generation (CPG). A two- stage grid-connected PV is employed to extend the operating area of the P&O-CPG algorithm.
In Markov models the holding times are exponentially distributed which is often too restrictive and might not fit the actual operating data well. Considering more general holding times leads to semi-Markov processes which are less amenable to analytic treatment but provide more flexible models. To this effect a generalized algorithm was developed and applied to single two unit ideal systems. By varying various parameters the sensitiveness of dependability analysis carried out and found satisfactory. The technique can be extended to multi-unit systems for transient availability analysis. The limitation of integer constrained arisen during the assessment of number of stages can be further worked out to have an effective dependability analysis. As method of stages are specifically applicable to Weibull case with shape parameter greater than unity, for less than one appropriate algorithm is to be developed which can be considered as extension of this study.
Moreover , when ever the output power reach the Plimit, then the output power of the PV system will be kept constant, i.e., Ppv = Plimit, which leading to the constant active power which is injected as shown in (1) and it also illustrated in Fig. 1 In terms of the algorithms and the CPG which is based upon the Perturb and Observe (P&O-CPG) algorithm which was introduced by the single stage PVsystems . moreover during the operating area of the CPG control which is limited at the right side of the Maximum Power Point (MPP) of the PV arrays (CPP-R), due to its single-stage configuration. Unfortunately it will reduce the robustness of the control algorithm when the PVsystems is experience with the fast decrease during the irradiance time .
Grid-connected solar PVsystems, though the fastest growing renewable energy technology in the world, have not been fully exploited in India; one of the reasons being the very high initial investment . Prices of solar PVsystems have however been on a decline for the past few years due to technological innovations which have led to improvements in cell efficiencies and the economies of scale resulting from increase in production. The main purpose of this paper is to present a technical and economic analysis of grid- connected solar photovoltaic power system for the Indore, Madhya Pradesh, India.
atmosphere and other pollutions, the panels may show only poor performance. Also there are chances of having any plant near the panels that offers shade as it grow in to tree as years pass by. Thus the area of MPPT algorithm is being expanded, considering not just the incoming solar irradiance, but also the system and load.
Abstract— Cloud computing has simply means Internet Computing. The Internet is commonly visualized as clouds. Hence the term cloud computing for computation done through the Internet. With Cloud computing users can access database resources via the Internet from anywhere. Cloud computing provides the facility to access shared resources and common infrastructure, offering services on demand over the network to perform operations that meet changing business needs. The virtualization of IT infrastructure enables the consolidation and pooling of IT resources so that they can be shared over diverse applications. With the help of virtualization logical abstraction of physical resource is possible which is very lucrative for the IT business. Thus we can save the capital of IT business. Virtualization is very important for cloud computing because the delivery of services is simplified by providing a platform, infrastructure and services for optimizing complex IT resources in a feasible manner, which makes cloud computing more cost effective. This paper presents PerformanceAnalysis of Various Guest OperatingSystems on Ubuntu 14.04.Various Guest OS performance on Ubuntu cloud of different virtual machine of Ubuntu and WinXP’s performance in the CPU Time, Memory usage, and percent CPU usage in the KVM hypervisor virtualization. Our comparison was carried using Libvirt tool kit commands result and sysbench benchmark tool. Our goals are that how the different virtual machine of single host affects the performance and make informed decision about choice of best virtual machine indication to the cloud guest OS on Ubuntu.
requirement for a successful photovoltaic concentrator is a cooling system which can efficiently remove the dissipated heat while keeping the cells at the desired temperature. Concentrating sunlight onto photovoltaic cells, thus replacing expensive photovoltaic area with less expensive concentrating mirrors or lenses, is seen as one method to lower the cost of solar electricity. Because of the smaller area, more costly, but higher efficiency PV cells (special cells) may be used. However, only a small portion of the incoming sunlight onto the cell is converted into electrical energy (a typical efficiency value for concentrator cells is 25% ). The remainder of the incoming energy will be converted into thermal energy in the cell and cause the junction temperature to rise unless the heat is efficiently dissipated to the environment. The photovoltaic cell efficiency decreases with increasing temperature [5-6]. Cells will also exhibit long-term degradation if the temperature exceeds certain limit [7, 8]. The cell manufacturer will generally specify a given temperature degradation coefficient and a maximum operating temperature for the cell. The cell efficiency is known to decrease due to non-uniform temperatures across the cell [9, 10]. In a photovoltaic module, a number of cells are electrically connected in series, and several of these series connections can be connected in parallel. Series connections increase the output voltage, while the parallel connection increases the current. The aim of this paper is to study the effect of temperature on performance of PV system operating under concentration to get solutions to minimize the cost of 1kwh.
An embedded system is hardware/ software co-design methodology, to perform specific task . Most of the embedded systems are the real time where all tasks must execute within their timing constraints even in the presence of faults. Embedded Systems are used everywhere, Millions of embedded systems build every year for different purposes, 98% computing devices in the world are embedded systems. Safety-critical embedded systems have to satisfy cost and performance constraints even in the presence of faults. When the use of fault-tolerant real-time embedded systems, we tried to integrate fault tolerance techniques and task scheduling. Reliability requirement in safety-critical embedded system can be achieved by fault tolerance techniques. Scheduling is the process of selecting the next request . Designing of Real-time embedded system is always a challenging task. To evaluate system performance before implementation on hardware is also most challenging task. Some research work has been done to address this problem. The problem becomes even more complex with RTS because not all RTS use RTOS  so designers now have to spend a lot of time to study different implementations before choosing the right design for the target application. In this paper, we tackle the performance evaluation problem and explore different methods to evaluate the performance. We are extending the work done in  and present a comparative analysis of two different techniques that evaluate the performance based on the parameters average waiting time and average turnaround time. The system compares the performances of both scheduling algorithms and finds out the best for designing of embedded real-time operating System.