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Environmental, economic and strategic reasons are behind the rapid impulse in the deployment of renewable energy sources that is taking place around the world. Microgrid technology can effectively integrate the advantages of distributed generation, and also provide a new technical way for large scale application of grid-connected generation of new energy and renewable energy. The Palestinian territories are facing critical situation concerning the achievement of sustainable development. As an example, we know Energy is the main player in the community’s development in several aspects, but Palestine is an occupied developing country which has a complicated energy sector. In recent years, the Gaza Strip has suffered from several wars that have led to the collapse of its energy system, and this calls for research in providing alternative sources for conventional energy. In this paper, a solar-biomass hybrid system is proposed for electrification of rural area in GAZA strip, the city of TIKA. We used olive oil mill waste as a biomass. We used HOMER program to develop an optimal system from the practical view point. HOMER, software has been used to expose combined cycle with biomass and solar resources الأسباب البيئية والاقتصادية والاستراتيجية وراء الاندفاع السريع في نشر مصادر الطاقة المتجددة التي تحدث في جميع أنحاء العالم. يمكن لتقنية Microgrid أن تدمج بشكل فعال مزايا التوليد الموزع ، وتوفر أيضًا طريقة تقنية جديدة للتطبيق على نطاق واسع للتوليد المتصل بالشبكة من الطاقة الجديدة والطاقة المتجددة. تواجه الأراضي الفلسطينية وضعا حرجا فيما يتعلق بتحقيق التنمية المستدامة. على سبيل المثال ، نعلم أن الطاقة هي اللاعب الرئيسي في تنمية المجتمع من عدة جوانب ، لكن فلسطين دولة نامية محتلة لديها قطاع طاقة معقد. عانى قطاع غزة في السنوات الأخيرة من عدة حروب أدت إلى انهيار نظام الطاقة فيه ، وهذا يستدعي البحث في توفير مصادر بديلة للطاقة التقليدية. في هذا البحث ، تم اقتراح نظام هجين للطاقة الشمسية والكتلة الحيوية لكهربة المناطق الريفية في قطاع غزة ، مدينة تيكا. استخدمنا مخلفات مطاحن زيت الزيتون ككتلة حيوية. استخدمنا برنامج HOMER لتطوير نظام مثالي من وجهة نظر عملية. تم استخدام برنامج HOMER لفضح الدورة المركبة مع الكتلة الحيوية والموارد الشمسية

Numerical simulations based on the Monte Carlo Potts model are used to study coupling of grain growth and Ostwald ripening in two-phase polycrystalline materials. The ratio of the grain boundary energy to the interphase boundary energy is used as an input parameter. It is shown that the grain growth in two-phase polycrystalline materials is controlled by long-range diffusion and the change of the mean grain size with time obeys the growth law,< R> n=< R> 0 n+ kt where n is the grain growth exponent. The value of n is calculated for a broad series of volume fractions. It is found that the inverse grain growth exponent, 1/n, in agreement with the theoretical value, 1/n= 1/3, noticed during computer simulations for volume fractions between 40% and 90%. However, the value of 1/n is smaller than 1/3 for volume fractions between 10% and 30%. Furthermore, the temporal development of the number of grains has been analyzed for the entire range of volume fractions. It is also seen that the quasi-stationary state is advanced at varied aging times depending on the volume fractions. Furthermore, it is shown that the simulated size distribution are symmetric and peaked at x= 1 for volume fractions differ between 50% and 90%; however, the simulated size distribution become asymmetric and skew to smaller grains for lower volume fractions change between 10% and 40%.

A four layer waveguide has been introduced. Graphene layer is separate by metamaterial layer (MTM) from a plasmonic layer The dispersion characteristics of the propagation of TM surface Plasmon through the waveguide structure containing a graphene have been derived. We numerically analyse the propagation of surface plasmon at different waveguide parameters. The obtained results presents that we can control the propagation of the plasom as we changes the thickness of the MTM layer, the MTM parameters, and the graphened conductivity.

Practically most polycrystalline materials such as ceramics are sintered by liquid during processing; for example, tungsten carbide applied for cutting tools. In liquid sintering, grain structure is controlled by Ostwald ripening. In this work, the Monte Carlo Potts model is employed to simulate Ostwald ripening in solid-liquid mixture. Based on the computer simulation

Solar energy is an important source of renewable energy due to the easy access to the source. One drawback in this system is achieving the maximum efficiency of the system. The photovoltaic (PV) cell is the fundamental unit in the power conversion of the solar system. The extracted maximum output power of PV cell reduces when it exposes to partial shading causing remarkable reduction in the efficiency of the system. In this work, PV modules under various shading condition is simulated using Matlab/Simulink. Results show that the power-voltage (PV) characteristic of PV modules exhibit several local maximum power points (MPP) in comparison with unique MPP in case of full insolation causing more complication to the system and a noticeable reduction in the efficiency of the system.

Liquid phase sintering is a process in which solid grains coexist with a liquid matrix. This process has important applications in processing of several engineering materials. Examples of these applications are high-speed metal cutting tools, alumina substrates for packaging silicon chips and barium titanate electrical capacitor. Grain growth in liquid phase sintered materials occurs by Ostwald ripening. The purpose of this paper is developing Monte Carlo Potts model to simulate Ostwald ripening in liquid-phase sintered materials. Ostwald ripening is simulated by treating two phases, solid grains dispersed in a liquid matrix as a two-dimensional square array of sites. Each site of the solid-phase grains (phase A) is given a random positive number between 1 and Q where Q=100 for all the simulation. The sites of the liquid phase (phase B) are assigned only one negative number, qB = -1. It is found that the grain growth is controlled byvolume diffusion for volume fraction of the solid grains ranging from 40% to 90%. The grain growth exponent has the value, n=3, in agreement with the theoretical value of Ostwald ripening.

This paper proposes a voltage control oscillator (VCO) at high frequency consists of nonlinear composite right/left-handed transmission line (CRLH-TL) loaded with Resonant Tunneling Diode (RTD). The system has equals input and output resistance. In this work, we used OrCAD and ADS software to analyze the proposed circuit. The VCO capable of generating oscillation at frequency equals 14.4 GHz. Voltage controlled oscillator (VCO) has several applications in communications and sensing network. It plays an important role in converting DC values that detected from thermometer, pH sensor, or pressure sensor into frequencies. In this work, we proposed a compact voltage controlled oscillator (VCO) based on hybrid composite right/left metamaterials transmission lines (CRLMTL) loaded with resonant tunneling diode (RTD). RTD has interesting applications referring to its high switching speed where it can reach up to 2.2 THz and to its IV characteristic that often exhibits negative differential resistance regions [1]. The RTD is placed parallel with shunt inductor of CRLH-TL hybrid approach as shown in Fig. 1. The hybrid resonant unit cell consists of a microstrip line with a series gap and two shunt stubs etched in the strip and a complementary split-rings resonators (CSRR) printed in the ground plane [2]. The desired system has been achieved by loading the unit by input and output impedances that have equal value. In this work, we take it equals 50 Ω. We used OrCAD and ADS softwares to analyze the proposed circuit. The output of the oscillator is measured at different values of the biasing voltage of the RTD. The biasing is used to ensure that …

Liquid phase sintering is a process in which solid grains coexist with a liquid matrix. This process has important applications in processing of several engineering materials. Examples of these applications are high-speed metal cutting tools, alumina substrates for packaging silicon chips and barium titanate electrical capacitor. Grain growth in liquid phase sintered materials occurs by Ostwald ripening. The purpose of this paper is developing Monte Carlo Potts model to simulate Ostwald ripening in liquid-phase sintered materials. Ostwald ripening is simulated by treating two phases, solid grains dispersed in a liquid matrix as a two-dimensional square array of sites. Each site of the solid-phase grains (phase A) is given a random positive number between 1 and Q where Q=100 for all the simulation. The sites of the liquid phase (phase B) are assigned only one negative number, qB = -1. It is found that the grain growth is controlled by volume diffusion for volume fraction of the solid grains ranging from 40% to 90%. The grain growth exponent has the value, n=3, in agreement with the theoretical value of Ostwald ripening.

Nonlinear transmission lines (NLTL) that consist of coplanar waveguide periodically loaded with resonant tunnel diode are capable of shaping signal waveforms during transmission. Such system is the basis of very interesting microwave signal generation circuits and it has a lot of applications in electronics. Pspice is used to model analog to digital converter by generating short electrical pulses on a nonlinear transmission line. Nonlinear transmission line is realized as electrical lattice with N electrical cells coupled by inductor and resistor in series. Each cell consists of a resonant tunnel diode in parallel with both resistor and capacitor. Attenuation represented by the resistor is cancelled by nonlinear effect. This cancellation produces the desired effect.

In this study, a four-layer waveguide structure has been investigated as a solar cell model. In the proposed structure, a nanoparticle composite layer is added to enhance the efficiency of the solar cell due to their ability of controlling the light transmission and reflection. The nanoparticles are taken to be a mixture of Ag and Au embedded in a dielectric media consists of polyacrylic acid laid above a SiNx antireflection coating layer. Both layers are sandwiched between glass substrate and air cladding. The average reflectance for TE and TM fields are calculated using Maple. Results show that the reflectance depends on the ratio of the nanoparticle in the dielectric media, refractive index of SiNx layer and the angle of incidence. Thus, the performance of solar cell has been optimized by tuning and adjusting the above-mentioned parameters.

mediaTUM; Universitätsbibliothek; Technische Universität München. Logo. Benutzer: Gast Login: de; en. Erweiterte Suche. mediaTUM Gesamtbestand. mediaTUM Gesamtbestand Einrichtungen Fakultäten Fakultät für Elektrotechnik und Informationstechnik Lehrstühle und Professuren Lehrstuhl für Messsystem- und Sensortechnik (Prof. Koch) Publikationen 2009. Dokumenttyp: Konferenzbeitrag. Art des Konferenzbeitrags: Vortrag / Präsentation. Autor(en): El-Khozondar, H.; Müller, MS; El-Khozondar, R.; Koch, Alexander W. Titel: Twist Effect on Polarization Maintaining Fiber. Kongress- / Buchtitel: German Middle-East International Conference. Kongress / Zusatzinformationen: 11.05.2009, Amman, Jordanien. Jahr: 2009. Sprache: en. Format: Text. BibTeX …

Most engineering alloys are used in polycrystalline form. This means that they are made of a large number of grains. The structure formed by the grains is not steady but evolves with time. Understanding the material's microstructure and its evolution helps to control the performance and lifetime of engineering materials. The simulation method based on the Monte Carlo–Potts model of microstructural evolution in a two-phase system has been extended to study microstructural evolution in a three-phase system. The model has been developed and characterized in this study. The model is verified by comparing simulation results of grain growth in the three-phase system to the simulation results in a two-phase system. It is found that grain growth is controlled by diffusion along grain boundaries and follows the power-growth relationship, d~ t 1/n with 1/n= ¼.

A theoretical approach to study the influence of temperature stress of the thermal sensitivity of the effective refractive index for asymmetrical nonlinear optical waveguides is developed. The structure of the waveguide sensor consists of thin film surrounded by nonlinear cladding and linear substrate. In the proposed waveguide sensor, temperature stress is induced due to the different thermal expansion coefficients of the substrate, core and cladding. Numerical calculation is carried out to draw the thermal sensitivities of effective refractive indices against the core thickness for both transverse electric modes (TE) and transverse magnetic modes (TM). The relation between thermal sensitivities and different temperature stress gradient is derived and plotted. Based on the results, thermal sensitivity of the sensor can be controlled by temperature stresses which can be controlled by carefully picking the materials and loading methods. Keywords: temperature sensitivity, stress, nonlinear waveguide, thermal stress, optical parameters, sensor

A quantity of vital engineering materials is example of two-phase materials in which each phase may be polycrystalline. In numerous cases, both phases of these materials may undergo grain growth which may affect their electrical and mechanical properties. Therefor, substantial efforts have been devoted to understand the microstructural evolution of polycrystals to improve their performance in microelectronic industries. Numerical method based on Monte Carlo Potts model is used to investigate microstructural evolution of two-phase polycrystalline materials in which grain growth in both cases is controlled by grain boundary diffusion (n= 4). It is shown that the microstructural evolution of two-phase polycrystals eventually reaches an asymptotic regime in which grain growth in both phases is coupled due to Zener pinning and obeys a power-law relationship d~ t1/n. This conclusion is valid in a broad parameter range and is compatible with theoretical predictions and laboratory experiments.

Mechanical properties of materials are determined by their microstructure. Therefore, studying microstructural evolution of TiAl/Ti_3Al lamellar alloys helps to improve their properties and enhance their performance for high-temperature engineering applications. The emphasis of our study is the growth kinetics of coarsening of lamellar structures. Microstructural evolution of TiAl/Ti_3Al lamellar alloys is studied by using computer simulations based on Monte Carlo Potts model. The initial microstructure is generated by arranging a stack of alternating parallel layers of TiAl phase and Ti_3Al phase with spacing proportional to their volume fraction. An array of faults is introduced to the lamellae to induce instability in the system. We find that an isotropic lamellar structure degenerates via edge spheroidization and termination migration into nearly equiaxed grains with a diameter which is 2 to 3 times larger than the initial …

Practically all metals, ceramics and rocks are polycrystalline materials which consist of a mixture of tiny grains (single crystals) which are" glued" together by interatomic forces. Polycrystals are intrinsically unstable. They undergo various changes with time, which, in turn, affect other physical and mechanical properties of the materials such as their strength and creep resistance. Therefore, understanding the microstructural evolution is very important in many practical and theoretical applications. Understanding the microstructural evolution in metals and ceramics helps to control the properties of these materials and enhance their performance in industrial applications. Understanding the microstructural evolution in rocks is also essential to theories of the dynamics of solid interior of the Earth. Computational methods proved to be very useful for studying microstructural evolution. Furthermore, this is, perhaps, the only …

Understanding the microstructural evolution in rocks is essential to theories of the dynamics of the solid interior of the Earth. The eutectoid transformation at 660 km depth produces alternating thin lamellae of pervoskite and magnesiowüstite.

Since it has been realized that the viscosity of the lower mantle depends on the grain size, several studies have been conducted to constrain grain size in the lower mantle. One of the problems is that the initial structure generated by spinel-perovskite phase transformation is characterized by lamellae of alternating perovskite and magnesioüstite. It is not clear how long it takes for such structures to reach the asymptotic regime of conventional Ostwald ripening and whether this can happen on typical time scales of laboratory experiments. We performed numerical simulations of coarsening of lamellar structures using Monte Carlo Potts model. We find that at high temperatures, an isotropic lamellar structure degenerates into nearly equiaxed grains with the diameter which is 2 to 3 times larger that the original lamellar spacing. The duration of this process is comparable with that expected for conventional Ostwald …

▪ Introducing a new photonic structure, which is composed of alternating lamellae of MTMs and Dielectric to extend the applications of photonic crystals (PCs).▪ Use computing approach based on data mining techniques to study one of the business fields to produce a business technique that helps in extraction the association rules for the incubated startup companies. ▪ Develop the Monte Carlo Potts model to investigate microstructural evolution of polycrystalline materials. The emphasis is on coarsening of two-phase systems. In particular, the model is applied to investigate the microstructural evolution in a twophase system in which both phase grow simultaneously. It is shown that a two-phase system with initially small grains eventually reaches an asymptotic regime in which grain growth in both phases is coupled due to Zener pinning and obeys a power-law scaling relationship. This conclusion is valid in a broad …