Antennas play very important role in the performance and consistency of any wireless communication system. In this work we have design, investigate, and optimize the various parameters as well as the bandwidth of a multi-band microstrip antenna using different positions of slot patch and defected ground plane structures (DGS) techniques. A Roger RT/ duroid 5880 substrate with dielectric constant 2.2, and ground plane with an area of 80mm×90mm have been chosen for operation at three different frequency bands centered at (2.30-2.7) GHz, (4.0-4.7) GHz and (5.2-5.8) GHz. The operation scope of the proposed structures is intended to work for WLAN, IMT (International mobile telecommunications) and WiMAX applications. Ansoft-High Frequency Structured Simulation package (Ansoft-HFSS) has been used as realization software of the proposed antennas.

In first stage of each microwave receiver there is Low Noise Amplifier (LNA) circuit, and this stage has important rule in minimizing the system noise figure, provide enough gain with sufficient linearity, and assure a stable 50 Ω input impedance at a low power consumption. The design of a LNA in Radio Frequency/Microwave (RF/MW) circuit requires the trade-off many importance characteristics such as gain, Noise Figure (NF), stability, power consumption and complexity. This situation Forces the designers to make choices in the design of RF circuits. In this paper the aim is to design and simulate a LNA circuit with high gain and low noise using E-pHEMT MGA665P8 transistor for frequency of 4 GHz. The amplifier is manually designed using conventional technique, Smith chart was used to do a matching of the input and output of the amplifier. The matching network was designed with microstrip lines and it’s single-stub with minimum lengths. A completed design of amplifier was optimized using Hewlett- Packard Advanced Design System (HP-ADS) software. A single stage LNA has successfully designed with 21.032 dB forward gain and 0.697 dB noise figure and working stably in the desired frequency.

Abstract

Tall structures and towers have captivated humans for thousands of years, and so they are a fact of modern life in cities for a variety of reasons. However, the most challenging design problem is meeting operational performance requirements and maintaining occupant comfort. Not only are the site energy costs high, the attendant environmental consequences of using non-renewable energy sources are great. This fact prompted searchers and designers to advance and fully embrace green and environmentally friendly design. One of the key goals of the green building movement and technique is to reduce the material, constructional, and operational costs of buildings. This goal can be accomplished by drawing on the synergies

between building geometry, material usage, and the local climate demands. Architect Ken Yeang, in his famous book The Green Skyscraper, suggests that in different climate zones, they should be arranged in different locations to reduce the yearly energy consumption of the building. But Yeang’s claim of the structural system parameters have clear implications for structural performance since buildings with asymmetric distribution of stiffness are known to be susceptible to damaging torsional modes of vibration when subjected to wind or earthquake loading. Thus, this study performs thermal and structural analysis to address the implications of different footprints and core placements on energy and structural performance. The results demonstrate that to accomplish Yeang's claim, a supplementary lateral load resistance system is needed, which demands additional structural material. As a result, buildings with an asymmetric distribution of stiffness are the most expensive, which has a negative impact on the building's

environmental and economic aspects.

Liquefied Petroleum Gas (LPG) cylinder is a thin pressure vessel used to meet energy requirements in household applications. Bursting of a pressure vessel is disastrous and many fatal accidents are happened due to pressure vessel bursting. The main goal of the current paper is focused to determine experimentally the burst pressures (BP) and failure locations of LPG cylinders. To ensure that the cylinders are in conformance with International Standards. The experiments were carried out on two samples of LPG cylinders used in Libya (C1 and C2). The experimental burst test investigations done by hydrostatic test in which the cylinders were internally pressurized with water. The permanent volume expansions of the LPG cylinders due to internal pressure were also examined. All tests in this study were subject to standard specifications (ISO 4706), which is needed to be conducted on LPG cylinders before introducing them to the Libyan market. Among these tests, the hydro-tests are major tests to be conducted on LPG Cylinders to get approval and acceptance. Hydro-tests on LPG cylinders reveal permanent volumetric expansion of the cylinder, nominal hoop stresses at the time of destruction and the internal pressure at which a cylinder burst. These values are important to ensure that the design and construction of cylinders are safe and compiled to standards.

The main goal of the current paper is focused to investigate and reveal the importance critical

transition temperatures. Different techniques were used to reveal the critical transition temperatures.

The medium carbon vanadium titanium and titanium free micro alloyed steels tested in this work by

isothermal treatment. In order to reveal experimentally the critical forming temperatures and

compare it by predicted using equations and also describe the influence of alloying elements

on the transformation behavior, martensitic starting formation temperature. This study

has been carried out over a wide range of isothermal treatment temperature (270-350

The spread of ICT in education and learning has changed the way of teaching and learning, and

this raised the issue of getting e-learning systems to adapt/personalize with respect to student's

knowledge achievement. However, the relation between the concepts in the programming domain

are not definitive and they are fuzzily related. In this Paper, we describe a practical experience for

developing adaptable e-learning system using fuzzy logic to model and evaluate student's

knowledge for the purpose of adaptation in the field of Computer Programming. Fuzzy logic

technique modeled as a plugin on MOODLE Learning Management System at the Libyan

Academy for Postgraduate Studies is developed. Conclusions highlighted some important lessons

in increasing learning effectiveness and learner's satisfaction.

In this paper, the data filtering based Recursive Least Squares algorithm (RLS) of linear Box–Jenkins systems is proposed for fault detection. The system is decomposed into two subsystems, one containing the parameters of the system model and the other containing the parameters of the noise model to improve the computational load. In addition, the parameters of the system model and the noise model are estimated and their accuracy are developed. The model validation is tested using two statistical methods, histogram and mean square errors. The residual is generated based on the proposed algorithm to design the threshold and therefore, this designed thresholdis used for fault detection. Simulation results are performed to illustrate the algorithm performance.

Abstract

in this paper, (CFD) Computational Fluid Dynamics was used for a detailed burner design by the software Fluent (ANSYS). However, a number of numerical simulations were performed on a generic swirl burner and turbulence flow selection of a non-premixed which using syngas. However, non-premixed flames which characterized by relatively high temperatures, high NOx concentrations, and emission indices. The results showed that the presence of methane in syngas increases the peak flame temperature and the thermal NOx, significantly. Therefore, Investigation showed that effecting of H2, CO, and N2 contents in the fuel mixture level NOx emissions, thus the present compositions for pure methane are respectively influenced on syngas1 by (10% CH4, 45% H2, 45% CO) , syngas2 by (50% CH4, 10% H2, 40%N2) and syngas3 (60% CH4, 20% H2, 20%N2).

This paper aims to design, modeling and manufacturing a prototype composite winding machine used to produce corrugated composite tubes. Seven different types of tubes can be produced: Radial Corrugated Tube (RCT), Radial Corrugated Surrounded by Cylindrical Tube (RCSCT), Cylindrical Tube (CT), Tangential Corrugated Tube (TCT), Tangential Corrugated Surrounded by Cylindrical Tube (TCSCT), Combined Radial and Tangential Corrugated Tube (CRTCT), and Combined Radial and Tangential Corrugated Surrounded by Cylindrical Tube (CRTCSCT). All types can be produced with different size. Although it is designed mainly for composites, however, paper, and thin sheet of metallic materials can be used as raw material too. Different fiber forms can be used such as knitted, woven roving, continuous filament, or chopped mat of glass or carbon fiber. Corrugation profile can be changed to any required shape such as sinusoidal, triangular, square, rectangular, trapezoidal, or combination of any two or more profiles. The machine uses a special technique utilizing a mandrel that can be driven manually as well as automatically. A prototype of a designed machine have been manufactured, and tested. Two different samples of prospected products have been produced successfully.