The paper presents studies on experimental investigation of beam-to-column joint behaviour in standard and exceptional events situations. This assessment is done to form a picture of the general the behavior of full scale frameworks at both the level of the global behavior of the framework, in terms of its load-displacement characteristic, and of the local behavior of joints in terms of their moment-rotation characteristics, and evaluates details about the interaction of the joint elements and how they work together in a balanced manner, during exceptional events, this study concerns the joints which are subject to the collapse and also includes the behavior of joints in the neighborhood of the collapse. The intricacy of such investigations appear from nonlinear effects associated with the outlook of joint behavior or functioning, such as structural shortcomings, large displacements and rotations, inelastic properties of steel and concrete materials, the effects between steel and concrete, and slip between concrete and structural steel, through others. The paper addresses these problems using two types of joints flush and extended end-plate with four and eight bolts and provides recommendations and reasoning for the behavioral techniques for the evaluation of joint moment-rotation response when exposed to negative and positive moments together.

АННОТАЦИЯ:

Through the last three decades, the Normalized Difference Vegetation Index (NDVI) has been widely used for vegetation mapping and monitoring land-cover change in semi-arid regions. In Libya semi-arid lands occupy many parts in the north part of country that is near the Mediterranean Sea. The aim of paper is to use remote sensing technique (NDVI) for monitoring vegetation degradation in Al-Jabal Al-Akhdar region in Libya. The Pathfinder AVHRR Land (PAL), SPOT Apparent green cover percentage data and MODIS Vegetation index are used to monitor the vegetation cover change in the study area. The paper explain the possibility of use only long term NOAA-AVHRR NDVI time-series data, without need to any precipitation data, for assessing desertification conditions in Al-Jabal Al-Akhdar region. According to annual rainfall the northern parts of the area receives the greatest amount of rainfall towards the Mediterranean Sea, which occurs between October and May, it agreed well with the spatial pattern of NDVI within monthly averaged of vegetation that start increasing rapidly and reached a greater amount during spring (March-May), and decreased during June to September...

In this work, the estimation capacity of the response surface methodology (RSM), in the catalytic naphtha reforming to enhance the octane number of reformats via isomerization reaction pathway and minimize the aromatization activity over tri-metallic modified Pt-Re/Al2O3 catalyst were investigated by applying Design of experiment (DOE). The parent bimetallic catalysts were modified using a relatively inactive metal (Sn) by means of employing non-conventional method of anchoring technique called controlled surface reaction (CSR) method in order to favor the intimate contact of Sn with the active phase to suppress the metallic character of Pt metal. The correlations between RON, aromatization and isomerization activities with three reaction variables namely temperature (480-510oC), pressure (10-30 bar) and space velocity LHSV (1.2-1.8 h-1) were presented as empirical mathematical models via reforming of a complex mixture (80oC -185oC). Numerical results indicated that the minimum aromatization activity was 20% when reaction temperature was 460oC and pressure of 35 bar. Results also show that maximum isomerization activity of 58% was achieved when pressure is 30 bar and space velocity is 1.8 h. it has been found that optimum value of RON = 89 was attained at 449.9oC, 32 bar and 1.7 h-1. However, high operating pressure and low reaction temperature significantly decrease the aromatization activity coupled with substantial decrease in RON which can be enhanced by producing high yield of isomers.  

It has become firmly established the productivity is the real source of and important for economic growth of any country; it has an essential role in the economies of developed and developing countries alike. It allows the nation to raise its standard of living, to support such social goals as education and health care, and to contribute to other aspects of the general welfare; it is an essential underpinning of the nation's security (Stupak and Leitner, 2001). Increased productivity is the key to economic progress, where the standard of living of communities and income levels depend on the progress of the level of productivity; higher levels of productivity in economies lead to increased rates of growth and prosperity (Seid, 1996).

This work is a continuation of a design of a phase radio navigation system for aircraft blind landing in case of nonequipped runways proposed in [1], where, the proposed system is based on measuring the phase shifts of signals received from four ground transmitters (antennas), placed on corners of the runway strip, which provide distance measurements accuracy in millimeters. However, there are two important points that need serious consideration. First, the phase measurement is going to give the total phase () ϕ ρ−

0, while the actual phase shift of interest is ‘ϕ’, 0 ρ is the transmitter initial phase. The second problem is that, the measured phase angle () ϕ ρ− 0 between the transmitted and the received signal can only be measured in the interval from 0 to π 2 radians, this problem is called phase ambiguity. The answer of these problems lies in the use of more than one frequency (signal). Two sinusoidal signals with different frequencies (1f and 2f) but the same initial phase can be used. Taking the difference of the measured phases, the initial phase 0 ρ can vanish. To get around phase ambiguity would be to make sure that the actual phase difference 12 ϕ∆ does not exceed π 2, this technique called equivalent or synthetic wavelength.

A new radio navigation system for aircraft blind landing is proposed. This system is based on measuring the phase shifts of signals received from four ground transmitters (antennas), placed on corners of the runway strip. The received signals phase shifts provide distance measurements accuracy in millimetres. The reception of these signals is made on the onboard antenna located on the aircraft. Three ground antennas out of the four will be sufficient for determining the location of the aircraft. As a result of the analysis, the coordinates of the onboard antenna, the coordinates of the centre of mass of the aircraft, and axis coordinate of the aircraft determined with respect to the runway coordinate system.