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Conductors for most buildings in the UnitedStates are sized using the National Electrical Code (NEC). The 2014 NEC now requires that a value be added to the ambient temperature used to determine the ampacity of conductors installed on rooftops. This paper reports the results of a related experimental test (on both energized and non-energized cables) that is conducted on a rooftop of a building located in the desert southwest during the hottest period of the year. The recorded temperature rise of the conductors tested is compared to the temperature adders specified in the Code. The maximum recorded temperature of the energized conductors is also compared to the rated temperature of the conductor insulation.

In this work, a control system for positioning and stabilizing a massive inertial system subjected to continuous disturbances, which represents the oscillatory motion of the base, is investigated. A hydraulic system is proposed and simulation is used to select and test the effect of different parameters of the hydraulic parts, particularly those of the electro -hydraulic servo valve, at different values of the supply pressure of the hydraulic fluid.The inertial system dynamics and the hydraulic parts are mathematically modeled and simulated by digital computer using (MatLab). The dynamic characteristics of the control system, such as the stability and the time response in addition to the ability of the system to reduce the effect of the external disturbances are examined. The results show that the control system is capable of reducing these effects between (70% to 90%) depending on the supply pressure of the hydraulic system and the frequency of the external disturbances. In addition, the effect of using pressure limit valve in the hydraulic system and that of the presence of dry friction of a relatively high value, are investigated.

Vibrations in rotating system are considered as one of the major operating problems since they have adverse effects on the performance of rotating system, which result in operating life reduction. In this research, the active control of vibration, as a response to mass unbalance, in a rigid rotor symmetrically supported by an oil film bearing is considered. A model of rigid rotor is considered in this study, in which the unbalance mass is positioned out of the plane of the geometrical center of the system. For the cases studied, the active control of system vibration was achieved by the Application of two techniques, namely, pole placement and optimal control techniques, the system dynamics is represented by mathematical models and the system is simulated by a digital computer using Matlab programs. The results obtained showed a high reduction in vibration amplitude, This reduction was more than 80 % and in some situations it raises to more than 90 %.