Engineering, Technology & Applied Science Research

467-472

Authors: S. F. Mekhamer, A. Y. Abdelaziz, S. M. Ismael

Power system harmonics may cause several problems, such as malfunctions of electrical equipment, premature equipment failures and plant shutdowns. Accordingly, mitigation of these harmonics is considered an important target especially for industrial applications where any short downtime period may lead to great economic losses. Harmonic analysis studies are necessary to analyze the current and voltage harmonic levels and check if these levels comply with the contractual or international standard limits. If the studies reveal that the preset limits are exceeded, then a suitable harmonic mitigation technique should be installed. Harmonic analysis studies in the industrial electrical systems are discussed in many references. However, a comprehensive procedure for the steps required to perform a harmonic study is rarely found in the literature even though it is strongly needed for design engineers. This paper provides a comprehensive procedure for the steps required to perform a harmonic study in the form of a flowchart, based on industrial research and experience. Hence, this paper may be considered as a helpful guide for design engineers and consultants of the industrial sector.

479-482

Authors: F. B. Mainier, L. P. C. Monteiro, R. J. Mainier

The pollutants found in emissions from cement plants depend on the processes used and the operation of the clinker kilns. Another crucial aspect concerns the characteristics of raw materials and fuels. The intensive use of fuels in rotary kilns of cement plants and the increasing fuel diversification, including fuels derived from coal and oil, from a multitude of industrial waste and from biomass, charcoal and agricultural waste (sugarcane bagasse, rice husk), is increasing the possibilities of combinations or mixtures of different fuels, known as blends. Thus, there are socio-environmental impacts associated with the burning of alternative fuels in clinker kilns. In view of the growing trend of entrepreneurs who want to target the waste produced in their unit and of the owners of the cement plants who want to reduce their production costs by burning a waste with lower cost than conventional fuels, it is necessary to warn that a minimum level of environmental care should be followed regarding these decisions. It is necessary to monitor the points of emission from cement kilns and in the wider area influenced by the plant, in order to improve environmental quality. Laboratory studies of burning vulcanised rubber contaminated with arsenic simulate the burning of used tires in cement clinker kilns producing SO2 and As2O3.

488-496

Authors: F. Khelil, B. Aour, M. Belhouari, N. Benseddiq

Materials fatigue is a particularly serious and unsafe kind of material destruction. Investigations of the fatigue crack growth rate and fatigue life constitute very important and complex problems in mechanics. The understanding of the cracking mechanisms, taking into account various factors such as the load pattern, the strain rate, the stress ratio, etc., is of a first need. In this work an energy approach of the Fatigue Crack Growth (FCG) was proposed. This approach is based on the numerical determination of the plastic zone by introducing a novel form of plastic radius. The experimental results conducted on two aluminum alloys of types 2024-T351 and 7075-T7351 were exploited to validate the developed numerical model. A good agreement has been found between the two types of results.

502-505

Authors: K. A. Venkataraman, K. Kanthavel, B. Nirmal Kumar

In pneumatic circuits, a solenoid valve is a key component for controlling and directing pneumatic energy. The solenoid valve functional performances are defined as response time parameters with respect to its actuations in terms of direction changing time. This paper aims to present response time parameters of solenoid valves under various working pressures. An experimental setup is employed in order to measure response time with reference to the input signals. The response time plays significant role for evaluating the valve performance in sensitive applications. The response time parameters includes the on delay, the off delay, the on time, the off time, the cycle time and the switching frequency. In this experimental investigation the influence of various input pressure conditions is recorded and tabulated. Valves with varying orifice diameter are employed and the investigation reveals the influence of orifice diameter in response time variations. The newly-proposed six response time parameters can be used to rate and select the appropriate valve for various industrial applications.