The impact of cooling water types on the cement clinker properties

This paper studied the influence of the different water types on clinker properties. It concern with cement plants which are using the water for cooling the clinker (El-Minia white cement plant). The water types are Nile, ground and deionized water. The cooling was mad suddenly for clinker by three water types at the same time. The paper discusses the physical and chemical analysis and algal detection of all water types. It also discusses the chemical and physical analysis for kiln feed, clinker. The analysis of water showed that the concentration of dissolved salts in groundwater is higher than Nile water. The concentration of algae gave opposite direction; the algae concentration in Nile water is higher than groundwater. While the deionized is completely free from dissolved salts and algae. The cement tests for clinker which treated by the different water types showed that the cement strength was reducing when used the Nile water with high algae count. From another side, the high concentration of dissolved salts in groundwater does not affect on strength. The water contained the algae prevent the complete crystallization of calcium silicate for clinker. The results also showed that the best type of water, which improved cement compressive strength ranged according to algae count by the sequence deionized water > groundwater > Nile water.     

Finite element analysis of the behaviour of microvoids in the cement mantle of cemented hip stem: Static and dynamic analysis

In this study, the three-dimensional finite element (FE) method is used to analyse the stress distribution around microcavities in the cement mantle of total hip arthoplasty (THA). Static and dynamic loading were analysed. The effect of the position of the microdefect on the stress distribution is also highlighted. The obtained results show that microcavity located in the proximal zone of the prosthesis is subject to higher stress field. The static loading generates higher stresses than dynamic one if the microcavity is located in the proximal and distal zones of the prosthesis. The inverse case is observed when the microcavity is located in the medial zone.     

A parabolic solar cooker with automatic two axes sun tracking system

A parabolic solar cooker with automatic two axes sun tracking system was designed, constructed, operated and tested to overcome the need for frequent tracking and standing in the sun, facing all concentrating solar cookers with manual tracking, and a programmable logic controller was used to control the motion of the solar cooker. The results of the continuous test – performed for three days from 8:30 h to 16:30 h in the year 2008 – showed that the water temperature inside the cooker’s tube reached 90 °C in typical summer days, when the maximum registered ambient temperature was 36 °C. It was also noticed that the water temperature increases when the ambient temperature gets higher or when the solar intensity is abundant. This is in favor of utilizing this cooker in many developing countries, which are characterized by high solar insulations and high temperatures. Besides cooking, the proposed cooker could be utilized for warming food, drinks as well as to pasteurize water or milk.     

Performance analysis of a solar chimney power plant in the southwestern region of Algeria

In this paper, we present the performance analysis of a solar chimney power plant expected to provide the remote villages located in Algerian southwestern region with electric power. Solar energy and the psychometric state of the air in the south of Algeria are important to encourage the full development of solar chimney power plant for the thermal and electrical production of energy for various uses. We are interested in Adrar where solar radiation is better than other areas of Algeria. The obtained results show that the solar chimney power plant can produce from 140 to 200 kW of electricity on a site like Adrar during the year, according to an estimate made on the monthly average of sunning. This production is sufficient for the needs of the isolated areas.     

Analysis and study of two‐dimensional parameter bifurcation of wind power farms and composite loads

This study focuses on the stability of power system based on codimension‐two bifurcation theory. In this paper, we investigate the impact of load modeling on permissible wind power generation margins in distribution networks. The study considers codimension‐two bifurcations of equilibria and limit cycles in wind power systems depending on varying two parameters simultaneously. The principle parameter is the wind power generation, and the other parameter depends on the different types of loads. The types of loads are ZIP, exponential recovery, dynamic induction loads, and composite load models. To study the effects of the induction motor loads, the proportion of the static component in the motor load is changed and assessed with respect to their mechanical loads. Wind generation margin boundaries are traced, and saddle‐node, Hopf, and limit‐induced bifurcation branches are obtained, delimiting the stable and unstable operating regions in the parameter space. The analysis presented in this paper can pave the way for determining methods for improving and monitoring these margins with consideration to the system parameters and load composition.     

Dehumidification of air with a newly suggested liquid desiccant

Calcium chloride solution is a cheap desiccant. It is unstable at certain solution concentrations and dehumidified air temperatures. The aim of this research is to stabilize it by mixing with calcium nitrate in different weight combinations. The physical properties of a proposed liquid desiccant such as density, viscosity, and vapor pressure were obtained. Heat and mass transfer analysis between a thin liquid layer of the proposed desiccant and the air flowing through rectangular channel has been studied. The different factors affecting the dehumidification process of air were studied.     

A New Approach for Optimal Allocation and Economical Capacity of Generation Reserve

Determination of the installed reserve capacity is an essential part of the power system planning. Considering the network limitations, not only the amount of installed reserve capacity, but also the location of this capacity is an essential factor in improving the reliability level of the system. A new appoach to select the most suitable locations for the installed reserve capacity and its distribution between these locations was developed. The problem was formulated as a mathematical programming problem and was efficiently solved using linear programming technique. The optimal reserve capacity in the system was calculated as the amount which minimizes the total system costs, with the capacity added at the preselected locations. The developed approach was applied to the 220 KV system of A.R.E The final results are presented and discussed in this paper.     

Monopolar Corona on Bundle Wires as Influenced by Wind

The measured corona current contributed by each subwire in various laboratory-size bundle models and the total corona current change with wind over a wide range of applied voltages are described. The lateral spacial distribution of the time-average value of windblown corona current over the ground plate is measured for different applied voltages and different bundle geometries. The obtained results are compared to previous findings and to theories of corona discharge.     

Safety assessment methodology in management of spent sealed sources

Environmental hazards can be caused from radioactive waste after their disposal. It was therefore important that safety assessment methodologies be developed and established to study and estimate the possible hazards, and institute certain safety methodologies that lead and prevent the evolution of these hazards. Spent sealed sources are specific type of radioactive waste. According to IAEA definition, spent sealed sources are unused sources because of activity decay, damage, misuse, loss, or theft. Accidental exposure of humans from spent sealed sources can occur at the moment they become spent and before their disposal. Because of that reason, safety assessment methodologies were tailored to suit the management of spent sealed sources. To provide understanding and confidence of this study, validation analysis was undertaken by considering the scenario of an accident that occurred in Egypt, June 2000 (the Meet-Halfa accident from an iridium-192 source). The text of this work includes consideration related to the safety assessment approaches of spent sealed sources which constitutes assessment context, processes leading an active source to be spent, accident scenarios, mathematical models for dose calculations, and radiological consequences and regulatory criteria. The text also includes a validation study, which was carried out by evaluating a theoretical scenario compared to the real scenario of Meet-Halfa accident depending on the clinical assessment of affected individuals.     

Electrical properties of Cu(II) and Ni(II): N-salicylidene polymethacrylic acid hydrazide complexes

Different types of chelated polymer complexes have been synthesized to obtain improved electrical properties. Compact discs from powders of the chelated polymers were prepared and heated in a specially designed holder. Electrical conductivity and dielectric constant of Cu(II) and Ni(II): N-salicylidene polymethacrylic acid hydrazide samples were measured at a fixed frequency (1600 Hz) throughout the temperature range 25-150°C. The AC conductivity as well as dielectric measurements showed maxima at 85°C. The water molecules which were trapped in the polymer matrix are believed to play the main role in conduction and dielectric behaviour of the polymeric material. From the AC conductance and dielectric constant measurements, the dielectric losses of these polymeric materials were calculated as a function of temperature.