Rock mass classification systems consider one of the design tools, which are used in conjunction with engineering assessments and other design approaches. There are many classification systems, which are widely employed in rock engineering. In this study one of these systems is used for the selection of the optimum panel width in phosphate mine Abu Tartur area. Geological Strength Index (GSI) is one of these systems which enables for calculations of the panel width. Data for the GSI system are obtained from geological reports, some field measurements and laboratory tests. The obtained panel width (wall length) for Abu-Tartur area is calculated to be about 100m (102m) which differs strongly from the applied length in the area (150m). So, it is recommended to apply this obtained length to secure safe mining conditions without roof falls which is the main problem facing underground mining in this area.

This paper presents a comparative experimental study on the performance characteristics of the circulating air coolers for the generators of the hydro-power plant of the High Dam in Aswan. The study considers two different air-water cooler designs of cross flow finned tubes heat exchangers working under varying operating conditions. The circulating air temperatures and the cooling water pressures for twelve coolers in each of the twelve units of the hydro-power plant were measured and analyzed to obtain useful results describing the cooler performance. The experimental results are based on measurements over total time duration of 1008 operating hours covering 42 summer days. The results are discussed to investigate the effects of time variation of the generated power, and the locations of the coolers and the power units on the performance of both cooler designs. The results of the actual fouling factor indicate that both coolers were designed with excess surface area to work well for long periods. The agreement of the experimental results with the commonly used effectiveness empirical relation indicates the proper performance of the working coolers. On the other hand, the discussion of the results showed the malfunction of some coolers due to the blockage of their damaged tubes. The overall performance of the air coolers in most power units of the plant maintains good flow behaviour of the hot air and uniformity of its temperature at levels sufficiently below the normal design temperature range for the generators of most power units.

Modeling and simulation of production lines is considered to be important for designers who are interested in: Work-load Allocation Problem (WAP), Server Allocation Problem (SAP), and Buffer Allocation Problem (BAP). This paper studies and analyzes a real cement production line as a case study. A simulation model is developed by ARENA software and used to analyze and test several bottlenecks that are causing severe congestions in different areas on the production line and could resolve all of these bottlenecks. Workstation failure data is collected along one year to obtain the machines failure behaviors. This paper searches for the optimum buffer sizes with the increase of the production rate. An actual cement production line is studied and analyzed by the simulation model from stem to stern. After a simulation replication time of 12 days, a simulation results show the line bottlenecks, workstations utilization, buffer capacities and the line production rate. To resolve the bottlenecks, a redesign of allocation of buffers which verify an optimum size could be made and it might be taken into consideration when designers implement this line. Finally modified optimum workstations utilization, buffer capacities and the line production rate with an increase about more than 15% of the production rate and economizing of 34 % of buffer capacities.

Modeling and simulation of production lines is considered to be important for designers who are interested in: Work-load Allocation Problem (WAP), Server Allocation Problem (SAP), and Buffer Allocation Problem (BAP). This paper studies and analyzes a real cement production line as a case study. A simulation model is developed by ARENA software and used to analyze and test several bottlenecks that are causing severe congestions in different areas on the production line and could resolve all of these bottlenecks. Workstation failure data is collected along one year to obtain the machines failure behaviors. This paper searches for the optimum buffer sizes with the increase of the production rate. An actual cement production line is studied and analyzed by the simulation model from stem to stern. After a simulation replication time of 12 days, a simulation results show the line bottlenecks, workstations utilization, buffer capacities and the line production rate. To resolve the bottlenecks, a redesign of allocation of buffers which verify an optimum size could be made and it might be taken into consideration when designers implement this line. Finally modified optimum workstations utilization, buffer capacities and the line production rate with an increase about more than 15% of the production rate and economizing of 34 % of buffer capacities.

In the present study, an investigation of the effect of using acetic acid (CH3COOH) in condenser de scaling on the exhaust emissions and the performance of Assiut Thermal Power Plant. Efficient condenser operation maintains turbine efficiency; benefits consumers by reducing the amount of emissions. Condenser vacuum has a great effect on the unit efficiency to a degree that it reduces the generated load by 112 MW (35.9%) in unit one of Assiut Power Plant and to the extent that cleaning became very necessary. From environmentally point of view an organic, biodegradable, locally produced, effective and cheap de-scaling agent was the very applicable one and this meet with acetic acid. Actually, condenser cleaning leads to an improvement in the turbine efficiency and raises the maximum load generated from the unit (from 200 MW before cleaning to 290 MW after cleaning), decreases fuel consumed for MW (from 249 kg/MWh at load 200 MW to 220 kg/MWh at load 290 MW), reduces the overall fuel consumption, consequently, reduces emissions as CO, CO2, SOx, NOx, ground level ozone, PM, VOC, ashes, solid deposits, haze, thermal pollution, and reduces contribution to global warming, heat island effect at Assiut city. In brief, the condenser cleaning process reduces the environmental pollution from the unit which in turn minimizes the health impact of these pollutants.

Modern industrial operations wouldn't accept old defects to be present in the new products, especially that many products include electronic parts or connections that are very sensitive to the level of finish. Burr formation in drilling operations causes products to be rejected or sent for deburring. Since deburring is a costly and non-value-added operation, the understanding and control of burr formation is a research topic with high relevance to industrial applications. In order to investigate and improve burr formation, a spring was mounted over the bench drill spindle to measure the cutting force and attempt to know its influence on the burr outcome of the operation.

Radio Frequency Identification (RFID) has received recently a great attention from large organizations and researchers due to the dropping tag costs and vigorous RFID standardization. They are becoming more common in daily use to identify, locate and track people, assets, and animals. Number of protocols has been proposed in the literature for the security of RFID against passive attacks. One of the well-known protocols is the HB family protocol which utilizes the complexity of decoding linear codes for RFID security against passive attacks. The nonlinear HB (NLHB) is one member of the HB family protocol which achieves high security by reducing the provably hard problem of decoding a class of nonlinear codes to passive attacks. This paper introduces Multi-Nonlinear Stages to the HB protocol to enhance its security against passive attacks. More specifically, the paper presents two Multi-Nonlinear versions of the HB protocol; Double-Nonlinear HB (DNLHB), and Triple-Nonlinear HB (TNLHB). The proposed protocols increase significantly the security of RFID systems against passive attacks at a lower implementation cost.

The macro-models method is one of the main categories for modeling infills based on the equivalent strut method. The basic parameter of these struts is their equivalent width, which affects the stiffness and strength. This paper presents a general review of several expressions proposed by researchers to calculate this equivalent width. The comparative study of different expressions shows that the Paulay and Priestley equation is the most suitable choice for calculating the diagonal equivalent strut width, due to its simplicity and because it gives an approximate average value among those studied in this paper. Consequently, the model will be used in our further study for analysis of RC infilled frames.

The macro-models method is one of the main categories for modeling infills based on the equivalent strut method. The basic parameter of these struts is their equivalent width, which affects the stiffness and strength. This paper presents a general review of several expressions proposed by researchers to calculate this equivalent width. The comparative study of different expressions shows that the Paulay and Priestley equation is the most suitable choice for calculating the diagonal equivalent strut width, due to its simplicity and because it gives an approximate average value among those studied in this paper. Consequently, the model will be used in our further study for analysis of RC infilled frames.

During recent years, Egypt water treatment plants allocated on the banks of River Nile have faced few accidents of hydrocarbon spills into the River which forced the operators to shout down many plants from Aswan to Cairo. Nevertheless, water supply applying the natural and low-cost technique called riverbank filtration "RBF" has been used worldwide. For more than 100 years, RBF that has been used in Europe for public and industrial water supply along Rhine, Elbe, and Danube rivers. In RBF method, the surface water contaminants are removed or degraded as the infiltrating water moves from the river or lake to the abstraction wells. Physical, chemical, and biological treatment processes occur during this technique. In this work, RBF site which is located in east bank of river Nile at Upper Egypt was investigated. This site was established to supply potable water to the construction staff of about 3000 residents, of the new Naga Hammadi Barrage, Qena governorate. It consists of two productive wells of 55 m depth located at 100 m apart from River Nile. No further treatment processes were used except disinfection applying chlorine as calcium hypochlorite. Water samples from abstraction wells were collected for physiochemical and microbiological measurements. Quality analysis of the samples indicates that the produced water using RBF technique complies with allowable standards for drinking purposes. The results have proven RBF effectiveness for water supply from river Nile in Upper Egypt and motivate its integration with tradition plants to secure water supply from Nile during the chemical pollution of Nile.