In Egypt, large quantities of coarse solid wastes are generated during the processing of phosphate ores and quarrying operations of marble and granite rocks. These solid wastes are stored in piles around or near mine sites, which cause many environmental problems. Various solutions have been sought for this major environmental problem and the best solution found is recycling. However these wastes, because of their similarity to the natural aggregate, represent a potentially useful source of material for a variety of applications. The main purpose of this research is to investigate the possibility of utilizing over screen reject generated during phosphate ore processing and rock fragments of quarrying marble and granite rocks in concrete production as full replacement of natural gravel in concrete mix. A number of tests were carried out on these wastes to determine there physical, mechanical and chemical properties, according to the ECP 203 of natural aggregate. So, concrete mixes using the above mentioned wastes as coarse aggregate were done, and then tests for fresh and hardened concrete were carried out. The mean value of uniaxial compressive strength of standard concrete cubes after 28 days of curing was found to be in order of 193 Kg/cm2 for phosphate waste, 262 kg/cm2 for marble waste, and 272 kg/cm2 for granite waste, which approach the conventional concrete used in building. The obtained results proved that these kinds of wastes can be used for concrete mix in civil construction. Admixtures may be used to improve the strength of the first one. The positive uses of these wastes are considered beneficial from the economic and environmental points of view.

Using of false ceilings (FC) for decoration and covering different ducts in modern buildings is spreading so much nowadays. This paper tries to find a new employment and other benefits for using false ceilings (FC).A one dimensional transient mathematical model has been established to study the effects of using false ceiling on reduction of heat gained from concrete roof of controlled temperature space. The effect of using false ceiling (FC), with and without adding reflector sheet on its upper side facing to concrete roof on the room cooling load is studied by modeling and solving the transient heat transfer processes in the different components of the space. The results showed that using of false ceiling only without reflector sheet reduces heatgain introduced to space through 24 hours by 66.8%, while using of false ceiling with reflector sheet increases the reduction percent of heat gained from concrete roof to be 81.6% for the same period.

This paper attempts to investigate the horizontal conductor lightning striking distance estimation. An electromagnetic model was proposed to model a vertical downward lightning leader and an infinite grounded horizontal conductor by using the charge simulation method (CSM) to calculate the lateral striking distance. A formula between the lateral striking distance, the lightning current, and the horizontal conductor height was estimated. The proposed formula was compared with electromagnetic model and previous formulas. By the use of a similar methodology, a horizontal conductor voltage coefficient had been proposed and estimated. The proposed voltage coefficient was used to modify the electrogeometric model in order to study lightning striking rates of an unshielded horizontal conductor for different heights at either AC or DC voltages.

Cyclostationary feature detection is one of the most powerful spectrum sensing techniques used for cognitive radio (CR) systems. This is because of its robustness against noise uncertainties. However, this technique needs high sampling rates, which is limited by the state-of the-art analog to digital converters (ADCs), especially in wideband regime. Comressive sensing (CS) was used by many researchers for solving this problem via sub-Nyquist sampling rates. However CS solves the high sampling rate problem, but it does not reduce complexity considerably. This is because spectrum sensing is performed in three steps: sensing compressed measurements, then reconstructing the Nyquist rate signal, and finally performing cyclostationary detection (CD) on the reconstructed signal. In this paper we suggest performing CD directly on the compressed measurements skipping the reconstruction step which is the most complex step in CS. This can be realized by designing the sensing matrix with constraints different from those used in the conventional CS. Results show that performance is improved relative to applying CD on the Nyquist rate signal. This is in addition to reduction in receiver complexity resulting from reducing sampling rates. A detection probability of 78.7% can be achieved with only 7% of samples used by the conventional cyclostationary detection technique that achieves a detection probability of 32.7%.

Cyclostationary feature detection is one of the most powerful spectrum sensing techniques used for cognitive radio (CR) systems. This is because of its robustness against noise uncertainties. However, this technique needs high sampling rates, which is limited by the state-of the-art analog to digital converters (ADCs), especially in wideband regime. Comressive sensing (CS) was used by many researchers for solving this problem via sub-Nyquist sampling rates. However CS solves the high sampling rate problem, but it does not reduce complexity considerably. This is because spectrum sensing is performed in three steps: sensing compressed measurements, then reconstructing the Nyquist rate signal, and finally performing cyclostationary detection (CD) on the reconstructed signal. In this paper we suggest performing CD directly on the compressed measurements skipping the reconstruction step which is the most complex step in CS. This can be realized by designing the sensing matrix with constraints different from those used in the conventional CS. Results show that performance is improved relative to applying CD on the Nyquist rate signal. This is in addition to reduction in receiver complexity resulting from reducing sampling rates. A detection probability of 78.7% can be achieved with only 7% of samples used by the conventional cyclostationary detection technique that achieves a detection probability of 32.7%.

Cyclostationary feature detection is one of the most powerful spectrum sensing techniques used for cognitive radio (CR) systems. This is because of its robustness against noise uncertainties. However, this technique needs high sampling rates, which is limited by the state-of the-art analog to digital converters (ADCs), especially in wideband regime. Comressive sensing (CS) was used by many researchers for solving this problem via sub-Nyquist sampling rates. However CS solves the high sampling rate problem, but it does not reduce complexity considerably. This is because spectrum sensing is performed in three steps: sensing compressed measurements, then reconstructing the Nyquist rate signal, and finally performing cyclostationary detection (CD) on the reconstructed signal. In this paper we suggest performing CD directly on the compressed measurements skipping the reconstruction step which is the most complex step in CS. This can be realized by designing the sensing matrix with constraints different from those used in the conventional CS. Results show that performance is improved relative to applying CD on the Nyquist rate signal. This is in addition to reduction in receiver complexity resulting from reducing sampling rates. A detection probability of 78.7% can be achieved with only 7% of samples used by the conventional cyclostationary detection technique that achieves a detection probability of 32.7%.

Optimal computation of parameters and placement of UPFC based minimization of New Voltage Stability Index (NVSI) are presented in this paper. The application of Unified Power Flow Controller (UPFC) to enhance transient stability of a multi-machine power system is listed. A supplementary stabilizer based on UPFC (like power system stabilizer) is designed to reach the defined purpose. Phase Angle Particle Swarm Algorithm (θ-PSO) is usedas an optimization method. Several nonlinear time-domain simulation tests visibly show UPFC capability in damping of power system oscillations and consequently transient stability betterment. Comparisons based system transient stability enhancement among different UPFC locations and parameters are introduced. The effectiveness of the proposed method is analyzed with IEEE 14-bus and IEEE 30-bus test systems.

Using of false ceilings (FC) for decoration and covering different ducts in modern buildings is spreading so much nowadays. This paper tries to find a new employment and other benefits for using false ceilings (FC).A one dimensional transient mathematical model has been established to study the effects of using false ceiling on reduction of heat gained from concrete roof of controlled temperature space. The effect of using false ceiling (FC), with and without adding reflector sheet on its upper side facing to concrete roof on the room cooling load is studied by modeling and solving the transient heat transfer processes in the different components of the space. The results showed that using of false ceiling only without reflector sheet reduces heatgain introduced to space through 24 hours by 66.8%, while using of false ceiling with reflector sheet increases the reduction percent of heat gained from concrete roof to be 81.6% for the same period.

Retrofitting the seismically deficient structures before earthquakes provides a feasible approach to improve their load carrying capacity and reducing their vulnerability. This study presents an analytical assessment investigation on hollow block slab reinforced concrete building. The building is not designed according to seismic standards; moreover, hollow block slab systems may lack the sufficient lateral seismic resistance. Different retrofitting systems to enhance the seismic capacity of the target building are proposed and evaluated. These systems include strengthening the columns with reinforced concrete jackets or using internal shear walls or introducing steel chevron bracing. The target building before and after retrofitting is analyzed either as bare frames or considering masonry infill walls with different parameters. The three dimensional nonlinear pushover analysis procedures are used in evaluating the seismic performance of the original building and the retrofitted ones. The demand response spectra proposed by the Egyptian Code of Loads, ECOL 201, 2012 edition, for different seismic zones with different soil properties are utilized in the evaluation. Real seven earthquakes response spectra with maximum-scaled spectrum acceleration close to the one calculated for Cairo city are also applied. It is found that the original target building, before retrofitting, fails to fulfill the demands of neither many of the ECOL response spectra nor many of the applied real earthquakes. All the proposed retrofitting systems succeed in highly enhancing the seismic capacity of the original building. Considering masonry infill walls in the analysis has a crucial role on the seismic performance of the original building, the retrofitting systems can, due to the increase in the lateral strength, limit this effect.

Using of false ceilings (FC) for decoration and covering different ducts in modern buildings is spreading so much nowadays. This paper tries to find a new employment and other benefits for using false ceilings (FC).A one dimensional transient mathematical model has been established to study the effects of using false ceiling on reduction of heat gained from concrete roof of controlled temperature space. The effect of using false ceiling (FC), with and without adding reflector sheet on its upper side facing to concrete roof on the room cooling load is studied by modeling and solving the transient heat transfer processes in the different components of the space. The results showed that using of false ceiling only without reflector sheet reduces heatgain introduced to space through 24 hours by 66.8%, while using of false ceiling with reflector sheet increases the reduction percent of heat gained from concrete roof to be 81.6% for the same period.