Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
EFFECT OF LOCAL METAKAOLIN ON PROPERTIES OF CONCRETE AND ITS SULPHURIC ACID RESISTANCE
183
199
EN
Mohamed M.
Rashwan
staff in Civil Engineering Depart., Faculty of Engineering, Assiut University, Assiut, Egypt
Abdel Rahman
Megahed
staff in Civil Engineering Depart., Faculty of Engineering, Assiut University, Assiut, Egypt
Mohamed Sayed
Essa
Civil Engineer, Zagazzige University, 2005
engasmanty@yahoo.com
10.21608/jesaun.2015.115165
Recently, there is an energy crisis in Egypt. The Portland cement industry is a highly energy intensive process requiring about 112 k.w of energy-per ton of finished product. Therefore, the efforts should be made to find alternatives for Cement. Supplementary cementing materials (SCM) play an important role in the production of high strength and high performance concrete. In recent years worldwide, metakaolin (MK) has been studied because of its high pozzolanic properties. MK is obtained by the calcination of kaolinite. The raw material input in the manufacture of MK is kaolin. Although Egypt have a large reserve of kaolin however, MK is not widely produced and used due to the lack of adequate experiments. Therefore in these study local kaolins was thermally treated at specified conditions at 750˚C for three hours to produce what so-called MK material.<br />This study investigates the influence of using two types of local metakaolin as supplementary cementing material on properties, strength and durability of concrete and compared with the performance of ordinary (control) and silica fume. The experimental study was carried out in two stages. The first stage consists of 14 concrete mixes from the two obtained types of metakaolin, MKA and MKB and in addition to silica fume (SF) with various percentage (8%, 12%, 15% and 20%) as partial replacement by cement weight to study fresh properties of concrete in terms of unit weight, compacting factor and slump (Superplasticizer Dosage), as well as the hardened properties in terms of compressive strength, water absorption and Porosity. The second stage in this research, investigated the effect of two metakaolins and comparing with silica fume as well as type of cement on concrete resistance to 3% sulphuric acid attack by measuring the percentage of mass loss and percentage reduction in compressive strength after 30, 60 and 90 days of acids immersion.<br />Results show that similar to silica fume, Egyptian metakaolin can be considered as an effective pozzolanic mineral admixture where, metakaolin replacement of cement is effective in improving the fresh and mechanical properties of concrete. The optimum dosage of metakaolin, as a partial cement replacement is 15 to 20% for the used fineness in this study at W/Cm ratio 0.4. It achieves an increase in compressive strength by 25% as compared to control ones, as well as it has the lowest water absorption. A beneficial effect was found by incorporating combination of two admixtures 20% silica fume with 15% metakaolin on concrete sulphuric acid resistance.
Supplementary cementing materials,Metakaolin,high pozzolanic properties,silica
https://jesaun.journals.ekb.eg/article_115165.html
https://jesaun.journals.ekb.eg/article_115165_70dc53c196b6cde2c03c572fce86831d.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
A LINEARIZATION TECHNIQUE FOR NONLINEAR SDOF SYSTEMS BASED ON BLOCK PULSE TRANSFORM
200
210
EN
Hosein
Ghaffarzadeh
Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran
10.21608/jesaun.2015.115166
This paper addresses a linearization technique for a single degree of freedom (SDOF) linearizable<br />nonlinear system based on block pulse (BP) transform. The BP transform gives effective tools to<br />simplify control and system problems. The main goal of this work is on using BP transform<br />properties in process of linearization of nonlinear problems. It is necessary to compare the results<br />obtained using this method with other traditional methods to verify the effectiveness of the proposed<br />method. The efficiency of BP transform method compared with the traditional equivalent<br />linearization (EL) method. Both numerical simulations are applied to the Duffing nonlinear<br />oscillator system to demonstrate the feasibility of the proposed method based on BP transform.<br />Finally, the results of the comparison between the approaches depicted the proposed method is able<br />to approximate the nonlinear systems behavior. The results showed the superiority of the proposed<br />approach in the sense that it is more accurate by computational advantageous.
Linearization,block pulse transform,nonlinearity,Duffing oscillator
https://jesaun.journals.ekb.eg/article_115166.html
https://jesaun.journals.ekb.eg/article_115166_e50a59569b17f60879bae7afe6da06d5.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
FURTHER CONTRIBUTION FOR EVALUATING THE AGING OF TRANSFORMER OIL OF POWER TRANSFORMER
211
226
EN
Sobhy S.
Dessouky
Electrical Power and Machines Department. Port Said University, Port Said
Adel
El Faraskoury
Extra High Voltage Research Centre, Egyptian Electricity Holding Company, Cairo, Egypt
Sherif
Ghoneim
Electrical Power Department, Suez University, Suez
Ahmed
Haassan
Electrical Power Department, Suez University, Suez
egypt.doctorelectricity@gmail.com
10.21608/jesaun.2015.115168
Transformers are essential parts in the power system for voltage level conversion and maintaining the power flow in the electrical power system, the stability of which is significant for the reliability of the whole supply. The oil used in all transformers is used for insulating and cooling purposes. Degradation of transformer oil occurs because of the ageing, high temperature and chemical reactions such as the oxidation. It is also affected by contaminants from the solid materials. Therefore, the oil condition must be checked regularly and reclaimed or replaced periodically, to avoid the sudden failure of the transformer. In this paper, breakdown voltages (BDV) as well as dielectric dissipation factor (Tan δ) at some different oil conditions are measured. The effect of temperature variation, particle existence in the oil and the water content are studied. The results explain that the aged oil at 80oC (heated for two hours) provides a good dielectric strength than that fresh oil. The particles in the oil play an important part for decreasing the BDV as well as giving worst value of tan δ.
Transformer,mineral oil,Breakdown Voltage (BDV),Dielectric Dissipation Factor (tan δ),and water content
https://jesaun.journals.ekb.eg/article_115168.html
https://jesaun.journals.ekb.eg/article_115168_8f3d132b6e36e62c8160492fd139a12c.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
DIRECT SEQUENCE DATA SEPARATION USING ADAPTIVE BLIND DECONVOLUTION
227
241
EN
Gamal M. M.
Abdel Rahem
Electrical Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt
Usama
Sayed Mohammed
Electrical Engineering Department,Faculty of Engineering,Assiut University,
Assiut, Egypt
usama@aun.edu.eg
Khaled S.
Sherif
Electrical Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt
10.21608/jesaun.2015.115169
Direct sequence spread spectrum (DSSS) signal is generated by modulating the pseudo random<br />noise (PN) sequence with the data signal. The receiver must generate the same PN sequence to<br />extract the direct sequence signal and then get the data signal. This paper presents a method to<br />separate the PN sequence and data sequence from DSSS signal using adaptive blind deconvolution<br />technique which utilizes the normalized cumulant of the adaptive signal. To minimize the<br />computation burden the process gain is first estimated and is used in the adaptation process. The<br />process gain estimator is also based on the computation of the normalized cumulant. Moreover, an<br />efficient method that can enhance the direct-sequence spread spectrum (DSSS) signal at the receiver<br />is introduced without complicating traditional slipping and tracking schemes. Both theoretical<br />analysis and computer simulations verify the validity of the proposed method.
Code division multiple access,pseudo-noise codes,maximal length,Gold,Barker,Code Tracking,Direct sequence spread spectrum,adaptive blind deconvolution,process gain,cumulant
https://jesaun.journals.ekb.eg/article_115169.html
https://jesaun.journals.ekb.eg/article_115169_d728e828863e889cad430b10128428d4.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
ALL OPTICAL OVSF CODE GENERATOR REALIZATION USING OPTICAL FLIP FLOP AND OPTICAL HARDLIMITTERS
242
252
EN
Tamer
A. Moniem
Canadian International College CIC, New Cairo, Egypt
tamer_abdelrahman@cic-cairo.com
Noha
EL Mosilhy
Canadian International College CIC, New Cairo, Egypt
10.21608/jesaun.2015.115171
The orthogonal variables spreading factor (OVSF) provides variables data rates to flexible support<br />many applications with different bandwidth. This paper presents an optical OVSF code generator<br />using all optical gates and a set of all optical flip-flops based on two coupled polarization switches<br />(PSWs). The optical OVSF code generator helps to use the OVSF code technique in optical<br />communications. The general objective is to make the OVSF code tree suitable to support a lot of<br />users in the optical communication links. The overall design and the results are discussed through the<br />realization and the computing numerical simulation to confirm its operation and feasibility. The<br />proposed scheme has been theoretically demonstrated for a spreading factor of 4 and 8.
Optical Flip Flops,optical gates,Bragg Grating,OVSF,SOA
https://jesaun.journals.ekb.eg/article_115171.html
https://jesaun.journals.ekb.eg/article_115171_59a07200cd5eb440687e76e7f95d4045.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
PARAMETRIC STABILITY ANALYSIS OF ROOM AND PILLAR METHOD IN DEEP COAL MINES
253
262
EN
Wael Rashad Elrawy
Abdellah
0000-0001-8133-7817
Mining & Metallurgical Eng. Dept., Faculty of Engineering- University of Assiut, Assiut, Egypt
waelabdellah@aun.edu.eg
10.21608/jesaun.2015.115172
The goal of this paper is, to examine the validity of tributary area method, which is used as an empirical mean to estimate pillar dimensions, in room and pillar mines, taking into consideration a safety factor. A two-dimensional, linear elastic, finite element model (Phase 2D) is created for a simple case of a uniform pattern of room and pillar mine layout, that is lying flat 1200 m below ground surface. Sensitivity analysis has been done to study the effect of horizontal-to-vertical stress ratio, K, on the maximum stress that pillar can sustain without failure. Four cases have been presented in this investigation (K = 0.5, 1, 1.5 and 2). The results reveal that, the maximum stress on the pillar increases as K increases. Alternatively, factor of safety deteriorates as mining depth (i.e., increase of K-value) increases. The results also show that displacements/convergence expand as mining depth goes down.
Haulage drift,Stability indicators,Numerical modelling,Mining Step
https://jesaun.journals.ekb.eg/article_115172.html
https://jesaun.journals.ekb.eg/article_115172_36482e0cc19aa15dc5ba7e4b6f673972.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
DESIGN EVALUATION FOR HOUSING UNITS AT PRINCE SALMAN * ASSOCIATION FOR CHARITABLE HOUSING IN RIYADH
263
281
EN
Ahmed
Ghamdy
Moussad
Abdallah
10.21608/jesaun.2015.115174
Through the large number of charity housing projects that have been implemented in Riyadh over<br />the past years it was necessary to conduct an evaluation study to determine the satisfaction of<br />beneficiaries for the design of the housing units in these charitable projects. King Salman<br />Association for charity Housing has been selected as a case study for this study due to its largest<br />number of charitable housing projects constructed in Riyadh.<br />This research comes due to differences in the design of charity housing units in spite of the similarity<br />of beneficiaries characteristics، and the study aims to measure the degree of satisfaction of necessary<br />needs for those who dwell in the charity housing units in order to know the basic requirements that<br />effects on the level of satisfaction so that it can be provided in future residential units.<br />The study was conducted to measure the satisfaction of beneficiaries for the design of their<br />residential units by comparing between the association's projects in Riyadh (the first compound، the<br />second compound، the third compound، and the fourth compound). The research methodology is<br />divided into two parts: first، the literature review of techniques and methods to measuring<br />satisfaction in housing projects in both global and local cases. Second، is a field study by comparing<br />the satisfaction of the four residential compounds that have been run in the city of Riyadh by<br />comparing scores of satisfaction among the various housing units models. The study showed results<br />to be taken into consideration when designing future housing units as the number of spaces، the area<br />and its relations with each other، visual efficiency to interfaces، environmental aspects of the unit،<br />psychological comfort، and privacy.
https://jesaun.journals.ekb.eg/article_115174.html
https://jesaun.journals.ekb.eg/article_115174_a8672f5ba9fcf15f874d196b9070ca27.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
TEACHING WITH INFLUENCE: AN ANALYSIS OF TEACHING METHODS USED AT THE COURSE OF CONTROL SYSTEMS IN BUILDINGS
282
294
EN
Laila M.
Khodeir
Faculty of Engineering, Cairo, Egypt
10.21608/jesaun.2015.115176
The course of the control systems in buildings was an elective course offered to junior students in credit-hour system at Ain Shams University in Egypt .The course aimed at providing students, who are not energy experts, with a tool that enables them to use energy consequences in designing sustainable buildings, in addition to enhancing critical thinking. To fulfill the course objective, a group of non-systematic teaching methods were applied. Thus the main goal of this paper is examining the application of a group of methods, in environmental design education, to promote critical thinking, to go beyond the limits of academic teaching and to influence students while creating an effective learning environment. This approach is fulfilled through the analysis of the course entitled: “Control Systems in Buildings”, where different teaching methods, techniques and tools were adopted, including debate, case studies analysis, mind mapping, teamwork and various decision-making techniques. The main challenge was that these students were not architecture specialists, as their curriculum concentrates on other issues including civil works and management, in addition to environmental courses. The paper conducted analyses of the case study of the course, where the tasks performed by students, together with an evaluation of their satisfaction with the course and its overall impact on their environmental awareness, choices and exam results were analyzed. The results of this analysis, though very beneficial to any instructor working in the field of environmental education, should be limited to elective courses including a small number of students, to be fully beneficial.
Teaching Methods,Learning Environment,Sustainable Design
https://jesaun.journals.ekb.eg/article_115176.html
https://jesaun.journals.ekb.eg/article_115176_9f4eb4a6776646a3bd306d44f9a127a6.pdf
Assiut University, Faculty of Engineering
JES. Journal of Engineering Sciences
1687-0530
2356-8550
43
No 2
2015
03
01
TOWARDS A METHODOLOGY FOR INTEGRATING MODERN ARCHITECTURAL DOCUMENTATION TECHNIQUES
295
3190
EN
Kenzy
Mohammed
10.21608/jesaun.2015.115179
<span>The heritage buildings are considered an integral part of architecture in general, because of its important role in monitoring and documenting different historical stages affecting persons and reflecting on the architecture buildings to reinforce culture and concepts of the historical stage. This confirms the significant role played by accurate architectural documentation for the success of the various policies to maintain these valuable buildings, which can be maintenance, repair, improvement, rehabilitation or reconstruction, monitoring deterioration and expected risk rates. Heritage Conservation projects are divided into three main stages: “documentation, analysis and action. Therefore, the research study is concerned with documentation, monitoring and generating database stage, which results in the decision making in the next stage, where the success of those decisions depends on the efficiency of available information through comprehensive documentation. The study proposes a methodology for using the integration of modern architectural documentation techniques, which allows access to accurate and comprehensive information and data, by organizing the documentation project stages, and arrange the work out plans to clarify the accurate outputs which can be obtained in every stage, as well as expanding the use of documentation outputs and classifying the data to include a range of fields (heritage documentation - preservation and restoration - Disasters Coordination- scientific research and tourism), that are likely to benefit from such information, mostly if it is provided ,arranged and accessed from a single source, through classification and arrangement by field of use.</span>
https://jesaun.journals.ekb.eg/article_115179.html
https://jesaun.journals.ekb.eg/article_115179_fd37ebda5810d1f0169ae8ace65014c0.pdf