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Corona in Point – Plane Gaps as Influenced by a Surrounding Dielectric Enclosure

Research Abstract
The present paper is aimed at investigating experimentally the interaction between the processes taking place in the stressed gas volume of a positivety stressed point-to-plane gap and those occurring at the walls of a surrounding dielectric enclosure. The corona current-voltage characteristics and the corona current density distribution over the ground plane are investigated in the present paper with and without the presence of the dielectric enclosure. First of all, charging of the dielectric surfaces will be briefly reviewed. Secondly, the experimental setup is described. Finally, the obtained experimental results are discussed in the tight of gasdischarge physics.
Research Authors
M. Abdel-Salam, S. Abdel-Sattar, A. S. Abdallah, and A. Al-Shakiri
Research Department
Research Journal
The Middle East Power System Conference MEPCON 2005 , Dec. 7-9, 2005, Port said, Egypt
Research Member
Research Pages
NULL
Research Publisher
Middle East Power System Conference MEPCON
Research Rank
4
Research Vol
NULL
Research Website
NULL
Research Year
2005

On the Mitigation of Electromagnetic Pollution in Buildings

Research Abstract
The primary concern with any source of electricity is the fact that electromagnetic fields (EMF) are naturally emitted as a consequence of the transmission, distribution and use of electricity. While the electric fields are relatively easy to block, the magnetic fields are difficult to block and can cause some problems including human biological effect. Since electromagnetic field is present wherever electricity is used, there is a level of EMF in any building due to multiple sources of electromagnetic fields. These sources include the structure's electrical distribution systems, lights, transformers, electric fans, copiers, underground wires, ground-mounted transformers, common sources within the home etc. Also the nearby high voltage power lines are considered one of the EMF sources. This makes the ambient level of indoor electromagnetic pollution exceeds the tolerable limits. To reduce indoor electromagnetic pollution, different electromagnetic fields mitigation methods could be used. Different mitigation methods are summarized in this paper. The cancellation method by using the correct indoor electrical wiring is discussed in this paper. The use of metal tubes as well as conduits for wires is considered, in this paper, as a way of electromagnetic fields mitigation. The effect of material shielding on the indoor electromagnetic pollution is discussed also in this paper.
Research Authors
S. Abdel-Sattar,
Research Department
Research Journal
International Conference for Development and the Environment in the Arab World, Assiut University, Assiut, Egypt, March 21-23, 2006
Research Member
Research Pages
NULL
Research Publisher
Assiut University, Assiut, Egypt
Research Rank
4
Research Vol
NULL
Research Website
NULL
Research Year
2006

review of modern references to resolve the issue of electrical energy use impact on electromagnetic pollution around us

Research Abstract
Electric power is the most common source of power all over the world because it is easily to be generated and transmitted to where it is used. As electricity moves through wires, technical instruments, appliances and equipment, it produces two types of fields, an electric (EFs) and magnetic (MFs) fields, which together are called an electromagnetic fields (EMFs). The EFs result from the strength of the voltage and it is easy to be shielded while the MFs are proportional to the current and it is difficult to be shielded. It is impossible to generate, transmit, distribute and use electrical energy without creating EMFs1. The power networks of any country consist of electrical generation, transmission and distribution facilities. Once electricity is delivered to the user, it continues to produce EMF throughout the wiring systems of offices, homes, schools, factories and other structures depending on the load. The appliances and electrical equipment - connected to these wiring systems - produce also their own EMFs1-2. In workplaces, the sources of EMFs include computers, laboratory devices, cell phones, fax machines, copy machines, fluorescent lights, printers, scanners, telephone switching systems, electrical instruments, motors and other electrical devices. In homes, sources of EMF include electric blankets, electric water heaters, hairdryers, electric shavers, television sets, stereo systems, air conditioners, fluorescent lights, electric can openers, telephone answering machines, cell and portable phones, refrigerators, blenders, portable heaters, clothes washers and dryers, coffee makers, vacuum cleaners, toasters, and microwave ovens1-2. The EMF sources are rapidly growing - as technology grows - that make the problem of EMF pollution be more complicated and more dangerous. This environmental terrorism around us is very difficult for one to be aware of its presence because one can not see it, can not smell it, can not taste it, or can not touch it. Considering that, it is important to understand what causes EMF pollution and what to look for in our everyday tour. Current literatures evidence directly associates EMF – due to the use of electricity - with a lot of diseases starting with headache and ending by cancers. The review of different research results shows that the EMFs exposure should be considered as a possible human carcinogen. On the other hand, some researchers - based on a consistency in epidemiological studies – associate between residence near power lines and the higher risk of leukaemia in children. This means that although the exposure to EMFs may cause cancer but it can not be excluded that it cause cancers1-23. In conclusion, the electromagnetic fields around us that radiated from different sources have environmental effects and hazards of various dangers on human beings, animals and plants1-23, therefore, it is important to assess the values of the electric and magnetic fields in our environments and check against the permissible safety standards limits. The degree of electromagnetic pollution is required to be defined and then the category of the air quality in our environments will be specified. Literatures3-16 shows also that childhood cancer might be associated with exposures to residential and occupational power-frequency – extremely low frequency – fields(ELFs). Numerous studies in many countries have been undertaken of possible increased cancer risks in children and adults from EMF exposures. Special attention has focused on leukemia and on brain tumours, which early reports had suggested might be increased. It has been concluded that ELFs are possibly carcinogenic to humans, based on consistent statistical associations of high level residential magnetic fields with a doubling of risk of childhood leukemia. Some epidemiological studies1-23 has suggested that a link may exist between exposure to power-frequency EMFs and certain types of cancer. Other studies have found no such link. Laboratory researchers are studying how such an association is biologically possible. Several studies17-20 have reported increased cancer risks for jobs involving work around electrical equipment. At this point, there is no scientific consensus about EMFs issue except a general agreement that better information, more data and more studies are needed. More effort, data and studies are also required to resolve the issue of the power-frequency EMF levels of exposure which are safe or unsafe. The public concern is sustained by uneven reporting on this issue by the mass media, by the inability of scientists to guarantee that no risk exists, and by statements from scientists and government officials that more research is needed. The scope of this paper is limited to review the modern references of the significant developments in the electromagnetic pollution due to the use of electricity. This paper also covers modern references available in journals, proceedings and reports. The authors have tried to select publications which - in their viewpoint - make a useful contribution to resolve the issue of electromagnetic energy use impact on electromagnetic pollution around us and its effects on public health.
Research Authors
S.Abdel-Sattar and Kamel A. Shoush
Research Department
Research Journal
Al-Azhar Engineering tenth International Conference, 24-26 Dec. 2008, Al-Azhar University, Egypt
Research Member
Research Pages
NULL
Research Publisher
Al-Azhar University, Egypt
Research Rank
3
Research Vol
NULL
Research Website
NULL
Research Year
2008

Effect of magnetic field on the friction and wear caused by the scratch of high density polyethylene

Research Abstract
The present work discusses the friction and wear of polyethylene as bearing materials scratched by steel insert in the presence of magnetic field. Tests were carried out at dry and oil lubricated surfaces. Paraffin, fenugreek, camphor, cress and Habet El-Baraka oils were used as lubricants. The friction coefficient and wear of the tested composites were investigated using a tribometer designed and manufactured for that purpose. It was found that, at dry sliding, friction coefficient displayed the highest values, where a value of 1.5 was approached. Application of magnetic field on the sliding surface caused significant friction decrease. As the intensity of the magnetic field increases, friction coefficient decreased. Wear of polyethylene increased with increasing applied load, and significantly increased under the application of the magnetic field. Lubricating the sliding surface by paraffin oil significantly decreased friction coefficient, while magnetic field significantly decreased friction and increased wear. Friction coefficient displayed by fenugreek oil represented relatively higher values indicating the weak lubricating properties of that oil. As the magnetic field was applied, friction coefficient decreased. Wear in the presence of magnetic field significantly decreased. Camphor oil displayed relatively lower friction and wear values than that observed for fenugreek oil. Application of magnetic field on the sliding surface caused significant friction and wear reduction. Besides, friction coefficient and wear displayed by cress oil decreased as a result of the magnetic field. Finally, Habit El-Baraka oil displayed the lowest values of friction coefficient among the tested oils. The wear resistance observed was quite good.
Research Authors
S.Abdel-Sattar et. al.
Research Department
Research Journal
7th International Engineering Conference, 23-28 March 2010, Mansoura University, Egypt
Research Member
Research Pages
NULL
Research Publisher
Mansoura University, Egypt
Research Rank
3
Research Vol
NULL
Research Website
NULL
Research Year
2010

Effect of Magnetic Field on Friction Coefficient Displayed by Rolling Bearings

Research Abstract
The effect of magnetic field and electric current on the friction coefficient displayed by rolling bearing greased by lithium grease dispersed by solid lubricants such as graphite, molybdenum disulphide, talc and polymeric particles is investigated. It was shown that the magnetic field had no effect on friction coefficient observed for lithium grease without additives. Addition of talc showed significant increase in friction coefficient. This increase was influenced by magnetic field. No significant effect on friction coefficient was observed for grease dispersed by molybdenum disulphide. Generally molybdenum disulphide displayed relatively lower friction coefficient than graphite and talc. Copper particles dispersed in grease displayed the lowest friction values. Friction coefficient displayed by grease significantly decreased with increasing electric voltage due to decrease of grease viscosity as the voltage increased. In the presence of graphite and talc, friction coefficient increased up to maximum then decreased with increasing voltage. Slight friction increase was observed for grease dispersed by copper. The lowest friction coefficient was displayed by molybdenum disulphide dispersing grease. The highest friction coefficient was displayed by grease dispersed by graphite and talc, while the lowest friction was shown for molybdenum disulphide dispersing grease. Grease dispersed by high density polyethylene showed friction decrease. The lowest friction reduction was observed for polymethyl methacrylate. The strong adhesion of polytetrafluroethylene particles into the sliding surfaces significantly increased friction coefficient. It seems that polytetrafluroethylene particles were adhered to surfaces of inner and outer races as well as the balls. Changing the terminal of the voltage applied to the rotating shaft cased significant friction decrease for polymethyl methacrylate. Viscosity of the grease decreased with increasing the voltage. Friction coefficient decreased for high density polyethylene and polytetrafluroethylene. The lowest friction values were observed at 6 volts which indicated that increasing voltage across the sliding surface could significantly decrease friction coefficient.
Research Authors
Abdel-Sattar S., Alahmady A. and Ali W. Y.
Research Department
Research Journal
Journal of the Egyptian Society of Tribology (EGTRIB Journal)
Research Member
Research Pages
27-39
Research Publisher
Journal of the Egyptian Society of Tribology (EGTRIB Journal)
Research Rank
2
Research Vol
8-3
Research Website
NULL
Research Year
2011

Influence of Magnetic Field on the Sliding of Steel Against Lubricated Polyamide

Research Abstract
The present work investigates the influence of magnetic field on the friction coefficient displayed by sliding of steel pin on polyamide disc lubricated by paraffin oil and dispersed by different lubricant additives such as zinc dialkyldithiophosphates (ZDDP), molybdenum disulphide (MoS2), heteropolar organic based additive (CMOC), graphite (C), detergent additive (calcium sulphonate) (DA), polytetrafluroethylene (PTFE) and polymethyl methacrylate (PMMA). Based on the experiments carried out in the present work, it was found that, at surfaces lubricated by paraffinic molecules friction coefficient decreased with increasing applied load. As the magnetic field increased friction coefficient increased. When the oil was dispersed by ZDDP additive significant decrease of friction was observed. The performance of ZDDP additive was not affected by application of the magnetic field. Dispersing Mo S2 or C in the lubricating oil caused significant friction increase. The effect of magnetic field on performance of MoS2 was insignificant, while magnetic field caused slight friction reduction in the presence of C. Magnetic field decreased friction coefficient when the oil was dispersed by CMOC. Under the action of magnetic field the force of adhesion significantly increased causing proper surface coating which caused the friction decrease. Oil dispersed by calcium sulphonate showed significant friction decrease due to the polarity of its molecules. Application of magnetic field caused further friction decrease. As a result of the quite good response of DA additive with magnetic field based on the values of friction coefficient observed for the oil dispersed by DA additive, it can be recommended to use this additive when magnetic field is applied. The good lubricating properties observed for PTFE additive can be from its ability to form a layer on the sliding surfaces. PTFE particles dispersed in the oil were much influenced by magnetic field, where the lowest value was displayed at the highest intensity of magnetic field. The same trend of friction decrease was observed for PMMA particles dispersed in oil.
Research Authors
Zaini H., Alahmady A., Abdel-Sattar S., and Ali W. Y.
Research Department
Research Journal
Journal of the Egyptian Society of Tribology (EGTRIB Journal)
Research Member
Research Pages
39-51
Research Publisher
Journal of the Egyptian Society of Tribology (EGTRIB Journal)
Research Rank
2
Research Vol
9-1
Research Website
NULL
Research Year
2012

Fixed-structure LPV-IO controllers: An implicit representation based approach

Research Abstract
NULL
Research Authors
Wollnack, Simon; Abbas, Hossam Seddik; Tóth, Roland; Werner, Herbert
Research Department
Research Journal
Automatica
Research Pages
p 282-289
Research Publisher
NULL
Research Rank
1
Research Vol
v 83
Research Website
NULL
Research Year
2017

A novel SMA-based micro tactile display device for elasticity range of human soft tissues: Design and simulation

Research Abstract
NULL
Research Authors
Mansour, Nader A.; Fath El-Bab, Ahmed M.R.; Assal, Samy F.M.
Research Journal
IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM
Research Pages
p 447-452
Research Publisher
NULL
Research Rank
3
Research Vol
NULL
Research Website
NULL
Research Year
2015

Design of a compact dual-band folded-waveguide bandpass filter using multilayer waveguide resonators

Research Abstract
NULL
Research Authors
International Journal of RF and Microwave Computer-Aided Engineering
Research Department
Research Journal
International Journal of RF and Microwave Computer-Aided Engineering
Research Member
Research Pages
p 780-788
Research Publisher
NULL
Research Rank
1
Research Vol
v 25, n 9
Research Website
NULL
Research Year
2015

Modeling and experimental testing of three-tip configuration tactile sensor for compensating the error due to soft tissue surface irregularities during stiffness detection

Research Abstract
NULL
Research Authors
Fouly, Ahmed; FathEl-Bab, Ahmed M.R.; Nasr, Mohamed N.A.; Abouelsoud, A.A.
Research Journal
Measurement: Journal of the International Measurement Confederation
Research Pages
p 112-122
Research Publisher
NULL
Research Rank
1
Research Vol
v 98
Research Website
NULL
Research Year
2017
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