Personal computers, apart from being ubiquitous in our everyday activity, very often have been object of study for eventual negative health consequences. During the recent years, a great number of schools in Albania a...Personal computers, apart from being ubiquitous in our everyday activity, very often have been object of study for eventual negative health consequences. During the recent years, a great number of schools in Albania are equipped with lab rooms for teaching computer skills. This has motivated us to carry out a campaign of measuring the intensity of electric and magnetic fields is such places in the schools of Gjirokastra. This paper presents the results of such a study for the evaluation of the possible hazard related to the exposure to this “electro-smog” of the students and teachers. This is done by comparing the measured values of physical quantities with the respective limits and standards recom-mended by scientists and established by European directives such as 2004/40/CE and 1999/519/CE.展开更多
As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and pr...As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.展开更多
The geology and hydro-geophysical features can aid in identifying borehole location.The study aims to investigate groundwater aquifers and best location of boreholes in the crystalline basement area of Abu Zabad near ...The geology and hydro-geophysical features can aid in identifying borehole location.The study aims to investigate groundwater aquifers and best location of boreholes in the crystalline basement area of Abu Zabad near El Obeid Southwest,Sudan.The study area is underlain by two aquifers formations from Precambrian age.The oldest units of basement complex of area under investigation consist of metamorphic rocks including gneiss,schist,and quartzite.The geophysical methods electromagnetic(EM)and vertical electrical sounding(VES)surveys showed that best aquifers yield for construction of boreholes are in weathering and fractures formation.The EM results revealed that structural features are significant for groundwater potential and interpretation of the VES data also revealed four geo-electric layers,but generally two distinct lithologic layers,which include Superficial deposit and bedrock-basement respectively.The curves generated from the data revealed H curve and HK curve,and thickness of these layers varies from 15 m to 50 m in the area.The aquifer thickness range from 20 m to 30 m.The study concludes that these techniques are suitable for identifying borehole location in the basement rock in Abu Zabad Area Sudan.展开更多
Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. ...Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. A test rig was built to study the susceptibility of VDUs to magnetic fields at fundamental and third harmonic frequencies. It was found that the susceptibility level is largely dependent on refresh rate of the VDU and the orientation of the external ELF field. It was also found that the VDU susceptibility is significantly increased in the presence of harmonic frequency magnetic fields. About 30% of the tested samples have susceptibility levels higher than that stated in IEC 1000-4-8 standard.展开更多
According to many scientists, there are some redundancies in the SI system of units. Through an entropy approach that depends on a previous analogy between the electrical, mechanical and thermal fields;it was possible...According to many scientists, there are some redundancies in the SI system of units. Through an entropy approach that depends on a previous analogy between the electrical, mechanical and thermal fields;it was possible to introduce a system of units that removes such redundancies. According to the second law of thermodynamics, the temperature was defined as a quality of heat. Following a proved analogy, the electrical and magnetic potentials may represent also the qualities of electric and magnetic fluxes. According to published experimental results, the electric and the magnetic potentials generates also electromotive forces, EMF, that were measured by Al-Fe thermocouples. The chemical potential or the concentration gradient generates also an EMF, as in the concentration cells, which is measured here by the same Al-Fe thermocouple. Such measurement-results are introduced to define a unique scale for measuring the potentials or qualities of the thermal, chemical, electric, and magnetic fields. The mentioned qualities are not defined by directly measurable quantities, as length and time, but they are found as functions of dimensionless concentrations of mass or energy fluxes. Hence, the volt, as a unit of the introduced EMF scale for potentials measurement, is postulated as a dimensionless unit. Finally, a universal system of units that is based only on three dimensions;L, T, and E, and four fundamental units;meter, second, Joule and volt is introduced in this paper to delete the SI redundancies. The energy replaces the mass as a fundamental unit in the introduced US as it plays a dominant role in most of the scientific and engineering fields. The ampere is not included as a fundamental unit since the charge is considered as a form of energy that is measured in one of the US fundamental units, Joule. The candela and the mole were also not considered as fundamental units as they can be related to the selected fundamental units by appropriate numbers. The limited number of dimensions in the introduced US simplifies the application of the “π” dimensional theorem to find plausible relations between the main parameters that characterize many physical phenomena and the energy conversions and interactions.展开更多
文摘Personal computers, apart from being ubiquitous in our everyday activity, very often have been object of study for eventual negative health consequences. During the recent years, a great number of schools in Albania are equipped with lab rooms for teaching computer skills. This has motivated us to carry out a campaign of measuring the intensity of electric and magnetic fields is such places in the schools of Gjirokastra. This paper presents the results of such a study for the evaluation of the possible hazard related to the exposure to this “electro-smog” of the students and teachers. This is done by comparing the measured values of physical quantities with the respective limits and standards recom-mended by scientists and established by European directives such as 2004/40/CE and 1999/519/CE.
文摘As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.
文摘The geology and hydro-geophysical features can aid in identifying borehole location.The study aims to investigate groundwater aquifers and best location of boreholes in the crystalline basement area of Abu Zabad near El Obeid Southwest,Sudan.The study area is underlain by two aquifers formations from Precambrian age.The oldest units of basement complex of area under investigation consist of metamorphic rocks including gneiss,schist,and quartzite.The geophysical methods electromagnetic(EM)and vertical electrical sounding(VES)surveys showed that best aquifers yield for construction of boreholes are in weathering and fractures formation.The EM results revealed that structural features are significant for groundwater potential and interpretation of the VES data also revealed four geo-electric layers,but generally two distinct lithologic layers,which include Superficial deposit and bedrock-basement respectively.The curves generated from the data revealed H curve and HK curve,and thickness of these layers varies from 15 m to 50 m in the area.The aquifer thickness range from 20 m to 30 m.The study concludes that these techniques are suitable for identifying borehole location in the basement rock in Abu Zabad Area Sudan.
文摘Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. A test rig was built to study the susceptibility of VDUs to magnetic fields at fundamental and third harmonic frequencies. It was found that the susceptibility level is largely dependent on refresh rate of the VDU and the orientation of the external ELF field. It was also found that the VDU susceptibility is significantly increased in the presence of harmonic frequency magnetic fields. About 30% of the tested samples have susceptibility levels higher than that stated in IEC 1000-4-8 standard.
文摘According to many scientists, there are some redundancies in the SI system of units. Through an entropy approach that depends on a previous analogy between the electrical, mechanical and thermal fields;it was possible to introduce a system of units that removes such redundancies. According to the second law of thermodynamics, the temperature was defined as a quality of heat. Following a proved analogy, the electrical and magnetic potentials may represent also the qualities of electric and magnetic fluxes. According to published experimental results, the electric and the magnetic potentials generates also electromotive forces, EMF, that were measured by Al-Fe thermocouples. The chemical potential or the concentration gradient generates also an EMF, as in the concentration cells, which is measured here by the same Al-Fe thermocouple. Such measurement-results are introduced to define a unique scale for measuring the potentials or qualities of the thermal, chemical, electric, and magnetic fields. The mentioned qualities are not defined by directly measurable quantities, as length and time, but they are found as functions of dimensionless concentrations of mass or energy fluxes. Hence, the volt, as a unit of the introduced EMF scale for potentials measurement, is postulated as a dimensionless unit. Finally, a universal system of units that is based only on three dimensions;L, T, and E, and four fundamental units;meter, second, Joule and volt is introduced in this paper to delete the SI redundancies. The energy replaces the mass as a fundamental unit in the introduced US as it plays a dominant role in most of the scientific and engineering fields. The ampere is not included as a fundamental unit since the charge is considered as a form of energy that is measured in one of the US fundamental units, Joule. The candela and the mole were also not considered as fundamental units as they can be related to the selected fundamental units by appropriate numbers. The limited number of dimensions in the introduced US simplifies the application of the “π” dimensional theorem to find plausible relations between the main parameters that characterize many physical phenomena and the energy conversions and interactions.
