Tag Archives: electromagnetic fields

1737-1744 I. Vilcane, T. Koppel, J. Bartusauskis, V. Urbane, J. Ievins, H. Kalkis, and Z. Roja
Electromagnetic fields’ exposure to head, torso and limbs in office workplaces
Abstract |
Full text PDF (275 kB)

Electromagnetic fields’ exposure to head, torso and limbs in office workplaces

I. Vilcane¹*, T. Koppel², J. Bartusauskis¹, V. Urbane¹, J. Ievins¹, H. Kalkis³⁴, and Z. Roja⁴

¹Riga Technical University, Faculty of Engineering Economics and Management, institute of Occupational Safety and Civil Defence, Kalku str. 1, LV-1048 Riga, Latvia
²Tallinn University of Technology, Department of Business, Labour Environment and Safety, Ehitajate str. 5, EE19086 Tallinn, Estonia
³Riga Stradins University, Faculty of European Studies, Dzirciema str. 16, LV-1007 Riga, Latvia
⁴University of Latvia, Faculty of Chemistry, Ergonomic Research centre, Jelgavas str. 1, LV-1004 Riga, Latvia
*Correspondence: Inese.Vilcane@rtu.lv

Abstract:

The aim of this research was to investigate the electromagnetic fields in the modern office environment. Both low frequency and the high frequency electromagnetic fields were studied. The sources of elevated electromagnetic fields and the conditions under which they occur were identified. Measurements were performed by following a 14-point human body model, which characterizes the overall exposure of the sitting person.

The measurements analysis revealed the most typical sources of exposure to be loosely spread power wires and extension cables, but also power cables close to the worker’s body on the floor or beneath the table. Standard office devices were also rising the exposure levels when situated in close proximity to the worker.

Key words:

, , , ,




1053–1062 V. Mironovs, I. Boiko, T. Koppel and M. Lisicins
Cellular tubular structures from perforated metallic tape and its application
Abstract |

Cellular tubular structures from perforated metallic tape and its application

V. Mironovs¹, I. Boiko²*, T. Koppel³ and M. Lisicins¹

¹Riga Technical university, Faculty of Civil Engineering, Institute of Building Production, Azenes street 16/20–331, LV-1048 Riga, Latvia
²Riga Technical University, Faculty of Mechanical Engineering, Transport and Aeronautics, Institute of Mechanical Engineering, Ezermalas street 6k, LV-1006 Riga, Latvia
³Tallinn University of Technology, Department of Labor Environment and Safety, SOC351, Ehitajate tee 5, EE19086 Tallinn, Estonia
*Correspondence: irina.boiko@rtu.lv

Abstract:

 The objectives of performed research were the following: 1) check out the possibility of effective formation of the tubular and planar structures from the perforated steel tapes, which were obtained as a waste during stamping of fine-sized details, by cutting and bending; 2) testing of achieved tubular and annular structures for fixing up of the electrical cables and as electromagnetic shielding solutions; 3) analysis of achieved results and elaboration of the recommendations for using of lightweight tubular shields for the electrical cables. The actuality of research is connected with the re-using of metallic wastes and shielding solutions against electromagnetic fields. All objectives were reached successfully using bending for formation of the tubular structures. The bending strength of achieved structures and the shielding efficiency in a controlled environment was examined. The measurement results have shown that perforated steel will exhibit noticeable shielding properties against both the electric and magnetic field. Such results open up wide possible application of the planar and cellular tubular structures from perforated metallic tapes.

Key words:

, , ,




1015–1022 T. Koppel, A. Shiskin, I. Hussainova, H. Haldre and P. Tint
Electromagnetic shielding properties of ceramic spheres coated with paramagnetic metal
Abstract |
Full text PDF (601 kB)

Electromagnetic shielding properties of ceramic spheres coated with paramagnetic metal

T. Koppel¹*, A. Shiskin², I. Hussainova¹, H. Haldre³ and P. Tint¹

¹Tallinn University of Technology, Ehitajate 5, EE 12616 Tallinn, Estonia
²Faculty of Material Science and Applied Chemistry, Riga Technical University, 3 Paula Valdena str, LV-1048 Riga, Latvia
³Institute of Environmental Health and Safety, Jaam 14, EE 11615 Tallinn, Estonia
*Correspondence: tarmo.koppel@ttu.ee

Abstract:

 This study utilized a setup of radiofrequency generating and metering instruments to measure the reflective and pass-through properties of the innovative material of paramagnetic metal coated ceramic hollow spheres (MCS). The dimensions of the spherical articles reside around 50–250 μm, the thickness of metal (Cu) coating is 0.5–1.3 μm. The radiofrequency field was of 2.4 GigaHertz (GHz) frequency and radiated towards the material via a waveguide-horn antenna at 100 mWt power output. Two additional waveguide-horn antennas connected to a radiofrequency analyzer measured the reflection and pass-through characteristics of the material. Reflection and pass-through coefficients (from 0 to 1) were calculated to each tested sample. The material was tested at different thicknesses: from single – to multi (up to 5) mono-layers and 5 mm layer in bulk condition of MCS.
The measurement results show insignificant shielding characteristics for 1 to 5 layer thickness samples: pass-through coefficient from 0.96 to 0.92. Noteworthy shielding characteristics were starting to show in case of MCS mixed with graphite emulsion: transmission coefficient dropped to 0.16.
The latter sample demonstrates the prospective shielding characteristics of the material, since most of the radiofrequency radiation was not allowed to pass through the material neither to be reflected, but absorbed within the structure of the material.

Key words:

, , , ,




863-874 T. Koppel and P. Tint
Reducing exposure to extremely low frequency electromagnetic fields from portable computers
Abstract |
Full text PDF (421 kB)

Reducing exposure to extremely low frequency electromagnetic fields from portable computers

T. Koppel* and P. Tint

Tallinn University of technology, Ehitajate tee ⁵, EE¹⁹0⁸⁶ Tallinn, Estonia; *Correspondence: tarmo.koppel@ttu.ee

Abstract:

The relevance of this article can be described by the rapid development in computer technology which has resulted in widespread use of laptop computers. Consequently the population is now more exposed to the electromagnetic fields, emanating from such devices. The aim of this article is to test various intervention measures which would help to reduce the exposure. The authors focus only on the measures easily applicable by the general public. The effectiveness of the interventions is measured by reduced electric and magnetic field. This study focuses on the electromagnetic fields in the range of ⁵0 Hz to ⁴00 kHz. The importance of minimizing exposure to the electromagnetic fields is also stressed by the high level European bodies. Reduction of environmental risk factors, where possible, is in fact the corner stone of European occupational health legislation. The measurements are conducted using a novel ¹⁴-point model, covering the entire body of the user. Measurements from ⁴⁶ laptop computer workplaces provided data about ¹⁵⁶ unique exposure instances. The measurement results show that the least exposure scenario comprises of a laptop computer working on battery, having external input devices and display, the casing of the computer being properly grounded and power wires and adapters are positioned away from the user’s body.

Key words:

, , , ,




421-434 T. Koppel,, T. Tasa and P. Tint
Electromagnetic fields in contemporary office workplaces
Abstract |
Full text PDF (655 kB)

Electromagnetic fields in contemporary office workplaces

T. Koppel¹,*, T. Tasa² and P. Tint¹

¹Tallinn University of Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia;
*Correspondence: tarmo.koppel@ttu.ee
²Tallinn University Haapsalu College, Lihula mnt. 12, EE90507 Haapsalu,Estonia

Abstract:

Technological  progress  and  widespread  use  of  electronics  has  rapidly  increasedlevels of electromagnetic fields (EMFs) in workplaces during the last decade. Today’s workersare exposed to levels of EMFs unprecedented in history. This has caused concern amongst thegeneral  public.  Although  the  EMF  levels  of  such  modern  devices  fall  within  current  safetylimits, the recent studies have still raised questions regarding the biological effects well belowthe  safety  limits.  The  European  Union  and  the  World  Health  Organization  have  called  forscientists to conduct more studies in this field and to investigate all aspects of EMFs. The aimof  this  study  was  to  quantify  the  actual  levels  of  the  EMFs  in  contemporary  workplaces.  Asmost  of  studies  have  only  addressed  a  certain  frequency  range,  this  study  covers  all  thespectrum  of  low  (LF),  intermediate  (IF)  and  high  frequency  (HF)  EMFs.  Altogether  69workplaces were investigated. Great variations were detected across the workplaces, dependingmainly  on  the  computer  set-up  configuration.  Exposure  levels  proved  to  be  affected  by  thenearby electrical equipment, arrangement of wires or faulty appliances. At the end of the paperthe  authors  discuss  different  network  connection  technologies  and  provide  the  results  whichsuggest solutions  for lower HF EMF exposures that allow  for following of the precautionaryprinciple.Key words: electromagnetic fields, occupational exposure, office, reduction, mitigation.

Key words:

, , , ,