Volume 13 (2015)
  Number 3

Journal full text: Vol 13 No 3

Contents


Pages

629-638 R. Chotěborský and M. Linda
FEM based numerical simulation for heat treatment of the agricultural tools
Abstract |
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FEM based numerical simulation for heat treatment of the agricultural tools

R. Chotěborský¹ and M. Linda²⋅*

¹Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Kamýcka 129, CZ-16521 Praha – Suchdol, Czech Republic 2Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Electrical Engineering and Automation, Kamýcka 129, CZ-16521 Praha – Suchdol, Czech Republic; *Correspondence: linda@tf.czu.cz

Abstract:

Quenching as a heat treatment method is commonly used to control the mechanical properties of steels. This article deals with the modelling and simulation of quenching of steel chisel using a multi–phase model. The process of the heat treatment is non stationary phase due to temperature variation with time. In this study, the problem of heat transfer in three dimensional phase was transformed into a two dimensional axisymmetric case. ElmerFem solver was used for the heat transfer through different cooling media such as water, oil and salt bath. The results from heat solver were used for austenite transformation modelling by applying Johnson–Mehl–Avrami–Kolmogorov equation in TTT diagram. The Scheill’s decomposition was used for anisothermal transformation of austenite. The hardness prediction was done according to simple mixture rule where total hardness of the steel was calculated based on volume of the phases and their Vickers hardness.

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639-653 H. Kallakas, M.A. Shamim, T. Olutubo, T. Poltimäe, T.M. Süld, A. Krumme and J. Kers
Effect of chemical modification of wood flour on the mechanical properties of wood-plastic composites
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Effect of chemical modification of wood flour on the mechanical properties of wood-plastic composites

H. Kallakas*, M.A. Shamim, T. Olutubo, T. Poltimäe, T.M. Süld, A. Krumme and J. Kers

Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia;
*Correspondence: heikko.kallakas@ttu.ee

Abstract:

The poor compatibility between the highly hydrophilic wood fibres and the hydrophobic polymers is associated with a loss of mechanical properties. Therefore, to improve the interfacial adhesion between the polymer matrix and wood flour (WF), a chemical modification of WF is an appropriate solution. This study analyzes the influence of different chemical modifications of WF on the mechanical properties of wood-plastic composites (WPCs). WPC test samples were prepared from birch (Betula) WF with a mesh size of 0.⁶³ mm as the filler material and polypropylene (PP) as the matrix material. WF was chemically modified by six different methods to increase its adhesion to, and compatibility with, the polymer matrix. The six chemical methods used were: alkaline (NaOH) modification, polyvinyl alcohol (PVA) modification, silane treatment with ³-aminopropyltriethoxysilane (APTES), acetylation with acetic anhydride, cyanoethylation, and wood fibre esterification. The composites were produced using a twin-screw extruder and the test samples were prepared by injection moulding. The composites’ mechanical properties (three-point bending test), Charpy impact strength and thermal properties were tested. In addition, SEM micrographs of WPC surfaces were generated. WF as a filler material enhanced the flexural properties, while impact strength decreased, making the material more rigid and brittle. The test results revealed that the chemical modifications of WF improved the mechanical properties and crystallinity of WPC materials, while the melting temperature decreased. However, the influence of the chemical modification on the mechanical and thermal properties of WPC varied by method.

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654-661 A. Krofová and M. Müller
Influence of dusty micro-particles contamination on adhesive bond strength
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Influence of dusty micro-particles contamination on adhesive bond strength

A. Krofová* and M. Müller

Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Science, Kamýcká 129, CZ-16521 Prague, Czech Republic; *Correspondence: krofovaa@tf.czu.cz

Abstract:

A necessity for a bond creation is one of common attributes of production companies. An adhesive bonding technology is a method of a connecting. This method is suitable for workings with a single and serial production. Many research projects dealt with a preparation of adhesive bonds, degradation aspects etc. An area, which has not been properly investigated at present, is an influence of a contamination of the adhesive bonds by dusty micro-particles, e. g. from a ventilation of assembly shops, production hall etc. The research was focused on the evaluation of the influence of dusty micro-particles contamination of the two-component epoxy adhesive at the hardening process. The dusty micro-particles were gained from the filtering equipment used in a production hall. Sizes of gained dusty particles were analysed on sieves of dimensions 315 μm, 250 μm, 160 μm, 90 μm. Subsequently, these particles were added in various ratios into the mixture of the adhesive during its preparation. The adhesive bonds containing the dusty particles of the sizes 250 µm, 160 µm and 90 µm showed the fall of the adhesive bond strength. The adhesive bonds containing the dusty particles of the size 315 µm showed the mild increase of the adhesive bond strength. The failure area did not change owing to the contamination of the adhesive bond with the dusty particles.

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662-670 M. Lisicins, V. Mironovs, I. Boiko and V. Lapkovskis
Sandwich wall constructions made of perforated metallic materials
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Sandwich wall constructions made of perforated metallic materials

M. Lisicins¹*, V. Mironovs¹, I. Boiko² and V. Lapkovskis¹

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 Transport and Mechanical Engineering, Institute of Mechanical Engineering, Ezermalas street 6k, LV-1006 Riga, Latvia
*Correspondence: mihails.lisicins@rtu.lv

Abstract:

The formation of cellular core for sandwich wall constructions made of perforated steel band is presented in the paper. The information about the main mechanical properties of perforated tapes and plates is provided. Basic technological methods for obtaining cellular structures from perforated metallic tape achieved from waste material by stamping are suggested. The main attention is focused on the analysis of the compressive strength of key elements of obtained cellular structures. Examples of the use of cellular structures made of perforated metallic materials in sandwich wall constructions are given. The main benefits of perforated metallic materials usage in sandwich wall’s construction are outlined.

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671-679 V. Maksarov
Improving the accuracy of manufacturing of hydraulic power cylinders using vibration-proof cutting tool
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Improving the accuracy of manufacturing of hydraulic power cylinders using vibration-proof cutting tool

V. Maksarov

National Mineral Resource University, department of mechanical engineering, Vasilevsky island, 21 Line, House 2, 199106 St. Petersburg, Russia; e-mail: maks78.54@mail.ru

Abstract:

The article introduces new results on designing multilayer cutting tool holder. Experimental study of metal turning process workpieces shows efficient dynamic damping of oscillations. The coefficient of oscillations absorption and damping is increased due to large dissipative force of the material holder oriented in different deformation directions of holder material. Key words: flat rolled stock, heterogeneity of structures, oriented deformation, adjustable anisotropy, multi-layered damping tool holder.

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680-689 Č. Mizera, D. Herák, M. Müller and P. Hrabě
Mechanical behaviour of polymeric composite with fibres of false banana (Ensete ventricosum)
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Mechanical behaviour of polymeric composite with fibres of false banana (Ensete ventricosum)

Č. Mizera¹*, D. Herák², M. Müller³ and P. Hrabě⁴

¹ ²Czech University of Life Science Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ-16521 Praha 6 Suchdol, Czech Republic
³ ⁴Czech University of Life Science Prague, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Kamýcká 129, CZ-16521 Praha 6 Suchdol, Czech Republic *Correspondence: mizera@tf.czu.cz

Abstract:

This study was focused on the analysis of the deformation characteristics of the polymer composite with continuous phase in the form of two-part epoxies and discontinuous phase (reinforcing particles) in the form of fibres of false banana (Ensete ventricosum). The aim of the experiment was to describe the mechanical behaviour of polymeric composite reinforced by fibres of false banana under tensile loading and to determine the modulus of elasticity and deformation energy. The fibres of Ensete ventricosum, originally from Ethiopian region Hawasa, were used in this experiment. Reinforcing fibres were prepared in sizes of lengths 1–2, 2–3, 3–5, 5–6, 7–8, 9–10, 15, 20, 25, 30, and 35 mm with randomly fibres arrangement in matrix. The fibres with length of 1–2, 2–3, 3–5, 5–6, 7–8 and 9–10 mm were used in short fibres composites and fibres with length of 10, 15, 20, 25, 30 and 35 mm in long fibres composites. The composite material was created with 2 wt.% of the filler. The modulus of elasticity of the short-fibre composite material was increased of 28 ± 12% by adding Enset fibres as the filler. The modulus of elasticity of the long-fibre composite material was increased of 46 ± 14%. The influence of the fibre length on the value of the volume deformation energy was not proved.

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690-699 I. Muizniece, L. Vilcane and D. Blumberga
Laboratory research of granulated heat insulation material from coniferous forestry residue
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Laboratory research of granulated heat insulation material from coniferous forestry residue

I. Muizniece*, L. Vilcane and D. Blumberga

Riga Technical University, Institute of Energy Systems and Environment, Azenes Street ²¹-¹, LV-¹0⁴⁸ Riga, Latvia;
*Correspondence: indra.muizniece@rtu.lv

Abstract:

The purpose of this research paper is to determine the heat conductivity of a granular heat insulation material made of coniferous greenery (fine twigs and needles), and the suitability of the material for application as heat insulation. In order to achieve the objective, a three-factor experiment plan was developed, and 11 samples produced. The thermal conductivity coefficient, moisture content, and density of the samples was determined. A full analysis of the experiment plan was compiled on the basis of the obtained results. The analysis results suggest that size composition, density, and tree species affect the thermal conductivity of the material. It was discovered that smaller spruce greenery insulation material pellets have a smaller thermal conductivity coefficient, which indicates a better capacity for retaining heat.

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700-708 M. Müller
Hybrid composite materials on basis of reactoplastic matrix reinforced with textile fibres from process of tyres recyclation
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Hybrid composite materials on basis of reactoplastic matrix reinforced with textile fibres from process of tyres recyclation

M. Müller

Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Science, Kamýcká 129, 165 21 Prague, Czech Republik; e-mail: muller@tf.czu.cz

Abstract:

The paper deals with a testing of composite materials reinforced with fabric, which were obtained after a recycling process of used tyres and a matrix is on a base of reactoplastics. The aim of the research was to set a possible utilization of unsorted textile waste from the process of the tyres recycling in the area of the polymeric composite systems. The subject of performed experiments was the hybrid polymeric composite, whose continuous phase was in a form of a two-component epoxy adhesive and a discontinuous phase (reinforcing particles) in a form of Polyamide PA (fibres) and rubber particles (granules of different sizes). An influence of a tensile stress, an elongation and an impact strength on the newly suggested hybrid composite materials were experimentally tested. Key words: hybrid polymeric composite, mechanical properties, morphology of fibres, tyre recycling.

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709-722 V.V. Pelenko, E.I. Verboloz and A.V. Baranenko
The theoretical analysis and optimization of the cutting knife- grille pair parameters in the screws
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The theoretical analysis and optimization of the cutting knife- grille pair parameters in the screws

V.V. Pelenko, E.I. Verboloz* and A.V. Baranenko

St. Petersburg National Research University of Information Technologies, Mechanics and Optics, Institute of Refrigeration and Biotechnology, Department of Food Engineering and Automation, 9 Lomonosov St., 191002 St. Petersburg, ITMO University Russia; *Correspondence: elenaverboloz@mail.ru

Abstract:

We show how energy-force knife-grille pair parameters depend on their tightening torque which also indicate the node which is the most dynamically and thermally tensed. The research demonstrates that the temperature, at the junction of the knife-grille, varies in the 10°C, and therefore this is a significant factor in the rate increasing of the grids and knives deterioration. From the condition of the screw grille and the knife blade compatibility deformations, we are shown the analytical dependence between the structural and technological characteristics, which allows us to minimize the depreciation value of the grille and the knife, as well as to reduce the energy intensity of the grinding process. Key words: lattice, the cutter knife, friction, bending, wear, temperature, pressure, distortion, efficiency, performance, etc.

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723-731 P. Valášek
Polymeric microparticles composites with waste EPDM rubber powder
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Polymeric microparticles composites with waste EPDM rubber powder

P. Valášek

Czech University of Life Sciences Prague, Department of material science and manufacturing engineering, Kamýcká 129, CZ-16521, Prague, Czech Republic; e-mail: valasekp@tf.czu.cz

Abstract:

Polymeric materials filled with inorganic microparticles can be described as polymeric microparticle composites. These materials combine the various mechanical, physical and chemical properties of different phases. Waste microparticles can also be used as filler. Inclusion of these waste microparticles can optimize the required mechanical properties and decrease the price. This paper describes the possibilities of using recycled waste rubber powder in polymer composite systems. The aim of the experiment was to quantify the mechanical properties of epoxy resin (Glue Epox Rapid – with increased speed of hardening) and polyurethane (Sika Power – resin based on polyol) filled with recycled EPDM rubber powder (29 µm) gained from a Czech company and to describe the changes in the mechanical qualities with a changeable amount of microparticles. Composites were prepared with a different filler concentration of resins (5–35 volume percent). Cohesive and adhesive characteristics were chosen for the quantification of the system. Adhesive strength to the steel adherent was tested by means of lap-shear tensile strength. Cohesive strength was tested by means of tensile strength. Hardness was measured by the Shore D method. The described use of waste material is inexpensive and offers the possibility of recycling material. The application of waste EPDM powder in the area of resins is a benfitial way of material usage which should be preferred.

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732-738 J. Volf, J. Svatos, P. Koder, V. Novak, S. Papezova, V. Ryzhenko andJ. Hurtecak
Pressure distribution measurement system PLANTOGRAF V12 and its electrodes configuration
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Pressure distribution measurement system PLANTOGRAF V12 and its electrodes configuration

J. Volf*, J. Svatos, P. Koder, V. Novak, S. Papezova, V. Ryzhenko andJ. Hurtecak

Czech University of Life Sciences Prague, Faculty of Engineering, Kamycka 129, CZ-16521 Prague, Czech Republic; *Correspondence: volf@tf.czu.cz Abstract: This paper describes Plantograf V12, which is used for the investigation of the pressure distribution between an object, e.g. a foot sole or a tire tread pattern, and the transducer. It can be used for analysing steps, assessing the great joints and improving stability, as well as in the fields of sport medicine and car industry. The system processes variable time pressure signals in real time. The instrument has 16,400 sensors (with a diameter of 2.5 mm each in a matrix arrangement of 128 x 128) concentrated in the active area as large as 500 x 500 mm; it is able to sample and process up to 1,000 frames per second. A full frame is created by all 16,400 sensors. The pressure distribution frame is represented in 256 colour levels in a 2D or 3D model view and it is possible to post-process the measured data on a PC. The design of the electrodes, the properties of the transducers, the operating software and the pressure distribution measurements in biomechanics are presented in this article. Key words: Plantograf, conductive elastomer, electrodes, pressure distribution, tactile transducer.INTRODUCTION

Abstract:

Plantograf V12 is a tactile transducer that is able to pick up tactile information froma particular object and convert this information into an electrical signal. This sensor is used in the following applications: measurement of static and dynamic pressure distribution, human steps analysis, sitting position analysis, pressure distribution, the analysis of a flat human foot, and the analysis of the status of great joints (Volf et al., 1997; Volf et al., 2001). Plantograf V12 should fulfil the following conditions: the sensor should not affect the measured pressure distribution results, it should measure both static and dynamic load, and it should have sufficient sensitivity and accuracy in each point of the sensor matrix for the given application. These parameters are specified in a table of technical parameters of the Plantograf. This paper focuses on the description of the Plantograf V12 matrix design, the optimal electrode size determination, and the properties of the operating software.

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741-749 R. Arvola and Ü. Kristjuhan
Workload and health of older academic personnel using telework
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Workload and health of older academic personnel using telework

R. Arvola* and Ü. Kristjuhan

Tallinn University of Technology, Tallinn School of Economics and Business Administration, Tallinn, Estonia;
*Correspondence: rene.arvola@ttu.ee

Abstract:

Aim of the study was to measure telework usage and to explore interactions between health, workload and telework. Telework is work that is carried out outside the central office, involving new technology that permits communication. Work carried out at any time, at any place, has been very common in the case of research institutes and universities. This type of work has advantages and disadvantages for both an employee and employer. The study of telework was carried out in Tallinn University of Technology (TUT) where working at home has been very common for a long time. The questionnaires were sent to academic personnel. The study shows that academic employees preferred teleworking for better concentration on work and saving time and money. There was no significant difference in telework usage by age and teleworkers had fewer complaints about tired eyes, arterial hypertension and stress.

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750-758 M. Hruška,, J. Kuchař, L. Libich and P. Jindra
Assessment of the impact of the shape of the handle on the ergonomics of operating a handbrake
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Assessment of the impact of the shape of the handle on the ergonomics of operating a handbrake

M. Hruška¹,*, J. Kuchař¹, L. Libich¹ and P. Jindra²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipments of Buildings, Kamýcká 129, CZ-16521 Prague 6 – Suchdol, Czech Republic; *Correspondence: jabko@tf.czu.cz 2Czech University of Life Sciences Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ-16521 Prague 6 – Suchdol, Czech Republic

Abstract:

This thesis addresses the ergonomic problem of conflict between hand-operated mechanical brakes and center rests on certain types of vehicles. The hand brake is one of the basic means of control of a personal vehicle and its smooth and comfortable mastery directly affects traffic safety and driver well-being. The paper outlines a possible solution to this problem through the shape of the mechanical handbrake handle. The proposed solution is validated by using Tecnomatix Jack, which is primarily intended for solving ergonomic problems in the context of Digital Human Modeling. Specifically, in order to verify the solution, the Comfort Assessment tool is used, which in itself contains several published studies looking at driver comfort in accordance with the bending of specific joints. The results of this thesis can be used for future mechanical handbrake designs in cars.

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759-764 P. Kic
Dust pollution in University offices
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Dust pollution in University offices

P. Kic

Czech University of Life Sciences Prague, Faculty of Engineering, Kamycka 129, CZ-16521 Prague 6, Czech Republic;
e-mail: kic@tf.czu.cz

Abstract:

The aim of this paper is to present results of microclimatic research focused mainly on dust pollution in several offices of Departments in the Faculty of Engineering at Czech University of Life Sciences Prague. The attention is paid to the dimensions of the room, floor covering, furniture, equipment, ventilation, frequency of the use and period of the year. In the frame of this research the concentration of air dust was measured by special exact instrument Dust-Track aerosol monitor. After the installation of different impactors the PM¹, PM².⁵, PM⁴, PM¹0 size fractions were also measured. The obtained results of measurements were evaluated by the statistical instruments and concentrations of different size of dust particles were analyzed. Results of different indoor conditions were generalized. Based on the results of measurements practical recommendations for the design, use, cleaning and ventilation of these types of rooms and buildings were summarised in the conclusions.

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765-774 T. Koppel, I. Vilcane, M. Carlberg, P. Tint, R. Priiman, K. Riisik, H. Haldre and L. Visnapuu
The effect of static magnetic field on heart rate variability – an experimental study
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The effect of static magnetic field on heart rate variability – an experimental study

T. Koppel¹*, I. Vilcane², M. Carlberg³, P. Tint¹, R. Priiman⁴, K. Riisik, H. Haldre⁴ and L. Visnapuu

¹Tallinn University of Technology, Department of Work Environment and Safety, Ehitajate tee 5, EE19086 Tallinn, Estonia; *Correspondence: tarmo.koppel@ttu.ee
²Riga Technical University, Institute of Occupational Safety and Civil Defence, Kalnciema Street 6, LV-1048 Riga, Latvia
³Department of Oncology, Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden 4Institute of Environmental Health and Safety

Abstract:

The aim of this study was to investigate the effect of weak static magnetic fields on human heart rate variability (HRV). So far, literature has mainly focused on the health effects induced by strong static magnetic fields. HRV is a temporal fluctuation of heart rate, which the literature has shown to be an adequate indicator for assessing the state of the autonomic nervous system. By autonomic nervous system one could also assess in real time if and when the organism falls into stress. In this blind experiment the subjects were exposed to 150 microTesla magnetic field for a few minutes. The heart activity of the subjects (n = 116) was recorded and the dynamics of the HRV frequency components i.e. reaction of the sympathetic and parasympathetic nervous system analyzed by repeated measures analysis of variance (ANOVA). No statistically significant difference (p < 0.05) were found in low frequency (LF), high frequency (HF), total power (TP), HF/TP ratio, LF/HF ratio nor between hear rate (HR) means in between the exposure and pre- or post-control stages of the experiment. However, observations made by the researchers suggest, that a small portion of the population may indeed be affected by slightly elevated static magnetic fields but the screening method needs further elaboration.

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775-785 E. Merisalu,, M. Vähi, S. Kinnas, M. Oja, K. Sarapuu, O. Novikov,M. Pärnapuu, E. Indermitte, K. Lea and H. Orru
Job specific risk factors, demographic parameters and musculoskeletal disorders among military personnel depending on type of service
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Job specific risk factors, demographic parameters and musculoskeletal disorders among military personnel depending on type of service

E. Merisalu¹,*, M. Vähi², S. Kinnas³, M. Oja⁴, K. Sarapuu⁵, O. Novikov⁵,M. Pärnapuu⁶, E. Indermitte⁷, K. Lea⁸ and H. Orru⁷

¹Institute of Technology, Estonian University of Life Sciences, Institute of Technology, Kreutzwaldi 56, EE51014 Tartu, Estonia; *Correspondence: eda.merisalu@emu.ee 2Institute of Mathematical Statistics, University of Tartu, Liivi 2, EE50409 Tartu, Estonia 3Institute of Physics, University of Tartu, Ravila 14c, EE50411 Tartu, Estonia 4Institute of Technology, University of Tartu, Nooruse 1, EE50411 Tartu, Estonia 5General Head Quarters, Estonian Defence Forces, Juhkendali 58, EE15007 Tallinn, Estonia 6Medical Centre, Medical Company, 1st Infantry Brigade, Estonian Defence Forces, Rae Põik 1, EE76806 Paldiski, Estonia 7Department of Public Health, University of Tartu, Ravila 19, EE50411 Tartu, Estonia; 8Civil Aviation Admisnistration, Estonia

Abstract:

Current study aimed to analyse the prevalence of job specific risk factors (JSRF) and musculoskeletal disorders (MSDs) among military personnel depending on demographic factors and type of service. An anonymous questionnaire study was carried out in five departments of Estonian Defence Forces (EDF) among local service personnel (LSP) and the Peace Corp personnel (PCP) arrived back from mission. The average response rate was 38.7% (LSP 31.9% and PCP 77.6%). In LSP group there were 44.7% male participants, with mean age 39.2 ± 11 years, length of service in present position 5.8 ± 4.9 years and work load of 37.9 ± 8.4 hours per week. In PCP group 97.4% were males, with mean age 27.5 ± 5.7 years, service length on present position 3.1 ± 2.6 years and work load of 84.3 ± 60.9 hours per week. The dominant JSRF in LSP was ‘demand for constant concentration’ (76.5%) and night work (57%) in PCP (group difference p < 0.0001). ‘Fast movements’ and ‘lifting loads >40 kg’ were the specific tasks most often reported in mission. ‘Job insecurity’ was more often reported by the female; ‘night work’ and ‘work-rest disbalance’ by the male military personnel (p< 0.001).The prevalence of MSDs was higher among women and LSP than in men and PCP group (p< 0.05). In LSP mild to moderate discomfort reported by 2/3 because of neck-shoulder strain and by ½ because of lower back pain. In conclusion, MSDs seems to depend more on demographic parameters and type of service than JSRFs. Further studies are needed to focus on predictive factors of MSDs among military personnel. Key words: job specific risk factors, demographic parameters, musculoskeletal disorders, military personnel.

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786-791 V. Nídlová, and J. Hart
Reliability of biometric identification using fingerprints under adverse conditions
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Reliability of biometric identification using fingerprints under adverse conditions

V. Nídlová¹,* and J. Hart²

¹Czech University of Life Sciences Prague (CULS), Faculty of Engineering, Department of Electrical Engineering and Automation, Kamýcká 129, CZ-16521 Prague, Czech republic; *Correspondence: nidlova@tf.czu.cz 2Czech University of Life Sciences Prague (CULS), Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ-16521 Prague, Czech republic

Abstract:

Biometric user identification is highly topical these days. The most well-represented method is fingerprint identification, to which this study is also dedicated. However, we cannot forget other methods such as scanning the bloodstream, retina and iris, facial recognition, etc. Four reading devices were tested in this study. Tests were carried out both under standard and adverse conditions. Adverse conditions included situations such as cold finger, cooled damp finger, heated finger, soaked finger, finger with a layer of instant glue, and dirty finger (soil). All tests performed under adverse conditions simulated realistic industrial plant environments. The results of the measurements showed that the measured reliability values do not correspond to those claimed by the manufacturers. It is necessary to adapt and perfect these biometric identification systems for use in industrial areas, as they are often used in these areas as access or attendance systems.

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792-809 Õ. Paas, K. Reinhold and P. Tint
Estimation of safety performance by MISHA method and the benefits of OHSAS 18001 implementation in Estonian manufacturing industry
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Estimation of safety performance by MISHA method and the benefits of OHSAS 18001 implementation in Estonian manufacturing industry

Õ. Paas*, K. Reinhold and P. Tint

Tallinn University of Technology, Faculty of Economics, Institute of Business Administration, Chair of Work Environment and Safety, Ehitajate 5, EE19086 Tallinn, Estonia; *Correspondence: onnela.paas@gmail.com

Abstract:

The paper concentrates on safety auditing as a tool for assessment of safety system and safety management in Estonian manufacturing enterprises. The aim of the research was to estimate the safety performance in Estonian manufacturing industry and explore the benefits of OHSAS 18001. Different available safety auditing methods are described. During 2014, 8 (OHSAS 18001-certified organisations) and 8 (non-certified organisations) Estonian enterprises from different branches of manufacturing were interviewed using MISHA method which is in accordance with the present requirements and is the most comprehensive. The results showed that non-certified organisations could be sub-divided into 2 categories: organisations which belong to a larger corporation or concern and locally established and owned companies. The latter showed the lowest scores as in these firms there are deficiencies in several OHS activity areas. Safety activities in a company depend strongly on consistency. Safety needs commitment and systematic approach. If one of the key elements of safety management system is missing, then it can be seen in the results of other framework elements. Our study demonstrates that OHSAS 18001 certificate automatically will not ensure high safety activities in the company. However, following the OHSAS 18001 standard gives a good incentive for a systematic safety activity in all levels in the company and promotes strong improvement process put in use. MISHA method can be successfully used for evaluating safety management systems in manufacturing industry, but it has to be kept in mind that some modifications may be needed due to national differences in safety activities. Key words: safety audit, safety management system, OHSAS 18001, safety performance, MISHA method.INTRODUCTION

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810-819 J. Paju and S. Kalle
An analysis of engineering students’ knowledge on the topic of occupational health and safety
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An analysis of engineering students’ knowledge on the topic of occupational health and safety

J. Paju* and S. Kalle

Tallinn University of Technology, Tallinn School of Economics and Business Administration, Department of Business Administration, Academia road 3, EE12618 Tallinn, Estonia; *Correspondence: jana.paju@ttu.ee

Abstract:

Occupational health problems often result of poor knowledge of safety requirements and inadequate personnel training, especially considering specific tasks at work. A questionnaire was distributed to university students to respond, in order to analyse their answers and achieve following objectives: (1) to pinpoint the students’ knowledge prior to the start of the course; (2) to reveal how many students have had experience with occupational health and safety (OHS) topics before starting the course; (3) to determine whether the knowledge of students with prior experience is greater; (4) to identify the most difficult topics or domains. The obtained results showed that the average test score was 50.2% (n = 151). Students with prior knowledge on OHS (n = 53) did not get higher test scores (p-value = 0.12; α = 0.05). The objectives of the study were achieved. Further studies considering the efficiency of both teaching and learning are to be conducted.

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820-828 V. Pille, V.-R. Tuulik, S. Saarik, P. Tint,, T. Vare and R. Sepper
Work-related musculoskeletal symptoms in industrial workers and the effect of balneotherapy
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Work-related musculoskeletal symptoms in industrial workers and the effect of balneotherapy

V. Pille¹, V.-R. Tuulik², S. Saarik², P. Tint¹,*, T. Vare² and R. Sepper¹

¹Tallinn University of Technology, Ehitajate 5, EE19086 Tallinn, Estonia 2Tallinn University Haapsalu College, Lihula 1, EE90507 Haapsalu, Estonia *Correspondence: piia.tint@ttu.ee

Abstract:

The aim of the paper is to present balneotherapy (mud treatment) effect in the rehabilitation and prevention of work-related musculoskeletal disorders (MSDs) of industrial workers. Balneotherapy significantly reduces the muscle pain complaints of the employees. The m.abductor pollicis brevis muscle tension measured decreased after the balneotherapy. The study included overall 114 industrial workers (91 female and 23 male persons from garment and woodworking industries) with professional overuse of the upper extremities. The average age of the workers was 49.1 (from 22 to 75) years, their average length of the service was 16.2 years. The main result of the questioning of the workers about the pain regions: there was quite a high incidence of musculoskeletal pain in the investigated workers with a work-related upper extremity syndrome: neck 68.4%, shoulders 63.2%, elbows 42.1% and wrists 78.9%. In the course of the study, balneotherapy was applied to 19 (13 female and 6 male) industrial workers who had pain at least in two regions of the body. The average age of these workers was 50.6 years and the average length of the service 21.3. After the balneotherapy, the 19 industrial workers’ complaints of pain in the neck and in the wrists decreased from 2.37 to 1.13 points (p = 0.05) and from 3.25 to 1.03 points (p = 0.007) respectively on the VAS pain scale. Objective measurement of muscle fatigue with a myotonometer showed the decrease in the stiffness of hand muscles (Abd poll brev, right: from 278 nM-1 until 342 nM-1, p = 0.006). The results indicated that more attention should be paid to the early diagnostics and preventive measures. Key words: physical overload, musculoskeletal disorders, myotonometry, industrial workers, balneotherapy.INTRODUCTION AND THEORETICAL BASIS

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829-835 I. Roja, Z. Roja and H. Kalkis,
Team learning and self-management for video display terminal employees with chronic neck-shoulders pain
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Team learning and self-management for video display terminal employees with chronic neck-shoulders pain

I. Roja¹, Z. Roja² and H. Kalkis²⋅³,*

¹Outpatient Department, Riga 1st Hospital; Bruninieku 5, LV-1005 Riga, Latvia 2Ergonomics Research Centre, University of Latvia; Kr. Valdemara 48, LV-1013 Riga, Latvia 3Faculty of Economics and Management, University of Latvia; Aspazijas blvd. 5, LV-1050 Riga, Latvia; *Correspondence: henrijs.kalkis@lu.lv

Abstract:

In Latvia occupational musculoskeletal disorder – chronic neck-shoulders pain (NSP) – is a common complaint in the general population, also in video display terminal (VDT) employees in their giving age, working in bank and agriculture system, and such patients with chronic NSP load markedly the public health care service. The biopsychosocial influence on pain for VDT employees is team learning (TL) with self-management (SM) strategies: pain-blocking imagery, mind-body relaxation, cognitive restructuring of unpleasant physical and emotional experience, improvement of workplace relations and organizational culture. The aim of the research was to evaluate the effectiveness of using TL and SM one month course for bank and agricultural advisory services VDT employees, females and males, suffering from chronic moderate NSP. The structured self-administrated questionnaire was carried out to find out which body parts suffer from pain during workload, information on work-related ergonomic and psychosocial risk factors was collected during face to face interviews. During testing for TL and SM course with follow-up assessment was selected 21 VDT employees (females = 11, males = 10; age between 22 and 50). The intensity of NSP was determined by using the Numeric Pain Rating Scale (NPRS), life quality assessment was analysed with Quality of Life Scale (QOLS), p-value, confidence interval was calculated. Patients were asked to keep a Pain Diary during treatment course. The results indicated decrease in neck-shoulders pain intensity, and positive quality of life changes after TL and SM intervention in video display terminal (VDT) employees. Statistically significant reduction in pain intensity after TL and SM intervention by the biopsychosocial influence on pain according NPRS was among males, and the life quality according to QOLS score – among females. The necessity to perform patient’s objective clinical examinations, subjective tests of self-esteem, to keep a Pain Diary during treatment course has been proved in our research. Key words: chronic moderate neck-shoulders pain, video display terminal employees, team learning, self-management.INTRODUCTION

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836-845 J. Sepp, M. Järvis, P. Tint, V. Siirak and Reinhold, K.
EMG measurements of thumb muscles of nurses and caregivers
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EMG measurements of thumb muscles of nurses and caregivers

J. Sepp¹*, M. Järvis², P. Tint², V. Siirak² and Reinhold, K.²

¹Tallinn Health Care College; Tallinn University of Technology, Faculty of Economics, Institute of Business Administration, Ehitajate 5, EE19086 Tallinn, Estonia 2Tallinnn University of Technology, Faculty of Economics, Institute of Business Administration, Ehitajate 5, EE19086 Tallinn, Estonia *Correspondence: jaana.sepp@ttk.ee

Abstract:

The number of ageing people in Estonia is increasing. Convenience for personnel in the nursing homes for the elderly and enabling high-quality care is essential. This includes new work methods to relieve the physical burden of nursing workers and the mental stress decreasing interventions. In the theoretical part of the paper, the physical and psychosocial risk factors of nurses and caregivers are dealt with. The aim of the study is to measure the m. abductor pollicis brevis fatigue in connection with the physical stress of nurses and caregivers. The experimental part of the paper concentrates on the physical stress factors. Electromyography (eMotion EMG) is used as the method for the determination of the nursing workers’ thumb muscle’s (m. abductor pollicis brevis) fatigue. The results show the linear dependences between the level of fatigue of the thumb muscles at the beginning and at the end of an 8-hour workday; between the EMG signals from the muscles in the resting state and after a 5-minute strained state. The interviews with the nurses showed that the renewal of equipment and rooms in the nursing homes is the main factor to prevent the physiological stress at workplaces (pain in the hands, low back pain etc.). In the newly built nursing homes with modern equipment, the workers are satisfied and no physiological stress was noticed. Key words: psychological stress, fatigue, nursing homes, nurses working conditions, job satisfaction.INTRODUCTION AND THEORETICAL BASIS

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846-855 I. Vilcane, V. Urbane, P. Tint, J. Ievins
The comparison study of office workers’ workplace health hazards in different type of buildings
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The comparison study of office workers’ workplace health hazards in different type of buildings

I. Vilcane¹, V. Urbane¹, P. Tint²⋅*, J. Ievins¹

¹Riga Technical University, Faculty of Economics, Institute of General and Civil Safety, Kalnciema Str. 6, LV-1048 Riga, Latvia 2Tallinn University of Technology, Faculty of Economics, Department of Work Environment and Safety, Ehitajate 5, EE19086 Tallinn, Estonia; *Correspondence: piia.tint@ttu.ee

Abstract:

The aim of the study is to investigate the office-workers’ working conditions in the ordinary and atrium-type buildings. The indoor climate conditions in the cold season in two type of university buildings are presented. The air temperature is on the good level in the both of the buildings. The rooms in the atrium-side of the building A are too tight and the ergonomics is not considered designing the workplaces in the office-rooms. In the auditoriums of the building B it is too noisy (over 70 dB(A)) during the breaks that prevents the rest and the communication between the workers and students. The air humidity is too low in both type of the buildings (< 30% in the cold season, when the rooms are central-heated). It is recommended to moisten the air in the rooms artificially. For the health risk assessment in the workrooms a flexible risk assessment model is used. The risk levels for the indoor climate factors are different in the two type of buildings.

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