scholarly journals Obudowy dźwiękochłonno-izolacyjne urządzeń ultradźwiękowych, ograniczające poziom hałasu przenikającego do środowiska. Wyniki badań własnych

2021 ◽  
Vol 600 (9) ◽  
pp. 22-28
Author(s):  
Witold Mikulski ◽  
Keyword(s):  
Health Risk ◽  
Frequency Range ◽  
Effective Measure ◽  
Close Proximity ◽  
Ultrasonic Devices ◽  
Materials Used ◽  
Technical Solutions ◽  
The Impact

The article discusses the technical solutions of sound-absorbing and sound-insulating enclosures for devices that are sources of ultrasonic noise (sound frequencies range of 10-40 kHz). Due to the high health risk of employees operating ultrasonic technological devices and the fact that they are in close proximity to these devices, it is necessary to use an effective measure to reduce this risk, i.e. sound-insulating enclosures. So far, however, the rules for the use of such casings and the sound-insulating and sound-absorbing properties of their materials (in this frequency range) have not been defined. The article presents the results of own research on the impact of the materials used to make enclosures, linings of casings and the presence of openings (hole) in casings on the level of noise emitted by ultrasonic devices that penetrates into the environment.

Three-layer Permutation of the Phonionic Structure and the Influence of the Environment

2018 ◽  
Vol 69 (9) ◽  
pp. 2571-2574
Author(s):  
Michal Szota
Keyword(s):  
Layer Structure ◽  
Middle Layer ◽  
Production Costs ◽  
Frequency Range ◽  
Different Types ◽  
Transmission Structure ◽  
Materials Used ◽  
The Impact ◽  
Wave Filters ◽  
Different Thickness

The study investigated the influence of permutation of a three-layer structure on the phononic system transmission. Phononic structures are used as mechanical wave filters. These composites are designed and manufactured to have specific properties. The most important property is the presence of phononic bandgaps (PhBG) in these structures. They are designed so that the PhBG occurs in a given frequency range. Knowledge of the impact of deployment of the layets in the structure allows better design of these filters. The analysis was carried out using the transmission matrix method (TMM) algorithm. The transmission structures was examined for all permutations of a system of three layers made of different materials. The structure consisted of mercury, epoxy, rubber and PNM-0.38PT. The materials are chosen so that their characteristics largely differ. The structure was surrounded by water. The tests were carried out for the frequency range up to 1 MHz. Cases with different thickness of layers were analyzed. The tests have shown that regardless of the layer thickness, only three types of transmission structures exist in the six permutations of the system. Systems in which the middle layer remained unchanged, while the outermost layers were changed, were characterized by the same transmission structure. Increasing the thickness of the layers increased the number of transmission bands. Transmission strongly depends on the environment.The absorption of the materials used was not taken into account in the work. Interesting results can be obtained by analyzing the permutation of more complex structures. Changing the order of layers in the filter without changing its characteristics may affect the reduction of production costs and easier design of structures with given properties. The article shows repeating phononic transmission structure for different types of layers alignment.

Peculiarities of tool material wear at polymeric composite blank cutting

2018 ◽  
Vol 2018 (7) ◽  
pp. 27-31
Author(s):  
Юрий Зубарев ◽  
Yuriy Zubarev ◽  
Александр Приемышев ◽  
Alexsandr Priyomyshev
Keyword(s):  
Tool Wear ◽  
Tool Material ◽  
Polymeric Composite ◽  
Physical Models ◽  
Technological Parameters ◽  
Tool Materials ◽  
Materials Used ◽  
The Impact ◽  
Material Wear

Tool materials used for polymeric composite blank machining, kinds of tool material wear arising at machining these blanks, and also the impact of technological parameters upon tool wear are considered. The obtained results allow estimating the potentialities of physical models at polymeric composite blanks cutting.

scholarly journals Aspects of Strength Testing of Tank Containers in Compliance with the Requirements of the UN Navigation Rules and Regulations

2021 ◽  
Vol 9 (3) ◽  
pp. 349
Author(s):  
Andrii Sulym ◽  
Pavlo Khozia ◽  
Eduard Tretiak ◽  
Václav Píštěk ◽  
Oleksij Fomin ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Response Spectrum ◽  
Experimental Curve ◽  
Bulk Liquid ◽  
Frequency Range ◽  
Test Configuration ◽  
Shock Response ◽  
Shock Response Spectrum ◽  
Spectrum Curve ◽  
The Impact

This article deals with the method of computer-aided studies of the results of tank container impact tests to confirm the ability of portable tanks and multi-element gas containers to withstand the impact in the longitudinal direction on a specially equipped test rig or using a railway flat car by impacting a flat car with a striking car, in compliance with the requirements of the UN Navigation Rules and Regulations. It is shown that the main assessed characteristic of the UN requirements is the spectrum of the shock response (accelerations) for the interval natural frequencies of the shock pulse. The calculation of the points of the shock response spectrum curve based on the test results is reproduced in four stages. A test configuration of the impact testing of the railway flat car with a tank container is presented, and the impact is performed in such a way that, under a single impact, the shock spectrum curve obtained during the tests for both fittings subjected to impact repeats or exceeds the minimum shock spectrum curve for all frequencies in the range of 2 Hz to 100 Hz. Formulas for determining the relative displacements and accelerations for the interval natural frequencies of the shock wave are given. The research results are presented in graphical form, indicating that the experimental values of the shock response spectrum exceed the minimum permissible values; the equation of the experimental curve of the shock response spectrum in the frequency range 0–100 Hz is described by power-law dependence. The coefficients of the equation were determined by the statistical method of maximum likelihood with the determination factor being 0.897, which is a satisfactory value; a comparative analysis showed that the experimental curve of the impact response spectrum in the frequency range 0–100 Hz exceeds the normalized curve, which confirms compliance with regulatory requirements. A new test configuration is proposed using a tank car with a bulk liquid, the processes in which upon impact differ significantly from other freight wagons under longitudinal impact loads of the tank container. The hydraulic impact resulting from the impact on the tank container and the platform creates an overturning moment that causes the rear fittings to be unloaded.

scholarly journals Health risk assessment and countermeasure analysis of the elderly population exposed to PM2.5 microenvironment

Work ◽  
2021 ◽  
pp. 1-11
Author(s):  
Yan Xu ◽  
Wantian Cui
Keyword(s):  
Mental Health ◽  
Health Risk ◽  
Elderly Population ◽  
Mental Health Problems ◽  
Negative Impact ◽  
The Elderly ◽  
Exposure Concentration ◽  
Physical Diseases ◽  
The Impact

BACKGROUND: China’s atmospheric PM2.5 pollution is serious, and PM2.5 exerts a negative impact on the human respiratory system, cardiovascular, and mental health, and even more serious health risk for the elderly with weak immunity. OBJECTIVE: This work aims to analyse the impacts of PM2.5 microenvironment exposure on the health of the elderly and provide corresponding countermeasures. METHODS: The survey subjects are 118 retired elderly people in the community. PM2.5 exposure concentrations are monitored in summer (June 10 ∼ July 10, 2019) and winter (November 25 ∼ December 25, 2019). RESULTS: The exposure concentration in winter is higher than that in summer, with statistical difference (P <  0.05). Under the impact of PM2.5 microenvironment exposure, smoking in the elderly can increase the concentration of PM2.5, and long-term exposure to PM2.5 in the elderly can cause mental health problems. CONCLUSION: Long-term exposure of the elderly to the PM2.5 microenvironment leads to physical diseases and even psychological problems, which requires attention.

scholarly journals A review of challenges and benefits of integration of CHP plant into the grid: a case study in Serbia

2021 ◽  
Author(s):  
Rade M. Ciric ◽  
Sasa N. Mandic
Keyword(s):  
Energy Efficiency ◽  
Negative Impact ◽  
Renewable Energy Sources ◽  
Increase Energy Efficiency ◽  
High Voltage Supply ◽  
The Republic ◽  
Technical Solutions ◽  
The Impact

AbstractThe Republic of Serbia must make significant efforts to promote and exploit renewable energy sources and increase energy efficiency in all energy sectors to ensure energy security and economic competitiveness, reduce the negative impact on the environment from energy production and use, and contribute to global efforts to reduce greenhouse gases. Within the paper several issues of integration of recently realized CHP plant are introduced and discussed. Firstly, the legal and energy policy issues in the Republic of Serbia regarding connecting CHP to the grid are presented. The challenges and technical solutions for CHP connection to the grid, as well as power quality issues and the role of the CHP plant during the restoration of power supply during the maintenance of the substation and unplanned loss of high voltage supply, are presented and discussed. Finally, the impact of prospective massive integration of CHP on the energy balance and CO2 emission reduction in the province of Vojvodina in Serbia is investigated and discussed. Since it is the first CHP plant realized in Serbia, it is crucial that experience be shared to all potential stakeholders in the future energy efficiency projects.

scholarly journals Analysis of the Impact on the Mechanical Properties of Modification of Oligohydroxyethers in Organic Solvent Solution with Rubbers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 519
Author(s):  
Vitalii Bezgin ◽  
Agata Dudek ◽  
Adam Gnatowski
Keyword(s):  
Mechanical Properties ◽  
Scientific Paper ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Molecular Weights ◽  
Wide Range ◽  
Strength Tests ◽  
Materials Used ◽  
Styrene Butadiene ◽  
The Impact

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.

The impact of energy refurbishment interventions on annual energy demand, indoor thermal behaviour and temperature-related health risk

Energy Policy ◽  
2021 ◽  
Vol 153 ◽  
pp. 112276
Author(s):  
Matxalen Etxebarria-Mallea ◽  
Xabat Oregi ◽  
Olatz Grijalba ◽  
Rufino Hernández-Minguillón
Keyword(s):  
Health Risk ◽  
Thermal Behaviour ◽  
Energy Demand ◽  
The Impact

scholarly journals Are Biogenic and Pyrogenic Mesoporous SiO2 Nanoparticles Safe for Normal Cells?

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1427
Author(s):  
Katarzyna Solarska-Ściuk ◽  
Kinga Adach ◽  
Sylwia Cyboran-Mikołajczyk ◽  
Dorota Bonarska-Kujawa ◽  
Agnieszka Rusak ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Biological Effects ◽  
Mesoporous Silica Nanoparticles ◽  
Volume Ratio ◽  
Sio2 Nanoparticles ◽  
Amorphous Structure ◽  
Intracellular Ros ◽  
Materials Used ◽  
The Impact

Silicon dioxide, in the form of nanoparticles, possesses unique physicochemical properties (size, shape, and a large surface to volume ratio). Therefore, it is one of the most promising materials used in biomedicine. In this paper, we compare the biological effects of both mesoporous silica nanoparticles extracted from Urtica dioica L. and pyrogenic material. Both SEM and TEM investigations confirmed the size range of tested nanoparticles was between 6 and 20 nanometers and their amorphous structure. The cytotoxic activity of the compounds and intracellular ROS were determined in relation to cells HMEC-1 and erythrocytes. The cytotoxic effects of SiO2 NPs were determined after exposure to different concentrations and three periods of incubation. The same effects for endothelial cells were tested under the same range of concentrations but after 2 and 24 h of exposure to erythrocytes. The cell viability was measured using spectrophotometric and fluorimetric assays, and the impact of the nanoparticles on the level of intracellular ROS. The obtained results indicated that bioSiO2 NPs, present higher toxicity than pyrogenic NPs and have a higher influence on ROS production. Mesoporous silica nanoparticles show good hemocompatibility but after a 24 h incubation of erythrocytes with silica, the increase in hemolysis process, the decrease in osmotic resistance of red blood cells, and shape of erythrocytes changed were observed.

scholarly journals Green Packaging from Consumer and Business Perspectives

2021 ◽  
Vol 13 (3) ◽  
pp. 1356
Author(s):  
Gonzalo Wandosell ◽  
María C. Parra-Meroño ◽  
Alfredo Alcayde ◽  
Raúl Baños
Keyword(s):  
Sustainable Development ◽  
Raw Materials ◽  
Research Activity ◽  
Word Clouds ◽  
Climate Action ◽  
Green Packaging ◽  
Materials Used ◽  
Societal Challenge ◽  
Corporate Social ◽  
The Impact

Sustainable development is a global objective that aims to address the societal challenge of climate action, the environment, resource efficiency, and raw materials. In this sense, an important strategy is the promotion of green packaging, that is, the use of sustainable materials and designs for the packaging of goods. In recent years, many research works have been published in the specialised area covering the different perspectives and dimensions of green packaging. However, to our knowledge, no previous investigations have analysed the research activity on green packaging from business and consumer perspectives. The present study intends to fill this gap by analysing all of the publications found in the Scopus database with the help of visual analytic tools, including word clouds and Gephi network visualization software. More specifically, our study analyses the impact of green packaging from business and consumer viewpoints, including some specific issues such as the design and materials used in green packaging, green packaging costs, marketing strategies and corporate social responsibility related to green packaging, and the impact of green packaging in waste management, the circular economy, logistics, and supply chain management. The results obtained reveal the growing interest of scholars and researchers in all of these dimensions, as is made patently clear by the increasing number of journal publications in recent years. The practical implications of this study are significant, given the growing awareness among companies and consumers about the importance of the promotion of sustainable development through green packaging alternatives. More specifically, the results of this research could be very useful for all of those agents who are interested in learning about the main lines of research being developed in the field of green packaging.

The impact attenuation performance of materials used under indoor playground equipment at child care centers

2001 ◽  
Vol 8 (1) ◽  
pp. 45-47 ◽  
Author(s):  
Mick Mack ◽  
Jeffrey Sacks ◽  
Susan Hudson ◽  
Donna Thompson
Keyword(s):  
Child Care ◽  
Child Care Centers ◽  
Impact Attenuation ◽  
Materials Used ◽  
The Impact
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