Research of Operational Properties of Household Fabrics for Production of Protective Masks

2021 ◽  
Vol 1038 ◽  
pp. 221-232
Author(s):  
Serhii Cheberiachko ◽  
Ivan Knysh ◽  
Dmytro Pustovoi ◽  
Olena Sharovatova
Keyword(s):  
Experimental Study ◽  
Protective Action ◽  
Experimental Studies ◽  
Breathing Resistance ◽  
Paraffin Oil ◽  
Two Samples ◽  
Physiological Impact ◽  
The Relationship ◽  
Penetration Coefficient

Experimental studies have been conducted to determine the operational properties of fabrics used for the manufacture of protective masks. For the experimental study, 22 different fabrics were used, which are available in everyday life. Determination of the operational properties was carried out according to three indicators: the penetration coefficient of the test aerosol, paraffin oil (filtering property), breathing resistance (ergonomic property), resistance to dusting (protective action period) in accordance with the requirements of DSTU EN 149-2017 standard. According to the results of the experimental study to determine the operational properties of fabrics: breathing resistance, penetration coefficient and resistance to dust, it was found that out of the twenty-two samples tested, only eight can be used for the manufacture of protective masks, since their characteristics are able to provide a sufficient level of protection from minimal physiological impact on human (wool, two-thread cloth, velor, tricotin, jersey, frieze and satin). Theoretical calculation of the operational properties of protective masks, which can be made of these fabrics, based on experimental data allowed to make their compliance with the first class of protection according to the requirements of DSTU EN 149-2017. The scientific novelty is to clarify the relationship between the operational properties of fabrics and the operational properties of protective masks.

DETERMINATION OF THE INFLUENCE OF STRUCTURAL ELEMENTS ON ACOUSTIC EFFICIENCY AND BACK PRESSURE IN EXHAUST AND SUCTION NOISE SILENCERS

Akustika ◽  
2021 ◽  
pp. 210-216
Author(s):  
Nickolay Ivanov ◽  
Aleksandr Shashurin ◽  
Aleksandr Burakov
Keyword(s):  
Structural Design ◽  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Back Pressure ◽  
Noise Generation ◽  
Structural Elements ◽  
The Relationship

The features of noise generation processes in exhaust and suction noise silencers are shown. A method for testing silencers has been developed. The classification of the main structural elements of exhaust and suction noise silencers, depending on the purpose, is proposed. Experimental studies of the relationship between the acoustic efficiency and the back pressure of silencers from the structural design of the elements are performed. The factors influencing the efficiency in the low-frequency and high-frequency regions of the spectrum are determined: the volume of silencers, the number of chambers, perforation, sound absorption, flow ejection, etc. Recommendations for the design of noise silencers are proposed.

Predicting Crack-Formation Life

1979 ◽  
Vol 21 (4) ◽  
pp. 263-273 ◽  
Author(s):  
T. V. Duggan ◽  
M. T. Lowcock ◽  
B. C. Staples
Keyword(s):  
Strain Gradient ◽  
Crack Formation ◽  
Experimental Studies ◽  
Strain Gradients ◽  
Local Material ◽  
Strain Gradient Effects ◽  
Predicted Values ◽  
The Relationship ◽  
Gradient Effects

This paper discusses the parameters likely to influence the crack-formation life of components. In particular, the relationship between the fatigue life of plain and notched specimens is considered, and a mathematical model for predicting the crack-formation life of components is proposed. This allows for the effects of mean stresses and strains and is dependent upon the determination of local material behaviour. The approach is original in that it makes allowances for the influence of the degree of plasticity around a notch, represented in terms of the strain gradient. The Neuber method is evoked, suitably modified to allow for strain gradient effects, and strain gradients are estimated by differentiating Neuber's rule in the immediate vicinity of the notch. Experimental studies have been conducted to determine strain distributions, strain gradients and cyclic lives, and the results compared with predicted values; correlation is good.

scholarly journals EXPERIMENTAL DETERMINATION OF THE LEVEL OF INCIPIENT TURBULENCE IN THE WORKING PART OF THE T-1 WIND TUNNEL OF IVAN KOZHEDUB KHARKIV NATIONAL AIR FORCE UNIVERSITY

2021 ◽  
Vol 5 (2) ◽  
pp. 98-102
Author(s):  
Віталій Бездєльний ◽  
Сергій Шевченко ◽  
Ілля Грідасов
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Wind Tunnel ◽  
Experimental Determination ◽  
Air Force ◽  
Normal Condition ◽  
Aerodynamic Drag ◽  
Experimental Studies ◽  
The Subject

The subject of the article is to determine the level of incipient turbulence in the wind tunnel T-1 which is based on the method of measuring the pressure drop. The purpose is to experimentally determine the level of incipient turbulence in the working part of wind tunnel T-1 of Ivan Kozhedub Kharkiv National Air Force University in preparation for aerodynamic testing of aircraft models. Research methods: the method of pressure drop on the surface of the sphere by drainage. The following results of experimental determination of the level of incipient turbulence in the wind tunnel T-1 were obtained. It is established that the wind tunnel T-1 has a level of incipient turbulence 0,5…0,9 %, which corresponds to the normal condition for further experimental studies. Conclusions. According to the results of studies of the incipient turbulence in the wind tunnel T-1 by the method of pressure drop, the main dependences are obtained, and the incipient turbulence of the flow for the wooden sphere x = 0,9 %, and for the metal sphere x = 0,5 %, is determined. Determining the pressure distribution and aerodynamic drag does not involve measures to balance the aerodynamic scales and their certification, which determines the necessary role in the obtained reliable results of the experimental study, and this favors the drainage method.

scholarly journals Determination of working parameters of measure to ensure metrological research tribological characteristics of plain bearings

2017 ◽  
Vol 6 (2) ◽  
pp. 123-129
Author(s):  
Серебрянский ◽  
Aleksey Serebryanskiy
Keyword(s):  
Experimental Study ◽  
Experimental Studies ◽  
Design Parameters ◽  
Laboratory Equipment ◽  
The Real ◽  
Metrological Research ◽  
Real Size ◽  
Working Parameters ◽  
Conditions Of Work

The characteristics of plain bearings used in the industry are given in the article. The directions that increase their ser-vice life are defined. The need for experimental studies of bearing is justified, and laboratory equipment is offered. Experimental study of bearings is necessary to verify calculations and to determine the effect of changing some design parameters on their work as well. It is usually difficult or even impossible to experience the bearing in the real size and under conditions identical to real conditions of work.

scholarly journals Determination of drying behaviour in industrial type convectional dryer and mathematical modelling

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 1935-1950 ◽  
Author(s):  
Ahmet Akan ◽  
Derya Ozkan
Keyword(s):  
Experimental Study ◽  
Mathematical Modelling ◽  
Diffusion Model ◽  
Diffusion Coefficients ◽  
Experimental Studies ◽  
Activation Energies ◽  
Second Law ◽  
Hot Air ◽  
Drying Behaviour

In this study, the performance of a stenter (ram machine) that enables the drying of textile products with hot air is theoretically modelled with a diffusion model derived from Fick?s second law. The experimental study was conducted in a 10 chamber stenter with three different drying temperatures (110-130-150?C) and three different fabric speeds (10-20-30 m per minute.) by using a fabric consisting of 95% cotton + 5% lycra. The drying behaviour of the dryer was determined by utilizing the data obtained from the studies. With the help of the utilized model, the values of diffusion coefficients and activation energies were obtained, the conformity of data between the model and the experimental studies were compared by using regres

A Comprehensive Analysis of Various Structural Parameters of the Untreated Calcium Phosphate from Two Moroccan Mining Zones

2020 ◽  
Vol 18 (4) ◽  
pp. 268-272
Author(s):  
Ikram Labtaini ◽  
Khalil El-Hami
Keyword(s):  
Calcium Phosphate ◽  
Structural Parameters ◽  
Xrd Analysis ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Raman Analysis ◽  
Two Samples ◽  
Structural Differences ◽  
The Relationship

X-ray diffraction (XRD) and Raman spectroscopy analyses were performed on untreated calcium phosphate samples of the two mining zones of Morocco: Benguerir and Khouribga. XRD has been examined for the determination of the structure parameters and their textures. However, a comparative study was conducted between the two types of phosphate to implement the observed structural differences. XRD Results showed that the comparison between the two samples reveals significant differences at the level of the refinement parameters, crystallite size and microstrain but no changes in the crystal system. Raman analysis assignments are given for powdered samples of the organically important compound, calcium phosphate, in the 0–3600 cm–1 range. The wavenumber positions of Raman bands were different and changed between the two different samples. The results may be of significance in understanding the relationship between XRD analysis and the parameters of material structure.

Thromboplastin Related Differences in the Determination of International Normalised Ratio: A Cause for Concern?

1994 ◽  
Vol 72 (03) ◽  
pp. 426-429 ◽  
Author(s):  
S Kitchen ◽  
I D Walker ◽  
T A L Woods ◽  
F E Preston
Keyword(s):  
Patient Management ◽  
External Quality Assessment ◽  
Oral Anticoagulant Therapy ◽  
Warfarin Dosage ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
International Normalised Ratio ◽  
The Uk ◽  
The Relationship

SummaryWhen the International Normalised Ratio (INR) is used for control of oral anticoagulant therapy the same result should be obtained irrespective of the laboratory reagent used. However, in the UK National External Quality Assessment Scheme (NEQAS) for Blood Coagulation INRs determined using different reagents have been significantly different.For 18 NEQAS samples Manchester Reagent (MR) was associated with significantly lower INRs than those obtained using Diagen Activated (DA, p = 0.0004) or Instrumentation Laboratory PT-Fib HS (IL, p = 0.0001). Mean INRs for this group were 3.15, 3.61, and 3.65 for MR, DA, and IL respectively. For 61 fresh samples from warfarin-ised patients with INRs of greater than 3.0 the relationship between thromboplastins in respect of INR was similar to that observed for NEQAS data. Thus INRs obtained with MR were significantly lower than with DA or IL (p <0.0001). Mean INRs for this group were 4.01, 4.40, and 4.59 for MR, DA, and IL respectively.We conclude that the differences between INRs measured with the thromboplastins studied here are sufficiently great to influence patient management through warfarin dosage schedules, particularly in the upper therapeutic range of INR. There is clearly a need to address the issues responsible for the observed discrepancies.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

Modern determinants of endometrium hyperplastic processes pathogenesis

2016 ◽  
pp. 137-142
Author(s):  
V.O. Benyuk ◽  
◽  
V.M. Goncharenko ◽  
T.R. Nykoniuk ◽  
◽  
...  
Keyword(s):  
Conservative Therapy ◽  
Solid Phase ◽  
Research Direction ◽  
Immunohistochemical Method ◽  
Results Of Treatment ◽  
Treatment And Prevention ◽  
Receptor Phenotype ◽  
The Relationship ◽  
Endometrial Proliferation

The objective: to еxplore the relationship between the activity of endometrial proliferation and the state of the local immune response in the uterus in the conditions berprestasi process. Patients and methods. Examined 228 women of reproductive and perimenopausal age with endometrial pathology using ultrasound and then performing hysteroresectoscopy. Determination of the concentrations of the cytokines IL-1, IL-2, IL-6 and TNF was performed by solid phase ELISA. Results. Found a trend that confirms the loss of sensitivity to hormones at the stage of malignancy of the endometrium and can be used as diagnostic determinants in determining the nature of intrauterine pathology and criterion of the effectiveness of conservative therapy. Conclusion. Improving etiopatogenetice approach to the therapy of hyperplastic proce.sses of endometrium with determination of receptor phenotype of the endometrium is a research direction in modern gynecology, which will help to improve the results of treatment and prevention of intrauterine pathology. Key words: endometrial hyperplasia,the receptors for progesterone and estrogen, immunohistochemical method.

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