Modeling airborne nanoparticle filtration through a complete structure of non-woven material used in protective apparel

2018 ◽  
Vol 89 (15) ◽  
pp. 3024-3033
Author(s):  
Ludwig Vinches ◽  
Ludovic Tuduri ◽  
Stéphane Hallé
Keyword(s):  
Significant Proportion ◽  
Experimental Studies ◽  
Protective Equipment ◽  
Respiratory Protection ◽  
Local Effects ◽  
Complete Structure ◽  
Proposed Model ◽  
Airborne Nanoparticles ◽  
Airborne Nanoparticle ◽  
Domain Of Validity

Airborne nanoparticles represent a new danger in occupational health. Numerous theoretical and experimental studies have been conducted on the efficiency of filtering media used for respiratory protection, but few have focused on media used for skin protective equipment. Indeed, a significant proportion of airborne nanoparticles can end up on the skin, causing local effects and eventually penetrating the human body. Following experimental data obtained with sodium chloride nanoparticles, the authors propose an empirical model to evaluate the penetration of airborne nanoparticles through medium used in disposable coveralls. This study presents an adaptation of the conventional filtration theory used for filtering media used in respirators. The authors' model is compared with Wang et al.'s and Brochot's models and demonstrates improvements in their descriptive ability. Moreover, a domain of validity of the proposed model was determined that will enable the evaluation of the efficiency of similar protective apparel material structures against airborne nanoparticles.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

scholarly journals Use of Respiratory Protection Devices by Medical Students During the COVID-19 Pandemic

2021 ◽  
Vol 18 (11) ◽  
pp. 5834
Author(s):  
Ekaterina A. Shashina ◽  
Valentina V. Makarova ◽  
Denis V. Shcherbakov ◽  
Tatiana S. Isiutina-Fedotkova ◽  
Nadezhda N. Zabroda ◽  
...  
Keyword(s):  
Medical Students ◽  
Face Mask ◽  
Protective Measure ◽  
Protective Equipment ◽  
Respiratory Protection ◽  
Prevention Measures ◽  
Protection Devices ◽  
Individual Use

The use of face masks has assumed a leading spot among nonspecific prevention measures during the coronavirus pandemic. The effectiveness of this protective measure depends on the specifics of individual use. The purpose of our study was to analyze the use of respiratory protective equipment (RPE) by medical students during the COVID-19 pandemic. The evaluation of face mask use was based on the results of a survey of medical students at Sechenov University. There were 988 participants in the study: 97.5% used RPE during the pandemic, 89.1% used disposable medical and hygienic face masks, 27.4% used reusable cloth face masks, and 13.2% used respirators. The majority of respondents (75.2%) were found to wear face masks correctly. However, 17.0% of the respondents were found to cover only their mouths with a face mask, while 7.8% reported often shifting their face mask under the chin due to perceived discomfort. Only 25.1% of respondents changed their disposable face mask after 2-3 h of wearing, while 13.0% decontaminated and used it several times. Most cloth face mask users (93.7%) decontaminated their marks, but only 55.7% of respondents did so daily. Face masks were most often worn in medical organizations (91.5%), and 1.4% of respondents did not use respiratory protection anywhere. In conclusion, we consider it necessary to introduce a special module on nonspecific prevention in the discipline of hygiene.

scholarly journals Personal protective equipment for reducing the risk of COVID-19 infection among healthcare workers involved in emergency trauma surgery during the pandemic: an umbrella review protocol

BMJ Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. e045598
Author(s):  
Dylan P Griswold ◽  
Andres Gempeler ◽  
Angelos G Kolias ◽  
Peter J Hutchinson ◽  
Andres M Rubiano
Keyword(s):  
Health Systems ◽  
Systematic Reviews ◽  
Low Income ◽  
Personal Protective Equipment ◽  
Healthcare Workers ◽  
Evidence Synthesis ◽  
Trauma Surgery ◽  
Experimental Studies ◽  
Protective Equipment ◽  
Cochrane Central Register

IntroductionMany healthcare facilities in low-income and middle-income countries are inadequately resourced and may lack optimal organisation and governance, especially concerning surgical health systems. COVID-19 has the potential to decimate these already strained surgical healthcare services unless health systems take stringent measures to protect healthcare workers (HCWs) from viral exposure and ensure the continuity of specialised care for patients. The objective of this broad evidence synthesis is to identify and summarise the available literature regarding the efficacy of different personal protective equipment (PPE) in reducing the risk of COVID-19 infection in health personnel caring for patients undergoing trauma surgery in low-resource environments.MethodsWe will conduct several searches in the L·OVE (Living OVerview of Evidence) platform for COVID-19, a system that performs automated regular searches in PubMed, Embase, Cochrane Central Register of Controlled Trials and over 30 other sources. The search results will be presented according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram. This review will preferentially consider systematic reviews of experimental and quasi-experimental studies, as well as individual studies of such designs, evaluating the effect of different PPE on the risk of COVID-19 infection in HCWs involved in emergency trauma surgery. Critical appraisal of eligible studies for methodological quality will be conducted. Data will be extracted using the standardised data extraction tool in Covidence. Studies will, when possible, be pooled in a statistical meta-analysis using JBI SUMARI. The Grading of Recommendations, Assessment, Development and Evaluation approach for grading the certainty of evidence will be followed and a summary of findings will be created.Ethics and disseminationEthical approval is not required for this review. The plan for dissemination is to publish review findings in a peer-reviewed journal and present findings at high-level conferences that engage the most pertinent stakeholders.PROSPERO registration numberCRD42020198267.

An analytical model for predicting the shear strength of unsaturated soils

2022 ◽  
pp. 1-57
Author(s):  
Tuan A. Pham ◽  
Melis Sutman
Keyword(s):  
Shear Strength ◽  
Analytical Model ◽  
Unsaturated Soils ◽  
High Performance ◽  
Micromechanical Model ◽  
Experimental Studies ◽  
Stress Equilibrium ◽  
Proposed Model ◽  
New Equation ◽  
Multi Phase

The prediction of shear strength for unsaturated soils remains to be a significant challenge due to their complex multi-phase nature. In this paper, a review of prior experimental studies is firstly carried out to present important pieces of evidence, limitations, and some design considerations. Next, an overview of the existing shear strength equations is summarized with a brief discussion. Then, a micromechanical model with stress equilibrium conditions and multi-phase interaction considerations is presented to provide a new equation for predicting the shear strength of unsaturated soils. The validity of the proposed model is examined for several published shear strength data of different soil types. It is observed that the shear strength predicted by the analytical model is in good agreement with the experimental data, and get high performance compared to the existing models. The evaluation of the outcomes with two criteria, using average relative error and the normalized sum of squared error, proved the effectiveness and validity of the proposed equation. Using the proposed equation, the nonlinear relationship between shear strength, saturation degree, volumetric water content, and matric suction are observed.

Respiratory protection ‒ new challenges

2021 ◽  
Vol 70 (1) ◽  
pp. 129-153
Author(s):  
Władysław Harmata ◽  
Dorota Kamionek
Keyword(s):  
Air Pollution ◽  
Particulate Matter ◽  
Personal Protective Equipment ◽  
Virus Transmission ◽  
Protective Equipment ◽  
Respiratory Protection ◽  
Protection Measures ◽  
Normative Requirements ◽  
New Challenges

The paper characterizes the problem of air pollution with smog. The possibility of SARS-CoV-2 virus transmission on particulate matter and the possibility of infection was analyzed. Individual respiratory protection measures available on the market were analyzed in terms of mass use, taking into account legal and normative requirements. Keywords: personal protective equipment, respiratory protection

scholarly journals Analytical Model for Restraint Strains and Self-stressed in Expansive Concrete Filled Steel Tubes (ECFST) estimation

2020 ◽  
pp. 93-98
Author(s):  
Viktar V. Tur ◽  
Radoslaw Duda ◽  
Dina Khmaruk ◽  
Viktar Basav
Keyword(s):  
Experimental Data ◽  
Experimental Studies ◽  
Steel Tube ◽  
Development Model ◽  
Steel Tubes ◽  
Concrete Core ◽  
Expansive Concrete ◽  
Proposed Model ◽  
Comparison Results ◽  
Concrete Filled Steel Tubes

In this paper, a modified strains development model (MSDM) for expansive concrete-filled steel tube (ECFST) was formulated and verified on the experimental data, obtained from testing specimens on the expansion stage. The modified strain development model for restraint strains and self-stresses values estimation in concrete with high expansion energy capacity under any type of the symmetrical and unsymmetrical finite stiffness restraint conditions was proposed. Based on proposed MSDM a new model for expansive concrete-filled steel tubes is developed. The main difference between this model and other previously developed models consists in taking into account in the basic equations an induced force in restrain that is considered as an external load applied to the concrete core of the member. For verification of the proposed model-specific experimental studies were performed. As follows from comparison results restrained expansion strains values calculated following the proposed model shows good compliance with experimental data. The values predicted by the proposed MSDM for concrete-filled steel and obtained experimental data demonstrated good agreement that confirms the validity of the former.

scholarly journals Ensemble of Deep Capsule Neural Networks: An Application to Pneumonia Prediction

2022 ◽  
Author(s):  
Jyostna Bodapati ◽  
Rohith V N ◽  
Venkatesulu Dondeti
Keyword(s):  
Performance Measures ◽  
Laboratory Testing ◽  
Deep Neural Network ◽  
Routing Algorithm ◽  
Experimental Studies ◽  
Single Model ◽  
Appropriate Treatment ◽  
Pediatric Pneumonia ◽  
Proposed Model ◽  
Pneumonia Diagnosis

Abstract Pneumonia is the primary cause of death in children under the age of 5 years. Faster and more accurate laboratory testing aids in the prescription of appropriate treatment for children suspected of having pneumonia, lowering mortality. In this work, we implement a deep neural network model to efficiently evaluate pediatric pneumonia from chest radio graph images. Our network uses a combination of convolutional and capsule layers to capture abstract details as well as low level hidden features from the the radio graphic images, allowing the model to generate more generic predictions. Furthermore, we combine several capsule networks by stacking them together and connected them with dense layers. The joint model is trained as a single model using joint loss and the weights of the capsule layers are updated using the dynamic routing algorithm. The proposed model is evaluated using benchmark pneumonia dataset\cite{kermany2018identifying}, and the outcomes of our experimental studies indicate that the capsules employed in the network enhance the learning of disease level features that are essential in diagnosing pneumonia. According to our comparison studies, the proposed model with Convolution base from InceptionV3 attached with Capsule layers at the end surpasses several existing models by achieving an accuracy of 94.84\%. The proposed model is superior in terms of various performance measures such as accuracy and recall, and is well suited to real-time pediatric pneumonia diagnosis, substituting manual chest radiography examination.

scholarly journals Engineering modelling of structural details of a bridge

2013 ◽  
Vol 12 (2) ◽  
pp. 055-062
Author(s):  
Stefan Pradelok ◽  
Piotr Bętkowski ◽  
Adam Rudzik ◽  
Piotr Łaziński
Keyword(s):  
Computational Model ◽  
Personal Computer ◽  
Complex Structure ◽  
Railway Bridge ◽  
Local Effects ◽  
Correct Operation ◽  
Proposed Model ◽  
Short Period ◽  
Structural Details ◽  
Truss Member

This paper presents a method of engineering modelling of structural details, which enables the analysis of local static and dynamic effects in a complex structure with the use of a personal computer. An analysed structural detail, modelled with the use of shell finite elements, is mounted to a spatial truss member system. Then, on the basis of prepared computational model, a static or dynamic analysis is carried out. The proposed model allows to detect the local effects in a theoretical. Conducted analyses confirmed the correct operation of such a computational model. Hence, the method of modelling presented in this paper allows to analyse the local effects on ordinary personal computer and more importantly, the results of such calculations are available within a relatively short period of time. The calculations are carried out by analysing the local effects in a steel node of the truss railway bridge.

scholarly journals Analysis and Assessment of Hazards Caused by Chemicals Contaminating Selected Items of Firefighter Personal Protective Equipment – a Literature Review

2020 ◽  
Vol 56 (2) ◽  
pp. 92-109
Author(s):  
Sylwia Krzemińska ◽  
Małgorzata Szewczyńska
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Personal Protective Equipment ◽  
Relevant Literature ◽  
Significant Proportion ◽  
Aliphatic Hydrocarbons ◽  
Protective Equipment ◽  
Urine Metabolites ◽  
Chemical Substances ◽  
Volatile Organic

Aim: The aim of the presented paper is to review the literature concerning the risks related to possible contamination with chemical substances of firefighter’s personal protective equipment (i.e. special clothing, special gloves, firefighter boots and balaclavas) during rescue operations. The authors focused on contamination resulting from the interaction of aromatic and aliphatic hydrocarbons, volatile organic compounds and phthalates. Introduction: During rescue operations, firefighters are exposed to chemicals which are inherent in fires in buildings and open spaces. The health hazards caused by chemicals accumulating on the surface of personal protective equipment, which can enter the firefighter’s body through the skin, posing a lethal threat, is becoming an increasingly recognized issue. Scientific research shows that chemicals generated during fires are harmful – a significant proportion of them has a confirmed carcinogenic and mutagenic effect. Methodology: The presented analysis of the issue of chemical contamination of personal protective equipment and the associated risks to the firefighter was prepared on the basis of a review of selected Polish and foreign literature. The main types of chemical pollutants with chemical substances and the determined levels of pollution were addressed in the paper, indicating the conditions under which they were obtained. Additionally, the properties of the most common groups of chemicals that contaminate personal protective equipment are described. The characteristics of firefighter’s personal protective equipment, with the particular focus on the materials used for special firefighter suit, are also presented. Conclusions: A review of relevant literature indicates that contamination of firefighter’s personal protective equipment were investigated mainly with respect to the presence of aromatic and aliphatic hydrocarbons, volatile organic compounds with a proven carcinogenic effect. Phthalates as substances posing a very high risk to fertility were less commonly studied. The high content of harmful chemicals in dirt present on the surface of the material of special clothing and on other personal protective equipment, as well as in the urine metabolites, indicates unequivocally the need for decontamination of personal protective equipment after every fire.

PROBLEM OF PHYSIOLOGICAL ESTIMATION OF NEGATIVE IMPACT OF FILTERING RESPIRATORY PROTECTION DEVICES TO WORKERS

2021 ◽  
Author(s):  
V.I. Lemeshko ◽  
◽  
I.V. Ivanov ◽  
A.M. Geregey ◽  
Keyword(s):  
Human Body ◽  
Negative Impact ◽  
Protective Equipment ◽  
Respiratory Protection ◽  
Physiological Processes ◽  
Foreign Countries ◽  
Modern Methods ◽  
Physiological Assessment ◽  
Protection Devices ◽  
The Impact

Abstract: Filtering respiratory protection devices are widely used in industry and now in healthcare. The tests that these products undergo assess only the technical characteristics, without considering how the personal protective equipment affects the physiological processes of the user. The purpose of this study was to study modern methods of physiological assessment of the negative impact of the use of filtering respiratory protection devices on the human body. Analyzed domestic and foreign publications. The absence of a unified set of physiological methods for assessing the impact of filtering means of personal respiratory protection on the employee's body was established. This may be due to insufficient actualization of this problem both in Russia and in foreign countries.

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