scholarly journals OPTIMISING THE DESIGN PARAMETERS OF A FILTER RESPIRATOR

2021 ◽  
Vol 37 (4) ◽  
pp. 25-34
Author(s):  
S. Cheberyachko ◽  
L. Tretiakova ◽  
Yu. Cheberyachko
Keyword(s):  
Mathematical Model ◽  
Personal Protective Equipment ◽  
Experimental Studies ◽  
Target Function ◽  
Face Mask ◽  
Tension Force ◽  
Design Parameters ◽  
Protective Equipment ◽  
Power Relationship ◽  
Force Output

Purpose. The optimum length choice of the headband insert for a dust filter respirator. Design/methodology/approach. The method of experimental planning has been applied to determine the interpolation (regression) and optimisation dependencies of the filter respirator process. The dominant variables for the respirator were selected based on experimental studies.  Input controlled variables for mathematical model are length of tape insertion and headband tension force, output parameter is volume of contaminated air suction under face mask. A regression power relationship between the variables has been established. The recall function was approximated by a second-order non-linear mathematical model. The method of least squares was applied in determining the coefficients at the control variables. Regression dependencies and additional constraints on protective and ergonomic requirements have been used in the optimisation calculations. Conclusions. The solution of the set tasks were the following results: the nonlinear mathematical model more adequately characterizes the respirator use process compared to the linear model of the first order. Relative error between experimental and calculated values of air intake does not exceed 0.6 %. The optimization task is formulated with the regression model. The target function and constraints have been defined with safety and ergonomic requirements. The target function does not have an extremum within the defined constraints. The optimum insertion length was determined graphically and was 2–3.2 cm, the headband tension force does not exceed 5 H With this parameter. Research limitations/consequences. The proposed method is universal in determining the optimum parameters for all types of personal protective equipment. Practical implications: the choice of respirator design parameters can be made using experimentation-surface fitting. Originality/value. The proposed method makes it possible to decline heuristic design methods and establish analytical relationships between the requirements and parameters of individual elements of personal protective equipment.

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.

Feasibility study: Proposed alternative to N95 respirator during the personal protective equipment shortage from COVID-19 pandemic

2021 ◽  
Vol 19 (7) ◽  
pp. 192-202
Author(s):  
Ahel El Haj Chehade, MD ◽  
Jesintha Stephenson, MD ◽  
Evan Floyd, PhD ◽  
Jean Keddissi, MD, FCCP ◽  
Tony Abdo, MD ◽  
...  
Keyword(s):  
Pulse Oximetry ◽  
Feasibility Study ◽  
Personal Protective Equipment ◽  
Geometric Mean ◽  
Face Mask ◽  
The United States ◽  
Geometric Standard Deviation ◽  
Protective Equipment ◽  
Health Administration ◽  
Fit Testing

Introduction: Having an adequate supply of personal protective equipment during the COVID-19 pandemic has been a constant challenge for hospitals across the United States. In the event of shortages, our assembled mask might offer noninferior protection compared to an N95 respirator. Objective: To study the ability of an assembled mask to pass a quantitative fit testing.Methods: We conducted a feasibility study at the Oklahoma City Veteran Affairs Health Care System. Volunteers were fitted with an assembled mask made of either a Hans Rudolph half-face mask or a Respironics Performax full-face mask, attached to an Iso-Gard HEPA light Filter 28022 through a Performax SE elbow hinge. Quantitative fit testing was conducted using the Occupation Safety and Health Administration fit testing protocol. The primary outcome was the percentage of participants who pass the quantitative fit test. Secondary outcomes included the overall fit factor (FF), average FF for different exercises, changes in pulse oximetry and endtidal CO2 at 0 and 15 minutes, willingness to use the mask, and visibility assessment.Results: Twenty participants completed the study, and all (100 percent) passed the quantitative fit testing. The overall FF had a geometric mean of 2,317 (range: 208-16,613) and a geometric standard deviation of 3.8. The lowest FF was recorded while the subjects were talking. Between time 0 and 15 minutes, there was no clinically significant change in pulse oximetry and end-tidal CO2 levels. Most participants reported “very good” visibility and were “highly likely” to use the Hans Rudolph half-face mask in the case of shortage.Conclusion: Our assembled respirator offers noninferior protection to N95 respirators in the setting of hypothetical protective equipment shortage.

Mobile Worm-Like Robots for Pipe Inspection

2015 ◽  
pp. 168-218 ◽  
Author(s):  
Sergey Fedorovich Jatsun ◽  
Andrei Vasilevich Malchikov
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Mobile Robots ◽  
Experimental Studies ◽  
Design Parameters ◽  
Robot Motion ◽  
Robot Dynamics ◽  
Confined Space ◽  
Pipe Inspection ◽  
The Mathematical Model

This chapter describes various designs of multilink mobile robots intended to move inside the confined space of pipelines. The mathematical model that describes robot dynamics and controlled motion, which allows simulating different regimes of robot motion and determining design parameters of the device and its control system, is presented. The chapter contains the results of numerical simulations for different types of worm-like mobile robots. The experimental studies of the in-pipe robots prototypes and their analyses are presented in this chapter.

Respiratory viruses on personal protective equipment and bodies of healthcare workers

2019 ◽  
Vol 40 (12) ◽  
pp. 1356-1360 ◽  
Author(s):  
Linh T. Phan ◽  
Dagmar Sweeney ◽  
Dayana Maita ◽  
Donna C. Moritz ◽  
Susan C. Bleasdale ◽  
...  
Keyword(s):  
Personal Protective Equipment ◽  
Healthcare Workers ◽  
Viral Infections ◽  
Quantitative Polymerase Chain Reaction ◽  
Face Mask ◽  
Respiratory Viruses ◽  
The Body ◽  
Protective Equipment ◽  
Bare Hand ◽  
Polymerase Chain

AbstractObjective:To characterize the magnitude of virus contamination on personal protective equipment (PPE), skin, and clothing of healthcare workers (HCWs) who cared for patients having acute viral infections.Design:Prospective observational study.Setting:Acute-care academic hospital.Participants:A total of 59 HCWs agreed to have their PPE, clothing, and/or skin swabbed for virus measurement.Methods:The PPE worn by HCW participants, including glove, face mask, gown, and personal stethoscope, were swabbed with Copan swabs. After PPE doffing, bodies and clothing of HCWs were sampled with Copan swabs: hand, face, and scrubs. Preamplification and quantitative polymerase chain reaction (qPCR) methods were used to quantify viral RNA copies in the swab samples.Results:Overall, 31% of glove samples, 21% of gown samples, and 12% of face mask samples were positive for virus. Among the body and clothing sites, 21% of bare hand samples, 11% of scrub samples, and 7% of face samples were positive for virus. Virus concentrations on PPE were not statistically significantly different than concentrations on skin and clothing under PPE. Virus concentrations on the personal stethoscopes and on the gowns were positively correlated with the number of torso contacts (P < .05). Virus concentrations on face masks were positively correlated with the number of face mask contacts and patient contacts (P < .05).Conclusions:Healthcare workers are routinely contaminated with respiratory viruses after patient care, indicating the need to ensure that HCWs complete hand hygiene and use other PPE to prevent dissemination of virus to other areas of the hospital. Modifying self-contact behaviors may decrease the presence of virus on HCWs.

scholarly journals COVID-19 Disposable Face Masks: a Precursor for Synthesis of Valuable Bioproducts

2021 ◽  
Author(s):  
Oluwatosin Oginni
Keyword(s):  
Environmental Impact ◽  
Environmental Pollution ◽  
Personal Protective Equipment ◽  
Face Mask ◽  
Protective Equipment ◽  
Thermoplastic Polymers ◽  
Secondary Transmission

Abstract Disposable face mask has become a mandatory personal protective equipment in order to prevent contracting COVID-19. With the significant surge in its usage, its adverse environmental impact is becoming a source of concern. Disposable face masks are made from thermoplastic polymers and therefore they can be safely converted into valuable bioproducts. This paper discussed the possibility of converting waste/contaminated face masks into valuable bioproducts, which will essentially eliminate secondary transmission of the coronavirus and the concerns of environmental pollution.

scholarly journals Individual-Level Heterogeneity in Mask-wearing During the COVID-19 Pandemic in Malaysia

2021 ◽  
Author(s):  
Stephen X. Zhang ◽  
Kim Hoe Looi ◽  
Nicolas Li ◽  
Jizhen LI ◽  
Xue Wan
Keyword(s):  
Health Communication ◽  
Personal Protective Equipment ◽  
Face Mask ◽  
Individual Heterogeneity ◽  
Protective Equipment ◽  
Public Places ◽  
Individual Level ◽  
The Individual ◽  
Individual Choices ◽  
Specific Health

Wearing a face mask has been a key approach to contain or slow down the spread of COVID-19 in the ongoing pandemic. However, there is huge heterogeneity among individuals in their willingness to wear face masks during an epidemic. This research aims to investigate the individual heterogeneity to wear face masks and its associated predictors during the COVID-19 pandemic when mask-wearing was not mandatory but individual choices. Based on a survey of 708 Malaysian adults and a multivariate least-squares fitting analysis, the results reveal a significant variance among individuals in wearing masks, as 34% of the individual adults did not always wear masks in public places. Female, individuals who wash their hands more frequently, and those who reported more availability of personal protective equipment were more likely to practice mask-wearing. The identification of less compliant groups of mask-wearing has critical implications by enabling more specific health communication campaigns.

A Mathematical Analysis of Directional Solidification of Aqueous Solutions

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Gideon Ukpai ◽  
Boris Rubinsky
Keyword(s):  
Mathematical Model ◽  
Aqueous Solutions ◽  
Mathematical Models ◽  
Directional Solidification ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Design Parameters ◽  
Fundamental Study ◽  
Biological Matter ◽  
Intent To Use

Abstract Horizontal directional solidification techniques have been broadly utilized for the freezing of biological matter under conditions in which the freezing rate during solidification must be controlled and known. Directional solidification is used for diverse applications such as fundamental research on freezing of biological materials, cryopreservation of biological matter, and tissue engineering. This study is motivated by our intent to use directional solidification as a simplified model for the study of three-dimensional (3D) cryoprinting. In evaluating directional solidification in the context of 3D cryoprinting, we realized that current mathematical models of directional solidification are not adequately representative for this purpose, because they are simplified and one-dimensional (1D). Here, we introduce an experimentally verified and more representative two-dimensional (2D) mathematical model of directional solidification that can aid in the fundamental study of freezing of biological matter, in particular during 3D cryoprinting. The mathematical model was used to develop correlations between the freezing rates that a layer of an aqueous solution experiences during directional solidification and the various design parameters such as thickness of the sample and temperature gradients in the substrate. Results show that the freezing rates can be higher than those suggested by the previously used simplified 1D mathematical models. The results can be used for developing simplified models of 3D cryoprinting. In addition, the results suggest that many experimental studies on directional solidification of aqueous solutions and biological matter may require readjustment of analysis, in view of these findings.

Full-face mask adapter as COVID-19 Personal Protective Equipment: design, tests and validation

2021 ◽  
Vol 19 (6) ◽  
pp. 986-993
Author(s):  
Ruben Fuentes-Alvarez ◽  
Mariel Alfaro-Ponce ◽  
Fanny Alvarado ◽  
Jessica Aidee Mora-Galvan ◽  
Rita Q. Fuentes-Aguilar ◽  
...  
Keyword(s):  
Personal Protective Equipment ◽  
Face Mask ◽  
Equipment Design ◽  
Protective Equipment ◽  
Full Face

scholarly journals Surgical Performance Is Not Negatively Impacted by Wearing a Commercial Full-Face Mask with Ad Hoc 3D-Printed Filter Connection as a Substitute for Personal Protective Equipment during the COVID-19 Pandemic: A Randomized Controlled Cross-Over Trial

2021 ◽  
Vol 10 (3) ◽  
pp. 550 ◽  
Author(s):  
Eleni Amelia Felinska ◽  
Zi-Wei Chen ◽  
Thomas Ewald Fuchs ◽  
Benjamin Otto ◽  
Hannes Götz Kenngott ◽  
...  
Keyword(s):  
Personal Protective Equipment ◽  
Ad Hoc ◽  
Face Mask ◽  
Protective Equipment ◽  
Surgical Performance ◽  
Randomized Controlled ◽  
3D Printed ◽  
Group 2 ◽  
Full Face

(1) Background: During the COVID-19 pandemic, shortages in the supply of personal protective equipment (PPE) have become apparent. The idea of using commonly available full-face diving (FFD) masks as a temporary solution was quickly spread across social media. However, it was unknown whether an FFD mask would considerably impair complex surgical tasks. Thus, we aimed to assess laparoscopic surgical performance while wearing an FFD mask as PPE. (2) Methods: In a randomized-controlled cross-over trial, 40 laparoscopically naive medical students performed laparoscopic procedures while wearing an FFD mask with ad hoc 3D-printed connections to heat and moisture exchange (HME) filters vs. wearing a common surgical face mask. The performance was evaluated using global and specific Objective Structured Assessment of Technical Skills (OSATS) checklists for suturing and cholecystectomy. (3) Results: For the laparoscopic cholecystectomy, both global OSATS scores and specific OSATS scores for the quality of procedure were similar (Group 1: 25 ± 4.3 and 45.7 ± 12.9, p = 0.485, vs. Group 2: 24.1 ± 3.7 and 43.3 ± 7.6, p = 0.485). For the laparoscopic suturing task, the FFD mask group needed similar times to the surgical mask group (3009 ± 1694 s vs. 2443 ± 949 s; p = 0.200). Some participants reported impaired verbal communication while wearing the FFD mask, as it muffled the sound of speech, as well as discomfort in breathing. (4) Conclusions: FFD masks do not affect the quality of laparoscopic surgical performance, despite being uncomfortable, and may therefore be used as a substitute for conventional PPE in times of shortage—i.e., the global COVID-19 pandemic.

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