respirator Articles
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What manufacturers need to know about complying with OSHA’s crystalline silica regulation
While crystalline silica is a rather common mineral found naturally and used in the production of a wide range of products — from glass to ceramics — respirable crystalline silica as a byproduct of manufacturing processes represents a significant potential health risk in the workplace. Of the nearly 2.3 million U.S. workers exposed to respirable crystalline silica, many work in ...
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Evaluation of occupational exposure to aerosol emitted from die sinking electrical discharge machining process
Emission of toxic gases and aerosols is a critical occupational threat in the die sinking Electrical Discharge Machining (EDM) process. The present study is focused on the concentration of aerosols in the breathing zone of the EDM operator at various process parameters. Peak current, pulse duration, dielectric level and flushing pressure were the process parameters considered in this study, and ...
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Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge process
In order to study the minimization of excess sludge production, the reduction in the excess sludge production in the presence of an inhibitor and uncoupler was studied in this work. The experimental results show that such an addition could effectively reduce the production of excess sludge. With the energy uncoupling model established in this work, energy uncoupling coefficient (E u) was used to ...
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Using a Gas Liquid Porometer to Reliably Measure Pore Size and Distribution for Filter Media Used in Face Masks
Surgical masks and respirators are typically made of nonwoven polypropylene fabric and mostly consist of three (or more) layers. The first and third layers are generally spunbond, while the middle layer is meltblown. This composition is commonly referred to as SMS technology (Spunbond/Meltblown/Spunbond). Three layers of respirator fabric While the efficiency of face masks is measured by ...
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Influence of liquid manure on soil denitrifier abundance, denitrification, and nitrous oxide emissions
The influence of liquid dairy and swine manure, soil water-extractable C (WEC) and glucose on the amount of denitrification, the N2O molar ratio [N2O/(N2O + N2)], and the abundance of soil denitrifiers was investigated using repacked soil cores. Quantitative polymerase chain reaction was used to measure the abundance of the total bacteria (16S rRNA gene), two denitrifier guilds bearing the cnorB ...
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IRSST Studies Efficacy of N95 Respirators in Conditions Representative of Human Breathing
On June 28, 2016, Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) issued a press release announcing the availability of a study on “Efficiency Evaluation of N95 FFRs under Cyclic and Constant Flows.” Researchers tested the efficacy of N95 filtering facepiece respirators (FFR) in conditions of constant and cyclical air flow, ...
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Bridging the gap between micro - and macro-scale perspectives on the role of microbial communities in global change ecology
Abstract In order to understand the role microbial communities play in mediating ecosystem response to disturbances it is essential to address the methodological and conceptual gap that exists between micro- and macro-scale perspectives in ecology. While there is little doubt microorganisms play a central role in ecosystem functioning and therefore in ecosystem response to global ...
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The investigation of the sludge reduction efficiency and mechanisms in oxic–settling–anaerobic (OSA) process
This paper aims to provide a full understanding of the sludge reduction mechanisms in the oxic–settling–anaerobic (OSA) process and presents an evaluation of the sludge reduction efficiencies and sludge characteristics in this process compared to the conventional activated sludge process. Fifty-eight percent reduction in observed yield in the OSA process was achieved compared to the control ...
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OSHA Lowers Limit for Crystalline Silica to 50mg/m3
OSHA lowers limit for crystalline silica to 50ug/m3 READ: How the CIP 10 can lower the LOD, in determining Crystalline silica: …. the following is a lengthy discussion , but if you have concerns about STEL situations, read on:- Preamble The new rule has been published. It calls for sample collection according to the ISO respirable convention, but recognizes that the Dorr-Oliver cyclone ...
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Assessment of the endogenous respiration rate and the observed biomass yield for methanol-fed denitrifying bacteria under anoxic and aerobic conditions
In this study, the endogenous respiration rate and the observed biomass yield of denitrifying methylotrophic biomass were estimated through measuring changes in denitrification rates (DNR) as a result of maintaining the biomass under methanol deprived conditions. For this purpose, activated sludge biomass from a full-scale wastewater treatment plant was kept in 10-L batch reactors for 8 days ...
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Effect of defoliation severity on regrowth and nutritive value of perennial ryegrass dominant swards
The height or mass to which swards are defoliated can potentially affect regrowth. A field study was undertaken to determine the response of perennial ryegrass (Lolium perenne L.) dominant swards to defoliation severity over repeated defoliations during a period of low water-soluble carbohydrate (WSC) accumulation (late spring to mid-autumn due to active leaf growth and relatively high ...
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The role of homoacetogenic bacteria as efficient hydrogen scavengers in microbial electrochemical cells (MXCs)
We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen ...
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The EAWAG Bio-P module for activated sludge model No. 3
Abstract: An additional module for the prediction of enhanced biological phosphorus removal is presented on the basis of a calibrated version of ASM3. The module uses modified processes from ASM2d but neglects the fermentation of readily degradable substrate. Biomass decay is modeled in the form of endogenous respiration as in ASM3. The glycogen pool and biologically induced P-precipitation is ...
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NIOSH Announces Publication of Paper from Industrywide Study on Carbon Nanotube and Nanofiber Exposure
On April 27, 2015, the National Institute for Occupational Safety and Health (NIOSH) announced publication of “Carbon Nanotube and Nanofiber Exposure Assessments: An Analysis of 14 Site Visits” in Annals of Occupational Hygiene. The paper is the second report from NIOSH’s Industrywide Study. According to NIOSH, the findings illustrate which tasks have the highest exposures, ...
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Lichens show that fungi can acclimate their respiration to seasonal changes in temperature
Five species of lichens, the majority members of a soil-crust community (Cladonia convoluta, Diploschistes muscorum, Fulgensia fulgens, Lecanora muralis, Squamarina lentigera) showed seasonal changes of temperature sensitivity of their dark respiration (DR) to such an extent that several substantially met the definition of full acclimation, i.e. near identical DR under different nocturnal ...
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Air and nitrogen flow measurement in controlled atmosphere (CA) room
Transporting refrigerated perishable goods such as fruits and vegetables in Controlled Atmosphere (CA) is an economical solution for long distance shipments as well as long-term storage. The freshness of perishables is preserved by refrigeration and modification of the gas concentrations in CA rooms which provides reduced respiration (C6H12O6 + 6O2 à 6CO2 + 6H2O + Heat) of fruits and ...
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Iron Oxyhydroxide reduction in simulated wetland soils: Effects of mineralogical composition of Iris paints
Reducing conditions in soils can be documented by the voltage measured between Pt and reference electrodes (Eh) or by using dyes like ,-dipyridyl for identifying reduced species (such as Fe2+). Indicator of Reduction in Soils (IRIS) tubes have been recently introduced as an alternative approach for documenting reducing conditions in soils, where a synthetic Fe oxyhydroxide painted on polyvinyl ...
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Effects of heavy metal pollution on the soil microbial activity
The effects of heavy metals on soil microbial processes were investigated over a period of six weeks. Analytical grade (Sigma) sulphate salts of copper, zinc and nickel were added individually and in combinations to soil samples and incubated in different plastic pots. Samples were taken from the pots forthnightly and the rates of microbial carbon and nitrogen mineralization, microbial biomass ...
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The EAWAG Bio-P module for activated sludge model No. 3.
Abstract: An additional module for the prediction of enhanced biological phosphorus removal is presented on the basis of a calibrated version of ASM3. The module uses modified processes from ASM2d but neglects the fermentation of readily degradable substrate. Biomass decay is modeled in the form of endogenous respiration as in ASM3. Moreover, an additional glycogen pool and biologically induced ...
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Metal-responsive transcription factors that regulate iron, zinc, and copper homeostasis in eukaryotic cells
Iron, copper, and zinc are all essential nutrients. The electron transfer properties of iron and copper are fundamental to processes such as respiration and photosynthesis. Zinc forms the catalytic center in numerous enzymes and has an important structural role in a wide range of proteins. However, all these metals can be toxic if their levels and distribution are not carefully regulated, as ...
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