نتایج جستجو برای: formaldehyde threshold limit values
تعداد نتایج: 792106 فیلتر نتایج به سال:
Introduction: In hair salons, workers and customers are exposed to high concentrations of several chemical compounds used during the working environment. Volatile Organic Compounds (VOCs), particulate matter (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and formaldehyde are the major chemicals that alter the indoor air quality. This study aimed to assess the indoor...
A method to quantify sub-ppm levels of formaldehyde in acetone has been developed and it is reported here. In this method, the different reactivities and stabilities of sulfite with formaldehyde and acetone are used to separate the two carbonyl compounds. Sulfite reacts with formaldehyde to form hydroxymethanesulfonate (HMS), the non-volatile and stable nature of which allows its separation fro...
in this study, the fatigue behavior of alloy steels with different hardness values was tested. results showed that the fatigue limit increases by the increment of hardness up to 400 vickers whereas it drops when the hardness value exceeds 400 vickers. fractographic observations using scanning electron microscopy revealed non-metallic inclusions as the dominant fatigue crack initiation sites. by...
A facile, ultrasensitive, and selective sensor strip utilizing 4-amino-3-penten-2-one (fluoral-p) functionalized electrospun polyacrylonitrile (PAN) (PAN/fluoral-p) nanofibrous membranes has been successfully developed for naked-eye colorimetric assay of formaldehyde. The sensor strips presented a significant reflectance decreasing band at 417 nm which induced a vivid color change from white to...
A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L). 210 samples (41%) gave a positive purpald reaction. In th...
This paper reports the irritant effects associated with formaldehyde exposures in mobile homes. Week-long, integrated formaldehyde concentrations were measured using passive monitors in summer and winter while the mobile home residents continued their normal activities. Information on acute health problems, chronic respiratory/allergic illnesses, smoking behavior, demographic variables, and tim...
This work demonstrates a printable blending material, i.e., reduced graphene oxide (RGO) mixed with poly(methyl methacrylate) (PMMA), for formaldehyde sensing. Based on experimental results, 2% RGO/10% PMMA is an optimal ratio for formaldehyde detection, which produced a 30.5% resistance variation in response to 1000 ppm formaldehyde and high selectivity compared to different volatile organic c...
An ion imprinted polymer (IIP) based on aniline-formaldehyde was synthesized and then modified with extra aniline as cross-linker in the presence and absence of Sr (II) as the template to produce ion imprinted poly(aniline-formaldehyde) (IIPAF) and non imprinted poly(aniline-formaldehyde) (NIPAF). The sorbent was characterized by Fourier Transform Infrared Spectroscopy and was used for solid ph...
an ion imprinted polymer (iip) based on aniline-formaldehyde was synthesized and then modified with extra aniline as cross-linker in the presence and absence of sr (ii) as the template to produce ion imprinted poly(aniline-formaldehyde) (iipaf) and non imprinted poly(aniline-formaldehyde) (nipaf). the sorbent was characterized by fourier transform infrared spectroscopy and was used for solid ph...
This paper analyzes the role of threshold limit values (TLVs) in national air pollution policy during the 1980s, a period in which the Environmental Protection Agency (EPA) sought to delegate to individual states the authority to evaluate and regulate airborne toxic substances. We focus on 20 carcinogens and 11 substances with non-genotoxic health effects that were regulated by local air toxics...
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