Abrasive Flow Finishing
S Santhosh Kumar, Somashekhar S. Hiremath in Role of Surface Modification on Bacterial Adhesion of Bio-Implant Materials, 2020
Kar et al. (2009a) developed and studied the performance of five different types of polymers-based abrasive media: (a) natural rubber, (b) ethylene propylene diene monomer, (c) butyl rubber, (d) silicone rubber, and (e) styrene butadiene rubber mixed with SiC abrasive particles. Out of five media styrene butadiene, rubber-based media shows better performance in terms of viscosity, thermal stability, and finishing of work surfaces. They have conducted a study on commercial media and found a composition of 66% abrasives, 34% carrier, and other ingredients in the commercial media using thermogravimetric analysis. Kar et al. (2009b) used two different rubbers for media development – (a) natural rubber + SiC abrasive particles and (b) butyl rubber + SiC abrasive particles with naphthenic oil as processing oil. The rheological properties of the media and the effect of these media on the finishing process were studied. Based on the experiments conducted, Butyl rubber-based abrasive media had shown good performance compared to natural rubber-based media. Sankar et al. (2011) developed styrene-butadiene-based media to finish the aluminium-based metal matrix composites. They have also investigated the effect of rheological properties of abrasive media on the finishing and the obtained results are explained with respect to the media properties.
Perception, Planning, and Scoping, Problem Formulation, and Hazard Identification
Ted W. Simon in Environmental Risk Assessment, 2019
One may also measure biomarkers of effect. The most widespread use of this type of biomarker measurement is the level of liver enzymes. Pharmaceutical companies routinely use this sort of testing (see Box 2.2). However, there may be opportunities and motivation to discover chemical-specific biomarkers. For example, 1,3-butadiene, used in rubber manufacture, is metabolized to a highly reactive di-epoxide that reacts with both DNA and proteins; hemoglobin adducts have been shown to be a reliable biomarker of butadiene exposure.100–103 Chromosomal aberrations and the occurrence of mutations in specific genes in lymphocytes have been used as biomarkers of effect for 1,3-butadiene (see Box 2.2).89,100,104
Ovotoxic Environmental Chemicals: Indirect Endocrine Disruptors
Rajesh K. Naz in Endocrine Disruptors, 2004
The greater sensitivity of rats versus mice to the ovotoxicity of VCD suggested that detoxification of VCD may also play a role in species-specific sensitivity to VCH-induced ovotoxicity. It was shown that the rat had greater capacity for conversion of VCD to its inactive tetrol, as compared with the mouse, and that only rats possessed detectable ovarian VCD-hydrolytic enzymatic activity.[132] Similar results have been reported for epoxides of butadiene.[134] Therefore, the greater susceptibility of mice over rats relates to both enhanced bioactivation and reduced detoxification of the ovotoxic epoxides. Both microsomal epoxide hydrolase (mEH) and cytosolic GST, which are likely to be involved in metabolism of VCD, are expressed in the ovary.[114] Evidence that VCD is metabolized by EH has been provided in studies with rabbit liver microsomes.[135] Exposure of mice or rats to VCD caused significant depletion of hepatic glutathione levels,[136] whereas ovarian levels in rat were unaffected.[137] This may reflect glutathione conjugation to VCD through glutathione transferase activity.
Carcinogenic and health risk assessment of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene in the petrochemical industry using the US Environmental Protection Agency method
Published in International Journal of Occupational Safety and Ergonomics, 2022
Vahid Ahmadi-Moshiran, Ali Asghar Sajedian, Ahmad Soltanzadeh, Fatemeh Seifi, Rozhin Koobasi, Neda Nikbakht, Mohsen Sadeghi-Yarandi
1,3-Butadiene is a colorless gas with a mild gasoline-like odor and an odor threshold value of 0.45 ppm [7]. There is a strong association between occupational exposure to 1,3-butadiene and the occurrence of cancers of hemolymphatic organs, mainly leukemia [3,8,9]. The International Agency for Research on Cancer (IARC) has identified this chemical agent as carcinogenic to humans by inhalation and has classified 1,3-butadiene in group 1 of carcinogens [10]. In addition, previous studies have revealed that some metabolites of 1,3-butadiene are suspected of causing genetic defects [3]. Some of the hygienic effects of this compound include irritating the nervous system, eyes, nose and airways, fatigue, reducing blood pressure and ovarian atrophy [3,11,12].
Exposure to 1,3-Butadiene in the U.S. Population: National Health and Nutrition Examination Survey 2011–2016
Published in Biomarkers, 2021
Alma Nieto, Luyu Zhang, Deepak Bhandari, Wanzhe Zhu, Benjamin C. Blount, Víctor R. De Jesús
1,3-Butadiene is a volatile organic compound (VOC) with a gasoline-like odour that is primarily used as a monomer in the production of synthetic rubber (ATSDR 2012, OSHA 2012). This compound is also used in the polymer production of styrene-butadiene rubber and acrylonitrile-butadiene-styrene resin plastics (EPA 2002, ATSDR 2012). Environmental sources of 1,3-butadiene include industrial emissions; automobile exhaust; burning of wood, plastics, and rubber; cigarette smoke (ATSDR 2012); and cooking emissions (Huang et al. 2020). Additionally, 1,3-butadiene has been found in plastic containers and selected foods (Yurawecz et al. 1976, McNeal and Breder 1987, Abrantes et al. 2000). Inhalation is the main route of exposure. Exposure by ingestion is unlikely since 1,3-butadiene rapidly evaporates to the atmosphere. 1,3-Butadiene is poorly soluble in water; however, low levels are released to water and soil (EPA 2002, ATSDR 2012). In the United States, the reference concentration for breathing 1,3-butadiene in air is 0.9 ppb (EPA 2002); the legal occupational exposure limit is set to 1 ppm for an 8-h workday and a short-term exposure limit of 5 ppm for 5 minutes (OSHA 1996). Ambient 1,3-butadiene undergoes photo-initiated chemical breakdown and is expected to have a half-life of approximately 6 h (ATSDR 2012), or 2–10 h as estimated from inhalation studies in animals (Bond et al. 1987). Nonetheless, low levels of 1,3-butadiene are constantly present in urban and suburban areas due to automobile exhaust, biomass burning, or industrial emissions (Hendler et al. 2010, ATSDR 2012, Gallego et al. 2018, Xiong et al. 2020).
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