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Overview of the Fermentation Industry
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
Air filter: This is a device composed of fibrous material which removes solid particulars such as dust pollen, moulds and bacteria from air. Air filters are very important in fermenters because we know that air contains a lot of particulate matter and particulate matter that are the carrier of microorganisms. If we do not take out this particulate matter from the air, then it will easily enter into the liquid media and will contaminate the system. To remove this particulate matter we use fibrous filters; in particular, glass wool fibres are largely used.
Energy Centered Maintenance (ECM)
Published in Marvin T. Howell, Energy Centered Management:, 2020
Change filters when needed—do on a schedule. Change air filters every one to three months. Air conditioners that are located next to highways or construction sites, or that are using an economizer will also need more frequent filter changes. Clean the condenser coils.
Filtration: The Underutilized IAQ Asset
Published in H.E. Burroughs, Shirley J. Hansen, Managing Indoor Air Quality, 2020
H.E. Burroughs, Shirley J. Hansen
Although the commercial building construction has largely overlooked filtration, American industry has relied heavily on clean air to enable the robust growth of technology since the World War II. Ultra high-efficiency filtration is a relatively old and well-developed technology. It has been over a half century since the development of high efficiency particulate arrestor (HEPA), as it was originally designated. More recently, the term “HEPA” is defined as a High Efficiency Particulate Air filter. The importance of this development was that it established 0.3 micron as the most penetrating particle for arrestance-type filters. This has remained as a standard for determining filter performance and has laid the groundwork for 99.97% or virtually “absolute” filtration efficiency. It also sets the fabrication pattern of deep pleated filter media as the manufacturing style of high-efficiency filters.
Testing mobile air purifiers in a school classroom: Reducing the airborne transmission risk for SARS-CoV-2
Published in Aerosol Science and Technology, 2021
J. Curtius, M. Granzin, J. Schrod
The tests were performed with commercially available mobile air purifiers (Philips Model 2887/10), which are offered as regular household appliances. The air purifiers are equipped with HEPA filters (High Efficiency Particulate Air Filter) that remove more than 99.97% of the particles in the size range of 0.1 to 0.3 µm according to the manufacturer (DOE STD 3020 2015). Note that these filters are electret filters for which the filter efficiency decreases over time (Asbach et al. 2020; Schumacher et al. 2018). The volume flow through the purifier can be adjusted in five stages: “sleep,” 1, 2, 3 and “turbo.” According to the manufacturer the CADR is at least 333 m3/h when operated in “turbo” mode and the device is designed for rooms of up to 79 m2. Note that the room size specified by the manufacturer is given with respect to the reduction of allergens and not with respect to SARS-CoV-2 reduction. Table 1 shows the measured volume flows for the higher flow regimes (stages 2, 3 or “turbo”) that were used during our tests.
Trends in onroad transportation energy and emissions
Published in Journal of the Air & Waste Management Association, 2018
Air pollutant concentrations within 300 m of major roadways have been found to be elevated compared to upwind background concentrations for numerous traffic-related air pollutants (Beckerman et al. 2008; Ginzburg et al. 2015; Hagler, Thoma, and Baldauf 2010; Jeong et al. 2015; Patton et al. 2014; Zhu et al., 2002). SOA formation has also been observed within 300 m of roadways (Stroud et al. 2014). Pollutant concentrations on the roadway are typically higher than near the roadway (e.g., Fruin et al. 2008). The concentration of traffic-related air pollutants to which vehicle occupants are exposed depends primarily on whether windows are open and, if not, on whether the vehicle ventilation system is operating with fresh air intake or recirculated air, as well as the type of pollutant (e.g., gaseous, particle size) (Fruin et al. 2008; Fujita et al. 2016; Gong, Xu, and Zhu 2009; Hudda et al. 2012; Hudda and Fruin 2018; Jiao and Frey 2013; Liu and Frey 2011; Ott, Klepeis, and Switzer 2008; Riediker et al. 2003; Zielinska et al. 2012). Cabin air filters can help reduce in-cabin exposure to particles (Muala et al. 2014; Pui et al., 2008; Yu et al. 2017). For some vehicles and pollutants, there is evidence of self-pollution from crankcase and exhaust emissions that penetrate into the cabin (Harik et al. 2017; Ireson et al. 2011; Zielinska et al. 2008).
Characterization of needle-punched nonwoven fabric air filter using computer vision – a review
Published in The Journal of The Textile Institute, 2022
Air pollution has become one of the world’s most serious environmental health threats. The latest report from the World Health Organization (WHO) showed that around 4.2 million deaths globally are because of ambient air pollution and 3.2 million deaths are due to indoor air pollution (World Health Organization, 2018, 2022). Curtis et al. (2006) research showed that indoor and outdoor air pollution exposure can cause cardiovascular diseases and respiratory infections. Research revealed that a decrease in particulate matter and contaminants causing air pollution results in the reduction and certain cases, disease prevention amongst the human population. The authors concluded that particle filtration can be a very effective method in reducing the effects of allergies and asthma (Fisk, 2013; Vijayan et al., 2015; Raju et al., 2020). The simple way to have good indoor air quality is to reduce or remove the sources of pollution and to circulate air with clean outdoor air. The air filter is a device consisting of fibrous or porous materials which remove solid particulates such as dust, bacteria, pollen, and mold from the air (Trevor & George, 2013). Air cleaners and HVAC (Heating, Ventilation, Air conditioning) filters can reduce indoor air pollution; however, frequent maintenance, like the replacement of filter media is necessary as per the surrounding atmosphere. The principal air filtration media for HAVC include nonwoven fabric since they are simpler to produce, and are versatile, especially in the range of submicron aerosols. They are doing equally well to HEPA (high-efficiency particulate air) filters or are even superior to them at smaller particle sizes (Li et al., 2014). The fabric air filter may contain fibers of different constituents like polyester or Polypropylene and varying weights. The air filtration efficiency and pressure drop the are main key parameters to judge the filtration performance. These parameters are in turn influenced by fabric structure (Hutten, 2007b). The inspection of these porous fabric filters is done by experienced workers in the industry which is a time-consuming task. This necessitates a quick evaluation of fabric structural parameters with the help of computer-based tools.