particulate contamination
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2022 ◽  
Author(s):  
Neha Raghava ◽  
Matthew Perkins ◽  
Graham Thomas

Abstract In light of the novel coronavirus and transmission in schools, increased scrutiny has been placed on airborne viral and particulate contamination, and efforts to mitigate this have been suggested, including the use of air purification. The importance of this is increased given the relationship between increased airborne particulates and increased coronavirus transmission, as well as the significance of removing particulates in the size range of bacteria and viruses from the air. Ambient levels of pm2.5 and pm1 in the absence of purification were recorded in two classrooms of similar size using medical grade data loggers, which then measured the change in these levels with use MedicAir air purifiers. It was found that baseline levels at times doubled the WHO limits for safe IAQ- MedicAir units were able to rapidly reduce levels of particulates to significantly below guidelines. We propose that the use of these units is an effective and rapid solution for the mitigation of coronavirus transmission, as well as the improvement of IAQ in schools.


Author(s):  
Satyam Saini ◽  
Pardeep Shahi ◽  
Pratik V Bansode ◽  
Jimil M. Shah ◽  
Dereje Agonafer

Abstract Continuous rise in cloud computing and other web-based services propelled the data center proliferation seen over the past decade. Traditional data centers use vapor-compression-based cooling units that not only reduce energy efficiency but also increase operational and initial investment costs due to involved redundancies. Free air cooling and airside economization can substantially reduce the IT Equipment (ITE) cooling power consumption, which accounts for approximately 40% of energy consumption for a typical air-cooled data center. However, this cooling approach entails an inherent risk of exposing the IT equipment to harmful ultrafine particulate contaminants, thus, potentially reducing the equipment and component reliability. The present investigation attempts to quantify the effects of particulate contamination inside the data center equipment and ITE room using CFD. An analysis of the boundary conditions to be used was done by detailed modeling of IT equipment and the data center white space. Both 2-D and 3-D simulations were done for detailed analysis of particle transport within the server enclosure. An analysis of the effect of the primary pressure loss obstructions like heat sinks and DIMMs inside the server was done to visualize the localized particle concentrations within the server. A room-level simulation was then conducted to identify the most vulnerable locations of particle concentration within the data center space. The results show that parameters such as higher velocities, heat sink cutouts, and higher aspect ratio features within the server tend to increase the particle concentration inside the servers.


2021 ◽  
Vol 2 ◽  
Author(s):  
Jennifer L. Eigenbrode ◽  
Robert Gold ◽  
John S. Canham ◽  
Erich Schulze ◽  
Alfonso F. Davila ◽  
...  

A key science priority for planetary exploration is to search for signs of life in our Solar System. Life-detection mission concepts aim to assess whether or not biomolecular signatures of life are present, which requires highly sensitive instrumentation. This introduces greater risk of false positives, and perhaps false negatives. Stringent science-derived contamination requirements for achieving science measurements on life-detection missions necessitate mitigation approaches that minimize, protect from, and prevent science-relevant contamination of critical surfaces of the science payload and provide high confidence to life-detection determinations. To this end, we report on technology advances that focus on understanding contamination transfer from pre-launch processing to end of mission using high-fidelity physics in the form of computational fluid dynamics and sorption physics for monolayer adsorption/desorption, and on developing a new full-spacecraft bio-molecular barrier design that restricts contamination of the spacecraft and instruments by the launch vehicle hardware. The bio-molecular barrier isolates the spacecraft from biological, molecular, and particulate contamination from the external environment. Models were used to evaluate contamination transport for a designs reference mission that utilizes the barrier. Results of the modeling verify the efficacy of the barrier and an in-cruise decontamination activity. Overall mission contamination tracking from launch to science operations demonstrated exceptionally low probability on contamination impacting science measurements, meeting the stringent contamination requirements of femtomolar levels of compounds. These advances will enable planetary missions that aim to detect and identify signatures of life in our Solar System.


2021 ◽  
Vol 68 (3-4) ◽  
pp. 22-28
Author(s):  
Bettina Ronai ◽  
Rainer Franz ◽  
Marcella Frauscher

Water and solid particulate contamination are the two most common contaminants of lubricated systems and may be highly problematic for these systems. To reduce downtime and prevent failure, lubricant formulations contain detergent and dispersant additives that play an important role in terms of contamination tolerance. In lack of a practical procedure for the determination of the relevant properties, a novel method for the evaluation of the dispersing ability of lubricating oils is introduced. Following and combining established lubricant analysis methods, a procedure with optimum parameters was found. An assessment of the method using fresh and artificially altered lubricating oils allowed a differentiation concerning their dispersing ability.


Author(s):  
Miranda Bradshaw ◽  
Vadim Burwitz ◽  
Gisela Hartner ◽  
Andreas Langmeier ◽  
Thomas Müller ◽  
...  

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