A Study of Airborne Particles by Emission Spectrographic Method

1975 ◽  
Vol 22 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Ching-Ning Chao ◽  
Shirley Lam Lee ◽  
Hui-Tuh Tsai ◽  
Shaw-Chii Wu
Author(s):  
M. Shlepr ◽  
C. M. Vicroy

The microelectronics industry is heavily tasked with minimizing contaminates at all steps of the manufacturing process. Particles are generated by physical and/or chemical fragmentation from a mothersource. The tools and macrovolumes of chemicals used for processing, the environment surrounding the process, and the circuits themselves are all potential particle sources. A first step in eliminating these contaminants is to identify their source. Elemental analysis of the particles often proves useful toward this goal, and energy dispersive spectroscopy (EDS) is a commonly used technique. However, the large variety of source materials and process induced changes in the particles often make it difficult to discern if the particles are from a common source.Ordination is commonly used in ecology to understand community relationships. This technique usespair-wise measures of similarity. Separation of the data set is based on discrimination functions. Theend product is a spatial representation of the data with the distance between points equaling the degree of dissimilarity.


2020 ◽  
Vol 54 (6) ◽  
pp. 410-416
Author(s):  
Joyce M. Hansen ◽  
Scott Weiss ◽  
Terra A. Kremer ◽  
Myrelis Aguilar ◽  
Gerald McDonnell

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged healthcare providers in maintaining the supply of critical personal protective equipment, including single-use respirators and surgical masks. Single-use respirators and surgical masks can reduce risks from the inhalation of airborne particles and microbial contamination. The recent high-volume demand for single-use respirators and surgical masks has resulted in many healthcare facilities considering processing to address critical shortages. The dry heat process of 80°C (176°F) for two hours (120 min) has been confirmed to be an appropriate method for single-use respirator and surgical mask processing.


2004 ◽  
Vol 38 (3) ◽  
pp. 682-689 ◽  
Author(s):  
Daniel U. Pedersen ◽  
John L. Durant ◽  
Bruce W. Penman ◽  
Charles L. Crespi ◽  
Harold F. Hemond ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cyril Crawford ◽  
Emmanuel Vanoli ◽  
Baptiste Decorde ◽  
Maxime Lancelot ◽  
Camille Duprat ◽  
...  

AbstractThe COVID-19 pandemic has generated many concerns about cross-contamination risks, particularly in hospital settings and Intensive Care Units (ICU). Virus-laden aerosols produced by infected patients can propagate throughout ventilated rooms and put medical personnel entering them at risk. Experimental results found with a schlieren optical method have shown that the air flows generated by a cough and normal breathing were modified by the oxygenation technique used, especially when using High Flow Nasal Canulae, increasing the shedding of potentially infectious airborne particles. This study also uses a 3D Computational Fluid Dynamics model based on a Lattice Boltzmann Method to simulate the air flows as well as the movement of numerous airborne particles produced by a patient’s cough within an ICU room under negative pressure. The effects of different mitigation scenarii on the amount of aerosols potentially containing SARS-CoV-2 that are extracted through the ventilation system are investigated. Numerical results indicate that adequate bed orientation and additional air treatment unit positioning can increase by 40% the number of particles extracted and decrease by 25% the amount of particles deposited on surfaces 45s after shedding. This approach could help lay the grounds for a more comprehensive way to tackle contamination risks in hospitals, as the model can be seen as a proof of concept and be adapted to any room configuration.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hau D. Le ◽  
Gordon A. Novak ◽  
Kevin C. Janek ◽  
Jesse Wang ◽  
Khang N. Huynh ◽  
...  

AbstractThe coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected millions and killed more than 1.7 million people worldwide as of December 2020. Healthcare providers are at increased risk of infection when caring for patients with COVID-19. The mechanism of transmission of SARS-CoV-2 is beginning to emerge as airborne spread in addition to direct droplet and indirect contact as main routes of transmission. Here, we report on the design, construction, and testing of the BADGER (Box for Aerosol and Droplet Guarding and Evacuation in Respiratory Infection), an affordable, scalable device that contains droplets and aerosol particles, thus minimizing the risk of infection to healthcare providers. A semi-sealed environment is created inside the BADGER, which is placed over the head of the patient and maintains at least 12-air changes per hour using in-wall vacuum suction. Multiple hand-ports enable healthcare providers to perform essential tasks on a patient’s airway and head. Overall, the BADGER has the potential to contain large droplets and small airborne particles as demonstrated by simulated qualitative and quantitative assessments to provide an additional layer of protection for healthcare providers treating COVID-19 and future respiratory contagions.


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