Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-4 (of 4 Records) |
Query Trace: DeGennaro C[original query] |
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Cryogenic air supply feasibility for a confined space: Underground refuge alternative case study
Yan L , Yantek DS , DeGennaro CR , Srednicki JR , Lambie B , Carr J . ASME J Heat Mass Transf 2024 146 (3) A breathable air source is required for a confined space such as an underground refuge alternative (RA) when it is occupied. To minimize the risk of suffocation, federal regulations require that mechanisms be provided and procedures be included so that, within the refuge alternative, the oxygen concentration is maintained at levels between 18.5% and 23% for 96 h. The regulation also requires that, during use of the RA, the concentration of carbon dioxide should not exceed 1%, and the concentration of carbon monoxide should not exceed 25 ppm. The National Institute for Occupational Safety and Health (NIOSH) evaluated the cryogenic air supply's ability to provide breathable air for a refuge alternative. A propane smoker was used to simulate human breathing by burning propane gas which will consume O(2) and generate CO(2) and H(2)O. The rate of propane burned at the smoker was controlled to represent the O(2) consumption rate for the breathing of a certain number of people. Two 96-h tests were conducted in a sealed shipping container, which was used as a surrogate for a refuge alternative. While burning propane gas to simulate human oxygen consumption, cryogenic air was provided to the shipping container to determine if the cryogenic air supply would keep the O(2) level above 18.5% and CO(2) level below 1% inside the shipping container as required by the federal regulations pertaining to refuge alternatives. Both of the 96-h tests simulated the breathing of 21 persons. The first test used the oxygen consumption rate (1.32 cu ft of pure oxygen per hour per person) specified in federal regulations, while the second test used the oxygen consumption rate specified by (Bernard et al. 2018, "Estimation of Metabolic Heat Input for Refuge Alternative Thermal Testing and Simulation," Min. Eng., 70(8), pp. 50-54) (0.67 cu ft of pure oxygen per hour per person). The test data shows that during both 96-h tests, the oxygen level was maintained within a 21-23% range, and the CO(2) level was maintained below 1% (0.2-0.45%). The information in this paper could be useful when applying a cryogenic air supply as a breathable air source for an underground refuge alternative or other confined space. [DOI: 10.1115/1.4064062]. |
Mathematical modeling for carbon dioxide level within confined spaces
Yan L , Yantek DS , DeGennaro CR , Fernando RD . ASCE ASME J Risk Uncertain Eng Syst Part B Mech Eng 2023 9 (2) Federal regulations require refuge alternatives (RAs) in underground coal mines to provide a life-sustaining environment for miners trapped underground when escape is impossible. A breathable air supply is among those requirements. For built-in-place (BIP) RAs, a borehole air supply (BAS) is commonly used to supply fresh air from the surface. Federal regulations require that such a BAS must supply fresh air at 12.5 cfm or more per person to maintain the oxygen concentration between 18.5% and 23% and carbon dioxide level below the 1% limit specified. However, it is unclear whether 12.5 cfm is indeed needed to maintain this carbon dioxide level. The minimal fresh air flow (FAF) rate needed to maintain the 1% CO2level will depend on multiple factors, including the number of people and the volume of the BIP RA. In the past, to predict the interior CO2concentration in an occupied RA, 96-h tests were performed using a physical human breathing simulator. However, given the infinite possibility of the combinations (number of people, size of the BIP RA), it would be impractical to fully investigate the range of parameters that can affect the CO2concentration using physical tests. In this paper, researchers at the National Institute for Occupational Safety and Health (NIOSH) developed a model that can predict how the %CO2in an occupied confined space changes with time given the number of occupants and the FAF rate. The model was then compared to and validated with test data. The benchmarked model can be used to predict the %CO2for any number of people and FAF rate without conducting a 96-h test. The methodology used in this model can also be used to estimate other gas levels within a confined space. © 2023 American Society of Mechanical Engineers (ASME). All rights reserved. |
Shielding material comparison for electromagnetic interference mitigation for the air pump motor of personal dust monitors
Li J , Carr J , DeGennaro C , Whisner B , McElhinney P . Min Metall Explor 2019 37 (1) 211-217 Since 2016, electromagnetic interference (EMI) of personal dust monitors (PDMs) with magnetic proximity detection systems (PDSs) has been observed in underground coal mines. The EMI causes the magnetic field measurements of a PDS to change, which, in turn, alters the calculated location of the miner relative to the machine. Any altered location calculation can potentially cause the PDS to fail to warn a worker who is at an unsafe distance from the machine, arousing a serious concern on safety hazard caused by EMI in underground mines. The search for EMI mitigation strategies led to the development and use of large shielding pouches and boxes to hold the entire PDM to reduce its magnetic emission. Research on these pouches and boxes found that although they were able to reduce the emitted radiation from the PDM, they also disturbed the magnetic field of the PDS, affecting its performance. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have focused on shielding internal PDM components rather than shielding the entire PDM. The PDM air pump motor is one of the PDM components that has been identified as a major source of electromagnetic radiation and has been selected for further study and tests. The measurements show that a small copper or aluminum foil enclosure can effectively reduce the magnetic emission of the motor by between 50 and 85% at 73 kHz. This study compares the test results of the air pump motor with various cost-effective shielding materials. The data provided in this paper can serve as a reference for shielding enclosure design of the PDM air pump motor to reduce its electromagnetic emission as one form of EMI mitigation strategy. |
Factors associated with inpatient mortality in a field hospital following the Haiti earthquake, January-May 2010
Dulski TM , Basavaraju SV , Hotz GA , Xu L , Selent MU , DeGennaro VA , Andrews D , Ford H , Coronado VG , Ginzburg E . Am J Disaster Med 2011 6 (5) 275-84 OBJECTIVE: To describe factors associated with inpatient mortality in a field hospital established following the 2010 Haiti earthquake. DESIGN: Data were abstracted from medical records of patients admitted to the University of Miami Global Institute/Project Medishare hospital. Decedents were compared to survivors in terms of age, sex, length of stay, admission ward, diagnosis, and where relevant, injury mechanism and surgical procedure. Three multivariate logistic regression models were constructed to determine predictors of death among all patients, injured patients, and noninjured patients. RESULTS: During the study period, 1,339 patients were admitted to the hospital with 100 inpatient deaths (7.5 percent). The highest proportion of deaths occurred among patients aged < or = 15 years. Among all patients, adult intensive care unit (ICU) admission (adjusted odds ratio [AOR] = 7.6 and 95% confidence interval [CI] = 3.4-16.8), neonatal ICU/pediatric ICU (NICU/PICU) admission (AOR = 7.8 and 95% CI = 2.7-22.9), and cardiac/respiratory diagnoses (AOR = 8.5 and 95% CI = 4.9-14.8) were significantly associated with death. Among injured patients, adult ICU admission (AOR = 7.4 and 95% CI = 1.7-33.3) and penetrating injury (AOR = 3.3 and 95% CI = 1.004-11.1) were significantly associated with death. Among noninjured patients, adult ICU admission (AOR = 6.6 and 95% CI = 2.7-16.4), NICU/PICU admission (AOR = 8.2 and 95% CI = 2.1-31.8), and cardiac/ respiratory diagnoses (AOR = 6.5 and 95% CI = 3.6-12.0) were significantly associated with death. CONCLUSIONS: Following earthquakes in resource-limited settings, survivors may require care in field hospitals for injuries or exacerbation of chronic medical conditions. Planning for sustained post-earthquake response should address these needs and include pediatric-specific preparation and long-term critical care requirements. |
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