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Oxygen Flow Rate (oxygen + flow_rate)
Selected AbstractsA numerical study of combustion stability in emergency oxygen generatorsAICHE JOURNAL, Issue 4 2006Victor Diakov Abstract Combustion in sodium chlorate based emergency oxygen generators is accompanied by significant oscillations of the product oxygen flow rate, which decrease the efficiency of these devices. Reactant melting and convective heat transfer from the generated gas are key steps in the process. In this work, the effect of reactant melting on filtration combustion front propagation stability in gas generating mixtures is investigated numerically. The formation of melting regions is demonstrated in cases with significant convective gas-to-core heat transfer. Numerical simulations exhibit the oscillatory behavior of oxygen generation. By decreasing the effective heat of reaction, reactant melting is detrimental to combustion front stability. The simulations show growth of pulsations with increasing reaction activation energy and decreasing convective heat transfer. A strong stabilization of front propagation is observed when combustion temperature reaches the melting point of reaction product. These results identify the important factors responsible for pulsating behavior of chemical oxygen generators. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] COMPARISON OF SIX NON-INVASIVE SUPPLEMENTAL OXYGEN TECHNIQUES IN DOGS AND CATSJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue S1 2004MH Engelhardt Objective: To determine the amount of time required to reach the highest concentrations of oxygen at the patient's face and to determine what these highest concentrations of oxygen were with various non-invasive methods of providing supplemental oxygen using a commercial oxygen content analyzer. Procedure: Three healthy cats and 3 healthy dogs were each individually given supplemental oxygen by 6 different means, each done at 2 rates (5 L and 15 L per minute). The methods tested were: 1) Plastic sheet over conventional cage door (PSCD); 2) Blow-by where the tubing delivering the oxygen was held 8 cm from the face (BB); 3) Large plastic bag covering the patient (BAG); 4) Anesthesia induction chamber (AIC); 5) Synder oxygen cage (SOC); and 6) Crowe Oxygen E-Collar (COC). Prior to the testing, the commercial oxygen content analyzer (Mini-Ox) was calibrated. Results: Significant repeatable differences were consistently observed between the 6 methods of oxygen delivery. Results of both 5 L and 15 L/min oxygen flow rates consistently indicated that the highest oxygen concentrations were achieved with the anesthesia induction chamber and large plastic bag with oxygen concentrations reaching approximately 95% and 90%, respectively between 5 to 15 min. The BAG method had the advantage of allowing additional room for patient manipulation and the ability to place intravenous catheters while continuing to give supplemental oxygen. The plastic sheet covering a conventional cage door provided oxygen concentrations of 50% and 60% at 15 and 45 min, respectively. The Crowe Oxygen E-Collar achieved oxygen concentrations of 70% in 1.5 min. Blow-by was found to be the simplest method. It increased FiO2 to 40% within 2 min. The Synder oxygen cage was able to achieve 45% oxygen concentration within 30 min with an oxygen flow rate of 15 L/min. It was able to achieve 60% at 45 min (similar to the plastic bag on the cage). Conclusion: The order of effectiveness of providing non-invasive oxygen supplementation, from the highest to the lowest concentrations, was AIC, BAG, COC, PSCD, SOC, and BB. The fastest to the slowest increases in oxygen concentrations followed the same order at both 5 L and 15 L/min oxygen flow rate and they were BB, COC, AIC, BAG, PSCD, and SOC. SOC was the most inefficient means of providing oxygen while AIC, BAG and COC were the most efficient. [source] Deposition and Characterization of Dielectric Thin Films from Allyltrimethylsilane Glow DischargesPLASMA PROCESSES AND POLYMERS, Issue 4 2007Antonella Milella Abstract Thin films with a dielectric constant in the range of 1.9,4.5 have been deposited under different experimental conditions from allyltrimethylsilane (ATMS) and oxygen fed glow discharges. The thermal stability of the coatings is evaluated from thickness loss during the annealing process at 400 and 450,°C. Extremely low values of dielectric constant can be obtained at low input power and oxygen flow rate. However, control over the annealing temperature must be gained in order to avoid excessive film matrix collapse with subsequent deterioration of dielectric properties. For the lowest dielectric constant of 1.9, thickness shrinkage of 11% has been detected. Deposition temperature is also found to strongly affect film dielectric constant and chemical composition while input power modulation does not improve the dielectric properties of the films. [source] Catalytic Liquid Phase Oxidation of Toluene to Benzoic AcidCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2008A. Gizli Abstract The production of benzoic acid from toluene in the liquid phase with pure oxygen was studied. Investigations have been carried out with a view to determining the most suitable reaction conditions with respect to operating variables including oxygen flow rate, reaction temperature, batch time and catalyst loading. In a series of batch experiments carried out at 4,atm, the optimum values of mole ratio of oxygen to toluene, temperature, reaction time, and catalyst loading were found to be 2, 157,°C, 2,h and 0.57,g/L, respectively. In addition, a kinetic study was carried out by taking into consideration the optimum reaction conditions. The model dependent on the formation of benzyl radical was found to be feasible for describing the catalytic oxidation of toluene to benzoic acid in the liquid phase. The activation energy was determined as 40,kJ/mol. [source] Optical studies on paramagnetic/superparamagnetic ZnO:Co films grown by magnetron sputteringPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010Limei Chen Abstract A series of Zn0.9Co0.1O thin films was grown by UHV-magnetron reactive sputtering at different Ar:O2 flow rates. Decreasing the oxygen flow rates towards oxygen deficient growth lowers the structural quality of the films. Furthermore, it alters the magnetic properties of the films measured by SQUID magnetometry. Paramagnetic behaviour was observed for samples of high structural quality grown under optimized conditions whereas superparamagnetism was observed for oxygen deficient samples due to the emergence of magnetic clustering. Optical spectroscopic methods such as Raman spectroscopy, transmission and photoluminescence reveal that the altered growth conditions even affect the optical spectra of the films, and indicate that the magnetic properties are strongly associated with the structural quality of the ZnO:Co films. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||