This work is an experimental and theoretical analysis of factors and conditions affecting smoke and carbon monoxide (CO) production in corridor-like enclosure fires. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m x 0.5 m, door-like openings in the front panel and a propane gas burner located near the closed end. Measurements of smoke and carbon monoxide concentrations were performed at locations inside the enclosure and also in the exhaust duct of a hood collecting the combustion products. The main conclusion of this work is that smoke production depends not only on the fuel and Global Equivalence Ratio (GER) - as is reported in the literature - but also on the temperatures and residence time inside the enclosure, at least for the experimental conditions examined in this study. Additionally, it was found that the smoke concentration inside the enclosure was increasing during the ventilation controlled regime even after external burning started. Such increase was verified by temperature, smoke and velocity measurements inside the enclosure. The increase was due to reverse flow behind the flames travelling along the corridor. Namely, the gases reversed direction behind the flames with hot gases travelling in the upper layer backwards towards the closed end of the corridor in contrast to hot gas movements towards the opening in front of the flames. This recirculation was confirmed by velocity and oxygen concentration measurements in the upper and lower layers inside the enclosure. In addition, the present results show that the relationship reported in the literature between smoke and carbon monoxide production during overventilated conditions yco/ys ≈ constant, is no longer valid during an underventilated enclosure fire. The ratio yco/ys increases for the Global Equivalence Ratios of the enclosure greater than one. The obtained results are useful for CFD validation and specifically applicable for assessing smoke hazards in corridor fires in buildings where smoke concentrations can be much larger than anticipated owing to leakage to adjacent rooms behind travelling flames.

No description available.

The response of frog sciatic nerve action potentials to x-irradiation and metabolic (carbon monoxide) or transport (ouabain) inhibition was determined in an attempt to further identify the nature of radiation insult to nervous tissue. Carbon monoxide, ouabain (2 X 10-5 M), and nitrogen anoxia were shown to produce a near linear decline in action potential amplitude. The carbon monoxide and nitrogen inhibitions of activity were reversible in air; the carbon monoxide inhibition was light reversible. Ouabain inhibition was partially reversible by soaking the nerve in aerated Ringer's. Application of 120 kv x-rays (75 Kr at 4.9 Kr/min) to nerves during the linear decline in spike amplitude brought about a marked enhancement (146%) of inhibition by 99% CO/l% 02, nitrogen (136%), and ouabain (265%). All bhanges were shown to be statistically significant by a regression analysis. However, x-irradiation did not appear to alter the air reversibility of carbon monoxide and nitrogen inhibitions nor the reversibility in Ringerts of the ouabain inhibition. Additionally x-irradiation completely blocked light reversal of 98% CO/2% 02 inhibition and produced a decline in activity. A possible interpretation of these results is a compensation for radiation action at this dosage requiring metabolism and ion pump activity.

A thesis submitted in fulfilment of the requirements for the degree of Master of Science in the Faculty of science, Department of Chemistry University of the Witwatersrand Private Bag X03 Wits 2050 / In recent years, studies have shown that supported Au catalysts have high activity for CO oxidation at low or ambient temperatures. However, the activity of these catalysts is dependent on a lot of synthesis conditions as reproducibility of small sized gold particles is hard. In this study supported Au catalysts were prepared via deposition precipitation-method (DP). The small sized Au particles were supported on TiO2 (P25). The suitable synthesis conditions such as pH, aging, metal loading and catalyst pre-treatment were investigated in order to obtain optimum synthesis conditions. The catalysts were characterized with TEM, XRD, and HRTEM. It was found that 3.7 nm Au particles were best synthesized when Au metal loading is 3% at pH 8 and aged for 72 h. The suitable calcination temperature was 200 °C. It was found that the Au particle size was 4.5 nm when Au was supported on SiO2 thus making TiO2 a suitable support. Bimetallic catalyst was synthesized via DP where Pd metal was incorporated as the second metal. It was found that the type of bimetallic formed was heterostructed where both metals where separately attached on the support. The interatomic distance measured from HRTEM results confirmed that both metal were individually attached on the support. XRD results showed that there was no Au-Pd alloy phase or PdO confirming that the Pd metal on the support was indeed in metallic form. Carbon monoxide (CO) oxidation reactions were undertaken in a tubular glass flow reactor. The monometallic Au catalyst showed superior activity at 200 °C with almost 100% CO conversion. It was also observed that the activity of these catalyst decreased as temperature increased. The CO-TPD studies showed that as temperature increased there was a low CO adsorption due to a decrease in adsorption sites. Varying Pd composition in the bimetallic catalyst did not enhance catalytic activity. However, 25Au75Pd catalyst showed a better conversion as compared to other Au-Pd catalysts. Temperatures studies on bimetallic catalysts showed that as temperature increased there was a decrease in activity. The observed decrease could be attributed to catalyst formation of large particle aggregates. It was also assumed that the low activity was due to how these catalysts were prepared as there was no surfactant utilized during preparation.

The ability of pulse oximeters to measure carboxyhemoglobin (HbCO) in blood or measure accurate values of oxygen saturation (SpO2) in the presence of elevated levels of HbCO is an important advantage because high exposure to carbon monoxide (CO) can be fatal or results in permanent neurological damage. The aim of my research was to develop an algorithm that would measure SpO2 and SpCO simultaneously using a pulse oximeter. Several specific wavelengths at which changes in SpCO and SpO2 can be measured with high sensitivity and specificity were identified. The choice of these wavelengths was experimentally verified utilizing an in-vitro set up. Preliminary results using our algorithm showed an accuracy of -1.1 to +2.7% [±1.96 SD] for SpO2 ranging between 70-100%, and -2 to 3.3% [±1.96 SD] for SpCO ranging between 30% with a specificity of 83.3% and a sensitivity of 100% for SpO2 and SpCO, respectively.

Digitized by Kansas Correctional Industries

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1994. / Includes bibliographic references. Includes bibliographical references (leaves 142-146). / by Anthony James Kettle. / M.S.

Reactions of the free radical nitrogen monoxide (NO) with metal–oxygen species of metalloproteins are relevant to NO metabolism and detoxification. For example, oxyhemoglobin and oxymyoglobin react with NO to form nitrate. The ferryl state of these globins also reacts with NO to reduce them to the FeIII state, forming nitrite. This has led to the suggestion that the role of NO could be that of an antioxidant of oxoiron(IV) and oxoiron(IV) protein radicals to inhibit oxidative damage. In turn, the ferrylglobin-mediated oxidation of NO to nitrite may play a role in NO scavenging and detoxification. In the case of peroxidase enzymes, NO has been shown to increase the activity of some enzymes by accelerating reduction of compound II to the FeIII state. While synthetic examples do exist for the chemistry of superoxometal complexes and NO, knowledge of the fundamental reactivity between oxometal complexes and NO is limited. To gain insight into the reactivity of synthetic oxoiron(IV) complexes toward NO, the reaction of [FeIVO(tmc)(OAc)]+ with NO, where the Fe center is coordinated by the macrocyclic nitrogen-donor ligand 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (tmc), has been investigated. This reaction caused reduction of the FeIV center to FeII and produced nitrite, which was identified in the form of [FeII(tmc)(ONO)]+. Mechanistic studies have been conducted to distinguish between two possible pathways involving either oxygen atom or oxide(·–) ion transfer from the FeIVO group to NO. As a result of studying the reactivity of a different oxoiron(IV) complex, [FeIVO(N4Py)]2+, toward NO, the formation of FeII and nitrate was observed. Mechanistic studies have revealed a 2:1 stoichiometry between FeIV and NO. From these results, a mechanism can be proposed that includes an initial oxide(·#8211;) ion transfer from FeIVO group to NO to form nitrite, followed by an oxygen atom transfer from a second equivalent of [FeIVO(N4Py)]2+ to the nitrite intermediate to form nitrate. This second step chemistry was confirmed by independently studying the reaction of [FeIVO(N4Py)]2+ with nitrite to form nitrate. There is also a biological inorganic chemistry in which metal nitrosyl species are oxidized to form innocuous nitrite or nitrate. In this context, the oxidation of the synthetic nitrosyl complex [Fe(tmc)(NO)]2+ has been studied, which also produced [FeII(tmc)(ONO)]+. The molecular structure of [FeII(tmc)(ONO)]+ determined by X-ray crystallography indicates a bidentate binding mode of the nitrito ligand via both oxygen atoms. The oxidation results are consistent with a net oxide(·–) ion transfer mechanism forming [FeII(tmc)(NO2)]+, followed by a subsequent linkage isomerization. For comparison purposes, several related, independently synthesized [FeII(tmc)X]+ complexes (X = NO2–, NO3–, AcO–) have been characterized by spectroscopic techniques, X-ray crystallography and differential pulse and cyclic voltammetry. A final investigation involved studying the reactivity of a series of [FeIVO(tmc)X]+ (X = CF3SO3–, CF3CO2–, AcO–) complexes toward organic substrates by oxygen atom transfer and hydrogen atom abstraction to construct a reactivity trend depending on the strength of the axial ligand X.

Carbon monoxide (CO) is an extremely useful molecule with applications in industrial manufacturing, synthetic procedures as a C1 building block, and as a potential pharmaceutical to produce anti-inflammatory effects and vasodilation. However, the toxicity associated with CO has prevented its full utilization. In order to safely handle CO, compounds and molecules have been developed that act as storage materials for the gas. Ideal storage platforms only release CO upon stimulation via a trigger. Light activation is the most desirable trigger as it can be regulated in terms of the intensity and the wavelength of light used. The majority of light-induced CO-storage platforms that have been reported to date consist of metal carbonyl compounds where CO is bound directly to a metal center. However, disadvantages inherent to this motif, such as potential toxicity associated with the metal and lack of characterization of CO release remnant(s), has pushed the research community to search for alternative CO storage structures. The research presented in this dissertation outlines our approach toward the development of safe-to-handle, light-induced CO release platforms. We use a flavonol structure similar to those found in fruits and vegetables, such as quercetin, as a light-induced CO release unit. Through changes in the structure of the flavonol and its surrounding environment in chemical compounds, we have found ways to strategically control the light-induced CO release reactivity of the flavonol. Chemical compounds developed in this project are of interest for studying the effects of CO in biological systems and applications in synthetic processes.

In February 1994, EPA proposed to "refine" its carbon monoxide (CO) hot spot model, CAL3QHC, to increase its accuracy and reliability. Currently, this proposal includes using hourly meteorological data recorded at airports near the modeling sites instead of the worst case conditions now recommended as a modeling default. The analysis in this study has shown that airport data should be used only on a situational basis as discrepancies exist between airports and local intersections. It is unclear if the added meteorological data will improve CAL3QHC's performance. This study also compares actual CO concentrations and their corresponding meteorology with the worst case modeling defaults. The highest CO levels are occurring at calms (wind speed less than one meter per second) which are not able to be modeled with the current Gaussian dispersion equation in CAL3QHC. Given the findings of this analysis and the lack of other scientific evidence supporting the proposed refinements, recommendations for developing an alternative model improvement plan are outlined. / Graduation date: 1995