Reduction Rate Of Co Research Articles

Evaluating the environmental impact on connected vehicles during freeway accidents using VISSIM with probe vehicle data

<abstract> <p>We evaluated emissions as an environmental effect resulting from connected vehicles (CVs) during freeway accidents. The CVs were used to determine the CV driving characteristics, whose values were used to implement the CV driving pattern using a microscopic traffic simulation. The environmental effect of implementation of CV was evaluated using the vehicle trajectory data derived from the simulation results. Implementation of CV effectively minimized the vehicle emissions regardless of the market penetration rate (MPR). In terms of vehicle type, the emissions reduction rate of passenger cars was the highest at a maximum of 33.4%. In the case of pollutants, the reduction rate of CO based on all vehicles was the highest at a maximum of 28.8%. Overall, we found that the implementation of CV positively affected vehicle emissions reductions, and an MPR of 60% could maximize the vehicle emissions reduction effect.</p> </abstract>

Bi2O3 induced tremella-like Bi2WO6 with visible light catalytic performance

The development of single phase photocatalyst is expected to realize clean energy and pollution treatment. Herein, we reported a novel Tremella-like Bi 2 WO 6 catalyst which was obtained by facile hydrothermal technique. The formation of Tremella-like Bi 2 WO 6 strongly depended on introduction of Bi 2 O 3 . Based on the Kirkendall effect, Bi 2 O 3 induced Bi(NO 3 ) 3 ·5H 2 O to form biscuit-like Bi 6 O 6 (OH) 3 (NO 3 ) 3 ·3H 2 O particles which provided templates and reacted simultaneously with WO 4 2− to synthesize Tremella-like Bi 2 WO 6 . The Tremella-like Bi 2 WO 6 exhibited remarkable visible-light catalytic performance. The degradation rate of RhB dye reached 100% with 10 min, the reduction rate of CO 2 was 5.5 times higher than pure Bi 2 WO 6 . Moreover, the Tremella-like Bi 2 WO 6 catalyst displayed excellent stability during the recycle experiments. The high catalytic activity makes single phase Bi 2 WO 6 catalyst great potential in environmental protection field.

Improving diesel engine performance and emissions characteristics fuelled with biodiesel

This investigation study is concerned with the effect of exhaust gas recirculation(EGR) on diesel engine performance and emission fuelled with preheated biodiesel fuel. A single cylinder, air cooled, diesel engine was used and equipped with measurement instrumentations to accomplish the purpose of investigation. This work seeks to determine the influence of EGR on engine performance characteristics and emissions. Biodiesel fuel was preheated before entering the engine through a heat exchanger. The preconditions of the engine experiments were constant in all times to ensure the accurateness of the practical results. EGR rates were changed up to 25%. Biodiesel fuel was preheated at different temperatures up to70 °C. Therefore the main goal of this investigation study can be considered that dual utility of exhaust energy to improve diesel engine performance and emissions fuelled with biodiesel. The results show a slight improvement in the performance of the engine. There is a clear reduction in pollutants emitted from engine fuelled with biodiesel, especially NOx emission, with a decrease rate of 22.2% at 25% EGR (baseline: biodiesel @ 0% EGR and 30 °C preheating), while the reduction rate of CO and HC is 8.16% and 6.13% at 0% EGR respectively.

Black single-crystal TiO2 nanosheet array films with oxygen vacancy on {001} facets for boosting photocatalytic CO2 reduction

• Preparation of black TiO 2 by a mild aluminothermic reduction. • Oxygen vacancy doping can extend the light absorption range of TiO 2 to the visible light region. • The black TiO 2 with oxygen vacancy on {001} facets has the best photocatalytic CO 2 reduction activity. Black TiO 2 nanosheet array films with oxygen vacancy on {001} facets were prepared by solid phase reaction with a mild aluminothermic reduction method. The oxygen vacancies increase the absorption of visible light and the separation efficiency of photogenerated electron-hole pairs. For the black TiO 2 with oxygen vacancy prepared by annealing, only the oxygen vacancies on {001} facets boost the photocatalytic CO 2 reduction, while these on {101} facets in a small number increase the recombination of photogenerated electrons and holes and inhibit the photocatalytic CO 2 reduction performance. Meanwhile, the black TiO 2 nanosheet array films with oxygen vacancy on {001} facets have a good photocatalytic CO 2 reduction to CO with a reduction rate of 128.5 µmol•g –1 •h –1 under visible light irradiation, which is ascribed to the formation of oxygen vacancy and the synergistic effect of special unsaturated coordination Ti 5c atom improving the adsorption capacity of CO 2 and increasing the reduction rate of CO 2 to CO.

REKAYASA ALAT PENYEHATAN UDARA RUANGAN UNTUK MENURUNKAN KADAR GAS KARBONMONOKSIDA (CO)

The concentration of air pollutants inside houses is greater than those outside of houses and most pollutantsconsisted of carbon monoxide (CO)-containing combustion gases that are harmful to health. It is quitenecessaryto innovate air control through engineering procedures such as room air sanitizing devices to lowerthe CO level. The purpose of the study was to determine the effectiveness of a room air-sanitizing device inreducing the levels of COgases.The study was considered as pre-experimental fashioned in a one-group pre-post test design. Theindependent variable was the room air-sanitizing device and the dependent variable was CO concentration.Data was analyzed using paired t-tests.Resultsshowed that there was a reduction in COof 185.3 ppm after passing it throuqh the room air-sanitizingdevice set at a suction flow rate of 2.2 It/min resulting in reduction of 73.9%. Paired t-tests showed a P =0.013 <0 (0.05), indicating that there was a significant difference in CO reduction after passing through thedevice. A room sanitizing device is said to be effective when the characteristics and the mass of the activatedcarbon are the same, the contact time of the adsorbate and adsorbent is sufficiently long and the rate of COreduction z 50% of the initial levels.In conclusion, there was a significant reduction in CO after passing through a room air-sanitizing device.However, the reduction could only effectively occur for less than 21 hours. It is recommended to examineother specifications of the actived carbon such as the surface area, density, porosity, and componentcomposition in order to determine factors that contribute. to the differences. Additionally, it is recommendedto engineer device with a simpler design

Research on Reduction Rate of CO and Smoke Criterion Emission in Road Tunnel Ventilation

It is known that calculating the required amount of air is the rationale of the whole design of road tunnel ventilation and defining the reduction rate of CO and smoke criterion emission also generates a great effect on the long-term required amount of air. In terms of this, through listing and analyzing the components of vehicle pollutant discharge, emission standards of pollutants from cars in the European Union (EU), and discharge standards prescribed by PIARC, it is apparent that the emission standards of vehicle pollutants in China should follow that of the EU and should be divided into 4 stages. By analyzing the annual reduction coefficient values and the criterion emission reduction of CO and smoke, with consideration of the legal provisions in China for strict limitation of CO and smoke emission from vehicles, development of automotive technology and domestic and overseas environmental requirements, it is suggested that at present the 1-2% reduction rate set according to China's Specifications for Design of Ventilation and Lighting of Highway Tunnels is conservative. Therefore, a synthetic analysis should be made in actual tunnel ventilation design and confining the required amount of air within a rational scope to ascertain the tunnel operation safety.

Electrochemical and spectroelectrochemical studies on cobalt myoglobin

The cobalt protoporphyrin-IX reconstituted myoglobin (Co-Mb) was prepared and its electrochemical and spectroelectrochemical properties were studied in comparison with native myoglobin. Unlike native myoglobin, a slow electron transfer reaction for Co(III)-Mb/Co(II)-Mb was detected by cyclic voltammogram and spectroelectrochemical methods. The chemical reduction rate of Co(III)-Mb with dithionite was also slow compared with that of native myoglobin. Direct electron transfer between Co-Mb and an In 2O 3 electrode was observed, with spectroscopic verification of different redox states of Co-Mb using an optically transparent thin layer electrode (OTTLE) cell. The reversible electrochemical redox reaction of Co(III)-Mb/Co(II)-Mb was observed using azure A, 3-amino-7-dimethylaminophenazathionium chloride, as an electron transfer mediator for the first time. The Nernst plot was obtained for Co-Mb with E 0′ of −100 mV versus Ag ∣ AgCl (sat. KCl) and n=1 at 25°C.

Substrate and cofactor reactivity of a carbon monoxide dehydrogenase-corrinoid enzyme complex: Stepwise reduction of iron-sulfur and corrinoid centers, the corrinoid cobalt(2+/1+) redox midpoint potential, and overall synthesis of acetyl-CoA

Cleavage of the acetyl carbon-carbon bond of acetyl-CoA in Methanosarcina barkeri is catalyzed by a high molecular mass multienzyme complex. The complex contains a corrinoid protein and carbon monoxide dehydrogenase and requires tetrahydrosarcinapterin (H4SPt) as methyl group acceptor. Reactions of the enzyme complex with carbon monoxide and with the methyl group donor N5-methyltetrahydrosarcinapterin (CH3-H4SPt) have been analyzed by UV-visible spectroscopy. Reduction of the enzyme complex by CO occurred in two steps. In the first step, difference spectra exhibited peaks of maximal absorbance decrease at 426 nm (major) and 324 nm (minor), characteristic of Fe-S cluster reduction. In the second step, corrinoid reduction to the Co1+ level was indicated by a prominent peak of increased absorbance at 394 nm. Spectrophotometric analyses of the corrinoid redox state were performed on the intact complex at potentials poised by equilibration with gas mixtures containing different [CO2]/[CO] ratios or by variation of the [H+]/[H2] ratio. The corrinoid Co2+/1+ midpoint potential was -426 mV (+/- 4 mV, n = 1.16 electrons, 24 degrees C), independent of pH (pH 6.4-8.0). The results indicated a significant fraction of Co1+ corrinoid at potentials existing in vivo. The reduced corrinoid reacted very rapidly with CH3-H4SPt. Reaction with methyl iodide was slow, and methylation by S-adenosylmethionine was not observed. Tne rate of methyl group transfer from CH3-H4SPt greatly exceeded the rate of CO reduction of enzyme centers. The enzyme complex catalyzed efficient synthesis of acetyl-CoA from coenzyme A, CO, and CH3-H4SPt. During acetyl-CoA synthesis, demethylation of CH3-H4SPt was monitored by the absorbance increase at 312 nm.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of specific adsorption of some simple anions at a polycrystalline silver-aqueous interface using differential capacitance and kinetic probe techniques

The specific adsorption of chloride, bromide, iodide, azide, and thiocyanate has been studied at an electropolished polycrystalline silver-aqueous interface using differential capacitance measurements. For chloride, bromide, and azide, quantitative estimates of the surface concentration of specifically adsorbed anions were obtained from capacitance-potential data in mixed fluoride electrolytes having a constant ionic strength of 0.5. The dependence of the measured capacitance upon the ionic strength of sodium fluoride was also investigated in order to check the behavior of the polycrystalline surface in comparison with the predictions of conventional double-layer models. Estimates of the specifically adsorbed charge densities of chloride, bromide, and thiocyanate anions were also obtained from a “kinetic probe” technique which entailed monitoring the response of the outer-sphere reduction rate of CO(NH 3) 5F 2+ and Co(NH 3) 6 3+ to the addition of the appropriate adsorbing anion. At the average potential of zero charge for the polycrystalline silver surface, the standard free energies of adsorption − Δ 3 o for chloride, bromide, and azide were found to be within ca. 5 kJ mol −1 of the corresponding quantities obtained at mercury electrodes. However. significantly greater increases in − Δ 3 o in the sequence Cl − < N 3 − < Br − are seen at silver compared to mercury. Electrochemical roughening in chloride media, giving silver surfaces displaying intense surface Raman scattering, yields only minor changes in the surface concentration of specifically adsorbed chloride anions.

Redox Reaction of the Central Metal Ions Coordinated to Tetra(p-sulfophenyl)porphine(TPPS). I. Photoreduction of Co(III)TPPS by Methanol and 2-Propanol

Abstract Trivalent cobalt ion coordinated to 5,10,15,20-tetra(p-sulfophenyl)porphine (TPPS) in deaerated solution was reduced to the divalent ion on illumination of light with simultaneous oxidation of alcohols. The resulting divalent ion in the porphyrin was reoxidized by admission of dioxygen or air into the solution. It was found that the metalloporphyrin played a photocatalytic role in the autoxidation of alcohols. The kinetic study on the photoreduction revealed that the reduction rate of Co(III) followed the pseudo-first-order rate expression at 20 °C and pH 6.5 to 11.5 in the presence of excess methanol or 2-propanol. The observed rate constants were dependent on [alcohol] and/or pH. Possible mechanism for the photoreduction of Co(III)TPPS in the aqueous solution was discussed in terms of preequilibrium reactions of the axial ligation of substrates to the metalloporphyrin.

Autoxidation of Aromatic Hydrocarbons Catalyzed with Cobaltic Acetate in Acetic Acid Solution. II. Oxidation of Ethylbenzene and Cumene

Abstract The oxidation of ethylbenzene and cumene catalyzed with cobaltic acetate in acetic acid was studied kinetically in order to elucidate the reaction mechanism and the roles of cobaltic salt. The maximum absorption rate of oxygen as well as the maximum reduction rate of Co(III) in the oxidation of ethylbenzene or cumene were of first order with respect to the initial concentration of hydrocarbon, of inverse first order with respect to the initial concentration of Co(II), and of second order with respect to the initial concentration of Co(III). The kinetic equations are therefore just the same as in the case of toluene, but d[Co(III)]/d[O2] gave a quite different average value of 3.8, showing that almost no regeneration of Co(III) from Co(II) due to oxidation with peroxidic compounds occurred. Both rates were remarkably accelerated by the addition of sodium acetate and also influenced by a small amount of water. The order of oxygen absorption rate in oxidation was toluene&amp;gt;ethylbenzene&amp;gt;cumene in contrast to the order of hydrogen abstraction rate by peroxy radicals. The apparent activation energy for these hydrocarbons was found to be 10.1 kcal mol−1.

Oxidation of Toluene by Cobalt(III)-Ligand Effects

Cobaltic carboxylates oxidize toluene via a reversible one electron transfer process in acetic acid solution in the absence of oxygen. Lingands of cobaltic ion were found to have a very important role in the oxidation reaction. So we investigated the effect of ligands of cobaltic io n. NeutraI Iigands affectedonIy the activity Co(III)but anion ligands affected both reaction rates and reaction products. Strongly coordinated neutral ligands such as bipyridyl, pyridine or acetonitrile reduced the reduction rate of Co(III)(Table 1, Fig.6). Large anion ligands such as iso-butyric or pelargonic anion suppressed the oxidation by the reversible one electron transfer and were favourable to decarboxylation (Table 4).Accordingly, the effect of ligands on the aromatic oxydation by Co(III)can be attributed to the steric factor rather than to the redox factor, and the rate determing step may be inner sphere complex fermation between toluene and cobaltic ion in one electron transfer process,

Oxidation of Aromatic Compounds and Olefins by Cobaltic Acetate

As various organic compounds were oxidized by cobaltic acetate in acetic acid solution in the absence of oxygen, the influence of substrate specificity on the reaction mechanism and reactivity was investigated, The reduction rate of Co(III)in the oxidation of various substrate having electrons obeyed the following equation (Figs.2, 3, 5, 6 and 7):d(C 1III) K. b, . (RHCo(M))2(C, (III))Since this equation was similar to the rate equation of the oxidation of toluene and its homologue by Co(III), various compounds would beoxidized by cobaltic acetate via reversible one electron transfer process. Kebs, was not affected by CewH bond dissociation energy of substrate but would be correlated with the ceordinatien ability of substrate to cobaltic ion and with ionization potential of substrate (Tables 1, 2 and 3).

Reduction of human ferrihemoglobin A in the presence of cysteine and the effect of carbon monoxide

The rate of reduction of human ferrihemoglobin A in the presence of cysteine is studied as a function of hemoglobin level, cysteine level, temperature, pH, ionic strength, stereospecificity, atmospheric composition and method of isolation of the hemoglobin. A mechanism for the cysteine reduction of ferrihemoglobin is suggested.CO inhibits the reduction. In the absence of other reductants ferrihemoglobin is reduced in the presence of CO alone. The rate of CO reduction is accelerated by ultraviolet light. Evidence is presented for the formation of a ferrihemoglobin-ammonia complex in aqueous solution. Extinction coefficients are given for several hemoglobin compounds at various wavelengths.