A kinetic investigation of carbon dioxide insertion processes involving anionic tungsten-alkyl and -aryl derivatives: effects of carbon dioxide pressure, counterions, and ancillary ligands. Comparisons with migratory carbon monoxide insertion processes

1985 ◽  
Vol 107 (25) ◽  
pp. 7463-7473 ◽  
Author(s):  
Donald J. Darensbourg ◽  
Rebecca Kudaroski Hanckel ◽  
Christopher G. Bauch ◽  
Magdalena Pala ◽  
Debra Simmons ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Kinetic Investigation ◽  
Ancillary Ligands ◽  
Carbon Dioxide Pressure

Exercise end-tidal carbon dioxide pressure: a new prognostic marker after acute myocardial infarction?

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
J Ferreira ◽  
P Rio ◽  
A Castelo ◽  
I Cardoso ◽  
S Silva ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Carbon Dioxide ◽  
Acute Myocardial Infarction ◽  
Prognostic Marker ◽  
Systolic Function ◽  
Prognostic Role ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Pressure ◽  
End Tidal ◽  
Maximal Effort

Abstract Funding Acknowledgements Type of funding sources: None. Background Although several cardiopulmonary exercise testing (CPET) parameters have already proved to predict prognosis, there is increasing interest in finding variables that do not require maximal effort. End-tidal carbon dioxide pressure (PETCO2), an indirect indicator of cardiac output, is one of such variables. Studies in heart failure populations already suggest its role as a prognostic factor. However, data concerning other populations are still scarce. Purpose To assess the association between exercise PETCO2, cardiac biomarkers and systolic function following acute myocardial infarction (AMI) and to evaluate its potential prognostic role in this population. Methods A retrospective single-centre analysis was conducted including patients who underwent symptom-limited CPET early after AMI. We assessed PETCO2 at baseline (PETCO2-B), at anaerobic threshold (PETCO2-AT) and at peak exercise and calculated the difference between PETCO2-AT and PETCO2-B (PETCO2-difference). We analysed their association with B-natriuretic peptide (BNP), maximal troponin after AMI as well as with left ventricular ejection fraction (LVEF) 1 year after. Results We included 40 patients with a mean age of 56 years (87.5% male), assessed with CPET a median of 3 months after AMI (80% of which were ST-elevation myocardial infarctions). Average respiratory exchange ratio was 1,1 with 48% of patients not reaching maximal effort. Mean PETCO2-AT was 37mmHg, with a mean increase from baseline of 6mmHg (PETCO2-difference). There was a significant positive correlation between all the PETCO2 variables measured and BNP values at time of AMI and on follow-up (best correlation for PETCO2-AT with BNP at AMI hospitalization, r = 0.608, p < 0.001). Maximal troponin was not correlated with PETCO2. Both PETCO2-AT and PETCO2-difference were significantly and positively correlated with LVEF 1-year post-AMI (r = 0.421, p = 0.040 and r = 0.511, p = 0.011, respectively). Conclusion PETCO2-AT and PETCO2-difference are both correlated with BNP, an established prognostic marker, and with medium-term systolic function after AMI, suggesting their potential prognostic role in this population. Further studies with larger samples are required to confirm the results of this pilot study and assess PETCO2 as a definite predictor of prognosis after AMI.

scholarly journals Controlled atmosphere GMAW welding of transportation vehicles and production machines parts made from 30MnB5 steel

2018 ◽  
Vol 216 ◽  
pp. 03001 ◽  
Author(s):  
Evgeny Ivanayskiy ◽  
Aleksei Ishkov ◽  
Aleksandr Ivanayskiy ◽  
Iakov Ochakovskii
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Chemical Composition ◽  
Controlled Atmosphere ◽  
Shielding Gas ◽  
Reducing Atmosphere ◽  
Metal Composition ◽  
Gmaw Welding ◽  
Welding Materials

The paper studies the influence of shielding gas on the composition and the structure of weld joint metal of 30MnB5 steel applied in essential parts of automobiles and tractors. The welding was performed in inert, oxidizing and reducing atmospheres. It was established that TIG welding with argon used as shielding gas did not provide the required mechanical properties when using conventional welding materials. Carbon dioxide during MAG welding caused partial burning of alloying elements. Carbon monoxide used as shielding gas was proved to form reducing atmosphere enabling to obtain chemical composition close to the base metal composition. Metallographic examinations were carried out. The obtained results provided full-strength weld, as well as the required reliability and durability of welded components and joints.

ChemInform Abstract: A Kinetic Investigation of Carbon Dioxide Insertion Processes Involving Anionic Tungsten

1986 ◽  
Vol 17 (13) ◽  
Author(s):  
D. J. DARENSBOURG ◽  
R. KUDAROSKI HANCKEL ◽  
C. G. BAUCH ◽  
M. PALA ◽  
D. SIMMONS ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Kinetic Investigation

Low-Carbon Monoxide Hydrogen by Sorption-Enhanced Reaction

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Douglas P Harrison ◽  
Zhiyong Peng
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Proton Exchange Membrane ◽  
Primary Energy ◽  
Proton Exchange ◽  
Raw Material ◽  
Impurity Level ◽  
Low Carbon ◽  
Enhanced Production

Hydrogen is an increasingly important chemical raw material and a probable future primary energy carrier. In many current and anticipated applications the carbon monoxide impurity level must be reduced to low-ppmv levels to avoid poisoning catalysts in downstream processes. Methanation is currently used to remove carbon monoxide in petroleum refining operations while preferential oxidation (PROX) is being developed for carbon monoxide control in fuel cells. Both approaches add an additional step to the multi-step hydrogen production process, and both inevitably result in hydrogen loss. The sorption enhanced process for hydrogen production, in which steam-methane reforming, water-gas shift, and carbon dioxide removal reactions occur simultaneously in the presence of a nickel-based reforming catalyst and a calcium-based carbon dioxide sorbent, is capable of producing high purity hydrogen containing minimal carbon monoxide in a single processing step. The process also has the potential for producing pure CO2 that is suitable for subsequent use or sequestration during the sorbent regeneration step. The current research on sorption-enhanced production of low-carbon monoxide hydrogen is an extension of previous research in this laboratory that proved the feasibility of producing 95+% hydrogen (dry basis), but without concern for the carbon monoxide concentration. This paper describes sorption-enhanced reaction conditions – temperature, feed gas composition, and volumetric feed rate – required to produce 95+% hydrogen containing low carbon monoxide concentrations suitable for direct use in, for example, a proton exchange membrane fuel cell.

scholarly journals The flame spectrum of carbon monoxide

1940 ◽  
Vol 176 (967) ◽  
pp. 505-521 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Electronic State ◽  
Excited Electronic State ◽  
Combustion Process ◽  
Wave Number ◽  
Band Spectrum ◽  
Liquid Form ◽  
Triangular Form ◽  
Reduced Pressure

The spectrum of the flame of carbon monoxide burning in air and in oxygen at reduced pressure has been photographed on plates of high contrast which display the band spectrum clearly above the continuous background. Greater detail has been obtained than has been recorded previously and new measurements are given. The structure of the spectrum has been studied systematically. It is shown that the bands occur in pairs with a separation of about 60 cm. -1 , this separation being due probably to the rotational structure. Various wave-number differences are found to occur frequently, and many of the strong bands are arranged in arrays using intervals of 565 and 2065 cm. -1 . The possible origin of the spectrum is discussed. The choice of emitter is limited to a polyatomic oxide of carbon, of which carbon dioxide is the most likely. The spectrum of the suboxide C 3 O 2 shows some resemblance to the flame bands, but this molecule is improbable as the emitter on other grounds. A peroxide C0 3 is also a possibility, but no evidence for the presence of this has been obtained from experiments on the slow combustion of carbon monoxide. Carbon dioxide in gaseous or liquid form is transparent through the visible and quartz ultra-violet, and the flame bands are not obtained from CO 2 in discharge tubes. Comparison with the Schumann-Runge bands of oxygen shows that it is possible that the flame bands may form part of the absorption band system of CO 2 which is known to exist below 1700 A if there is a big change in shape or size of the molecule in the two electronic states. The electronic energy levels of CO 2 are discussed. Since normal CO 2 is not built up from normal CO and oxygen, an electronic rearrangement of the CO 2 must occur after the combustion process. Mulliken has suggested that the molecule in the first excited electronic state, corresponding to absorption below 1700 A, may have a triangular form. The frequencies obtained from the flame bands are compared with the infra-red frequencies of CO 2 . The 565 interval may be identified with the transverse vibration v 2 , indicating that the excited electronic state is probably triangular in shape. The 2065 interval cannot, however, be identified with the asymmetric vibration v 3 with any certainty. If the excited electronic state of CO 2 is triangular, then molecules formed during the combustion by transitions from this level to the ground state may be “vibrationally activated”. This is probably the reason for many of the peculiarities of the combustion of carbon monoxide.

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