Catalytic Active Site, Mechanistic and Kinetic Studies of Dry (CO2) Reforming of Methane over Lanthanum Zirconate (La2Zr2O7) Pyrochlores

Dry (CO2) reforming of CH4 (DRM) produces commercially important synthesis gas (H2 and CO) with H2/CO ≤ 1, which can be used for synthesis of higher alkanes and oxygenates. DRM is highly endothermic and requires temperatures as high as 800°C-1000°C to attain high equilibrium conversions. A major problem associated with DRM is catalyst deactivation due to carbon deposition. Thus it is imperative that the catalyst used for DRM must resist deactivation due to sintering and carbon deposition. DRM is well studied in the literature over various catalysts, however, there is no literature, except the Ashcroft (1993) article, for DRM over pyrochlores. Pyrochlores are metal oxides (A2B2O7), with larger rare earth metal occupying the A-site and smaller alkali earth or transition metal occupying the B-site. Ashcroft. et al. studied pyrochlore catalysts composed of rare-earth metals at A-site and catalytically active transition metals like Ru and Ir at B-site (e.g., Nd2Ru2O7, Eu2Ir2O7, and Gd2Ru2O7). These pyrochlores lost their structure under CH4 and CO2 above 340°C. Unlike their work, we use La on A-site and Zr on B-site and only partially substitute the B-site with catalytically active Rh, Ru, or Pt. This La-Zr framework provides high thermal stability to the catalysts used in our study as compared to that by Ashcroft. The inherent lattice oxygen reactivity of pyrochlores helps to resist deactivation due to carbon formation. In this work, Rh, Ru, or Pt substituted lanthanum zirconate pyrochlore catalysts were synthesized, characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The catalytic active sites and the mechanistic steps of DRM reaction were studied by means of kinetic rate modeling, isotopic labeling, in-situ Fourier transform infrared spectroscopy (FTIR), in-situ XPS and transient pulsing of CH4/CO2. The rate limiting step in the DRM mechanism over pyrochlores was determined by studying the (CH4/CD4) deuterium kinetic isotope effect. A sequence of intermediate reaction steps was proposed based on these experimental results and kinetic rate modeling, to most closely depict the mechanism of DRM over pyrochlore catalysts

A Comparative Study of Effect of Oral Melatonin Versus Oral Midazolam as Premedicant in Children Undergoing Surgery Under General Anesthesia

Background: Preoperative anxiety in children is associated with multiple post-operative outcomes like post-operative regressive behavioral disturbances, prolonged distress in the recovery phase, eating disorders, and bedwetting. The present study was designed to use low-dose oral melatonin versus oral midazolam in relieving pre-operative anxiety in children in the Indian population. Materials and Methods: A prospective randomized comparative study was conducted on children aged between 2 to 10 years of age scheduled for elective surgeries under general anesthesia are included in the study. This study was conducted with a sample size of 70. Patients were randomly distributed into two groups of 35 content. Group A (received 0.2mg/kg melatonin as premedical) and group B (received 0.5mg/kg midazolam as premedical). Results: Mean induction dose of propofol in the melatonin group was 52.143+ 18.36 mg and in the midazolam, the group was 48.714 + 16.6 mg. In our study, 90 minutes after premedication, the anxiety score was less in the midazolam group. There was no statistically significant difference between the sedation scores in melatonin and midazolam. Conclusion: Low-dose melatonin (0.2mg/kg) is not an effective alternative premedicant in children to alleviate preoperative anxiety compared to midazolam

VELOCITY : A NetFlow Based Optimized Geo-IP Lookup Tool

Title from PDF of title page, viewed on August 24, 2016Thesis advisor: Deepankar MedhiVitaIncludes bibliographical references (pages 36-38)Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2016It is a challenging task for network administrators to monitor their institution's network against undesirable behavior. While NetFlow is useful to gather flow-level data for any Internet connection, its feature is limited to traditional flow-level information such as source IP address, destination IP address, source port number, destination port number, and the protocol type. Thus, if we are to understand geographic dynamics of any flow connected to hosts at an institution from the outside world, it is not currently possible with NetFlow. To address for geo-location information of such flows, we developed the tool, VELOCITY. This tool allows to correlate IP addresses with geo-location information to visualize geo-location of incoming and outgoing flows. The VELOCITY tool consists of four different methods, with increasing order of efficiency of the methods. We found that Method 3 outperforms Methods 1 and 2 in case of filling database with geographical data for the first time. Method 4, which is an extension of Method 3, finds geographical information for IP addresses that are not present in the currently populated database, thereby providing a more optimized approach than Method 3 for incremental flow data. Furthermore, for visualization and near real time experience, we also developed a web application that displays geographical information of IP address of flows on Google maps.Introduction -- Literature survey -- Methods -- WEB application -- Results -- Conclusion -- Appendix A. Xidel -- Appendix B. GNU paralle

Thia-Michael Addition in Diverse Organic Synthesis

Thia-Michael addition reactions are significant for organic syntheses of important class of compounds to form C-S bond and its derivatives. It shows the prominent feature in medicinal field and material science. This review is focused on various methods towards thia-Michael adducts using Michael addition of sulfur containing electron rich species (Michael donor) on electron poor olefins (Michael acceptor). The C-S bond is ideal of making bioactive molecules generalized for the synthesis of various drug molecules and applied in field as insect sprays and polymer substances which are common for daily life. Due to the importance of C-S bond in recent years, novel methods for C-S bond formation were developed, which are more convenient with environment

2 D QSAR and docking of novel N-substitutedAryl amine derivatives as potential inhibitors of lumazine synthase

Fungi play a predominant role in microbial infections with serious health risk to immunocompromised individuals, including AIDS, cancer, diabetics, newborns and elderly patients. Fungi specific riboflavin metabolism involves lumazine synthase catalyzed synthesis of 6,7-dimethyl-8-D-ribityl lumazine which is converted to riboflavin by a riboflavin synthase. Therefore lumazine synthase has been targeted for design of newer antifungal agents. 32 novel N-substituted aryl amine derivatives have been designed, synthesized, characterized and screened as antifungals. Molecular modelling and docking studies with fungal lumazine synthase using the 32 inhibitors have elucidated unique binding areas within the active site of the enzyme. Amongst the selected 2-D QSAR descriptors, chiV3Cluster and Most +ve Potential show positive correlation with antifungal activity while XX Polarizability, XY Polarizability, Heat of Formation and Quadruple 3 show negative correlation with antifungal activity.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Pyrolysis-catalytic dry (CO2) reforming of waste plastics for syngas production: Influence of process parameters

Catalytic dry (CO2) reforming of waste plastics was carried out in a two stage, pyrolysis-catalytic reforming fixed bed reactor to optimise the production of syngas (H2 + CO). The effects of changing the process parameters of, catalyst preparation conditions, catalyst temperature, CO2 input rate and catalyst:plastic ratio were investigated. The plastics used was a mixture of plastics simulating that found in municipal solid waste and the catalyst used was Ni-Co-Al2O3. The results showed that changing each of the process conditions investigated, all significantly influenced syngas production. An increase of 17% of syngas production was achieved from the experiment with the catalyst prepared by rising-pH technique compared to preparation via the impregnation method. The optimum syngas production of 148.6 mmolsyngas g−1swp was attained at the catalytic dry reforming temperature of 800 °C and catalyst:plastic ratio of 0.5. The increase of CO2 input rate promoted a higher yield of syngas

Influence of Malnutrition on Adverse Outcome in Children with Confirmed or Probable Viral Encephalitis: A Prospective Observational Study

to explore the independent predictors of adverse outcome in the patients with confirmed/probable viral encephalitis. The primary outcome variable was the incidence of adverse outcomes defined as death or severe neurological deficit such as loss of speech, motor deficits, behavioural problems, blindness, and cognitive impairment. Patients with confirmed or probable viral encephalitis were classified into two groups based on their -score of weight-for-age as per WHO growth charts. Group I. Patients with confirmed or probable viral encephalitis with weight-for-age (W/A) -scores below −2SD were classified as undernourished. Group II. Patients with confirmed or probable viral encephalitis were classified as having normal nutritional status (weight-for-age -score >−2SD). A total of 114 patients were classified as confirmed or probable viral encephalitis based on detailed investigations. On multivariate logistic regression, undernutrition (adjusted OR: 5.05; 95% CI: 1.92 to 13.44) and requirement of ventilation (adjusted OR: 6.75; 95% CI: 3.63 to 77.34) were independent predictors of adverse outcomes in these patients. Thus, the results from our study highlight that the association between undernutrition and adverse outcome could be extended to the patients with confirmed/probable viral encephalitis

One-step reforming of CO₂ and CH₄ to high-value liquid chemicals and fuels at room temperature via plasma-driven catalysis

Conversion of CO₂ with CH₄ into liquid fuels and chemicals in a single-step catalytic process bypassing the production of syngas remains a challenge. In this study, one-step synthesis of liquid fuels and chemicals (e.g. acetic acid, methanol, ethanol and formaldehyde) from CO₂ and CH₄ has been achieved at room temperature (30°C) and atmospheric pressure for the first time using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was ca. 50-60%, with acetic acid the major component at 40.2% selectivity, the highest value reported for acetic acid so far. Interestingly, direct plasma synthesis of acetic acid from CH₄ and CO₂ is an ideal reaction with a 100% atom economy, but it is almost impossible via thermal catalysis due to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of different liquid chemicals