3,618 research outputs found
Beehives in Jensen, Utah
No full textWilliam Turner was a bee keeper and had hives throughout the Jensen area. Photo can be found on page 411 of the Jensen Utah Book and on disc 64 in the RH
ROTATIONAL ANALYSIS OF LASER INDUCED FLUORESCENCE DATA FOR and O
No full textR. F. Heuff, W. J. Balfour and A. G. Adam, J. Mol. Spec. 216 136 (2002). R. H. Jensen, S. G. Fougere and W. J. Balfour, Chem. Phys. Lett. 370 106 (2003).Author Institution: Department of Chemistry, University of VictoriaWe recently reported the laser induced and dispersed spectra for rhodium monoxide. Molecular constants were derived from our rotational analysis of the four 0-0 bands of two transitions using jet-cooled high-resolution data. We have now extended the analysis to include data from 16 medium-resolution sub-bands arising from the level of the ground state. In addition, emission plates from Stockholm, recorded in the 1960s have been examined, extending the analysis to much higher J. Several bands for have also been investigated. Spectroscopic parameters from some 3000 assigned lines will be discussed
Q-subdifferential of Jensen-convex functions
No full textAbstractA real function is called radially Q-differentiable at the point x if, for every real number h, the finite limit dQf(x,h) of the ratio (f(x+rh)−f(x))/r exists whenever r tends to zero through the positive rationals. We establish that, in particular, Jensen-convex functions are everywhere radially Q-differentiable. Moreover, if f is Jensen-convex, then, for each x, the mapping h↦dQf(x,h) is subadditive, and it is an upper bound for any additive mapping A satisfying the inequality f(x)+A(y−x)⩽f(y) for every y. We also characterize all set-valued mappings built up from additive solutions A of this inequality with some Jensen-convex function f
Missed opportunities for tuberculosis diagnosis.
No full textBACKGROUND: In high tuberculosis (TB) burden, resource-poor countries, sputum smear microscopy remains the mainstay of diagnosis. The low sensitivity of this test means that patients with smear-negative but culture-positive TB pass undetected through the health care system. Such clinical episodes are missed opportunities for diagnosis and interruption of transmission, which might be averted through the application of more sensitive diagnostic tests. OBJECTIVES: To estimate the proportion of incident TB cases that might have been detected earlier than the actual date of diagnosis if a test more sensitive than smear microscopy had been used at an earlier presentation episode. METHOD: Retrospective cohort study in urban Peru, investigating health care facility interactions for symptoms suggestive of TB prior to TB diagnosis through patient interviews and a review of clinical records. RESULTS: Of 212 participants enrolled, 58% had one or more clinical interactions prior to their diagnostic episode. Of those with a prior episode, the median number of episodes was three. The median delay to diagnosis from first presentation was 26 days. CONCLUSION: There are clear missed opportunities for earlier TB diagnosis, delaying treatment initiation and continued spread of Mycobacterium tuberculosis to the community. The implementation of sensitive diagnostic tests appropriate to resource-poor settings should be given high priority
Hydrodeoxygenation of Phenol to Benzene and Cyclohexane on Rh(111) and Rh(211) Surfaces: Insights from Density Functional Theory
No full textHerein we describe the C-O cleavage of phenol and cyclohexanol over Rh (111) and Rh (211) surfaces using density functional theory calculations. Our analysis is complemented by a microkinetic model of the reactions, which indicates that the C-O bond cleavage of cyclohexanol is easier than that of phenol and that Rh (211) is more active than Rh (111) for both reactions. This indicates that phenol will react mainly following a pathway of initial hydrogenation to cyclohexanol followed by hydrodeoxygenation to cyclohexane. We show that there is a general relationship between the transition state and the final state of both C-O cleavage reactions, and that this relationship is the same for Rh (111) and Rh (211)
Unveiling the Structure Sensitivity for Direct Conversion of Syngas to C2-Oxygenates with a Multicomponent-Promoted Rh Catalyst
No full textAbstract: Mn and Li promoted Rh catalysts supported on SiO2 with a thin TiO2 layer were synthesized by stepwise incipient wetness impregnation approach. The thin TiO2 layer on the surface of SiO2 was proved to stabilize those small Rh nanoparticles and hinder their agglomeration. The reducibility of Rh on these catalysts depends on Rh particle size as well as the position of manganese oxide, and large Rh nanoparticles with MnO on Rh nanoparticles can be only reduced at an elevated temperature. Catalyst with large Rh particles exhibits a higher CO conversion and higher products selectivity towards long chain hydrocarbons and C2-oxygenates at the expense of decreasing methane formation than a similar catalyst with smaller Rh particles. This was attributed to the synergistic effect of Mn and Li promotion and molar ratio between Rh0 and Rhδ+ sites on the surface of Rh nanoparticles. Moreover, Rh nanoparticles on MnO are proved to be more efficient in promoting hydrogenation of acetaldehyde to ethanol than its counterpart with MnO on Rh nanoparticles. Finally, in order to target high C2-oxygenates selectivity, low reaction temperature together with a low H2/CO ratio in the feed is recommended. Graphic Abstract: [Figure not available: see fulltext.].ChemE/Catalysis EngineeringChemE/O&O groe
Does current policy on building energy efficiency reduce a building’s life cycle energy demand?
No full textBuilding energy efficiency regulations often focus solely on thermal energy demands. Increasing the thermal performance of the building envelope through additional insulation and efficient windows is the typical approach to increasing building thermal energy efficiency. This can result in a significant increase in embodied energy which is currently not considered in building energy regulations. A case study house in Melbourne and Brisbane, Australia is used to investigate the life cycle primary energy repercussions of increasing building energy efficiency levels over 50 years. Embodied and operational energy are quantified using the comprehensive hybrid approach and a dynamic software tool, respectively. Energy efficiency is improved by material or design changes as well as a combination of both. Results show that while increasing the envelope thermal energy performance yields thermal operational energy savings, these can be offset by the additional embodied energy required for additional insulation materials and more efficient windows. The point at which increasing the thermal performance of the envelope does not yield life cycle energy benefits is just above current minimum energy efficiency standards in Australia. In order to reduce a building’s life cycle energy demand, a more comprehensive approach that includes embodied energy and emphasises design changes is needed
Computational Exploration of Rh-III/Rh-V and Rh-III/Rh-I Catalysis in Rhodium(III)-Catalyzed C-H Activation Reactions of N-Phenoxyacetamides with Alkynes
No full textThe selective rhodium-catalyzed functionalization of arenes is greatly facilitated by oxidizing directing groups that, act both as directing groups and internal oxidants. We report density functional theory (B3LYP and M06) investigations on the mechanism of rhodium(III)-catalyzed redox coupling reaction of N-phenoxyacetamides with alkynes. The results elucidated the role of the internal oxidizing directing group, and the role of Rh-III/Rh-I and Rh-III/Rh-V catalysis of C-H functionalizations. A novel Rh-III/Rh-V-Rh-III cycle successfully rationalizes recent experimental observations by Liu and Lu et al. (Liu, G. Angew. Chem. Int. Ed. 2013, 52, 6033) on the reactions of N-phenoxyacetamides with alkynes in different solvents. Natural Bond Orbital (NBO) analysis confirms the identity of Rhy intermediate in the catalytic cycle.National Natural Science Foundation of China [21133002, 21203004]; Shenzhen Peacock Program [KQTD201103]; National Science Foundation of the USA [CHE-1361104]; National Science Foundation under the CCI Center for Selective C-H Functionalization [CHE-1205646]; National Science Foundation [OCI-1053575]SCI(E)[email protected]; [email protected]
Solvent effects in heterogeneous selective hydrogenation of acetophenone: differences between Rh/C and Rh/Al2O3 catalysts and the superiority of water as a functional solvent
No full textSelective hydrogenation of acetophenone (AP) to 1-phenylethanol (PhE) was investigated over Rh/Al2O3 and Rh/C catalysts in 13 solvents including water and conventional organic solvents. Strong solvent effects on the overall rate of AP conversion were observed in different manners depending on the catalysts used. The conversion obtained is correlated with hydrogen-bond-donation (HBD) capability for Rh/C but with hydrogen-bond-acceptance (HBA) capacity for Rh/Al2O3. The solvent effects should result from interactions between the carbonyl group of AP and the solvent molecules through hydrogen bonding for Rh/C and from those between the solvent molecules and the catalyst surface for Rh/Al2O3 having HBD hydroxyl groups on its surface. Water is the most effective functional solvent in the selective hydrogenation of AP for C and Al2O3-supported Rh catalysts due to its high HBD capability (a) and low HBA capability (beta), respectively. For the hydrogenation with Rh/Al2O3 in water, its large polarity/polarizability index (pi*) may contribute to the high selectivity to PhE
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