125,197 research outputs found
Copper catalyzed one-pot synthesis of beta-ketophosphine oxides from ketones and H-phosphine oxides
No full textA facile and efficient copper catalyzed one-pot method has been developed for the formation of beta-ketophosphine oxides from ketones and H-phosphine oxides under air at room temperature, in which vinylhydrazinedicarboxylate was formed as the key intermediate. Preliminary mechanistic studies indicated that the reaction might involve a radical process and carbonyl oxygen atom of beta-ketophosphine oxides came from molecular oxygen. (C) 2017 Elsevier Ltd. All rights reserved
Group living homes for older people with dementia: Concept and effects
No full textEefsting, J.A. [Promotor]Pot, A.M. [Promotor]Depla, M.F.I.A. [Copromotor]Lange, J. de [Copromotor
High flow ceramic pot filters
No full textCeramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6–19 L h−1), but initial LRVs for E. coli of high flow filters was slightly lower than for regular ceramic pot filters. This disadvantage was, however, only temporarily as the clogging in high flow filters had a positive effect on the LRV for E. coli (from below 1 to 2–3 after clogging). Therefore, it can be carefully concluded that regular ceramic pot filters perform better initially, but after clogging, the high flow filters have a higher flow rate as well as a higher LRV for E. coli. To improve the initial performance of new high flow filters, it is recommended to further utilize residence time of the water in the receptacle, since additional E. coli inactivation was observed during overnight storage. Although a relationship was observed between flow rate and LRV of MS2 bacteriophages, both regular and high flow filters were unable to reach over 2 LRV.Sanitary Engineerin
H- 'H POT. +' e HE- 'H POT. +' confinados via método Hartree-Fock
No full textEsse trabalho tem por objetivo estudar moléculas confinadas via método de Hartree-Fock, de modo a determinar a energia de ligação e do raio de ligação. Estudamos as moléculas de H- 'H POT. +' e HE- 'H POT. +' incluindo os efeitos de blindagem através da modificação da energia de repulsão nuclear. Essa modificação ocorreu pela introdução do fator de blindagem que, ao ser sucessivamente modificado, permitiu um estudo comparativo do comportamento da energia de ligação e do raio de ligação. A relevância desse trabalho para a área de Ciências e Tecnologia de Materiais deve-se ao fato de que a compreensão e o desenvolvimento de materiais e técnicas dependem não somente das espécies químicas, mas também das ligações químicas, pois ambas determinam as características e as propriedades do material.The main objective of this work was to study the chemical and physical properties, as the bond distance and energy, of confined atoms via Hartree-Fock method. We studied the H- 'H POT. +' e HE- 'H POT. +' molecules introducing the screening effects via modification of the nuclear repulsion energy between atoms allowing thus to understanding the effects in the bond length and energy. The relevance of this work is of prime importance in material science due to many technological applications as molecules confined to surfaces, in liquid helium, neutral plasma and catalysis. All this applications has a common background of knowledge: the influence of the material physical and chemical properties with the distance and energy between the atoms in the chemical composition of the material
H- 'H POT. +' e HE- 'H POT. +' confinados via método Hartree-Fock
No full textEsse trabalho tem por objetivo estudar moléculas confinadas via método de Hartree-Fock, de modo a determinar a energia de ligação e do raio de ligação. Estudamos as moléculas de H- 'H POT. +' e HE- 'H POT. +' incluindo os efeitos de blindagem através da modificação da energia de repulsão nuclear. Essa modificação ocorreu pela introdução do fator de blindagem que, ao ser sucessivamente modificado, permitiu um estudo comparativo do comportamento da energia de ligação e do raio de ligação. A relevância desse trabalho para a área de Ciências e Tecnologia de Materiais deve-se ao fato de que a compreensão e o desenvolvimento de materiais e técnicas dependem não somente das espécies químicas, mas também das ligações químicas, pois ambas determinam as características e as propriedades do material.The main objective of this work was to study the chemical and physical properties, as the bond distance and energy, of confined atoms via Hartree-Fock method. We studied the H- 'H POT. +' e HE- 'H POT. +' molecules introducing the screening effects via modification of the nuclear repulsion energy between atoms allowing thus to understanding the effects in the bond length and energy. The relevance of this work is of prime importance in material science due to many technological applications as molecules confined to surfaces, in liquid helium, neutral plasma and catalysis. All this applications has a common background of knowledge: the influence of the material physical and chemical properties with the distance and energy between the atoms in the chemical composition of the material
H- 'H POT. +' e HE- 'H POT. +' confinados via método Hartree-Fock
No full textEsse trabalho tem por objetivo estudar moléculas confinadas via método de Hartree-Fock, de modo a determinar a energia de ligação e do raio de ligação. Estudamos as moléculas de H- 'H POT. +' e HE- 'H POT. +' incluindo os efeitos de blindagem através da modificação da energia de repulsão nuclear. Essa modificação ocorreu pela introdução do fator de blindagem que, ao ser sucessivamente modificado, permitiu um estudo comparativo do comportamento da energia de ligação e do raio de ligação. A relevância desse trabalho para a área de Ciências e Tecnologia de Materiais deve-se ao fato de que a compreensão e o desenvolvimento de materiais e técnicas dependem não somente das espécies químicas, mas também das ligações químicas, pois ambas determinam as características e as propriedades do material.The main objective of this work was to study the chemical and physical properties, as the bond distance and energy, of confined atoms via Hartree-Fock method. We studied the H- 'H POT. +' e HE- 'H POT. +' molecules introducing the screening effects via modification of the nuclear repulsion energy between atoms allowing thus to understanding the effects in the bond length and energy. The relevance of this work is of prime importance in material science due to many technological applications as molecules confined to surfaces, in liquid helium, neutral plasma and catalysis. All this applications has a common background of knowledge: the influence of the material physical and chemical properties with the distance and energy between the atoms in the chemical composition of the material
Accessing diverse azole carboxylic acid building blocks via mild C-H carboxylation: Parallel, one-pot amide couplings and ML-guided substrate scope design
No full textThis manuscript describes a mild, functional group tolerant, and metal-free C-H carboxylation that enables direct access to azole-2-carboxylic acids, followed by amide couplings in one pot. This sequence accesses a large variety of azole-2-amides, demonstrating the significant expansion of the accessible chemical space, as compared to previously known methodologies. Key to the described reactivity is the use of silyl triflate reagents, which serve as reaction mediators in C-H deprotonation and stabilizers of (otherwise unstable) azole carboxylic acid intermediates. A diverse azole substrate scope designed via ma-chine learning-guided analysis demonstrates the broad utility of the sequence. DFT calculations provide insights into the role of silyl triflates in the reaction mechanism. Transferrable applications of the protocol are successfully established: (i) A low pressure (CO2 balloon) option for synthesizing azole-2-carboxylic acids without the need for high-pressure equipment; (ii) the use of 13CO2 for the synthesis of labeled compounds; and (iii) isocyanates as alternative electrophiles for direct C-H amidation. Fundamentally, the reported protocol expands the use of heterocycle C-H functionalization from late-stage functionalization applications towards its use in library synthesis. It provides general access to densely functionalized azole-2-carboxylic acid building blocks and demonstrates their one-pot use in diversifying amide couplings
Pepper-pot emittance measurement of laser-plasma wakefield accelerated electrons
No full textThe transverse emittance is an important parameter governing the brightness of an electron beam. Here we present the first pepper-pot measurement of the transverse emittance for a mono-energetic electron beam from a laser-plasma wakefield accelerator, carried out on the Advanced Laser-Plasma High Energy Accelerators towards X-Rays (ALPHA-X) beam line. Mono-energetic electrons are passed through an array of 52 mu m diameter holes in a tungsten mask. The pepper-pot results set an upper limit for the normalised emittance at 5.5 +/- 1 pi mm mrad for an 82 MeV beam
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Innovative Design of Gully Pot for Preventing Big Particles Clogging Problem
No full textIntroduction Gully pots or roadside catch basins are a common and important part of sewerage drainage networks. Their primary function is to retain larger solids from road runoff. They are used to minimize the problems associated with sediment in downstream drainage structures, pumps, treatment plants and receiving waters. Problem definition Gully pots clogging problems have gradually been recognized over recent years. Blockage of inflow devices (especially gully pots) is the most frequent cause of flooding, for flooding of buildings and of roads. Gully pot blockages cause the highest numbers of flood incidents and are subject to larger uncertainty than other basic events. Research After literature study, it is clear that my research focuses on large particles clogging problem. To achieve my goal, the approach could be divided in several aspects: 1. In the first place, In order to define the large particles which real clogged gully pot, a field work to interview the on-site workers from cleaning company is done. 2. Based on feedback from on-site field work, 4 kind of new alternatives are proposed. 3. Then a laboratory experiment is designed to test these alternatives and also a new re-designed gully pot provided by Wavin Company. Results 1. The new grating alternatives for original gully pot can significantly reduce the incidence of gully pot clogging problem. They can reduce the covering percentage of the grating during the extreme rain fall event and leave more opening space on the grating. 2. The new gully pot from Wavin Company has a better performance than the original gully pot. But considering the big settling tank and large grating of the new gully pot, it is not fair to directly compare with the other alternatives of original gully pot. Conclusions and recommendations The gully pot clogging problems can be improving by new alternatives design. And the results show that big size of gully pot design also will be a good choice in the future. However, the experiment results show that the new alternatives will cause a higher water level on the testing table. Also the bicycle safety on the road should be considered. For the further research, the experiment method should be improved and the maintenance cost for the new design should be a concern.Water Resources ManagementWater ManagementCivil Engineering and Geoscience
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