Longitudinal and Quadrupolar Coupling Impedance of an Elliptical Vacuum Chamber With Finite Conductivity in Terms of Mathieu Functions

The resistive wall impedance of an elliptical vacuum chamber in the classical regime with infinite thickness is known analytically for ultra-relativistic beams by means of the Yokoya form factors. Starting from the longitudinal electric field of a point charge moving at arbitrary speed in an elliptical vacuum chamber, which we express in terms of Mathieu functions, in this paper we take into account the finite conductivity of the beam pipe walls and evaluate the longitudinal and quadrupolar impedance for any beam velocity. We also obtain that the quadrupolar impedance of a circular pipe is different from zero, approaching zero only for ultra-relativistic particles. Even if some of the results, in particular in the ultrarelativistic limit, are already known and expressed in terms of form factors, this approach is the first step towards the calculation of the general problem of a multi-layer vacuum chamber with different conductivities and of elliptic cross section

biofuels and green chemistry a common journey ahead

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Catalytic Biomass Upgrading Exploiting Liquid Organic Hydrogen Carriers (LOHCs)

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:9 issue:29 pages:9604-9624 status: publishe

Heterogeneous Catalytic Approaches in C-H Activation Reactions

This review summarizes the development of user-friendly, recyclable and easily separable heterogeneous catalysts for C–H activation during the last decade until December 2015

Nucleophilic ring opening of 1,2-epoxides in aqueous medium

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C(sp³)−H Arylation Promoted by a Heterogeneous Palladium-N-Heterocyclic Carbene Complex in Batch and Continuous Flow

A heterogeneous reusable palladium(II)-bis(N-heterocyclic carbene) catalyst was prepared and shown to catalyze the intramolecular C(sp3)-H activation/cyclization of N-alkyl-2-bromoanilines furnishing indolines. This new catalytic system was based on a bis-imidazolium ligand immobilized on a spaced cross-linked polystyrene support. The iodide ligands on the catalyst played a central role in the efficiency of the process occurring through a "release and catch" mechanism. The heterogeneous nature of the catalyst was further exploited in the design of a continuous-flow protocol that allowed a more efficient recovery and reuse of the catalyst, as well as a very fast and safe procedure

Sustainable protocol for the reduction of nitroarenes by heterogeneous Au@SBA‐15 using NaBH4 under flow conditions

Gold‐incorporated SBA‐15 catalyst was prepared by a solvent‐free ball milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH using NaBH4 as reducing agent. The catalyst was reused in batch conditions over 5 consecutive runs without detecting any losses of activity and selectivity. Considering the high chemical stability and reusability of the catalytic system, a continuous flow protocol was also investigated and defined in order to minimize the production of waste associated to the process and optimize the continuous reuse of the catalyst. Benefits of flow conditions were proven by TON values that increased from 47.5 to 1902 and also by the minimization of both leaching (9.5 vs 1 ppm) and E‐factor values (8 vs 23 in batch)

Saverio Muratori e a escola Italiana de tipologia projetual

Este artigo descreve o desenvolvimento da escola Muratoriana de morfologia urbana e tipologia do edificado. Partindo do trabalho de Muratori enquanto arquiteto experiente, profundamente envolvido na interpretação Romana do racionalismo Italiano, os autores descrevem o crescente interesse de Muratori pela história como meio para recuperar o sentido de continuidade na prática arquitetónica. Adotando uma abordagem teórica assente na arquitetura e no desenho urbano, Muratori começou a trabalhar num quadro crítico que pudesse explicar a criação e a transformação da forma urbana ao longo dos séculos. Muratori teve muitos seguidores. Descreve-se o ressurgimento do interesse pelo trabalho de Muratori nos anos 90

Polymerized mixed aggregates containing gadolinium complex and CCK8 peptide.

Two novel amphiphilic unimers contg. an aliph. hydrophobic chain (PDA) with two C C triple bonds and hydrophilic heads presenting the chelating agent DTPAGlu and the CCK8 bioactive peptide, resp., have been prepd. by solid phase synthesis. Aggregates obtained by mixing together PDA-DTPAGlu, or its Gd(III) complex, and PDA-L2-CCK8 in 70/30 molar ratio before and after a polymn. process carried out by UV irradn. have been structurally characterized by means of small angle neutron scattering. The relaxivity properties of aggregates contg. Gadolinium complexes have also been investigated. Elongated mixed micelles have been obsd., in which the relaxivity value r1p for each Gadolinium complex, measured at 20 MHz and 298 K, is around 12 mM-1s-1