Search results for "slur"
showing 9 items of 49 documents
Particle flow modelling in slurry-fed stirred vessels
2004
In this paper experimental information on the retention time distribution (RTD) of solid particles in a high-aspect-ratio vessel, stirred by three equally spaced Rushton turbines, is presented. The relevant data were obtained by a special technique named twin system approach (TSA) that greatly simpli+es the handling of particle-laden streams and is therefore particularly suited for investigating particle RTD in 9ow systems. The technique fundamentals are +rst summarized, together with the data analysis procedure. This lastly requires a numerical deconvolution operation that is easily performed with the help of Z-transforms. Two di;erent approaches for excluding the spurious contributions of…
Guidelines for the assessment of the rate law of slurry photocatalytic reactions
2017
Abstract The assessment of the rate law of slurry photocatalytic reactions appears to be a hard task, mainly because in this type of reactions the average rate of reaction, which is experimentally observed in a real reactor, could be very different from the “true” (intrinsic) rate of reaction, which cannot be measured directly. In the present work, it is shown how a proper mathematical model allows the utilization of the differential and/or the integral methods of kinetic analysis. The mathematical model must take into account not only the momentum and the mass balances, but also the radiative transfer equation. However, the discrimination among different proposed kinetic laws remains diffi…
Optical properties of TiO2 suspensions: Influence of pH and powder concentration on mean particle size
2007
WOS: 000250584100025
A reaction engineering approach to kinetic analysis of photocatalytic reactions in slurry systems
2016
Abstract The knowledge of the rate equation is fundamental for the assessment of the activity of the photocatalytic material and for the study, design and optimization of photocatalytic reactors. In the case of photocatalytic reactions, the local volumetric rate of photon absorption (LVRPA) affects the reaction rate and its inherently uneven distribution within a “slurry” reactor makes complex a correct kinetic analysis. In the present work it is shown which are the critical aspects of the kinetic analysis in slurry reactors and how to carry out photocatalytic experiments to minimize the misinterpretations of the experimental results. In particular, the influence of the type of illumination…
A New Supported Zirconocene Catalyst for Ethylene Polymerization
1999
Metallocene catalysts enable the structure of polymers to be tailored in a way which has not been reached before. However, they are more active than the conventional Ziegler — Natta catalysts only as homogeneous metalocene systems, a fact that has essentially restricted their use to industrial processes producing polymers in solution. Modern polymerization processes are solvent free slurry (with liquid monomer) or gas phase processes. To use metallocene catalysts in these modern processes, it is necessary to convert them to heterogeneous catalysts [1, 2]. However, problems have appeared chiefly concerning the activity of the supported catalysts, because heterogeneous metallocene catalysts a…
Compatibility of irinotecan-loaded DC Bead with different volumes and types of non-ionic contrast media.
2015
Objectives Irinotecan-loaded microspheres are used for simultaneous embolisation and chemotherapy of liver metastases of colorectal carcinoma. The aim of the study was to evaluate the compatibility of recently introduced DC Bead M1 (bead size 70–150 µm) loaded with irinotecan after admixture with different types and volumes of non-ionic contrast media over a maximum period of 24 h and storage at room temperature. Methods Test suspensions were prepared by loading 2 mL DC Bead M1 with 100 mg irinotecan within 2 h. The loading efficiency was determined by measuring the concentrations of irinotecan in the excess solutions via a reversed phase high pressure liquid chromatography (RP-HPLC) assay …
Le parole dell'odio. Dal lessico alle pratiche verbali
2017
Argomento dell'articolo è il fenomeno dello "hate speech" (discorso d’odio). La tesi che si sostiene è che tale fenomeno può essere meglio compreso se si parte dal mettere in discussione la netta distinzione tra una tra forma di violenza puramente ‘fisica’ e una puramente ‘verbale’ e si cerca, invece, di mettere a fuoco l’intreccio tra verbalità e violenza nell’essere umano, domandandosi se, ed eventualmente in che modo, il fatto di essere" animali parlanti" modifichi anche il nostro modo di essere violenti. Per fare questo, occorre superare un approccio puramente lessicale o semantico al fenomeno e inserire invece le parole d'odio nelle concrete pratiche verbali nelle quali esse sono utili…
TRATTAMENTO DI SEDIMENTI MARINI MEDIANTE REATTORI BIOSLURRY: ANALISI DI PROCESSO E CARATTERIZZAZIONE MICROBIOLOGICA
2020
I sedimenti, elementi essenziali e dinamici di tutti i sistemi acquatici, rappresentano un potenziale serbatoio di sostanze tossiche di origine antropogenica. In ambiente marino, essi costituiscono un comparto ambientale estremamente complesso, con modalità di formazione, caratteristiche chimico-fisiche, organismi viventi e tipi di contaminazione estremamente variabili. In particolare, gli idrocarburi di origine petrolifera (indicati globalmente con la misura dei TPH - Total Petroleum Hydrocarbon) inquinanti prioritari particolarmente diffusi nelle aree fortemente industrializzate, tendono a rimanere intrappolati nei sedimenti per lunghi periodi di tempo; ciò li rende una fonte permanente d…
Packing incentives and a reliable N–H⋯N–pyridine synthon in co-crystallization of bipyridines with two agrochemical actives
2011
The co-crystallization of agrochemical actives thiophanate-methyl and thiophanate-ethyl with 2,2′-bipyridine, 4,4′-bipyridine and 1,2-bis(4-pyridyl)ethane was investigated with conventional crystallization, the slurry method and liquid-assisted grinding. Co-crystals of both thiophanates with all bipyridines were found and the structures solved with single crystal X-ray diffraction. Whereas the 2,2′-bipyridine co-crystals seem to form because of a combination of weak interactions, and in the case of the thiophanate-methyl, partly because of close packing incentives, the 4,4′-bipyridine and 1,2-bis(4-pyridyl)ethane co-crystals form mainly because of a favourable N–H···N–pyridine hydrogen bond…