Search results for "Process (engineering)"
showing 10 items of 931 documents
Thermal-electrical-mechanical simulation of the nickel densification by Spark Plasma Sintering. Comparison with experiments
2016
Abstract Spark Plasma Sintering is a non-conventional process of the powder metallurgy field which uses a high electrical current to rapidly produce fully dense materials. In the present paper, a thermal-electrical-mechanical model developed on ABAQUS Software is proposed to simulate the densification of a nickel disk. A compaction model, studied in [Wolff, C., Mercier, S., Couque, H., Molinari, A., 2012. Modeling of conventional hot compaction and spark plasma sintering based on modified micromechanical models of porous materials. Mechanics of Materials 49 (0), 72–91. URL http://www.sciencedirect.com/science/article/pii/S0167663611002195 ], has been used to reproduce the densification of t…
A Simple “Plastic Bag” Technique for Visible Spectra of Solid Metal Complexes
1979
The techniques commonly used to study the visible spectra of transition metal complexes in the solid state involve diffuse reflectance from the powdered sample or transmission through a mull of the compound in mineral oil on filter paper. Pressed KBr (for anhydrous compounds) and AgCl (for compounds containing water or other highly polar ligands) disk techniques have been used even for low temperature spectra. All of the transmission techniques mentioned are based on mixing the sample with another compound which may induce changes in the compound under study via chemical reactions. Air- and water-sensitive complexes also need special care. These interferences may be reduced by the use of th…
Electrochemical conversion of CO2 to formic acid using a Sn based electrode: A critical review on the state-of-the-art technologies and their potenti…
2021
Abstract The electrochemical conversion of carbon dioxide is considered one of the most promising strategies to convert waste-CO2 into value-added chemicals. This review focuses on the synthesis of formic acid/formate in aqueous electrolyte using Sn-based cathodes; this material is considered relatively cheap and shows promising results in terms of faradaic efficiency. In order to be suitable at an industrial scale, the process should present simultaneously high current densities, faradaic efficiencies close to 100%, high concentrations of formic acid and long-term stability. Analysing the main results reported in the literature, it was observed that to date further studies are necessary to…
Air lift relevance in a side-stream MBR system
2006
Nowadays, two main MBR configurations are developed in wastewater treatment (Fig. 1a and b). The former is based on a side stream membrane module position, it is generally developed for the industrial wastewater treatment because of its compactness even if it requires more energy due to the necessity of using high suspension flow rate recycles throughout the membrane module to minimise fouling rates [1]. With this configuration the membrane maintenance is easy because of the side stream position of the membrane module relatively to the bioreactor. The second configuration is based on the immersion of membrane module directly inside the bioreactor. This configuration is more extensive becaus…
Evaluation of interfacial stress transfer efficiency by coating fragmentation test
2007
Probabilistic model of coating fragmentation under uniaxial tensile loading is developed. Analytical expressions of the crack spacing evolution are obtained for small-strain and large-strain fragmentation regimes. The model is applied for coating and interface property identification of several thin brittle coating/polymer substrate systems. An estimate of the stress transfer length, derived from the fragmentation data, is found to correlate with the interfacial shear strength thus suggesting that both parameters reflect an intrinsic property related to the mechanical efficiency of coating/substrate interface.
Creep–recovery and oscillatory rheology of flour-based systems
2023
The chapter reviews the application of creep-recovery and oscillatory rheological tests in flour based systems, including simple flour water systems, and more complex ones, such as bread, cookies and biscuits. A theoretical introduction about the fundaments and methods of linear viscoelastic rheology is presented, including general mathematical models and their application in flour based systems. A summary of experimental conditions to perform the rheological tests is covered. Functionality of flour based systems is extremely dependent on their viscoelastic properties. Processes like mixing, pumping, lamination, baking performance have been found to be strongly dependent on the system visco…
Generation and characterization of T40/A5754 interfaces with lasers
2014
Laser-induced reactive wetting and brazing of T40 titanium with A5754 aluminum alloy with 1.5 mm thickness was carried out in lap-joint configuration, with or without the use of Al5Si filler wire. A 2.4 mm diameter laser spot was positioned on the aluminum side to provoke spreading and wetting of the lower titanium sheet, with relatively low scanning speeds (0.1 to 0.6 m/min). Process conditions did not play a very significant role on mechanical strengths, which were shown to reach 250-300 N/mm on a large range of laser power and scanning speeds. In all cases considered, the fracture during tensile testing occurred next to the TiAl3 interface, but in the aluminum fusion zone. In a second st…
Preparation of cholesteric particles from cellulose derivatives in a microfluidic setup
2011
A microfluidic setup was used to process lyotropic cholesteric liquid crystalline mixtures of cellulose derivatives into spherical particles in the micrometre scale. By the method of co-flowing injection, monodisperse droplets of the liquid crystal, dispersed in an aqueous carrier fluid, were prepared. Polymerization of the acrylic solvent with UV-light fixed the orientation obtained by the flowing motion. The resulting particles were characterized by polarizing optical microscopy.
Reflection-refraction effects on light distribution inside tubular photobioreactors
2017
One of the main parameters affecting autotrophic algae cultures is photon absorption distribution inside the photobioreactor. This clearly depends on the geometry of both the radiation source and the photobioreactor, as well as on algae suspension optical properties. In this work the local volumetric rate of photon absorption LVRPA in a cross-section of a horizontal-pipe photobioreactor was investigated by means of simplified Monte Carlo simulations. In particular, the fate of a number of photons perpendicularly hitting the photobioreactor circular section was simulated in relation to different values of algae concentration. The model takes into account refraction/reflection phenomena at th…
Formulation, Characterization and Optimization of the Processing Conditions of Blends of Recycled Polyethylene and Ground Tyre Rubbers: Mechanical an…
2005
Abstract Recycling represents a valid alternative to the disposal of post-consumer plastics in common landfills if it is possible to obtain new materials with good final properties compatible with practical application and, above all, by using cheap methods. In this work the possibility to produce secondary materials by blending recycled polyethylene (RPE) coming from greenhouses and post-consumer ground tyre rubber (GTR) has been studied. In particular, the preparation of these blends has been carried out in a common industrial twin screw extruder. RPE pellets and GTR powder were fed to the extruder without any other additive. Temperature, processing speed, mixing procedure and composition…