Search results for " pressing"
showing 8 items of 38 documents
High chromium-carbon’s steel microstructural and properties evolutions after Hot Isostatic Pressing (HIP) process : From powder to final product.
2021
Fe-Cr-C alloys are frequently used as hard coating coatings for nuclear valves in pressurized water reactors (PWRs), due to their good mechanical resistance and corrosion. The Norem02 alloy (Fe - 25% Cr - 4% Ni - 4% Mn - 4% Si - 2% Mo) is one of the most promising candidates. Hardfacing coatings are typically deposited by a plasma transferred arc welding (PTAW) process, which results in a coarse and heterogeneous microstructure, exhibiting unsatisfactory wear resistance properties, mainly at high temperature. In the present study, Norem02 is developed by Hot Isostatic Compression (CIC), a pressure assisted sintering technique where a powder is placed in a plastically deformable container un…
ZnO – Yb2O3 composite optical ceramics: Synthesis, structure and spectral-luminescent properties
2022
International audience; Zinc oxide optical ceramics containing 0 – 2 wt% ytterbium are prepared byuniaxial hot pressing of commercial oxides at 1150 and 1180 °C. The ceramics have themain crystalline phase of hexagonal wurtzite-type ZnO. Ytterbium ions do not enter theZnO crystals but form a cubic sesquioxide phase of Yb2O3 located at the ZnO grainboundaries. Yb acts as an inhibitor for the ZnO grain growth. The ceramics exhibittransmittance up to 60% in the visible. Their transmission in the infrared is determinedby the free charge carrier absorption. The Yb3+ ions are found in C2 and C3i sites in Yb2O3crystals. Under X-ray excitation, the ceramics exhibit intense luminescence bands in the…
Effect of in Doping on the ZnO Powders Morphology and Microstructure Evolution of ZnO:In Ceramics as a Material for Scintillators
2018
Transparent ZnO ceramics are of interest for use as material for high-efficiency fast scintillators. Doping ZnO ceramics in order to improve complex of their properties is a promising direction. In the present research, the role of indium in the ZnO nanopowders surface interactions and in the change of microstructures and photoluminescence (PL) characteristics of sintered cera-mics is considered. Undoped and 0.13 wt% In doped ZnO ceramics are obtained by hot pressing sintering. It has been found that indium leads to the transition of initially faceted ZnO particles to rounded, contributing to good sintering with formation of diffusion active grain boundaries (GBs). Unlike ZnO ceramics, ZnO:…
Influence of the pressing system on pomegranate juice physical-chemical properties
2017
Pomegranate juice has many health properties as the fruits contain anticarcinogenic, antimicrobial and antiviral compounds. Its consumption has greatly increased throughout the world in recent years due to the potential of its different components, polyphenols and anthocyanins among all. Many studies have been performed on the pomegranate juice yield demonstrating its influence on the organoleptic and physicochemical properties of the juice. Commercial pomegranate juice production involves pressing fruits procedures. As a consequence, there is a need to investigate the pressing machine types and optimization in order to achieve juice yield and enhance its health properties. The aim of this …
Toward Sustainable PLA-Based Multilayer Complexes with Improved Barrier Properties
2019
Poly(lactic acid) or PLA is currently considered as one of the most promising substitutes of conventional plastics, with low environmental impact, especially for food packaging applications. Nevertheless, some drawbacks, such as high permeability to oxygen, are still limiting its industrial applications. The objective of this study was to highly increase the oxygen barrier performance of PLA without compromising its sustainable nature and following the principles of circular economy perspective. Coproducts coming from mill industries, such as wheat gluten proteins (WG), were used to produce PLA-WG-PLA multilayer complexes with improved barrier performance. Different technologies of industri…
Influence of the process parameters on the microstructure of a hardfacing coating elaborated by hot isostatic pressing
2019
Hot Isostatic Pressing elaboration of Norem02, an austenitic-ferritic hypereutectoid stainless steel, leads to the formation ofan austenitic matrix with a mixture of acicular M7C 3 and globular M23 C 6 carbides. The sintering tests, carried out by using an AISI304L container, showed that the final microstructure and the carbides’ distribution of the HIPed Norem02 are strongly influencedby the process parameters (heating and cooling rate, sintering time, holding temperature and pressure) and by the particles’ size,microstructure and phase distribution of the initial powder. The morphological, crystallographic and chemical analysis of the sinteredsamples were completed by comprehension of the…
Closed tank pneumatic press application to improve Sauvignon Blanc wine quality and nutraceutical properties
2019
The machines used in the winemaking process directly affect the quality of wine and its nutraceutical properties. Grapes-pressing is a very important step in winemaking as it may promote the presence and/or absence of enzymatic processes on the must, leading to the creation of different products in terms of chemical composition, starting from the same grapes. The aim of the study was to compare two different pressing systems of Sauvignon Blanc grapes using an innovative pneumatic discontinuous closed tank press in two operating modes: the traditional pressing mode in presence of oxygen and the inert pressing mode, performed through grapes pressing under inert gas with nitrogen recovery. Che…
Behind the scenes of artificial intelligence: a study of micro-work platforms in France
2019
Este artículo es una versión resumida del informe “Le Micro-travail en France. Derrière l’automatisation de nouvelles précarités au travail?» This article is a summarized version of the report "Le Micro-travail en France. Derrière l’automatisation de nouvelles précarités au travail?" .; International audience; Micro-work internet services allocate small, standardized tasks of data generation and annotation to crowds of providers. The outputs are mainly used to produce artificial intelligence solutions. It is an exemplary instance of the “platformization” of the economy, and of the transformations of labour that digital technologies bring about. To uncover the conditions under which micro-wo…