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31.
    
In the recent situation of a historically high nickel price, austenitic stainless steels, such as 1.4301, became too expensive compared to their actual technical value in many applications. This paper presents two new stainless steel grades developed by ArcelorMittal to replace 1.4301. The first one is a 20%Cr ferritic grade. The second one is a low‐Ni Cu‐bearing austenitic grade. The choices in the compositions are described as a function of the technical requirements, economical target and the production process limitations. The final properties are discussed as a function of the composition and compared with 1.4301 and other existing stainless steels. Finally, the complementarities of these two new grades are highlighted in regard to the different application markets considered.  相似文献   
32.
    
Texture and crystallographic orientation relationships in arc-melted hypoeutectic and hypereutectic binary Nb-Si alloys are investigated. Electron backscattered diffraction (EBSD) is used here in conventional conditions, i.e., at relatively high spatial resolution (<1 μm) for ∼400×400 μm fields, as well as on very large fields (1.1×1.1 mm), at lower resolution, to get a statistical overview of the microstructure. In as-cast Nb-16Si and Nb-22Si alloys (compositions are in at. pct), [001]Nb3Si is found parallel to the local thermal gradient, with Nb3Si + Nb eutectic cells, giving rise to a microstructure similar to that obtained by directional solidification. In Nb-22Si alloy, the following orientation relationships between poles of metallic and silicide phases have been found: (111)Nb//(111)Nb3Si (as cast), (011)Nb//(011) α-Nb5Si3, and (111)Nb//(100) α-Nb5Si3 (heat treated at 1500 °C, 75 hours). This article is based on a presentation made in the symposium entitled “Beyond Nickel-Base Superalloys,” which took place March 14–18, 2004, at the TMS Spring meeting in Charlotte, NC, under the auspices of the SMD-Corrosion and Environmental Effects Committee, the SMD-High Temperature Alloys Committee, the SMD-Mechanical Behavior of Materials Committee, and the SMD-Refractory Metals Committee.  相似文献   
33.
    
For development of the French Laser Integration Line and the Laser Megajoule, we describe the design and the control of a first 383 mm x 398 mm continuous phase-plate prototype. Extensively used in laser fusion facilities for beam smoothing, this optical component was manufactured by deep etching onto a fused-silica substrate, which led to a phase plate engraved directly onto fused silica, with which good optical performance could be achieved. We demonstrate good agreement between the desired simulated component and the manufactured component in terms of focal spot shape. This demonstration was performed by both interferometric and photometric measurements.  相似文献   
34.
    
ABSTRACT

This article examines the concept of concurrent engineering and presents a framework for evaluating its management. The key organizational concepts for managing new product development are first analyzed from a historical perspective. The concurrent engineering approach to new product development is then contrasted with both the traditional sequential and the more recent overlapping problem-solving approaches. Finally, a model for managing current engineering is presented. The model consists of five critical components that may be used by engineering managers for guiding the implementation of their concurrent engineering efforts.  相似文献   
35.
Food Science and Biotechnology - The aim of this study was to investigate the combined effects of Diospyros lotus leaves extracts (DLE) and Muscat Bailey A grape stalk extracts (MGSE) in obesity...  相似文献   
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A mathematical and numerical investigations on the gas–liquid absorption of carbon dioxide in monoethanolamine solutions in a hollow fiber membrane contactor device is described. The reactive absorption mechanism was built based on momentum and mass transport conservation laws in all three compartments involved in the process, i.e., the gas phase, the membrane barrier, and the liquid phase. The liquid absorbing solution flows in the fiber bore in which the velocity is assumed to obey a fully developed laminar flow, and the gas mixture circulates counter‐currently to the liquid flow in the shell side where the velocity is characterized by the Navier‐Stokes momentum balance equations. The average outlet gas and liquid concentrations, the reactive absorption flux, and the gas removal efficiencies are parametrically simulated with operational parameters such as gas flow rate, fresh inlet amine concentrations, and fiber geometrical characteristics. The shell velocity was described by other flow hydrodynamics models besides Navier‐Stokes and their simulated results were favorably compared to experimental data. © 2011 American Institute of Chemical Engineers AIChE J, 2012  相似文献   
39.
Oxalic acid is chosen as a model compound to study the UV + O3 reactions in an heterogeneous continuous gas sparging reactor. Oxalic acid has the advantage of not reacting significantly with ozone alone, and when oxidized with O3 + UV radiation, the reaction is of the single-step type : HOOC-COOH + O3 (UV) = 2 CO2 + H2O + O2. The reactions are of zero order as long as no additional alkalinity is introduced into the system. Evidence is that the photolysis of ozone is produced in the gas phase and that the reaction occurs in the gas-liquid boundary layer.  相似文献   
40.
The Anton Paar Powder Cell was used to measure the torque necessary to rotate an impeller in beds of glass beads, sand and alumina powders aerated between no aeration to the minimum for fluidization. Measured torque values depend on the material tested, on the air flow rate applied, on the impeller depth and on the height of the impeller blade. The effect of the impeller depth is linear for low impeller depth and is less than linear at high depth values. A model was developed for the interpretation of the experimental results based on the idea that the material is shearing on the surface described by the impeller rotation. The model allows to estimate an effectiveness of the impeller in the torque determination and also to predict the torque for the impeller at the at deepest positions at which the wall effects have to be considered. © 2017 American Institute of Chemical Engineers AIChE J, 2017  相似文献   
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