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61.
Marc Blumenau Afrooz Barnoush Ingo Thomas Harald Hofmann Horst Vehoff 《Surface & coatings technology》2011,205(2-3):542-552
The present study discusses the impact of selective oxidation during in-line annealing of Fe–23%Mn–0.6%C–0.3%Si steel on surface and sub-surface properties and is focused on hot-dip galvanizability and susceptibility to hydrogen-induced delayed cracking. Annealing temperature (700–1100 °C) and dewpoint DP (? 15/?30/?50 °C) of the 5%H2–N2 annealing atmosphere were varied in order to investigate Zn wetting in dependence on selective oxidation of Mn and Si. Sub-surface microplasticity (hardness, pop-in frequency, pop-in activation load) was examined by electrochemical nanoindentation in-situ to hydrogen charging (ECNI) to assess hydrogen/material interactions. Zn wetting fails if external Mn and Si oxidation is not avoided by performing high reductive bright annealing (1100 °C/DP ? 50 °C). Zn wetting will however turn to increase if a roughly globular MnO layer appears and Si is internally oxidized (700–900 °C/DP ? 15 °C). Selective oxidation further affects hydrogen/material interactions by influencing the local distribution of solid-soluted Mn: ECNI results indicate hydrogen-induced dislocation demobilization (HEDE mechanism) or dislocation mobilization (HELP mechanism) in dependence on the local amount of solid-soluted Mn within the sub-surface. Macroscopic delayed cracking seems to occur earlier if HELP is predominating. The gained results benefit understanding the impact of selective oxidation on galvanizability and susceptibility to hydrogen-induced failure of austenitic FeMnC steel and advance further developments in processing high Mn alloyed steels. 相似文献
62.
Marta Lubary Theo W. de LoosJoop H. ter Horst Gerard W. Hofland 《The Journal of Supercritical Fluids》2011,55(3):1079-1088
The ScMM (Supercritical Melt Micronization) process was applied for the production of microparticles from anhydrous milk fat (AMF) and a diacylglycerol-based modified milk fat (D-AMF). Both fats were able to dissolve ca. 30 wt% CO2 in the studied pressure and temperature ranges, being the CO2 amount slightly higher for AMF. A melting point depression was observed in both systems in the presence of CO2. Two powder morphologies were obtained (spherical hollow particles and a mass sponge-like broken particles) depending on the ScMM process conditions. The concentration of CO2 in the fat melt was the main process variable affecting the particle morphology, followed by the temperature of the melt. The small broken particles originated from the breakage of spherical fat particles that solidified before all CO2 could escape from the atomized droplets. While the hollow spheres had a tendency to agglomerate, the broken microparticles constituted a free-flowing powder as long as they were stored at low temperatures (up to −18 °C). Both types of particles have a potential for being incorporated in refrigerated or frozen food products as a structuring agent. 相似文献
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64.
Energy is the lynchpin of modern society. Since the early 1970s, growing dependence on foreign energy sources, oil in particular, has constrained US independence in foreign policy, and at times, inhibited economic stability and growth. Addressing oil dependence is politically and economically complex. Proposed solutions are multifaceted with various objectives such as energy efficiency and resource substitution. One solution is the partial transition from an oil- to coal-based economy. A number of facts support this solution including vast coal reserves in the US and the relative price stability of coal. However, several roadblocks exist. These include uncertain recoverable reserves and the immaturity of “clean” coal technologies. This paper provides a first order analysis of the most efficient use of coal assuming the transition from oil to coal is desirable. Scenario analysis indicates two possible transition pathways: (1) bring the transportation sector onto the electric grid and (2) use coal-to-liquid fuels to directly power vehicles. The feasibility of each pathway is examined based on economic and environmental factors, among which are energy availability, affordability and efficiency, and environmental sustainability. Results indicate that partial transition of the transportation sector onto the electric grid offers the more viable solution for coal-based reduction of the US oil dependence. 相似文献
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66.
Christian Bergmann Markus Lindner Wen Zhang Karolina Koczur Armin Kirsten Rainer Telle Horst Fischer 《Journal of the European Ceramic Society》2010,30(12):2563-2567
Customized implants for bone replacement are a great help for a surgeon to remodel maxillofacial or craniofacial defects in an esthetical way, and to significantly reduce operation times. The hypothesis of this study was that a composite of β-tricalcium phosphate (β-TCP) and a bioactive glass similar to the 45S5 Henchglass® is suitable to manufacture customized implants via 3D-printing process. The composite was chosen because of the bioresorption properties of the β-TCP, its capability to react as bone cement, and because of the adjustability of the bioactive glass from inert to bioresorbable. Customized implants were manufactured using the 3D-printing technique. The four point bending strength of the printed specimens was 14.9 MPa after sintering. XRD analysis revealed the occurrence of two other phases, CaNaPO4 and CaSiO3, both biocompatible and with the potential of biodegradation. We conclude that it is possible to print tailored bone substitute implants using a bioactive TCP/glass composite. The glass is not involved as reactive substance in the printing process. This offers the opportunity to alter the glass composition and therefore to vary the composition of the implant. 相似文献
67.
Five decades of Computer-Aided Ship Design 总被引:1,自引:0,他引:1
Horst Nowacki Author Vitae 《Computer aided design》2010,42(11):956-969
This article will present a synoptical review of key developments in Computer-Aided Ship Design since its inception about five decades ago. Milestone events and major innovations will be identified in several categories of ship design application with the principal emphasis on the methodologies, the modeling and the integration of the ship design process. The discussion will address many specific subtasks of ship design on the common platform of a human-guided, computer-based decision process. 相似文献
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69.
We propose a method for matching non-affinely related sparse model and data point-sets of identical cardinality, similar spatial distribution and orientation. To establish a one-to-one match, we introduce a new similarity K-dimensional tree. We construct the tree for the model set using spatial sparsity priority order. A corresponding tree for the data set is then constructed, following the sparsity information embedded in the model tree. A matching sequence between the two point sets is generated by traversing the identically structured trees. Experiments on synthetic and real data confirm that this method is applicable to robust spatial matching of sparse point-sets under moderate non-rigid distortion and arbitrary scaling, thus contributing to non-rigid point-pattern matching. 相似文献
70.