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71.
Antoine Le Duigou Jean-Marc Deux Peter Davies Christophe Baley 《Applied Composite Materials》2012,19(3-4):363-378
In the present paper the environmental impact of biocomposites and bio-sandwich materials production are evaluated, using simplified Life Cycle Analysis (LCA) following the procedure recommended in the ISO 14044 standard. The materials are dimensioned and evaluated by comparing with reference materials, glass mat reinforced unsatured polyester and glass mat/unsatured polyester/balsa sandwich. The results indicate that bio-sandwich materials are very attractive in terms environmental impact. However further improvements in biocomposite and bio-sandwich mechanical strength are necessary if they are to be used in transport application compared to glass/polyester and glass/polyester/balsa sandwich. 相似文献
72.
Causes of chatter in a hot strip mill: Observations, qualitative analyses and mathematical modelling
Vladimir Panjkovi? Ronald Gloss John Steward Stephen Dilks Robert StewardGregory Fraser 《Journal of Materials Processing Technology》2012,212(4):954-961
Severe vibrations, known as chatter, occur often in both hot and cold rolling of steel. A recent chatter outbreak at the second stand of hot strip mill in Hastings, Australia, prompted an investigation into the causes of chatter by a literature review, the development and deployment of mathematical models, and a rigorous analysis of plant observations. The investigation suggests that the frictional conditions in the roll gap are the principal cause of chatter in this mill, though residual chatter marks on work rolls can occasionally cause it. The frictional conditions appear to be associated with the thickness and properties of oxide formed on rolls. 相似文献
73.
Experimental evidence of concurrent compositional and structural instabilities leading to ω precipitation in titanium-molybdenum alloys 总被引:1,自引:0,他引:1
A. DevarajS. Nag R. SrinivasanR.E.A. Williams S. BanerjeeR. Banerjee H.L. Fraser 《Acta Materialia》2012,60(2):596-609
The ω phase is commonly observed in many commercial β or near-β titanium alloys on rapidly cooling from the single β phase field and also during subsequent isothermal annealing. However, the crystallographic formation mechanism for the ω particles is hitherto unclear/under discussion. The present study primarily focuses on ω precipitation within the β (body-centered cubic (bcc)) matrix of simple model binary titanium-molybdenum (Ti-Mo) alloys. It provides direct experimental evidence of the formation of ω-like embryos from competing compositional and structural instabilities arising in the bcc lattice of Ti-Mo alloys during rapid cooling from the high-temperature single β phase field. The displacive partial collapse of the {1 1 1} planes of the parent bcc structure within compositionally phase-separated regions containing several at.% less of Mo, forming ω-like embryos, has been conclusively shown by coupling aberration-corrected high-resolution scanning transmission electron microscopy with atom probe tomography observations. Growth and coarsening of these ω-like embryos take place during subsequent isothermal annealing, accompanied with both a completion of the collapse of the {1 1 1} β planes leading to a fully developed ω structure as well as rejection of Mo from these precipitates, resulting in near-equilibrium compositions. 相似文献
74.
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76.
Optimization campaigns, which are being launched more and more often, require the execution of many parametric studies which
can make the approach very costly in terms of computation time. Here, in order to reduce these computation times, we undertake
to develop a multiparametric strategy using the LATIN method along with Proper Generalized Decomposition. This approach is
compared to other common strategies, especially those based on POD. 相似文献
77.
Brahim Bchir Souhail Besbes Romdhane Karoui Michel Paquot Hamadi Attia Christophe Blecker 《Food and Bioprocess Technology》2012,5(3):999-1009
Pomegranate seeds were osmodehydrated using date juice added with sucrose (final °Brix, 55) as immersion solution. The kinetics
of osmotic dehydration showed that the most significant changes of mass transfer took place during the first 20 min of the
process, regardless of date juice varieties. During this time, seed water loss and solid gain were estimated to be ∼39% and
∼6%, respectively. After 20 min of the process, the percentage of water loss and solid gain varied slightly and ranged on
average close to ∼40% and ∼9%, respectively. During osmotic dehydration, there was a leaching of natural solutes from seeds
into the solution, which is quantitatively not negligible, and might have an important impact on the sensorial and nutritional
value of seeds and date juices. Both scanning electron microscopy and texture (compression) analysis revealed that osmotic
dehydration process induced modifications of seed texture and cell structure. Sucrose was found to be the essential element
which influences the texture of seed and the viscosity of date juice. Additionally, natural sugar present in date juice permits
substituting 35% of the total quantity of sucrose added to the osmotic solution. 相似文献
78.
Experimental Data Highlighting the Role of Surface Fracture Energy in Quasi-Static Confined Comminution 总被引:1,自引:0,他引:1
Carlos Ovalle Christophe Dano Pierre-Yves Hicher 《International Journal of Fracture》2013,182(1):123-130
Since the pioneering work of Griffith, Linear Elastic Fracture Mechanics has been widely experimentally validated and successfully developed in solid mechanics modeling. However, recent theoretical models applying the energy balance found in Griffith theory specifically for quasi-static confined comminution have until now not been systematically confronted to experiments. In this study, we analyze data of compression tests on crushable sand, where grain breakage has been triggered by flooding the initially dry material at constant stresses. We consider a partition of the dissipation between surface fracture energy and the rearrangement of fragments and grains surrounding crushed particles. Our results show that the role of the surface fracture energy is stressdependent and that its influence becomes less significant at high stresses. 相似文献
79.
The use of glass fibre reinforced polyester composites raises many health and safety and environmental questions. One alternative is the development of high performance bio-based bio-composites with low environmental impact. Improved understanding of interfacial properties is essential to optimise the mechanical properties and durability of these materials, but so far few data are available. The present work describes the interfacial characterization of Flax fibre/Poly(lactic) acid (PLLA) system at the micro-scale using the microbond test. Different thermal treatments have been carried out (cooling rate and annealing) in order to evaluate the influence of matrix and interfacial morphologies as well as residual stress on interfacial properties. Micromechanical models have been used to determine the interfacial shear strength. When cooling rate is slow, improved interfacial properties are observed. 相似文献
80.
Christophe Chlique David Lambertin Pascal Antonucci Fabien Frizon Philippe Deniard 《Journal of the American Ceramic Society》2015,98(4):1308-1313
The purpose of this work was to study the role of cesium in sodium‐based geopolymer and its thermal stability for nuclear waste management. A series of mixed sodium and cesium geopolymer samples (Na1?x Cs x )2O·Al2O3·SiO2·12H2O (referred to as (Na1? x Cs x )‐GP, where x = 0, 0.08, 0.15, 0.42, 1) have been prepared. All geopolymer samples were heated at 1100°C for 24 h. Pollucite (CsAlSi2O6) and feldspathoid (CsAlSiO4) were crystallized from Cs‐GP. Nepheline (NaAlSiO4) and a small amount of crystallized silica were obtained from Na‐GP. The other geopolymers (Na1? x Cs x )‐GP (x = 0.08, 0.15, 0.42) led to pollucite and nepheline main phases. Amorphous silica phase was observed in all the geopolymer samples with various amounts. Phase quantification and scanning electron microscope revealed that higher Cs concentrations in Na‐GP tend to decrease the amorphous phase while improving pollucite and nepheline phase quantification. The amorphous geopolymers have also been studied by pair distribution function analysis. Tetrahedral chains formed by T–O bonding (with T = Si, Al) were shown to be more tighten around Cs+ than around Na+. It led to shorter Cs–T bond than Na–T bond matching the higher solvation property of Na+. Furthermore, thermal study analysis pointed out the fact that geopolymer samples (Na1? x Cs x )‐GP, can be considered as solid solutions. 相似文献