			Home About us Contact

Material Transfer (material + transfer)

Distribution by Scientific Domains

Polymers and Materials Science	28%

Selected Abstracts

Phase Reorganization in Self-Assembled Systems Through Interparticle Material Transfer,

ADVANCED MATERIALS, Issue 10 2007
C. Moitzi
Transfer of material occurs when internally nanostructured emulsion droplets of different composition are mixed. This happens without droplet fusion. As the internal structure is dependent on the composition, the transfer can be followed by monitoring these changes using time-resolved small angle X-ray scattering (SAXS; see figure). [source]

Scheduling multistage batch plants with sequence-dependent changeovers

AICHE JOURNAL, Issue 8 2009
Pedro M. Castro
Abstract This article deals with the optimal short-term scheduling of multistage batch plants with parallel units and sequence-dependent changeovers, together with the optimal selection of the number and size of batches to be produced. A new resource-task network-based, multiple time-grid continuous-time formulation is proposed that explicitly considers a virtual, shared, intermediate storage unit per stage to keep track of material transfer between processing units belonging to consecutive stages of production. Adequate material transfer is implicitly ensured through mass balances and timing constraints relating the times of event points of dissimilar grids. The new formulation is compared with a conceptually different approach from another research group. The results for several example problems show that the new formulation is tighter, typically requiring fewer event points to find the global optimal solution, and is significantly more efficient computationally. The results also show that for single batch problems other approaches are preferable. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Orchid mycorrhiza: implications of a mycophagous life style

OIKOS, Issue 3 2009
Hanne N. Rasmussen
Orchid mycorrhiza probably affects about 25,000 plant species and thus roughly one tenth of all higher plants. Histologically, this symbiosis resembles other kinds of endomycorrhiza, the fungal hyphae growing within living plant cells. Considerable evidence, however, suggests that it is not a two-way exchange relationship and thus not potentially mutualistic, such as the wide-spread endomycorrhiza between plants and Glomalean fungi, known as arbuscular mycorrhiza. During the achlorophyllous seedling stage orchids are obligately dependent on the fungi; some species remain so through life, while others establish photosynthesis but to varying degrees remain facultatively dependent of /responsive to fungal infection as adults. None of the fungi involved are so far known to depend on the symbiosis with orchids. Transfer of organic carbon compounds from hyphae to the orchid has been demonstrated repeatedly, but it is not clear to what extent this takes place during a biotrophic phase while the intracellular hyphae remain intact, or during the subsequent extensive degradation of the hyphal coils. The advantage of viewing orchid mycorrhiza basically as a unilateral mycophagous relationship, in spite of hypothetical beneficial spin-offs to the mycobiont, is that it provides a conceptual framework similar to that of other parasitic or fungivore relationships; mechanisms known in such relationships could be searched for in future studies of the orchid,fungus symbiosis. These could include mechanisms for recognition, attraction and selection of fungi, physiological regulation of internal hyphal growth, breakdown, and material transfer, nutritional consequences of the plant's preference(s) and trophic changes, fungal avoidance mechanisms, and consequences at population and ecosystem levels. A whole range of possible life strategies becomes apparent that could support divergent evolution and lead to the proliferation of species that has indeed occurred in the orchid family. We outline some of the possible physiological mechanisms and ecological implications of this approach. [source]

Determination of stability of MIG/MAG welding processes

QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 5 2001
Marjan Suban
Abstract The paper treats several methods of evaluating the stability of MIG/MAG welding processes, which are based on measurement of time-varying welding-current intensity and welding voltage. The stability of the welding process is affected by numerous parameters. The most unfavourable result of poor stability are spatters, which are problematic in terms of material losses and extension of production times due to cleaning, as well as appearance. The experimental part of the paper is based on stability analyses carried out with three different gas-shielding atmospheres. Two different welding domains were compared. The first was short-circuit material transfer, and the second spraying material transfer. The results obtained in the analysis of the signals measured indicate a more stable short-circuit material transfer in the case of welding with the pure CO gas, and a more stable spray material transfer in the case of welding with the transferred ionized molten energy mixture. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Mechanical Study of High Resistance Silicon Carbide Based Multi-Nano-Layers Grown by Multifrequency PACVD

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Farida Rebib
Abstract Titanium alloys are commonly used to lighten aeronautical structures. Unfortunately, their poor tribological properties need to confer onto the surface both high mechanical resistance under load and low friction/low wear against other metals. Based on amorphous silicon carbide (a-SiC:H), periodic multi-nano-coatings have been found to be candidates for this use. Such coatings were deposited on Ti surfaces using multifrequency plasma CVD devices. Scratch-testing measurements have revealed that the critical loads corresponding to cohesive/adhesive cracks are significantly increased using multilayered stacks. Fretting-wear tests also revealed the influence of multilayer architecture and preliminary analysis of wear tracks and material transfers leaded to a first classification of the coatings. [source]