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Microstructure Formation (microstructure + formation)
Selected AbstractsMicrostructure Formation and Property of Chitosan-Poly(acrylic acid) Nanoparticles Prepared by Macromolecular ComplexMACROMOLECULAR BIOSCIENCE, Issue 12 2005Article first published online: 23 NOV 200 [source] Microstructure Formation and Property of Chitosan-Poly(acrylic acid) Nanoparticles Prepared by Macromolecular ComplexMACROMOLECULAR BIOSCIENCE, Issue 10 2005Qi Chen Abstract Summary: We report here a study on the microstructure formation process of polymeric nanoparticles based on polyelectrolyte complexes. When polyanion poly(acrylic acid) (PAA) was dropped into polycation chitosan (CS) solution, CS-PAA nanoparticles with diverse microstructure would be formed under different experimental conditions. The microstructure of CS-PAA nanoparticles changed from solid spherical nanoparticles to core-shell separative ones and turned back to solid spherical ones with the variation of preparation conditions. The influence of molecular weight of CS and PAA, shell cross-linking, dropping temperature on the size, stability and morphology of CS-PAA nanoparticles were also studied. The nanoparticle size was affected by the molecular weight of CS and PAA, the ratio of amino group to carboxyl group (na/nc) and the incubation temperature as well. The shell-cross-linking provides a means to stabilize these nanoparticles. These nanoparticles can encapsulate plasmid DNA very well, which makes them have great potential in gene delivery. Microstructure of non-cross-linked CS-PAA nanoparticles, encapsulated plasmid DNA, at various na/nc. [source] Modelling of Hot Ductility during Solidification of Steel Grades in Continuous Casting , Part II,ADVANCED ENGINEERING MATERIALS, Issue 3 2010Bernd Böttger In continuous casting, the probability of hot cracks developing strongly depends on the local solidification process and the microstructure formation. In ref. 1, an integrative model for hot cracking of the initial solid shell is developed. This paper focuses on solidification modelling, which plays an important role in the integrated approach. Solidification is simulated using a multiphase-field model, coupled online to thermodynamic and diffusion databases and using an integrated 1D temperature solver to describe the local temperature field. Less-complex microsegregation models are discussed for comparison. The results are compared to EDX results from strand samples of different steel grades. [source] Characteristics and oil absorption of deep-fat fried dough prepared from ball-milled wheat flourJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2009Pariya Thanatuksorn Abstract BACKGROUND: High levels of oil in fried products has been recognized as causing health problems. The formation of microstructure during frying is one factor that influences oil absorption. Above the glass transition temperature (Tg), the physical properties of a polymer influences the formation of structure. The ball-milling process changes the physicochemical properties of wheat flour constituents. The present study investigated the effects of physicochemical changes in wheat flour by the ball-milling process on structure formation and oil absorption in wheat flour dough model. RESULTS: Dough samples were made from wheat flour that had been ball-milled for 0 to 10 h and then fried in frying oil at 150 °C for 1,7 min. Thermal properties of wheat flour, structure alteration, and textural properties of fried samples were evaluated. As compared with samples made of non-milled flour, samples made from milled flour had smaller pores and higher oil absorption. The fracture force of a fried sample prepared from non-milled flour was lower than that of a sample prepared from milled flour. CONCLUSION: Ball-milling affected the microstructure formation in fried wheat flour dough, and subsequently oil absorption. The crispness of a sample prepared from non-milled wheat flour is higher than that of a sample prepared from ball-milled wheat flour. This may be due not only to a plasticization effect, but may also be dependent on microstructure. Copyright © 2008 Society of Chemical Industry [source] Micro-fabrication and monitoring of three-dimensional microstructures based on laser-induced thermoplastic formationMICROSCOPY RESEARCH AND TECHNIQUE, Issue 10 2009Leyan Wang Abstract This article reports a novel laser-induced micro-fabrication method and its monitoring system for three-dimensional (3D) microstructures. The mechanism of the method is that a small zone of thermoplastic material melted by laser heating grows in liquid surrounding environment, solidifying into a convex microstructure, such as micro-dot or micro-pillar. A laser diode (808 nm) with maximum power output of 130 mW is used as power source, and a kind of paraffin mixed with stearic acid and paint serves as the thermoplastic material for 3D microstructure formation experiments. A light microscope system consisting of a charge-coupled device (CCD) and a computer is utilized to realize real-time observation of the micro-fabricating process. The distribution of local temperature rise on material surface created by laser irradiation is simulated. The effects of liquid environment on microstructure formation have been theoretically analyzed and experimentally studied. Experiments are further carried out to investigate the relationship between laser spot and fabricated microstructures. The results indicate that the widths of micro-dots or micro-pillars are mostly determined by the size of focal spot, and their heights increase with the enlargement of laser power density. With this method, a micro-dot array of Chinese characters meaning "China" has been successfully fabricated through computer programming. This method has the advantages of implementing direct, mask-less, real-time and inexpensive 3D microstructure fabrication. Therefore, it would be widely applied in the fields of micro/nano-technology for practical fabrication of different kinds of 3D microstructures. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source] Influence of dynamic structure on the microstructure formation of a steel surface in the electrolyte in a steady magnetic fieldPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004Svetlana Gorobets Abstract The periodic microfabrication effect of metal element surfaces in an electrolyte solution in an external steady magnetic field was investigated. Authors have shown that corrosion velocity and periodic microstructure formation on the metal element surface can be controlled by magnetic field application. Geometric configuration of periodic microstructure depends on metal element characteristics, electrolyte solution, treatment time, magnetic field magnitude and other parameters. Investigation results have shown possibility of magnetic field influence on hydrodynamic conditions and metal surface structure under its etching in the nitric acid solution. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Food Process Engineering: The Last 25 Years and Challenges AheadCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 2 2003S. Bruin ABSTRACT In the first part of this contribution, an overview is given of some of the main developments in food process engineering in the last 25 years of the 20th century. This overview is, of course, colored by the personal experience of the authors, but a sincere effort was made to maintain a general perspective. Topics that will be briefly discussed are: progress in understanding how to control food microstructure formation during processing, separation processes, conversion processes and stabilization processes, progress in flavor technology and understanding of flavor retention during processing and release. In the 2nd part, in our view, the most exiting future developments are briefly discussed. The major items here are: processing requirements for functional foods, integrated process design approaches, application of novel,fields'in food processes,,precision'processing, supply chain approaches to food manufacturing, and more. [source] | ||||||||||