Physicochemical Properties of Surimi Seafood as Affected by Electron Beam and Heat

Physicochemical changes of surimi seafood under electron beam (e‐beam) and heat were investigated. Heat caused color browning and texture softening. E‐beam (up to 4 kGy) deteriorated neither color nor texture when the sample temperatures were between 5 and 23°C. However, firmer texture was measured when samples were treated by e‐beam while frozen. None of the treatments changed rancidity of surimi seafood within the parameters tested. Heat, as compared with e‐beam, generated the same headspace volatiles, however, to a greater extent. E‐beam was determined to be an excellent pasteurization alternative for surimi seafood in terms of retention of fresh‐like physicochemical attributes.     

Textural and microstructural transformation of Cu damascene interconnects after annealing

Influence of annealing on the textural and microstructural transformation of Cu interconnects having various line widths is investigated. Two types of annealing steps have been considered here: room temperature over 6 months and 200°C for 10 min. The texture was determined by x-ray diffraction (XRD) of various cross-sectional profiles after electropolishing, and the surface, microstructure, and grain boundary character distribution (GBCD) of Cu interconnects were characterized using electron backscattered diffraction (EBSD) techniques. In order to analyze a relationship between the stress distribution and textural evolution in the samples, microstresses were calculated with decreasing line widths at 200°C using finite element modeling (FEM). In this investigation, it was found that the inhomogeneity of stress distribution in Cu interconnects is an important factor, which is necessary for understanding textural transformation after annealing. A new interpretation of textural evolution in damascene interconnects lines after annealing is suggested, based on the state of stress and the growth mechanisms of Cu electrodeposits.     

Image analysis of X-ray microtomograms of soft materials during convective drying: 3D measurements

Drying dewatered sludge leads to a complex three-dimensional porous structure. Moreover, this operation is dependent on the way the material is processed. In this study, textural changes of sludge extrudates submitted to convective drying are followed by a 3D image analysis of reconstructed X-ray microtomograms. To achieve this goal, two different wastewater sludges collected in wastewater treatment plant after the thickening step and dewatered in the laboratory are used. It is showed that the evolution of the 3D-crack ratio vs. the residual water content evolves following a hyperbolic law. The 3D opening crack size distribution reveals two different types of pore development, i.e. a continuous pore size evolution for one sludge and the sudden appearance of cracks for the other sludge.     

The effects of substrate bias,substrate temperature,and pulse frequency on the microstructures of chromium nitride coatings deposited by pulsed direct current reactive magnetron sputtering

Recently, great attention has been devoted to the pulsed direct current (DC) reactive magnetron sputtering technique, due to its ability to reduce arcing and target poisoning, and its capability of producing insulating thin films. In this study, chromium nitride (CrN) coatings were deposited by the bipolar symmetric pulsed DC magnetron reactive sputtering process at different pulse frequency, substrate bias voltage, and the substrate temperature. It was observed that the texture of CrN changed from (111) to (200) as substrate temperature increased to 300°C as deposited at 2 kHz without substrate bias. With increasing pulsing bias and pulse frequency of target, predominated (200) orientation of CrN film was shown due to the ion bombardment/channeling effect to preferentially sputter those unaligned planes. For the CrN coatings deposited with pulsed biasing, the grain size decreased with increasing pulse frequency and substrate bias, whereas the surface roughness showed a reverse trend. The deposition rate of the CrN films decreased with increasing pulse frequency. It was concluded that the pulse frequency, substrate bias, and substrate temperature played important role in the texture, microstructure, and surface roughness of the CrN coatings deposited by the pulsed DC magnetron sputtering process.     

Deformation Mechanisms of Ti-6Al-4V During Tensile Behavior at Low Strain Rate

A superplastic Ti-6Al-4V grade has been deformed at a strain rate of 5 × 10⁻⁴ s⁻¹ and at temperatures up to 1050 °C. Structural mechanisms like grain boundary sliding, dynamic recrystallization, and dynamic grain growth, occurring during deformation, have been investigated and mechanical properties such as flow stress, strain hardening, and strain at rupture have been determined. Dynamic recrystallization (DRX) brings on a decrease in the grain size. This could be of great interest because a smaller grain size allows a decrease in temperature for superplastic forming. For DRX, the driving force present in the deformed microstructure must be high enough. This means the temperature must be sufficiently low to ensure storing of enough dislocation energy but must also be high enough to provide the activation energy needed for DRX and to allow superplastic deformation. The best compromise for the temperature was found to be situated at about 800 °C; this is quite a bit lower than the 925 °C referenced in the literature as the optimum for the superplastic deformation. At this medium temperature the engineering strain that could be reached exceeds 400%, a value high enough to ensure the industrial production of complex parts by the way of the superplastic forming. Microstructural, EBSD, and mechanical investigations were used to describe the observed mechanisms, some of which are concurrent. This article was presented at the AeroMat Conference, International Symposium on Superplasticity and Superplastic Forming (SPF) held in Seattle, WA, June 6-9, 2005.     

Physical and Sensory Characteristics of Low Fat Ground Beef Patties

Ground beef patties with combinations of 0 and 10% added water and 0 and 0.25% added phosphate were compared with controls (22% fat and 0% added water and phosphate). Added water increased thaw and cooking losses but improved objective texture measurements and sensory panel ratings (P < 0.05). Added water and phosphate increased the percentage of water, decreased protein and did not affect fat. Added water and/or phosphate resulted in higher (P < 0.05) juiciness, tenderness and overall palatability scores. Low fat patties with added water were similar to 22% fat patties. Water and/or phosphate also improved sensory ratings for texture and flavor of 10% fat patties to equal those for 22% fat patties.     

Contribution of triglycerides from cocoa butter to the physical properties of milkfat fractions

Milkfat was separated into major chainlength fractions by solid-phase extraction. The effect on thermal behavior and texture of replacing both saturated and monounsaturated long-chain triglycerides from milkfat by long-chain monounsaturated triglycerides with an unsaturated fatty acid in thesn-2 position is reported. Increasing proportions of cocoa butter were added to fractions of short-to medium-chain triglycerides (C₂₂−C₄₄) and medium- to long-chain triglycerides (C₃₆−C₄₈) isolated from milkfat. Thermal behavior and texture of the mixtures were measured. Results indicated that long-chain monounsaturated triglycerides from cocoa butter enhanced co-crystallization and co-operative melting and did not induce polymorphic transitions upon crystallization and melting of the fractions. At 4°C, they acted as texture builder if present in proportions of more than 30%, whereas below this level, they acted as texture softeners. The effect of the long-chain monounsaturated triglycerides on the texture of fractions that melt at low temperature could not be predicted from the proportion of solid fat at that temperature. Presented at the 1995 AOCS Annual Meeting & Expo, San Antonio, Texas, May 1995.     

Mass Transfer and Textural Changes during Processing of Apples by Combined Methods

Mass transfer and textural changes of ‘Red Delicious’ apple slices and cylinders during osmotic adjustment of a_w by the combined method approach were studied at 30, 40 and 50°C. Mass transfer of water and sugar in the treated apple followed typical log-normal behavior with most changes occurring during early stages of the process. The changes followed Crank's equation for diffusion. A negative correlation between apple texture and sugar diffusion was observed. Softening, as well as mass transfer changes, occurred at early stages of osmotic treatment. The texture changes were most pronounced at the edges of the apple tissue where the sugar had penetrated. Softening and sugar uptake were more pronounced when apples were acidified. Apples became firm within 2 hr of the process, when the external layer of the apple cylinders penetrated by sugar was trimmed. Calcium chloride beyond 0.30% minimized tissue softening, but the typical crispy structure of the fresh apple was not restored.     

体验材料的表现力、发掘创造性思维--在立体构成教学中对材料感受的拓展

在立体构成课的造型训练中，利用简单的基本材料的限制，开发学生的创造性思雏，使非专业人员看来平淡无奇、能力有限的常规材料，在专业设计者手中成为表现力无限的常新材料。