Epsilon Flock: a model migration language

Model-driven engineering introduces additional challenges for controlling and managing software evolution. Today, tools exist for generating model editors and for managing models with transformation, validation, merging and weaving. There is limited support, however, for model migration—a development activity in which instance models are updated in response to metamodel evolution. In this paper, we propose conservative copy—a style of model transformation that we believe is well-suited to model migration—and Epsilon Flock—a compact model-to-model transformation language tailored for model migration. The proposed structures are evaluated by comparing the conciseness of model migration strategies written in different styles of transformation language, using several examples of evolution taken from UML and the graphical modelling framework.     

Modification of industrial polypropylene film by grafting of poly(acrylic acid)

Grafting of poly(acrylic acid) onto commercial polypropylene films following irradiation by γ-rays was carried out in order to improve their surface properties. The amount of grafting with the irradiation dose was found not to follow the expected linear dependence as it is normally observed for polypropylene films prepared in laboratory amounts. We therefore analyzed the influence of the industrial manufacture process in terms of orientation of the film and addition of antioxidants by determining the peroxide surface density and the extent of grafting therefrom. The unoriented polypropylene film presented the highest peroxide concentration and was thus the most adapated material for successful grafting. Whereas phenol antioxidants limit the peroxide formation and thus must be removed from the film for grafting, the thickness of the chemical modification and can be controlled by means of phosphites. Atomicforce microscopy and wettability measurements showed that the grafted poly(acrylic acid) was heterogeneously distributed on the surface of the film, explaining the observed low reproducibility of the grafting reaction. However, we observed that the polarity of the surface was increased by the grafting. © 1995 John Wiley & Sons, Inc.     

Gas/liquid dispersions with a SMX static mixer in the laminar regime

A Sulzer SMX mixer was used to disperse gas into viscous, Newtonian and non-Newtonian fluids. The investigation covered the effect of the dispersed phase volume fraction, the viscosity of the continuous phase, the mixer length and the power draw. The flow regime was kept laminar in all the experiments. The dispersion of gas was carried out with gas concentrations between 1% and 7% in volume. Using the “process viscosity” concept, it was possible to collapse all the measured sizes on a single master curve by using the energy consumption in the mixer as the common variable between the experiments. Comparison was made with a Kenics mixer. The SMX mixer was found to be better adapted to the dispersion task due to its internal structure.     

A review of the unique features of HDL apoproteins

The human plasma high density lipoproteins (HDL) are a heterogeneous ensemble of five proteins associated with both neutral and polar lipids. The sequences of all five proteins are known. ApoA-I and apoA-II are the major protein components; apoC-I, apoC-II and apoC-III are the minor protein components. All these apoproteins spontaneously recombine with phospholipids to give stable lipid-protein complexes and freely exchange between the two major HDL subclasses, HDL₂ and HDL₃. In addition, ApoC-I, apoC-II, and apoC-III exchange between HDL and very low density lipoproteins. Furthermore, certain HDL apoproteins are activators for plasma enzymes that are important in lipid metabolism. ApoA-I and apoC-I activate lecithin/cholesterol acyltransferase; apoC-II is an activator of lipoprotein lipase. The regions of apoC-I and apoC-II that are involved in the activation of these enzymes have been localized with synthetic peptides. Studies of synthetic and native fragments of apoA-II, apoC-I, apoC-II, and apoC-III as well as model lipid-binding peptides have identified specific regions with structural features common to lipid-binding proteins. These special properties, which include helical potential, sequences with a critical amphipathic length, and high hydrophobicity of the nonpolar side of the amphipathic helix, are the determinants of HDL structure and metabolism.     

两株抗氧化活性酵母的鉴定及对乳成分的影响

为获得有抗氧化活性的工业用酵母菌株,对2株来源于原料乳中有较强抗氧化活性的酵母菌进行鉴定.根据菌株的表型、生理生化特征和基因型的特性,初步将这2株菌鉴定为毕赤氏发酵酵母(Pichia fermentans).将这2株酵母菌在高温灭菌(UHT)牛乳中培养以研究其对牛乳主要成分的影响,结果表明:这2株酵母能在UHT牛乳中产乙醇,具有促进蛋白水解活性与脂肪水解活性的能力,能有效提高乳中的游离氨基酸和脂肪酸的含量.     

THE SINGLE PELLET DIFFUSION REACTOR: THEORY AND APPLICATIONS

Most heterogeneous catalysts are either supported on some kind of porous material or the catalyst itself is porous. To satisfy practical constraints such as pressure drop, handling, and separation from products, these catalysts are generally pelletized. Very often the overall chemical reaction rates within these catalyst pellets are determined by a complicated interaction of internal and external transport effects with the intrinsic kinetic rate at the active surface.     

The time dependent strain potential function for a polymeric glass

Torsion and normal force measurements were made during single step stress relaxation experiments on a polymeric glass (PMMA). Isochronal data were analysed using an approach adapted from that developed by Penn and Kearsley¹ (for incompressible elastic materials) to determine the derivatives $\text{?W}\text{?I}{}_1$, and $\text{?W}\text{?I}{}_2$ of the time dependent strain potential function. $\text{?W}\text{?I}{}_1$ and $\text{?W}\text{?I}{}_2$ are determined from existing solution to the torsion of an incompressible cylinder. A special solution to the torsion of a compressible cylinder is presented and it is shown that the values of $\text{?W}\text{?I}{}_1$ and $\text{?W}\text{?I}{}_2$ obtained using this solution to analyse the data do not differ greatly from those obtained using the incompressible solution. It is found from both solutions that $\text{?W}\text{?I}{}_1$ is negative and increases towards zero with increasing time and deformation while $\text{?W}\text{?I}{}_2$ is positive, greater in magnitude than $\text{?W}\text{?I}{}_1$ and decreases towards zero with increasing time and deformation. These results were unexpected and a full understanding of their meaning has yet to be reached.     

Effect of Microstructure on the Tribological and Mechanical Properties of CuO-Doped 3Y-TZP Ceramics

Dense 8 mol% CuO-doped 3Y-TZP ceramics were prepared by pressureless sintering for 8 h at 1500° and 1550°C, respectively. Transmission electron spectroscopy revealed that the ceramic sintered at 1500°C exhibits grain boundaries free of any amorphous phase, while crystalline copper-oxide grains were found in the zirconia matrix, whereas the sample sintered at 1550°C contains a Cu-rich amorphous grain boundary layer. The tribological behavior of these materials was tested under dry-sliding conditions using a pin-on-disk tribometer. The material sintered at 1500°C showed self-lubrication resulting in a low coefficient of friction ( f ) of 0.2–0.3 and a low specific wear rate ( k ) ≪ 10⁻⁶ mm³·(N·m)⁻¹. In contrast, the material sintered at 1550°C showed poor tribological behavior ( f =0.8–0.9; k ≫ 10⁻⁶ mm³·(N·m)⁻¹ under the same conditions. The difference in the tribological behavior of these two materials was interpreted on the basis of mechanical properties and microstructural characteristics.     

Air impingement and intermittent drying: Application to apple and to mango

An original drying process combining air impingement and intermittent drying was studied on apple slices and mango cubes. The influence of four operating parameters (air velocity, drying/tempering periods, upper height, and air temperature) on the drying time and on the drying rate was evaluated. Continuous and intermittent drying were compared. The intermittency α = 1/7 (τ_on = 10 seconds and τ_off = 60 seconds) gave the best results. A time savings of 54% for apple and 67% for mango was reached. In continuous drying, a time savings of 4620 seconds was observed by increasing the air velocity from 6 to 40 m s^?1 for apple. Air temperatures of 328 K for apple and of 328 K or 338 K for mango were determined as optimum to prevent case‐hardening. Experimental results were fitted with the analytical solution of Fick's second law and the modified Page equation (average values R² = 0.985 and 0.961, for apple and mango, respectively). For both products, the apparent moisture diffusivity D_app, the drying constant k, the drying coefficient n, and the activation energy E_a, were identified. Activation energies calculated from the analytical solution were 30.3 and 36.8 kJ mol^?1 and were 25.4 and 30.0 kJ mol^?1 using the modified Page equation for apple and mango, respectively. Mango has an increased temperature sensitivity and thus will need less energy for drying than apple.     

Comparing the Performance of Organic Solvent Nanofiltration Membranes in Non-Polar Solvents

Organic solvent nanofiltration (OSN) is gradually expanding from academic research to industrial implementation. The need for membranes with low and sharp molecular weight cutoffs that are able to operate under aggressive OSN conditions is increasing. However, the lack of comparable and uniform performance data frustrates the screening and membrane selection for processes. Here, a collaboration is presented between several academic and industrial partners analyzing the separation performance of 10 different membranes using three model process mixtures. Membrane materials range from classic polymeric and thin film composites (TFCs) to hybrid ceramic types. The model solutions were chosen to mimic cases relevant to today's industrial use: relatively low molar mass solutes (330–550 Da) in n-heptane, toluene, and anisole.