Morphology and properties of blends of polyethylene with a semiflexible liquid crystalline polymer

Blends of three polyethylene (PE) samples (two HDPE grades and LLDPE) with an experimental sample of a semiflexible liquid crystalline polymer (SBH 1:1:2 by Eniricerche) have been prepared in a Brabender compounder. The processing-aid effect of the LCP has been demonstrated by the decreased energy required for extruding the blends, as compared to that needed for neat PE. The thermal properties, as studied by differential scanning calorimetry (DSC), have shown that the two components of the blends are immiscible. However, the dispersed SBH phase has been found to act as a nucleating agent for the crystallization of LLDPE, whereas no such effect was observed for HDPE. This has been taken as an indication that the phase interactions of SBH with LLDPE are more pronounced than with HDPE. The morphological study of the blends, done by scanning electron microscopy (SEM), has confirmed this conclusion. In fact, the SBH particles show a much better dispersion and a narrower size distribution in the LLDPE/SBH blends. The mechanical properties of the blends have been studied on compression-molded specimens. The results indicate that the reinforcing effect of SBH is practically none for both HDPE grades. In fact, the elongation at break decreases to very low values, and the tensile strength is also reduced, when the LCP concentration increases beyond 5–10%, whereas the tensile modulus does not vary appreciably, over the whole (0–20%) LCP range investigated. On the contrary, the tensile modulus of the LLDPE/SBH blends increases up to ca. 50%, and the elongation at break decreases more smoothly, on increasing the SBH content up to 20%. © 1995 John Wiley & Sons, Inc.     

HEMET: mathematical model of biochemical pathways for simulation and prediction of HEpatocyte METabolism

Many computer studies and models have been developed in order to simulate cell biochemical pathways. The difficulty of integrating all the biochemical reactions that occur in a cell in a single model is the main reason for the poor results in the prediction and simulation of cell behaviour under different chemical and physical stimuli. In this paper we have translated biochemical reactions into differential equations for the development of modular model of metabolism of a hepatocyte cultured in static and standard conditions (in a plastic multiwell placed in an incubator at 37 degrees C with 5% of CO(2)). Using biochemical equations and energetic considerations a set of non-linear differential equations has been derived and implemented in Simulink((R)). This set of equations mimics some of the principal metabolic pathways of biomolecules present in the culture medium. The software platform developed is subdivided into separate modules, each one describing a different metabolic pathway; they constitute a library which can be used for developing new modules and models to project, predict and validate cell behaviour in vitro.     

Improved design and optimization models for the fixed bed adsorption of acid dye and zinc ions from effluents

The bed depth service time (BDST) design model, which accounts for the change of bed adsorption capacity with service time, has been modified to expand its application and overcome the limiting assumptions of the original BDST analysis. Column experiments were undertaken to test the new model for two adsorption systems, namely zinc ion–bone char and Acid Blue 80 dye‐activated carbon. It was found that the percentage of saturation capacity could be correlated using a square‐root dependence on the service time and this correlation was incorporated into the original BDST analysis to replace the total sorption capacity term, giving the model a much wider application to real systems. The empty bed residence time optimization approach was modified using the same time‐dependent capacity expression and was successfully applied to the metal ion–bone char and the dye‐activated carbon system with the use of equilibrium saturated bed capacity. These modifications to the BDST design model and the EBRT optimization model will give more accurate scale‐up data for the design of large‐scale column adsorption systems. © 2002 Society of Chemical Industry     

A study on relationships between durum wheat semolina properties,technological mixing parameters and the properties of dough after mixing

Partial least square regression analysis was used to study the correlation between X variables (semolina quality, hydration level and mixing time) and Y variables, which were, in a first model, dough consistency during mixing, and, in a second model, dough properties after mixing (strength, elasticity, density) and leavening (maximum volume). The first model showed a predictive residual sum of squares (PRESS) of 2.98 and a predictive R² (Q²) of 0.92, and highlighted the key role of hydration and mixing time on dough consistency. The second model had the best PRESS (8.25) and Q² (0.94) values for dough volume and indicated that the volume increased with increasing mixing time until the dough consistency decreased of 20–30%. Dough volume was primarily affected by hydration. The model indicated that maximum volume after leavening, corresponding to optimum mixing time, was obtained with a soft and elastic dough, with a low‐density value.     

精益求精 至真至诚,焕然一新的顶级Hi-Fi试听室 力高音响广州海印试听室

谈及中国音响胜地,自然少不了广州海印这块福地。这里几乎浓缩了全世界所有的顶级影音名牌,里面有众多的影音试听室,可以称得上是名副其实的影音器材天地,每个到过广州海印的影音爱好者相信都会不约而同地感受到影音所带来的激动。力高音响作为广州海印地区最具口碑的老字号影音器材代理商之一,秉着精益求精、至真至诚的理念,强调整体影音销售概念,而并非单纯地销售影音设备。力高音响在海印除了Hi-Fi与AV影院两间视听室之外,还拥有具备重要地位的力高名线屋,让广大影音爱好者充分了解到线材、机架、接头等音响配件对于音响系统的重要性。面对目前风靡全球,深受年轻一代喜爱的家庭影院,力高音响可谓业界最早引入家庭影院器材及概念的代理商。近日,力高音响对旗下的Hi-Fi试听室进行重新装葺,让视听室的声音表现更胜一筹,另外还加入影院元素,增添了多声道的音响以及投影系统,让这间以Hi-Fi闻名的试听室更加多元化。本刊记者在其建成后第一时间对其进行了实地采访。     

Investigation of carbon in megabar regime

In this paper experimental measures of the reflectivity change in carbon compressed to megabar pressures are presented. The experiments were performed at ILE, Osaka University. The GEKKO-XII laser facility was used to produce shock waves into “two-layer-two-materials” targets made of porous carbon deposited on a transparent substrate. Target design allowed the exploration of the phase diagram by means of samples with different carbon initial density and exploiting the reflection of the shock wave at the interface between carbon and the denser substrate to increase pressure. At the same time, carbon reflectivity could be probed with a secondary laser pulse through the transparent substrate. Also, shock dynamics has been studied thoroughly with numerical simulations performed with the hydrodynamical-radiative code Multi. An increase in carbon reflectivity was evidenced at 2.5 Mbar and 14,000 K.     

An organization-wide approach for an effective communication system, Part 2

This is the second article in a two-part series that describes an organization's approach to designing, implementing, and evaluating a communication system. Part 1 of this series, published in the March 1998 issue, focused on the design and implementation of this system. This article addresses the evaluation of outcomes related to identified goals to improve communication flow and decision making on multiple levels and to promote accountability for clinical and operational performance. Implementation strategies involving change management, emergence of issues with related implications, and planned evolution of this system also are discussed for ongoing organizational performance improvement.     

Fixed bed modelling for acid dye adsorption onto activated carbon

The adsorption of three separate acid dyes onto activated carbon has been studied using fixed bed adsorption. A film‐pore diffusion model was developed and applied to the experimental breakthrough curve data. A sensitivity analysis showed that pore diffusion was the dominant mass transport mechanism. Pore diffusion coefficients were determined by an optimization routine with a minimization of the sum of errors squared. The external mass transfer coefficients were sensitive to the external fluid dynamic parameters, such as liquid flow rate and mean particle size. These fluid dynamic parameters did not affect the effective diffusion coefficient. The effective diffusion coefficient was not affected by changes in the fluid dynamic parameters but did change with differing initial dye concentrations. This may be due to a contribution from surface diffusion to the effective diffusion coefficient. Copyright © 2003 Society of Chemical Industry     

Measuring the mechanical properties of Pb-free solder and Sn-based intermetallics by nanoindentation

The technique of nanoindentation coupled with an atomic force microscope has been used to measure mechanical properties of Cu-Sn and Ag-Sn intermetallics at length scales similar to those observed in real solder joints. This article describes the experiment and discusses the results in terms of the effect of intermetallics on the reliability of microelectronic packages. The results show that, despite their high hardness, the intermetallics deform plastically without cracking at the small loads and length scales of nanoindentation testing. For more information, contact Richard R. Chromik, Lehigh University, Materials Research Center, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015; (610) 758-6879, fax (610) 758-3526, email chromik@lehigh.edu.     

Serial Position Effects and the Picture-Superiority Effect in the Group Recall of Unshared Information.

This research examined how serial position effects (i.e., primacy and recency effects) and the picture-superiority effect (i.e., the tendency to recall pictures better than words) can impact the recall of unshared information (i.e., information known by only 1 group member). In 2 experiments, participants studied a stimulus list of pictures and words and completed a group recall task. In both experiments, the authors found that the primacy effect and the picture-superiority effect influenced how much unshared information was recalled and when it was recalled. However, there was little impact of the recency effect on either how much unshared information was recalled or when it was recalled. The implications of these findings for future theoretical research and applications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)