Thermal stability of poly(methyl methacrylate)

Summary The average solid-state molecular structures of end-groups generated through chain termination reactions in the polymerization of methyl methacrylate have been derived from published crystallographic data. Evidence is provided for the reduced stability of the head-head chain-termination configuration and in support of the postulate that it is a preferred site of chain scission. Comparable evidence for the unsaturated end group has not been found.     

Ceramers: Hybrid materials incorporating polymeric/oligomeric species with inorganic glasses by a sol-gel process

A sol-gel process has been successfully utilized to produce hybrid materials incorporating polymeric/oligomeric components of polydimethyl siloxane(PDMS) with silicon glasses. All the samples made were transparent and flexible. Dynamic mechanical studies indicate that a portion of the siloxane species is phase-separated while the remainder is well dispersed. The effect of acid content were proven to be significant on the dispersion of the siloxane components and on the structure and properties of final products.     

SOLUBILISATION OF NITROGENOUS CONSTITUENTS OF BREWERS' SPENT GRAIN

The extraction of nitrogenous material from Brewers' spent grain (BSG) by solvents (water, sodium chloride solution, aqueous alcohol, acidic and alkaline solutions) commonly used to extract cereal proteins, resulted in the relatively low (0·2 to 8·5%) recovery of the total nitrogen. The recovery of nitrogenous material by the use of aqueous alkaline solutions was increased from 3–4% to 41% when the BSG was subjected to cellulase incubation prior to extraction. Approximately 75% of the nitrogen was solubilized with trifluoracetic acid. Detergent solutions (acid, neutral) solubilized more than 80% of the total nitrogen of the BSG. The low solubility of the nitrogenous constituents by conventional protein solvents could be the result of association between cellulosic material and protein.     

Actions speak no louder than words: Symmetrical cross-modal interference effects in the processing of verbal and gestural information.

Five experiments are reported that investigate the distribution of selective attention to verbal and nonverbal components of an utterance when conflicting information exists in these channels. A Stroop-type interference paradigm is adopted in which attributes from the verbal and nonverbal dimensions are placed into conflict. Static directional (deictic) gestures and corresponding spoken and written words show symmetrical interference (Experiments 1, 2, and 3), as do directional arrows and spoken words (Experiment 4). This symmetry is maintained when the task is switched from a manual keypress to a verbal naming response (Experiment 5), suggesting the mutual influence of the 2 dimensions is independent of spatial stimulus-response compatibility. It is concluded that the results are consistent with a model of interference in which information from pointing gestures and speech is integrated prior to the response selection stage of processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Process-based cost modeling of photonics manufacture: the cost competitiveness of monolithic integration of a 1550-nm DFB laser and an electroabsorptive modulator on an InP platform

The monolithic integration of components holds promise to increase network functionality and reduce packaging expense. Integration also drives down yield due to manufacturing complexity and the compounding of failures across devices. Consensus is lacking on the economically preferred extent of integration. Previous studies on the cost feasibility of integration have used high-level estimation methods. This study instead focuses on accurate-to-industry detail, basing a process-based cost model of device manufacture on data collected from 20 firms across the optoelectronics supply chain. The model presented allows for the definition of process organization, including testing, as well as processing conditions, operational characteristics, and level of automation at each step. This study focuses on the cost implications of integration of a 1550-nm DFB laser with an electroabsorptive modulator on an InP platform. Results show the monolithically integrated design to be more cost competitive over discrete component options regardless of production scale. Dominant cost drivers are packaging, testing, and assembly. Leveraging the technical detail underlying model projections, component alignment, bonding, and metal-organic chemical vapor deposition (MOCVD) are identified as processes where technical improvements are most critical to lowering costs. Such results should encourage exploration of the cost advantages of further integration and focus cost-driven technology development.     

Electrostatic polymer processing of isotactic poly(4-methyl-1-pentene) fibrous membrane

Isotactic poly(4-methyl-1-pentene) (P4M1P) is a widely used polymer in industrial applications and specifically, in medical products. Producing micro- or nanofibers would expand the usefulness of P4M1P to a broad range of medical applications. The choice and quality of solvent for the solution used for electrospinning can have a dramatic effect on the spinnability of fibers and on their morphological appearance. In this study, four solvent systems: cyclohexane, cyclohexane/acetone mixture, cyclohexane/dimethyl formamide (DMF) mixture and cyclohexane/acetone/DMF mixture have been investigated. As demonstrated by FE-SEM, electrospun fibers with different morphologies including round, twisted with a roughened texture, curled and twisted-ribbon shapes were formed. The fiber shape and morphology depended strongly on the type and amount of non-solvent used.     

High‐pressure processing effects on the mechanical,barrier and mass transfer properties of food packaging flexible structures: a critical review

Food products can be high‐pressure processed (HPP) either in bulk or prepackaged in flexible or semi‐rigid packaging materials. In the latter case the packaging material is subjected, together with the food, to high‐pressure treatment. A number of studies have been performed to quantify the effects of high‐pressure processing on the physical and barrier properties of the packaging material, since the integrity of the package during and after processing is of paramount importance to the safety and quality of the food product. This article reviews the results of published research concerning the effect of HPP on packaging materials. Copyright © 2004 John Wiley & Sons, Ltd.     

Stalked by the postmodern beast.

Compares the philosophical positions of K. J. Gergen (see record 1994-37275-001) and M. B. Smith (see record 1994-37277-001) concerning the impact of postmodernism on psychology's scientific foundations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic conversion of triangular finite element meshes to quadrilateral elements

A method is presented for the fully automatic conversion of a general finite element mesh containing triangular elements into a mesh composed of exclusively quadrilateral elements. The initial mesh may be constructed of entirely triangular elements or may consist of a mixture of triangular and quadrilateral elements. The technique used employs heuristic procedures and criteria to selectively combine adjacent triangular elements into quadrilaterals based on preestablished criteria for element quality. Additional procedures are included to eliminate isolated triangles. The methods operates completely without user intervention once the nodal co-ordinates and element connectivity of the original mesh are supplied.