As-molded shrinkage measurements on polystyrene injection molded products

An experimental study of shrinkage in injection molded products is presented in this paper and documented with all information needed for any further analysis. In particular, the effect of holding pressure, holding time and mold geometry on product shrinkage was investigated for amorphous polystyrene. It turned out with increasing holding pressure the in-plane shrinkages varied from 0.6% to 0.1%, while the product thickness increased from about 1% to 10%. The holding time only affected product shrinkage for settings less than gate freeze-off time. Shrinkage usually increases along the flow path unless back flow sets in at the end of the holding stage. It was also found that if a constraint prevents in-mold shrinkage to take place, final shrinkage may decrease if holding pressure and time are small. The effects of all the variables analyzed were described by a thermomechanical model recently proposed.     

Reactions Catalyzed by Pentacyanocobaltate(II)

As early as a century ago Descamps[1] noted that solutions of cobaltous salts evolved hydrogen in the presence of cyanide ion. Yet it was not until 1942[2,3] that Iguchi observed that such solutions were able to absorb molecular hydrogen and transfer it to substrates.     

Peanuts,Peanut Oil,and Fat Free Peanut Flour Reduced Cardiovascular Disease Risk Factors and the Development of Atherosclerosis in Syrian Golden Hamsters

ABSTRACT: Human clinical trials have demonstrated the cardiovascular protective properties of peanuts and peanut oil in decreasing total and low density lipoprotein cholesterol (LDL-C) without reducing high density lipoprotein cholesterol (HDL-C). The cardiovascular effects of the nonlipid portion of peanuts has not been evaluated even though that fraction contains arginine, flavonoids, folates, and other compounds that have been linked to cardiovascular health. The objective of this study was to evaluate the effects of fat free peanut flour (FFPF), peanuts, and peanut oil on cardiovascular disease (CVD) risk factors and the development of atherosclerosis in male Syrian golden hamsters. Each experimental diet group was fed a high fat, high cholesterol diet with various peanut components (FFPF, peanut oil, or peanuts) substituted for similar metabolic components in the control diet. Tissues were collected at week 0, 12, 18, and 24. Total plasma cholesterol (TPC), LDL-C, and HDL-C distributions were determined by high-performance gel filtration chromatography, while aortic total cholesterol (TC) and cholesteryl ester (CE) were determined by gas liquid chromatography. Peanuts, peanut oil, and FFPF diet groups had significantly (P < 0.05) lower TPC, non-HDL-C than the control group beginning at about 12 wk and continuing through the 24-wk study. HDL-C was not significantly different among the diet groups. Peanut and peanut component diets retarded an increase in TC and CE. Because CE is an indicator of the development of atherosclerosis this study demonstrated that peanuts, peanut oil, and FFPF retarded the development of atherosclerosis in animals consuming an atherosclerosis inducing diet.     

Dynamic pH model for autotrophic growth of microalgae in photobioreactor: A tool for monitoring and control purposes

A dynamic model for the photoautotrophic growth of microalgae in photobioreactor that describes the main variables of the system and allows the precise prediction of the pH in the culture was proposed and validated. The dynamic behavior of the biological system was expressed through a multistate model in continuous‐time formulation, based on mass‐balance equations and local photosynthetic responses of the anisotropic medium, further associated with a set of algebraic equations that describes the thermodynamic properties of the ammonia—carbon dioxide—water ternary solute system. The global photoautotrophic growth model was validated on experimental data acquired from a torus reactor inoculated with Chlamydomonas reinhardtii cells. The model response was studied in simulation for all identified input variables (dilution rate, incident light intensity, temperature, and flow rates of input gases). © 2013 American Institute of Chemical Engineers AIChE J 60: 585–599, 2014     

Scheduling dense linear algebra operations on multicore processors

State‐of‐the‐art dense linear algebra software, such as the LAPACK and ScaLAPACK libraries, suffers performance losses on multicore processors due to their inability to fully exploit thread‐level parallelism. At the same time, the coarse–grain dataflow model gains popularity as a paradigm for programming multicore architectures. This work looks at implementing classic dense linear algebra workloads, the Cholesky factorization, the QR factorization and the LU factorization, using dynamic data‐driven execution. Two emerging approaches to implementing coarse–grain dataflow are examined, the model of nested parallelism, represented by the Cilk framework, and the model of parallelism expressed through an arbitrary Direct Acyclic Graph, represented by the SMP Superscalar framework. Performance and coding effort are analyzed and compared against code manually parallelized at the thread level. Copyright © 2009 John Wiley & Sons, Ltd.     

Urinary arsenic methylation and porphyrin profile of C57Bl/6J mice chronically exposed to sodium arsenate

Arsenic interferes with the function of enzymes responsible for haem biosynthesis leading to alteration in the porphyrin profile. In this study, young female C57Bl/6J mice were given drinking water containing 0, 100, 250 and 500 microg As(V)/L as sodium arsenate ad libitum for 24 months. 24 h pooled urine samples were collected bimonthly for urinary arsenic methylation and porphyrin analyses by HPLC-ICP-MS and HPLC respectively. The levels of total arsenic were significantly dose related except for the 2nd month interval. No significant differences in the urinary arsenic methylation pattern between control and test groups were observed. Coproporphyrin I (Copro I) showed a significant dose-response relationship after 12, 14 and 20 months of exposure. Significant differences in the levels of coproporphyrin III (Copro III) were observed in the 8th month in 250 and 500 microg/L treatment groups and the dose-response pattern was maintained after 10 and 12 months. Our results suggest that urinary arsenic is a useful biomarker for internal dose, and that urinary coproporphyrin can be used as an early warning biomarker of effects before the onset of cancer.