Thermoplastic olefin/clay nanocomposites: Morphology and mechanical properties

Thermoplastic olefin (TPO)/clay nanocomposites were made with clay loadings of 0.6–6.7 wt %. The morphology of these TPO/clay nanocomposites was investigated with atomic force microscopy, transmission electron microscopy (TEM), and X‐ray diffraction. The ethylene–propylene rubber (EPR) particle morphology in the TPO underwent progressive particle breakup and decreased in particle size as the clay loading increased from 0.6 to 5.6 wt %. TEM micrographs showed that the clay platelets preferentially segregated to the rubber–particle interface. The breakup of the EPR particles was suspected to be due to the increasing melt viscosity observed as the clay loading increased or to the accompanying chemical modifiers of the clay, acting as interfacial agents and reducing the interfacial tension with a concomitant reduction in the particle size. The flexural modulus of the injection moldings increased monotonically as the clay loading increased. The unnotched (Izod) impact strength was substantially increased or maintained, whereas the notched (Izod) impact strength decreased modestly as the clay loading increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 928–936, 2004     

An Optimizing Compiler for Parallel Chemistry Simulations

Well designed domain specific languages have three important benefits: (1) the easy expression of problems, (2) the application of domain specific optimizations (including parallelization), and (3) dramatic improvements in productivity for their users. In this paper we describe a compiler and parallel runtime system for modeling the complex kinetics of rubber vulcanization and olefin polymerization that achieves all of these goals. The compiler allows the development of a system of ordinary differential equations describing a complex vulcanization reaction or single-site olefin polymerization reaction—a task that used to require months—to be done in hours. A specialized common sub-expression elimination and other algebraic optimizations sufficiently simplify the complex machine generated code to allow it to be compiled—eliminating all but 8.0% of the operations in our largest program and enabling over 60 times faster execution on our largest benchmark codes. The parallel runtime and dynamic load balancing scheme enables fast simulations of the model.     

Some Thermodynamic Aspects of the Oxides of Chromium

To understand Cr emissions from slag melts to a vapor phase, an assessment of the stabilities of the chromium oxides at high temperatures has been carried out. The objective of the present study is to present a set of consistent data corresponding to the thermodynamic properties of the oxides of chromium, with special reference to the emission of hexavalent chromium from slags. In the current work, critical analysis of the experimental data available and a third analysis in the case of Cr₂O₃ have been carried out. Commercial databases, Fact Sage and ThermoCalc along with NIST-JANAF Thermochemical Tables, have been used for the analysis and comparisons of the results that are presented. The significant discrepancies in the available data have been pointed out. The data from NIST-JANAF Thermochemical Tables have been found to provide a set of consistent data for the various chromium oxides. An Ellingham diagram and the equations for the ΔG° (standard Gibbs free energy change) of formation of CrO _x have been proposed. The present analysis shows that CrO₃(g) is likely to be emitted from slag melts at high oxygen partial pressures.     

Image coding based on maximum entropy partitioning for identifying improbable intensities related to facial expressions

In this paper we investigate information-theoretic image coding techniques that assign longer codes to improbable, imprecise and non-distinct intensities in the image. The variable length coding techniques when applied to cropped facial images of subjects with different facial expressions, highlight the set of low probability intensities that characterize the facial expression such as the creases in the forehead, the widening of the eyes and the opening and closing of the mouth. A new coding scheme based on maximum entropy partitioning is proposed in our work, particularly to identify the improbable intensities related to different emotions. The improbable intensities when used as a mask decode the facial expression correctly, providing an effective platform for future emotion categorization experiments.     

Shotgun protein sequencing by tandem mass spectra assembly

The analysis of mass spectrometry data is still largely based on identification of single MS/MS spectra and does not attempt to make use of the extra information available in multiple MS/MS spectra from partially or completely overlapping peptides. Analysis of MS/MS spectra from multiple overlapping peptides opens up the possibility of assembling MS/MS spectra into entire proteins, similarly to the assembly of overlapping DNA reads into entire genomes. In this paper, we present for the first time a way to detect, score, and interpret overlaps between uninterpreted MS/MS spectra in an attempt to sequence entire proteins rather than individual peptides. We show that this approach not only extends the length of reconstructed amino acid sequences but also dramatically improves the quality of de novo peptide sequencing, even for low mass accuracy MS/MS data.     

Ultraviolet absorption spectra: Some substituted benzoic acids

The u.v. absorption spectra of 22 monosubstituted and 19 disubstituted benzoic acids have been studied in water or aqueous dioxan over a pH range of about 1–8. The isosbestic points have been measured and the results are discussed.     

Ultraviolet absorption spectra: Some substituted coumarins

The u.v. absorption spectra of forty-one substituted coumarins have been studied in methanol and aqueous methanol over a pH range. The effect of the nature and position of the substituent in the coumarin nucleus is discussed.     

Ultra-violet absorption spectra: 4-hydroxy coumarins

The ultra-violet absorption, in the range 250 mμ—350 mμ, of twelve 4-hydroxy coumarins in methanol and in 10% aqueous methanol over a range of pH, has been studied and discussed.     

Antihyperglycemic, antihyperlipidemic, and antioxidant effects of Chaenomeles sinensis fruit extract in streptozotocin-induced diabetic rats

The rising incidence of diabetes mellitus (DM) is alarming and becoming a major health problem worldwide, which is mainly associated with hyperglycemia, abnormal lipid, and antioxidant profiles. Herbal medicines are being used by about 80% of the world population primarily in the developing countries for primary health care, including DM. Based on these facts, in this study, the antihyperglycemic, antihyperlipidemic, and antioxidant properties of Chaenomeles sinensis fruits extract (CSFE) were investigated in streptozotocin (STZ)-induced (55 mg/kg body weight) diabetic rats. CSFE was found to be rich in total phenolics and flavonoid contents. The following assays were performed: fasting blood glucose, hemoglobin (Hb), blood urea nitrogen (BUN), serum total cholesterol (TC), serum triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), serum glutamic pyruvic transaminase/alanine aminotransferase (SGPT/ALT), serum glutamic oxaloacetic transaminase/aspartate aminotransaminase (SGOT/AST), liver glycogen content and superoxide dismutase (SOD), reduced glutathione (GSH), and catalase (CAT) contents in liver and kidney. Oral administration of CSFE (500 mg/kg body weight) significantly decreased fasting blood glucose, BUN, and serum TC, TG, LDL-C, SGPT/ALT, and SGOT/AST, while it increased blood Hb content and HDL-C in diabetic rats. Furthermore, CSFE treatment significantly increased liver glycogen content, SOD, GSH, and CAT levels in diabetic rats. The results showed that CSFE significantly inhibited the progression of diabetes induced by STZ, and the inhibitory effect of CSFE on diabetes might be associated with its hypoglycemic effect, modulation of lipid metabolism, and its ability to scavenge free radicals.