Effect of filler dispersion degree on the Joule heating stimulated recovery behaviour of nanocomposites

Composites based on highly branched ethylene-1-octene copolymer (EOC) and carbon black (CB) with different dispersion degree of CB were prepared. The method of the online measured electrical conductance/resistance was used to monitor the change of the electrical conductance/resistance of the composites during the preparation processes, i.e. mixing and cross-linking. It was found that the kinetics of thermally stimulated shape-memory recovery of CB filled EOC is strongly influenced by the filler dispersion degree, which actually affects the heat transfer in the composites. Using a special arrangement of experiments the Joule heating stimulated shape-memory behaviour was quantified. CB dispersion degree and related electrical resistivity determine the extent of the Joule heating stimulated shape-memory behaviour. Composite collected at the maximum in the online measured conductance–time characteristics showed the best shape-memory effect owing to the highest electrical conductivity in the solid state. The CB filled EOC showed a negative thermal coefficient of resistivity (NTC) effect, which accelerates the temperature increase and shape-memory recovery of the composites when applying a voltage.     

Kooroo color: 90-day dietary toxicity study in F344 rats

A subchronic toxicity study on kooroo color was conducted using F344 rats of both genders. Kooroo color is an extract of yam root, Dioscorea matudai Hayata, of which the major components are known to be flavonoid pigments. Use of kooroo as a food color is permitted by the Food Sanitation Law in Japan, but the chronic toxicity has not been evaluated in the literature. Rats were fed the product of kooroo color (PKC) at doses of 0.5%, 1.50%, and 5.0% in basal powder diet, while control groups received PKC-free basal diet, for ninety days. A vehicle control given propylene glycol (PG) alone, at the same dosage that the 5.0% group received, was included, because PKC used in this study contained ca. 80 percent PG, used as an extractant during the manufacturing processes. Daily observation of general behavior, and weekly measurement of body weight as well as food consumption were performed. Hematological, serum biochemical and anatomopathological examinations were conducted at the end of administration. No abnormalities ascribable to the treatment with PKC or PG were noted in any examination in this study. Hence, dietary intake of 5.0% of PKC, i.e., 2,993 mg/kg/day for males, and 3,376 mg/kg/day for females, as a mean daily intake for 90 days, had no observable adverse effect in F344 rats. Therefore, kooroo color has no significant general toxicity, and its toxicity, if any, is of a very low order.     

Syngas production from methane dry reforming over SmCoO3 perovskite catalyst: Kinetics and mechanistic studies

The kinetics of the methane dry (CO₂) reforming over the SmCoO₃ was investigated in the temperature ranged 973–1073 K by varying the CH₄ and CO₂ partial pressures. Based on detailed study of the reaction mechanism, a mechanistic model is proposed from which a kinetic model is derived. The mechanistic pattern assumes adsorption of CH₄ on reduced Co, followed by methane cracking and carbon deposition. CO₂ reacts with Sm₂O₃ to form Sm₂O₂CO₃ and the oxycarbonates react with carbon to produce CO. The power law and Langmuir–Hinshelwood kinetic model which is established on this mechanism were able to forecast the kinetic results.     

Single-chamber filament-assisted chemical vapor deposition of polymer and organosilicate films for air gap interconnect formation

Air gaps introduced at the trench level of advanced interconnects provide a means of lowering effective dielectric constant, k_eff, without the use of mechanically weak ultra low-k films. Filament-assisted chemical vapor deposition (FACVD) is a promising technology for depositing polymers, dielectrics and metals. Initiated chemical vapor deposition (iCVD) is a novel one-step method of depositing polymers in the vapor phase while retaining properties found in solution chemistry. In this paper, we present a 300 mm FACVD tool employing iCVD and FACVD processes to deposit polymer adhesion promoter (AP), decomposable polymer (DP), and permeable SiCOH cap films for air gap integration. By decomposing the iCVD polymer to form voids, we show decreased capacitance for a 160 nm line-space single damascene structure.     

Influence of carbon black properties on the Joule heating stimulated shape‐memory behavior of filledethylene‐1‐octene copolymer

The shape‐memory (SM) behavior of ethylene‐1‐octene copolymer (EOC) reinforced by carbon black (CB) was investigated. Two CB types, N110 and EC600, with different structure and specific surface area were used as conductive fillers. The mechanical tests showed that on addition of CB into EOC, modulus and strength increased significantly for both CB types but the elastic behavior stands on. The electrical resistivity decreases drastically with increasing CB content. The thermally stimulated SM recovery is deteriorated significantly because of the rigid CB network formed in EOC. With increasing temperature, the CB network gradually loses its rigidity, as the glassy polymer layers connecting the CB aggregates become softened. As a result, the samples with high CB content could recover nearly 100%. In this work, a sample preparation and a corresponding arrangement of experiment were introduced, which allows to quantify the Joule heating stimulated recovery behavior. EOC containing 17 wt% CB EC600 reaches a low resistivity of 8 Ω cm and shows good Joule heating stimulated SM recovery of up to 97% at a voltage of 15 V. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Gymnema sylvestre leaf extract: a 52-week dietary toxicity study in Wistar rats

A 52-week study of oral-repeated-dose toxicity for the extraction powder of Gymnema sylvestre (GS), Indian-native genus, Metaplexis japonica, was conducted in both genders of Wistar rats. The rats were administered a graded dose of GS at 0.01, 0.10 and 1.00% of basal powder diet, along with a group fed solely with the basal powder diet without GS, for 52 weeks. General conditions were recorded daily. Body weights and food consumptions were recorded weekly up to 12 weeks, and thereafter at longer intervals. At 26 weeks, for an intermediate examination, and 52 weeks, for the final examination, animals were subjected to hematology, serum chemistry, and pathological examination. None of the animals died in the period up to 52 weeks. No exposure-related changes in body-weight, in the food consumption, in the hematological examinations, or in the serum biochemical examinations were recognized. No histopathological alterations were seen. Thus, it was concluded that there was no toxic effect in rats treated with GS at up to 1.00% in the diet for 52 weeks. The no-observable-effect level from this study is 1.00% GS, i.e., 504 mg/kg/day for male and 563 mg/kg/day for female as mean daily intake, for 52 weeks.     

The role of catalyst synthesis on the enhancement of nickel praseodymium (III) oxide for the conversion of greenhouse gases to syngas

Clean Technologies and Environmental Policy - Catalytic methane (CH4) dry reforming (MDR) reaction proceeds with the formation of carbon; hence the effects of the catalyst preparation method on the...