Thermal pretreatment of kudzu biomass (pueraria lobata) as filler in cost‐effective pla biocomposite fabrication process

This article aims on the fabrication of cost‐effective polylactic acid (PLA) biocomposites using kudzu biomass derivatives as new filler. In this way, it has been realized that pretreatment of the filler was an essential requirement. We demonstrated thermal pyrolysis process that targeted to extraction and isolation of all extractable and unnecessary compounds such as intracellular water and bio‐oil from the biomass. Also, to further improve the compatibility of the filler with PLA, noncatalytic thermal esterification reactions of kudzu after thermal pyrolysis (called char) were carried out as second pretreatment stage in the presence of phthalic anhydride. Kudzu derivatives obtained from either first or second pretreatment reactions were melt‐blended with PLA in various rates. The blends were then compression molded into dumbbell specimens. Physicomechanical properties of the prepared biocomposites were evaluated using several analytical techniques. It was found that biocomposites containing treated biomass had higher values of physicomechanical properties than untreated ones. The final rate of filler to PLA with acceptable properties was set up to 50%. Obviously, the cost of PLA can be reduced using higher rates of low‐cost filler on a finished‐product basis. Extracted valuable compounds from biomass via thermal pyrolysis could be another benefit of the process. POLYM. ENG. SCI., 55:340–348, 2015. © 2014 Society of Plastics Engineers     

Thermally decomposable phosphonate ester polymer gels

A polymerizable dimethacryloyl vinylphosphonate (DMVP) was developed as a novel crosslinking agent by esterification of vinylphosphonic acid and methacryloyl chloride in the presence of triethylamine. Then, poly(DMVP) (PDMVP) was generated by bulk polymerization solution at 30, 45, and 80 °C in the presence of a radical initiator. The resultant PDMVP, polymerized at 45 and 80 °C, could be dissolved in acetone, water, and N-methylpyrrolidone. However, PDMVP obtained at 30 °C showed to be insoluble in such solvents and became a gel instead. It was found that the formed gel was soluble when heating due to hydrolysis of the ester bonds in the polymer. Evidence was presented showing the thermal decomposition behavior of the PDMVP gel, which showed an irreversible solid-to-liquid phase transition.     

Doping effect of divalent cations on sintering of polycrystalline yttria

The sintering behavior of Y₂O₃ doped with 1 mol% of Ca²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Sr²⁺ or Zn²⁺ was investigated by pressureless sintering in air at a sintering temperature in the range 900–1600 °C. The sintering temperature required for full densification in Y₂O₃ was reduced by 100–400 °C by the cation doping, while undoped Y₂O₃ was densified at 1600 °C. The most effective dopant among the examined cations was Zn²⁺. The grain growth kinetics of undoped and cation-doped Y₂O₃ was described by the parabolic law. The grain boundary mobility of Y₂O₃ was accelerated by doping of the divalent cations. High-resolution transmission electron microscopy (HRTEM) observations and nano-probe X-ray energy dispersive spectroscopy (EDS) analyses confirmed that the dopant cations tended to segregate along the grain boundaries without forming amorphous layers. The improved sinterability of Y₂O₃ is probably related to the accelerated grain boundary diffusion owing to the grain boundary segregation of the dopant cations.     

Organic dyes with oligo-n-hexylthiophene for dye-sensitized solar cells: Relation between chemical structure of donor and photovoltaic performance

Organic dyes with the oligohexylthiophene linkage having several donor parts, carbazole, indole, and indoline, were newly synthesized as sensitizers for dye-sensitized solar cells. The carbazole was most efficient donor moiety for DSSCs among these dyes with the oligothiophene linkage. Carbazole dyes were adsorbed with larger amount of molecules on the TiO₂ film than both indole dyes and indoline dyes. Therefore, both the V_OC and the electron lifetime of DSSCs with the carbazole dyes were highly observed. The decreasing of J_SC of DSSCs with indole and indoline dyes also caused by the reducing the adsorption amount of dyes.     

Aspects of voltage responses of induction motor loads

In this paper, the voltage dynamics of induction motor loads up to some ten seconds are discussed in terms of a linearized model. It is generally recognized that the dynamics of a power system load mainly originate from the induction motor dynamics constituting the load. Aspects of the voltage dynamics of induction motors are analyzed with respect to machine constants. The results show that small and medium-sized induction motors have dynamics that can be well approximated at the first order, thus partly accounting for the fact that most feeders indicate first-order dynamics     

EFFECT OF CALCIUM ALGINATE COATING ON THE PERFORMANCE OF IMMOBILIZED YEAST CELLS IN CALCIUM ALGINATE BEADS

A cell immobilization technique to prevent cell leakage from the matrix in a very common system, alginate-Saccharomyces cerevisiae, was investigated. A double coating of immobilized cell beads prevented leakage very well in flask fermentation even when shaking was applied. The suitable concentrations of sodium alginate were 5, 5 and 3 wt% for the core, internal coating and external coating, respectively. The suitable concentration of calcium chloride was 1 wt% for all cases. Fermentation using a fixed bed reactor containing the immobilized cells was carried out successfully for 25 d.     

Diosgenin present in fenugreek improves glucose metabolism by promoting adipocyte differentiation and inhibiting inflammation in adipose tissues

In obesity, adipocyte hypertrophy and chronic inflammation in adipose tissues cause insulin resistance and type‐2 diabetes. Trigonella foenum‐graecum (fenugreek) can ameliorate hyperglycemia and diabetes. However, the effects of fenugreek on adipocyte size and inflammation in adipose tissues have not been demonstrated. In this study, we determined the effects of fenugreek on adipocyte size and inflammation in adipose tissues in diabetic obese KK‐Ay mice, and identified the active substance in fenugreek. Treatment of KK‐Ay mice with a high fat diet supplemented with 2% fenugreek ameliorated diabetes. Moreover, fenugreek miniaturized the adipocytes and increased the mRNA expression levels of differentiation‐related genes in adipose tissues. Fenugreek also inhibited macrophage infiltration into adipose tissues and decreased the mRNA expression levels of inflammatory genes. In addition, we identified diosgenin, a major aglycone of saponins in fenugreek to promote adipocyte differentiation and to inhibit expressions of several molecular candidates associated with inflammation in 3T3‐L1 cells. These results suggest that fenugreek ameliorated diabetes by promoting adipocyte differentiation and inhibiting inflammation in adipose tissues, and its effects are mediated by diosgenin. Fenugreek containing diosgenin may be useful for ameliorating the glucose metabolic disorder associated with obesity.     

First-Principles Study of Semiconducting Clathrate Ba<Subscript>8</Subscript>Al<Subscript>16</Subscript>Ge<Subscript>30</Subscript>

We calculated electronic structures of Ba₈Al₁₆Ge₃₀ in some Al-Ge framework configurations without nearest-neighbor Al-Al bonds by using a first-principles method. The calculated band structures are similar in outline but different in detail. We also calculated thermoelectric properties by using the electronic structures to analyze the experimental results on a sintered Ba₈Al₁₆Ge₃₀ sample. The calculated properties nearly agree with the experimental results; however, the calculated temperature dependences of electrical conductivity are slightly different from one another, because of differences in electronic structure. In this paper, we discuss the temperature dependence from the viewpoints of nonparabolic band effects.