A Preliminary Experiment of Non-Catalytic Transesterification: Thermal Analysis of Palm Oil and Biodiesel at Different Ratio

Currently, the biodiesel production technology is moving toward the trend of non-catalytic reaction under subcritical condition as the conventional non-catalytic transesterification requires high energy input and high production cost. Hence, non-catalytic biodiesel production under subcritical condition using microwave energy is proposed. Before that, thermogravimetric analysis (TGA) was conducted to characterize the biodiesel feedstock and determine the suitable experimental temperature range for the proposed method. Besides, the thermal behavior of the palm oil and biodiesel at different stages of reaction was also investigated. The results showed that the palm oil and biodiesel were started to degrade from 335ºC and 160ºC respectively. However, the degradation point of palm oil was higher than the supercritical temperature of DMC. So, external energy is needed to bring down the operating condition, such as microwave energy as it has potential to reduce the activation energy. To further eliminate the problem of biodiesel thermal degradation during the transesterification process, the suggested experimental temperature range is within 80ºC to 180ºC, which is from the temperature lower than the boiling point of DMC (<90ºC) to the temperature slightly higher than the biodiesel thermal degradation point. Furthermore, DSC result indicated that palm oil requires 518.35kJ/mol to decompose.

Evaluation of Chlorine for Inactivation of Bioterrorism Agents in Drinking Water

The object of this paper is to measure the characteristics of the inactivation kinetics of B. subtilis spores-surrogates for B. anthracis spores following the treatment with free chlorine. The results indicated that the inactivation kinetics of B. subtilis spores with free chlorine was characterized by a lag phase followed by a pseudo-first-order rate of inactivation. The magnitude of the lag phase increased and the rate of subsequent inactivation decreased with the decreasing temperature, for the experimental temperature range of 1-30 °C. The same tendency of inactivation kinetics curves was observed for the increasing solution pH, for the experimental pH range of 6-8. The CT concept was proved to be valid for the inactivation kinetics of B. subtilis spores with free chlorine under the conditions investigated. The validity of B. subtilis spores served as conservative surrogates for B. anthracis spore has been finally discussed.

High-Temperature Performance of 1200 V, 200 A 4H-SiC Power DMOSFETs

We have investigated the thermal behavior of our recently developed 1200 V, 200 A 4H-SiC power DMOSFETs operating from 20°C up to 300°C. Compared to the first generation SiC DMOSFET that was commercially released early this year, this 4H-SiC power DMOSFET shows a ~ 50% reduction in the total specific on-resistance at room temperature. Temperature dependence of the key parameters of this MOSFET, such as on-resistance, threshold voltage, and the MOS channel mobility, are reported in this paper. The MOSFET showed normally-off characteristics throughout the entire experimental temperature range. Different temperature dependence of the total on-resistance in different temperature regimes has been observed.

Gas Pressure Forming of Amorphous Fe78Si9B13 Alloy

The deformation behavior of gas pressure forming of amorphous Fe78Si9B13 alloy was investigated under equibiaxial tension. The gas pressure forming was carried out in the temperature range of 430°C~530°C below the crystallization temperature Tx and die apertures of 5mm~10mm. The dome height and amorphous ribbon thickness of deformed specimens at the pole was measured. It was found that amorphous Fe78Si9B13 alloy had exhibited good plasticity in the experimental temperature range. The near-semisphere specimens of the radius 5mm and the height 4.5mm were obtained from the gas-pressure forming at 450°C and 530°C for 30min, which is similar to the superplastic forming.

An isokinetic relationship in the oxidation of acetals by ozone. Evidence for rotation before the oxidation of acyclic acetals

Second order rate constants for the oxidation by ozone of several acyclic acetals of heptaldehyde were determined at several temperatures. An isokinetic relationship is shown to exist for this series of reactions and the isokinetic temperature was found to be below the experimental temperature range, a domain of temperatures where reactivity is dominated by entropy factors. These results are contrasted with those obtained for cyclic acetals of heptaldehyde, where the isokinetic temperature falls above the working temperatures, a domain of temperatures where reactivity depends mainly on enthalpy factors. These results are interpreted in terms of a conformational change before oxidation in the acyclic acetals.

A comparison of two empirical pKa(T) equations from 298 to 448 K for 2,9-Dimethyl-1,10-phenanthroline

The two most commonly used three-term equation1,2 describing the variation of pKa with temperature are compared over the range 298-448 K for 2,9-dimethyl-1,10-phenanthroline. Both equations represent the data equally well over the experimental temperature range. First-difference calculations and the Σ-plot method are used to fit the data.

Metal complexes of 1,10-phenanthroline derivatives. X. 5T2 ↔ 1A1 transitions in iron(II) complexes of 2-(1,10-Phenanthrolin-2-yl)imidazole derivatives

The preparation of the tridentate chelating agents 2-(1,10- phenanthrolin-2-yl)imidazoline and 2-(1,10-phenanthrolin-2- yl)benzimidazole and their bis-ligand complexes with iron(II) and nickel(II) is described. The latter ligand coordinates as either a neutral or anionic tridentate. Data from the spectra of the nickel(II) complexes indicate that the ligands have field strengths in the iron(II) crossover region. The temperature dependence of the magnetism of the imidazoline iron(II) complex reveals a gradual, temperature- induced 5T2 ↔ 1A1 transition which is not complete within the experimental temperature range (83-363 K). Both the cationic and neutral iron(II) complexes of the benzimidazole derivative are essentially low-spin at room temperature but a significant increase in their magnetic moments at elevated temperatures indicates that a spin transition may be occurring in these compounds too.

Metal complexes of 1,10-phenanthroline derivatives. IX. 5T2 ↔ 1A1 spin transitions in iron(II) complexes of 2-(1,10-phenanthrolin-2-yl)thiazole derivatives

The preparation of the tridentate chelating agents 2-(1,10- phenanthrolin-2-yl)thiazole, 2-(1,10-phenanthrolin-2-yl)-4-(2- pyridyl)thiazole 2-(1,10-phenanthrolin-2-yl)thiazolidine and 2-(1,10- phenanthrolin-2-yl)benzothiazole is described. Data from the spectra of the bis-ligand nickel complexes indicate that the ligands all have field strengths in the iron(II) crossover region. The temperature dependence of the magnetism of the bis-ligand iron(II) complexes reveals that, except for the complexes of the pyridylthiazole, a smooth, temperature-induced 5T2 ↔ 1A1 transition occurs in these compounds. For no complex is the transition complete within the experimental temperature range (83-363 K). The complex of the pyridylthiazole is high-spin throughout the range, the uncoordinated pyridyl group hindering the close approach of ligand and metal atom necessary for spin-pairing. The ability of the other ligands to induce a spin transition is primarily a consequence of distortions in the environment about the metal atom arising from coordination of the five- membered thiazole or related ring.

Metal complexes of 1,10-Phenanthroline derivatives. VII. Complexes of 1,10-Phenanthroline-2-carbaldehyde hydrazones

A series of substituted hydrazones derived from 1,l0-phenanthroline-2-carbaldehyde and their bis-ligand complexes with bivalent iron and nickel are described. The hydrazones show a gradation in field strength and this is reflected in the spin-state of the iron complexes. The methylhydrazone complex is essentially low-spin over the temperature range 83-363 K but the presence of some spin-free species at high temperatures is evident. Within the same range the dimethylhydrazone complex is essentially high-spin but undergoes significant spin-pairing and the phenylhydrazone complex displays a complete 5T2 → 1A1 spin transition. This transition is very sharp, resulting in a pronounced change in the magnetism, and colour, of the complex within a few degrees. Complexes of the 2-pyridylhydrazone, the methylphenylhydrazone and the diphenylhydrazone are high-spin over the entire experimental temperature range.