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  • Author or Editor: Y. Chang x
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Abstract  

Diphenylcarbonate (DPC) has been regarded as a potential substitute material for highly toxic phosgene, reacting with bisphenol A (BPA) in a phosgene-free process to produce polycarbonate (PC). For synthesizing DPC, methylphenylcarbonate (MPC) was the critical intermediate with potential flammability in a transesterification reaction from dimethylcarbonate (DMC) and phenol. Under the National Fire Protection Association (NFPA) criterion, MPC is viewed as one sort of combustible liquid (Class IIIB). Once it fires or burns during storage, operation or transportation, it can cause a serious fire and explosion. However, researches are still scanty in mentioning the basic but crucial fire and explosion features of MPC to date. A sound background of material safety properties is essential for safe handling; in particular, flammability information is extremely crucial for a specific chemical during a unit operation to prevent any fire and explosion hazards. In this study, we investigated the explosion limits (LEL, UEL), maximum explosion pressure (P max), maximum rate of explosion pressure rise ((dP/dt)max), and gas or vapor explosion constant (K g) of MPC, according to its practical operating conditions (1 atm, 250°C, 21 vol.% O2) and by means of a 20 L vessel (20-L-Apparatus). By surveying and defining the experimental data through flammability tests, these basic but crucial safety-related parameters on flammability characteristics of MPC were proposed, so as to advance understanding and to avoid fire and explosion accidents for such relevant processes.

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Abstract  

The purpose of this paper is to study necessary and sufficient conditions for the Ishikawa iterative sequence with mixed errors of asymptotically quasi-nonexpansive type mappings in Banach spaces to converge to a fixed point in Banach spaces. The results presented in this paper complememt, improve and prefect the corresponding results of [1]–[4] and [7]–[9].

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Abstract  

Samples of blood from adults in good health in Taiwan have been analyzed for their137Cs content by gross beta counting using a low background gas-flow counter. The level of137Cs content in blood was 8.3+6.3x10–3 pCi.ml–1 for ages 24+7 y. The deposition of fission product137Cs in Taiwan, which was monitored by water tray for fallout, was also studied since January 1979.

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Abstract  

The isotope fractionation of potassium in an aqueous (KOH)/amalgam system has been studied. Two types of isotope effects with opposite isotope enrichment directions were observed in the electrolysis of potassium from the aqueous into the amalgam phase under constant electrolytic potentials. It was found that the first isotope effect causing the light isotope enriched in the amalgam is related to the kinetic process of the mass transfer through the aqueous/amalgam interface, while the second one leading to the enrichment of the heavy isotope in the amalgam phase is produced by the isotope-exchange equilibrium. The temperature dependence of the equilibrium isotope effect was also investigated using single-stage and multi-stage techniques. It was observed that the equilibrium isotope effect increases as the temperature increases in the range of 293-371 K. An empirical equation was used to fit the variations of the isotope effects with temperature for potassium together with the other alkaline and alkaline earth metals studied in the same system. The origin of the equilibrium isotope fractionation in the electron-exchange system was discussed. Furthermore, the mass dependence of the separation coefficients of the alkaline and alkaline earth metals observed in aqueous/amalgam and ion-exchange systems were compared. At 293 K the equilibrium isotope separation coefficient for the 39K/41K isotopes in the amalgam system was determined as (5.6±0.6).10-3.

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Abstract

The primary aim of this study was to investigate the influence of emotional expression and dynamic information on attractiveness judgements of male and female targets. 56 undergraduate participants were presented with video and static stimuli in smiling and neutral conditions (40 targets, 160 stimuli). Our results indicate that smiling and movement influence attractiveness judgements differentially for male and female targets. Smiling increases the attractiveness ratings of female, but not male targets, whereas movement increases the attractiveness ratings of male, but not female targets. Secondly, and perhaps most importantly, our findings demonstrate that the evaluative standards used by raters differ across presentation conditions. Although ratings of women's faces are positively related across movement and expression conditions, attractiveness ratings of smiling and neutral men's faces are correlated within movement conditions, but not across them. These findings highlight the importance of studying faces in motion to determine the factors influencing interpersonal attraction, and caution against the overgeneralization of results from research using static faces.

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In bread making the wheat dough undergoes some degree of deformation in each step of the process. It is generally accepted that the baking properties of wheat flour dough are mainly due to the viscoelasticity of the gluten protein. Measurement of the rheological properties of dough gives valuable information concerning the quality of the wheat flour, the machining properties of the dough and the textural characteristics of the finished products. This technique uses a new apparatus (wheat gluten quality analyser&WGQA, C HANG, 1994) especially developed to evaluate the rheological properties of gluten by measuring the following parameters: resistance to extension (newton), extensibility (mm) and energy (joule). The test realized with the apparatus WGQA was carried out on wheat gluten isolated according to the A.A.C.C. (1995) method. Results obtained using the new technique showed high levels of correlation for maximum resistance to extension (R 2 =0.9018) and energy (R 2 =0.8824) between WGQA and standardized parameters obtained from Brabender Extensograph.

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Single screw extrusion of cassava starch was evaluated as a pre-treatment for the enzymatic hydrolysis of the extrudate and fermentation to yield alcohol. The acid concentration, barrel temperature and moisture content showed that all the variables were significant. Increasing acid concentration or barrel temperature induced starch depolymerisation with a higher water solubility index and lower water absorption index. At 20 and 24% moisture contents the cold paste viscosity decreased. As a result of the addition of acid during extrusion cooking the degree of starch hydrolysis resulted in low hot paste viscosity. Acid concentration was significant in the production of reducing sugars. At concentrations above 0.024 N, as the temperature increased, the reducing sugar content also increased. Nevertheless, at concentrations below 0.024 N, the reducing sugar content showed the opposite result. The best yield of alcohol obtained from the extruded starch was 98.7% (0.56 g of ethanol/g starch), which, on average, was 5.7% and 6.8% higher than that obtained from starch extruded without acid and from starch gelatinized by the conventional method, respectively.

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Abstract

Convergence in Mallows distance is of particular interest when heavy-tailed distributions are considered. For 1≦α<2, it constitutes an alternative technique to derive central limit type theorems for non-Gaussian α-stable laws. In this note, we further explore the connection between Mallows distance and convergence in distribution. Conditions for their equivalence are presented.

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Abstract  

The newly manufactured N-isopropylacrylamide (NIPAM) polymer gel is composed of four components, i.e., gelatin, monomer (NIPAM), crosslinker (N,N’-methylenebisacrylamide, Bis), and antioxidant (tetrakis hydroxymethyl phosphonium chloride, THPC). In this study, we investigated the effects of gel composition on the dose response of NIPAM polymer gel. A statistical experiment to analyze the contribution of each composition to the linearity and sensitivity of NIPAM gel was performed. Results indicate that the amount of gelatin, NIPAM (15.17%), Bis, and THPC have dominant effects on the sensitivity of the gel, with contributions of 59.73, 15.17, 10.64, and 14.45%, respectively. The amount of gelatin and Bis mainly affected the linearity of the gel, with contributions of 44.70 and 50.99%, respectively. The linearity of most compositions of the gel was greater than 0.99 when (%C)/(%T) was lower than 8.0. Optimal (%C)/(%T) for higher sensitivity should be in the range of 4−9. The temporal stability experiment showed that the dose response curve attained stability at about 5 h after irradiation and persisted up to 3 months.

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Abstract  

Flammable chemicals are frequently encountered in industrial processes. Under the safe operation basis and for fire/explosion danger prevention, it is imperative to recognize the flammability characteristics of these processes, especially under the working scenarios for elevated pressure and temperature. This study was conducted to investigate fire and explosion properties, including the explosion limits (LEL and UEL), maximum explosion overpressure (P max), maximum rate of explosion pressure rise (dP/dt)max, gas or vapor deflagration index (K g) and explosion class (St) of various acetone/water solutions (100, 75, 50 and 25 vol.%) at higher initial pressure/temperature up to 2 atm and 200°C via a 20-L-Apparatus. We further discussed the safety-related parameters and fire/explosion damage degree variations in the above aqueous acetone within 1 atm and 150°C. The results offered a successful solution for evaluating the flammability hazard effect in such a relevant crucial process with elevated pressure and temperature.

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