Natural working fluids for solar-boosted heat pumps

The option of using natural working fluids as a substitute of R-22 for solar-boosted heat pumps depends not only upon thermal performance and hazardous rating but also on potential impacts on the environment. This paper presents the comparative assessment of natural working fluids with R-22 in terms of their characteristics and thermophysical properties, and thermal performance. Some justification is given for using natural working fluids in a solar boosted heat pump water heater. The results show that R-744 is not suitable for solar-boosted heat pumps because of its low critical temperature and high operational pressures. On the other hand, R-717 seems to be a more appropriate substitute in terms of operational parameters and overall performance. However, major changes in the heat pumps are required. R-290 and R-1270 are identified as candidates for direct drop-in substitutes for R-22.     

Fluorescent image analysis of lipid hydroperoxides in fish muscle with 3-perylene diphenylphosphine

A fluorescent image analysis method was developed to evaluate lipid hydroperoxide formation in fish muscle. The lipid hydroperoxides generated in white and dark fish muscles during storage at 5–6°C oxidized 3-perylene diphenylphosphine located in the tissue to yield the fluorescent derivative, 3-perylene diphenylphosphine oxide (3-PeDPPO). 3-PeDPPO thus obtained was determined by digital fluorescent image analysis. The 3-PeDPPO fluorescence intensity of white and dark muscle increased during low-temperature storage (0–24 h) and was clearly correlated with total lipid hydroperoxide levels in muscle extracts, which were determined by using HPLC based on a triphenylphosphine oxidation method (R ²=0.954). These results suggest that 3-PeDPPO fluorescence, coupled with fluorescent image analysis, is a novel tool for direct determination of lipid hydroperoxides in fish muscle without a need for extraction of lipid.     

Effect of Ga modification on different pore size silicas in synthesis of LLDPE by copolymerization of ethylene and 1-hexene with [<Emphasis Type="Italic">t</Emphasis>-BuNSiMe<Subscript>2</Subscript>Flu]TiMe<Subscript>2</Subscript>/MMAO catalyst

Copolymerization of ethylene and 1-hexene for obtaining the linear low-density polyethylene was conducted along with silicas as supports for [t-BuNSiMe₂Flu]TiMe₂/MMAO catalyst. Two silicas with different pore sizes were used to investigate the effect of pore sizes on copolymerization. In addition, gallium was also introduced into both silicas to improve their properties and enhance the catalytic activities of the system. It was found that before modification, the larger pore silica exhibited higher catalytic activity than the smaller one due to low internal diffusion resistance. After modification, both silicas exhibited higher catalytic activity comparing to their pristine condition. However, 1-hexene incorporation in the obtained copolymers was lower. The reduced surface area of silica after modification was the main reason for the decrease in 1-hexene incorporation. The properties of the copolymers by means of differential scanning calorimetry, gel permeation chromatography, and ¹³C NMR spectroscopy were further discussed in more detail.     

Invariance and convergent and discriminant validity between mothers' and fathers' ratings of oppositional defiant disorder toward adults, ADHD-HI, ADHD-IN, and academic competence factors within Brazilian, Thai, and American children.

Confirmatory factor analysis was used to test the invariance of an oppositional defiant disorder toward adults, attention-deficit/hyperactivity disorder-hyperactivity/impulsivity, attention-deficit/hyperactivity disorder-inattention, and an Academic Competence factor model between mothers' and fathers' ratings within Brazilian (n = 894), Thai (n = 2,075), and American (n = 817) children with the Child and Adolescent Disruptive Behavior Inventory (G. L. Burns, T. Taylor, & J. Rusby, 2001a, 2001b). The results showed invariance of item loadings, intercepts, and residuals, as well as factor variances, covariances, and means between mothers' and fathers' ratings within each sample. Convergent and discriminant validity was also observed for the between-parent factor correlations, thus providing additional support for the construct validity of the Child and Adolescent Disruptive Behavior Inventory. The confirmatory factor analysis invariance procedure provides a much better way to examine between-source ratings of behavior problems in children than do the simple correlation and raw discrepancy score procedures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparative production of a monoclonal antibody specific for enrofloxacin in a stirred-tank bioreactor

A hybridoma producing monoclonal antibody (MAb) specific for enrofloxacin was cultivated in a 2-L stirred-tank bioreactor in various modes and the performances of each mode were compared. In batch mode, a maximum viable cell and MAb concentration of 9.21 × 10⁵ cells mL^?1 and 67.3 mg L^?1, respectively, were obtained. When the hybridoma was cultivated in a fed-batch culture with the addition of specific nutrients, no improvement in either the viable cell number or MAb concentration was observed. On the other hand, an increase in the production of toxic metabolites, i.e. ammonia and lactate, was observed with growth inhibition of the hybridoma cells occurring at ammonia and lactate concentrations of 2.0 mM and 2.0 g L^?1, respectively. However, the best performance of hybridoma cultivation was achieved in a perfusion culture mode using a spin filter, which was installed in the stirred-tank reactor as a cell retention device with a perfusion rate of 0.80 vvd. Under these conditions a steady viable cell concentration of 1.57 × 10⁶ cells mL^?1 was obtained within five days with an overall productivity and yield of 73.7 mg L^?1 d^?1 and 61.4 mg d^?1, respectively, which was a significant increase over that attained with the batch process.     

Effects of handicraft sitting postures on lower trunk muscle fatigue

Fifteen male subjects were exposed to a primary tracking task and a variety of subsidiary tasks for a total of 15 hours. Tracking performance was assessed through the use of two error measures, amount of time off the target track, and number of times off target. Subsidiary performance tasks included: a vigilance task requiring subjects to respond to the deflection of the noodle of a small meter; two reaction time tasks requiring response to the onset of one or the other of two lights; mental multiplication, which required the solution of simple multiplication problems; and digit span, in which the subject was required to repeat as rapidly and as accurately as possible a sot of digits of either five, six or seven numbers in length. In addition, three physiological measures were obtained.

A significant decrement in trucking performance was obtained for both measures utilized. This decrement was not particularly abrupt in its occurrence but rather took place cumulatively over the entire course of the experiment. There was no clearly established performance decrement on the subsidiary tasks utilized in this investigation. A marked variability in performance over the course of the experimental session was characteristic of performance on these tasks. Performance on the vigilance task, and one of the reaction time tasks improved during the 15-hour test session.

The 17-Kotosteroid and 17-Hydroxyeortieoid values increased during the session but only in the case of the latter was the increase significant. The eosinophil count of subjects exposed to the test conditions decreased steadily throughout the experimental session. However, eosinophil measures obtained from control subjects increased during a similar time period.     

Development of an inventory and temporal allocation profiles of emissions from power plants and industrial facilities in Thailand

An emission inventory (EI) of power plants and industrial (i.e., non-power plant) facilities in Thailand was developed. Emissions considered are those from fuel consumption (i.e., combustion) for power plants and those from both fuel consumption and industrial processes (i.e., non-combustion) for industrial facilities. For power plants, total annual emissions due to fuel consumption are 107.9 x 10(3) ton NOx (as NO2), 146.2 x 10(3) ton SO2, 6.1 x 10(3) ton NMVOC (non-methane volatile organic compounds), 47.0 x 10(3) ton CO, 1.8 x 10(3) ton NH3, 1.5 x 10(3) ton OC (organic carbon), and 1.5 x 10(3) ton BC (black carbon). For industrial facilities, total annual emissions due to fuel consumption are 111.4 x 10(3) ton NOx (as NO2), 476.9 x 10(3) ton SO2, 33.4 x 10(3) ton NMVOC, 193.1 x 10(3) ton CO, 1.6 x 10(3) ton NH3, 8.5 x 10(3) ton OC, and 8.0 x 10(3) ton BC. Among various industrial types, Food and Beverage, Chemical, and Non-Metal industries are dominant emitters. Total annual emissions due to industrial processes are 79.2 x 10(3) ton SO2, 76.0 x 10(3) ton NMVOC, and 4.8 x 10(3) ton CO. The Central and Eastern regions combined contribute considerably to total emissions for most emission species. Emission estimates found here show fair agreement with those in some selected past studies. A crude estimation of potential fugitive NMVOC emissions specifically from petroleum industry was also made, and the estimates found could be considered significant (nearly half of NMVOC emissions from industrial processes). Several temporal allocation profiles of emissions were also developed and suggested for power plants and industrial facilities, including monthly, daily, and hourly profiles.     

Adsorptive removal of thiophene and benzothiophene over zeolites from Mae Moh coal fly ash

Zeolites have been hydrothermally synthesized using Thai coal fly ash from Mae Moh Power Plant as silica and alumina sources. The synthesis conditions, i.e., SiO₂/Al₂O₃ ratio, amount of water, amount of base, and aging temperature, were varied to prepare different topologies of zeolitic products. The zeolites attained were sodalite (SOD), gismondine (GIS), and cancrinite (CAN). The zeolites have been applied to adsorption of thiophene and benzothiophene in n-hexane solution. It was found that GIS with higher specific surface area and average pore volume had superior performance to other synthesized materials. Adsorption capacity of our developed zeolites was compared to those of commercial zeolites, i.e. NaY, HUSY, beta, and ZSM-5 obtained via the conventional synthesis methods. The results suggested a potential of zeolites derived from Mae Moh coal fly ash for removal of refractory sulfur compounds, such as benzothiophene.     

Synthesis of polyethylene/coir dust hybrid filler via in situ polymerization with zirconocene/MAO catalyst for use in natural rubber biocomposites

In This study, polyethylene/coir dust hybrid filler was synthesized by in situ polymerization using a zirconocene/MAO catalytic system. The obtained hybrid filler was then used for the production of natural rubber biocomposites. The synthesis process of the filler was investigated with variation of coir dust loadings. It was found that increasing the amount of coir dust decreased the catalytic activities due to negative supporting effects. After introducing the PE/coir dust hybrid filler into natural rubber, SEM micrographs showed that the PE/coir dust filler were more compatible with the natural rubber matrix than the pure coir dust. This is owing to the hydrophobicity of the polyethylene in the hybrid filler. The results from a dynamic mechanical analysis showed that the natural rubber biocomposites with the hybrid filler provided a greater storage modulus than that with the pure coir dust. This suggests that the enhanced stiffness of the natural rubber biocomposites is probably due to the strong interaction between the hybrid filler and the natural rubber matrix. The strong interaction in the biocomposite can be confirmed by the low value of a loss factor (tan δ), which indicates a low degree of molecular mobility of the polymer chains, resulted from good adhesion on the filler surfaces.