Mixture

Translations are often applied on equations of state with the aim of improving the description of molar volumes. In the present note an alternative presentation of the ideas developed in the pioneering work of Ptneloux and Rauzy [PCneloux, A., E. Rauzy, A consistent correction for Redlich-Kwong-Soave volumes. Fluid Phase Equilib., 8 (1982) 7-23.1 is provided and some issues are discussed in a deeper level of detail. 0 1997 Elsevier Science B.V. Key~~wds: Model; Equation of state; Volume; Vapor pressure; Mixture: Translations * Corresponding author 0378.3812/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. /'II s037x-~x12(97)00185-4

This work investigated the shear and uniaxial extensional flow behaviour of aqueous casein and phosphated waxy maize starch systems as a function of the deformation rate, biopolymer concentration and the temperature. Trouton ratios were calculated to compare different responses of biopolymers to the shear and extensional deformation. It was found that the casein system (20% w/w) had a much higher and linearly increasing Trouton ratio against the log increase of strain rate. The starch system (35% w/w) had a Trouton ratio close to 3 at low strain rates, but increasing linearly once the strain rate exceeded 2 s À1 . The apparent shear and extensional viscosity showed an exponential increase with the concentration for both biopolymers, with casein being more concentration dependent. Their Trouton ratios were also very much concentration dependent: remained close to 3 at low biopolymer levels, but increased significantly at higher concentrations. Temperature variation experiments demonstrated that the flow properties of casein and waxy maize starch follow an Arrhenius relationship, with casein showing stronger temperature dependence than starch. While casein systems displayed a decrease in Trouton ratio with temperature increase, waxy maize starch had the opposite behaviour. The mixing of casein-waxy maize starch resulted in higher apparent extensional viscosities and higher Trouton ratios than single biopolymer systems. r

Glass transition temperatures were determined for dehydrated lactose/salt mixtures with various water contents and water activities, and state diagrams were established. Crystallization behaviour was studied for pure amorphous lactose stored at various relative water vapour pressures (RVP). Furthermore, glass transitions temperatures and time-dependent lactose crystallization of freeze-dried lactose and lactose/CaCl 2 , lactose/NaCl, lactose/MgCl 2 and lactose/KCl mixtures in molar ratios of 9:1 were determined. Glass transition temperatures (T g) of lactose powder as determined by differential scanning calorimetry (DSC) was lower than that of lactose/CaCl 2 (9:1) , and lactose/MgCl 2 (9:1), but it was slightly higher than the T g of lactose/NaCl (9:1), and lactose/KCl (9:1). Lactose/KCl had the lowest glass transition temperature, but it had about the same crystallization temperature as lactose/NaCl, and lactose/MgCl 2. The glass transition temperatures decreased as water contents increased. The critical water contents and water activities at 23 1C were predicted using data on glass transition temperature and water sorption. Pure lactose had a different critical water activity and water content from lactose/salt mixtures. The critical values of lactose/CaCl 2 (9:1) were the highest. Loss of sorbed water, indicating lactose crystallization, was observed in lactose and lactose/salt mixtures stored above the critical RVP.

The crystallization behavior of poly(pheny1ene sulfide) (PPS) has been examined by differential scanning calorimetry as a function of melt temperature, residence time in the melt, and the presence of a liquid crystal polymer. The results suggest that the thermal history of the sample plays an important role in determining the crystallization kinetics. Short residence times at low melt temperatures and high melt temperatures alone resulted in a low value for the Avrami exponent n. The former effect was ascribed to incomplete melting of the polymer while the latter effect was attributed to thermal degradation. Blending a liquid crystal polymer, Vectra A950, with PPS had only a minor effect on the crystallization behavior.

Objective Fetal nuchal translucency (NT) thickness increases with crown-rump length (CRL). In screening for chromosomal defects patient-specific risks are derived by multiplying the a priori maternal age-related risk by a likelihood ratio, determined from the deviation of the measured NT from the expected median. To quantify this deviation the measured NT is either subtracted (delta NT) or divided by the expected median (multiple of the median method, MoM). This study examines the validity of these methods. Methods NT was prospectively measured at 11 + 0 to 13 + 6 weeks in screening for chromosomal defects. The distribution of NT in euploid and chromosomally abnormal fetuses was examined.

Progesterone rapidly dissolves in an aqueous solution containing hydroxypropyl-b-cyclodextrin (HPBCD) at 1:2 molar ratio, forming a soluble inclusion complex. After filtration and freeze-drying of the final solution, the final powder was examined by SEM, DSC, TGA, XRD, Raman, and FTIR spectroscopy. Experimental results confirm that an inclusion complex exists in the solid state and possible structure of the complex is briefly discussed. ß

Phenols and plasticizers are widely used in the plastic industry, in food packaging and to impart softness and flexibility to normally rigid plastic medical devices and children's toys. The effects on the aryl hydrocarbon receptor (AhR) and the androgen receptor (AR) were assessed using luciferase reporter gene assays of the following compounds: bisphenol A (BPA), 4-n-nonylphenol (nNP), 4-tert-octylphenol (tOP), bis(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP), diisodecyl phthalate (DIDP), di-n-octyl phthalate (DNOP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), 4-chloro-3-methylphenol (CMP), 2-phenylphenol (2-PP), 2,4-dichlorophenol (DCP), resorcinol and bis(2-ethylhexyl) adipate (DEHA). Furthermore, a mixture of selected compounds was tested at the no-observed-effect concentration (NOEC), the low-observed-effect concentration (LOEC) and the half-maximum-effect/inhibitory concentration (EC 50 /IC 50 ) of the single chemicals.

High-resolution gas chromatography/mass spectrometry (HRGC/MS) is the standard method for analysing dioxin, furan and polybrominated retardants in hazardous waste. Determination of dioxin-like compounds using in vitro bioassays such as ethoxyresorufin-O-deethylase (EROD) is an important tool to evaluate their Ah receptor-mediated toxic effects, because it detects all arylhydrocarbon receptor ligands in a variety of sample matrices. In the present work, we compared RTG-2 cell line EROD bioassay with HRGC/MS for assessing waste samples (liquid and solid) contaminated with polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls (dioxin-like PCBs) and other xenobiotics. For liquid samples, HRGC/MS-toxic equivalent (HRGC/MS-TEQ) values ranged from 273.26 to 5.84 ng TEQ l -1 and correlated well (correlation coefficient 0.99) with values obtained by EROD-TEQ, which ranged from 128 to 2.5 ng TEQ l -1 . For solid samples, HRGC/MS-TEQ values ranged from 3.44 to 0.49 ng TEQ g -1 and correlated less well than liquid samples (correlation coefficient 0.64) with values obtained by EROD-TEQ ranging from 2.27 to 0.93 ng TEQ g -1 . The overestimation of RTG-2 EROD-TEQ (1.2 Ϯ 0.92 of values established by HRGC/MS) and the absence of false-negative results may limit analytical costs by eliminating the need for follow-up GC/MS analysis on the negative samples. We suggest that RTG-2 EROD bioassay is an inexpensive means for preliminary dioxin and furan positive screenings of waste samples.

Binary blend films from lactide-rich poly (D-lactide-co-glycolide) (PDLG) and poly ( Llactide-co-glycolide) (PLLG ) were obtained by casting methylene chloride solutions of the two mixed copolymers with different D-and L-lactide contents ( X D I and X L I ) ,

The solid-liquid equilibrium diagrams of binary mixtures involving magnesium nitrate hexahydrate with cobalt nitrate hexahydrate, nickel nitrate hexahydrate (partly), manganese nitrate tetrahydrate, and iron(III) nitrate nonahydrate and of magnesium chloride hexahydrate with cobalt and nickel chlorides hexahydrates and manganese chloride tetrahydrate, and the of two manganese salts were determined. Those diagrams that showed a simple eutectic were fitted by the Ott equation and where the required BET parameters were available, the magnesium salt rich parts of the liquidus were modeled by means of this method.

The objective of this study was to apply response surface methodology to estimate the emulsifying capacity and stability of mixtures containing isolated and textured soybean proteins combined with pectin and to evaluate if the extrusion process affects these interfacial properties. A simplex-centroid design was applied to the model emulsifying activity index (EAI), average droplet size (D [4,3] ) and creaming inhibition (CI%) of the mixtures. All models were significant and able to explain more than 86% of the variation. The high predictive capacity of the models was also confirmed. The mean values for EAI, D [4,3] and CI% observed in all assays were 0.173 ± 0.015 nm, 19.2 ± 1.0 lm and 53.3 ± 2.6%, respectively. No synergism was observed between the three compounds. This result can be attributed to the low soybean protein solubility at pH 6.2 (<35%). Pectin was the most important variable for improving all responses. The emulsifying capacity of the mixture increased 41% after extrusion. Our results showed that pectin could substitute or improve the emulsifying properties of the soybean proteins and that the extrusion brings additional advantage to interfacial properties of this combination.

This paper provides the results of simulations using an adiabatic capillary tube model which is developed to study the¯ow characteristics in adiabatic capillary tubes used as a refrigerant control device in refrigerating systems. The developed model can be considered as an eective tool of capillary tubes' design and optimization for systems using newer alternative refrigerants. The model is validated by comparing with the experimental data of Li et al. and Mikol for R12 and Melo et al. for R134a. In particular, it has been possible to compare various pairs of refrigerants. It is found that the conventional refrigerants consistently give longer capillary lengths than the alternative refrigerants. For all pairs, the conventional refrigerant consistently give lower pressure drops for both single-phase and two-phase¯ow which resulted in longer tube lengths. In addition, an example of capillary tube selection chart developed from the present numerical simulation is shown. The chart can be practically used to select the capillary tube size from the¯ow rate and ow condition or to determine mass¯ow rate directly from a given capillary tube size and¯ow condition. The results of this study are of technological importance for the ecient design when systems are assigned to utilize various alternative refrigerants.

The chemical composition of silage from Guinea grass, cassava peels, and brewery waste as affected by ensiling duration was assessed through determination of their proximate composition and fiber fractions. Results showed that the ensiling duration had significant (P<0.05) effect on the parameters determined with crude protein (CP) content ranging between 12.02 and 16.12% and neutral detergent fiber (NDF) was between 50.21 and 65.05%. The CP also varied significantly (P<0.05) among the forage-agro by product mixtures of the silage from 7.65 to 15.17% with CP content of 25%GG+75%BW silage being the highest. The forage-agro by product mixtures had varying (P<0.05) influence on the NDF ranging from 47.72% in 75%CAP + 25%BW to 63.85% in 25%GG + 50%CAP + 25%BW silage. The 25%GG + 75%BW silage could be concluded a better feed resource for ruminant animals for its high crude protein content and relatively lower neutral detergent fiber.

The molecular weight distribution has been determined for the galactomannan solubilized from three types of locust bean gum (LBG) flours: single carob seeds, mixtures, and a range of commercial products. To prepare crude endosperm flours from carob seeds with minimal galactomannan degradation, a new extraction and milling method was developed. The method consists of applying a brief thermal shock to the seeds, followed by an extended 3-day swelling period, and manual separation of endosperms; particle size reduction to a flour is accomplished on hydrated endosperms using a centrifugal mill. This method was optimized so that redissolved LBG flours produced solutions with the highest possible viscosity and the least amount of galactomannan degradation as determined by SEC. For the three samples types, the molecular weight distribution, w(M), was found to be unimodal, appearing as a sharply defined main peak (M p E1.1 Â 10 6 g/mol) with a small high molecular weight tail (up to 2.0 Â 10 6 g/mol) and broad low molecular weight tail (down to 0.01 Â 10 6 g/mol); polydispersities (M w /M n ) were estimated to be 1.5-1.8. Variations in M w and [Z] for galactomannans extracted from individual seeds originating from the same carob tree were minimal and nearly indistinguishable from a bulk mixture (6 seeds, M w ¼ 0.96-1.1 Â 10 6 g/mol, [Z] ¼ 14.2-15.1 dl/g). There was a higher variability in these molecular parameters for galactomannans solubilized from commercial LBG flours, which generally exhibited lower M w and [Z], broader distributions, and reduced solubilities (M w ¼ 0.86-1.0 Â 10 6 g/mol, [Z] ¼ 12.4-13.6 dl/g). These side-effects were attributed to damage caused by industrial scale seed processing. The near constancy of M p for the three sample types suggests that the average molecular size of LBG galactomannan varies only slightly due to natural or biological causes. r

Bioassays of Rosmarinus officinalis L. essential oil and blends of its major constituents were conducted using host-specific strains of the two-spotted spider mite, Tetranychus urticae Koch, on bean and tomato plants. Two constituents tested individually against a bean host strain and five constituents tested individually against a tomato host strain accounted for most of the toxicity of the natural oil. Other constituents were relatively inactive when tested individually. Toxicity of blends of selected constituents indicated a synergistic effect among the active and inactive constituents, with the presence of all constituents necessary to equal the toxicity of the natural oil.

Fourier transform Raman spectroscopy and chemometric tools have been used for exploratory analysis of pure corn and cassava starch samples and mixtures of both starches, as well as for the quantification of amylose content in corn and cassava starch samples. The exploratory analysis using principal component analysis shows that two natural groups of similar samples can be obtained, according to the amylose content, and consequently the botanical origins. The Raman band at 480 cm −1 , assigned to the ring vibration of starches, has the major contribution to the separation of the corn and cassava starch samples. This region was used as a marker to identify the presence of starch in different samples, as well as to characterize amylose and amylopectin. Two calibration models were developed based on partial least squares regression involving pure corn and cassava, and a third model with both starch samples was also built; the results were compared with the results of the standard colorimetric method. The samples were separated into two groups of calibration and validation by employing the Kennard-Stone algorithm and the optimum number of latent variables was chosen by the root mean square error of cross-validation obtained from the calibration set by internal validation (leave one out). The performance of each model was evaluated by the root mean square errors of calibration and prediction, and the results obtained indicate that Fourier transform Raman spectroscopy can be used for rapid determination of apparent amylose in starch samples with prediction errors similar to those of the standard method.

This paper presents the performance analysis of an air-to-water vapor compression heat pump system using pure refrigerants and zeotropic refrigerant mixtures. The heat pump system is composed of a compressor, condenser, air cooled evaporator, expansion valve, a receiver tank, a superheater/subcooler, refrigerant mixture unit and some auxiliary and measurement devices. The study focuses on the second law efficiency characteristics of the heat pump system. Comparisons are made between the pure refrigerants and refrigerant mixtures on the basis of the COP and second law efficiency. Also, the effect of the evaporator source inlet temperature on the COP and second law efficiency is presented. It was found that the mixture ratio affects the COP and second law efficiency significantly, and the COP and second law efficiency for the pure refrigerants could be improved by using an appropriate mixture of the refrigerants.

Phenolic compounds exist widely in the influents and effluents of sewage treatment plants (STPs) and most are un-regulated. In this study, a gas chromatography-mass spectrometry (GC-MS) method for the simultaneous analysis of 50 phenolic compounds in wastewater was developed. Deconvolution technology was used to identify contaminants that are covered by co-extracted materials. A mass spectral library containing all 50 silylated phenolic compounds was first established and used for deconvolution. Twelve typical phenolic compounds were selected to optimize the sample preparation procedures. Solid-phase extraction using a C18 cartridge coupled with an HLB cartridge was used for pre-concentration and dichloromethane was used for elution. The solutes were derivatized and analyzed by GC-MS. The blank and matrix spike recoveries ranged from 57.46% to 136.4% and 47.87% to 114.8%, respectively. Method detection limits ranged from 3.64 to 97.64 ng L -1 . The relative standard deviations of all the recovery experiments were lower than 13.6%. The instrument limits of quantification ranged from 0.7 to 87.7 pg. The method has been applied to analyze the influents and effluents of 5 Chinese STPs. Except for regulated phenolic compounds (phenol and 2,4,6-trichlorophenol), three un-regulated phenolic compounds, including 2-chlorophenol, 2,5-dichlorophenol and 2,4-dichloro-3-ethyl-6-nitrophenol were identified in the effluent wastewater. The detected concentrations of un-regulated phenolic compounds could possibly cause environmental effects, indicating that immediate attention is required to prevent complications. identify, quantify, phenolic compounds, deconvolution, wastewater Citation:

Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. The desalination process is suitable for operation at low temperatures and may be driven by waste heat with low exergy. It is demonstrated that the DDD process can yield a fresh water production efficiency of 4.5% with thermal energy consumption of 0.56 kWh per kilogram of fresh water production based on a feed water temperature of only 50°C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day. Downloaded From: http://energyresources.asmedigitalcollection.asme.org/ on 01/17/2015 Terms of Use: http://asme.org/terms 224 Õ Vol. 126, SEPTEMBER 2004 Transactions of the ASME Downloaded From: http://energyresources.asmedigitalcollection.asme.org/ on 01/17/2015 Terms of Use: http://asme.org/terms

Our recently completed wide-ranging correlations for the tbermophysical properties of methane and ethane fluids have enabled us to improve the extended corresponding states calculations for the properties of the binary mixtures. The pure fluid equations are based on the analytic Schmidt-Wagner equation of state and give improved results in the general region of the critical point. We use these pure fluid equations (and a reference fluid for which an equivalent equation is known) to calculate properties and compare with experimental PVT data, isochoric heat capacities, and sound speeds of binary mixtures of methane and ethane. We also examine the properties at the vaporliquid boundary and compare the representation from the classical extended corresponding states calculations with quantities derived from a scaling theory model. The shape of the binary mixture phase boundary is improved with this model, however our new representation of the single phase properties provides only a slight improvement over models based on modified Benedict-Webb-Rubin pure fluid equations of state.

Aloe plants have been widely documented in artists’ treatises dating from the sixteenth to the nineteenth century as a source of colorant to achieve lustrous golden glazes on tin- and silver-foiled objects and warm-toned finishes on musical instruments, such as violins. Aloe extracts contain characteristic anthraquinone and phenolic components which impart a distinctive orange tone and fluorescence to mixtures containing them. Because of the low concentration of colorant in the coatings and its probable degradation by high temperature during manufacture, the identification of aloe in heated oil–resin mixtures represents an analytical challenge. For this reason, the possible presence of aloe in glazes and coatings has been largely overlooked. This paper describes various analytical approaches to the identification of aloe in historic samples, from comparison with results obtained from reference standards and mock-up samples. Complementary analytical techniques including thermally assisted hydrolysis and methylation–gas chromatography–mass spectrometry, high-performance liquid chromatography, laser desorption–mass spectrometry, matrix-assisted laser desorption-ionization-mass spectrometry and surface-enhanced Raman scattering were used. Different chemical markers were identified by the individual methods and the advantages and limitations of each technique for the identification of aloe in oil–resin varnishes are discussed.

In this study, ultrasonic velocity measurements were used to estimate the alcohol type and volume concentration in water–alcohol binary mixtures. Varying mixtures of ethanol in water and methanol in water were prepared and the ultrasonic velocities for each concentration level were measured between 10 and 50 °C. Results of the statistical analyses indicated that ultrasonic velocity measurements can be used to distinguish between ethanol and methanol in a water–alcohol binary mixture and to estimate the alcohol concentration level. The results were validated by testing three commercial liquids with a known ethanol concentrations and one commercial liquid with known methanol concentration.

Natural rubber-polyolefin (70/30) blends have been studied by incorporation of modified rubber and plastic phases with a view to make the heterogeneous phases compatible. The modified rubbers used were epoxidized natural rubber (ENR) and sulfonated ethylene-propylene diene rubber (S-EPDM) a t a level of 20 parts. Other rubbers such as chlorinated polyethylene (CPE) and ethylene propylene dime rubbers (EPDM) were also used at a level of 20 parts in the natural rubber-polyethylene (NR/PE) systems. The plastic phase was chemically modified with maleic anhydride (MA) in presence of benzoyl peroxide (BPO) and used at a concentration of 10% of PE, i.e., PEm. The tensile properties such as the modulus, elongation at break, tensile strength, and hysteresis were studied. NR/ENR/PEm/PE shows the greatest improvement in tensile strength (45% over control NR/PE). NR/S-EPDM/PEm/PE also shows similar improvement, although the hysteresis loss decreases. The change in these properties could be related to the adhesive strength. This was found to be improved by the incorporation of modified rubber and modified plastic phases. The best adhesion values have been obtained with NR/ENR/PEm/PE and NR/S-EPDM/PEm/PE. Thus, a correlation between tensile and adhesive strength was obtained for all the systems. The increase in adhesive strength is due to chemical reactions between the various phases. Probable chemical reactions have been suggested. Morphological observations show that the phases are interpenetrating, and this is consistent with the increased tensile strength. The natural rubber-polypropylene (NR/PP) systems do not offer good strength properties with the modified P P and modified rubbers. The adhesive strength also decreases with the incorporation of the modified system. The hysteresis properties show some improvement.

Study objectives were to formulate a nutritious acceptable snack bar partially replacing oats with micronized flaked lentils (MFL), and to identify the sensory attributes that contribute to consumer acceptability. Six MFL snack bar formulations exhibiting a wide range of flavor and textural characteristics were developed from a mixture designed experiment. These bars and two commercial bars were evaluated by a consumer panel (n = 62) and a descriptive panel (n = 11). The highest mean acceptability values for one commercial sample (6.5) and three MFL bars (6.0) were not significantly different and corresponded to ‘like slightly’ on the 9-point hedonic scale. External preference mapping determined that sweetness, grainy and lentil flavors, hardness, cohesiveness, cohesiveness of mass and moistness had the greatest influence on consumer acceptability. MFL bars contained more dietary fibre, protein and iron in addition to an approximate sevenfold increase in folate over the all oat counterpart.

Lemon juice, vinegar and the mixture of lemon juice and vinegar (1:1) were tested for their effectiveness in reducing the counts of inoculated Salmonella typhimurium (approximately 6 and 3 log cfu/g) on carrots. Treatment of carrot samples with lemon juice vinegar alone for different exposure times (0, 15, 30 and 60 min) caused significant reductions ranging between 0.79 -3.95 and 1.57 -3.58 log cfu/g, respectively, while the number of pathogens was reduced to an undetectable level after 30min treatment by combined used lemon juice vinegar. D

Mixtures of starch, xanthan gum and either polyvinyl alcohol, epichlorohydrin, valeric acid or adipoyl chloride were extruded. Properties of extrudates including apparent viscosity, water solubility, water absorption indices and exrudate expansion were measured for different proportions of xanthan gum, 70% amylose starch (with or without irradiation) and chemical agents. Extrusion with chemical agents and irradiation changed physical properties of both starch and xanthan gum. Expansions of extrudates were higher than that of starch. Viscosity of extrudates increased with xanthan gum concentration. The addition of 1% (w/w) polyvinyl alcohol had the greatest effect of the chemical agents. Irradiation increased the apparent viscosity of starch-xanthan gum mixtures.

The biological activity of lycopene can be enhanced by the presence of these other active antioxidants such as β-carotene, vitamin E, and vitamin C. Since many of these natural antioxidants are consumed together in foods, the potential for synergistic interactions is high in the human diet. The aim of this study was to determine what concentrations and combinations of antioxidants among lycopene, vitamin E, vitamin C, and β-carotene are capable of producing synergistic antioxidant effects, based on tomato-based food products. Solutions of the scavenging capacities of lycopene, vitamin E, vitamin C, and β-carotene, alone and in different combinations were measured using the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Three different levels of each antioxidant were used. A comparison of the scavenging capacity (antioxidant activity) of the combinations of antioxidants to the arithmetic sum of the scavenging capacities of the individual antioxidants was used to calculate the synergistic effects (SEs) between the antioxidants. The results showed that the mixture that had the highest SEs (P<0.01) was the solution combining lycopene (15 μmol/L), vitamin E (5.0 μmol/L), vitamin C (0.16 μmol/L), and β-carotene (10.83 μmol/L). The results suggest that the antioxidant property of this combination was substantially superior to the sum of the individual antioxidant effects, and these interactions can enhance the antioxidant effectiveness of natural antioxidants. The results could guide in the formulation and development of functional food products that have high antioxidant potential.

The main purpose of this work was to develop a mathematical model and computer programs for ejector studies in refrigeration cycles. Version A of the program was written for optimal ejector design while Version B, with more built-in flexibility, was intended for simulation. The study is a one-dimensional analysis of compressible refrigerant flow, based on a forward marching technique of solution for the conservation equations. Refrigerant properties were evaluated using NIST [NIST Standard Reference Database 23, NIST Thermodynamics and Transport Properties of Refrigerants and Refrigerant Mixtures, 1998, REFPROP, Version 6.01] subroutines for equations of state solutions. The approach assesses the flow locally and provides the flexibility of returning upstream for correcting adjustments. Model validation against the R141b data of Huang et al. [Int. J. Refrig. 22 (1999) 354] has shown very good agreement under all conditions. Analysis with refrigerant R142b was performed for typical refrigeration conditions. The entrainment ratio x, the compression ratio P 6 /P 2 and geometric parameters such as diameters and axial dimensions were used to assess performance. Local distributions of pressure, temperature and Mach number were obtained for typical conditions and the mixing chamber was found to greatly impact operation and performance, by controlling the shock wave occurrence and intensity. Crown

¿Cuál es el origen de todas las cosas? A pesar de su gran diversidad, ¿tienen una raíz común? ¿Tuvo el mundo un comienzo? ¿Cómo surgió la vida en la tierra? Tales preguntas, que aún provocan a los científicos, fueron formuladas por vez primera por los primeros pensadores griegos. Anaxágoras responde a ellas poniendo al inicio del tiempo una confusa mezcla de todas las cosas sobre la cual obró un ser llamado Intelecto, quien dio lugar al orden del mundo que hoy contemplamos. Con ello, este autor presocrático comienza a plantear algunas cuestiones filosóficas que perdurarán hasta nuestros días: la constitución de la materia, la naturaleza del conocimiento sensorial e intelectual, la intervención de Dios en el mundo… Este libro pretende analizar cuidadosamente la filosofía de Anaxágoras prestando atención a los dos aspectos principales de su doctrina: la mezcla e Intelecto. Su comprensión de la realidad física como una mezcla tiene consecuencias filosóficas de gran interés y constituye quizá la más sugestiva entre las primeras concepciones de la materia. Por otro lado, Intelecto es, según Anaxágoras, quien provoca la variedad de los seres a través del movimiento. Así, nuestro filósofo distingue del sustrato material la causa de sus cambios, la cual se hallaría, además, dotada de inteligencia. Tales rasgos de la filosofía de Anaxágoras atrajeron la atención de los grandes filósofos clásicos, particularmente de Aristóteles. El segundo gran objetivo de este libro es, pues, recorrer el camino por el cual discurrieron las enseñanzas de Anaxágoras, desde que fueron expuestas por él en Atenas, justo durante el siglo que definió la preponderancia intelectual de dicha polis durante siglos, hasta que llegaron a oídos de Aristóteles, el testigo más determinante para comprender a Anaxágoras.

Dans la Mauritanie contemporaine, la revendication de l'arabe fait figure de principe fondamental de l'entité maure. Pourtant les populations sahariennes du Sahara occidental furent longtemps berbérophones et mirent sans doute plusieurs siècles à changer de « langue maternelle ». C'est d'abord sur cette arabisation dialectale que je m'interroge, en montrant qu'on ne peut pas la couper complètement du mouvement d'islamisation qui l'a précédée et qui semble avoir influé fortement sur l'image que ces populations pouvaient se faire d'elles-mêmes.
Si, à partir du 18ᵉ siècle, l'arabité culturelle de cette région prend des contours plus nets, il faut prêter attention au fait que, derrière l'unité apparente du terme « arabe », se cache une dualité mouvante — ce qu'on appelle la diglossie arabe littéraire/dialecte —, à laquelle correspondent deux formes culturelles distinctes. Je propose ici de caractériser la culture savante des zwâye comme « aurale » (par delà la dichotomie écrit/oral) par opposition à l'oralité de la culture populaire en dialecte, telle qu'elle s'incarne notamment chez les musiciens-chanteurs.
Dans la dernière partie, j'étudie l'évolution récente de la diglossie et les tentatives faites pour échapper aux difficultés posées par cette opposition, qu'elles restent à l'intérieur du domaine arabe ou qu'elles choisissent d'en sortir. Là encore le poids de l'idéologie se fait sentir et les représentations des locuteurs influent sur leurs productions langagières.

An experimental study was carried out on a scraped surface heat exchanger used for freezing of waterethanol mixture and aqueous sucrose solution. The influence of various parameters on heat transfer intensity was established: product type and composition, flow rate, blade rotation speed, distance between blades and wall. During starting (transient period) the solution is first supercooled, then ice crystals appear on the scraped surface (heterogeneous nucleation) and no more supercooling is observed. It seems that, when blades are 3 mm far from the surface, a constant ice layer is formed having this thickness and acting as a thermal resistance. But when the blades rotate at 1 mm from the surface, periodically all the ice layer is removed despite the surface is not really scraped. This could simplify ice generator technology. An internal heat transfer coefficient was defined; it depends mainly on rotation speed. Correlations were proposed for its prediction, which could be applied, at least as a first approach, for the most common freezing applications of scraped surface heat exchanger i.e. ice creams (which are derived from sucrose solutions) and two-phase secondary refrigerants (which are principally ethanol solutions).

This paper compares the normalized difference vegetation index (NDVI) and percent impervious surface as indicators of surface urban heat island effects in Landsat imagery by investigating the relationships between the land surface temperature (LST), percent impervious surface area (%ISA), and the NDVI. Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data were used to estimate the LST from four different seasons for the Twin Cities, Minnesota, metropolitan area. A map of percent impervious surface with a standard error of 7.95% was generated using a normalized spectral mixture analysis of July 2002 Landsat TM imagery. Our analysis indicates there is a strong linear relationship between LST and percent impervious surface for all seasons, whereas the relationship between LST and NDVI is much less strong and varies by season. This result suggests percent impervious surface provides a complementary metric to the traditionally applied NDVI for analyzing LST quantitatively over the seasons for surface urban heat island studies using thermal infrared remote sensing in an urbanized environment.

Horizontal tube a b s t r a c t Heat transfer of ice slurry flow based on ethanol-water mixture in a circular horizontal tube has been experimentally investigated. The secondary fluid was prepared by mixing ethanol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 C). The heat transfer tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 22% depending on test performed. Measured heat transfer coefficients of ice slurry are found to be higher than those for single phase fluid, especially for laminar flow conditions and high ice mass fractions where the heat transfer is increased with a factor 2 in comparison to the single phase flow. In addition, experimentally determined heat transfer coefficients of ice slurry flow were compared to the analytical results, based on the correlation by Sieder and Tate for laminar single phase regime, by Dittus-Boelter for turbulent single phase regime and empirical correlation by Christensen and Kauffeld derived for laminar/turbulent ice slurry flow in circular horizontal tubes. It was found that the classical correlation proposed by Sieder and Tate for laminar forced convection in smooth straight circular ducts cannot be used for heat transfer prediction of ice slurry flow since it strongly underestimates measured values, while, for the turbulent flow regime the simple Dittus-Boelter relation predicts the heat transfer coefficient of ice slurry flow with high accuracy but only up to an ice mass fraction of 10% and Re cf > 2300 regardless of imposed heat flux. For higher ice mass fractions and regardless of the flow regime, the correlation proposed by Christensen and Kauffeld gives good agreement with experimental results.

Fresh cementitious pastes can be viewed as suspensions of particles of many different sizes (from several tens of nm to 100 μm) in a continuous fluid phase. This broad poly-dispersity implies that various interactions such as surface forces (or colloidal interactions), Brownian forces, hydrodynamic forces or various contact forces between particles interplay. Depending on the volume fraction of the particles in the mixture, the use of admixtures or the magnitude of either the applied stress or strain rate, one or several of these interactions dominate. Our objective here is not to quantitatively predict rheology of cement pastes but rather to understand and classify the situations where, depending on composition and processing, one or other of the physical phenomena will control the macroscopic behavior. The result of this analysis is a conceptual diagram of predominant interactions in flowing cementitious suspensions under simple shear, as a function of shear rate and solid fraction.

Blends of LDPE and rice or potato starch were extruded in the presence of varying amounts of water, hot pressed and studied with regard to their mechanical properties and their gas/water permeability and biodegradability before and after storage. The presence of high starch contents ( > 30%, w/w) had an adverse effect on the mechanical properties of LDPE/starch blends. Gas permeability and water vapour transmission rate increased proportionally to the starch content in the blend. Several theoretical and semiempirical calculations for mechanical properties and gas permeability were carried out and possible interpretations were provided for the occasionally observed deviations between the experimental and the theoretical values. The biodegradability rate of the blends was enhanced when the starch content exceeded 10% (w/w). 0

Цветознанието е наука, която изучава свойствата на цветовете и приложението им в различни области на живота. По сложни емоционални състояния предизвикват цветовете в произведенията на изобразителното изкуство. Тяхното въздействие далеч надхвърля границите на непосредствените усещания, асоциира се в трайни и силни чувства. Същият смисъл е вложен и в думите на големия съветски художник Кузма Петров-Водкин: "Има цветове, раздразващи и успокояващи, крещящи, спорещи един с друг и живеещи ласкаво един до друг. В тяхната борба или съгласие се ражда въздействието им върху човека". Йохан Волфганг Гьоте е един от първите изследователи в областта на цветовите възприятия.Той посвещава на това изследване почти две десетилетия и пръв свързва различното въздействие на цветовете с психически процеси.

Background: Naturally occurring antioxidants were used to regulate the skin damage caused by ultraviolet (UV) radiation because several antioxidants have demonstrated that they can inhibit wrinkle formation through prevention of matrix metalloproteinases (MMPs) and/or increase of collagen synthesis.Objective: We examined the effect of oral administration of the antioxidant mixture of vitamin C, vitamin E, pycnogenol, and evening primrose oil on UVB-induced wrinkle formation. In addition, we investigated the possible molecular mechanism of photoprotection against UVB through inhibition of collagen-degrading MMP activity or through enhancement of procollagen synthesis in mouse dorsal skin.Methods: Female SKH-1 hairless mice were orally administrated the antioxidant mixture (test group) or vehicle (control group) for 10 weeks with UVB irradiation three times a week. The intensity of irradiation was gradually increased from 30 to 180 mJ/cm2. Microtopographic and histological assessment of the dorsal skins was carried out at the end of 10 weeks to evaluate wrinkle formation. Western blot analysis and EMSA were also carried out to investigate the changes in the balance of collagen synthesis and collagen degradation.Results: Our antioxidant mixture significantly reduced UVB-induced wrinkle formation, accompanied by significant reduction of epidermal thickness, and UVB-induced hyperplasia, acanthosis, and hyperkeratosis. This antioxidant mixture significantly prevented the UVB-induced expressions of MMPs, mitogen-activated protein (MAP) kinase, and activation of activator protein (AP)-1 transcriptional factor in addition to enhanced type I procollagen and transforming growth factor-β2 (TGF-β2) expression.Conclusion: Oral administration of the antioxidant mixture significantly inhibited wrinkle formation caused by chronic UVB irradiation through significant inhibition of UVB-induced MMP activity accompanied by enhancement of collagen synthesis.

The steady and dynamic shear properties of ketchup-processed cheese (K-PC) mixtures were investigated at different temperatures (10-50°C) and PC concentrations (0-30%). The K-PC mixtures showed a shear-thinning behavior with low magnitudes of yield stress. The consistency coefficient (K) and apparent viscosity (g 50 ) decreased with increase in temperature and concentration. The mixtures followed the Arrhenius temperature relationship, indicating that the magnitudes of activation energies (E a ) were in the range of 8.83-17.16 kJ mol À1 . Storage (G 0 ), loss (G 00 ) and complex (G*) modulus increased with increase in frequency while complex viscosity (g*) decreased. The K-PC mixtures at concentrations of 0-15% exhibited weak gel-like behavior. Increase in the PC concentration resulted in a decrease in G*, G 0 , G 00 and g* up to the 15% of PC concentration, showing a plateau value between 0% and 30% concentrations. Cox-Merz rule was not applicable to K-PC mixtures.

Phenolic compounds exist widely in the influents and effluents of sewage treatment plants (STPs) and most are un-regulated. In this study, a gas chromatography-mass spectrometry (GC-MS) method for the simultaneous analysis of 50 phenolic compounds in wastewater was developed. Deconvolution technology was used to identify contaminants that are covered by co-extracted materials. A mass spectral library containing all 50 silylated phenolic compounds was first established and used for deconvolution. Twelve typical phenolic compounds were selected to optimize the sample preparation procedures. Solid-phase extraction using a C18 cartridge coupled with an HLB cartridge was used for pre-concentration and dichloromethane was used for elution. The solutes were derivatized and analyzed by GC-MS. The blank and matrix spike recoveries ranged from 57.46% to 136.4% and 47.87% to 114.8%, respectively. Method detection limits ranged from 3.64 to 97.64 ng L -1 . The relative standard deviations of all the recovery experiments were lower than 13.6%. The instrument limits of quantification ranged from 0.7 to 87.7 pg. The method has been applied to analyze the influents and effluents of 5 Chinese STPs. Except for regulated phenolic compounds (phenol and 2,4,6-trichlorophenol), three un-regulated phenolic compounds, including 2-chlorophenol, 2,5-dichlorophenol and 2,4-dichloro-3-ethyl-6-nitrophenol were identified in the effluent wastewater. The detected concentrations of un-regulated phenolic compounds could possibly cause environmental effects, indicating that immediate attention is required to prevent complications. identify, quantify, phenolic compounds, deconvolution, wastewater Citation:

Energetic glycidyl azide polymer (GAP) was synthesized from polyepichlorohydrin (PECH) precursor. Thermal decomposition behavior of a mixture of GAP and nitramine oxidizer (4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX)) was investigated by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the decomposition temperature of TEX is unaffected by the presence of GAP in the GAP/TEX mixture. Kinetics of degradation of GAP/TEX mixture was studied by a model-free method and the results were compared with that of the pure components. The study suggested that the decomposition kinetics is controlled by the degradation of GAP during the initial stages of conversion (α > 0.25) whereas the later stages (0.25 ≤ α ≤ 1) are determined by that of TEX. Mechanistic interpretation has been provided to the observed activation energy dependencies by using a combination of optical microscopy (OM) and Fourier transform infrared spectroscopy (FTIR).

The relative performance of various supplementary cementitious materials (SCMs) can be compared with that of portland cement using the practical concept of the efficiency factor (or χ value). This study describes the use of artificial neural networks (ANNs) for the prediction of the efficiency factor of ground-granulated blast-furnace slag (GGBFS) in concrete based on published test results. Feed-forward back-propagation neural networks have been used. The ANN model was established by the incorporation of a large experimental database and by appropriately choosing the architecture and training process. The introduced ANN model provided a more accurate tool to calculate χ and capture the effects of five main parameters: concrete composition (the waterbinder ratio [w/b]; cement dosage; and the GGBFS replacement level); age; and curing temperature, confirming the reported experimental data. This study shows that the use of this model for numerical investigations on the parameters affecting the efficiency of SCMs in concrete is successful. A mathematical model was also developed based on the ANN model's results for predicting the χ value of GGBFS in terms of percentage replacement (from 0 to 80%) and concrete age (from 2 to 90 days), as these are considered the most important factors affecting concrete strength. This evaluation makes it possible to design GGBFS concretes for a desired strength at any given age and replacement level.