melange

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.

White Island volcano comprises three main lava types: (1) silicic andesite, forming Western Cone and a tholoid at Troup Head, (2) dacite forming the Central Cone, and (3) mafic-silicic andesite erupted in March 1977 from the currently active crater. All lavas are calc-alkalic and medium-K orogenic types. The older andesites of Western Cone and Troup Head were probably formed from chemically dissimilar parental magmas by processes of assimilation and fractional crystallisation (AFC). Andesite blocks and bombs ejected during phreatomagmatic activity in March 1977 are geochemically primitive having high Mg-numbers, high Cr and Ni contents, and containing forsteritic olivine. They cannot be derived from magmatic compositions similar to known basaltic lavas of Taupo Volcanic Zone, and it is possible that the blocks are hybrid magmas resulting from mixing of a high-Mg basalt parent and Central Cone dacite. The bombs appear to be fractionated derivatives. Central Cone dacites may also be AFC derivatives of a common parent to the 1977 lavas, in which substantial chemical diffusion has occurred. Their earlier eruption might represent unloading of a zoned magma chamber.

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.

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.

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

Pawpaw [Asimina triloba (L.) Dunal] is a native American fruit tree that has potential as a new fruit crop or for use in landscapes, but little information is available to nurseries on the production of containerized plants. In greenhouse experiments, growth of pawpaw seedlings in Rootrainers was examined in three fertilization regimes, two root-zone temperatures, and four substrates [ProMix, 6 pine bark: 1 sand (v/v), 1 sand: 1 sphagnum peat, and 4 pine bark: 1 sand: 1 sphagnum peat medium]. A similar germination rate of 80% was obtained in all substrates. Weekly fertigation treatments were imposed when seedlings had 2 to 3 leaves, at 0, 50, and 100 mg·L-1 N as Peters 20N-8.6P-16.6K water-soluble fertilizer plus soluble trace elements. After 140 days at the highest fertilizer rate, plant height, leaf number, and dry weight (roots, shoots, and total plant) were greater in ProMix and 1 sand:1 sphagnum peat than in 6 pine bark: 1 sand (v/v) or 4 pine bark: 1 sand: 1 sphagnum peat. Als...

Cereal Chem. 79(2):178-182 Crumb softness and improved shelf life of bread is often achieved by incorporating expensive shortenings in the formulation. We hypothesized that similar results could be achieved by blending bread wheat flour with waxy (low amylose) durum wheat flour. White pan bread was baked from 10, 20, and 30% waxy durum wheat flour composites and evaluated for loaf volume and crumb firmness over a period of 0, 3, and 5 days. The loaf volumes were not affected by the waxy flour blends. However, as staling progressed over 3-5 days, significant firming of crumb was observed in the control sample compared with loaves containing waxy flour. The firmness was inversely proportional to the level of waxy flour used in the blend. A 20% waxy wheat flour blend was optimal in retarding staling while producing bread quality comparable with the control. It was further established that bread made with 20% waxy flour gave lower firmness values after 5 days of storage in comparison to bread made with 3% shortening. These results suggest that 20% waxy wheat flour could substitute for use of shortening to achieve desirable crumb softness and to retard staling upon storage.

... Demir Altıner c , E-mail the corresponding author ,; Sevinç Özkan-Altıner c , E-mail the corresponding author ,; Nilgün Okay d , E ... the Tauride sequences are characterized by carbonate deposition in the Middle Triassic to Late Cretaceous interval, whereas the Sakarya Zone of the ...

CHAPTER 1 INTRODUCTION CHAPTER 2 REVIB\ry OF LITERATURE 2.l LENTILS 2.1.1Production 2.L.2Usage 2.1.3 Demand 2.1.4 Nutrient Content 2.2 LENTIL PROCESSING 2.2.I Micronization 2.2.2Flal<tng 2.3 SIMLF LIFE TESTING 2.4 PRODUCT DEVELOPMENT 2.4.1 New Product Definition 2.4.2 New Product Rationale 2.5 SNACK BAR PRODUCTION 2.5.1Processing 2.5.2Formulation 2.5.3 Ready Made Bars 2.5.4Ideal Charactedstics of Snack Bars 2.6 TI#, PRODUCT DEVELOPMENT PROCES S 2.7 TOOLS FOR PRODUCT DEVELOPMENT 2.7 .I Intemal Preference Mapping 2.7 .2 Extenal Preference Mapping 2.7 .3 Experiment Design for Recipe Formulations CHAPTER 3 MATERIALS AND METHODS 3.1 Materials 3.1.1 Micronized Flaked Lentils 3 .I.2 Ingredients 3. 1.3 Commercial Samples 3.2 Methods 3.2.1, Bar Formulation and Feasibility 53 75 75 15 16 76 78 79 79 9I 9I 93 100 100 100 r04 106 106 106 V1 4.5 .3 Attrlbute Appropriateness 4.5.4 Internal Preference Mapping 4.6 Descriptive Panel 4.6.1 Multivariate Analysis of Variance 4.6.2 Analysis of Variance 4.6.3 Pnncipal Component Analysis 4.6.4 Exïenal Preference Mapping CHAPTER 5 CONCLUSIONS AND LIMITATIONS AND RECOMMENDATIONS 5.1 Conclusions 5.2 Limitations 5.3 Recommendations References Appendices 118 t2r r24 124 r25 134 r4t r52 t52 t54 155 r57 r66

The effect of glycerol on both micellar formation and the structural evolution of the sodium dodecyl sulfate (SDS) aggregates in the context of the action mechanism of the cosolvent has been studied. The critical micelle concentration and the degree of counterion dissociation of the surfactant over a temperature range from 208 8 8 8 8C to 408 8 8 8 8C were obtained by the conductance method. The thermodynamic parameters of micellization were estimated by using the equilibrium model of micelle formation. The analysis of these parameters indicated that the lower aggregation of the surfactant is mainly due to a minor cohesive energy of the mixed solvent system in relation to the pure water. The effect of glycerol on the mean aggregation number of the micelles of SDS was analyzed by the static quenching method. It was found that the aggregation number decreased with the glycerol content. This reduction in the micellar size seems to be controlled by an increase in the surface area per headgroup, which was ascribed to a participation of glycerol in the micellar solvation layer. Studies on the micropolarity of the aggregates, as sensed by the probe pyrene, indicated that this microenvironmental parameter is almost unaffected by the presence of glycerol in the mixture. However, an increase in the micellar microviscosity at the surface region was observed from the photophysical behavior of two different probes, rhodamine B and auramine O. These results suggest a certain interaction of the cosolvent in the micellar solvation of SDS micelles.

The percentage of mixtures as compared to single plants in plant use reports varied between 32 and 41%, depending on the geographic location (NYC or DR) and participant status (lay person or specialist). Respiratory conditions, reproductive health and genitourinary conditions ...

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.

True-boiling-point distillation is an efficient batch distillation being one of the most commonly applied techniques to study the polydispersity of complex hydrocarbon mixtures. True-boiling-point curves are obtained by plotting the temperature at the top of the column versus the fraction of mass distilled. The name expresses the assumption that the complex mixture is separated into its components according to their boiling points. However, in the case of azeotropy (e.g. between aliphatics and aromatics) this assumption is not correct. Therefore, based on continuous thermodynamics, a method is developed for describing quantitatively the azeotropic effect. The method presumes distillation of pure compounds or of azeotropic mixtures (if the efficiency of the column is sufficiently large). It is demonstrated for mixtures consisting of a petroleum fraction (low in aromatics) and of alcohols.

It is well known that the presence of non-condensable gases inside a compression vapour refrigerating circuit introduces an additional thermal resistance at the condenser, which can significantly decrease the energy efficiency of the system. However, this problem so far has been investigated mainly for shell and tube condensers of large capacity and limited information is available on small systems, as is the case for household appliances where the internal volumes are extremely reduced and therefore a very small amount of non-condensable gas has large effect. Moreover, non-condensable gas behaves differently when condensation takes place outside tubes (shell and tube condensers) or inside tubes (condensers of small appliances); in the first case all heat transfer area is wrapped by a gas layer, whereas in the second case non-condensable gas is collected at the end of the tube. The effect of non-condensable gas in this work is experimentally investigated by injecting controlled amounts of air into a refrigerating circuit and by recording the thermal and electric variables during different modes of operation (steady state and cyclic running). The tested refrigerating circuits are part of two appliances on the market, a household refrigerator and a vertical freezer. The presence of non-condensable gas was found to spoil energy efficiency, since it brings about an increase in condensing pressure and a concomitant decrease in evaporating temperature, although larger liquid subcooling partially compensates for the first negative effects: the reason for this behaviour is the clogging action of bubbles of gaseous mixture (air and refrigerant vapour) that enter the capillary tube.

Obtaining rapid mixing in microfluidic systems is a problem that must continue to be addressed if microelectromechanical systems are to attain their full potential in commercial markets. We present the paradigm of “designing for chaos” as a general framework for enhancing mixing in microfluidic applications. Designing for chaos is based on a fundamental understanding of the kinematics underlying the mixing process, freeing the MEMS researcher to work with design guidelines instead of empirically determined ...

This work reports on a study of the uptake of cadmium and zinc, both singly and in combination (in equimolar concentrations), by the yeast Saccharomyces cerevisiae. It is shown that in all cases, an instantaneous surface adsorption occurred, followed by a slower uptake process. In the dual metal ion system, the presence of the coion did not appreciably affect the instantaneous uptake of the other metal, suggesting that the two metal ions may be bound to different sites on the cell. The longterm uptake was however metal-dependent; inhibition in the uptake of zinc by cadmium was observed, but zinc had no effect on the long-term uptake of cadmium. Noninteraction and antagonism were demonstrated in the uptake of cadmium and zinc respectively by Saccharomyces cerevisiae. Treatment of the yeast cells with heat, acid, alkali or formaldehyde was found to enhance the instantaneous specific uptake. Formaldehyde-treated cells consistently showed significantly greater uptake than non-treated cells.

The potential of NMR spectroscopy and multivariate analysis methods to detect the adulteration of orange juice with pulp wash is demonstrated. Principal component analysis has been applied to 1 H NMR spectra of >300 orange and pulp wash juices, and stepwise linear discriminant analysis was used to classify the samples. A model with six principal components gave a high success rate of classification (94%) for both training and validation sets. An important principal component loading showed that dimethylproline played a key role in the discrimination between the two types of juice, with higher levels in pulp wash. Dimethylproline was not previously known as a marker compound for orange juice adulteration. An ANOVA test revealed at least 21 other NMR signals that differed significantly between the authentic and pulp wash groups. The compounds they represent could be seen as potential marker compounds in addition to dimethylproline. This makes NMR with chemometrics an attractive screening tool with advantages in terms of rapidity, simplicity, and diversity of information provided.

Background: Cancer-related cachexia is caused by a diverse combination of accelerated protein breakdown and slowed protein synthesis. The hypothesis proposed in this study is that supplementation of specific nutrients known to positively support protein synthesis and reduce protein breakdown will reverse the cachexia process in advanced cancer patients. Methods: Patients with solid tumors who had demonstrated a weight loss of at least 5% were considered for the study. Patients were randomly assigned in a double-blind fashion to either an isonitrogenous control mixture of nonessential amino acids or an experimental treatment containing ␤-hydroxy-␤-methylbutyrate (3 g/d), L-arginine (14 g/d), and L-glutamine (14 g/d [HMB/Arg/Gln]). The primary outcomes measured were the change in body mass and fat-free mass (FFM), which were assessed at 0, 4, 8, 12, 16, 20, and 24 weeks. Results: Thirty-two patients (14 control, 18 HMB/Arg/Gln) were evaluated at the 4-week visit. The patients supplemented with HMB/ Arg/Gln gained 0.95 Ϯ 0.66 kg of body mass in 4 weeks, whereas control subjects lost 0.26 Ϯ 0.78 kg during the same time period. This gain was the result of a significant increase in FFM in the HMB/Arg/Gln-supplemented group (1.12 Ϯ 0.68 kg), whereas the subjects supplemented with the control lost 1.34 Ϯ 0.78 kg of FFM (P ϭ 0.02). The response to 24-weeks of supplementation was evaluated by an intent-to-treat statistical analysis. The effect of HMB/Arg/Gln on FFM increase was maintained over the 24 weeks (1.60 Ϯ 0.98 kg; quadratic contrast over time, P Ͻ0.05). There was no negative effect of treatment on the incidence of adverse effects or quality of life measures. Conclusions: The mixture of HMB/Arg/Gln was effective in increasing FFM of advanced (stage IV) cancer. The exact reasons for this improvement will require further investigation, but could be attributed to the observed effects of HMB on slowing rates of protein breakdown, with improvements in protein synthesis observed with arginine and glutamine.

... Abstract. The Sanchez–Lacombe equation of state is known to describe the thermodynamic properties of molecular fluids of arbitrary size, especially polymer–solvent phase behavior. However, it is rarely used for modeling solid–supercritical fluid equilibria. ...

The results of five different commercial single-ply roof-covering products for low-slope roofs, i.e. atactic polypropylene (APP)-modified bitumen, styrene-butadiene-styrene copolymer (SBS)-modified bitumen, ethylene-copolymerized bitumen (ECB), plasticized PVC and ethylene-propylene-diene-methylene (EPD M)-rubber, studied by dynamic mechanical thermal analysis are summarized in this paper. Two samples of each product were tested, one which had only been conditioned at 20 °C, 50% relative humidity, and another which had been immersed in distilled water at 50 °C for 4000 h. The difference in the dynamic properties at the glass transition region of the two samples is discussed. The influence of water immersion on material properties such as Tg and To,set was observed for the products of APP-modified bitumen, SBS-modified bitumen and plasticized PVC. The changes in these material properties may have significance for the durability of the products. Dynamic mechanical thermal analysis can be a useful tool for characterizing products used for single-ply roof coverings of low-slope roofs. It may be useful in understanding how different types of products behave in application with different types of dynamic stresses.

A layered-aquifer model of groundwater occurrence in an atoll island was tested with a solute-transport numerical model. The computer model used, SUTRA, incorporates density-dependent flow. This can be significant in freshwater-saltwater interactions associated with the freshwater lens of an atoll island. Boundary conditions for the model included ocean and lagoon tidal variations. The model was calibrated to field data from Enjebi Island, Enewetak Atoll, and tested for sensitivity to a variety of parameters. This resulted in a hydraulic conductivity of 10today-1 for the surflcia] aquifer and 1000today-1 for the deeper aquifer; this combination of values gave an excellent reproduction of the tidal response data from test wells. The average salinity distribution was closely reproduced using a dispersivity of 0.02m. The computer simulation quantitatively supports the layered-aquifer model, including under conditions of density-dependent flow, and shows that tidal variations are the predominant driving force for flow beneath the island. The oscillating, vertical flow produced by the tidal variations creates an extensive mixing zone of brackish water. The layered-aquifer model with tidally driven flow is a significant improvement over the Ghyben-Herzberg-Dupuit model as it is conventionally applied to groundwater studies for many Pacific reef islands. NOTATION

This paper describes an analysis on the performances of a cascade refrigeration cycle operated with blends of carbon dioxide (CO 2 , or R744) and hydrofluorocarbons (HFC) as the low-temperature working fluid. The aim of this work was to study the possibility of using carbon dioxide mixtures in those applications where temperatures below CO 2 triple point (216.58 K) are needed. The analysis was carried out by developing a software based on the Carnahan-Starling-De Santis (CSD) equation of state (EoS) using binary interaction parameters derived from our experimental data. The properties of the investigated blends (R744/R125, R744/R41, R744/R32, R744/R23) were used to simulate the behavior of a cascade cycle using ammonia (R717) as the high-temperature-circuit working fluid and operating at evaporating temperatures down to K70 8C. The use of a suctionliquid heat exchanger on the low-temperature side of the circuit was also investigated. Results show that the R744 blends are an attractive option for the low-temperature circuit of cascade systems operating at temperatures approaching 200 K.

Blends of poly(p-phenylene vinylene) (PPV), with other polymers were made by film-casting from an aqueous mixture of the water-soluble sulfonium salt precursor to PPV and the second polymer. The rates of chemical doping, using AsF,, and of eledrochemical doping, using perchlorate counter ion, of the PPV component are strongly influenced by the nature of the added macromolecule. In all cases studied the blends appear to be phase separated under all conditions. The most versatile blend was with poly(ethy1ene oxide) (PEO), which could be heated to 225°C without degradation and which yielded the highest electrical conductivity when doped. The utility of blends was demonstrated using freestanding PPV/PEO blend samples as rechargeable battery electrodes.

Graft copolymers of cellulose acetate (CA, d.s.: 2.45) with styrene maleic anhydride random copolymers (SMAs) were synthesized by reacting the hydroxyls on CA backbone with the anhydride on SMA. The formation of graft copolymers leads to compatibilized blends with microscopic phase domains under appropriate conditions. The grafting reaction was studied in detail. The uniform dispersion of SMA in the CA matrix brings new properties to the grafting reaction products. Tests from acetone-cast films showed improved dimensional stability in comparison to cellulose acetate; i.e., in the presence of 50% SMA in the formulation, there is more than 50% reduction on the dimensional change as compared to CA. The dimensional stability of the grafting products is better or comparable to cellulose triacetate. There are, for the alloys, reduced moisture adsorption, improved tensile strength, tensile modulus, reduced elongation, as compared to cellulose acetate. 0 1994 John Wiley & Sons, Inc.

Fourier transform infrared spectrometry (FTIR) and mass spectrometry (MS) have been combined with gas chromatography (CC) for the identification of eluted components in a complex mkcture. The combined technique, GC-FTIR-MS, provides simultaneous GC-FTIR and GC-MS data from a single injection.

In this paper, we report on a new method for computing stability limits (i.e., spinodal curves) and critical points in mixtures containing polydisperse polymers. At points on the spinodal curve, the determinant of a matrix is zero. When the model is an equation of state in temperature, volume and the mole numbers of C components, the matrix is of dimension C by C. Polymer characterization may entail use of very many pseudo-components, thereby complicating evaluation of the necessary determinant. The new analysis in this paper shows that the same result can be obtained by zeroing a determinant with only two dimensions required for a polymer of a given type, regardless of the number of pseudo-components used to characterize the polymer. The analysis does not rely on algebraic operations seeking closed-form evaluation of the determinant. It applies to mixtures with any number of non-polymer species and with more than one type of polymer; features not possible with earlier methods. Critical points are on the stability limit and satisfy a second condition. In this paper, the second criticality criterion is evaluated through an easily obtained third-order numerical derivative of the Helmholtz free energy.

Understanding Archean crustal and mantle evolution hinges upon identification and characterization of oceanic lithosphere. We have discovered and reported a complete, albeit dismembered and metamorphosed Archean ophiolite sequence in the North China Craton. Banded iron formation structurally overlies several tens of meters of variably deformed pillow lavas and mafic flows. These are in structural contact with a 2 km thick mixed gabbro and sheeted dike complex with gabbro screens, exposed discontinuously along strike for more than 20 km. The dikes consist of metamorphosed diabase, basalt, hb-cpx-gabbro, and pyroxenite. Many have chilled margins developed on their NE sides, indicating one-way chilling. The dike/gabbro complex is underlain by several kilometers of mixed isotropic and foliated gabbro, which develop compositional layering approximately 2 km below the sheeted dikes, and then over several hundred meters merge into strongly compositionally layered gabbro and olivine-gabbro. The layered gabbro becomes mixed with layered pyroxenite/gabbro marking a transition zone into cumulate ultramafic rocks including serpentinized dunite, pyroxenite and wehrlite, and finally into strongly deformed and serpentinized olivine and orthopyroxene-bearing ultramafic rocks interpreted as depleted mantle harzburgite tectonites. A U/Pb zircon age of 2.505 Ga from gabbro of the Dongwanzi ophiolite makes it the world's oldest recognized, laterally-extensive complete ophiolite sequence. Characteristics of this remarkable ophiolite may provide the best constraints yet on the nature of the Archean oceanic crust and mantle, and offer insights to the style of Archean plate tectonics and global heat loss mechanisms. The Dongwanzi ophiolite is one of the largest well-preserved greenstone belts in the Central Orogenic belt that divides the North China craton into eastern and western blocks. More than 1000 other fragments of gabbro, pillow lava, sheeted dikes, harzburgite, and podiform-chromite bearing dunite occur as tectonic blocks (tens to hundreds of meters long) in a biotite-gneiss and BIF matrix, intruded by tonalite and granodiorite, in the Zunhua structural belt. Blocks in this metamorphosed Archean ophiolitic mélange preserve deeper levels of oceanic mantle than the Dongwanzi ophiolite. The ophiolite-related

The ability of the lignin-degrading microorganism Phanerochaete chrysosporium to attack polyethylene and polypropylene was investigated using a series of polymer blends containing 10, 20 and 30% lignin obtained from the waste product of pulp and paper industry. In the cultivation medium, lignin peroxidase and Mn(II)peroxidase activities were detected. Degradation was veri®ed by quantitative u.v. spectrophotometric analysis of the cultivation medium and by liberation of CO 2 from the blends. Measurement of the tensile strength after 30-days cultivation showed that the mechanical properties of the polymer blends were decreased during the biodegradation process. The isolation of oligomer fractions by tetrahydrofuran (THF) extraction of biodegraded polymers and their characterization by gel permeation chromatography (GPC), u.v. and Fourier transmission infrared (FTIR) spectroscopy indicates that biotransformation of the lignin component during the cultivation process initiates partial biodegradation of the synthetic polymer matrix.

Monomer liquid crystals (MLCs), polymer liquid crystals (PLCs) and heterogeneous composites are compared. PLCs are classified into categories in function of their molecular structure. Molecular composites (MC) are characterized. Phase diagrams are analysed, and new ways of presenting information on coexisting phases including glassy ones are proposed. Rheoiogy and methods of processing of PLCs and MCs are outlined. Characterization of PLCs including their dielectric behaviour is discussed. Blending of PLCs and properties of the blends of MCs are related to present as well as potential applications of liquid-crystalline and rigid rod materials.

Nd isotopic compositions and 147Sm/144Nd ratios were measured in fifty-eight South African shales and greywackes with depositional ages ranging from 0.2 to 3.3 b.y. Elements such as the rare earths, which are poorly soluble in water and not fractionated during exogeneous processes, preserve the signature of the original crustal source. The 147Sm/144Nd ratios appear to be approximately constant throughout the time interval sampled. We calculated Nd model ages of crustal differentiation. Knowing that the shales represent a true blend of different continental areas we consider these model ages representative of the mean ages of their primitive continental sources. Then, using the inverse technique developed by All6gre and Rousseau in 1984, we computed a growth curve for the continental crust in South Africa. Two periods of important crustal genesis (Archaean and around 1.5 b.y.) can be compared with the observed geology and with other continental crust growth curves obtained in previous studies in southern Africa and in Australia. The observation of large variations in the MgO content and Ni, Cr, U and Th concentrations between Archaean South African shales and post-Archaean samples compared to the constancy of the 147Sm/144Nd ratios leads us to propose that the Archaean crust was composed of both granite (70.5%) and a mafic component (29.5%) which could have been komatiite. The small dispersion of 147Sm/144Nd ratios suggests that erosion and sedimentation processes yielded homogeneous Archaean shales. The present-day continental crust is much more heterogeneous, because it has undergone several episodes of recycling. Thus recent shales are characterized by more variable 147Sm/l'*4Nd ratios.

ABSTRACT This paper describes the complex arrangement of faults and dismembered ophiolites defined by geological mapping or interpreted from Landsat MSS imagery in the Mozambique Orogenic belt of southern Ethiopia. These rocks display the deep-rooted structures of collision zones. Metamorphic grade reached the amphibolite or locally the granulite facies; retrogression to greenschist facies occurs. In the description of the ophiolites, the problem of the location, orientation, and possible linkage of these masses is discussed; low- to high-angle fault (or shear-zone) orientations are presented. The faults were developed largely in a ductile regime and produced a wide range of mylonitic textures. The tectonic history started with a collision (Sabachian events &amp;gt; 826 Ma) followed by strike-slip faulting of basement rocks (a second orogeny &amp;lt;620,&amp;gt;530 Ma). These later events are expressed as: (i) early shears (Baragoian event, 620 Ma); (ii) late shears (Barsaloian event, 570 Ma) which trend north to northwest and have generally straight trends. The early and late shears formed upright folds, open and tight, respectively; (iii) in the southern region, northwest-trending reactivated shears produced gentle refolding and small-scale thrusting (Loldaikan-Kipsingian events 530 Ma). North- and northwest-trending shear zones (&amp;lt;620, &amp;gt; 530 Ma) are interpreted to be the reactivated surface expression of lateral and frontal ramps formed during the collision (&amp;gt; 826 Ma) between the Mozambique Orogenic belt/Arabian-Nubian shield and the old African continent.

This study compared the effect of two functional fermented milks with simple and complex probiotic mixtures on the microbiota and some immune system functions of healthy adults and children. The complex yogurt, containing Lactobacillus casei and other strains of lactobacilli and bifidobacteria, and the simple yogurt, containing only L. casei, were administered daily to healthy volunteers (41 adults and 36 children) for a period of 4 weeks. Microbiological and molecular analyses of faecal samples indicated that the complex product induced a larger increase in the lactic acid bacteria number, compared with the simple product, without significant alterations of the autochthonous species composition. Of the probiotic strains, L. casei showed the best survival rate in faeces. The influences of both products on the immune system were similar, with increase of NK activity and proliferative response to Candida albicans in adults and secretory-IgA in children saliva, indicating that immunomodulating properties were probably supported by common traits in the two products.

The suspended sediment of the Fly River is mostly fine silt with a mean particle size of 8 /olm; the clay fraction makes up less than 20% of the suspended sediment by volume. On reaching brackish water in the estuary, the sediment flocculates. The floes are small (typical mean size of 30 /olm) and are a mixture of fine silt and clay particles, with silt particles dominating. Because of the dominance of silt particles incorporated in the floes, the floes are structurally weak and are destroyed by tidal turbulence at spring tides. The clay particles are selectively trapped in the turbidity maximum zone of the estuary.

The extended corresponding states (ECS) model of Huber et al. (Huber, M.L., Friend, D.G., Ely, J.F. Prediction of the thermal conductivity of refrigerants and refrigerant mixtures. Fluid Phase Equilibria 1992;80:249–61) for calculating the thermal conductivity of a pure fluid or fluid mixture is modified by the introduction of a thermal conductivity shape factor which is determined from experimental data. An

Four species of microalgae (Chaetoceros muelleri, Tetraselmis suecica, Tahitian Isochrysis sp. (T-iso) and Dunaliella tertiolecta) with distinctly dierent fatty acid pro®les were grown in continuous culture and fed to prawn larvae (Penaeus japonicus, P. semisulcatus and P. monodon) as monospeci®c diets. The best two diets (C. muelleri and T. suecica) were also fed as a mixed diet. Experiments were run until the larvae fed the control diet of C. muelleri metamorphosed to Mysis 1. The survival and development (i.e. performance) of the larvae were aected by algal diet, and the diets were ranked in the order of decreasing nutritional value: C. muelleri ³ T. suecica > T-iso > D. tertiolecta. Larvae fed a mixed diet of C. muelleri and T. suecica (2:3 by dry weight) performed as well or better than those fed C. muelleri, and the performance of both these groups of larvae was better than those fed T. suecica. The lipid and carbohydrate compositions of the algae had little or no eect on the lipid and carbohydrate compositions of the larvae or their performance. However, the larvae that performed best (i.e. those fed C. muelleri) had signi®cantly more lipid and carbohydrate than those that performed worst (i.e. those fed D. tertiolecta). Larvae fed C. muelleri or the mixed-algae diet had higher proportions of the essential fatty acids eicosapentaenoic acid [EPA, 20:5(n-3)] and arachidonic acid [ARA, 20:4(n-6)] than the larvae fed on other diets. Furthermore, the larvae fed T. suecica, which showed intermediate performance between larvae fed C. muelleri and T-iso or D. tertiolecta, also had higher proportions of EPA and ARA. Both C. muelleri and T. suecica contained EPA and ARA, but T-iso and D. tertiolecta did not, except for trace amounts of EPA in T-iso. The fatty acid ARA appears to be much more important in the diet of larval prawns than has so far been considered. The level of the essential fatty acid docosahexaenoic acid [DHA, 22:6(n-3)] in the algal diet and the larvae was not related to the performance of the larvae; only C. muelleri and T-iso contained DHA. However, the nauplii contained large proportions of DHA, suggesting that these were sucient to meet the larval requirements for DHA during their development to Mysis 1. Mixed-algae diets could improve the performance of larvae by providing a more comprehensive range of fatty acids.

Six mass spectrometers based on different mass analyzer technologies, such as time-of-flight (TOF), hybrid quadrupole-TOF (Q-TOF), orbitrap, Fourier transform ion cyclotron resonance (FT-ICR), and triple quadrupole (QqQ), installed at independent laboratories have been tested during a single day of work for the analysis of small molecules in negative electrospray ionization (ESI) mode. The uncertainty in the mass measurements obtained from each mass spectrometer has been determined by taking the precision and accuracy of replicate measurements into account. The present study is focused on calibration processes (before, after, and during the mass measurement), the resolving power of the mass spectrometers, and the data processing for obtaining elemental formulae. The mass range between m/z 100 and 600 has been evaluated with a mix of four standards. This mass range includes small molecules usually detected in food and environmental samples. Negative ESI has been tested as there is almost no data on accurate mass (AM) measurements in this mode. Moreover, it has been used because it is the ESI mode for analysis of many compounds, such as pharmaceutical, herbicides, and fluorinated compounds. Natural organic matter has been used to demonstrate the significance of ultrahigh-resolution in complex mixtures. Sub-millidalton accuracy and precision have been obtained with Q-TOF, FT-ICR, and orbitrap achieving equivalent results. Poorer accuracy and precision have been obtained with the QqQ used: 11 mDa root-mean-square error and 6-11 mDa standard deviation. Some advice and requirements for daily AM routine analysis are also discussed here.

Investigations were carried out in order to solidify in cement a low-level radioactive waste of complex chemistry obtained by mixing two process streams, a slurry produced by ultra-filtration and an evaporator concentrate with a salinity of 600 gxL − 1. Direct cementation with Portland cement (OPC) was not possible due to a very long setting time of cement resulting from borates and phosphates contained in the waste. According to a classical approach, this difficulty could be solved by pre-treating the waste to reduce adverse cement-waste interactions. A two-stage process was defined, including precipitation of phosphates and sulfates at 60°C by adding calcium and barium hydroxide to the waste stream, and encapsulation with a blend of OPC and calcium aluminate cement (CAC) to convert borates into calcium quadriboroaluminate. The material obtained with a 30% waste loading complied with specifications. However, the pre-treatment step made the process complex and costly. A new alternative was then developed: the direct encapsulation of the waste with a blend of OPC and calcium sulfoaluminate cement (CSĀ) at room temperature. Setting inhibition was suppressed, which probably resulted from the fact that, when hydrating, CSĀ cement formed significant amounts of ettringite and calcium monosulfoaluminate hydrate which incorporated borates into their structure. As a consequence, the waste loading could be increased to 56% while keeping acceptable properties at the laboratory scale.

This study aims to investigate the behaviour of Malaysian sub-bituminous coal (Mukah Balingian), oil palm biomass (empty fruit bunches (EFB), kernel shell (PKS) and mesocarp fibre (PMF)) and their respective blends during pyrolysis using thermogravimetric analysis (TGA). The coal/palm biomass blends were prepared at six different weight ratios and experiments were carried out under dynamic conditions using nitrogen as inert gas at various heating rates to ramp the temperature from 25°C to 900°C. The derivative thermogravimetric (DTG) results show that thermal decomposition of EFB, PMF and PKS exhibit one, two and three distinct evolution profiles, respectively. Apparently, the thermal profiles of the coal/oil palm biomass blends appear to correlate with the percentage of biomass added in the blends, thus, suggesting lack of interaction between the coal and palm biomass. First-order reaction model were used to determine the kinetics parameters for the pyrolysis of coal, palm biomass and their respective blends.

A naturally occurring Cameroonian smectite clay has been grafted with trimethylpropylammonium groups and the resulting organoclay deposited as thin film onto a glassy carbon electrode (GCE) surface. It was then exploited as a suitable matrix for the accumulation and the electrochemical detection of ascorbic acid (AA) and uric acid (UA). Cyclic voltammetry revealed an increase in oxidation peak responses along with a negative shift of the corresponding anodic peak potential for both AA and UA species when using the organoclay coated GCE in comparison with the bare electrode. The electroanalytical response was improved by coating the electrode surface with a first layer of sublimed ferrocene (FC s), and then overcoating with the organoclay film to avoid the mediator leaching. The resulting bilayer film exhibited good characteristics such as extended linear range and high sensitivities for AA and UA, in cyclic voltammetry and amperometry. Interestingly, the redox mediator FC s was likely to lower overpotentials for AA oxidation (but not for UA), making possible the selective detection of these species in a mixture. The developed method could be used for the determination of AA in a pharmaceutical preparation and for UA in urine.

Two ionic liquids (ILs), namely (S,S)-1-butyl-3-(2′-hydroxy-cyclohexyl)-3H-imidazol-1-ium tetrafluoroborate and (S,S)-1-butyl-3-(2′-acetyl-cyclohexyl)-3H-imidazol-1-ium tetrafluoroborate have been employed as stationary phases in capillary gas chromatography. These new phases exhibit a column efficiency of 1,600 and 2,100 plates m −1 for IL 1 and IL 2, respectively, a wide operating temperature range and good thermal stability (bleeding temperature of 250°C for IL 1 and 160°C for IL 2). Inverse gas chromatography (GC) analyses were used to study the solvation properties of these ILs through a linear solvation energy model. The application of these ILs as new GC stationary phases was studied. These stationary phases exhibited unique selectivity for many organic substances, such as alkanes, ketones, esters, and aromatic compounds. The efficient separation of several mixtures containing compounds of different polarities and the good separation of fatty acid methyl esters (FAMEs) and cis/trans isomers indicate that these ILs may be applicable as a new type of GC stationary phases.

Stretching of material elements in time-periodic cavity flows is investigated numerically. The spatial structure of the stretching field is determined not only by nonchaotic islands and by unstable manifolds of hyperbolic periodic points, but also by singularities of the flow field at the cavity corners. For the short time scales interesting to most mixing applications, regions of very high stretching (good local mixing) are determined by unstable manifolds that pass close to the corners of the cavity. Low stretching (poor local mixing) regions are usually found both inside and near islands. In some cases, however, the unstable manifolds wrap themselves around the islands, preventing the formation of segregated low stretching subregions within the chaotic region.