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Mixed System (mixed + system)
Selected AbstractsRHEOLOGICAL, TEXTURAL AND MICROSTRUCTURE ANALYSIS OF THE HIGH-METHOXY PECTIN/GELATIN MIXED SYSTEMSJOURNAL OF TEXTURE STUDIES, Issue 5 2007H. LIU ABSTRACT The aim of this research was to evaluate the interaction between high-methoxy pectin and gelatin in solution and mixed gel utilizing rheological, texture profile and microstructure analysis. The results showed that the phase separation and association might both exist depending on the ratio of pectin to gelatin in the mixed system. After the pectin addition to the mixed system, the gelation properties of gelatin were improved at suitable conditions. The structure development rate, gel hardness and gel brittleness of the pectin/gelatin mixed system were positively affected by the addition of pectin and from there to expand the application of the mixed system in food industry. PRACTICAL APPLICATIONS Structure-forming polysaccharides and protein provide desired functional properties to a wide range of foods such as gel confectionery products, milk products and fat replacers. As an academic paper, this article provided the information that high-methoxy (HM) pectin could prove the gelation properties of gelatin to corporate audiences. We could find that the ratio of HM pectin to gelatin, and the concentration of these two polymers, dictate the texture properties of the mixed system. The pectin addition to the gelatin system affected the structure development rate, which might save time when the products are processed in practice. The melting temperature was increased with the pectin addition to the gelatin system, which is favorable if it is to be kept under higher temperature. [source] Simulation of an integrated PCM,wallboard systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2003J.-S. Kim Abstract Heat transfer barriers and other practical difficulties do currently hamper the development and application of (phase change materials) PCM,wallboard systems. In this study thermal performance of randomly mixed PCM and laminated PCM,wallboard systems have been numerically evaluated and results compared. The laminated system displayed up to 50% increment in heat flux enhancement and about 18% increase in heat transfer rates. Consequently, the laminated PCM,wallboard system has greater potential for heating and cooling application in buildings than the randomly mixed system. Experimental validation and investigation into manufacturing techniques are however needed to establish the commercial viability. Copyright © 2002 John Wiley & Sons, Ltd. [source] Separation and recovery of cellulose and lignin using ionic liquids: a process for recovery from paper-based wasteJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2009Huma Lateef Abstract BACKGROUND: The production of paper makes use of cellulose and lignin as a raw material, and almost all cellulose and lignin production comes from raw wood materials, contributing to deforestation and resulting in potential environmental harm. It is therefore beneficial to develop technologies for cellulose and lignin recovery for re-use and sustainability of resources. RESULTS: Three imidazolium based ionic liquids (ILs), 1-(2-cyanoethyl)-3-methylimidazolium bromide (cyanoMIMBr), 1-propyl-3-methylimidazolium bromide (propylMIMBr) and 1-butyl-3-methylimidazolium chloride (butylMIMCl), were synthesised by microwave technology and fully characterised by mass spectrometry, thermogravimetric differential scanning calorimetry, thin layer chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopies. Cellulose and lignin were soluble in all three ILs with solubility being greatest in cyanoMIMBr. Regeneration of cellulose and lignin was achieved from saturated solutions of cellulose in IL and lignin in IL for all three ILs. The ILs propylMIMBr and butylMIMBr have been used for the first time in the separation and recovery of cellulose and lignin and regeneration of the IL from a mixture of cellulose and lignin in IL. FTIR analysis confirms successful recovery. CONCLUSIONS: This work demonstrates the ability of ILs to separate and recover cellulose and lignin from a mixed system. Copyright © 2009 Society of Chemical Industry [source] Phase Behavior of a Meat-Starch Extrudate Illustrated on a State DiagramJOURNAL OF FOOD SCIENCE, Issue 8 2002C.I. Moraru ABSTRACT: The phase behavior of a meat-starch extruded system was illustrated on a state diagram. A mixture of meat and potato granules (1.48:1) was extruded with a twin-screw extruder. The extrudates were equilibrated at relative humidities between 0 to 88% and their glass transitions were determined. Starch and proteins were phase separated at macromolecular level and retained their own phase transitions. The state diagram of the system showed that proteins dictated the texture of the mixed system, with starch contributing to the high value of the mechanical properties. Water had a plasticizing effect on both biopolymers. At room temperature, the extrudates with aw < 0.32 were glassy, while those with aw > 0.57 were rubbery. [source] MIDDLE MIOCENE DASHAVA FORMATION SANDSTONES, CARPATHIAN FOREDEEP, UKRAINEJOURNAL OF PETROLEUM GEOLOGY, Issue 4 2004I. Kurovets Middle Miocene (Sarmatian) sandstones in the Ukrainian Carpathian Foredeep are important exploration targets for natural gas. In this paper, we report on petrophysical studies on core samples of these sandstones with which we integrate wireline log data from 42 boreholes. Sarmation siltstones and sandstones in the study area are assigned to the lower part of the Dashava Formation. Seventeen units (LD 17 to LD 1:0.05 to 5m thick) are recognized in this formation on the basis of lithostratigraphy and log response. Sandstone content is highest within three lithostratigraphic complexes corresponding to units LD17-LD14, LD9-LD8 and LD5-LD3. During the Sarmatian, the Carpathian Foredeep was characterized by two depositional systems: a basinal turbidite system, and a second, more mixed system. Important controls on sedimentation included basin configuration and water depth, the occurrence of turbidity and other currents, and the location of provenance areas. Clastic material was delivered to the basin by rivers and ephemeral streams mostly from the Carpathian foldbelt. The content of sandy material within the Sarmatian succession increases from NW to SE, and from the central portion of the Krukenychy depression to the margins of the basin. [source] Micelle-to-vesicle transition induced by oligonucleotide in SDS/DEAB mixed system with a net negative chargeJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2008Xia Guo Abstract Sodium dodecyl sulfate (SDS)/dodecyl triethyl ammonium bromide (DEAB) mixed micelles (with SDS in excess) can transform to vesicles only when the temperature is higher than a critical value. In this study, we report for the first time that oligonucleotide can decrease the critical temperature to a much lower value and, hence, induce micelle-to-vesicle transition. The facilitation efficiency of oligonucleotide on vesicle formation is closely dependent on its size and base composition. Moreover, the SDS/DEAB/oligonucleotide vesicles are negatively charged and the hydrophobic interaction between oligonucleotide and SDS/DEAB mixed micelles is the driving force. As, so far, the report about the facilitation effect of oligonucleotide and DNA on vesicle formation is very limited, this study may provide some helpful information for the application of DNA/amphiphile system. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7491,7504, 2008 [source] RHEOLOGICAL, TEXTURAL AND MICROSTRUCTURE ANALYSIS OF THE HIGH-METHOXY PECTIN/GELATIN MIXED SYSTEMSJOURNAL OF TEXTURE STUDIES, Issue 5 2007H. LIU ABSTRACT The aim of this research was to evaluate the interaction between high-methoxy pectin and gelatin in solution and mixed gel utilizing rheological, texture profile and microstructure analysis. The results showed that the phase separation and association might both exist depending on the ratio of pectin to gelatin in the mixed system. After the pectin addition to the mixed system, the gelation properties of gelatin were improved at suitable conditions. The structure development rate, gel hardness and gel brittleness of the pectin/gelatin mixed system were positively affected by the addition of pectin and from there to expand the application of the mixed system in food industry. PRACTICAL APPLICATIONS Structure-forming polysaccharides and protein provide desired functional properties to a wide range of foods such as gel confectionery products, milk products and fat replacers. As an academic paper, this article provided the information that high-methoxy (HM) pectin could prove the gelation properties of gelatin to corporate audiences. We could find that the ratio of HM pectin to gelatin, and the concentration of these two polymers, dictate the texture properties of the mixed system. The pectin addition to the gelatin system affected the structure development rate, which might save time when the products are processed in practice. The melting temperature was increased with the pectin addition to the gelatin system, which is favorable if it is to be kept under higher temperature. [source] Side Chain Mediated Electronic Contact between a Tetrahydro-4H -thiopyran-4-ylidene-Appended Polythiophene and CdTe Quantum DotsCHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2006Rick van Beek Dr. Abstract The properties of a mixed CdTe quantum dot/tetrahydro-4H -thiopyran-4-ylidene-functionalized polythiophene system are reported. This system was prepared by exposing trioctylphosphine (TOP)-capped CdTe quantum dots to the polythiophene in solution. Strong fluorescence emission quenching and shortening of the fluorescence emission lifetimes of both the polythiophene and the quantum dots occur when they are mixed, indicating the occurrence of photoinduced charge separation. Photoinduced absorption spectroscopy reveals a considerable decrease in the population of the polythiophene triplet excited state in the mixed system. These results demonstrate that between the quantum dots and the polythiophene there is both physical and electronic contact, which is mediated by the tetrahydro-4H -thiopyran-4-ylidene side chains. [source] Interfacial and foaming characteristics of milk whey protein and polysaccharide mixed systemsAICHE JOURNAL, Issue 4 2010Adrián A. Perez Abstract Protein-polysaccharide (PS) interactions find many applications in food engineering and new foam formulations. In this article, we have studied the effect of anionic nonsurface active PSs [sodium alginate (SA) and lambda-carrageenan (,-C)] in aqueous solution on interfacial and foaming characteristics of milk whey proteins [whey protein concentrate (WPC) and whey protein isolate (WPI)]. Whey protein concentration (1.0% wt), temperature (20°C), pH (7), and ionic strength (0.05 M) of the aqueous media were kept constant, while PS influence was evaluated within a 0.0,1.0% wt concentration range. The dynamic properties (dynamics of adsorption and surface dilatational properties) of WPC/PS and WPI/PS adsorbed films were considered in order to correlate the foaming characteristics of the biopolymer mixed systems. Foaming characteristics of the biopolymer mixed systems depended on the PS relative concentration in the aqueous phase and on the whey protein-PS interactions in solution and at the air,water interface. Dynamic surface properties of the adsorbed films at short adsorption time had a significant effect on foaming capacity. For a particular system, the overall foam destabilization (foam half-life time) and the individual destabilization processes (drainage, disproportionation, and bubble coalescence) depend on the nature of the PS, its relative bulk concentration, and whey protein-PS interactions in the vicinity of the air,water interface. The viscosity of the aqueous phase has an effect on the rate of drainage while the rate of disproportionation/collapse is more dependent on the interfacial characteristics of the adsorbed film. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Adsorption and rheological properties of biopolymers at the air-water interfaceAICHE JOURNAL, Issue 7 2006Rosa Baeza Abstract Dynamics of adsorption and viscoelasticity of biopolymers (,-lactoglobulin (,-lg) + polysaccharides (PS)) at 20 °C and pH 7 have been studied. Protein concentration in the bulk phase was 0.1 wt %, and the concentration of polysaccharides (xanthan gum, ,-carrageenan, and propylenglicol alginate with different degrees of esterification and viscosity) was varied from 0.1% to 0.5 wt %. The results reveal a significant effect of surface-active and non surface-active polysaccharides on the dynamics of the formation and viscoelasticity of adsorbed films at the air-water interface. The rate of diffusion of the biopolymers increased in the mixed systems, but the effect was more significant at the highest concentration of polysaccharide (0.5 wt %). The rate of rearrangement of the adsorbed films decreased in the presence of polysaccharides as compared to the protein film. Competitive adsorption, complexation and limited thermodynamic incompatibility between ,-lactoglobulin and polysaccharide would explain the observed effects. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source] A laser imaging and neutron reflection investigation into the monolayer behaviour of fatty acids used for taste masking microspheresJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2008Sheng Qi Abstract Fatty acid microspheres have been used for taste masking purposes whereby the drug is preferentially released in the lower gastrointestinal tract, although the mechanisms involved are poorly understood. In this study, we use a combination of surface pressure measurements, Brewster angle microscopy (BAM) and neutron reflectivity measurements to study the phase miscibility and escaping tendency from mixed stearic and palmitic acid films with a view to relating this to drug dissolution behaviour. It was noted that mixed systems showed considerably greater film interaction and instability than those composed of the pure lipid, especially in alkaline media. BAM studies were able to identify a range of phase separated structures for both the pure and mixed systems. Neutron reflectivity studies indicated a marked selective dissolution of palmitic acid into the subphase as a function of time and allowed quantification of the rate of dissolution of this species. It is concluded that the fatty acids are interacting within the monolayer and in addition the palmitic acid is escaping the mixed monolayers and dissolving into the alkali subphase. These findings have strong relevance for understanding the mechanism of drug release from the associated microspheres. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97: 1864,1877, 2008 [source] A study of phase separation in peptide-loaded HPMC films using Tzero -modulated temperature DSC, atomic force microscopy, and scanning electron microscopyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2004Samana Hussain Abstract Despite the widespread use of drug-loaded polymeric systems, there is still considerable uncertainty with regard to the nature of the distribution of the drug within the polymer matrix. The aim of this investigation was to develop thermal and microscopic techniques whereby the miscibility and spatial distribution of a model peptide, cyclosporin A (CyA), in hydroxypropyl methylcellulose (HPMC) films may be studied. The new technique of Tzero -modulated temperature differential scanning calorimetry (Tzero MTDSC), scanning electron microscopy (SEM), and pulse force mode atomic force microscopy (PFM-AFM) were used in conjunction to study films prepared using a solvent evaporation process, with a solvent extraction study performed to elucidate the nature of the observed phases. Tzero MTDSC studies showed glass transitions for both the HPMC and CycA, with the Tg for the HPMC and CycA seen for the mixed systems. SEM showed two spherical phases of differing electron density. PFM-AFM also showed spheres of differing adhesion that increased in size on addition of drug. Pixel intensity analysis indicated that the smaller spheres corresponded to CycA. Exposure of the films to dichloromethane, in which CycA is soluble but HPMC is not, resulted in the presence of voids that corresponded well to the spheres suggested to correspond to the drug. It was concluded that the system had undergone extensive or complete phase separation, and that the thermal and microscopic techniques outlined above are an effective means by which this issue may be studied. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:1672,1681, 2004 [source] On the application and extension of system signatures in engineering reliabilityNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 4 2008Jorge Navarro Abstract Following a review of the basic ideas in structural reliability, including signature-based representation and preservation theorems for systems whose components have independent and identically distributed (i.i.d.) lifetimes, extensions that apply to the comparison of coherent systems of different sizes, and stochastic mixtures of them, are obtained. It is then shown that these results may be extended to vectors of exchangeable random lifetimes. In particular, for arbitrary systems of sizes m < n with exchangeable component lifetimes, it is shown that the distribution of an m -component system's lifetime can be written as a mixture of the distributions of k -out-of- n systems. When the system has n components, the vector of coefficients in this mixture representation is precisely the signature of the system defined in Samaniego, IEEE Trans Reliabil R,34 (1985) 69,72. These mixture representations are then used to obtain new stochastic ordering properties for coherent or mixed systems of different sizes. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008 [source] Generalized mixtures in reliability modelling: Applications to the construction of bathtub shaped hazard models and the study of systemsAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 3 2009Jorge Navarro Abstract In this paper, we obtain and discuss some general properties of hazard rate (HR) functions constructed via generalized mixtures of two members. These results are applied to determine the shape of generalized mixtures of an increasing hazard rate (IHR) model and an exponential model. In addition, we note that these kind of generalized mixtures can be used to construct bathtub-shaped HR models. As examples, we study in detail two cases: when the IHR model chosen is a linear HR function and when the IHR model is the extended exponential-geometric distribution. Finally, we apply the results and show the utility of generalized mixtures in determining the shape of the HR function of different systems, such as mixed systems or consecutive k -out-of- n systems. Copyright © 2008 John Wiley & Sons, Ltd. [source] From Prague to Baghdad: Lustration Systems and their Political Effects1GOVERNMENT AND OPPOSITION, Issue 3 2006Roman David This article provides a preliminary evaluation of the de-Baathification policy that has been adopted by the occupying forces in Iraq. In order to do this evaluation, the article examines the logic behind major lustration laws approved in East European countries between 1990 and 2003 and assesses their political effects. It introduces the concept of ,lustration systems' and provides their classification into either ,exclusive', ,inclusive', ,reconciliatory' or ,mixed' systems. It recommends a ,reconciliatory' system for the new Iraqi administration as an alternative to the ,mixed' system previously pursued by the Coalition authorities in Iraq. [source] | ||||||||||||||||||||||