Influence of membrane support structure on the efficiency of an iron-modified silica nanofiltration membrane

Inorganic membranes are generally created by depositing a thin film separation (membrane) layer atop a supporting structure in order to provide for the physical durability of the membrane. The separation layer thickness and morphology are normally evaluated to determine their contribution to fluid flow resistance across the membrane. The supporting structure is often ignored, yet can affect the quality of the membrane formed and significantly influence the global efficiency of the membrane module. In this paper, three different support structures are compared and evaluated with respect to the efficiency (rejection and flux) of an iron-modified silica separation layer. The main difference in the supports was the nominal pore size of the surface responsible for facilitating the membrane layer. The pore sizes of the supports investigated were 5, 10, and 20 nm in diameter. It was hypothesized that the largest pore size support would produce a higher water flux. However, this support did not provide an adequate surface for the deposition of a high quality membrane layer. The formation of an intact membrane layer was successfully achieved using the other two support structures. From the results obtained from salt rejection and flux data of these two functional membrane modules, the influence of the support structure on the overall efficiency of the membrane module was assessed. The 10 nm support structure produced a water flux that was 1.6 times greater than that of the 5 nm pore size support, without sacrificing the rejection of the electrolytes studied.     

Prospect of compact afterburners based on metallic microstructures. Design and modelling

Topics in Catalysis - Two types of structured catalytic reactors for CO/NO x /VOC removal are designed, modelled and compared to classic monoliths: short-channel and gauze structures. The designed...     

The botanical integrity of wheat products influences the gastric distention and satiety in healthy subjects

Background  

Maintenance of the botanical integrity of cereal kernels and the addition of acetic acid (as vinegar) in the product or meal has been shown to lower the postprandial blood glucose and insulin response and to increase satiety. However, the mechanism behind the benefits of acetic acid on blood glucose and satiety is not clear. We hypothesized that the gastric emptying rate could be involved. Thus, the aim of this study was to evaluate the possible influence of maintained botanical integrity of cereals and the presence of acetic acid (vinegar) on gastric emptying rate (GER), postprandial blood glucose and satiety.     

Ease of segmenting two- or three-phoneme words in kindergarten: Rime cohesion and vowel salience?

The ability to segment phonemes in words is fundamental for learning to read and spell. In two experiments, kindergartners segmented 2- and 3-phoneme words in an oral task using blank markers. Children segmented vowel–consonant (VC) words (e.g., age) more easily than consonant–vowel (CV) words (e.g., me) and much more easily than consonant–vowel–consonant (CVC) words (e.g., same). The greater ease of segmenting VC over CV words is attributed to the salience of vowels in initial position. The rime-cohesion hypothesis predicted segmentation performance with CVC but not with CV and VC words, indicating that rimes are a structural property of 3- but not 2-phoneme words. A practical implication is that instruction in phoneme segmentation should begin with 2-phoneme words before 3-phoneme words are taught. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sibling relationship, family, and genetic factors in sibling similarity in sexual risk.

Siblings’ risky attitudes toward sex and pregnancy and risky sexual behavior were studied in 1583 dyads from the National Longitudinal Study of Adolescent Health. We tested moderators of the links between 2 siblings’ reports of sexual risk as well as mediators of the links between siblings’ genetic similarity and similarity in their sexual risk. Siblings’ sexual risk reports were correlated, and consistent with social learning predictions, associations were stronger between siblings with close relationships and in same-gender dyads and, to a lesser extent, between more genetically similar siblings and those closer in age. Consistent with behavior genetics’ hypotheses about gene–environment correlations, similarity in family warmth and sibling relationship closeness mediated associations between siblings’ genetic similarity and similarity in their sexual risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

汉方，健康秀发之源

想要拥有一头健康有光泽的秀发是许多人的梦想，然而因为受到空气污染、生活与工作环境的多重压力，以及不良饮食习惯等因素，大多数的人其实无法拥有非常健康的发质。     

Application of a method for the mathematical experimental statistical modeling approach to analyze physical–chemical properties of interpenetrating polymer network of polyurethane and unsaturated polyester

Modern statistical analysis methods were employed to investigate and evaluate the effect of chemical composition on mechanical properties of interpenetrating polymer network (IPN) formulations that had been synthesized of polyurethane and unsaturated polyester resin (cross‐linked with styrene). Experiments run according to the mathematical plan made a basis for empirical models derived from the Sheffe polynomials. The models were utilized to optimize the chemical composition of IPN from the viewpoint of achievable mechanical parameters, to assess changes of those properties over the whole theoretically possible scope of quantitative compositions, and to investigate the effects of individual components and their possible interactions. The findings supported a thesis on complex interactions between polymeric components of IPN; they can be the reason for tangled polyurethane, unsaturated polyester, and linear polystyrene polymer networks, and ultimately they can be responsible for the formation of immiscible phases within the plastics produced. Data were also obtained which make it possible to evaluate potential mechanical properties of synthesized IPN compounds as coating materials and engineering plastics. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1855–1867, 2005     

The swelling behavior of interpenetrating polymer networks composed of polyurethane and unsaturated polyester

The kinetics of swelling and the sorption performance were observed for the polymer compositions with interpenetrating polymer networks made up of polyurethane and unsaturated polyester during their exposure to chlorobenzene at 25°C. It was found that the rates for solvent transport and solvent absorption processes were controlled by the chemical composition of the formulation studied. On the basis of the observed swelling process, parameters could be assessed which were specific for the mass transfer process, i.e., diffusion coefficient, sorption coefficient, and permeability coefficient. Moreover, an attempt was made to evaluate structural parameters that describe topology of the obtained networks. It was found that the increasing share of polyurethane in the composition reduced crosslinking density in the polyester network that resulted in faster diffusion of the solvent and higher sorption capacity for the solvent. The higher the styrene content in the composition, the higher the crosslinking density in the system, and hence the diffusion of solvent and its sorption inside the polymer network was much more difficult. In the scanning electron microscope analysis of samples, which had been subjected to swelling, no leaching was observed for any phase present in the system, despite phase separation for both the components. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3511–3519, 2006     

DEM simulation of the packing structure and wall load in a 2-dimensional silo

The filling and discharge of a two-dimensional wedged-bottom silo holding circular objects was modelled using DEM technique to examine the influence of method of silo filling on distribution of orientations of unit vectors normal to contact points (contact normals) and normal contact forces. It was found that packing structure determined through method of generation of grain bedding significantly influenced distribution of contact normals. Nearly hexagonal network of contact normals was obtained for central filling of silo while sprinkle filling provided higher anisotropy of contact normals. The significance of frictional conditions and number of particles in system on distribution of contact normals was analysed. Increase in number of grains reduced disturbance from boundaries on behaviour of assembly. Distribution of loads on silo bottom obtained in simulation for different wall roughness was found in qualitative agreement with experimental data.