The use of upflow anaerobic filter and AnSBR for wastewater treatment at ambient temperature

This research was carried out in order to study the effect of the temperature and hydraulic retention time (HRT) on the start-up and steady-state performance of upflow anaerobic filter (UAF) and anaerobic sequencing batch reactor (AnSBR). A mixture of synthetic substrate (glucose and sodium acetate) and real municipal wastewater was used as a laboratory substrate. The temperature (in the range 9-23 degrees C) and HRT (in the range 6-46 h) were selected as the most decisive technological parameters for a practical application. Average removal efficiency of COD found for tested anaerobic reactors were 56-88% (AnSBR) and 46-92% (UAF) depending on used temperature and HRTs. Based on the observed results, the use of AnSBR and UAF in practice seems to be a potential technology for (pre)-treatment of wastewater produced by small communities.     

Extraction fractionation of segmented polyurethanes according to composition

Extraction of solid polyester-based segmented polyurethanes by chloroform and its mixtures with an increasing amount of N,N-dimethylformamide is described. Unlike the precipitation in a solvent-nonsolvent system, where fractionation according to the molecular weight dominates, the extraction can resolve the copolymer into fractions differing in the content of diisocyanate units. © 1995 John Wiley & Sons, Inc.     

Application of image analysis method to detection and counting of glass fibers from filter samples

Man-made vitreous fibers (MMVFs) are noncrystalline substances made of glass, rock or slag and are widely used as thermal or acoustic insulation materials. There is continued concern about their potential health impacts and thus, their dosimetry and behavior in the environment still require study using filters to collect fiber samples. After deposition or exposure measurements of MMVFs it is often necessary to analyze the filters with deposited fibers. This task is tedious, time-consuming, and requires skill. Therefore, many researchers have tried to simplify or automatize fiber detection and quantification. This article describes features of our in-house software, which automatically detects and counts fibers in images of filter samples. The image analysis is based on the use of a histogram equalization and an adaptive radial convolution filter that enhances fiber contrast and thus, improves the fiber identification. The accuracy of the software analysis was verified by comparison with manual counting using ordinary phase-contrast microscopy method. The correlation between the methods was very high (coefficient of determination was 0.977). However, there were some discrepancies caused by false identifications, which led to implementation of manual corrective functions.

Copyright © 2016 American Association for Aerosol Research     

Effects of freezing and frozen storage on the microstructure and texture of ewe's milk cheese

Semi-hard ewe's milk cheeses, frozen immediately after manufacture either slowly at –35 °C or rapidly at –80 °C and stored at –20 °C for 4 months were studied for microstructural and textural characteristics during subsequent ripening. Two control groups were used to establish the effect of freezing: the fresh unfrozen cheese and cheese thawed immediately after freezing. Freezing proper did not result in any marked changes in the textural parameters of the cheeses, but considerable changes were found in slowly frozen cheeses after 4 months of frozen storage. Shear strength values were lower in all frozen and stored cheeses, particularly in cheese samples frozen slowly compared to those in the unfrozen control batch. This parameter and firmness values were significantly lower in both slowly and rapidly frozen cheeses at the completion of ripening. Ripening tended to offset differences in elasticity, noticeable in the cheeses during the first 30 days of ripening. Light microscopy and electron microscopy revealed small cracks and ruptures in the cheeses which could not be observed by the naked eye. More extensive damage to the cheese microstructure was found in slowly frozen cheese samples stored frozen for 4 months.     

Numerical simulation of interaction between turbulent flow and a vibrating airfoil

The subject of this paper is the numerical simulation of the interaction of two-dimensional incompressible viscous flow and a vibrating airfoil. A solid elastically supported airfoil with two degrees of freedom, which can rotate around the elastic axis and oscillate in the vertical direction, is considered. The numerical simulation consists of the stabilized finite element treatment of the Reynolds averaged Navier–Stokes (RANS) approach, the use of turbulence models and the solution of the system of ordinary differential equations describing the airfoil motion. The time dependent computational domain and a moving grid are taken into account with the aid of the Arbitrary Lagrangian–Eulerian (ALE) formulation of the Navier–Stokes equations. High Reynolds numbers up to 10⁶ require to use a suitable stabilization of the finite element discretization and the application of a turbulence model. We apply the algebraic turbulence model, which was designed by Baldwin and Lomax and modified by Rostand. The developed technique was tested by the simulation of flow past a flat rigid plate and the computation of pressure distribution around a rotating airfoil with prescribed motion. Finally, the method was applied to the simulation of flow induced airfoil vibrations. This research was supported under the Grant No. IAA200760613 of the Grant Agency of Academy of Sciences of the Czech Republic. The research of M. Feistauer was partly supported by the research project MSM 0021620839 financed by the Ministry of Education of the Czech Republic and the research of L. Dubcová was partly supported by the grant No. 48607 of the Grant Agency of the Charles University. The authors acknowledge the support of these institutions.     

Characterization and Sintering of a Porous Glass-Ceramic in the System Na2O-B2O3-Sc2O3

Clear glasses which included droplet-like microphases were produced when SiO₂ in sodium borosilicate glasses was replaced by Sc₂O₃. Phase separation and/or crystallization occurred after heat treatment. The porous skeleton of leached glasses consisted of hexagonal ScBO₃. The specific surface areas and pore radii are comparable to those of porous SiO₂ glass. The sintering temperature of porous Sc-based material is higher than that of porous SiO₂. Alumina contamination influenced the structure of the porous material.     

Effects of monomer impurities on the emulsion polymerization of chloroprene and properties of polychloroprene. I. Effect of methyl vinyl ketone

The influences of small amounts (up to 2%) of methyl vinyl ketone in chloroprene on properties of polychloroprene and kinetics of the emulsion polymerization of chloroprene with mercaptans as regulators has been studied. Methyl vinyl ketone causes a substantial increase in molecular weight of polymer, which results in increased viscosity, gel formation, lowered plasticity of polymer, deterioration of processability, decreased tensile strength, and high modulus of vulcanizates. Methyl vinyl ketone interferes with the regulation of molecular weight by both primary and tertiary dodecylmercaptan; some differences are due to lower reactivity of tertiary dodecylmercaptan. In the presence of diisopropyl xanthogene disulfide as a molecular weight regulator the polychloroprene properties are not affected by methyl vinyl ketone. All changes in polymer properties have been proved to be caused by the addition reaction of dodecylmercaptan on methyl vinyl ketone, yielding 1-dodecylthiobutan-3-one. This compound itself has no influence on the polymerization of chloroprene. Methyl vinyl ketone has a marked promoting effect on polymerization rates, which accounts for its high reactivity and solubility in the water phase. A fast polymerization of methyl vinyl ketone takes place in the water phase of emulsion polymerization system simultaneously with the reaction of methyl vinyl ketone with dodecylmercaptan.     

Advanced TALSPEAK Separations Using a Malonate Buffer System

The extraction behavior of lanthanides and americium has been evaluated under Advanced TALSPEAK (Trivalent Actinide Lanthanide Separation by Phosphorus-reagent Extraction from Aqueous Komplexes) conditions using malonic acid as the aqueous buffering agent. The extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) was used as an organic phase liquid cation exchanger in n-dodecane diluent, while N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA) served as a selective aqueous holdback reagent. Extractions conducted from malonate media exhibit a pH profile that flattens as the concentration of malonate is increased up to 1.0 M malonate. This relatively flat extraction behavior from pH 2.5–4.0 is reminiscent of previous studies on Advanced TALSPEAK in lactate media. The extraction kinetics with other carboxylic acid buffers as well as the effects of varying HEDTA, HEH[EHP], and malonate concentration are compared.     

Cryogenic grinding of electrospun poly-ε-caprolactone mesh submerged in liquid media

In this paper, the treatment of poly-ε-caprolactone (PCL) nano/micro-mesh system by cryogenic grinding and subsequent characterization of obtained product is described. The PCL nano/micro-mesh layer submerged in appropriate liquid was cryogenically ground and obtained particles were characterized employing mainly laser diffraction and scanning electron microscopy (SEM). In the ground sample, different types of particles (fibrous particles, fibrous fragments, agglomerates with and without an internal fibrous structure, lamellae and nanoparticles) were identified, described and quantified. Parameters of cryogenic grinding (weight of sample, type of liquid medium, and influence of sample storage) were optimized to maximize the yield of particles with desired features. The potential of the system for cell scaffolding was demonstrated by cultivation of 3T3 fibroblasts on the produced microparticles.     

Changing Landscapes,Changing Landscape's Story

Abstract

Visual surrogates have been widely used for solving environment related issues. Researchers now have concern over the validity of surrogates. Human perception is multi-modal (Wohlwill, 1976 Wohlwill, J. F. 1976. “Environmental aesthetics: the environment as a source of affect”. In Human Behavior and Environment: Advances in Theory and Research, Edited by: Altman, I. and Wohlwill, J. F. New York: Plenum Press. [Crossref] , [Google Scholar]; Ittelson, 1973 Ittelson W. Environment and Cognition Seminar Press New York 1973  [Google Scholar]) and motion is an essential aspect in the perceptual process (Gibson, 1979 Gibson, J. J. 1979. The Ecological Approach to Visual Perception, Boston, MA: Houghton Mifflin.  [Google Scholar]). Therefore, a surrogate has to be able to represent the dynamic elements in the environment and more realistically reflect human environmental experience. The purpose of this study was to examine the validity of videos and slides as visual surrogates for representing dynamic environment. The validity of the surrogates was verified by comparing subjects' perceptual responses to on-site and simulated situations. The perceptual assessments included emotional, cognitive, behavioural and preference responses. The results indicated that on-site participants' emotional responses and preferences are significantly stronger than those of video and slide viewers. In addition, on-site participants' and video viewers' cognitive and behavioural responses were significantly higher than those of slide viewers. Overall, the validity of videos and slides for representing waterscapes was not supported.