33 research outputs found
Glocal Istanbul?
No full textIstanbul groeide de afgelopen vijfentwintig jaar van 3 naar 13 miljoen inwoners, de historische stad werd een megaregio. Het verstedelijkingproces verliep chaotisch, in de periferie en buiten het zicht van stadsbestuur en planners. De invloed van de globalisering laat zich daarbij nadrukkelijk gelden in het economisch sterk groeiende Turkije. In een hoog tempo kleedt Istanbul zich als een echte Global City, vergelijkbaar met Dubai, Sao Paolo of Shanghai. Met als gevaar dat over honderd jaar niemand meer het verschil ziet tussen deze steden. Of is er hoop en weten de Turken de eigenheid van Istanbul te bewaren?UrbanismArchitecture and The Built Environmen
Dissimilarity is used as evidence of category membership in multidimensional perceptual categorization: a test of the similarity-dissimilarity generalized context model
No full textIn exemplar models of categorization, the similarity between an exemplar and category members constitutes evidence that the exemplar belongs to the category. We test the possibility that the dissimilarity to members of competing categories also contributes to this evidence. Data were collected from two 2-dimensional perceptual categorization experiments, one with lines varying in orientation and length and the other with coloured patches varying in saturation and brightness. Model fits of the similarity-dissimilarity generalized context model were used to compare a model where only similarity was used with a model where both similarity and dissimilarity were used. For the majority of participants the similarity-dissimilarity model provided both a significantly better fit and better generalization, suggesting that people do also use dissimilarity as evidence
Effects of the post-modification using bismuth chelate (BisBAL) on the anti-biofouling and performance properties of flat-sheet microfiltration membranes
No full textMembrane biofouling defined as the attachment and growth of microorganisms on a membrane surface has been a major problem of membrane bioreactor (MBR) technology. The anti-biofouling properties like the inhibition of bacterial adhesion of a membrane are quite significant for a long-term MBR operation. Surface modification is thought to be one of the most common approaches to improve this property. In this study, polymeric microfiltration membranes were modified by adsorption BisBAL, which is a synthesized chelate using bismuth and have a high anti-bacterial effect on various microorganisms, on the membrane surface using dip coating (DC), spin coating (SC), and low pressure-treated coating (LPtC). The purpose was to increase the surface hydrophilicity, change the surface charge, and gain the surface an anti-bacterial characteristic. It was found that the higher adsorption time, lower feed flow rate and higher spinning velocity, and pressure application increased the efficiency of the process during DC, SC, and LPtC, respectively. Furthermore, improved strategies allow the adsorption of BisBAL on the membrane surface and modified membranes has strong resistance to biofouling. Since modification resulted in a decrease in pore fouling and irreversible fouling for all type of membranes, these membranes can be novel alternatives for energy-saving MBR operation
Biomimetic Approaches for Membrane Technologies
No full textMembrane technology is the dominant process in water treatment. However, the operation cost of membranes cannot be decreased unless the amount of fouling, the "Achilles heel" of membranes, and energy consumed are cut. The high energy requirements in commercial nanofiltration, reverse osmosis and forward osmosis technologies lead researchers to develop new membrane designs having high flux values with high salt rejection values. The purpose of this review is to present the inadequacies of the membrane processes by considering studies related to fouling and energy minimization. In this respect, lipid bilayers, block copolymers, aquaporin Z proteins and aligned carbon nanotubes can be the base to build biomimetic membranes. Such studies are summarized due to their remarkable properties in fouling control. Furthermore, the review describes the membrane design strategies and points the limitations hindering commercialization. Additionally, it is hoped that this review will trigger further needed studies
Hollow fiber nanofiltration membranes: A comparative review of interfacial polymerization and phase inversion fabrication methods
No full textNanofiltration membranes for salt and dye filtration: effect of membrane properties on performances
No full textIn this study, commercial nanofiltration membranes (Toray, NF 270, Desal 5 L) were characterized by FT-IR spectroscopy, scanning electron microscope, optical profilometry, contact angle, mechanical strength and zeta potential measurements. Filtration performance tests were conducted with distilled water, MgSO4 solution and synthetic dye solutions, respectively. Among three commercial membranes, Toray membrane was thought to be better one. Additional experiments have been carried out for a more detailed characterization of the selected membrane. Therefore, firstly, flux and removal efficiency was monitored by using dye solutions at different pH values, and then experiments were carried out to observe the effect of different temperatures. Also, another filtration test with NaCl solution were performed for Toray membrane. As the main purpose of this study, it was aimed to establish a significant correlation between the structural properties of membranes and their performances. In the light of the results obtained, it has been observed that the contact angle, mechanical strength and surface roughness values of the membrane significantly affect the membrane performance. It was concluded that the most important parameter in dye removal is the zeta potential. As a result of this work, a data set of commercial membranes were created available to all membrane users
Effect of wetting agent on the dye filtration performance of ultrafiltration membrane
No full textIn this study, the wet phase inversion method was used for fabrication of the flat sheet ultrafiltration (UF) membranes. Three different polymer types and two different wetting agents were used for the fabrication. The effect of polymer types and wetting agents were investigated on the structural and dye performance of casted membranes. Two different synthetic dyes, 100 ppm Setazol Red and 100 ppm Setazol Blue, were used for the performance test. Viscosity, contact angle, and molecular weight cut off (MWCO) of casted membranes were measured and an electro kinetic analyzer, dynamic mechanical analyzer (DMA) and scanning electron microscope (SEM) were used to determine the structural properties. While the highest water and dye permeability were obtained with PES-PEG membrane, PSf-plain membrane gave the highest removal efficiency for Setazol Red and Setazol Blue dyes, which was found to be 78.33% and 82.52%, respectively, in the conditions of neutral pH and ambient temperature. Addition of PVP and PEG wetting agents improved the structural properties and permeability of membranes, but the dye removal was decreased as against plain ones. As the retention of PEG and PVP-based PSf and PES membrane was calculated at an average of 50%, they could be used for dye retention separately or could be a candidate as a pretreatment membrane prior to nanofiltration or reverse osmosis to make their lifetime longer
Foulant and chemical cleaning analysis of ultrafiltration membrane used in landfill leachate treatment
No full textProgress on reinforced braided hollow fiber membranes in separation technologies: A review
No full textAdvantages of hollow fiber membranes include high specific area, possibility of back flushing, and lower pretreatment and maintenance requirements. Aggressive back flushing or airflow, however, can damage hollow fibers. Reinforced braided hollow fibers offer a solution for increasing mechanical strength and extending useful lifetime of hollow fiber membranes. The present review discusses the effects of support layer, spinneret design, polymer type and production speed on properties of reinforced braided hollow fiber membranes. The review concludes with a summary of applications enabled by such mechanical reinforcement
Op hùn plaats? Deelrapport 6: Allochtonen en moeilijk verhuurbare woningcomplexen in Spijkenisse
No full textDe huisvesting van allochtonen geniet al geruime tijd de belangstelling van beleidsmedewerkers, belangengroepen en politici. Achterstand en achterstelling dient bestreden te worden, zo luidt het devies. Deze studie naar de huisvestingssituatie an Turken, Marokkanen, Surinamers en Antillianen gedurende de jaren tachtig, werpt een nieuw ligt op dit onderwerp. In een zestal gemeenten, te weten Breda, Dordrecht, Helmond, Nijmegen, Rotterdam en Spijkenisse, is onderzocht in hoeverre de huisvestingssituatie van deze groep allochtonen gewijzigd is. Wonen ze nu op de plaats van hun keuze, of zijn ze geplaatst? Verklaringen op wijkniveau zijn onderzocht in de verhouding tussen vraag en aanbod op de woningmarkt en in het proces van de woningdistributie. Op complexniveau spelen de beheerstrategieen en het inplaatsingsbeleid van de verschillende sociale verhuurders een belangrijke rol, zeker wanneer het gaat om moeilijk verhuurbare complexen. De resultaten van dit onderzoek tonen aan dat vele allochtonen nog lang niet op hun plaats wonen en dat hun huisvestingssituatie nog onvermindert aandacht behoeft. Het rapport is dan ook vooral bedoelt voor diegenen die beleidsmatig betrokken zijn bij de huisvestingssituatie van allochtonen.Real Estate & HousingArchitectur
