Reading urban spaces by the space-syntax method: A proposal for the South Haliç Region

Cities are like living organisms going through constant change and transformations. This condition has demanded the development of suitable and adaptive design solutions that require the full consideration of the spatial continuity of the city, its physical and social peculiarities, user needs, and desire for safe and healthy communities. In addition, architects and designers need to be familiar with the developmental stages of the city, including components that may have disappeared over time. It is therefore necessary to read different segments that constitute the city to reveal its historical, cultural, social, physical and symbolic features.The aim of this study was to implement a methodology: (1) to determine the social and physical problems of a historical urban space and subsequently (2) to offer recommendations that attempt to improve the identified problems. The South Haliç Area in Istanbul was chosen as the case study because of its historical and cultural significance and the importance that should be placed on its preservation for future generations. We relied on the space-syntax methodology to analyze the area and offer a number of design interventions. These recommendations were evaluated using the same methodology to illustrate the degree to which they would improve upon the current conditions.     

Catalyst effect on the transesterification reactions between polycarbonate and polycaprolactone-B-polydimethylsiloxane triblock copolymers

Summary Transesterification reactions between bisphenol-A polycarbonate and polydimethylsiloxane-polycaprolactone block copolymers were studied in melt at 270°C. Influence of the composition of reaction mixture and the catalyst type on the formation and properties of the products obtained were investigated by spectroscopic, chromatographic and thermal methods. Both of the catalysts used, zinc acetate and lanthanum acetylacetonate are very efficient transesterification catalysts for the system studied. GPC and DSC results clearly show the formation of novel polymers displaying combined properties of the polycarbonate and the silicone-ester copolymer. Received: 22 June 1999/Accepted: 8 September 1999     

Controlled synthesis of crosslinked polyamide 6 using a bis-monomer derived from cyclized lysine

The controlled synthesis of polyamide 6 chemical networks by anionic ring-opening copolymerization of ε-caprolactam (CL) with synthesized bis-ε-caprolactam derived from α-amino-ε-caprolactam, i.e. N-functionalized α-amino-ε-caprolactam bis-monomers, using sodium ε-caprolactamate as an initiator and hexamethylene-1,6-dicarbamoylcaprolactam as di-functional fast activator was examined in bulk at 140 °C. An urea-based bis-monomer and CL were first shown to copolymerize with a decreasing polymerization rate due to side reactions. On the contrary, quantitative copolymerization of CL with various amounts of bis-N(2-oxo-3-azepanyl)-1,6-tetramethylenediamide, an amide-based bis-monomer, leads to fast kinetics similar to the homopolymerization of CL. Crosslinked PA6 with network exhibiting elastic or viscoelastic behaviors, depending on the amount of crosslinker, were observed and characterized by swelling in hexafluoroisopropanol, dynamic mechanical analysis and rheology measurements. Crystallinity and swelling were shown to decrease with the increasing content of the crosslinking agent.     

Reactive red 120 and NI(II) derived poly(2‐hydroxyethyl methacrylate) nanoparticles for urease adsorption

Non‐porous poly(2‐hydroxyethyl methacrylate) [p(HEMA)] nanoparticles were prepared by surfactant free emulsion polymerization. The p(HEMA) nanoparticles was about 200 nm diameter, spherical form, and non‐porous. Reactive Red 120 (RR 120) was covalently attached to the p(HEMA) nanoparticles and Ni(II) ions were incorporated to attach dye molecules. Urease was immobilized onto RR120‐Ni(II) attached p(HEMA) nanoparticles via adsorption. The maximum urease adsorption capacity of RR120‐Ni(II) attached p(HEMA) nanoparticles was 480.01 mg g^?1 nanoparticles at pH 7.0 in phosphate buffer. It was observed that urease could be repeatedly adsorbed and desorbed without significant loss in adsorption amount. K_m values were 21.50 and 34.06 mM for the free and adsorbed enzyme. The V_max values were 4 U for the free enzyme and 3.3 U for the adsorbed enzyme. The optimum pH was 25 mM pH 7 phosphate buffer for free and adsorbed enzyme. The optimum temperature was determined at 35°C and 55°C for the free and adsorbed enzyme, respectively. These findings show considerable promise for this material as an adsorption matrix in biotechnological applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39757.     

Impact and post impact behavior of layer fabric composites

In this study, the effect of impact and post impact behavior of E-glass/epoxy composite plates having different layer fabrics were investigated by considering energy profile diagram and the related load–deflection curves. Different impact energies (5 J–60 J)were subjected to the plates consisting of eight layers of plain weave (1D), double (2D) and triple (3D) layer fabrics. The impact tests were continued until complete perforation of layer fabrics. The damage modes and damage processes of layer fabrics under varied impact energies were also discussed. At the end of the impact tests, the damaged samples were mounted into a compression apparatus to determine the Compression After Impact (CAI) strength of layer fabric samples. The results of these impact and post impact tests showed that contact force occurring between the impactor and the composite specimen increased and the CAI strength reduced by increasing the impact energy. The objective of this study was to determine the perforation threshold of E-glass/epoxy composite plates having different layer fabrics as plain weave (1D), double (2D), and triple (3D) layer fabrics.     

Reduction of methomyl and acetamiprid residues from tomatoes after various household washing solutions

The removal of pesticide residues is essential in order to control and reduce the harmful effects of pesticides commonly used in agriculture. The aim of this study was to investigate the effectiveness of 18 different household washing solutions for the reduction of methomyl and acetamiprid residues from tomatoes. These basic household solutions were used to prepare washing solution to remove pesticides. During this study, tomatoes were divided into two groups: in the first group, tomatoes were treated with the pesticides and the second group was washed with household solutions (distilled water, acetic acid, sodium chloride, ethanol, sodium bicarbonate, hydrogen peroxide, sodium hypochlorite, and liquid soap, lemon juice, mineral water, zam-zam water, whey, milk, and their combinations) after treating with pesticides. The pesticides residues in all samples were extracted by the QuEChERS technique, analyzed by LC-MS/MS. The results showed significant reduction in residues of all washed groups compared with the control (p < 0.01). Acetic acid, sodium chloride+sodium bicarbonate, zam-zam water, acetic acid+sodium chloride, sodium hypochlorite, milk, acetic acid+sodium chloride+sodium bicarbonate, liquid whey, liquid soap, lemon juice, ethanol, and sodium bicarbonate were found to remove more than 50% of both pesticide residues. The effectiveness of washing solutions was different for every type of pesticide. In the same way, blend of washing solutions has shown a synergetic effect on the removal of pesticides and was more effective compared to one solution. This research has raised the potential use of household solutions easily found at home that could be used to remove pesticide residues.     

Enzyme‐assisted aqueous extraction of safflower oil: optimisation by response surface methodology

Aqueous enzymatic oil extraction of safflower seeds was assisted by Alcalase 2.5L and Celluclast 1.5L. Enzyme type and amount, pH, time, temperature, churning rate, dilution ratios and particle size were varied to determine their influence on the oil amount. The amount of oil recovered was higher using seeds ground to a particle size of <0.6 mm. Response surface methodology was employed for the optimisation of aqueous enzymatic oil extraction conducted with Celluclast 1.5L. When the extraction was assisted by Celluclast 1.5L, the maximum oil amount and yield were 33.3 (% w/w) and 79.7 (% w/w), respectively. The optimum conditions were 48.3 °C; 0.25 mL enzyme g^?1 substance; pH, 4.84; resulting oil amount and yield were 28.2 (% w/w) 65 (% w/w), respectively. The predicted critical values were experimentally verified, and an oil amount of 27.1 (% w/w) was achieved. The enzyme treatment did not have any determining effect on the physicochemical properties of extracted oil.     

A novel polymer critical re-melting treatment for improving corrosion resistance of magnesium alloy stent

Polymer coating was widely used as a protective coating on Mg alloy stent due to its excellent deformability. However, the polymer coating with lots of macro- and micro-holes after solvent evaporation during forming process would make corrosion medium permeate easier and decrease the corrosion resistance of Mg alloy stent. In this study, a novel critical re-melting method was adopted to improve the polymer coating densification, which was evaluated by the surface morphology of coating. The corrosion resistance of Mg alloy stent after critical re-melting treatment was examined by the electrochemical and immersion tests. The results indicated that the corrosion resistance of Mg alloy stent with polymer coating was improved significantly by polymer critical re-melting treatment.     

Effect of mechanical activation on thermal energy storage properties of Co3O4/CoO system

The heat produced by a solar receiver during on-sun operation can be employed to drive the endothermic reduction reaction of Co₃O₄ to CoO; then the consumed thermal energy can be recovered completely by the exothermic reverse oxidation reaction of CoO to Co₃O₄ which can take place during off-sun operation. In this research, the effect of mechanical activation duration (1, 2, 4, 8, and 16?h) on thermal energy storage by Co₃O₄/CoO redox pair was investigated. It was found that increasing the mechanical activation duration increases the sintering and particle size of the cobalt oxide powder after one cycle redox, and subsequently the thermal energy storage properties are declined. The weight loss was about 4–5?wt.% for samples heated by 1, 3, and 5?$°\text{C}$/min, while it was about 2?wt.% for 10?$°\text{C}$/min heating rate and less than 1?wt.% for 15?$°\text{C}$/min heating rate. The comparison of cycleability of as-received and 1?h mechanical activated cobalt oxide showed that mechanical activation weakens the cycleability of redox reactions of cobalt oxide. The as-received cobalt oxide cycleability continued up to three cycles, although the reduction and oxidation capacities gradually declined. The cycleability of 1?h mechanical activated sample entirely diminished after two cycles.