Block polymers from poly(ethylene oxide) and styrene

Block copolymers containing poly(ethylene oxide) and polystyrene segments were synthesised via chemical reactions. A step-wise procedure was first employed to prepare peroxycarbamates which were later used to initiate free radical polymerization of styrene at elevated temperatures. In some runs the polymerization temperature and time were programmed. Styrene contents, molecular weights, elastic modulus—temperature relationships, impact strengths and stress—strain behaviour of the copolymers were determined.     

The behavior of organic components in copper recovery from electroless plating bath effluents using 3D electrode systems

An electrochemical method was applied for the recovery of copper both from the spent solutions and from the rinse waters of electroless copper plating baths, containing copper sulfate, formaldehyde, quadrol, and NaOH. Experiments were conducted in a rotating packed cell (Rollschichtzelle) to investigate the effects of current density, electrolyte composition, temperature, and pH on the copper recovery. All the copper (final CCu=0.1 ppm) was recovered from the waste and rinse waters of chemical copper plating plants with 70% current efficiency by the electrochemical treatment in a rotating packed cell at 130 A/m2 current density, room temperature, with 5mm diameter cathode granules, with the presence of formaldehyde, and with a specific energy consumption of 3.2-3.5 kW h/kg Cu. On the other hand, final copper concentrations of 5 ppm were reached with 62% current efficiency and 5.5-5.8 kW h/kg Cu specific energy consumption, with electrolytes containing no formaldehyde.     

Influence of different outdoor design conditions on design cooling load and design capacities of air conditioning equipments

Outdoor design conditions are important parameters for energy efficiency of buildings. The result of incorrect selection of outdoor design conditions can be dramatic in view of comfort and energy consumption. In this study, the influence of different outdoor design conditions on air conditioning systems is investigated. For this purpose, cooling loads and capacities of air conditioning equipments for a sample building located in Adana, Turkey are calculated using different outdoor design conditions recommended by ASHRAE, the current design data used in Turkey and the daily maximum dry and wet bulb temperatures of July 21st, which is generally accepted as the design day. The cooling coil capacities obtained from the different outdoor design conditions considered in this study are compared with each other. The cost analysis of air conditioning systems is also performed. It is seen that the selection of outdoor design conditions is a very critical step in calculation of the building cooling loads and design capacities of air conditioning equipments.     

Effects of the γ-irradiation strength and basalt additive content on the mechanical performance and dielectric response of polypropylene films

In this study, we investigated the effects of high-dose γ-ray irradiation on the mechanical and dielectric properties of polypropylene (PP)–basalt thick films. PP–basalt thick-film composites with various basalt contents from 0.5 to 10.0% were prepared by a hot-press method. The samples were exposed to γ radiation at different doses in the range 3–25 kGy. The mechanical properties of the samples, such as the Young's modulus, tensile strength, percentage strain at break, and energy at break, were examined in the context of the γ-irradiation process. Although the maximum elasticity was obtained for the unirradiated 0.5% basalt-added composite, the 6 kGy γ-irradiated PP–1.0% basalt sample exhibited the highest elasticity properties among all of the composites. The best mechanical properties, including the ultimate tensile strength and energy at break values, were achieved for the 12 kGy γ-irradiated neat PP. The dielectric properties of the PP–basalt composites were also investigated in the 100 Hz to 15 MHz frequency region at room temperature. According to the analysis of the dielectric properties, the 3 kGy γ-irradiated neat PP may have potential for microelectronic device applications that require low dielectric constant and dielectric loss materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47414.     

Photocatalytic degradation of methylene blue with Co alloyed CdZnS nanoparticles

In our present study, firstly; cadmium zinc sulfide (CdZnS) nanoparticles (NPs) with 1, 2, 5, 10% of Zn concentration were synthesized in aqueous solution by simple chemical co-precipitation method and their photocatalytic activity was investigated using the degradation of methylene blue under visible light in air at room temperature. It was found that CdZnS NPs with 2% of Zn concentration indicates the highest degradation efficiency compare to other Zn concentrations. CdZnS NPs with 2% of Zn concentration was symbolized as CdZnS_1. Later; 0.1, 0.2, 0.5, 1, 5, 10% of cobalt (Co) concentration was separately alloyed on the CdZnS_1 NPs. It was oberved that Co(5%):CdZnS NPs has the highest degradation efficiency. Structure, surface morphology, elemental analysis and optical properties of CdZnS_1 and Co (5%): CdZnS NPs 0were analyzed using X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and UV–Vis absorption measurements, respectively. The results showed that Co doped CdZnS NPs can be employed as capable materials to ehance the photocatalytic activity.     

Photon energy absorption parameters for composite mixtures with boron compounds

Boron compounds that are used in the manufacturing of a variety of products are introduced to the environment in the form of waste. The radiation shielding measurements of mixtures that contain boron compounds is considered to be a topic of concern. The mass attenuation coefficients of (PbO and K₂B₄O₇⋅4H₂O) and (PbO and H₃BO₃) as functions of their changing contents have been measured in the X-ray energy range from 25.191 to 57.903 keV. These values are used to determine the effective atomic number of mixtures. The γ-rays emitted from an Am²⁴¹ annular source have been sent to secondary sources whose characteristic X-rays have been used for transmission arrangement. The characteristic X-rays of the secondary sources have been counted by a Si(Li) detector with a resolution of 149 eV at 5.9 keV. Also, the total effective atomic number of each mixture was determined by using the mixture rule. The measured values were compared with theoretically calculated values.     

Process simulation and analysis of a five‐step copper–chlorine thermochemical water decomposition cycle for sustainable hydrogen production

A process model of a five‐step copper–chlorine (Cu–Cl) cycle is developed and simulated with the Aspen Plus simulation code. Energy and mass balances, stream flows and properties, heat exchanger duties, and shaft work are determined. The primary reactions of the five‐step Cu–Cl cycle are assessed in terms of varying operating and design parameters. A sensitivity analysis is performed to examine the effect of parameter variations on other variables, in part to assist optimization efforts. For each cycle step, reaction heat variations with such parameters as process temperature are described quantitatively. The energy efficiency of the five‐step Cu–Cl thermochemical cycle is found to be 44% on the basis of the lower heating value of hydrogen, and a parametric study of potential efficiency improvement measures is presented. Copyright © 2014 John Wiley & Sons, Ltd.