Response Surface Modeling and Evaluation of the Influence of Deposition Parameters on the Electrolytic Cu-Sn Alloy Powders Production

In this article, the electrodeposition process of Cu-Sn alloy powders from tripolyphosphate (TPP)-based electrolytes was investigated as a function of deposition parameters. The effects of deposition parameters such as current density, electrolyte composition (Cu/Sn mole ratio), mechanical stirring speed, and temperature on the Cu content of alloy powder and cathodic current efficiency were evaluated using the response surface methodology (RSM). The empirical models developed in terms of deposition parameters were found to be statistically adequate to describe the process responses. The study revealed that as far as the copper content was concerned in the alloyed powders, all parameters selected had positive correlations. However, a high stirring speed and low current density led to a greater current efficiency. The morphology and chemical composition of the electrodeposited Cu-Sn alloy powders were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and inductively coupled plasma (ICP) analysis. An SEM analysis showed that the powder morphology was affected considerably by the cathodic current density and stirring speed.     

Thermal insulation enhancement in concretes by adding waste PET and rubber pieces

The relative change in insulation property of the ordinary concrete due to adding polymeric based waste material is experimentally investigated here. The polyethylene (PET) bottle and automobile tire pieces, which can easily be obtained from the environment with almost no cost, are shredded and added into ordinary concrete to examine heat insulation behaviors of specimens. Five different concrete samples (one ordinary concrete, one concrete with scrap rubber pieces and three concretes with waste PET bottle pieces of various geometries) are considered. The adiabatic hot-box technique is used for comparing effective thermal transmittances of these concrete samples. The results reveal that proper addition of selected waste materials into concrete can significantly reduce heat loss or improve thermal insulation performance. The degree of improvement in thermal insulation is found to vary with the added waste material and geometry of shredded-pieces.     

The selection of technology forecasting method using a multi-criteria interval-valued intuitionistic fuzzy group decision making approach

Technological forecasting is a tool for organizations to develop their technology strategies. The quality of forecasting is extremely important for the accuracy of the results and in turn company future. Therefore a proper selection methodology of forecasting technique that considers the characteristics of technology and resources needed such as cost, time is essential. On the other hand, although many forecasting techniques are available, there is a high uncertainty in choosing the most appropriate technique among a set of available techniques. In this paper interval valued intuitionistic fuzzy technique for order preference by similarity to ideal solution (TOPSIS) method is proposed for the solution of technological forecasting technique selection problem. The proposed method includes seven selection criteria and twelve forecasting technique alternatives. The methodology is applied for 3D TV technology. The results revealed that Fisher Pry method is found as the most appropriate method for forecasting since it has the highest closeness coefficient.     

Comparison of thermal comfort properties of single jersey fabrics produced by hollow yarns with different hollowness ratio

In this study, the thermal comfort properties of single jersey fabrics produced by conventional and hollow cotton yarns with different hollowness ratio have been investigated and compared. For this purpose, thermal conductivity, thermal resistance, thermal absorptivity, air permeability and water vapour permeability of core spun, hollow and conventional yarn fabrics were measured and evaluated statistically. It was observed that thermal comfort properties of single jersey fabrics were affected by the yarn structure and the fibre distribution within the yarn. The results showed that hollow yarn fabrics had better thermal comfort properties than that of conventional yarn fabrics. In hollow yarns, as the hollowness ratio increases, air permeability and thermal conductivity of single jersey fabrics decrease but thermal resistance, thermal absorptivity and water vapour permeability increase. Statistical analysis also indicated that the differences between properties of hollow yarn fabrics and conventional yarn fabrics were significant. Furthermore, the yarn hollowness ratio significantly affects thermal comfort properties of single jersey fabrics.     

A systematic comparative study of the efficient co-catalyst-free photocatalytic hydrogen evolution by transition metal oxide nanofibers

The efficiencies of a series of hydrogen evolving catalysts based on metal oxide nanofibers (NiO, Co₃O₄, Mn₃O₄) are investigated for the photocatalytic hydrogen evolution from water without using any co-catalyst under the visible light irradiation by using triethanolamine (TEOA) as an electron donor and Eosin-Y (EY) dye as a photosensitizer. It is found that the photocatalytic hydrogen evolution activities follow the order as: Mn₃O₄<Co₃O₄<NiO (196 μmolg^?1h^?1, 5552 μmolg^?1h^?1, 7757 μmolg^?1h^?1, respectively). Moreover, the catalytic behavior of these nanofibers on the hydrogen production has been also compared to bulk forms of NiO, Co₃O₄ and Mn₃O₄ by producing hydrogen 937 μmolg^?1h^?1, 901 μmolg^?1h^?1 and 135 μmolg^?1h^?1, respectively. The nanofiber structures demonstrated much higher photocatalytic activity than bulk forms due to the effect of the increased surface to volume ratio deduced from the fibrous character. The photocatalytic plausible pathway for the hydrogen production is also discussed.     

A novel nonchemical approach to the expansion of halloysite nanotubes and their uses in chitosan composite hydrogels for broad‐spectrum dye adsorption capacity

A novel method based on cryoscopic expansion of halloysite nanotubes via frozen water molecules entrapped in their lumens and subsequent lyophilization was described. Detailed analyses confirmed that the inner and outer diameters as well as the surface area of the nanotubes could be efficiently increased without disturbing the inherent tubular structure. The benefits of cryo‐expanded nanotubes for the enhancement of chitosan hydrogel performances were discussed. The composite hydrogels, depending on their compositions and morphologies, exhibited significantly enhanced swelling and mechanical properties compared with neat chitosan hydrogel. This effect was even more pronounced in the hydrogels containing cryo‐expanded halloysite nanotubes. Although neat chitosan is a selectively good adsorbent for anionic dyes, in the presence of a small amount of cryo‐expanded halloysite, the resultant composite hydrogel can establish a relatively high adsorption capacity for anionic and cationic dyes as a broad‐spectrum dye adsorbent. POLYM. COMPOS., 37:2770–2781, 2016. © 2015 Society of Plastics Engineers     

Enrichment of Lysophosphatidylcholine in Canola Lysolecithin

Lysophosphatidylcholine (LPC) possesses excellent oil‐in‐water emulsifying properties and health benefits. The objective of this study was to produce an LPC‐enriched fraction from lysolecithin generated during enzymatic degumming of crude canola oil. Three alcohols (methanol, ethanol and isopropanol) were evaluated for their effectiveness at enriching LPC. A 3 × 3 full factorial design was employed to study the effects of two processing parameters (temperature and alcohol/lysolecithin ratio) on three responses (yield and LPC concentration of alcohol soluble fraction, and LPC recovery) with the most effective alcohol. Ethanol was found to be the best solvent to enrich LPC in lysolecithin. An ethanol soluble fraction with more than 50 % LPC was produced. Quadratic models with R² > 0.9 were developed to describe the relationship between the processing parameters and the responses in the 3 × 3 full factorial experiment. Both ethanol soluble fraction yield and LPC recovery increased with increasing temperature and ethanol/lysolecithin ratio. LPC concentration in the ethanol soluble fraction was enhanced with decreasing temperature and ethanol/lysolecithin ratio. According to the analysis, ethanol soluble fractions with LPC concentration higher than 66 % could be obtained at temperatures of 0–40 °C and an ethanol/lysolecithin ratio of 2:1 (v/w).     

Critical assessment of extracellular polymeric substances extraction methods from mixed culture biomass

Extracellular polymeric substances (EPS) have a presumed determinant role in the structure, architecture, strength, filterability, and settling behaviour of microbial solids in biological wastewater treatment processes. Consequently, numerous EPS extraction protocols have recently been published that aim to optimize the trade off between high EPS recovery and low cell lysis. Despite extensive efforts, the obtained results are often contradictory, even when analysing similar biomass samples and using similar experimental conditions, which greatly complicates the selection of an extraction protocol. This study presents a rigorous and critical assessment of existing physical and chemical EPS extraction methods applied to mixed-culture biomass samples (nitrifying, nitritation-anammox, and activated sludge biomass). A novel fluorescence-based method was developed and calibrated to quantify the lysis potential of different EPS extraction protocols. We concluded that commonly used methods to assess cell lysis (DNA concentrations or G6PDH activities in EPS extracts) do not correlate with cell viability. Furthermore, we discovered that the presence of certain chemicals in EPS extracts results in severe underestimation of protein and carbohydrate concentrations by using standard analytical methods. Keeping both maximum EPS extraction yields and minimal biomass lysis as criteria, it was identified a sonication-based extraction method as the best to determine and compare tightly-bound EPS fractions in different biomass samples. Protein was consistently the main EPS component in all analysed samples. However, EPS from nitrifying enrichments was richer in DNA, the activated sludge EPS had a higher content in humic acids and carbohydrates, and the nitritation-anammox EPS, while similar in composition to the nitrifier EPS, had a lower fraction of hydrophobic biopolymers. In general, the easily-extractable EPS fraction was more abundant in carbohydrates and humic substances, while DNA could only be found in tightly bound EPS fractions. In conclusion, the methodology presented herein supports the rational selection of analytical tools and EPS extraction protocols in further EPS characterization studies.     

Nanocrystalline Hf and Ta containing FeCo based alloys for high frequency applications

FeCo based nanocrystalline materials have excellent soft magnetic properties even at high temperature, but are limited to low frequency applications due to their relatively low electrical resistivities, ρ_e, resulting in high eddy current losses. Amorphous alloys of (Fe₈₁Co₁₉)₈₄M₉B₇ where M = (Hf, HfTa, Ta) were prepared by meltspinning and annealed for increasing times at their respective crystallization temperatures. The nanocrystalline alloys had coercivities less than 0.4 Oe and saturation inductions greater than 1 T. The electrical resistivities of the amorphous ribbons were all similar with values of ρ_e ? 180 μΩ cm. After annealing at the crystallization temperature, the M = Ta alloy had the largest ρ_e of 140 ± 3 μΩ cm. The Ta alloy also had the best high frequency properties, with an initial permeability of 822 at 1 MHz.