UV radiation curing of surface coatings based on ENR-cycloaliphatic diepoxide-glycidyl methacrylate system by cationic photoinitiators-optimization of process variables through response surface methodology

This paper reports on the results of the ultraviolet curing of surface coatings based on cycloaliphatic diepoxide-epoxidized natural rubber (ENR)-glycidyl methacrylate (GMA) system with a cationic photoinitiator. The results reported in our earlier publication¹ showed that ENR acts as a toughening agent for the otherwise brittle epoxy resin, and that GMA functions as a crosslinking agent in the system and promotes adhesion between the elastomeric domain and the resin matrix. In this paper, the results of the effect of operating variables on the properties of the cured film are reported. Response surface methodology (RSM) was employed to collect data and to establish the functional relationships between operating variables and performance characteristics of the cured coatings. The data are represented in three-dimensional response surface plots. These plots not only enable the interpretation of results, but also allow the determination of the optimum treatment combinations required to maximize the properties of the surface coatings. Wood Paper and Coatings Div., School of Industrial Technology, 11800 Pulau Pinang, Malaysia.     

Polypropylene Hybrid Composites: A Preliminary Study on the use of Glass and Coconut Fiber as Reinforcements in Polypropylene Composites

Polypropylene hybrid composites were made using coconut and glass fibers as reinforcing agents in the polypropylene matrix. The incorporation of both fibers into the PP matrix has resulted in the reduction of flex-ural, tensile, and impact strengths and elongation at break. The reduction has been attributed to the increased incompatibility between the fibers and the PP matrix, and the irregularity in fiber size, especially for biofibers as shown by scanning electron micrographs. Both the flexural and tensile moduli have been improved with the increasing level of fiber loading. Most of the properties tested for Composites with high glass fibers/low biofiber loading are comparable with the ones with low glass fiber/high biofiber loading. The results show that more biofibers could be incorporated in hybrid composites which would give the same range of properties as the composites with higher loading of glass fibers.     

A double antibody sandwich enzyme-linked immunosorbent assay for the detection of Salmonella using biotinylated monoclonal antibodies

A double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed using monoclonal antibodies (MAbs) as a rapid, economical alternative to culture isolation procedures for detection of Salmonella. Four MAbs previously shown to react with Salmonella strains representing 18 different serogroups were evaluated as capture antibodies and, after biotinylation, as detection antibodies. One MAb (M183) was selected for use in the ELISA to capture and detect Salmonella antigens. The detection limit of the ELISA was evaluated using Salmonella enterica subspecies enterica serovar Typhimurium and various selective and nonselective Salmonella enrichment media. The highest detection limit (ca. 10(4) CFU/ml) was achieved using an enrichment broth containing brain heart infusion, yeast extract, sodium hydrogen selenite, and sodium cholate (BYSC) after preenrichment in buffered peptone water. The ELISA detected all Salmonella serovars tested, which included representative serovars of serogroups B, C, D, and E and gave negative results for all non-Salmonella species tested. Samples (106) from various sources, including fecal samples from humans and pigeons, chicken carcass rinses, chicken parts, feed, and the environment, were used to evaluate the performance of the ELISA. The ELISA had a specificity and sensitivity of 100 and 91%, respectively, and a kappa value of 0.93 relative to the culture methods. Such an ELISA has the potential to be used in the implementation of the pathogen reduction and hazard analysis critical control point systems as well as in clinical laboratories.     

Advances on transition metal oxides catalysts for formaldehyde oxidation: A review

This article highlights recent advances in the development of transition metal-based catalysts for formaldehyde oxidation, particularly the enhancement of their catalytic activity for low-temperature oxidation. Various factors that enhance low-temperature activity are reviewed, such as morphology and tunnel structures, synthesis methods, specific surface area, amount and type of active surface oxygen species, oxidation state, and density of active sites are discussed. In addition, catalyst immobilization for practical air purification, reaction mechanism of formaldehyde oxidation, and the reaction parameters affecting the overall efficiency of the reaction are also reviewed.     

Life cycle assessment and environmental profile evaluation of lead-free piezoelectrics in comparison with lead zirconate titanate

The prohibition of lead in many electronic components and devices due to its toxicity has reinvigorated the race to develop substitutes for lead zirconate titanate (PZT) based mainly on the potassium sodium niobate (KNN) and sodium bismuth titanate (NBT). However, before successful transition from laboratory to market, critical environmental assessment of all aspects of their fabrication and development must be carried out in comparison with PZT. Given the recent findings that KNN is not intrinsically ‘greener’ than PZT, there is a tendency to see NBT as the solution to achieving environmentally lead-free piezoelectrics competitive with PZT. The lower energy consumed by NBT during synthesis results in a lower overall environmental profile compared to both PZT and KNN. However, bismuth and its oxide are mainly the by-product of lead smelting and comparison between NBT and PZT indicates that the environmental profile of bismuth oxide surpasses that of lead oxide across several key indicators, especially climate change, due to additional processing and refining steps which pose extra challenges in metallurgical recovery. Furthermore, bismuth compares unfavourably with lead due to its higher energy cost of recycling. The fact that roughly 90–95% of bismuth is derived as a by-product of lead smelting also constitutes a major concern for future upscaling. As such, NBT and KNN do not offer absolute competitive edge from an environmental perspective in comparison to PZT. The findings in this work have global practical implications for future Restriction of Hazardous Substances (RoHS) legislation for piezoelectric materials and demonstrate the need for a holistic approach to the development of sustainable functional materials.     

Dietary Oil Type and Late Feed Restriction Elicit Synergistic Effects on Growth,Caeca Bacteria,Carcass, Fat Accretion,and Muscle Lipids in Female Broilers

The influence of dietary oil type (OT) and late feed restriction (FR) on growth, caeca bacteria count, carcass, separable fat depots, serum and muscle lipids, and meat quality in broilers is examined. In total, 224, 21-day-old female Arbor acres broilers are randomly allotted to either PN, Unrestricted+50 g kg⁻¹ palm oil (PO); PR, 25%-FR+PO; SN, Unrestricted+50 g kg⁻¹ soybean oil (SO); or SR, 25%-FR+SO for 21 d. The SN and PR birds have the heaviest and lightest body weight gain (BWG), respectively. Feed conversion ratio (FCR) is poorer in the PN birds. Feed-restricted birds have more caeca Lactobacillus and lower Salmonella, serum cholesterol, and triglycerides. Carcass yield is higher in SR birds and lower in PN birds. The FR-OT interaction is significant for muscle lipids and weight of fat depots. The PN birds deposit more abdominal, intramuscular, sartorial, mesentery and neck fats, muscle saturated fatty acids, and C18:1n-9 and lower C18:3n-3 and C20:5n-3 than other birds. Neither OT nor FR affects the pH, color, water holding capacity, and oxidative stability of breast meat. The changes elicited by 25%-FR on BWG, FCR, carcass yield, depot fats, and muscle lipids in female broilers are dependent on dietary OT. Practical Application: Fast growth rate and unrestricted access to feed can predispose broiler chickens to excessive fat accretion, which is counterproductive. Producing high-quality carcasses that meet consumers’ expectation is crucial for sustainable and efficient broiler production. The possible interaction between dietary OT and late quantitative FR in mitigating excessive fat accretion and altering production indices in female broilers is explored. Late quantitative FR reduces BWG, FCR, serum lipids, caeca pH and Salmonella spp. and fat accretion in fat depots, and enhances carcass yield and caeca Lactobacillus spp. However, the impacts are more pronounced in the PO birds than the SO birds. Late FR improves the C18:3n-3 and C18:2n-6 contents in PO meat while reducing the C14:0 and C16:0 contents in SO meat. These findings explicate that dietary OT and late quantitative FR can be synergistically used to mitigate excessive fat accretion and alter growth, caeca microflora, and muscle lipids in broilers.     

Imaging of biomedical data using a multiplicative regularizedcontrast source inversion method

In this paper, the recently developed multiplicative regularized contrast source inversion method is applied to microwave biomedical applications. The inversion method is fully iterative and avoids solving any forward problem in each iterative step. In this way, the inverse scattering problem can efficiently be solved. Moreover, the recently developed multiplicative regularizer allows us to apply the method blindly to experimental data. We demonstrate inversion from experimental data collected by a 2.33-GHz circular microwave scanner using a two-dimensional (2-D) TM polarization measurement setup. Further some results of a feasibility study of the present inversion method to the 2-D TE polarization and the full-vectorial three-dimensional measurement will be presented as well     

A multiplicative regularization approach for deblurring problems

In this work, an iterative inversion algorithm for deblurring and deconvolution is considered. The algorithm is based on the conjugate gradient scheme and uses the so-called weighted L2-norm regularizer to obtain a reliable solution. The regularizer is included as a multiplicative constraint. In this way, the appropriate regularization parameter will be controlled by the optimization process itself. In fact, the misfit in the error in the space of the blurring operator is the regularization parameter. Then, no a priori knowledge on the blurred data or image is needed. If noise is present, the misfit in the error consisting of the blurring operator will remain at a large value during the optimization process; therefore, the weight of the regularization factor will be more significant. Hence, the noise will, at all times, be suppressed in the reconstruction process. Although one may argue that, by including the regularization factor as a multiplicative constraint, the linearity of the problem has been lost, careful analysis shows that, under certain restrictions, no new local minima are introduced. Numerical testing shows that the proposed algorithm works effectively and efficiently in various practical applications.     

Structure-Property Relationship of Cu-Al-Ni-Fe Shape Memory Alloys in Different Quenching Media

This paper presents the effects of heat treatments using various quenching media on the phase transformation parameters and microstructure parameters. The effects of different quenching methods, step-quenched and up-quenched, in various media were evaluated by using differential scanning calorimetry, field emission electron microscopy, energy-dispersive spectrometry, atomic force microscopy, x-ray diffraction, and Vicker’s hardness. The variations of the structure and properties of Cu-Al-Ni-Fe shape memory alloys were linked to the variations of morphology, type, and stabilization of the obtained phase. From the DSC results, the use of ice water as a quenching medium produced the highest transformation temperatures, while a brine solution-quenching medium resulted in the highest change of the entropy and enthalpy. Additionally, it was found that the best grain refinement was observed through the use of an oil-quenching medium, due to its high cooling rate.