Effects of Filler Loading and Different Preparation Methods on Properties of Cassava Starch/Natural Rubber Composites

Cassava starch-filled natural rubber (NR) composites were prepared by using direct blending and co-coagulation method. The effects of two different method and cassava starch loading on morphology, mechanical properties and thermal properties of cassava starch/NR composites were studied. X-ray diffraction results and scanning electron microscopy images proved that co-coagulation method promotes better dispersion of cassava starch than direct blending method. The composites prepared by co-coagulation method exhibited higher values of tensile strength, tear strength, hardness, and thermal stability. The optimum value of tensile strength and tear strength of cassava starch/NR composites were achieved at a 10 phr cassava starch loading.     

Effects of the structures of end groups of pendant polydimethylsiloxane attached to a polyurethane copolymer on the low temperature toughness

End groups with different structures were grafted to polyurethane (PU) using poly(dimethylsiloxane) (PDMS) as a spacer. The low‐temperature toughness of the PUs was tested at ?30°C, and the structure selectivities of the end groups for low‐temperature toughness were compared. The PDMS functioned as a flexible linker that connected the end groups to the PUs. The tensile strength of the PU generally improved despite the grafting of PDMS and end groups. The conventional shape recovery ratio at 45°C remained greater than 90%, regardless of the content and structure of PDMS and the end group. The PU that contained an adamantyl group (cubic) or a naphthyl group (planar rectangle) showed instant recovery, even at ?30°C, but the PU that contained a phenyl (planar square) or phenoxyphenyl (bent squares) group required warming to 0°C for a similar degree of recovery but showed improvement over a linear PU without any end group. The characteristic structure of the end group was responsible for the selective low‐temperature toughness. The low‐temperature toughness results and the thermal and mechanical properties of the PUs are discussed. POLYM. ENG. SCI., 55:1931–1940, 2015. © 2014 Society of Plastics Engineers     

Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers

Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli (E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.     

Micro grooving simulation and optimization in the roughing stage

The micro pattern machining on the surface of a wide mold is not easily simulated and optimized using conventional methods. This paper represents the micro pattern cutting simulation software. The software simulates micro pattern grooving in 3D geometry, predicts the cutting force and optimizes the time factor in the roughing stage. The v-groove for prism and pyramid patterns and the rectangular groove for rectangular and pillar patterns are simulated. The code of this program is built using visual C++ and OpenGL.     

Development of a Method to Produce Freeze-Dried Cubes from 3 Pacific Salmon Species

Abstract: Freeze-dried boneless skinless cubes of pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum (Oncorhynchus keta) salmon were prepared and physical properties evaluated. To minimize freeze-drying time, the kinetics of dehydration and processing yields were investigated. The physical characteristics of the final product including bulk density, shrinkage, hardness, color, and rehydration kinetics were determined. Results showed that freeze-dried salmon cubes from each of the 3 Pacific salmon species can be produced with a moisture content of less that 10% and a_w less 0.4 and freeze-drying time of 9 h. Processing yields ranged from 26% to 28.4%, depending on fish species. Shrinkage was less than 12% and rehydration of freeze-dried cubes was rapid. The value-added products developed have the potential to be utilized as ingredients for ready-to-eat soups, as snack food, salad topping, and baby finger-food. Practical Application: Freeze-drying removes water from food products without heating them; therefore, this type of drying process yields very high-quality dried foods. In this study, a freeze-dry process was established to produce small cubes of Alaska pink, sockeye, and chum salmon. The goals were to shorten typical freeze-drying time while producing acceptable product characteristics. The freeze-drying process developed took only 9 h to remove about 97% of the moisture of diced Pacific salmon fillets. The freeze-dried salmon cubes produced can be used as ingredients for dehydrated ready-to-eat soups, as baby finger-foods, or as salad toppings.     

Fabrication of zinc-based coordination polymer nanocubes and post-modification through copper decoration

Coordination polymer particles (CPPs) with a high degree of porosity and multi-functional reaction sites are promising for diverse applications. The integration of open sites favorable for the post-modification of CPPs presents a unique opportunity for the rational design of inorganic materials with target-oriented functions. Herein, we report a shape-controllable synthetic protocol for zinc-based coordination polymer nanocubes (Zn-CPNs). In the synthesis, 2,6-bis[(4-carboxyanilino)carbonyl] pyridine ([N3]) ligand is employed as an efficient shape-directing modulator to control the size and shape of Zn-CPNs. More importantly, the [N3] ligand provides metal binding sites suitable for the decoration of other functional metals such as copper ions. The copper-modified Zn-CPNs (Cu_Zn-CPNs) show good activities in a heterogeneous catalytic reaction.

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Solving high‐order partial differential equations with indirect radial basis function networks

This paper reports a new numerical method based on radial basis function networks (RBFNs) for solving high‐order partial differential equations (PDEs). The variables and their derivatives in the governing equations are represented by integrated RBFNs. The use of integration in constructing neural networks allows the straightforward implementation of multiple boundary conditions and the accurate approximation of high‐order derivatives. The proposed RBFN method is verified successfully through the solution of thin‐plate bending and viscous flow problems which are governed by biharmonic equations. For thermally driven cavity flows, the solutions are obtained up to a high Rayleigh number of 10⁷. Copyright © 2005 John Wiley & Sons, Ltd.     

Characterizations of high resistivity TiNxOy thin films for applications in thin film resistors

We report about developing high resistivity thin film resistors using titanium oxy-nitride. Titanium nitride films of different thicknesses ranging from 50 to 300 nm were deposited on SiO₂/Si substrates using the reactive magnetron sputtering method. After deposition, these films were annealed in the air ambient. The structural and electrical properties of the films were examined as a function of annealing temperature. The samples with various thicknesses show TiN(1 1 1) phase. The sheet resistance increases from 150 up to 420 Ω/□ when the film thickness decreases from 300 to 50 nm. Temperature coefficience of resistance (TCR) of the films significantly decreased with decreasing the film thickness. The TCR of 50-nm thick film is quite low, about 49 ppm/K.     

Function of Lipid Storage Droplet 1 (Lsd1) in Wing Development of Drosophila melanogaster

Perilipins are evolutionarily conserved from Drosophila to humans, the lipid storage droplet 1 (Lsd1) is a Drosophila homolog of human perilipin 1. The function of Lsd1 as a regulator of lipolysis in Drosophila has been demonstrated, as the Lsd1 mutant causes an increase of lipid droplet size. However, the functions of this gene during development are still under investigation. In order to determine the function of Lsd1 during development, Lsd1 was knocked down in Drosophila using the GAL4-UAS system. Selective knockdown of Lsd1 in the dorsal wing disc caused an atrophied wing phenotype. The generation of reactive oxygen species in the wing pouch compartment of the Lsd1-knockdown flies was significantly higher than in the control. Immunostaining with caspase-3 antibody revealed a greater number of apoptotic cells in Lsd1-knockdown wing discs than in the control. Cell death by autophagy was also induced in the knockdown flies. Moreover, cells deprived of Lsd1 showed mitochondrial expansion and decreased ATP levels. These results strongly suggest that knockdown of Lsd1 induces mitochondrial stress and the production of reactive oxygen species that result in cell death, via apoptosis and the autophagy pathway. These results highlight the roles of Drosophila Lsd1 during wing development.     

Lateral flexible linking of polyurethane copolymer and the effect on shape recovery and tensile mechanical properties

Shape memory polyurethane (SMPU), flexibly crosslinked via a polyethyleneglycol (PEG) spacer attached to its side through an allophanate group, was tested for shape memory and compared with a linear SMPU. The new SMPU was composed of 4,4′‐methylenebis(phenylisocyanate) (MDI), poly(tetramethyleneglycol) (PTMG‐2000), and 1,4‐butanediol (BD), and included polyethyleneglycol (PEG‐200) as a spacer. A second MDI, linked to the carbamate group of the first MDI, served as the connecting point for the PEG‐200. Two types of SMPU, differing according to their soft segment (PTMG‐2000) and linker (PEG‐200) contents, were compared in mechanical and shape memory properties. In the best case, a 780% increase in maximum stress was attained without any sacrifice in strain for the new material compared with the linear polymer. In particular, the stress–strain curve showed that the PEG‐crosslinked SMPU had superior tensile mechanical properties. Its shape recovery was as high as 99%, which is the best value we have measured for an SMPU. After four cyclic tests, shape recovery remained greater than 95%. Shape retention of the best SMPU remained above 93% even after four cyclic tests. Here, results demonstrating the extraordinary shape memory properties of these types of SMPU, together with differential scanning calorimetry (DSC) and infrared spectroscopy data, are analyzed and discussed. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers