Measuring effect of the blooming of chemical curatives on the rate of cyclic fatigue crack growth in natural rubber filled with a silanized silica nanofiller

Two rubber compounds with different amounts of chemical curatives were prepared by mixing natural rubber with a high loading of a sulfur‐bearing silanized precipitated amorphous white silica nanofiller. The chemical bonding between the filler and rubber was optimized via the tetrasulfane groups of the silane by adding a sulfenamide accelerator and zinc oxide. The rubber compounds were cured and stored at ambient temperature for 65 days before they were tested. One compound showed extensive blooming as a function of storage time. Thin tensile strips of the rubber vulcanizates containing an edge crack were repeatedly stressed at constant strain amplitude and test frequency at ambient temperature and crack length c was measured as a function of the number of cycles n. The cut growth per cycle, dc/dn, was calculated and plotted against the tearing energy, T. The blooming of the chemical curatives increased dc/dn by up to an order of magnitude at a constant T. This was due to the reagglomeration of the chemical curatives in the rubber and also within a thin layer approximately 15 to 20 μm in size beneath the rubber surface. Under repeated stressing, cracks grew through the relatively weak agglomerated areas in the rubber and this caused the rate of crack growth to increase at a constant T. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Realization of multigigabit channel equalization and crosstalk cancellation integrated circuits

In this paper, we present integrated circuit solutions that enable high-speed data transmission over legacy systems such as short reach optics and electrical backplanes. These circuits compensate for the most critical signal impairments, intersymbol interference and crosstalk. The finite impulse response (FIR) filter is the cornerstone of our architecture, and in this study we present 5- and 10-Gsym/s FIR filters in 2-/spl mu/m GaAs HBTs and 0.18-/spl mu/m CMOS, respectively. The GaAs FIR filter is used in conjunction with spectrally efficient four-level pulse-amplitude modulation to demonstrate 10-Gb/s data throughput over 150 m of 500 MHz/spl middot/km multimode fiber. The same filter is also used to demonstrate equalization and crosstalk cancellation at 5 Gb/s on legacy backplane. The crosstalk canceller improves the bit error rate by five orders of magnitude. Furthermore, our CMOS FIR filter is tested and demonstrates backplane channel equalization at 10 Gb/s. Finally, building blocks for crosstalk cancellation at 10 Gb/s are implemented in a 0.18-/spl mu/m CMOS process. These circuits will enable 10-Gb/s data rates on legacy systems.     

Direct synthesis of highly crystalline single-phase hexagonal tungsten oxide nanorods by spray pyrolysis

The metastable state hexagonal-tungsten oxide (h-WO₃) has been attracting attention over the past decade because of its high reactivity that arises from the hexagonal channels in its crystal structure. Simplification of the process used to synthesize h-WO₃ is an important step to facilitate the industrial applications of this material. In this study, we addressed this challenge by developing a spray pyrolysis process to synthesize highly crystalline h-WO₃. The ratio of the monoclinic to the hexagonal phase was controlled by adjusting the segregation time. Single-phase h-WO₃ nanorods were synthesized using a carrier gas flow rate of 1?L/min, which was equivalent to a segregation time of 18.4?s. The ability of the h-WO₃ nanorods to adsorb nitrogen and carbon dioxide was evaluated to confirm the presence of hexagonal channels in the crystal structure.     

Aflatoxins: Biosynthesis,Occurrence, Toxicity,and Remedies

Food contagion with aflatoxins is the modern concern and has received a great awareness during the last few decades. The intermittent incidence of these toxins in agricultural commodities has negative role on the economy of the affected regions where harvest and postharvest techniques for the prevention of mold growth, are seldom practiced. Aflatoxins are difuranocoumarin derivatives produced by a polyketide pathway by the fungus Aspergillus flavus and Aspergillus parasiticus via polyketide pathway which are highly hepatotoxic, hepatocarcinogenic, teratogenic, and mutagenic in nature and contaminate a wide variety of important agricultural commodities before, during, and after harvest in various environmental conditions. The production of aflatoxins in innate substrates depends upon the various factors, that is, type of substrate, fungal species, moisture contents of the substrate, minerals, humidity, temperature, and physical damage of the kernels. These toxins cause several ailments such as cancer, hepatitis, mutation abnormalities, and reproduction disorders. Minimization and inactivation of aflatoxins contaminants through proper crop management at farm level and with physical, chemical, and biological techniques are the limelight of the article.     

Breath figure templated semifluorinated block copolymers with tunable surface properties and binding capabilities

Patterning of functionalized polymeric surfaces enables the adjustment of their characteristics and use in novel applications. We prepared breath figure (BF) films from three semifluorinated diblock copolymers, which all are composed of a polystyrene block and a semifluorinated one to compare their surface properties. “Click” chemistry was employed to one of the polymers, containing a poly(pentafluorostyrene) block to incorporate hydrophilic sugar or carboxylic acid moieties. The structure of the polymer alters the obtained porous morphology of the films. Contact angle (CA) analyses of the BF films reveals that the surface porosity increases water CAs compared with solvent cast films, and, in the case of hydrophobic polymers, leads to significant increase in the CAs of dodecane. The hydrophobicity of the BF films is further amplified by the removal of the topmost layer which leads in some cases to superhydrophobic surfaces. BF films containing glucose units are hydrophilic exhibiting water CAs below 90°. These glycosylated porous surfaces are shown to bind lectin Con A‐FITC or can be labelled with isothiocyanate marker. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41225.     

Extrusion processing of green biocomposites: Compounding,fibrillation efficiency,and fiber dispersion

The efficiency of twin‐screw extrusion process to fibrillate cellulose fibers into micro/nanosize in the same step as the compounding of green bionanocomposites of thermoplastic starch (TPS) with 10 wt % fibers was examined. The effect of the processing setup on micro/nanofibrillation and fiber dispersion/distribution in starch was studied using two types of cellulose fibers: bleached wood fibers and TEMPO‐oxidized cellulose fibers. A composite with cellulose nanofibers was prepared to examine the nanofiber distribution and dispersion in the starch and to compare the properties with the composites containing cellulose fibers. Optical microscopy, scanning electron microscopy, and UV/Vis spectroscopy showed that fibers were not nanofibrillated in the extrusion, but good dispersion and distribution of fibers in the starch matrix was obtained. The addition of cellulose fibers enhanced the mechanical properties of the TPS. Moisture uptake study revealed that the material containing TEMPO‐oxidized fibers had higher moisture absorption than the other composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39981.     

Sludge characteristics in anaerobic SBR system producing hydrogen gas

In this study, sludge characteristics of anaerobic sequencing batch reactor (ASBR) were investigated to improve and optimize the efficiency of the system converting starch into biohydrogen. The effect of stratification in settling phase on H2-producing ASBR, which results in settleable and non-settleable sludge, was observed using a batch experiment. It was concluded that specific H2 activity of decanting non-settleable sludge was higher than that of settleable sludge, which may be the reason of low yield in H2-producing ASBR. In addition, effect of settling time on settleable sludge, which is another key operational parameter, was also analysed using another set of batch experiment. Settling time of the sludge was found to be an important parameter in H2-producing ASBR. Specific H2 activity varied inversely with the duration for which settleable microorganisms were contained in settling phase. Microbial species, responsible for H2 activity in each condition, were identified using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis.     

Stabilizing Smoked Salmon (Oncorhynchus gorbuscha) Tissue after Extraction of Oil

ABSTRACT: Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Discarded pink salmon (Oncorhynchus gorbuscha) tissues were preserved using a combination of smoke-processing and acidification with lactic acid bacteria (LAB). All samples were analyzed for moisture, protein, ash, and lipid contents. Bacterial cell counts, pH, and lactic acid concentrations were recorded as a measure of LAB viability. Neither raw nor smoked salmon were free from spoilage during 60 d of storage. Only fermented samples successfully stabilized below pH 4.7, while retaining lactic acid concentrations over 15 g/L during storage. When smoked, fermented salmon head tissues were dried, the pH of the resulting high-protein “cracker” was significantly lower than when crackers were prepared only from the smoked (but not fermented) salmon material. Both cracker varieties retained valuable polyunsaturated fatty acids. This research suggests that salmon-head tissues discarded after oil extraction represent a good source of protein and high-value fatty acids in a shelf-stable form. Practical Application: Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Material produced from salmon tissue discarded after oil extraction may represent a valuable resource for preparing high-protein crackers and other fish-based food products. In addition to providing a unique smoke-flavoring, the smoked, fermented fish material may also impart antioxidant factors thereby extending the shelf life of the product.     

Big Data Analytics Using Graph Signal Processing

The networks are fundamental to our modern world and they appear throughout science and society. Access to a massive amount of data presents a unique opportunity to the researcher’s community. As networks grow in size the complexity increases and our ability to analyze them using the current state of the art is at severe risk of failing to keep pace. Therefore, this paper initiates a discussion on graph signal processing for large-scale data analysis. We first provide a comprehensive overview of core ideas in Graph signal processing (GSP) and their connection to conventional digital signal processing (DSP). We then summarize recent developments in developing basic GSP tools, including methods for graph filtering or graph learning, graph signal, graph Fourier transform (GFT), spectrum, graph frequency, etc. Graph filtering is a basic task that allows for isolating the contribution of individual frequencies and therefore enables the removal of noise. We then consider a graph filter as a model that helps to extend the application of GSP methods to large datasets. To show the suitability and the effeteness, we first created a noisy graph signal and then applied it to the filter. After several rounds of simulation results. We see that the filtered signal appears to be smoother and is closer to the original noise-free distance-based signal. By using this example application, we thoroughly demonstrated that graph filtration is efficient for big data analytics.