Analyzing the nanoindentation response of carbon black filled elastomers

Carbon black (CB) filled elastomers are structurally complex materials that offer unique properties at different length scales. They have tremendous potential applications in a number of fields including the automotive and aerospace industries and for designing innovative smart materials such as artificial muscles but their applications remain limited primarily due to inadequate understanding of their unique mechanical properties. Here, using the Berkovich technique to probe the surface mechanical properties at different scales the nanoindentation response of a series of composites made by homogeneously dispersed CB nanoparticles inside a semicrystalline copolymer matrix has been explored. While the measured loading part of the force–displacement curves is well described by Meyer's empirical power relation, the inverted methodology (IM) approach to deal with the unloading part has been considered and its outcome has been compared with that obtained from the standard Oliver–Pharr's method. The results were consistent with the observed increase of hardness when the applied displacement decreases for all composite samples over a large range of CB volume fraction. Zhang and Xu's model is demonstrated to produce experimentally consistent explanation of this indentation size effect. X-ray photoelectron spectroscopy (XPS) spectra also show composition gradients with depth up to 100 nm. Furthermore, the effect of CB content, surface features, and length scale-dependent deformation on the hardness–displacement behavior have been considered. These findings highlight the possibility of attaining a diverse set of mechanical properties by a better understanding of the nanoindentation response of CB filled elastomers which can be useful for material selection and design improvements in a number of practical applications.     

Use of Zebrafish Embryo Assay to Evaluate Toxicity and Safety of Bioreactor-Grown Exopolysaccharides and Endopolysaccharides from European Ganoderma applanatum Mycelium for Future Aquaculture Applications

Natural mycelial exopolysaccharide (EPS) and endopolysaccharide (ENS) extracted from bioreactor-cultivated European Ganoderma applanatum mushrooms are of potential high commercial value for both food and adjacent biopharmaceutical industries. In order to evaluate their potential toxicity for aquaculture application, both EPS (0.01–10 mg/mL) and ENS (0.01–10 mg/mL) extracts were tested for Zebrafish Embryo Toxicity (ZFET); early development effects on Zebrafish Embryos (ZE) were also analyzed between 24 and 120 h post-fertilization (HPF). Both EPS and ENS are considered non-toxic with LC₅₀ of 1.41 mg/mL and 0.87 mg/mL respectively. Both EPS and ENS did not delay hatching and teratogenic defect towards ZE with <1.0 mg/mL, respectively. No significant changes in the ZE heart rate were detected following treatment with the two compounds tested (EPS: 0.01–10 mg/mL: 176.44 ± 0.77 beats/min and ENS: 0.01–10 mg/mL: 148.44 ± 17.75 beats/min) compared to normal ZE (120–180 beats/min). These initial findings support future pre-clinical trials in adult fish models with view to safely using EPS and ENS as potential feed supplements for supplements for development of the aquaculture industry.     

In Silico/In Vitro Hit-to-Lead Methodology Yields SMYD3 Inhibitor That Eliminates Unrestrained Proliferation of Breast Carcinoma Cells

SMYD3 is a lysine methyltransferase that regulates the expression of over 80 genes and is required for the uncontrolled proliferation of most breast, colorectal, and hepatocellular carcinomas. The elimination of SMYD3 restores normal expression patterns of these genes and halts aberrant cell proliferation, making it a promising target for small molecule inhibition. In this study, we sought to establish a proof of concept for our in silico/in vitro hit-to-lead enzyme inhibitor development platform and to identify a lead small molecule candidate for SMYD3 inhibition. We used Schrodinger^® software to screen libraries of small molecules in silico and the five compounds with the greatest predicted binding affinity within the SMYD3 binding pocket were purchased and assessed in vitro in direct binding assays and in breast cancer cell lines. We have confirmed the ability of one of these inhibitors, Inhibitor-4, to restore normal rates of cell proliferation, arrest the cell cycle, and induce apoptosis in breast cancer cells without affecting wildtype cell behavior. Our results provide a proof of concept for this fast and affordable small molecule hit-to-lead methodology as well as a promising candidate small molecule SMYD3 inhibitor for the treatment of human cancer.     

Understanding the Corrosion Inhibition Mechanism of Mild Steel in Hydrochloric Acid by a Triazole Derivative: A Combined Experimental and Theoretical Approach

Protection of Metals and Physical Chemistry of Surfaces - The effect of an heterocycle triazole, namely (1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl)methanol (MTM) on the corrosion of mild steel in...     

Vital parameters for high gamma-aminobutyric acid (GABA) production by an industrial soy sauce koji Aspergillus oryzae NSK in submerged-liquid fermentation

Food Science and Biotechnology - In submerged-liquid fermentation, seven key parameters were assessed using one-factor-at-a-time to obtain the highest GABA yield using an industrial soy sauce koji...     

PEC thermography for imaging multiple cracks from rolling contact fatigue

With the development and operation of high speed trains, condition based maintenance becomes an important approach for the improvement of reliability and safety of rail transportation. This paper reports a feasibility study using pulsed eddy current thermography for imaging multiple cracks caused by rolling contact fatigue (RCF). After reviewing rail track inspection and RCF cracks, a PEC thermography system is introduced and applied to the imaging of multiple rolling contact fatigue cracks. Potential on-line inspection for rail track is also discussed.     

Evaluating Land Surface Changes of Makassar City Using DInSAR and Landsat Thematic Mapper Images

Urban growth has been a major issue in environmental monitoring and changes occurred on land surfaces have been monitored by applying remote sensing as well as ground measurement. Most major cities in the world have experienced land subsidence phenomena on some parts of them due to the load of development and modernization. Excessive extraction of groundwater for the needs of industry has led to the condition where the water table drops, and this can possibly trigger subsidence, as observed in Indonesian cities. In this study the authors have shown that the application of DInSAR （differential interferometric synthetic aperture radar） technique using Japanese Earth Resources Satellite-I Synthetic Aperture Radar JERS-I SAR data can reveal subsidence conditions in the studied Makassar city area. Landsat TM （thematic mapper） images were used to evaluate the change of land cover during the observation period of 1994-1999. Makassar is fiat, covered mainly by alluvium deposit that is vulnerable to the load of constructions, and volcanic formations which is porous and will easily be degraded by groundwater extraction. It is found that mostly the subsidence has occurred in the western part of the city, including the industrial district, reclamation area, trading center area and the seaport area. The ground survey has indicated that high human activity exists in every point of subsidence. It is likely that various human activities such as ground water pumping and construction work should have affected the local subsidence phenomena in Makassar, as in the case of other large-scale cities in Indonesia.     

Shift catalysts in biomass generated synthesis gas

One of the CHRISGAS project objectives is to study the shift catalysts in biomass-generated synthesis gas. The water gas shift reaction is ruled by equilibrium, and the state of the gas can for a given H₂/CO ratio be shifted by addition/removal of water, CO₂ and/or by a change in the temperature. Stability area in respect to gas composition, sulphur content, pressure and temperature for FeCr shift catalyst has been investigated by thermodynamic equilibrium calculations. The calculations show that carbide formation is favourable in the “Normal water” case without sulphur in the gas. If sulphur is present in the gas, the situation improves due to sulphide formation.     

Pulsed eddy current testing with variable duty cycle on rivet joints

In pulsed eddy current testing, repetitive excitation signals with different duty cycles have different spectral representations. This work studies the influence of duty cycle on the ability to detect holes and EDM notches beneath rivet heads in subsurface layers of stratified samples. Feature patterns for the integrity of rivet joints are proposed and verified. The proposed method has the added advantage in that no reference sample is needed while employing multiple pulse measurements, with different pulse widths. Experimental testing and modelling approaches are discussed in connection with defect depth quantification, which can be extended to the quantification of complex defects.     

Morphology and property changes in PLA/PHBV blends as function of blend composition

PLA/PHBV blends were prepared by melt mixing. The morphology and physical properties of the blends and neat polymers were investigated. Scanning electron microscopy (SEM) studies provided evidence of interfacial cavities and weak interfacial interaction between the two polymers, and no obvious co-continuous morphology was observed in any of the investigated blends. Positron annihilation lifetime spectroscopy (PALS) indicated the presence of open-volume cavities with sub-nanometre diameters; far smaller than observed from the SEM images. The mean size and relative concentration of these cavities increased with increasing PHBV content. A weak negative deviation in the mean size for low PHBV content possibly indicates some degree of partial miscibility. The glass transition temperature of PLA in the blends decreased with increasing PHBV content, and offers support to some PHBV being miscible with the PLA. The degree of crystallinity in the blends show interesting behaviour that may be explained in terms of the complex morphology observed for these blends. The thermal conductivity of the samples varied with composition, but increased with increasing PHBV content, which was probably related to the increasing crystallinity. Both the tensile strength and Young’s modulus decreased with increasing PHBV content for the sequence of blends, and both parameters exhibited maximum values for 10 wt.% PHBV. For samples between 50/50 and 10/90 PLA/PHBV the tensile strength and Young’s modulus were comparable to or lower than those for both the neat polymers.