Study of gamma radiation shielding on tellurite glass containing TiO2 and Al2O3 nanoparticles.

Radiation shielding incorporates material between the radioactive source and environment to decrease exposure to hazardous radiation. It remains to be seen whether the addition of nanoparticles effectively increases the protection of tellurite glass system from further degradation under irradiation conditions. This study revealed the gamma radiation effects on tellurite glass. The tellurite glass samples were irradiated with 50 kGy and 100 kGy gamma ray, and subsequently analysed using X-ray diffractometer (XRD), atomic force microscopy (AFM), and ultraviolet-visible spectroscopy (UV-Vis). Gamma radiation increased the creation of non-bridging oxygen (NBO) and caused colour change on TZNETi and TZNETiAl glasses. Consequently, the addition of aluminium oxides (Al2O3) was found to lower the density of glass systems. The glass samples surface roughness increased, while the optical transmission spectra decreased after 50 kGy of gamma ray irradiation. Nevertheless, the glass system maintained its transparency even after irradiation. The mass attenuation coefficient (MAC) values represented the shielding effectiveness demonstrated by the investigated glass with the addition of Al2O3. The physical, structural, optical, and radiation shielding properties showed that 69.1TeO2-20ZnO-9Na2O-1Er2O3-0.3TiO2-0.6Al2O3 (TZNETiAl) sample exhibited strong shielding properties amongst the fabricated tellurite samples.

Inspecting Histamine Isolated from Fish through a Highly Selective Molecularly Imprinted Electrochemical Sensor Approach.

Numerous analytical approaches have been developed to determine histamine levels in food samples due to its health consequences. Consuming histamine over the Food and Drug Administration (FDA)-regulated 50 mg kg-1 limit would result in chronic toxicity. Consequently, the present study discusses a novel electrochemical approach to evaluate histamine levels in fish products via a molecularly imprinted polymer (MIP) on an electrode surface. The film was produced with electropolymerized polyurethane (PU), which maintained the histamine compound. Fourier-transform infrared (FTIR) spectroscopy was applied to verify the MIP manufactured in this study. The capability of the polymer was measured by assessing its electron shifts with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was also employed to validate the sensing method. The MIP/screen-printed electrode (SPE) and non-imprinted polymer (NIP)/SPE recorded a linear response ranging from 1 to 1000 nmol L-1 at the 1.765 and 709 nmol L-1 detection limits. The sensing technique was subsequently utilized to determine the histamine levels in selected samples at room temperature (25 °C). Generally, the sensor allowed the accurate and precise detection of histamine in the fish samples. Furthermore, the approach could be categorized as a simple technique that is low-cost and suitable for on-site detections.

Polyurethane Application to Transform Screen-Printed Electrode for Rapid Identification of Histamine Isolated from Fish.

The toxicity of histamine has attracted numerous researchers to develop a method for histamine determination purposes. The Food and Drug Administration (FDA) unequivocally prohibits the consumption of histamine above 50 mg·kg-1. Thus, an innovation in histamine detection in fish has been developed in this research. The investigation of the histamine level in fish has been conducted by using an electrochemical sensor approach and producing a polymer via molecularly imprinted polymer (MIP) on a screen-printed electrode. The technique was validated by assessing the shifts in electron shifting using the cyclic voltammetry (CV) approach and electrochemical impedance spectroscopy (EIS), whereas differential pulse voltammetry (DPV) was applied to validate the sensor method. The instruments showed a linear response ranging from 1-1000 nmol·L-1, with a detection limit of MIP/SPE at 1.765 nmol·L-1 and 709 nmol·L-1 for the NIP/SPE, respectively. The sensing technique was employed to determine the histamine level in selected samples at room temperature (25°C). The outcomes of this study indicated that the validated chemical sensor allowed accurate and precise detection of fish samples and can be categorized as a simple approach. The instrument is inexpensive and suitable for on-site detection.

A guide to designing graphene-philic surfactants.

HYPOTHESIS: As compared to common aliphatic surfactants, increasing the number of pendant or incorporated aromatic groups in a surfactant is expected to offer significant enhancement in the affinity for graphene surfaces. The basis for enhanced graphene-philicity of aromatic surfactants is that they can develop appreciable π - π interactions with graphene. Furthermore, charged (anionic) surfactants are expected to confer electrostatic stabilization on surfactant-graphene composites. Hence, it is expected that anionic aromatic surfactants combine these two properties for effective stabilization of graphene dispersions in water. EXPERIMENTAL: The properties of two custom made graphene-compatible surfactants carrying two and three aromatic moieties in the hydrophobic tails, namely DC3Ph2 (sodium 1,4-dioxo-1,4-bis(3-phenylpropoxy)butane-2-sulfonate) and TC3Ph3 (sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate) were compared with other common ionic commercial surfactants. Air-water (a/w) surface tension measurements were used to assess the surfactant adsorption and interfacial packing in the absence and presence of graphene. The surfactant coverage index for graphene (Ф) was calculated using surfactant headgroup areas derived from a/w surface tension data, chain volumes, and molecular fragment volumes from literature. FINDINGS: Increasing the number of aromatic groups and tails per surfactant was shown to increase the ability of surfactants to pack and fill space, as expressed by Ф. Comparison between the values of Ф for surfactants of different chain structure and architecture showed that the affinity for graphene increased with Ф. Hence, there is an implicit link between surfactant-graphene compatibility and the identity, chemical composition and architecture of the surfactant chains.

An Experimental Investigation of Static Properties of Bio-Oils and SAE40 Oil in Journal Bearing Applications.

Considerable research has been conducted in the past decade and a half regarding the bio-lubricants potential to replace mineral-based lubricants as mainstream lubricants such as engine oil, hydraulic oil, compressor oil, and metalworking oil. This study studied several bio-lubricants (rapeseed oil, palm olein, and soybean oil) and a mineral-based lubricant, SAE40. The bio-lubricants have better physiochemical, tribological characteristics and environmental friendly nature, and are promising to replace mineral-based lubricants. In this study, a journal bearing test rig (JBTR) was developed in order to investigate the effect of journal speed on the temperature of oil film with time. Additionally, the load-carrying capacity of bio-oils was tested against the mineral-based lubricant SAE40 by adding a load on the journal. For all three speeds, i.e., 1000, 1500, and 2000 rpm, the bio-lubricants recorded minimum temperature. At 1000 rpm, rapeseed oil recorded a 9.2% lower temperature than SAE40. Similarly, at 2000 rpm, rapeseed oil recorded a minimum temperature that was 2.5% lower than SAE40; in comparison, at 1500 rpm, palm olein recorded a minimum temperature that was 1.8% less than SAE40. Overall, the results of this study revealed that bio-oils recorded a lower temperature rise than mineral oil. These results are very encouraging for further research in this area.

Enhanced dispersion of multiwall carbon nanotubes in natural rubber latex nanocomposites by surfactants bearing phenyl groups.

Here is presented a systematic study of the dispersibility of multiwall carbon nanotubes (MWCNTs) in natural rubber latex (NR-latex) assisted by a series of single-, double-, and triple-sulfosuccinate anionic surfactants containing phenyl ring moieties. Optical polarising microscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy have been performed to obtain the dispersion-level profiles of the MWCNTs in the nanocomposites. Interestingly, a triple-chain, phenyl-containing surfactant, namely sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate (TCPh), has a greater capacity the stabilisation of MWCNTs than a commercially available single-chain sodium dodecylbenzenesulfonate (SDBS) surfactant. TCPh provides significant enhancements in the electrical conductivity of nanocomposites, up to ∼10(-2) S cm(-1), as measured by a four-point probe instrument. These results have allowed compilation of a road map for the design of surfactant architectures capable of providing the homogeneous dispersion of MWCNTs required for the next generation of polymer-carbon-nanotube materials, specifically those used in aerospace technology.