Fabrication and optimization of polypyrrole/cerium oxide/glassy carbon sensing platform for the electrochemical detection of flupirtine

Journal of Applied Electrochemistry - In spite of single nanomaterials, nanocomposites have come to be the superior modifying materials for electrochemical sensing. Herein, the highly...     

Exploration of highly correlated Co‐based quaternary Heusler alloys for spintronics and thermoelectric applications

The half‐metallic character of new quaternary Heusler alloys CoXMnAs (X = Ru, Rh) is established along with their thermoelectric, mechanical, and thermodynamic properties. The optimization of energy suggests that alloys are stable in Y2‐type structure with a ferromagnetic character. The electronic band profile through generalized gradient approximation and modified Becke‐Johnson potential indicates the metallic character of alloys. However, with inclusion of Hubbard potential to generalized gradient approximation, the alloys depict half‐metallic character with semiconducting nature in spin‐down state. The alloys possess high magnetic moment, CoRuMnAs has 5 μB, whereas CoRhMnAs has 6 μB, following Slater‐Pauling rule M_T = Z_T ? 24. The narrow band gap in spin‐down channel enhances the thermoelectric properties. The maximum value for thermopower (|S|) obtained is 44.3 and 53.44 μV/K for CoRuMnAs and CoRhMnAs, respectively. The variation of electrical conductivity, Seebeck coefficient, and figure of merit affirm increasing trend with temperature, which is a good indication of materials to be used in thermoelectric technology. The mechanical stability along with ductile nature of alloys is determined through elastic constants. Further, we have calculated thermodynamic properties and have established their dependence on temperature and pressure using quasi‐harmonic Debye model. The half‐metallic nature with efficient thermoelectric parameters strongly supports the possible application of alloys for spin devices and green energy generation.     

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...     

Modification of glass ionomer cement by incorporating hydroxyapatite-silica nano-powder composite: Sol–gel synthesis and characterization

A nanohydroxyapatite–silica powder was synthesized using an ethanol based sol–gel technique. The synthesized powder was incorporated into commercial glass ionomer powder (Fuji II GC) and characterized using FTIR, ²⁹Si CP/MAS NMR, EDX and XRD spectroscopy. ²⁹Si CP/MAS NMR results showed the presence of higher degree of cross-linking of silyl species between silica and GIC, which makes the Nano-HA–Silica–GIC composite much stronger. High-resolution transmission electron microscopy (TEM) and scanning electron microscopy (TEM) was employed to investigate the morphology of the synthesized powder. Results revealed that higher content of nanosilica produced a denser and stronger GIC. Thus, the application of nanohydroxyapatite–silica–GIC with improved properties are envisioned to be of great clinical importance, especially in stress bearing areas.     

Study of strengthening solutions for glued-laminated wood beams of maritime pine wood

The application of the concept of glued-laminated wood (glulam) to improve the mechanical properties of the solid wood of the maritime pine (Pinus pinaster) is the subject of this work. Two reinforced glued-laminated wood beams are proposed and assessed. The first is based on a concept of laminated wood composite with fiber glass; the second is based on the application of pultruded lamellas glued to the most stressed tensile region of the glued-laminated beams. In order to demonstrate the potential of the proposed strengthening solutions, a comparison between their mechanical behaviors and the mechanical behaviors of the conventional glued-laminated and solid beams are performed. Static load–deflection curves, an equivalent Young’s modulus, the ultimate strain and modulus of rupture are determined using 3-point quasi-static bending tests. In general, it is demonstrated the beneficial effect of the proposed strengthening solutions both in terms of resistance and ductility.     

An ANFIS-based approach for predicting the bed load for moderately sized rivers

A total of 346 sets of bed-load data obtained from the Kinta River, Pari River, Kerayong River and Langat River were analyzed using four common bed-load equations. These assessments, based on the median sediment size (d₅₀), show that the existing equations were unable to predict the measured bed load accurately. All existing equations over-predicted the measured values, and none of the existing bed-load equations gave satisfactory performance when tested on local river data. Therefore, the present study applies a new soft computing technique, i.e. an adaptive neuro-fuzzy inference system (ANFIS), to better predict measured bed-load data. Validation of the developed network (ANFIS) was performed using a new set of bed-load data collected at Kulim River. The results show that the recommended network can more accurately predict the measured bed-load data when compared to an equation based on a regression method.     

Graft Copolymerization of Acrylamide onto Oil Palm Empty Fruit Bunch (OPEFB) Fiber

Grafting of acrylamide (AAm) onto oil palm empty fruits bunch fiber using hydrogen peroxide as initiator and methyl acrylate as comonomer was investigated. The amount of comonomer needed to make grafting of acrylamide possible was determined. The percentage of poly(acrylamide) and the comonomer in the final graft copolymer was estimated by elemental analysis. Results obtained indicated that methyl acrylate facilitated the incorporation of acrylamide monomer onto OPEFB. The reactivity ratios for both monomers were determined by using Fineman–Ross plot. The effects of reaction temperature and period as well as amount of the initiator, solvent, monomer and comonomer on the percentage of grafting at fixed amount of comonomer (11 mmol) were studied. Maximum percentage of grafting was achieved when the amount of initiator and solvent 3.98×10⁻³ mol and 50 mL respectively. The optimum reaction temperature was 50 ^○C and the reaction period was 90 min. Highest percentage of grafting was 232% when 25.6 mmol of acrylamide was used under these optimum conditions. The presence of functional group in the grafted polymer is characterized by infrared spectroscopy and the surface morphology is observed by scanning electron microscopy. Thermoanalytic investigation on OPEFB and OPEFB-g-PAAM were carried out to evaluate the thermal stability and respective activation energy of the materials.     

Development of GEP-based functional relationship for sediment transport in tropical rivers

This study presents gene expression programming (GEP), which is an extension to genetic programming (GP), as an alternative approach to modeling the functional relationships for the River Kurau, River Langat, and River Muda of the Malaysia. A functional relation has been developed using GEP with non-dimensional variables. The development of a GEP non-dimensional model is described. This paper compares current prediction equation with the existing GEP model for the same rivers (Zakaria et al. in Sci Total Environ 408:5078–5085, (2010). The presented model in this study is a less input GEP model and that predicts good performance. The proposed GEP approach gives satisfactory results compared to existing predictors.