In situ synthesised TiO2 ‐chitosan‐chondroitin 4–sulphate nanocomposites for bone implant applications

The artificial materials for bone implant applications are gaining more importance in the recent years. The series titania‐chitosan‐chondroitin 4–sulphate nanocomposites of three different concentrations (2:1:x, where x ‐ 0.125, 0.25, 0.5) have been synthesised by in situ sol–gel method and characterised by various techniques. The particle size of the nanocomposites ranges from 30–50 nm. The bioactivity, swelling nature, and the antimicrobial nature of the nanocomposites were investigated. The swelling ability and bioactivity of the composites is significantly greater and they possess high zone of inhibition against the microorganisms such as Staphylococcus aureus and Escherichia coli. The cell viability of the nanocomposites were evaluated by using MG‐63 and observed the composites possess high cell viability at low concentration. The excellent bioactivity and biocompatibility makes these nanocomposites a promising biomaterial for bone implant applications.Inspec keywords: titanium compounds, filled polymers, nanocomposites, bone, orthopaedics, biomedical materials, sol‐gel processing, nanofabrication, particle size, swelling, microorganisms, cellular biophysics, nanomedicine, prostheticsOther keywords: in situ synthesised TiO₂ ‐chitosan‐chondroitin 4‐sulphate nanocomposites, bone implant applications, artificial materials, in situ sol‐gel method, particle size, swelling nature, antimicrobial nature, microorganisms, Staphylococcus aureus, Escherichia coli, cell viability, MG‐63, biomaterial, size 30 nm to 50 nm, TiO₂      

Process Parameter Optimization in Jatropha Methyl Ester Yield Using Taguchi Technique

Among all alternate fuel sources available, the biodiesel of Jatropha curcas appears to be a potential fuel as it widely exists in Asia. The Jatropha methyl ester (JME) is produced by transesterification process. In the transesterification process, alkyl group of ester exchanges with that of an alcohol. This work focuses on optimizing various parameters like quantities of methanol, KOH, and stirrer speed, which influence high JME yield. Based on L₉ orthogonal array, experiments are conducted by using Taguchi technique. All the nine combinations of L₉ orthogonal array are experimentally done for extraction of JME, and then it is used for analysis in Taguchi technique. The analysis of maximum yield is done on the basis of “larger is better” signal to noise ratio (S/N ratio). The best combination in the L₉ orthogonal array is found to be methanol (110 ml), KOH (1.306 gm), and stirrer speed (1200 rpm). The influence of methanol, KOH, and stirrer speed on the yield is found by analysis of variance (ANOVA). Based on the results of ANOVA, it is found that the influence of methanol, KOH, and stirrer speed on the yield are obtained as 70.10%, 20.35%, and 5.78%, respectively.     

A future for timber-concrete composites?

In countries where timber is readily available, can it be used to advantage with concrete as a composite structural unit? Research, still in its early stages at the Department of Building Science, University of Singapore, suggests that shallow composite beams of this kind have considerably enhanced strength.     

Crystal slip modeling of small strain yield behavior in textured copper tubing

A self-consistent polycrystalline model developed by Kr?ner, and Budiansky and Wu (KBW) was used to model small strain (2 and 8 × 10_-6) biaxial yield behavior in textured copper tubing. The results were compared to simulations using the Bishop-Hill model and a lower bound (LB) model which neglected strain compatibility. It was found that the Bishop-Hill model poorly represents texture effects whereas the KBW and LB models give accurate predictions of biaxial yield surfaces at these strain levels. A linear latent hardening law was used with both the KBW and LB model. Varying the latent hardening ratio an order of magnitude had little effect on the yield surface. Introducing the odd 1 coefficients of the generalized spherical harmonic expansion was also found to have negligible effect on the predicted yield loci. Formerly Graduate Student of Mechanical Engineering at Brigham Young University Formerly Graduate Student of Materials Science and Engineering at the University of Florida     

A survey on future research about electron beam welding for aerospace applications

Electron beam welding plays an important role in the aerospace industry where components like sensors,gears,actuators and air frames used in aircraft and rocket engines were welded using this technique.Welding is normally performed in a vacuum to avoid the scatter of electron due to the presence of gas molecules in the atmosphere and hence electron beam welding process provides the greater results.But still joining of dissimilar metals is challenging.This paper represents review of process,generation and distribution of heat source various input parameters,materials,microstructure,mechanical strength and the possibilities of joining dissimilar metals using electron beam welding.     

Effect of different plasticizer on structural and electrical properties of PEMA-based polymer electrolytes

Plasticized poly(vinyl chloride)/poly(ethyl methacrylate) PVC/PEMA-based blend polymer electrolyte films containing lithium perchlorate (LiClO₄) as a salt were prepared by solvent casting technique. The effects of the plasticization on structural, thermal and electrical properties of the plasticized polymer blend electrolytes were investigated. The changes in the structural and complex formation properties of the materials were studied by XRD and FTIR techniques. Dielectric relaxation studies of the polymer electrolyte have been undertaken, and the results are discussed. TG/DTA technique is used to study the thermal stability. Complex impedance analysis is used to calculate the bulk resistance of the complexes. The effect of different plasticizer on the structural and physical properties of polymer blend electrolyte is well correlated.     

Hydrogen Generation from CO2 Reforming of Biomass-Derived Methanol on Ni/SiO2 Catalyst

Topics in Catalysis - CO2 reforming of methanol for producing hydrogen was experimentally carried out in a fixed-bed reactor on 10%Ni/SiO2. The 10%Ni/SiO2 was completely reduced during H2...     

Analytical solution of amperometric enzymatic reactions based on Homotopy perturbation method

Electrochemical polymerization is a simple and direct technique often employed for immobilizing redox enzymes at an electrode surface. Besides these, it allows precise control over the amount, spatial distribution and orientation of the enzymes. Analytical expressions pertaining to the immobilization of enzyme by electrochemical polymerization on the electrode surface were obtained by Homotopy perturbation method (HPM). This expression further distinguishes the product of the enzyme reaction at the electrode surface from those occurring alongside the polymer employed for immobilization. These analytical results are compared with the available limiting case results and they are found to be in good agreement.     

Novel Li-ion conduction on poly(vinyl acetate)-based hybrid polymer electrolytes with double plasticizers

Polymer blend electrolytes comprising of poly(vinyl acetate), poly(vinylidene fluoride-co-hexafluoropropylene), LiClO₄, and EC-based plasticizer combinations (EC + PC, EC + GBL, EC + DMP, EC + DBP, EC + DEC) are prepared by solvent casting technique. Ionic conductivities of the electrolytes are determined by ac impedance studies in the temperature range 303–363 K. Among the various combinations of plasticizers, EC + PC added complex exhibits maximum ionic conductivity of the order of 10⁻⁴ S cm⁻¹ and the temperature-dependent ionic conductivity plots seem to obey the VTF relation. The structural and complex formations of the prepared samples have been confirmed by X-ray diffraction analysis. DSC technique is used to study the thermal behaviour. The surface images of the sample having maximum ionic conductivity are analyzed with the help of SEM and AFM techniques.