Experimental and finite element analysis of residual stress and distortion in GTA welding of modified 9Cr-1Mo steel

Journal of Mechanical Science and Technology - In this paper, investigation of residual stress and distortion induced in 3 mm thick Modified 9Cr-1Mo steel plates during GTA welding is carried out....     

Controlling magnetoelectric coupling by nanoscale phase transformation in strain engineered bismuth ferrite

The magnetoelectric coupling in multiferroic materials is promising for a wide range of applications, yet manipulating magnetic ordering by electric field proves elusive to obtain and difficult to control. In this paper, we explore the prospect of controlling magnetic ordering in misfit strained bismuth ferrite (BiFeO(3), BFO) films, combining theoretical analysis, numerical simulations, and experimental characterizations. Electric field induced transformation from a tetragonal phase to a distorted rhombohedral one in strain engineered BFO films has been identified by thermodynamic analysis, and realized by scanning probe microscopy (SPM) experiment. By breaking the rotational symmetry of a tip-induced electric field as suggested by phase field simulation, the morphology of distorted rhombohedral variants has been delicately controlled and regulated. Such capabilities enable nanoscale control of magnetoelectric coupling in strain engineered BFO films that is difficult to achieve otherwise, as demonstrated by phase field simulations.     

Synthesis of chloroanilines at a Ti/ceramic TiO2-cathode

Electroreduction of 2-, 3- and 4-chloronitrobenzenes (2-CNB, 3-CNB and 4-CNB) to the corresponding chloroanilines has been carried out under galvanostatic conditions in aqueous H₂SO₄ at a Ti/ceramic TiO₂-cathode. A comparison of the yield and current efficiency (CE) for the amine formation at a Ti/ceramic TiO₂-cathode with that at a copper cathode indicates the electrocatalytic nature of the former electrode. The results on the cyclic voltammetric behaviour of 2-CNB, 3-CNB and 4-CNB at a Ti/ceramic TiO₂-cathode are also reported, and indicate a mechanism involving heterogeneous redox catalysis by Ti⁴⁺/Ti³⁺.     

Low-Temperature Sintering and Microwave Dielectric Properties of Li2MgSiO4 Ceramics

Development of a low-temperature sintered dielectric material derived from Li₂MgSiO₄ (LMS) for low-temperature cofired ceramic (LTCC) application is discussed in this paper. The LMS ceramics were prepared by the solid-state ceramic route. The calcination and sintering temperatures of LMS were optimized at 850°C/4 h and 1250°C/2 h, respectively, for the best density and dielectric properties. The crystal structure and microstructure of the ceramic were studied by the X-ray diffraction and scanning electron microscopic methods. The microwave dielectric properties of the ceramic were measured by the cavity perturbation method. The LMS sintered at 1250°C/2 h had ɛ_r=5.1 and tan δ=5.2 × 10⁻⁴ at 8 GHz. The sintering temperature of LMS is lowered from 1250°C/2 h to 850°C/2 h by the addition of both lithium borosilicate (LBS) and lithium magnesium zinc borosilicate (LMZBS) glasses. LMS mixed with 1 wt% LBS sintered at 925°C/2 h had ɛ_r=5.5 and tan δ=7 × 10⁻⁵ at 8 GHz. Two weight percent LMZBS mixed with LMS sintered at 875°C/2 h had ɛ_r=5.9 and tan δ=6.7 × 10⁻⁵ at 8 GHz.     

Synthesis and physico-chemical evaluation of water-soluble epoxy ester primer coating

The objective of this paper was to formulate high performance water-based paints by an esterified epoxy resin, synthesized by reacting epoxy resin with pyromellitic dianhydride (PMDA) and pigmented with non-toxic phosphate using varying pigment-volume concentrations (PVCs). The influence of pigment concentrations on some physico-chemical properties was evaluated and assessed for the optimized PVC coating formulation. The structural and thermal stability of the epoxy ester vehicle was also evaluated through FT-IR and thermogravimetric analysis (TGA). Film properties of the coatings were studied and it was found that the coating composition at lower PVCs exhibited better film property over higher PVCs.     

The effect of lubricant additives on friction and wear studies of polyphenylene sulphide

Polyphenylene sulphide is a polymer with good thermal stability and high crystallinity. This paper summarizes the results of friction and wear studies of polyphenylene sulphide and its composites made with conventional solid lubricants to ascertain the suitability of the material as a matrix for solid lubricant additives. The polymer itself has a high coefficient of friction. Wear rate increases with load and speed. Addition of solid lubricant additives helps in improving the friction and wear of the polymer. Composites with MoS₂-Sb₂O₃ and PTFE gave better results than composites made by the addition of graphite and MoS₂ graphite. Wear rate of these composites increased with load and speed; but load and speed had little effect on friction.