Development of a MIAB welding module and experimental analysis of rotational behavior of arc—simulation of electromagnetic force distribution during MIAB welding of steel pipes using finite element analysis

Magnetically impelled arc butt (MIAB) welding is a unique forge welding process in which an arc is drawn in the gap between the two tubes to be welded in order to raise them to a high temperature to allow forging to form a solid-state weld. In this case, the arc is rotated with a high speed around the weld line by an electromagnetic force resulting from the interaction of the magnetic field and the arc current. This paper presents the details of the results and the conclusions of the experimental trials conducted on the MIAB module designed and developed based on the principle. Further, nonlinear electromagnetic analysis has been performed to determine the magnetic field and electromagnetic force distribution in MIAB process using finite element package ANSYS. Typical results of this analysis pertaining to magnetic field are compared with the experimental data for steel tubes (outer diameter 47 mm and thickness of 2 mm). It is observed that the results from finite element analysis and the experimental trials are in excellent agreement. The proposed three-dimensional finite element method model for electromagnetic force distribution facilitates comprehensive understanding of the arc rotation process in MIAB welding.     

Construction of a standard force machine for the range of 100 μN–200 mN

A new force standard machine (FSM) for the range of 100 μN–100 mN has been developed [1]. The machine is based on the comparison of a force transducer with the indication of an electromagnetic compensated balance (ECB). Construction details as well as first measurements will be presented. To guarantee traceability to the established deadweight force machines, the new facility was compared with the PTB 200 N FSM.     

Dielectric and FTIR studies on blending of [xPMMA–(1 − x)PVC] with LiTFSI

Poly(methyl methacrylate) (PMMA)/poly(vinyl chloride) (PVC) polymer blend electrolytes with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) as a dopant salt were prepared by solution casting technique. Various blend ratio of PMMA/PVC was studied in this present work. Based on the results obtained from AC-impedance spectra, the weight ratio of PMMA/PVC that is 70:30 exhibited the highest ionic conductivity at room temperature. The ionic conductivity and dielectric relaxation studies of the blended polymer electrolyte have been determined by AC-impedance spectroscopy over a wide frequency regime. In addition, Fourier Transform Infrared (FTIR) studies revealed the complexation between PMMA, PVC and LiTFSI.     

Analysis of composition dependence of some thermal transport properties in glassy Se80−xTe20Snx (0 ⩽ x ⩽ 10) alloys using transient plane source measurements

In the present work, we have studied simultaneous measurements of thermal transport properties (effective thermal conductivity, diffusivity, specific heat per unit volume, thermal inertia I_T) of glassy Se_80−xTe₂₀Sn_x (0 ? x ? 10) system using their twin pellets. The glassy system is prepared under a load of 5 tons and measurements have been made at room temperature using Transient Plane Source (TPS) technique. The composition dependence of the thermal transport properties of given glassy system is also discussed.     

The parameters measurement of air–water two phase flow using the electrical resistance tomography (ERT) technique in a bubble column

The air–water two-phase flow is investigated in a bubble column with a height of 2 m and a diameter of 0.282 m by using the Electrical Resistance Tomography (ERT) technique. The flow characterization are measured by applying ERT sensors of three vertical sections with superficial gas velocities in the range 0.027–0.156 m/s. Based on the cross-correlation technique and dynamic gas disengagement (DGD) theory, the bubble Saunter diameters are obtained and the local axial velocity about two phases flow can be calculated. The results show that with increased gas superficial velocity the distribution of bubble size is gradually widespread. Moreover, the local velocity of gas bubble swarm has a center peak distribution with increased gas superficial velocity.