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The purpose of this study was to examine the effect of the magnetic field to the friction coefficient in the rolling element bearings which exists in electric motors.

To achieve this, the test rig was modified to adjust the density of the magnetic flux applied to the rolling ball element bearing. Experiments were carried out in the magnetic field from 0 to 7.5 mTesla at magnetic flux density range from 15, 40 and 65 N constant loads. Also, its rotary speed selected as 100, 200, 400, 800 to 1200 rpm, respectively.

In the majority of the experiments, it was observed that the magnetic field affected the friction coefficient. This influence reduced the friction coefficient in some experimental conditions and increased in some of them.

In the literature, there are very few studies on the effect of magnetic flux density to the friction coefficient in these rolling element bearings. It has become clear that more studies have been conducted on the effects of the magnetic field and/or electrical current on bearing damages and failures. This aspect is a study with specificity.

The purpose of this paper was to create conditions for the correct decision concerning an exchange of the used rope for a new one. A cognitive goal was to indicate the causes of its wear and determining its mechanism reliability and durability.

The magnetic, organoleptic and strength standard tests of lifting triangle-strand ropes of a mining hoist were carried out. This way the current state of the tested rope was defined.

On the basis of an analysis of the results of the performed tests: magnetic, organoleptic and fatigue tests, it can be said that the magnetic one is accurate enough only to indicate the place of the rope’s biggest weakening, though the degree of weakening is not defined precisely – with significant excess. The accurate rope’s destruction degree is indicated by the strength tests.

The results of described investigations can improve safety of the mining rope mechanisms operation, even for an increased resource.

The elementary wear processes, which are the basic reason for the destruction of the rope, are indicated. Rope destruction is caused mainly by tribological factors: abrasion, corrosion and fatigue wear. Magnetic tests are accurate enough only to indicate the place of the rope’s biggest weakening (qualitative index). Most precisely, the rope’s destruction degree (quantitative index) can be found by the strength tests.

This paper aims to develop of magnetic field controlled friction braking technology, a novel brake friction material with magnetic was designed and prepared in this paper.

The permalloy, a soft magnetic material, was selected as an additive to design and prepare the magnetic brake material. The friction, wear performance and permeability of each brake pads were investigated by experiments. By choosing the performance of friction coefficient fluctuation, friction coefficient deviation and mean wear rate as optimization parameters, the formulation of the magnetic friction material was optimized based on Fuzzy theory by using analytic hierarchy process methods and SPSS software.

The results showed that the developed soft magnetic friction material has not only superior friction coefficient, permeability and inferior wear rate but also good physical and mechanical properties.

Permalloy powder was added to the formulation of friction material to achieve a new functional friction material with high magnetic permeability. It is believed that this research will be of great theoretical and practical significance to develop both new brake materials and active control technology of the braking process in the future.

In rotational alternating current machines, interlocking is a commonly used manufacturing method to fix laminated silicon steel cores. The purpose of this study is to measure the localized magnetic properties more comprehensively and to analyze the deteriorated magnetic properties caused by interlocking more accurately.

A movable B–H sensor is designed in this paper. The localized magnetic properties measurement was performed to investigate the magnetic properties around the interlocks with various sizes, various orientations and various numbers of laminations. Then, the damaged area caused by the interlocking was quantified, and the magnetic degradation of different degrees is layered.

The measurement results have shown that the interlocks with larger sizes, along the transverse direction and on 10-layer laminate, will lead to more serious magnetic degradation, and the maximum loss increment can reach up to 70%.

This work is an improvement and optimization based on the previous overall magnetic measurement of the interlock. The quantitative results of the localized magnetic measurement will have a certain significance for the accurate modeling and simulation of the electrical machines and provide valuable guidance for the optimization of the actual production process of the motor.

This paper aims to present the design and fabrication of a rotary magnetostrictive energy generator, using to harvest the rotation energy of human knee joint.

A rotary magnetostrictive energy generator is presented in this paper. The harvester consists of six movable flat Terfenol-D rods, surround by the picked-up coils respective, and alternate permanent magnet (PM) array fixed in the upper cover of the stator. The harvester rotates like as a stepper motor, which has rotary electromagnetic power generating effect and impacted magnetostrictive power generating effect in its rotation. Modeling and simulation are used to validate the concept. A prototype of harvester is fabricated and subjected to the experimental characterization.

The size of proposed structure is control as 77 cm³, and its mass is about 0.21 kg. Huge induced voltage generated in the short-time impact situation, and that induced voltage in the harvester can up to 18.6 V at 0.32 s stepper rotation. Also, the presented harvester has good harvesting effects at low frequency human walking situation, which is suitable to be used for future researches of wearable knee joint applications.

A new concept of magnetostrictive harvester is presneted, which will be benefit for the application of human knee joint wearable. Also, this concept will give us more idea for collection of human movement energy.

Eddy current testing (ECT) is widely used in the non-destructive evaluation of materials in different industries. In this paper, ECT has been used to detect the presence of cracks in boiler tubes. The most important feature in ECT is the way in which the eddy currents are induced and detected in the sample. The authors have tried to design a new sensor that is effective in detecting cracks in boiler tubes. The purpose of this paper is to study the response of this sensor to cracks of different depths and dimensions.

The designed eddy current sensor is equipped with an exciting and a sensing coil. An alternating current is passed through the exciting coil thus producing eddy currents. The sensing coil scans the outer surface of the boiler tube and looks for abrupt changes in output signals resulting from sharp discontinuities in structure.

The sensor designed can detect the position of the crack. The presence of crack is indicated by a reduction in the induced voltage in the sensing coil. The sensor is also used for characterisation of the cracks, and can distinguish between cracks of varying shape, size and depth. The sensitivity of the sensing coil to cracks is dependent on operating conditions, such as frequency and voltage of the excitation signal.

The new sensor designed is used to detect defects in boiler tubes in power plants. However, the operating conditions, such as excitation frequency and amplitude will vary with composition of the boiler tubes.

The new eddy current sensor designed for crack detection is an E-shaped core coil. The shape of the coil provides a high permeability path to the magnetic field lines, thus reducing the loss of the field produced. This helps in improving the sensitivity of the coil, and makes the detection system effective in detecting hairline cracks.

The purpose of this paper is to propose an attitude determination and control scheme for a low‐cost Micro‐satellite with defective inertia. Restricted by the payload design, the z‐axis inertia of this satellite is larger than the x and y axes, which is unstable for natural attitude dynamics.

An original operation mode is designed to avoid z axis from long‐time pointing to the sun during damping, which avoids some unexpected damage. In attitude determination design, EKF and UKF algorithms are compared on estimation accuracy, convergence time and computation complexity in attitude estimation design, which is referred to determine the final estimation scheme. A DSP‐based hardware solution is achieved and a semi‐physical testing and simulation system is built.

Simulation results show the 3‐axis stable mode can be built with the proposed scheme, and the unprotected facet of the satellite can be kept away from long‐time pointing to the sun.

The proposed ADCS scheme can be a reference for the future Micro‐satellite programs which share the similar configuration.

Non‐destructive testing (NDT) makes use of the controlled application of physical phenomena to materials so that interpretation of signals derived from the materials indicates their fitness, or otherwise, to perform a design function. The purpose of NDT is to ensure that mainly load carrying components and structures are free from defects. Established non‐destructive testing has become of primary importance in aircraft maintenance and manufacture both as a positive indication for safety and as a method of saving costs. This article written for aircraft engineers is a broad review of the development of NDT in their industry and a brief indication of the status of its various components today.

Guidelines for making a wise choice when selecting high temperature alloys are provided. Four groups of alloys are discussed, along with helpful selection criteria. Substantial benefits accrue from contemporary alloy manufacturing techniques. Process databases and state‐of‐the‐art forging equipment significantly impact product quality, consistency and cost effectiveness. Finally, the author suggests that the elimination of unnecessary test requirements offers potential for savings in time and money. He feels that alloy integrity can be assured by any producer who can demonstrate narrow limits of compositional control, as well as melting, remelting and hot working controls.