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The purpose of this study is to investigate the application of non-destructive testing methods in measuring bearing oil film thickness to ensure that bearings are in a normal lubrication state. The oil film thickness is a crucial parameter reflecting the lubrication status of bearings, directly influencing the operational state of bearing transmission systems. However, it is challenging to accurately measure the oil film thickness under traditional disassembly conditions due to factors such as bearing structure and working conditions. Therefore, there is an urgent need for a nondestructive testing method to measure the oil film thickness and its status.

This paper introduces methods for optically, electrically and acoustically measuring the oil film thickness and status of bearings. It discusses the adaptability and measurement accuracy of different bearing oil film measurement methods and the impact of varying measurement conditions on accuracy. In addition, it compares the application scenarios of other techniques and the influence of the environment on detection results.

Ultrasonic measurement stands out due to its widespread adaptability, making it suitable for oil film thickness detection in various states and monitoring continuous changes in oil film thickness. Different methods can be selected depending on the measurement environment to compensate for measurement accuracy and enhance detection effectiveness.

This paper reviews the basic principles and latest applications of optical, electrical and acoustic measurement of oil film thickness and status. It analyzes applicable measurement methods for oil film under different conditions. It discusses the future trends of detection methods, providing possible solutions for bearing oil film thickness detection in complex engineering environments.

In this paper, it is shown that the so‐called in‐situ electrical measurement technique is a valuable tool for understanding failure mechanisms in thick film dielectrics. The technique makes it possible to measure important electrical characteristics of thick film dielectric systems in the temperature range from room temperature up to 900°C. This information is essential to understand failure mechanisms and to optimise the system with respect to quality and reliability. Mainly two electrical properties have been investigated: (i) the electrical resistance of the dielectric as a function of temperature and (ii) the spontaneous electromotive force occurring at higher temperatures between two metal layers with the dielectric in between. A significant result of the work is the observation of a close correlation between the leakage current measured through the dielectric at elevated temperatures, and the ability of the dielectric to resist shorting and blistering effects during the preparation of circuits. Secondly, from in‐situ voltage measurements, it was confirmed that the mixed metallurgy system Au(bottom)‐dielectric‐Ag(top) acts at 850°C as a spontaneous battery, and the battery voltage (i.e., the spontaneous electromotive force) was measured. Depending on the type of dielectric, a battery voltage up to 200 mV between the two metal layers was observed. As a result of this spontaneous electromotive force, blistering occurs. The battery voltage was shown to be much smaller in unmixed metallurgy systems with Ag(bottom)‐dielectric‐Ag(top) or Au(bottom)‐dielectric‐Au(top). However, if an external voltage of 300 mV is applied to such a system during a temperature profile up to 850°C, blisters can also be induced. This shows unambiguously that blistering is a voltage driven effect.

The electric potential techniques are of two types: the direct current potential drop method (DCPD) and the alternating current potential drop method (ACPD). While the latter can be used mainly to detect surface defects, the first is more appropriate for detecting the initiation of cracks and monitoring their growth. One of the advantages of the ACPD is that it can be easily employed as a non‐destructive inspection tool. The DCPD has been used mainly in the laboratory environments under various conditions of loading including high gross inelastic deformations where subsurface flaws are present. Both these techniques have high accuracy and can be used as tools to detect defects in manufactured parts such as flaws in welds. Their findings are very useful in preventive maintenance; the inspectors and engineers use them to take decisions for scheduling maintenance. The present paper presents a review of the evolution in the design of ACPD and DCPD systems, with their advantages, disadvantages and fields of application. It is shown that ACPD and DCPD have comparable sensitivity and are widely used for surface crack measurement. The relatively new AC field measurement technique will be described. Its performance will be compared to that of ACPD. The use of DCPD in applications involving high temperature and gross inelastic strains will be stressed. The results obtained in low cycle fatigue conditions show that by including a special reference potential ratio, the DCPD yields a good estimation of the average surface and subsurface crack lengths. The method also allows an accurate detection of crack initiation in these conditions.

Electronic packaging is increasingly becoming a vital part of the electronics industry, representing a key barrier to cost reduction and performance improvement. Of all the packaging methods, flip‐chip technology offers, up to now, the highest packaging density and best electrical performance. In this paper, flip‐chip test design considerations, process development and driving forces for adhesive joining and soldering flip‐chip processes will be given. Reliability test results of flip‐chip interconnection technology using conductive adhesive joining will also be presented. The electrical contact nature of the adhesive joint will be elaborated in the light of continuous and static electrical resistance measurement. Future research work directions in flip‐chip joining using eutectic solder and conductive adhesives on flexible circuits will also be discussed.

The purpose of this paper is to verify the influence of superplasticizer and air entrainment admixtures (AEs) in the electrical resistivity of concrete.

Ten different types of concrete have been studied. Three levels of superplasticizer and air AEs have been used (0.20, 0.35 and 0.50 per cent). Concrete samples were cast and the electrical resistivity was monitored at the ages of 28, 63 and 91 days. Compressive strength and density tests have also been executed.

The superplasticizer admixture presented an optimal level of 0.35 per cent that significantly increased the electrical resistivity. The air AEs at the same dosage caused a considerable decrease in the electrical resistivity. The concrete with air AEs showed highest resistivity/MPa ratio.

The results should be carefully extrapolated for other materials and admixtures.

The usage of chemicals admixture in concrete is extremely common nowadays. However, only a few authors have studied the impact of such materials on the concrete’s electrical resistivity. Since many other researchers have already correlated electrical resistivity with other concrete’s properties, such as strength, setting time and corrosion probability, it is important to better understand how superplasticizers and air-entraining agents, for instance, impact the resistivity.

The vast majority of studies only tested the resistivity of cement paste or mortar and usually for short period of time (up to 28 days), which seems not to be adequate since the cement reaction continues after that period. This paper fills this gap and studied the impact of admixture on concrete and for a period of 91 days.

The purpose of this paper is to provide a comprehensive review of a non-contact full-field optical measurement technique known as digital image correlation (DIC).

The approach of this review paper is to introduce the research pertaining to DIC. It comprehensively covers crucial facets including its principles, historical development, core challenges, current research status and practical applications. Additionally, it delves into unresolved issues and outlines future research objectives.

The findings of this review encompass essential aspects of DIC, including core issues like the subpixel registration algorithm, camera calibration, measurement of surface deformation in 3D complex structures and applications in ultra-high-temperature settings. Additionally, the review presents the prevailing strategies for addressing these challenges, the most recent advancements in DIC applications across quasi-static, dynamic, ultra-high-temperature, large-scale and micro-scale engineering domains, along with key directions for future research endeavors.

This review holds a substantial value as it furnishes a comprehensive and in-depth introduction to DIC, while also spotlighting its prospective applications.

The purpose of this paper is to share valuable information about metallization in microelectronic industries by implementing tungsten silicide (WSi) thin film materials.

Direct current plasma magnetron sputtering technique was employed for the WSi film growth. Different sputtering parameters were investigated, and the WSi films were characterized using four‐point probe electrical measurement method.

The experimental results reveal that the sputtering parameters such as deposition pressure and substrate temperature exert significant influence on the electrical properties of the WSi films.

By tuning the sputtering parameters, the electrical properties of the WSi films can be optimized and the film resistivity can be reduced significantly.

The investigation results presented in this paper are useful information for microelectronic industries in the area of microelectronic devices metallization.

The fabrication method described in this paper allows fabricating low‐resistivity WSi films by employing a lower deposition pressure and a lower substrate temperature.

Corrosion is an electrolytic phenomenon. The corroding metal is at higher potential than its surroundings. Accordingly, there will be a flow of electricity away from the metal, leaving the metal in an ionised (oxidised) state. Chemical combination with oxygen from the surroundings must occur simultaneously for electrical balance.

This paper aims to present the results of measurements and calculations illustrating mutual thermal coupling between power Schottky diodes made of silicon carbide situated in the common case.

The idea of measurements of mutual transient thermal impedances of the investigated device is described.

The results of measurements of mutual transient thermal impedances between the considered diodes are shown. The experimentally verified results of calculations of the internal temperature waveforms of the considered diodes obtained with mutual thermal coupling taken into account are presented and discussed. The influence of mutual thermal coupling and a self-heating phenomenon on the internal temperature of the considered diodes is pointed out.

The presented methods of measurements and calculations can be used for constructing the investigated diodes made of other semiconductor materials.

The presented results prove that mutual thermal coupling between diodes mounted in the common case must be taken into account to calculate correctly the waveforms of the device internal temperature.

The corrosive power of solder pastes is studied by implementing a new method compatible with the common rules of use. The entire methodology is fully described. The results show evidence of corrosion with some solder pastes that have been identified by microscopic and EDX analysis. The corrosion mechanism is ‘mouse bite’ and conductive anodic filaments. A ranking of the different solder pastes tested is given and pass criteria for this new method of evaluation are proposed.