Condition Of Contacts Research Articles

Прогнозирование состояния плоскостных контактных соединений шин с применением моделей машинного обучения

The article considers the problem of predicting the technical condition of planar contact connections of tires in electrical installations. Modeling methods, including polynomial regression and autoregression, have been studied to assess and predict the state of contacts. The analysis of the results of the models was carried out and their effectiveness was evaluated on various data sets. A program for predicting the condition of contacts has been developed and integrated into the software for monitoring tire contacts. The results of the work show the prospects of creating monitoring systems using forecasting models to ensure the reliability and efficiency of electrical equipment. Keywords: MONITORING, CONTROL, TECHNICAL CONDITION, ELECTRICAL INSTALLATION, CONTACT CONNECTIONS

Thermal imaging control of electrical equipment of industrial enterprises

RELEVANCE. Thermal imaging control is used to monitor the technical condition of electrical equipment, as well as contacts and contact connections of switching devices, which allows to increase the efficiency of work.OBJECT. Timely detection of defects of contacts and contact connections of low-voltage switching devices to prevent emergencies.METHODS. Determination and control of technical condition of electrical equipment, contacts and contact connections of apparatuses in real time by means of indicators and thermal imaging control.RESULTS. The values of contact heating temperatures from material and type of contact connections were analysed. The criteria for estimation of the state of contacts of switching devices with the help of indicators of their state have been determined. The optimum values of loading coefficients of the circuit breaker in moulded case VA04 and contactors KMI and KTI are obtained. Emergency cases at the industrial object are shown, which prove the necessity of application of indicators and thermal imaging control as one of the tools of automation of technical condition control of low-voltage electrical equipment.CONCLUSIONS. The offered noncontact method of estimation and control of technical condition of electrical equipment, contacts and contact connections of devices in real time with the help of indicators and thermal imaging control allows both to receive data in real time mode and to increase inter-repair periods for power equipment and to increase reliability of operation of the whole system.

Surface Wear Monitoring System of Industrial Transformer Tap-Changer Contacts by Using Voice Signal

Surface wear of the tap-changer contacts of industrial transformers (due to frequent switching times) easily leads to operation failure of industrial transformers, which affects the safety and stability of the transmission network. In this paper, an intelligent voice signal monitoring system was proposed for the abnormal condition (surface wear) of tap-changer contacts. This monitoring system was composed of a voice signal acquisition system, voice analysis system and voice processing system. First, the voice signal of the tap-changer contacts was collected, and the collected voice signal was analyzed in the time domain and the frequency domain. Secondly, the characteristic curve of the voice signal was proposed, and the voice curve was compared with that of the normal operation state. In this case, the running state and surface wear abnormal situation of the tap changer could be monitored and determined, and the cause of the abnormal state could also be further analyzed. This method solved the surface wear problem of the tap changer in industrial transformers, which could be not monitored effectively in real time. This method improved the operational reliability of industrial transformers and had high economic and social benefits.

The Role of Mitochondrial in Intestinal Epithelial Barrier Dysfunction during Inflammatory Bowel Disease

Inflammatory bowel diseases are widely spread in industrial countries with every 20th citizen being affected. Dysregulation of epithelial barrier function is considered to play a key role in the development of inflammatory bowel diseases. Intestinal epithelium permeability depends mostly on the condition of intercellular contacts and epithelial cells' renewal ability. Mitochondria participate in the regulation of various intracellular processes besides performing the energetic function. Recent data indicate the potential role of mitochondria in intestinal epithelial barrier regulation and inflammatory bowel diseases onset. Mitochondrial dysfunction may be one of the reasons for disruption of the structure of tight junctions and the cytoskeleton of intestinal epithelial cells, as well as a decrease in the ability of the epithelial lining to self-renewal. All this leads to a decrease in the barrier function of the intestinal epithelium and the development of inflammatory bowel diseases. Nevertheless, the mechanisms of these processes are still unclear and further research is required.

On-Load Tap Changer Internal Contact Health Assessment Based on Ion Detection in Oil

Internal contact deterioration causes most electrical faults in on-load tap changers (OLTCs), which are difficult to diagnose promptly and accurately by traditional methods. This paper proposes a novel approach for internal contact condition evaluation based on metal ion detection. The variation of metal ions under the action of DC breakdown and natural corrosion for metal contacts with different materials are experimentally studied first. The formation mechanism of metal ions indicates that electric erosion is the primary cause of the short-term increase of characteristic ions. In addition, both chemical corrosion and electrochemical corrosion play a significant role in the long-term growth of metal ions. Based on the assumption of maximum damage to OLTC contacts, the characteristic metal ion concentration when the contacts require mandatory replacement is calculated. An early warning method for the damage condition of the internal contacts is proposed by combining the accumulated metal ion concentration and the relative metal ion growth rate. An on-site fault transformer case demonstrates that the multilevel warning value can well meet the requirements for the health status assessment of OLTC’s internal contacts.

Nanoscale probing of surface potential landscape at MoS2/BP van der Waals p–n heterojunction

2D van der Waals heterostructure paves a path towards next generation semiconductor junctions for nanoelectronics devices in the post silicon era. Probing the band alignment at a real condition of such 2D contacts and experimental determination of its junction parameters is necessary to comprehend the charge diffusion and transport through such 2D nano-junctions. Here, we demonstrate the formation of the p–n junction at the MoS2/Black phosphorene (BP) interface and conduct a nanoscale investigation to experimentally measure the band alignment at real conditions by means of measuring the spatial distribution of built-in potential, built-in electric field, and depletion width using the Kelvin probe force microscopy (KPFM) technique. We show that optimization of lift scan height is critical for defining the depletion region of MoS2/BP with nanoscale precision using the KPFM technique. The variations in the built-in potential and built-in electric field with varying thicknesses of MoS2 are revealed and calibrated.

Simulation of transient dose rate effect on analog phase locked loop

The transient dose rate effect (TDRE) on analog phase locked loop (PLL) is presented in this paper. New TDRE models of NMOS and PMOS are proposed through the combination of SPICE and Sentaurus TCAD, which improve a previous modeling method and especially incorporate the effects of the Length/Width ratio of transistors, resistance network of the substrate, and bias condition of contacts. The primary photocurrents in TDRE models, calculated by TCAD, are successfully fitted by double-exponential functions. Firstly, the TDRE of each PLL's sub-circuit is simulated. Then, the global effect of the PLL is simulated and the coupled relationship among sub-circuits is analyzed. Simulation results indicate that the current-based charge pump and voltage-controlled oscillator are sensitive to TDRE, and there is a significant coupled relationship between the two sub-circuits. On the contrary, the phase frequency detector shows low sensitivity to TDRE. Lastly, as two Radiation-Hardened-By-Design (RHBD) methods, using the voltage-based charge pump and using the voltage-controlled oscillator with a large drive current are proved to be effective in improving the TDRE of PLL.

LANGUAGE CONTACTS IN KAZAKHSTAN: THE LANGUAGE OF MULTILINGUAL YOUTH

This article examines the condition of language contacts in Kazakhstan. In particular, the issue of language contacts in higher educational institutions, where the main disciplines related to the majors in the country are taught in English. Now the number of such educational institutions is growing. In order to predict the occurrence of language contacts in these institutions, the degree of their influence on each other in the future, first of all, a study and analysis of students’ conversations in real situations were carried out. Research questions are: What languages do students want to use in different situations, and how do different situations affect their language choices? How and in what direction does the use of languages change during a conversation? The main goal of the study is to determine the functions of the Kazakh, Russian and English languages, which are currently widely used in Kazakhstan. Moreover, the study aims to find out how (how often) and where Kazakhs who graduated from Kazakh schools can use these languages. By responding to these questions, the author analyzes the reasons why young people use different languages in different situations.

Application of Frequency Response Analysis Technique to Detect Transformer Tap Changer Faults

Power transformers are located in the electrical transmission and distribution networks where different voltage levels are needed. The turn ratio of the low voltage and high voltage windings is mechanically controlled by an on-load tap changer or de-energized tap changer. As the tap changer is the transformer’s only moving part, it is highly susceptible to mechanical failure and aging degradation. While some diagnostic tools have been used to determine the mechanical condition of tap changer contacts, not much attention was given to use the frequency response analysis to diagnose the transformer’s tap changers’ mechanical integrity. This paper is taking one step forward into maturing the application of the frequency response analysis (FRA) technique to detect transformer tap changer faults. In this regard, two common tap changer faults are created, and experimental testing for four FRA test configurations is conducted. For a better understanding of the tap changer fault mechanism, an electrical equivalent circuit model is proposed and designed using Simulink. The simulation and implementation of the equivalent circuits using MATLAB\R2018a.

Identity under the shadow of profound intellectual disability – on the need for support, mapping of issues and scientific considerations

Everyone has the right to participate in social life regardless of personal situation, level of psychosocial functioning, gender, race or type of disability. The inherent condition of interpersonal contacts, taking place in the social space and constituting the basis of social life, is the desire to establish social relations and perceiving another participant in this process as an exceptional, original component. According to this, every person has the right to participate actively in social life, to be a part of it as “I” in order to create “we”. The aim of the article is to discuss and propagate scientific considerations about the possibilities and limitations of supporting the process of shaping the identity (personal and social) of people with profound intellectual disabilities. The article has an analytical character and aims to map the identity of people with profound intellectual disabilities in scientific and practical studies. It identifies areas and the type of support that will contribute to the development of the psychosocial identity of individuals with profound intellectual disabilities. It also presents factors resulting from the specificity of profound intellectual disabilities which may hinder the process of carrying out assistance for the given group by the supportinstitutions.

Online Assessment of Contact Erosion in High Voltage Gas Circuit Breakers Based on Different Physical Quantities

In this paper, an effort has been made to evaluate the online condition of arc contacts as a vital component of interruption chamber in high-voltage puffer-type SF6 circuit breakers. The relationship between eroded mass caused by short-circuit current interruption and different thermal stress indices, such as transferred electrical charge, current squared, and arc energy, is investigated by performing many experiments with different current amplitudes and arcing times. It is demonstrated that none of the known indices can solely determine mass erosion caused by the current interruption. Therefore, the equations including two of the defined parameters are proposed to evaluate mass erosion. The method using arc energy and transferred electrical charge owns the highest accuracy in evaluating mass loss. However, considering the complexity of arc voltage measurements, a second method using current and arcing time can be also utilized. In addition, the development of erosion during the lifetime of arc contacts is studied. It is shown that arc roots tend to form on new uneroded areas of the contacts during current interruption, resulting in different erosion rates between the first few and subsequent interruptions due to change of morphology of the contacts after the first few switching operations.

Analysis and optimization of alloyed Al-p+ region and rear contacts for highly efficient industrial n-type silicon solar cells.

This paper aims to develop high quality screen-printed Al emitters and improve the interface condition of rear contacts in industrial silicon solar cells. We propose to introduce an ultra-thin SiO2 buffer layer between the silicon bulk and metal contact during the fabrication process. A post-annealing strategy is adapted to further modify the Al doping profiles. The experimental results show that the effects of this oxide layer on migrating the nonuniformity of Al-p+ region and decreasing the defects at the metal–silicon interface are significant. The recombination velocity of contacts, which is extracted from the measured Srear by an analytical model, exhibits a decrease by 90.8% and the series resistance is reduced by 60.3% for the improved contacts compared to the conventional screen-printed contacts. Finally, this technique is applied to large-area (156 × 156 mm2) industrial n-type silicon solar cells and leads to a 2.18% increase in average cell efficiency, including a 12.82 mV increase in open-circuit voltage Voc and 0.99 mA cm−2 increase in short-circuit current density Jsc compared with solar cells fabricated by a standard industrial process. A 19.16% efficient cell with a Voc of 637.47 mV is achieved.

Investigation of cathode spot characteristics in vacuum under transverse magnetic field (TMF) contacts

With the continuous improvement of current levels in power systems, the demands on the breaking capacity requirements of vacuum circuit breakers are getting higher and higher. The breaking capacity of vacuum breakers is determined by cathode spots, which provide electrons and metal vapor to maintain the arc. In this paper, experiments were carried out on two kinds of transverse magnetic field (TMF) contacts in a demountable vacuum chamber, the behavior of the cathode spots was recorded by a high-speed charge-coupled device (CCD) video camera, and the characteristics of the cathode spots were analyzed through the image processing method. The phenomenon of cathode spot groups and the star-shaped pattern of the spots were both discovered in the experiment. The experimental results show that with the condition of TMF contacts the initial expansion speed of cathode spots is influenced by some parameters, such as the tested current, contact gap, the structure of the contact, the contact diameter, the number of slots, etc. In addition, the influence of the magnetic field on the formation of the cathode spot groups, the distribution, and the dynamic characteristics of the cathode spots were analyzed. It is concluded that the characteristics of the cathode spots are due to the effect of the magnetic field on the near-cathode plasma. The study of the characteristics of cathode spots in this paper would be helpful in the exploration of the physical process of vacuum arcs, and would be of guiding significance in optimizing the design of vacuum circuit breakers.

Significance of mandibular molar replacement with a dental implant: a theoretical study with nonlinear finite element analysis

BackgroundDental implants are frequently applied to unilateral defects in the mandible. However, implant placement in the molar region of the mandible can be difficult due to anatomical structure. The aim of this study was to evaluate the distribution of occlusal force in a mandibular shortened dental arch (SDA) with implants.MethodsThree-dimensional finite element (FE) models of the mandible with varying numbers of teeth and implants were constructed. Models Im6 and Im67 contained one and two implants in the defect of the left molar region, respectively. Models Im456 and Im4567 contained three and four implants in the defect of the left premolar and molar regions, respectively. Model MT67 contained a defect in the molar region with no implant placed. Model MT7 represented natural dentition without a left second molar, as a control. Modification of the condition of occlusal contacts assuming the intercuspal position was performed before analysis under load 400 N; therefore, the load condition as total force on the occlusal surface was 400 N. FE analyses were subsequently performed under load conditions of loads 100, 200, and 800 N. The distribution of reaction forces on the occlusal surface and the mandibular condyle was investigated.ResultsForce distribution in models Im67 and Im4567 appeared to be symmetrical under all load conditions. Occlusal force distribution in models Im6 and Im456 was similar to that in model MT7. However, the occlusal force at the second premolars on the defect side in those models was larger under loads 100 and 200 N. Conversely, the occlusal force on the first molars was much larger than that in model MT7 under load 800 N.ConclusionsWithin the limitations of this theoretical study, we demonstrated that restoration with the same number of implants as missing teeth will show almost symmetric occlusal force distribution, and it will produce less biomechanically stress for a unilateral defect of the mandible. However, if restoration of a missing second molar with an implant is impossible or difficult, then an SDA with implants may also be acceptable except for individuals with severe bruxism.

Novel high‐frequency‐based diagnostic approach for main contact assessment of high‐voltage circuit breakers

Maintenance and repair of circuit breakers (CBs) due to their protective role in the power systems is the centre of attention and assessing their condition is tremendously important. The interruption chamber of the CBs including main contacts is highly subjected to erosion over time due to friction, and excessive heat produced by an arc during the interruption of the currents. This study presents a new high-frequency (HF) non-intrusive diagnostic technique for the deterioration of contacts used in high-voltage CBs. The most striking result to emerge from the investigations is that the resonance frequency highly relies on the condition of contacts. The proposed approach is implemented in Computer Simulation Technology Studio Suite software and compared with the measured data obtained through the static resistance measurement. In addition, a HF model based on the transmission line theory has been developed for the interruption chamber of CBs. The comparison of the obtained results via a novel HF-based approach with the experimental data validates the feasibility and accuracy of this approach in analysing the ablation of contacts used in the interruption chamber of CBs.

The Phenomena of Interlanguage Interference at the Morphemic Level

<p>The phenomena of language interference at the morphemic level as a type of grammatical interference were not accepted by the linguists who considered morphological interference impossible. However, there are linguists who claim that in language contacts morphological systems of languages affect each other and they consider it quite acceptable.</p><p>Divergences in morphological systems of contacting languages cause morphological interference in bilinguals’ speech. Morphological peculiarities of contacting languages explain the reason of such deviations. Morphemes are two-sided units which are identified by the unity of phonetic or exponential (expository) and semantic features. Due to major differences in morphological structures of English and Azerbaijani languages, Azerbaijani students confuse English morphemes with the morphemes in their native language that is reflected in the phenomena of morphemic interference in their speech. So, in the study of morphemic interference it is significant to consider the types of contacting languages that is the basis of typological research in condition of bilingualism and language contacts.</p>

Pemanfaatan e-commerce dan m-commerce dalam bisnis di kalangan wirausahawan perempuan

This study discusses the use of e-commerce and m-commerce by female entrepreneurs, the majority was housewives. This study uses a qualitative method for exposing a phe-nomenon and the behavior that occurs. It uses descriptive design which allows for the study of profound and piercing the target. Thus, this research modle is the linear snowball to get 100 female entrepreneurs who do business with e-commerce and m-commerce. The findings show that some female entrepreneurs take advantage of e-commerce for retail sales, wholesalers, agents and distributors of a product / service and also in some remote areas, e-commerce, they can help some entrepreneurs to jump-start their business in a way to explore e-commerce for looking for a supplier. Utiliza-tion of e-commerce is relatively easier for the beginner entrepreneurs in the condition of contacts through mobile that is a demand for the products they offer. It suggests that further study can be done discussing the similar e-commerce which aims to support the emergence of women entrepreneurs as a reinforcement of the household finances with-out abandoning their responsibilities as a mother

An Overview of Dynamic Contact Resistance Measurement of HV Circuit Breakers

With the deregulation of the electrical power industry, utilities and service companies are operating in a changing business environment. High voltage circuit breakers are extremely important for the function of modern electric power supply systems. The need to predict the proper function of circuit breaker grew over the years as the transmission networks expanded. The maintenance of circuit breakers deserves special consideration because of their importance for routine switching and for protection of other equipments. Electric transmission system breakups and equipment destruction can occur if a circuit breaker fails to operate because of a lack of preventive maintenance. Dynamic Contact Resistance Measurement (DCRM) is known as an effective technique for assessing the condition of power circuit breakers contacts and operating mechanism. This paper gives a general review about DCRM. It discusses the practical case studies on use of DCRM for condition assessment of high voltage circuit breakers.

스퍼 기어 시스템의 음향 신호와 비 유막 두께(Specific Film Thickness)의 상관관계에 관한 실험적 연구

Gear transmission system is widely applied in engineering. As the problem of contact fatigue, wear, lubrication failure etc, the condition of gear teeth contacts will be worse. The vibration and sound signals in the gear system will be affected by the some failures like scuffing, abrasive wear and spalling due to the deterioration of gear teeth surface. By studying the estimation of specific film thickness, measurement of reduction in tooth thickness, visual examination of wear mechanisms on the gear teeth and their effects on the statistical parameters of vibration and sound signals, the research obtained the satisfactory results on accessing the surface fatigue wear in a spur gear system. The paper utilizes the relationship between statistical parameters obtained from sound signals and Stribeck curve to confirm the hypothesis of dependency of surface fatigue wear, specific film thickness.

DEVLOPEMENT OF THE DYNAMIC RESISTANCE MEASUREMENT (DRM) METHOD FOR CONDITION ASSESSMENT OF OLTC

Many failure of power transformer are due to the failure of On Load Tap Changer. If we apply some diagnosis test during the function of OLTC, some of degradation effects can be assess. This paper concentrates on OLTC diagnostic method based on the measurement of dynamic resistance. Some experiments were applied to the OLTC using DRM. With the result of these experiments, it becomes possible to assess the condition of OLTC contacts and transient resistance.