Contact System Research Articles

Histidine-Rich Glycoprotein Modulates the Toxic Effects of High-Dose Polyphosphate in Mice.

Polyphosphate (polyP), a procoagulant released from platelets, activates coagulation via the contact system and modulates cardiomyocyte viability. High-dose intravenous polyP is lethal in mice, presumably because of thrombosis. Previously, we showed that HRG (histidine-rich glycoprotein) binds polyP and attenuates its procoagulant effects. In this study, we investigated the mechanisms responsible for the lethality of intravenous polyP in mice and the impact of HRG on this process. The survival of wild-type or HRG-deficient mice given intravenous synthetic or platelet-derived polyP in doses up to 50 mg/kg or saline was compared. To determine the contribution of thrombosis, the effect of FXII (factor XII) knockdown or enoxaparin on polyP-induced fibrin deposition in the lungs was examined. To assess cardiotoxicity, the ECG was continuously monitored, the levels of troponin I and the myocardial band of creatine kinase were quantified, and the viability of a cultured murine cardiomyocyte cell line exposed to polyP in the absence or presence of HRG was determined. In HRG-deficient mice, polyP was lethal at 30 mg/kg, whereas it was lethal in wild-type mice at 50 mg/kg. Although FXII knockdown or enoxaparin administration attenuated polyP-induced fibrin deposition in the lungs, neither affected mortality. PolyP induced dose-dependent ECG abnormalities, including heart block and ST-segment changes, and increased the levels of troponin and myocardial band of creatine kinase, effects that were more pronounced in HRG-deficient mice than in wild-type mice and were attenuated when HRG-deficient mice were given supplemental HRG. Consistent with its cardiotoxicity, polyP reduced the viability of cultured cardiomyocytes in a dose-dependent manner, an effect attenuated with supplemental HRG. High-dose intravenous polyP is cardiotoxic in mice, and HRG modulates this effect.

Testing of Permeability of RFID Access Control System for the Needs of Security Management

Access control systems are part of the overall protection of objects. It is often the first system with which it is necessary to start the contact system; therefore, it is necessary to ensure its proper functioning. In the event of a malfunction, it can cause downtime in production, and it is triggered by a bad replacement of workers. Access control systems have their own specificities that need to be considered when designing security. Poor selection of access control devices can cause inefficient system functionality, resulting in downtime and loss. Based on experimental testing and related work in access control systems, this paper discusses the possibilities of testing the throughput of access control systems. The manuscript presents the design of a unique test device that can be used in the assessment of the reliability and throughput of access control systems. With the help of tests, we were able to determine the probability of downtime due to inappropriately set time intervals for changing employees on a work shift.

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.

A fast solution method for the interaction between the rigid overhead contact system and pantograph on long railway lines

Currently, simulation is an important method for studying the interaction between the pantograph and the rigid overhead contact system (ROCS). However, when solving the ROCS model for long railway line scenarios, the problem of intractable or inefficient computation arises due to the excessively large size of the matrix. To address this issue, this paper proposes a method called: a fast solution method for the interaction between the rigid overhead contact system and pantograph on long railway lines based on a coupled window approach (hereinafter referred to as: CW-RCP). The CW-RCP method utilises coupled windows to simulate the ROCS model, effectively limiting the length of the ROCS involved in each computation. This approach greatly enhances computational efficiency. After deriving the dynamic equations and solving equations of the CW-RCP method in detail, the effectiveness, advantages, and applications of this method are discussed. The results demonstrate that the CW-RCP method can effectively compensate for the computational inefficiencies of traditional methods without compromising computational accuracy.

Investigation of lubricant viscosity and third-particle contribution to contact behavior in dry and lubricated three-body contact conditions

The generation of third particles and change in viscosity lead to the gradual degradation of the performance of the machine interface. The generation of third particles may come from wear debris or environmental particles, which form a three-body contact system at the contact interface. The viscosity of the lubricant will also change with the long-term operation of the components. This paper uses a three-body lubrication model to study the influence and interaction of lubricant viscosity change and the presence of third particles on the contact characteristics, including the real contact area, the particle contact area ratio, the solid load percentage, the film thickness, and the evolution of the lubrication regime. The results show that when the interface is in a three-body mixed lubrication regime, the dimensionless total real contact area increases with the increase in particle size and density at the same lubricant viscosity, while the trend is the opposite in dry contact and boundary lubrication interfaces. When viscosity decreases, a three-body contact interface is more prone to entering boundary lubrication than a two-body contact interface, resulting in surface damage. Regardless of surface roughness, particle size, and dry or lubricated contact conditions, the turning point of the contact area (TPCA) phenomenon is usually when the ratio of particle size to surface roughness is 0.8–1.3. Under the same ratio of particle size to surface roughness, the critical load of the TPCA phenomenon increases with the increase in third-particle size and surface roughness, but decreases with the increase in lubricant viscosity and particle density.

Combinatorial and algorithmic complexity of crystal structures

Research subject. Numeral indexes describing the complexity of the system of contacts between structural units in crystal structures. Aim. Development of a complexity index for the system of contacts between periodic structural units based on the indices available for those between structural units in island (molecular) structures. Materials and methods. Structural data were selected from the COD, AMCSD, and CSD crystallographic databases. The system of contacts in the structures was analyzed by the Voronoi–Dirichlet polyhedra (VDP) method in the ToposPro software package. Results. The method of topological analysis of the system of contacts in molecular crystals was adapted to all heterodesmic crystal structures and tested on the structures of compounds of several classes. Target complexity indices were developed. Conclusions. Networks of contacts between periodic structural units are low-dimensional. A generalized structural class for such networks can be derived from the original crystal structure data. The algorithmic complexity of heterodesmic structures is subadditive, in contrast to superadditive combinatorial complexity. For the first time, the number of bearing contacts was calculated between periodic structural units, reflecting the algorithmic complexity of the structure at the appropriate level of structural description.

IMPACT OF CONTACT SYSTEM ON CARDIOVASCULAR DISEASES

Contact and intrinsic coagulation pathway components are involved in pathological thrombus formation. In addi­tion to coagulation, contact system activation is involved in anti/profibrinolytic and inflammatory processes that can contribute to the atherosclerotic and thrombotic en­vironment, leading to cardiovascular diseases. This lite­rature review concerns the role of the contact system on cardiovascular diseases and accentuates the potential of coagulation factors FXII (FXII) and FXI (FXI) as targets for antithrombotic therapy.

Thermally stable Mo-Co-B thin film metallic glass as a potential diffusion barrier in Cu/Si contact system

Thin film metallic glass (TFMG) has demonstrated significant potential for applications in the semiconductor industry. In this work, fully amorphous Mo-Co-B thin films with a smooth surface and dense microstructure were prepared through magnetron sputtering. The thermal stability and diffusion barrier performance of the Mo-based TFMG were evaluated through vacuum annealing at temperatures ranging from 300 to 800 °C for 30 min. Nanoindentation tests were conducted to investigate the evolution of mechanical properties with annealing for the Mo-based thin film. When subjected to annealing at temperatures below 700 °C, the Mo-based thin film retained its fully amorphous structure. It displayed enhanced hardness and Young's modulus due to the annihilation of free volume with annealing. Increasing the annealing temperature to 700 °C and 800 °C resulted in surface oxidation and crystallization of the Mo-based TFMG, respectively, leading to a continuous decline in its mechanical properties. When employed as the diffusion barrier between Cu and Si, the Mo-based barrier layer effectively blocked the diffusion of Cu atoms through the barrier at temperatures below 800 °C. The failure of the barrier occurred at 800 °C due to the crystallization of the amorphous phase. Such excellent diffusion barrier performance of the thermally stable Mo-Co-B TFMG makes it a promising candidate as the barrier material in Cu metallization.

Inter-α-trypsin inhibitor heavy chain 4 (ITIH4) as a compensatory protease inhibitor in hereditary angioedema

BackgroundHereditary angioedema (HAE) is a genetic disorder that manifests as recurrent angioedema attacks, most frequently due to absent or reduced C1 inhibitor (C1-INH) activity. C1-INH is a crucial regulator of enzymatic cascades in the complement, fibrinolytic, and contact systems. Inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) is an abundant plasma protease inhibitor that can inhibit enzymes in the proteolytic pathways associated with HAE. Nothing is known about its role in HAE. ObjectiveInvestigate ITIH4 activation in HAE, establish it as a potential biomarker, and explore its involvement in HAE-associated proteolytic pathways. MethodsSpecific immunoassays for non-cleaved ITIH4 (Intact ITIH4) and an assay detecting both intact and cleaved ITIH4 (Total ITIH4) were developed. We initially tested serum samples from HAE patients (n=20), ACEI-induced edema patients (ACEI) (n=20), and unknown HAE patients (U-HAE) (n=20). Validation involved an extended cohort of 80 HAE patients (60 type I, 20 type II), including samples taken at attack and quiescent disease periods, as well as 100 healthy controls. ResultsIn 63% of HAE patients, the Intact ITIH4 assay showed lower signals than the Total ITIH4 assay. This difference was not observed in ACEI and U-HAE patients. Western blotting confirmed cleaved ITIH4 in low-Intact ITIH4 samples. In serum samples lacking intact endogenous ITIH4, we observed immediate cleavage of added recombinant ITIH4 suggesting continuous enzymatic activity in the serum. Confirmatory HAE cohort analysis revealed significantly lower intact ITIH4 levels in both HAE type 1 and type 2 patients compared to controls, with consistently low Intact/Total ITIH4 ratios during clinical HAE attacks. ConclusionThe disease-specific low intact ITIH4 levels highlight its unique nature in HAE. The results suggest that ITIH4 may exhibit compensatory mechanisms in HAE, suggesting its utility as a diagnostic and prognostic biomarker. The variations during quiescent and active disease periods raise intriguing questions about the dynamics of proteolytic pathways in HAE.

Influence of High-Speed Railway Subgrade Form on the Aerodynamic Characteristics of the Overhead Contact System Positive Feeder in the Gale Area

Influence of High-Speed Railway Subgrade Form on the Aerodynamic Characteristics of the Overhead Contact System Positive Feeder in the Gale Area

Exploring factors influencing machine milk yield of dairy cows in cow-calf contact systems: Cow behavior, animal characteristics, and milking management

The objective of this study was to explore factors contributing to low machine milk yield of cows with cow-calf contact. Danish Holstein dairy cows were assigned to 1 of 3 cow-calf contact treatments: full-time with the calf (n = 24), part-time with the calf between morning (a.m.) and afternoon (p.m.) milking and separated overnight (n = 23), or separated from the calf at birth (n = 23). Behavior of cows (stepping and kicking in the parlor) and milking procedures (teat or udder stimulation frequency, preparation duration) were recorded at a.m. and p.m. milking on 2 d during wk 4 and 6 of the treatment period (8 milkings per cow). Full-time cows had the lowest machine milk yields (mean ± SE; 6.1 and 6.0 ± 0.7 L at a.m. and p.m. milking, respectively), whereas part-time cows had similar yield to no-contact cows at a.m. milking (19.6 ± 0.7 L) and similar yield to full-time cows at p.m. milking (6.4 ± 0.7 L). Lower machine milk yields in cows with calf contact could not be fully attributed to milk consumption by the calf; however, they also could not be explained by differences in cow parity, calf sex, milking procedures (stimulation frequency; preparation duration), or stepping and kicking (restless) behavior at milking. All cows showed more restless behavior at p.m. milking, which weakly negatively affected machine milk yield, but this was unrelated to stimulation frequency in cow-calf contact cows, indicating that there may be other sources of discomfort or stress at the time of milking for these cows. Part-time versus full-time calf contact improved daily machine milk yields, but low machine milk yield issues merit further research so that cow-calf contact systems can be sustainable for producers.

Modeling of Photovoltaic Characteristics of a TiO<sub>2</sub>/Porous-Si/Si-Based Heterojunction Solar Cell

This work is focused on the study of photosensitive structures based on porous Si and film TiO2, which are promising for solar energy. For numerical simulation of the transportation and accumulation of charge carriers in the considered heterostructure, the drift-diffusion approximation of the semiclassical approach was proposed. A device scheme of a solar cell model based on TiO2/porous-Si/Si heterostructures is proposed. Production of photoconverters of solar cells based on the TiO2/porous-Si/Si heterostructure can be carried out according to the standard method supplemented by additional technological operations. Ohmic contacts are formed in the upper and lower parts of the structure above the TiO2 and Si layers. The strip system of contacts is a contact grid, with hatching, the surface coefficient should not exceed 5%. The thickness of the applied layer of photoresist should be 1 μm. Using the PC1D program, the light characteristics of the fabricated structure were calculated (open circuit voltage VOC, short circuit current ISC, fill factor FF and efficiency η), and current-voltage characteristics were plotted. The influence of the thickness and doping level Nd and Na of porous Si and TiO2 layers on the productivity of a heterojunction solar cell TiO2/porous-Si/Si was studied in order to obtain a device with a good conversion efficiency. It was found that the energy conversion efficiency of a TiO2/porous-Si/Si solar cell can reach 22.5 %. Based on the optimized simulation conditions, it was found that the maximum solar cell efficiency is achieved at thicknesses of 100 and 200 nm and donor concentration of Nd=1∙1017 cm-3 and acceptor concentration of Na=1∙1018 cm-3 for TiO2 and porous Si buffer layer, accordingly.

A permanent insulator system for hydrometallurgy with a significant increase in electric efficiency and without short circuit

A permanent insulator system for hydrometallurgy has been developed with a significant increase in electric efficiency and without short circuits. The system consists of a double electric contact point for each cathode and anode and a new design of the insulating and contact system of the electrodes. The combination of these technologies provides a more uniform electric density inside each cathode and anode, in each cell, and also for the whole electric circuit in the cellhouse. Keeping a consistent maximum performance necessitates using parts with extreme durability against chemical attacks and short circuits. Hence, a comprehensive research into chemical stoichiometry and the behaviour of different molecules resulted in the development of an outstanding chemical resistance level to sulfuric acid and extremely high temperatures throughout the entire hydrometallurgical process. Field observations show that this formulation has been able to resist up to 19 years of continuous operation without maintenance. The goal of these developments combined with a new contact system was to reduce any type of short circuit by 70 to 80%, which in turn increases the electric current effectiveness by 8 to 10%. As a result, higher contact efficiencies have doubled the lifetime of the cathode and anode with this system. Consequently, the overall electric efficiency in a refinery cellhouse can be improved by 10-12%. Observations from real-world applications over the past decades have proven the efficiency of the earlier versions of this new concept. The system was found to be applicable to any type of contact system and has been used in various hydrometallurgical processes with great success. With the increasing price of energy and CO2 production, it has become more important to operate ecologically and efficiently to maximize profitability and this permanent insulator system can address many challenges which lead to a more efficient and cost-effective process.

Wear resistance of extruder parts in the production of polymer nanomodified products

Extrusion equipment is widely used in the production of polymer materials. One of the urgent questions that arises when studying the processes of obtaining polymer products by the extrusion method is the question of studying abrasive wear, which may depend on the efficiency of the equipment, the duration and reliability of its work. In the context of abrasive wear, the process that needs attention is the extrusion of polymer materials with carbon nanotubes. The purpose of this work is to develop a numerical method for determining the evolution of abrasive wear of the equipment of the extruder working area in the process of processing nanomodified polymer granules and determining the life cycle of this equipment with in order to increase the parameters of their durability. The specific objectives of the study include: 1) Determination of the influence of the content of CNTs in PVC on the rate of wear of the steel surface of the extruder; 2) Analysis of the dependence between friction and the content of CNTs in the polymer composite; 3) Establishing optimal extrusion conditions to minimize abrasive wear of the steel surface; 4) Comparison of simulation results with experimental data to check the reliability of the model. The work is aimed at understanding the processes that occur during the extrusion of nanocomposites and their impact on the wear resistance of equipment materials, which can contribute to the improvement of technological processes and ensure longer and more efficient operation of extruders in production conditions. It has been established that the processes of extrusion processing of polymer nanoreinforced composites can be effectively studied by developing and implementing numerical models that take into account the interaction of all physical and mechanical parameters of a representative volume of the contact zone of the equipment with the polymer and the nanotube with the adhesive layer. In this work, a model for determining the physical and mechanical properties of the interface layer between the CNT and the polymer array is constructed and implemented. The technique for determining the properties of the nanotube-polymer interface is integrated into the APROKS system for analyzing the stress-strain state of nanomodified polymer materials. Based on a multilayer isoparametric FE, a series of numerical experiments were carried out to simulate the process of abrasive wear of the material of equipment elements in the extruder working area. The possibility of a detailed study of the processes of nonlinear contact interaction of nanotubes with an interface layer with equipment elements of the extruder working area based on multilayer FE has been confirmed. Diagrams were obtained that determine the service life of equipment in the working area of the extruder depending on the volume concentration of carbon nanotubes in the polymer at different levels of operating pressure in the “nanotube – polymer – equipment” contact system. It is advisable to use the proposed methodology in the development of information support systems for the life cycle of operation of equipment in the working area of extruders intended for the production of nanomodified polymer products.

EXPERIMENTAL STUDY AND MONITORING OF TEMPERATURE AND SURFACE ROUGHNESS AND MICRO-HARDNESS OF THE WHEEL–RAIL CONTACT IN THE DESERT REGION OF THE OUARGLA TRAMWAY

Public transport via trams has become increasingly important in daily life to meet the growing demand for economic and environmental considerations. In order to ensure the safety of the railway system and reduce service costs, it is necessary to understand the tribological behavior of the system. There are various types of damage such as fatigue, wear, and cracking that can harm the wheels and rails. To determine the wear mechanisms and identify the situations in which wear movements occur, it is crucial to monitor factors such as temperature, surface roughness, and contact micro-hardness between the wheel and the rail. The objective of this study is to analyze the tribological behavior and the impact of climatic conditions on the wheel–rail contact system in the desert area of the Ouargla tramway in Algeria. To achieve this, an intelligent sensor programmed by a microcontroller was utilized to measure the temperature of the wheel–rail contact. Additionally, a hardness tester was used to measure the micro-hardness of the rail, and a roughness tester was utilized to monitor the surface condition of the rail. The measured temperature values during the passage of the tramway varied between ambient temperature and a temperature of 450∘C. The micro-hardness values ranged from 270 Hv to 440 Hv, and the roughness values varied between 0.4[Formula: see text][Formula: see text]m and 2.7[Formula: see text][Formula: see text]m.

Dairy farmers’ preferences for immediate versus late calf separation

The practice of separating calves from their dams right after birth is one of the main dairy cattle welfare concerns among the public. Farmer perceptions about the practice and the available alternative contact systems in the US are however, not well understood. Using data from a sample of Wisconsin dairy farmers, the study examines farmer preferences for different prolonged (relative to immediate separation) contact systems and the potential role of farm structural and individual-level specific factors. Four alternative hypothetical systems - free dam, half day, foster cow, and restricted suckling systems – differing on the basis of calf access to dam-were considered. The analysis controls for farm size, production system (conventional, organic, grazing), farmer socio-demographic characteristics in addition to farm animal welfare (FAW) perceptions. The findings indicate that amongst the set of alternative practices considered, foster cow system is most preferred alternative to the conventional early separation practised by most farmers. This is followed by restricted suckling systems. The least ranked alternative system is free calf-dam contact. The analyses further indicate that calf contact duration is negatively associated with herd size. Relative to conventional farms, calf-dam pairs on grazing, organic and mixed farms are less likely to be separated immediately after birth. Prolonged calf-dam contact is also prevalent amongst older farmers. Overall, the findings imply that farming system and structural considerations may be the key drivers of transition to prolonged contact systems in dairy production. Foster cow systems may offer the most feasible pathway for achieving this objective.

Effect of the daily duration of calf contact on the dam's ultradian and circadian activity rhythms

Cow-calf contact systems are attracting increasing interest among farmers and some are already being implemented into dairy farms. However, a comprehensive assessment of animal welfare in these systems is lacking. One reason for this is the large amount of time required for behavioral observations. However, the increased use of sensors in herd management assistance systems offers new opportunities for automated monitoring of animal welfare. For example, accelerometers can be used to collect activity data for a specific pattern analysis. In this study, ultradian and circadian rhythms of cows were analyzed. The degree of functional coupling (DFC; range of values: 0–1) expresses the extent to which the activity is cyclic to 24 h, and therefore harmonically synchronized with the periodicity of the environment. A DFC of 1 indicates complete adaptation of the cows' activity rhythm to the 24-h day. Additionally, the diurnality index (DI) is used to examine the distribution of diurnal and nocturnal activity. A DI of 1 indicates complete diurnal activity, whereas −1 indicates complete nocturnal activity. The rhythms of healthy and well-adapted animals show high adaptation to the 24-h day, whereas external or endogenous effects can interfere with these rhythms. Although contact with their calves allows cows to behave more naturally, it is possible that calves demanding their mothers' attention may affect the cows' rhythmicity, similar to other external factors. To test this hypothesis, 2 herds of German Holstein cows housed in a mirrored loose housing system were included in the study, which was conducted over 2 experimental periods. Three treatments were applied, differing in contact between cow and calf. The contact dams had either whole-day or daytime contact with their calves, and the no-contact cows were separated from their calves directly postpartum. Accelerometers were used to record and analyze the cows' activity between 59 and 83 DIM, thus excluding the calving and weaning phases. Generalized linear mixed models were used to estimate the effect of treatment (no, daytime, and whole-day contact) on DFC and DI, considering the effects of estrus, deviation of milking start in the evening, and parity (primi- vs. multiparous). Finally, the harmonic period lengths of the activity patterns were extracted to analyze the distribution of the primarily expressed period lengths of the different treatments. In general, the average activity patterns of the cows did not differ between the treatments. However, dams with whole-day contact showed a lower activity peak before milking but a higher activity after evening milking. Nevertheless, the DFC and DI were similar in each group. During estrus, the chance of a maximum DFC decreased and the DI increased. Whole-day contact dams showed the most significant harmonic periods (33 per cow). Nevertheless, the primarily expressed period length (3.4 h) was equal in each treatment. In conclusion, neither contact with the calf nor its daily duration affected the ultradian and circadian rhythms of dams compared with cows separated from their calf.

Research progress of direct contact heat storage based on phase change heat storage

AbstractPhase change heat storage presents a promising solution to address challenges related to new energy intermittency and waste heat recovery. However, for it to function as an effective energy hub, heat storage becomes crucial. Among the available options, the direct contact heat accumulator stands out due to its simple structure, substantial heat transfer area, and minimal heat transfer resistance, making it a favorable choice for enhancing energy storage rates. Although a great deal of research has been done on phase change materials and heat accumulators over the years, a systematic review of direct‐contact heat accumulators is lacking. This article reviews the related research on direct contact heat storage, aiming to summarize the research work on direct contact phase change heat storage systems. Various phase change materials (PCMs) for direct contact systems are analyzed, and the study of PCM melting crystallization behavior, heat transfer coefficients and system performance in direct contact systems is summarized, as well as the improvement methods for direct contact vessels and PCMs. It provides a useful reference for future research on direct‐contact heat storage systems.

Arcing Stabilization Effect and Ablation Characteristics for C–Cu Electrodes at Low Air Pressure

Arc ablation is a widespread problem in electrical contact systems. The fault of the system caused by arc ablation significantly restricts its lifespan. Facing the development goal of electrified aircraft and low vacuum high-speed railways, the problem of arc ablation at low air pressure cannot be ignored. In this paper, an experimental platform for arcing and ablation at low air pressure is built. The influence of low air pressure on the characteristics of arc ablation is explored. The results show that the stability of the arc column at low air pressure varies significantly. Under the condition of different air pressures, the traces and morphology in the ablation region of the electrode differ significantly. These are caused by Rayleigh-Taylor instability between the arc and air, and by the motion of the arc root which is driven by the arc column. Importantly, the low-pressure stabilization effect for the arc is found. The corresponding relationship between electrode ablation traces, surface morphology, and air pressure is revealed. The action mechanism of air pressure on the arcing process and ablation characteristics of the electrode are clarified. This research provides theoretical support for restraining arc ablation and prolonging the lifespan of the electrical contact system.

Digital Protocol to Record Occlusal Analysis in Prosthodontics: A Pilot Study.

Background: Digital technologies enable the accurate replication of occlusion, which is pivotal for stability in maximum intercuspation and dynamic occlusion. CAD softwares generates standardized occlusal morphologies requiring significant adjustments. The consideration of individual mandibular movements during restoration leads to better functional integration. This pilot study evaluates the efficacy of a novel, fully digital protocol for occlusal analysis recording in prosthodontics. Methods: Patients needing single or multiple metal-free restorations were included. Teeth underwent horizontal finish line preparation, while restorations on implants were either directly screwed or used multi-unit abutments. A digital impression (Trios 3 Intraoral Scanner) captured the mouth's elements. Dynamic occlusion was recorded via Patient Specific Motion (PSM). After the placement and functionalization of temporary restorations, subsequent scans included various elements, and CAD software (Dental system) was used for the restoration design. Restorations were milled in monolithic zirconia, pressed from CAD/CAM-milled wax, and sintered. Results: An evaluation of 52 restorations in 37 patients indicated high accuracy in restorations manufactured via the fully digital workflow. Monolithic zirconia was predominantly used. Subtractive (17.3%) and additive (7.7%) occlusal adjustments were mainly chairside. Conclusion: This study underscores the efficacy of meticulous verification measures and a centric contact system in reducing the need for clinical occlusal refinements in prosthetic restorations.