Comparison of Occlusal Parameters between Open Bite and Nonopen Bite Patients Using the T-Scan III System: A Pilot Study

Objective To evaluate and compare the first tooth contact region, occlusion time, time to generate total force, and force distribution between open bite (OB) and non-OB (NOB) patients at the maximum intercuspation position using the T-Scan III system. Materials and Methods Sixteen patients were divided into the OB and NOB groups (n = 8 for each group). The T-Scan III system was used to evaluate the first tooth contact region, occlusion time, time to generate total force, and force distribution. Statistical Analysis The mean patient age, overjet, overbite, occlusion time, and time to generate total force were compared between the groups by independent samples t-test. Relative force distributions between groups and among regions were compared by the Mann–Whitney U- and Kruskal–Wallis H-tests, respectively. A probability value of less than 5% (p < 0.05) was considered significant. Results Differences in the first tooth contact region between groups were observed. The molar region was the first tooth contact region in the OB group, while first tooth contact was observed in all regions in the NOB group. Neither the occlusion time nor the time to generate total force was significantly different between the groups (p > 0.05). The highest force distributions were observed in the molar regions in both groups. Significant intragroup differences were found among all regions (p < 0.05), except between the anterior and premolar regions in the NOB group (p = 0.317). Intergroup differences in the force distributions in the anterior (p = 0.000), premolar (p = 0.038), and molar (p = 0.007) regions were significant. Conclusion Unlike in the NOB group, in which first tooth contact occurred in every region, in the OB group, first tooth contact occurred only in the molar region. Compared with those in the NOB group, the force distributions in the OB group were approximately 1.5 times higher in the molar region but were significantly lower in the anterior and premolar regions.

Research of the Modes of Starting and Braking during Work of the Systems of Group Electric Drive of Mine Electric Locomotive with the Different Types of Electric Engines

In the article the results of research of work of mine electric locomotive are driven on condition of stability of the system "A wheel is a rail" on coupling of wheels of electric locomotive with rails. It is marked that work of mine electric locomotive transport is conditioned by the row of specific terms. It is indicated that for realization of the electromechanics systems of mine electric locomotives structures are used with the hauling electric engines of direct and variable current. During working as of mine electric locomotive an important question there is coupling of wheels of electric locomotive with rails. Investigation of worsening of coupling of wheel with a rail is an origin of processes of skidding in the mode of creation of tractive or юза force in the mode braking of electric locomotive, that influence negatively for other knots of hauling electromechanic. In turn stability of the system "A wheel is a rail" depends on the type of hauling electromechanic. At consideration condition of stability of electromechanic on coupling of wheels of electric locomotive with rails important is inflexibility of descriptions of hauling electric motors. What more inflexibility, the higher stability of the system "A wheel is a rail". More hard descriptions can be got in the system of electromechanic with hauling asynchronous engines that give an opportunity to use this fact for realization of proportional distribution of efforts between the wheelpairs of electric locomotive. The systems ticker-coil on speed allow to carry out distribution of hauling and brake efforts that is attached to the wheelpairs of electric locomotive, in accordance with distribution of efforts from these wheelpairs on rails, only after the beginning of processes of skidding or skidding. For the decision of this problem a sufficient condition there is a limit of currents of hauling electric motors on the set level. In this connection possibility of distribution of hauling and brake efforts appears at any moment to time. For the decision of task of rational distribution of efforts of electric locomotive, distribution of forces was analysed between his wheelpairs in the function of total force that pulls an electric locomotive on his coupling. On the basis of analysis an idea was got about the redistribution of loading on the axes of electric locomotive. This distribution is in direct ratio to his total tractive force and coupling height, and in inverse ratio to inflexibility of corps. As a result, in order that propelling and brake forces on the axes of electric locomotive corresponded to distribution of weight on rails on wheelpairs, it is necessary to support identical correlation of weight and efforts on the axes of electric locomotive. The design of transients was conducted in the system of group electric hauling drive of mine electric locomotive in the mode of starting and braking. A design is executed for the engine of direct-current with successive connection of poles and hauling asynchronous engine. The charts of transients in the system of group electric hauling drive of mine electric locomotive in the mode of starting and braking showed absence of processes of skidding and slipping at application of the offered principle for the control system.

Manufacturing Process And Tonase Calculation On Bumper Rear Axle Bracket Rh

Rear Axle Bumper Bracket is a non-frame part of the car that functions to connect the bumper itself to the rear axle and to withstand collisions and also reduce collisions. Rear Axle Bumper Brackets are commonly used for vehicle components. This writing aims to determine the process of making the Rear Axle RH Bumper Bracket and the total force in the blanking (cutting) process and also in the bending (bending) process of the RH Rear Axle Bumper Bracket Lower Part. Bumper Rear Axle Bracket RH is made by going through a material formation process by cutting blanking and bending, followed by a welding process using spot welding to the painting stage using a powder coating method of dipping. Based on the results of calculations using SPH 440 OD material for the main material for making Bracket Bumper Rear Axle RH Lower Part, it was found that the amount of tonnage that occurred in the blanking process (cutting) was 84.09 Tons with an added reserve force of 8.41 Tons with a value of 84.09 Tons. safety factor of 1.3 which has been standardized on the use of static loads so as to produce the capacity of the press machine needed for the blanking process (cutting) which is 120.25 tons with the actual press machine used of 110 tons. For the bending process, it can be done with a total bending force of 27.19 tons with the added pad force in the bending process of 6.8 tons so that the total force on the Press machine needed for the bending process is 34 tons with the actual press machine. used is 110 tons.

Numerical Study of Powder Flow Nozzle for Laser-Assisted Metal Deposition

Metal additive manufacturing has received much attention in the past few decades, and it offers a variety of technologies for three-dimensional object production. One of such technologies, allowing large-sized object production, is laser-assisted metal deposition, the limits of which are determined by the capabilities of the positioning system. The already-existing nozzles have either a relatively low build rate or a poor resolution. The goal of this work is to develop a new nozzle with a centered particle beam at high velocity for the laser-assisted metal additive manufacturing technologies. Scientific challenges are addressed with regards to the fluid dynamics, the particle-substrate contact, and tracking of the thermodynamic state during contact. In this paper, two nozzles based on the de Laval geometry with Witoszynski and Bicubic curves of convergence zone were designed; the results showed that the average flow velocity in a Bicubic outlet curve nozzle is around 615 m/s and in Witoszynski this is 435 m/s. Investigation of particle beam formation for the Bicubic curve geometry revealed that small particles have the highest velocity and the lowest total force at the nozzle outlet. Fine particles have a shorter response time, and therefore, a smaller dispersion area. The elasto-plastic particle-surface contact showed that particles of diameter limited up to 3 μm are able to reach experimentally obtained critical velocity without additional heating. For particle sizes above 10 μm, additional heating is needed for deposition. The maximum coefficient of restitution (COR) is achieved with a particle size of 30 μm; smaller particles are characterized by the values of COR, which are lower due to a relatively high velocity. Particles larger than 30 μm are scalable, characterized by a small change in velocity and a rise in temperature as their mass increases.

The Immediate Effect of Static Hamstring Stretching on Dynamic Balance and Gait Biomechanical Variables in Athletes With Hamstring Tightness: A Preliminary Study

Introduction: Flexibility is an essential component of muscle function, and insufficient muscle flexibility may lead to muscle injuries. Decreased hamstring flexibility is one of the frequently reported risk factors for a hamstring strain and diminished athletic performance. Stretching is a commonly used intervention for increasing muscle length. There is a lack of evidence concerning the possible effects of hamstring stretching in balance and gait biomechanics. So, this study was designed to investigate the potential effects of static hamstring stretching on the range of motion (ROM), dynamic balance, and biomechanical variables of gait in athletes with hamstring tightness. Materials and Methods: This study is a single-group, pretest-posttest clinical trial performed on semi-professional female athletes. Twelve female athletes aged 20 to 35 years with bilateral hamstring tightness received a single session of unilateral static hamstring stretching on their randomly selected side. All subjects were assessed for straight leg raise, popliteal angle (using standard goniometry), perceived hamstring tightness (using a visual analog scale). They completed single-leg standing and 15-m walking and running tasks before and immediately after the intervention. The biomechanical parameters, including gait-line length, swing duration, and stance duration in walking tasks, maximum total force and mean total force in running task, and center of pressure (COP) displacement and standard deviation during balance task were measured using OpenGo sensor insole system. The pre-post values were compared using the paired sample t-test, and the level of significance was 0.05. Results: The values for straight leg raise and popliteal angle significantly increased (P<0.05) compared with the baseline, while perceived tightness significantly decreased following stretching (P<0.001). The amplitude (P₌0.006) and standard deviation (P₌0.016) of COP displacement in the mediolateral direction during the single leg stance balance task were significantly decreased after the intervention. Stance duration in slow walking (P₌0.004), as well as stance duration (P₌0.012) and swing duration (P<0.001) in fast walking, were significantly decreased (P<0.05) after stretching. No change was observed in gait biomechanical variables during the running test (P>0.05). Conclusion: The results of this study indicate that static hamstring stretching can be a promising intervention not just for increasing hamstring flexibility but also for improving balance ability.

Dynamics of special physical training of qualified MMA fighters during the preparatory period of the macrocycle when performing shock equipment

Purpose: to determine the influence of the experimental training program for qualified mixed martial arts fighters of 18-19 years old on their special physical fitness when performing shock actions. Material and methods. The study involved seven athletes 18-19 years old (all athletes - KMSU) department of mixed martial arts ODYUSSH «Dinamovets» in Zhitomir. A training program for qualified junior mixed martial arts fighters was developed using interval and interval-circular training methods with a wide range of general, special and competitive training means. The training program is designed for 15 weeks (may 17 - august 27, 2021) in the preparatory period of the macrocycle, therefore its predominant focus was towards physical fitness. Research methods: analysis of scientific theoretical sources, conversations with specialists, pedagogical observations, pedagogical testing, methods of mathematical statistics. Results: the dynamics of special physical readiness of qualified fighters was investigated, under the influence of an experimental training program, when performing percussion technique. The study of the dynamics of special physical readiness when performing a series of punches with hands showed significant positive shifts in the total force of punches with hands during the execution of an 8-second series (t=3,02; p˂0.05) and a 40-second series of punches (t=7,69; p˂0,001). The result of the average force of strikes (t=2,21; p˂0,05) in a 40-second series of strikes also noticeably improved. The study of the dynamics of special physical readiness when performing a series of strikes with the dominant leg revealed positive changes in the total force of strikes in the 8-second (t=3,33; p˂0,01) and 40-second (t=5,39; p˂0,001) tests. The high-speed component of the striking technique did not undergo significant positive changes, although there is a tendency towards positive dynamics (p>0,05). Conclusions. It was determined that the introduction of an experimental training program into the educational and training process of 18-19 year old mixed martial arts fighters made it possible to improve the special physical fitness of the fighters when performing specific striking techniques. In five studied indicators, a significant positive trend was obtained, confirmed by mathematical calculations. Significant positive changes in the total strength in the series of punches with the hands and the dominant leg were determined both in the 8-second and in the 40-second tests (p˂0,05 - p˂0,001). We also found a significant positive dynamics in the average force of punches in the 40-second test (p˂0,05). Keywords: mixed martial arts, qualified fighters, special physical training; interval training method; Interval-circular training method; training aids.

Comparative analysis of the hydrodynamic performance of pre-swirl stator pump-jet propulsor under different rotational speeds

The pump-jet propulsor(PJP) performances under various rotational speeds (20~50 r/s) are analyzed for further studying the influence of the Reynolds number (Re) on the hydrodynamics of PJP, before this, the calculation model is verified by using the experiment data, it proves the present numerical method is proper to make a further study. The results indicate both the hydrodynamic coefficients of PJP and PJP components and the contours with dimensionless variables are present high similarity, yet the Re has the slight effect on the components performance, among which, the force coefficient of rotor is the least affected, with a relative error no more than 1%. Followed is the force coefficient of rotor stator, the maximum error is 2.1%, since the force of duct and stator is so low that has the slight effect on PJP, the total force error is less than 2%. However, the torque coefficient error is bigger with a value of about 3%. Besides, it is found that all hydrodynamic coefficients vary monotonically with rotating speed, the higher Re caused by increasing the rotational speed will contribute to enhance the work ability of rotor, thus cause a lower pressure at vortex core, and change the trajectory of TLV.

Geomagnetic inverse modeling to estimate the volume of magnetization in areas with topographic variations

A three-dimensional geomagnetic modeling is proposed to obtain information about a magnetization over topographic area from magnetic total force from land data survey. The model is divided into three-dimensional mesh grid of rectangular prisms that cover a finite depth below topographic elevation. The model parameter is assigned to each prism describing magnetization. A set of linear equations was formulated in terms of volume magnetization for each prism. The inverse calculation is obtained using the solution of over-determined problems. In this inverse calculation over three-dimensional mesh grid, the weighted matrix will be used to determine distribution of volume magnetization in the subsurface and keep the zero value of volume magnetization above the surface. A computer program has been tested with artificial topographic data and applied to digital elevation model of Bandung. The result of the inversion shows the comparison between synthetic model and inverse model to provide several analysis of algorithm performance. The high magnetization value can be characterize using inverse model up to 77% of volume area with average success recovery of model parameter value up to 56%.

Dynamic warpage simulation of molded PCB under reflow process

Purpose This study aims to simulate molded printed circuit board (PCB) warpage behavior under reflow temperature distribution. Simulation models are used to estimate dynamic warpage behavior for different form factor sizes. Design/methodology/approach This study analyzes warpage during the reflow process. The shadow moiré experiment methodology is used to collect data on the dynamic warpage performance of a model with a form factor of 10mm × 10mm × 1mm. The temperature profile with heating from 25°C to 300°C at intervals of 50°C is used, and the sample is made to undergo a cooling process until it reaches the room temperature. Subsequently, ANSYS static structural simulation is performed on similar form factor models to ascertain the accuracy of the simulation results. Findings Results show that the deformation and total force induced by coefficient of thermal expansion (CTE) mismatch are examined based on the warpage performance of models with different sizes, that is, 45mm × 45mm × 1mm and 45mm × 15mm × 1mm. Compared with the experimental data, the simulated modeling accuracy yields a less than 5% deviation in the dynamic warpage prediction at a reflow temperature of 300°C. Results also reveal that the larger the model, the larger the warpage changes under the reflow temperature. Research limitations/implications The simulated warpage is limited to the temperature and force induced by CTE mismatch between two materials. The form factor of the ball-grid array model is limited to only three different sizes. The model is assumed to be steady, isothermal and static. The simulation adopts homogenous materials, as it cannot accurately model nonhomogeneous multilayered composite materials. Practical implications This study can provide engineers and researchers with a profound understanding of molded PCB warpage, minimal resource utilization and the improved product development process. Social implications The accurate prediction of molded PCB warpage can enable efficient product development and reduce resources and production time, thereby creating a sustainable environment. Originality/value The literature review points out that warpage in various types of PCBs was successfully examined, and that considerable efforts were exerted to investigate warpage reduction in PCB modules. However, PCB warpage studies are limited to bare PCBs. To the best of the authors’ knowledge, the examination of warpage in a molded PCB designed with a molded compound cover, as depicted in Figure 3, is yet to be conducted. A molded compound provides strong lattice support for PCBs to prevent deformation during the reflow process, which is a topic of considerable interest and should be explored.