LABOR AND FINANCIAL COSTS IN TREATMENT OF DENTOALVEOLAR ANOMALIES IN THE PERIOD OF THE MIXED OCCLUSION

The aim of the present study is to analyze the complexity and cost of modern methods of orthodontic treatment of children during the period of replacement bite. The study of the duration and frequency of visits to the doctor the orthodontist with the use of technology 2x4, removable plates with artificial teeth, ring spacer, plate from the front Nakonechny pad and plate valve for the language of the Twin-block appliance, mask dilara combined with the expanding apparatus, plate screw, machine screw hyrax expansion. Based on the complexity of the calculated salary orthodontist doctor, medical and other personnel. The cost of consumables at the clinical and dental stages was determined by taking into account the purchase prices and the cost of a specific manipulation by weighing or measuring. Calculated the expenditure on maintenance of workplaces of the doctor and dental technician in the calculations of the required funding early orthodontic treatment used more information about the structure and prevalence of orthodontic pathology in children in the period of the mixed occlusion. It was found that the complexity of modern orthodontic treatment during the period of replacement bite varies from 5.55 hours (spacer with a ring in case of premature loss of a temporary tooth) to 10.73 hours in the treatment of distal bite with the twin-block device. The cost of orthodontic treatment during the period of replacement bite ranges from 12.6 thousand rubles (spacer with a ring in case of premature loss of a temporary tooth) to 33.4 thousand rubles in the treatment of mesial bite using a dilyar mask in combination with an expanding apparatus. Taking into account the prevalence of dentoalveolar anomalies in children during the period of replacement bite, the necessary financial costs for orthodontic treatment per one examined child and per child with a dentoalveolar anomaly reach 30 and 40 thousand rubles, respectively.

The Erosion-Corrosion Behaviors of the Full-Scale PFF78-70 Flat Valve and P110SS Tubing

In the present work, a self-built device called “full scale tubular goods erosion-corrosion test system” was used to test the P110SS tubing with a total length of 10 m and a full scale PFF78-70 flat valve to study their erosion-corrosion behaviors in the acceleration simulation operating condition of a well in Sichuang oil field of China. The erosion-corrosion performance of the specimen was investigated by KH-7700 digital microscope, scanning electron microscopy (SEM), X-ray power diffraction (XRD) and energy-dispersive spectroscopy (EDS). The results indicated that the P110SS tubing suffered catastrophic erosion-corrosion; the maximum pitting corrosion rate of the P110SS in the gas phase fluid was 5.29mm/a; while that in the liquid phase fluid was 11.13mm/a; A double-layer corrosion products scale, inner FeCO3 layer and outer mixture layer mainly dominated by FeO, Fe3O4, Fe2O3 and FeO(OH), formed on the P110SS tubing. Erosion-corrosion only occurred in the stress concentration area of the valve plate hole of the PFF78-70 plate valve, and the size of the corrosion pits is about 0.5mm.

Modeling of a Fast Plate Type Hydraulic Check Valve

Check valve dynamics plays an important role in many fluid systems, such as in compressors, hydraulic pumps, and hydraulic switching converters. Plate type check valves are a frequently employed valve type in dynamically challenging cases. Despite the relevancy of plate valve dynamics, only few exhaustive works can be found in the literature, focusing on the behavior of hydraulic check valves for high-frequency applications. This paper presents an in-depth characterization of a plate valve designed as rectifier of a high-frequency oscillation pump working at 300 Hz. The aim is to identify a sufficiently simple mathematical model, which permits to optimize the design of the valve for the considered application. The paper analyses the different phenomena contributing to the dynamics of such a valve and presents the results of simulation and experimental activity. The results show how small details in the design and manufacturing of those valves (namely, the contact surfaces) have important consequences on the dynamics of the pump system. In general, a good agreement between model and reality is achieved.

Forces Analysis on a Spherical Shaped Delivery Valve of Hydram Pump

Hydram pump has been found more than two centuries ago, and has been widely developed and operated to this day. However, constraints complaints by the people are easily damaged on its rubber of waste valve and delivery valve of the hydram pump. In addition, the reliability of the plate valve models is also awfully where its rubber of the valve is quickly worn or damaged. It has been reducing the interest of the community in utilizing hydram pumps. Moreover, there is no yet a comprehensive procedure in planning and making dimensions of hydram pump. Then, design of a spherical shaped delivery valve model on the hydram pump has been made ​​and tested. Considering that hydram pump is also called impulse pump which work due to the effects of water hammer, therefore, it need to know the forces that take place in the hydram pump. Then, from these forces can be calculated dimensions of hydram pump and its performance can be predicted. From the results of the study shows that dimensions and performance of the hydram pump is very close to the results of assessment that has been done. Finally, a procedure in planning a hydram pump has been recommended.

On the Dynamic Behavior of Check Valves for High Frequency Oscillation Pumps

Fast check valves play a key role in digital hydraulics and high frequency oscillation pumps (HFOP); in these applications check valves with very short response times in the order of hundreds of microseconds are required. This paper presents a study on the dynamics of two different types of check valves, namely a ball valve available from the market and a plate valve designed specifically for a novel HFOP. A high frequency pumping cycle using such valves has been simulated mathematically in Matlab/Simulink for different working conditions. The same was reproduced physically by means of a test rig specifically designed for testing high frequency valve dynamics. The comparison between simulated and experimental results shows the influence of valve design (e.g. geometry of moving element) as well as fluid propagation effects on the dynamics of the process. The volumetric efficiency of the pumping cycle resulting from the collected data is a major input for the design of the valve for the specific HFOP application.

Modeling for a High-Bandwidth High-Flow Valve Design Based on Ho¨rbiger Plate Operation

In order to expand the operational capabilities of hydraulically actuated systems the development of new valves to allow of enhanced flow rates and bandwidth performance is required. Previously, the technical challenge in developing such valves was the need for large spool strokes to achieve the desired flow rates. However, this would then hinder the dynamic response of the valve. To increase flow without reducing dynamic performance it is proposed that the use of multiple metering edges is appropriate. This is achievable using the Ho¨rbiger plate valve principle and direct connection to a piezoelectric actuator. This paper examines the design criteria associated with such a valve. Simulations undertaken as part of its construction and design show that improved flow rates can be achieved. Results from these simulations are then included in orifice equations to further predict flow as a function of plate separation. Finally a simulation was undertaken to determine the total forces acting on the valve, and the forces on the piezoactuator were found to be compressive under normal conditions, which should lead to predictable and stable operation.

SEWHAPM: Development of a Water Hydraulic Axial Piston Motor for Underwater Tool Systems

Water hydraulic motor (WHM) is an important transmission component in a water hydraulic system. Because of different physicochemical properties of raw water when compared with mineral oil, the design for the WHM would be different from that for a mineral oil one. A static equilibrium-type water hydraulic axial piston motor (SEWHAPM), which is equipped with a global-moment-balanced plate valve and a hydrostatic slipper bearing with a concentric gap damper, is developed in this research. The mechanism of the global-moment-balanced plate valve is analysed to eliminate the irregular wear of the plate valve. Next, the relevant design guideline is constructed. A mathematical model of the hydrostatic slipper bearing is established, and the performance characteristics of the bearing are discussed. The theoretical analyses indicate that the load-carrying capacity of this hydrostatic slipper bearing is not correlated with system pressure, water viscosity, temperature, or rotor speed, and that the lubrication film thickness of the bearing possesses high rigidity. The fundamental principle for designing the hydrostatic slipper bearing is also derived. On the basis of a material-screening experiment, a SEWHAPM is fabricated and tested on a water hydraulic-component-performance test stand. The experimental results show that developed SEWHAPM is feasible, with its volumetric, mechanical, and total efficiencies being ∼86, 80, and 70 per cent, respectively, under a pressure of 10 MPa. The maximal output torque can reach ∼19.5Nm; the maximal speed can reach 3000 r/min. As a result of the aforementioned development, the SEWHAPM has been successfully used in an underwater tool system since 2002, and its performance has been tested, demonstrating that the developed equipment can meet the regulated requirements for its practical applications.