Circular Recess Research Articles

Fluoroscopic Categorization of Cementless Acetabular Component Positioning.

The purpose of this study was to evaluate a fluoroscopic method of angle of lateral opening (ALO) categorization based on identification of the visible portion of a pre-existing, circular recess within the metal shell of the BioMedtrix BFX acetabular component, which projects as an ellipse at clinically relevant ALO values. Our hypothesis was that there will be an association between the actual ALO and the categorization of ALO based on identification of the visible portion of the elliptical recess on a lateral fluoroscopic image at clinically relevant values. A custom plexiglass jig was fitted with a two-axis inclinometer and a 24 mm BFX acetabular component attached to its tabletop. Fluoroscopic reference images were obtained with the cup positioned at an ALO of 35, 45 and 55 degrees with a fixed 10 degrees of retroversion. Thirty study fluoroscopic images (10 images at each ALO) were obtained based on randomization at an ALO of 35, 45 and 55 degrees (±0.5 degrees) with 10 degrees of retroversion. The order of the study images was randomized, and a single, blinded observer categorized the 30 study images as representing an ALO of 35, 45 or 55 degrees by comparison to the reference images. Analysis showed perfect (30/30) agreement with a weighted kappa coefficient of 1 (95% confidence interval: -0.717 to 1). The results demonstrate that accurate categorization of ALO can be achieved using this fluoroscopic method. This method may prove to be a simple but effective method of estimating intraoperative ALO.

Influence of magnetorheological lubricant behavior on the performance of annular recessed orifice compensated non-textured/textured thrust pad bearing

Fluid film bearings operated with smart lubricants have been successfully used to enhance the lubricating performance. This article proposes a computational model to analyze the influence of magnetorheological lubricant on the performance of an annular recessed hybrid thrust bearing system. The governing modified Reynolds equation for circular thrust pad orifice compensated bearing is solved by finite element method. Further, for simulating the flow behavior of magnetorheological lubricant, a constitutive relation for the Bingham model Dave equation, has been used. The numerical results reveal that using magnetorheological lubricant improves the loading carrying capacity and damping coefficient of both annular and circular recess hybrid thrust bearings. Additionally, bearing lubricated with magnetorheological lubricant requires a lesser quantity of flow and hence less pumping power.

A Technology of Hydrocarbon Fluid Production Intensification by Productive Stratum Drainage Zone Reaming

The paper proposes a new technology for fluid production intensification, in particular hydrocarbons, which is implemented via significant increasing of the local wellbore diameter in the interval, where the productive stratum is present. The proposed technology improves the well productivity by increasing the filtration surface area and opening new channels for filtering fluids into the well. The innovative, technical idea is to drill large diameter circular recesses in planes perpendicular to the well axis. After that, the rock mass located between the circular recesses are destroyed by applying static or dynamic axial loads. The required value of the axial force is provided by the weight of the standard drilling tool. As a result of the study, the analytical relations to specify the admissible radius of circular recesses and admissible thickness of rock mass between two adjacent circular recesses from the condition of safe operation are obtained. The numerical analysis carried out for typical reservoir rocks substantiated the possibility of well diameter local reaming twenty times. A special tool for circular recess drilling is developed and the principle of its operation is described. The advantage of the proposed approaches is the low energy consumption for well diameter reaming. Our technology will have special economic expediency for the intensification of production from hydrodynamically imperfect wells and under the condition of fluid filtration according to the expressed nonlinear law.

Знахідки в басейні р. Тясмину мідних монет Ольвії з Деметрою та «істрійським» варіантом міської емблеми

У районі басейну р. Тясмину, як і в цілому на території Дніпровського Правобережного Лісостепу, зустрічаються знахідки давньогрецьких монет ІV ст. до н.е., у тому числі й досить рідкісні. Серед корпусу знахідок давньогрецьких монет на території басейну р. Тясмин особливе місце належить монетам Ольвії. У статті розглядаються знахідки в басейні р. Тясмину мідних монет Ольвії з Деметрою та «істрійським» варіантом міської емблеми. Номінал цього типу монет дослідники досить часто визначають як «обол». В історіографії містяться відомості про імена монетних магістратів відповідальних за випуск цього типу монет. Кількість цих імен у різних дослідників коливається від 14 до 20. Проте, ймовірно, ця кількість імен має бути більшою. Проаналізовані у статті ольвійські оболи з Деметрою та «істрійським» варіантом міської емблеми, знайдені далеко за межами ольвійської хори, вперше введені до наукового обігу монети даного типу, що значно розширює раніше відому топографію знахідок монет цього типу. Знахідки в басейні р. Тясмин на території Олександрівського району Кіровоградської та Чигиринського району Черкаської області монет, карбованих у IV ст. до н.е. у грецькій колонії Ольвії, свідчать про існування зв’язків населення басейну р. Тясмин з мешканцями грецьких міст Північно-Західного Причорномор’я у вказаний хронологічний період. Знахідки давньогрецьких монет на території Дніпровського Правобережного Лісостепу, у тому числі й районі басейну Тясмину, спростовують побутуючу в історіографії думку про те, що мешканці Середнього Подніпров’я мали виключно товарообмінні операції з грецькими колоніями в Північному Причорномор’ї, а бронзові монети, які випадково і в незначних обсягах потрапляли до даного регіону, могли використовуватися як сировина для виготовлення бронзових предметів.

Forces in the Lock-Off Device During the Rolling of the Brake Pulley Roller Over the Brake Ramp in the Built Automatic Parking House

The paper describes the design of the device, which allows for the scanning and recording of force sizes impacting in horizontal and vertical directions during the rolling of the pulley, which is part of the brake of the lock-off device of the pallet truck, over the top surface of the brake ramp. The paper also presents the results of two experimental measurement procedures. The first measurements taken to obtain the values of the applied resistive forces when the cylindrical part of the pulley was inserted into the brake body were carried out without an installed cylindrical coil spring. The aim of the second measurement was to determine the forces acting on the brake body when the brake pulley holder resists the insertion into the brake body due to the rigidity of two types of compression cylindrical coil springs, type R16-102 and V16-102. These measurements were carried out in order to verify the theoretically calculated values of the acting forces. In the chapter “Pallet brake design” there is a suggestion and recommendation of the lock-off device manufacturer, which is used in the automatic parking system of variants “KOMA TOWER” and “KOMA MULTI TOWER”, to use a sensor to eliminate inaccuracies of parking location in a parking house using this APS option. The forces acting on the brake body, shown in the tables and graphs in this paper, are forces that occur when the brake pulley rolls over the upper surface of the brake ramp until the pulley engages in a circular recess in the brake ramp.

A new holder/container with a porous cover for atomic layer deposition on particles, with transport analysis and detailed characterization of the resulting materials

Atomic layer deposition (ALD) is widely used in the semiconductor and materials industries for depositing thin films. Here, we describe a holder/container for performing ALD on particles that does not require agitation. This device contains a broad, shallow, circular recess that holds the particles. Two different frits and combinations of stacked meshes were explored as a cover to this holder to restrict the movement of the particles while still allowing good conductance of the ALD reagent gases. A mathematical discussion of the diffusion through the frits and stacked meshes is presented. As confirmed by spectroscopic ellipsometry (SE) on planar witness silicon shards, consistent, high‐quality film growth took place inside and outside the holder. The performance of the holder was demonstrated with ~5‐μm zirconia particles that were coated with alumina from trimethylaluminum (TMA) and water, and with zinc oxide from diethylzinc (DEZ) and water. Deposition on different amounts of particles was investigated (50, 100, 200, and 500 mg). Parasitic chemical vapor deposition (CVD) appeared to be present when a greater number of particles or meshes were used. ALD coating on particles was also confirmed by X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and energy‐dispersive X‐ray spectroscopy (EDS).

Influence of recess shape on comprehensive lubrication performance of high speed and heavy load hydrostatic thrust bearing

PurposeThis paper aims to describe a theoretical and experimental research concerning influence of recess shape on comprehensive lubrication performance of high speed and heavy load hydrostatic thrust bearing with a constant flow.Design/methodology/approachThe lubrication performance of a hydrostatic thrust bearing with different recess shape under the working conditions of high speed and heavy load has been simulated by using computational fluid dynamics and finite volume method.FindingsIt is found that the comprehensive lubrication performance of a hydrostatic thrust bearing with circular recess is optimal. The results demonstrate that recess shape has a great influence on the lubrication performance of the hydrostatic thrust bearing.Originality/valueThe simulation results indicate that to get an improved performance from a hydrostatic thrust bearing with constant flow, a proper selection of the recess shape is essential.

Hydrostatic Bearing Design Selection for Automotive Application Using Pugh Controlled Convergence Method

This paper evaluates the design selection of a hydrostatic bearing pad for automotive application. The purpose of hydrostatic bearing is to eliminate high frequency vibration from gear mesh-frequency, example from heavy truck. Pugh controlled convergence method was used to obtain the optimum design shape for selection. The setting up parameter criteria verses the concept pad shape between applications of hydrostatic journal and hydrostatic thrust bearings were varied. Comparison of design engineering criteria was made with number of leading concepts in hydrostatic bearing for ultimate qualitative optimization, and the parameter design criteria was customized for automotive heavy truck vehicle. Fourteen (14) selection considerations were used as, manufacturing ease, safety of the design, cost development, accuracy in output, reliability in life span, simplicity in degree of design, load capacity, stiffness, damping, suppress temperature rise, pumping power, mounting space for fitting, oil circulation without leakage and finally displacement of the controlled plunger. From this convergence method,‘Circular recess pocket plunger’ with spring loaded (CRPP) conceptually selected. It was model from qualitative optimization by combining ‘squeeze film damper’ (SFD) of a journal bearing without journal rotation and Cooper's squeeze film coil spring test apparatus.

Plastic Collapse Behaviors of Tubulars with Recess Patterns—Application in Hollow Carrier Perforating Guns

The collapse strength of tubulars with recess patterns machined into their walls is an important topic for oil field downhole tools, especially in hollow carrier perforating gun systems. This paper presents a study of the plastic collapse behavior of thick-walled tubulars (those with an outside diameter to thickness ratio of approximately ten) having different patterns of circular recesses (blind holes partially machined into the tubing wall) that are subjected to external pressure. An empirical relationship between the reduction in collapse strength and the periodic distribution of recesses was constructed to account for the weakening effects of recess diameter, recess depth, axial spacing, angular phasing, etc. This strength reduction factor was introduced into the Tamano formula to predict collapse strength of recessed tubulars. Applicability of this empirical formula was validated with the aid of nonlinear, postbuckling finite element analyses (FEA). The strength reduction factor in combination with the Tamano formula provides a simple way of parametrically predicting the collapse strength of tubulars having circular recess patterns.

The influence of recess depth and crystallographic orientation of seed sides on homoepitaxial growth of CVD single crystal diamonds

Microwave plasma chemical vapor deposition (MPCVD) has gained increasing attention as a feasible and effective way to produce large, high-quality, single-crystal diamonds. However, the growth of polycrystalline diamond on the periphery of the seed crystal and the cracking generated by the internal stress during the growing process lead to significant decline of the quality and integrity of the CVD diamond, thus increasing the difficulty of synthesizing large diamond layers. Although optimized growth parameters and refined substrate holders have been employed by some researchers to improve the periphery quality of CVD diamond layers, more research needs to be done in this area. In this study, we used a specially designed substrate holder with a circular recess, in which the seed crystal was placed. By designing substrate holders with different recess depths and a seed crystal with different side-surface crystallographic orientations, we aimed to determine the influence of the recess depths and the crystallographic orientation of seed sides on the growth quality according to polarizing microscope, laser Raman spectroscopy, UV fluorescence imaging, and photoluminescence (PL) mapping measurements. The results demonstrate that as the recess depth increases, the amount of polycrystalline diamonds and the internal stress on the periphery are controlled effectively. The crystalline quality is improved, and the growth rate is decreased. In addition, compared to the periphery with {100} seed sides, the periphery with {110} seed sides displays better crystalline quality, lower internal stress, and fewer polycrystalline diamonds after growth, which is probably due to the intrinsic nature of the growth steps propagating on the {100} diamond surface and the effect of nitrogen atoms on the growing process in the diamond lattice.

Influence of Oil Seal Edge on Lubrication Characteristics of Circular Recess Fluid Film Bearing

Influence of Oil Seal Edge on Lubrication Characteristics of Circular Recess Fluid Film Bearing

Velocity Characteristic on Oil Film Thickness of Multi-Pad Hydrostatic Thrust Bearing with Circular Recess

Velocity Characteristic on Oil Film Thickness of Multi-Pad Hydrostatic Thrust Bearing with Circular Recess

Numerical and Experimental Study of the Flow Field Structure Evolution in the Circular Recess of Oil Cavity

The laminar radial flow in the oil cavity of heavy-duty computer numerical control (CNC) machines is very complicated and has not been fully explored. Navier-Stokes equations have been applied through the whole flow region using finite volume approach to explore this complicated flow phenomenon, including the influences of the clearance height (h), inlet nozzle Reynolds number (Re), and geometrical aspect ratio (e) on flow behaviors. A fluid dynamic experiment has been conducted to study the flow structure by using particle image velocimetry (PIV). Numerical simulation results have been compared with the experimental results, finding a good agreement with the studied cases. The results suggest that there are complex vortices in the oil cavity. Flow field structure of the oil cavity largely depends onh, Re, ande. Re andehave a great influence on the size and amount of vortices, andhhas slight effects on the size of the vortices. The lengths of primary, secondary, and tertiary isolated vortices have a linear relationship withh. The lengths of the primary and secondary isolated vortices increase linearly with ascendingeaseis small. But when Re andeare large enough, the size of the three vortices decreases.

Performance of hydrostatic circular thrust pad bearing operating with Rabinowitsch fluid model

Polymer-based additives such as poly isobutylene are blended with lubricating oil to enhance the lubricating performance of the base oil. The Rabinowitsch fluid model effectively describes the influence of polymer additives on the lubricating performance of a non-Newtonian (pseudoplastic) lubricant. This article deals with the analysis of a capillary compensated hydrostatic circular thrust pad bearing using Rabinowitsch fluid model. For a circular recess hydrostatic thrust bearing operating with pseudoplastic lubricant, the closed form expressions for load-carrying capacity, lubricant flow rate, fluid film stiffness coefficient and damping coefficient have been obtained using a small perturbation method. The close form solutions for different performance characteristic parameters have been compared with the results obtained from finite element method formulation. The numerically simulated results indicate that pseudoplastic parameter significantly affects the parameters of the bearing performance characteristics such as pocket pressure, lubricant flow rate, fluid film stiffness coefficient and damping coefficient. The value of the fluid film stiffness coefficient gets substantially increased with the pseudoplastic parameter whereas the value of damping coefficient gets reduced. The analytical results presented in this study can be used to obtain an optimum performance of a hydrostatic circular thrust pad bearing.

Three-dimensional pressure- and shear-driven flow phenomena in a circular recess of a hydrostatic rotary table

The three-dimensional pressure- and shear-driven flow phenomena in a circular recess of hydrostatic rotary table in heavy-duty computer numerical control machines is very complicated and has not been fully explored. Navier–Stokes equations have been applied through the whole flow region using a finite volume approach to explore this complicated flow phenomena, including the influences of feeding Reynolds number ( Rei), sliding Reynolds number ( Res) and the recess geometry on flow behaviors. A test rig based on a particle image velocimetry was built to compare experimental and numerical results, finding a good agreement for stationary cases. The results show that the flow patterns in the recess are very complex and four three-dimensional vortices exist at Rei = 448 and Res = 74.6. Four flow states are defined according to the structure of the vortices. Different sectional profiles of the streamlines and velocity vector fields are examined to reveal the mechanism of pressure- and shear-driven flow interactions. The results of influences of recess geometry on flow states and pressure patterns are intended to contribute to represent a database in view of the hydrostatic rotary table theoretical modeling.

Dynamic Optimization of Hydrostatic Supported Worktable System with Circular Oil Recess

In this paper, optimal parameters in hydrostatic supported worktable system with circular oil recess are calculated. The optimal model is established in which the objective is to make natural frequency deviate from speeds of the rotary work axis, and the design variables are recess number, initial oil film thickness and recess radius. As the design variable vector includes both discrete and continuous components, two-phase optimization strategy is developed. Furthermore Fibonacci method is applied to deal with the problem of discrete variable, and response surface methodology is used to form an explicit expression between the objective expression and continuous variables. Then the optimal model is solved by gradient projection method and simplex method. As a result, numerical calculation of dynamic optimization with hydrostatic worktable system with circular recess shows that two-strategy optimization algorithm is stable and effectively.

Recess Depth Optimization for Rotating, Annular, and Circular Recess Hydrostatic Thrust Bearings

Inertial effects due to the centripetal forces may become dominant at high rotational speeds in hydrostatic thrust bearings. Although this influence has been recognized in literature, bearings are commonly optimized with respect to the minimum friction, and the dissipation function has not been taken into account in the optimization procedures. It is observed that the secondary flow caused by the inertia term gives a large contribution to the dissipation for applications with a high rotational speed. In this study, the minimum dissipation for annular and circular recess thrust bearings operating at a certain rotational speed is determined by finding the optimum film thickness in the recess. An example is given for annular recess thrust bearings.

On an approach to numerical solution of stress-strain state problems for nonthin plates and shells

Numerical solution of elastic equilibrium problems for nonthin plates and shells of constant and variable thickness is based on using a curvilinear-mesh method in combination with the Vekua method — reduction of three-dimensional elastic equations to a recurrent sequence of boundary problems in a two-dimensional region. Coefficients of the first and second quadratic forms for a conditional mediane surface are calculated by means of a metric of boundary faces without any derivatives with respect to their local bases. Specific examples of numerical solution of the test problems for a thick plate bending case, for which the exact and approximate solutions can be also found by other methods, have proven the proposed numerical approach to be efficient (in terms of a rapid convergence and accuracy). A numerical solution has been obtained for a problem of bending for a nonthin plate of constant and variable thickness made of an orthotropic material and for a shell with a circular recess under axial compression.

Turbulent flow in a cylindrical circular-recess channel

Modeling of a turbulent flow in a cylindrical solid propellant charge channel having a circular recess (compensator) has been performed. Different variants of the compensator position and connection to the channel are discussed. The influence of the geometric and consumption factors on the formation of distributions of the gas-dynamic parameters and characteristics of turbulence in the working region has been investigated.

(1-24) Effect of Recessed-Wall on an Impingement Diesel Spray((FS-2)Fuel Sprays 2-Diesel sprays)

Behavior of spray impinged on a recessed-wall was experimentally investigated as a new concept of impingement diesel spray. The spray injected through a diesel nozzle impinged vertically on the center of the circular recess. Spray height as well as spray path penetration was measured at various timings on high speed photographs of the spray, which was injected by a single shot injection system into a high pressure chamber. The spray after impinging on the recessed-wall was reflected from the recess with rolling up motion more than the impingement spray on a flat wall (upper photographs in Fig. 1). However, in a case that the spray width at the wall location was wider than the recess diameter, the spray after impingement expanded along the wall (lower photographs in Fig. 1). Figure 2 shows parameters of spray impinging on a recessed-wall. The spray behavior on the recessed wall was controlled more by the width-to-diameter ratio Ws/Dr than by the recess diameter (Fig. 3). Also, for the purpose of increasing the spray height, it is necessary that the value of Ws/Dr should be around 0.5 (Fig. 4). At this ratio, the rolling-up motion was observed clearly and strongly on the recessed-wall.