High Displacement Research Articles

The process of superdeep penetration of high-speed metallic particles in solid body

An explanation of the effects arising at the collision of a stream of metal particles with a size of 10–100 microns, moving at a speed of 1–3 km/s, with a solid target is proposed. It is assumed that at the moment of impact on the target, the particle loses some electrons and for some time, due to the presence of an oxide shell, retains a positive charge. The flow of electrons passing through the target at the moment of impact generates an electromagnetic field pulse. A particle with a charge of about 10–9 C, having penetrated into a solid target, presses on the channel wall with a force of about 500 MPa and moves in it under the action of forces caused by the polarization of the target substance. The combination of high pressure and displacement leads to a significant reduction in the particle-wall friction force. The proposed hypothesis, if confirmed, can help find ways to protect electronic devices of spacecraft from impacts from streams of fast dust particles.

Development and Testing of a Dual-Driven Piezoelectric Microgripper with High Amplification Ratio for Cell Micromanipulation

Cell micromanipulation is an important technique in the field of biomedical engineering. Microgrippers play a crucial role in connecting macroscopic and microscopic objects in micromanipulation systems. However, since the operated biological cells are deformable, vulnerable, and typically distributed in sizes ranging from micrometers to millimeters, it poses a huge challenge to microgripper performance. To solve this problem, this paper develops a dual-driven piezoelectric microgripper with a high displacement amplification ratio, large stroke, and parallel gripping. By adopting modular configuration, three kinds of flexure-based mechanisms, including the lever mechanism, Scott–Russell mechanism, and parallelogram mechanism are connected in series to realize three-stage amplification, which effectively makes up for the shortage of small output displacement of the piezoelectric actuator. At the same time, the use of the parallelogram mechanism also isolates the parasitic rotation movement, and realizes the parallel movement of the gripping jaws. In addition, the kinematics, statics, and dynamics models of the microgripper are established by using the pseudo-rigid body and Lagrange methods, and the key geometric parameters are also optimized. Finite element simulation and experimental tests verify the effectiveness of the developed microgripper. The results show that the developed microgripper allows an amplification ratio of 46.4, a clamping stroke of 2180 μm, and a natural frequency of 203.1 Hz. Based on the developed microgripper, the nondestructive micromanipulation of zebrafish embryos is successfully realized.

Geometric constraint of mechanosensing by modification of hydrogel thickness prevents stiffness-induced differentiation in bone marrow stromal cells.

Extracellular matrix (ECM) stiffness is fundamental in cell division, movement and differentiation. The stiffness that cells sense is determined not only by the elastic modulus of the ECM material but also by ECM geometry and cell density. We hypothesized that these factors would influence cell traction-induced matrix deformations and cellular differentiation in bone marrow stromal cells (BMSCs). To achieve this, we cultivated BMSCs on polyacrylamide hydrogels that varied in elastic modulus and geometry and measured cell spreading, cell-imparted matrix deformations and differentiation. At low cell density BMSCs spread to a greater extent on stiff compared with soft hydrogels, or on thin compared with thick hydrogels. Cell-imparted matrix deformations were greater on soft compared with stiff hydrogels or thick compared with thin hydrogels. There were no significant differences in osteogenic differentiation relative to hydrogel elastic modulus and thickness. However, increased cell density and/or prolonged culture significantly reduced matrix deformations on soft hydrogels to levels similar to those on stiff substrates. This suggests that at high cell densities cell traction-induced matrix displacements are reduced by both neighbouring cells and the constraint imposed by an underlying stiff support. This may explain observations of the lack of difference in osteogenic differentiation as a function of stiffness.

Experimental study on microscopic production characteristics and influencing factors during dynamic imbibition of shale reservoir with online NMR and fractal theory

Dynamic imbibition and displacement between the matrix and fractures in shale reservoirs can significantly enhance oil recovery (EOR) following initial depletion. However, the microscopic production characteristics and seepage mechanisms at different pore scales during the dynamic imbibition process remain incompletely understood. In this study, we established an online physical simulation experiment method that combines dynamic displacement and imbibition based on nuclear magnetic resonance (NMR) and fractal theory, and a series of online NMR water flooding dynamic imbibition experiments were conducted. Through real-time dynamic monitoring of multiphase flow and migration behavior of crude oil in each stage of dynamic imbibition, the microscopic production characteristics and influencing factors were quantitatively studied from the recovery and residual oil saturation field distribution of different scale pores. Additionally, we developed a novel two-dimensional (2-D) NMR interpretation model to investigate the dynamic development characteristics of shale oil injection-imbibition-soaking-production integration, and the multiphase and multi-scale dynamic imbibition crude oil migration models were discussed. The results show that shale oil occurrence pores can be categorized into two types based on the corresponding production mode (imbibition + displacement). The water flooding dynamic imbibition process in shale reservoirs unfolds in three stages: strong displacement and weak imbibition stage characterized by the rapid production of large pores and fractures under displacement action; weak displacement and strong imbibition stage involving the slow production of small pores under reverse imbibition; and dynamic equilibrium stage characterized by weak displacement and weak imbibition. When viewing the entire water flooding dynamic imbibition process as an organism, it becomes imperative to maximize the recovery of large pores while ensuring the recovery degree of small pores. High permeability contributes to better pore throat connectivity and a greater imbibition and displacement production degree. The contribution of the.two production modes to the recovery of small and large pores increased by 4.67 % and 3.17 %, respectively. A negative correlation was observed between high displacement pressure and imbibition recovery, yet it is conducive to the contribution of displacement to total recovery. Notably, fractures can effectively reduce oil-water seepage resistance, and increase the contribution of displacement to recovery by 21.65 %. Finally.a positive correlation was noted between increased imbibition amount and free oil recovery, while residual oil gradually shifted towards adsorbed and organic matter-dominated forms, leading to decreased recoverability. Effectively utilizing the bridge flow conductivity of fractures, fluid imbibition displacement, and carrying effect is crucial for achieving optimal EOR. The findings provide theoretical support for clarifying the interaction between matrix-fracture imbibition and displacement and for the efficient development of shale oil.

Interferometric Radars for Bridge Monitoring: Comparison among X-Bands, Ku-Bands, and W-Bands

Interferometric radars are widely used sensors for structural health monitoring. They are able to perform dynamic measurements of displacement with sub-millimeter precision. Today, the Ku-band is the most common, due to the spread of commercial systems operating in this band. At the same time, the W-band sensors are gaining ever more interest. Other popular systems work in the X-band. Since the characteristics of the measurements dramatically depend on the operative frequency, it is essential to highlight their differences. For instance, higher frequency allows for high displacement resolution, but it is more subject to phase wrapping and decorrelation effects. In this paper, a direct comparison between radars operating in X, Ku, and W-band for bridge monitoring is carried out. The radars provide frequency-modulated continuous-wave signals. Experimental campaigns were performed both in controlled and realistic scenarios (a stayed bridge). The results of the experiments demonstrate that all the three sensors are suitable for performing dynamic structure monitoring despite their differences. It is worth noting that this comparative analysis has highlighted the role of amplitude variation in phase/displacement measurement. Regarding this point, the three different bands exhibit significant differences.

Improved pore structure characterization and classification of strong diagenesis sandstones by data-mining analytics in Tazhong area, Tarim Basin.

The Silurian system in Tazhong area is characterized by extensive, low-abundance lithological reservoirs with strong diagenesis, resulting in significant heterogeneity. The complex pore structure in this area significantly impacts fluid control, making accurate characterization and classification of pore structures crucial for understanding reservoir properties and their influence on oil and gas distribution. Based on 314 Mercury Injection Capillary Pressure (MICP) samples in combination with core slices and thin casting slices observation, a pipeline of characterization and classification scheme by data-mining analytics of strong diagenesis sandstone pore structure types in the study zone is established, and the characteristics of different pore structures are clarified. According to the pore structure parameter abstracted by MICP data compression and variable analysis based on hierarchical clustering and principal component analysis (PCA) analysis, the variables are reasonably evaluated and screened, and the screened variables can be divided into three groups: mean pore throat radius-maximum pore throat radius-median pore throat radius-pore throat diameter mean variable group, microscopic mean coefficient variable group, and median pressure displacement pressure-relative sorting coefficient variable group. The combination of classification schemes analysed by decision tree model and linear discriminant analysis (LDA) model was determined. In the two-dimensional projection diagram of LDA model, a relatively obvious distribution of low displacement pressure, middle displacement pressure and high displacement pressure was obtained, and three distribution lines were nearly parallel. Based on the relevant information, 6 combined classification schemes suitable for final pore structure modelling were determined verified by microscopic observation. The correct characterization and classification of pore structure can be applied to the prediction of pore type, which can be used to improve the prediction of oil and gas distribution and oil and gas recovery in the future.

Demographic and socioeconomic obstacles to access to malaria services for Myanmar migrants in Thailand

BackgroundTypically mobile and vulnerable, migrants face significant barriers to access to routine malaria prevention, diagnostics and treatment, which leads to unchecked malaria transmission, particularly in border regions with a high population displacement. This study aimed to investigate the demographic and socioeconomic obstacles to access to malaria services among Myanmar migrants residing in the Thailand–Myanmar border areas.MethodsA cross-sectional study was conducted in early 2024 across three districts near the Thailand–Myanmar border. Quantitative data were collected from Myanmar migrants using standardized questionnaires through structured surveys. Data analysis included descriptive statistics and simple and multiple logistic regression models.ResultsOut of 300 participants, approximately a quarter (27.3%) reported adequate access to comprehensive malaria services, including prevention, diagnostics, treatment and malaria-related health information. In multiple logistic regression models, factors associated with inadequate access included Myanmar migrants aged over 60 years (aOR: 7.63, 95% CI 1.74–20.58), accompanied by one to three family members (aOR: 3.33, 95% CI 1.06–8.45), earning monthly incomes below 3000 THB (aOR: 5.13, 95% CI 1.38–19.09) and 3000 to 6000 THB (aOR: 3.64, 95% CI 1.06–12.51), belonging to the Karen ethnicity (aOR: 2.13, 95% CI 1.02–3.84), with poor perception toward malaria (aOR: 2.03, 95% CI 1.03–4.01) and with poor preventive and health-seeking practices (aOR: 5.83, 95% CI 2.71–9.55).ConclusionsA significant proportion of Myanmar migrants encounter demographic and socioeconomic barriers to access to routine malaria services in Thailand. Tailored interventions are required to expand such access, including the recruitment of worksite health volunteers, strengthening the role of ethnic health organizations across the border and collaboration with private sector stakeholders (e.g. farm/company owners) to distribute preventive tools and ensure timely referral of suspected malaria cases to health facilities.

Low-temperature co-fired PNN-PZT-based multilayer piezoelectric actuator with low cost and high reliability

Developing low-temperature co-fired MLAs for the commercial application of micro-nano actuation and manipulation has recently become a research highlight. To simultaneously achieve high piezoelectric response and low co-firing temperature below 960 °C, a PNN-PZT-0.02 Sr piezoceramic incorporated with Li2O-Bi2O3-CuO sintering additives and its MLA with the dimension of 7×7×3 mm3 were prepared using tape-casting and subsequent co-firing methods. The piezoceramic mainly composed of a triple phase (M, R, and T) co-existence shows a dense microstructure, indicating a good sintering-assistance effect. Even sintering at 920 °C, the piezoceramic possesses d33 ∼ 683 pC/N and kp ∼ 0.64, possibly surpassing most reported PZT-based piezoceramics. The MLA co-fired at 940 °C possesses a good Ag-ceramic interface without holes, aggregation or delamination. Also, it shows high maximum displacement (≥ 20 μm), high stiffness (118.5 N/μm @ 150 V), excellent thermal stability and 109-cycle reliability. A flat and defect-free electrode morphology is conducive to decreased leakage current. However, high tanδ primarily induced by the residual glassy phase and (Pb, Bi) oxides is the drawback. These findings give a novel paradigm for low-cost and high-reliability MLAs using pure Ag as inner electrodes by triple-phase controlling and nano-heterogeneity.

Design, computational analysis and experimental study of a high amplification piezoelectric actuated microgripper

Increasing applications of compliant microgripper demands flexibility in working with a wide range of micro-objects which requires a large workspace, high precision motion, low parasitic motion, and satisfactory bandwidth control. To meet the requirement of pick and place manipulation tasks, a high amplification piezoelectric actuated microgripper is proposed and investigated in this paper. The high amplification of the microgripper is achieved using a compound amplifier. The compound amplifier is assisted to magnify the embedded piezoelectric actuator’s displacement. Two cascaded lever-type mechanisms are symmetrically connected with a bridge-type mechanism and form a three-stage amplification mechanism-based compound amplifier. Further, the four-bar parallelogram mechanisms are integrated with the third-stage displacement amplification mechanisms to linearize the output motion of the microgripper jaws. The characteristics of the microgripper were evaluated by computational analysis and validated using experimental investigations. Further, the design parameters are identified from the geometrical model of the individual displacement transmission mechanisms to perform a response surface optimization on the configured mechanism by the computational method. The design optimization of the microgripper resulted in a high displacement amplification ratio with a large workspace. The experimental investigations show that the designed microgripper is capable of achieving a high displacement amplification ratio of 34.5 and a total output displacement of 529.4 μm. Further, the characteristics of the microgripper such as motion resolution, and parasitic motion indicate that it will be able to perform high-precision micro-object grasping/releasing tasks.

Bank interaction effects on ships in 6 DOF

This paper presents the used mathematical formulations to predict ship bank interaction in six degrees of freedom (6 DOF) as applicable in a ship manoeuvring simulator. The mathematical models are based on a comprehensive database (+10,000 model tests carried out in a towing tank) and are capable to cope with a variety of realistic cross sections, based on a limited set of coefficients. Compared to previous publications on bank effects, the lateral force of these bank effects with point of application at the forward perpendicular, is now predicted with an alternative mathematical model that offers the same predictability as the original one, but that better describes the physical background. Moreover, new formulations are included to predict the bank induced components of the ship in the vertical plane (heel, midship sinkage and trim). Although these tend to be neglected, the experimental results show that the effect of confinement and eccentricity can be significant and that a 6 DOF mathematical model is needed for a correct prediction of the manoeuvring behaviour.A difficulty that is still present is the correct separation of the open water contribution and the contribution due to confinement. This is especially the case for rather high displacement ship models, such as the KVLCC2 tanker, in the 7 m wide towing tank, that even sense the tank walls when being towed on the centreline. This topic will be coped with in future publications, along with an extension for ships that sail with a drift angle.

Tectono‐sedimentary evolution of high‐displacement crustal‐scale normal faults and basement highs on rifted margins: Klakk Fault Complex and Frøya High, Mid‐Norwegian Margin

AbstractCrustal‐scale high‐displacement (>10 km) normal faults are not captured in existing tectono‐sedimentary models of rift basins. We used 2D and 3D seismic reflection and well data to perform a structural and source‐to‐sink analysis of the southern part of the Klakk Fault Complex and the western part of the Vingleia Fault Complex, Mid‐Norwegian rifted margin. The north–south trending Klakk Fault Complex has a zig‐zag to sinuous plan‐view geometry, forming a series of structural recesses and salients along strike. In cross‐section, the fault complex has a listric to convex‐up or low‐angle planar geometry with displacements above 20 km. This fault complex exhumed basement highs, the Frøya High and Sklinna Ridge, in its footwall and created a series of supradetachment basins, for example, the Rås Basin, in its hanging wall. In contrast, the northeast‐southwest trending Vingleia Fault Complex has a zig‐zag geometry in plan view and planar to listric geometry in cross‐section and displacement of up to 5 km. This fault has the Frøya High in its footwall and the southern Halten Terrace in its hanging wall. Restoration of selected structural cross‐sections shows a prominent fault‐parallel ridge, up to 15 km east of the Klakk Fault Complex interpreted as a palaeodrainage divide. This divide separates steep drainages developed along the west‐dipping footwall scarp to the Klakk Fault Complex, from broader, gentler east‐dipping drainages up to ca. 10 km long developed on a back‐tilted dip slopes along the eastern side of the Frøya High and Sklinna Ridge. Progressive headward erosion of active flank catchments was enhanced around topographically elevated structural salients to the point of capturing previous dip‐slope‐directed drainages during the earliest Cretaceous. A network of submarine canyons develop down‐dip of the drainage catchments along the Klakk Fault Complex scarp, whose geometries and length are controlled by their location with respect to the structural salients or recesses, and the presence of fault terraces. The middle Jurassic‐earliest Cretaceous synrift deposits form two seismic sequences that are filled with five distinctive seismic facies that record the evolution from a linked normal fault during rift climax to a high‐displacement stage. During the high displacement stage, exhumed local continental core complexes formed structural salients, separated along strike by structural recesses at the heads of supradetachment basins. Key elements of the high‐displacement fault stage include (i) the development of structural salients at sites of rift climax displacement maxima, (ii) development of supradetachment basins in rift climax displacement minima and (iii) migration of major depocentres away from the centre of rift climax fault segments. We synthesise these observations into a generic tectono‐sedimentary model for high‐displacement faults.

Local Gate Enhanced Correlated Phases in Twisted Monolayer-Bilayer Graphene.

Manipulating the flat band degeneracy and thus getting the correlated insulating phases has been an ideal thread for realizing the exotic quantum phenomenon in the moiré system. To achieve this goal, the delicately tuned twist angle and a substantial displacement field (D) are rigorously requested. Here, we report our scanning tunneling microscope (STM) work on reaching these correlated insulating states in twisted monolayer-bilayer graphene through a decorated tip. It acts as a local top gate, leading to an enhanced local D, and enables us to fully lift the 8-fold degeneracy of the flat bands. With the aid of this technique, we further expand the correlated insulating states into a more tolerant twist angle that is down to 0.92°. Moreover, the correlated insulating phases in the hole-doping regime are realized. Our tip decoration method allows us to integrate the STM study with the high displacement field for the correlated phases in the twisted moiré systems.

An improved dynamic Prandtl–Ishlinskii hysteresis model and a PID-type adaptive sliding mode controller for piezoelectric micro-motion platform

Piezoelectric actuators are widely used in the field of micro-nano driving due to their advantages of fast frequency response, high displacement resolution, large stiffness, small size, and low heat generation. However, the hysteresis non-linearity of piezoelectric actuators severely affects their positioning accuracy during operation. Therefore, the study of hysteresis model and compensation control for piezoelectric actuators has always been a hot topic in the field of micro-nano driving. However, existing hysteresis models and control methods cannot well describe the dynamic hysteresis curve of piezoelectric actuators and track the desired trajectory. To address this issue, this paper proposes an improved dynamic Prandtl–Ishlinskii (IDPI) model and a finite-time trajectory tracking adaptive sliding mode control method based on PID-type. Firstly, this paper introduces the construction and parameter identification method of the IDPI model. Secondly, the accuracy of the IDPI model in describing hysteresis curves under different input signals is verified through experiments, and the effectiveness of the feedforward controller based on the IDPI model is validated experimentally. Then, considering the modeling uncertainty, unmodeled internal dynamics, and external environmental disturbances of the piezoelectric micro-motion platform, a finite-time trajectory tracking adaptive sliding mode controller based on PID-type is designed to suppress the non-linear characteristics of the piezoelectric micro-motion platform. Finally, the performance of the compensator is verified through simulation experiments.

Investigation of gas residuals in sandstone formations via X-ray core-flooding experiments: Implication for subsurface hydrogen storage

The production and utilization of hydrogen (H2) as a clean energy source offer a promising solution towards achieving net-zero carbon emissions. Utilizing sandstone formations for geological hydrogen storage presents a viable option for the practical implementation of the hydrogen economy, offering both safe and large-scale containment capabilities. Accurate assessment of gas displacement behavior in porous media plays a critical role in understanding gas saturation, gas residual, and long-term storage duration. However, there are limited studies available on dynamic displacements for hydrogen storage applications. This study aims to enhance the understanding of gas flow behavior in sandstone rocks for different gas types and determine the role of capillary pressure and gas wettability during hydrogen storage. A series of gas core-flooding experiments are performed on a brine-saturated sandstone core sample using three different gases (CO2, CH4, and H2). X-ray scanning technique is applied to detect the gas saturation and gas residual after the core-flooding experiments. The results indicate that the average gas saturation ranges between 25 and 40%, with zero gas residual for all gases, suggesting that the gas residuals in this clean sandstone sample are unaffected by the gas type. Initially, the capillary pressure profile for the sample displayed low brine saturation at 200 psi, indicating very low capillary pressure in the sample due to the high permeability and large pore radius, despite the strong water-wetting behavior of the sample. Moreover, the obtained results indicate the high potential for gas recovery (especially for hydrogen during withdrawal cycles), and the high displacement efficiency in sandstone rocks. The reported low gas residual suggests that the wettability of the rock is not affected by gas injection, and it appears that the wettability and capillary pressure are not the controlling factors for gas storage in this sandstone sample. This observation suggests that the structural trapping mechanism is most likely to be the dominant trapping mechanism in this shallow high permeable sandstone rock. Also, the injection of cushion gases such as CO2 and CH4 indicated similar results to hydrogen injection, due to the low capillary pressure and high permeability in this sandstone sample. The findings of this study can greatly enhance the understanding of gas injection, displacement behavior, and gas residuals in sandstone rocks related to underground hydrogen storage.

A Review of Research on Improving Wear Resistance of Titanium Alloys

Titanium alloy is widely used as oil drill pipe material because of its light weight, high strength, good toughness, corrosion resistance, fatigue resistance, and good process performance. However, due to its low hardness, poor wear resistance, serious oxidation at high temperature (700 °C), and difficulty in lubrication, in oil and gas field exploration and development drilling, especially in deep wells, high displacement wells, horizontal wells, and highly deviated wells, wear and tear are prone to occur. The application and development of titanium alloys are greatly limited. This paper introduces the research status of the common surface modification technologies of titanium alloys, such as laser cladding, magnetron sputtering, plasma spraying, micro arc oxidation, etc. It points out the improvement effect of various modification technologies on the wear resistance and high-temperature oxidation resistance of titanium alloys and discusses the advantages and disadvantages of various modification technologies. A proposed method for enhancing the wear resistance and high-temperature oxidation resistance of titanium alloys was finally introduced, and its potential for future development was investigated.

Seismic Capacity of Reinforced Concrete Eccentric Braced Frame (EBF) With Vertical Link Using 20% GGBFS

EBF-V bracing is highly attractive due to its good seismic performance in high seismic zones. Vertical link beams as a component are capable of high elastic displacement and ductility to absorb lateral forces through shear-bending collapse mechanisms. However, the lateral load capacity of the bracing has to be sacrificed as it tends to decrease. The present study focuses on the capacity and lateral behavior of reinforced concrete eccentrically braced frame (EBF) with vertical link beam and tighter reinforcement spacing in the link beam in combination with GGBFS. GGBFS at 20% can improve the mechanical properties by reducing the pore number of the concrete due to the smaller particle size of OPC.This study uses CBF-V as a control to investigate the seismic behavior of tightly spaced transverse reinforcement (75 mm) in EBFs’s vertical link beam with eccentricities of 15 cm and 25 cm. In addition, the role of GGBFS was also observed through the displacement and ductility of the frame. As a result, the CBF has the highest plasticity. However, the tight reinforcement spacing of the vertical link beam in the EBF-V-15 results in the highest restraint, resulting in excellent stiffness and ductility through earthquake absorption with a shear collapse mechanism. In addition, GGBFS also plays a role in improving the collapse mechanism, which is characterized by large elastic displacement and high ductility.

Comparative Evaluation of the Application Effectiveness of Intelligent Production Optimization Methods in Offshore Oil Reservoirs

The development of offshore oil fields confronts challenges associated with high water cut and low displacement efficiency. Reservoir injection-production optimization stands out as an effective means to reduce costs and enhance efficiency in offshore oilfield development. The process of optimizing injection and production in offshore oil reservoirs involves designing strategies for a large number of wells and optimization time steps, constituting a large-scale, complex, and costly optimization computation problem. In recent years, with the rapid advancements in big data and artificial intelligence technologies, sophisticated evolutionary computation methods have found widespread application in reservoir injection-production optimization problems. However, the abundance of intelligent optimization algorithms raises the question of how to choose a method suitable for the complex optimization background of offshore oilfield injection-production optimization. This paper provides a detailed overview of the application of an existing differential evolution algorithm (DE), conventional surrogate-assisted evolutionary algorithm (CSAEA), and global–local surrogate-assisted differential evolution (GLSADE) in the context of practical offshore oilfield injection-production optimization problems. A comprehensive comparison of their performance differences is presented. The study concludes that the global–local surrogate-assisted evolutionary algorithm is the most suitable method for addressing the current challenges in offshore oilfield injection-production optimization.

Analysis and Optimization of a Novel Compact Compliant 2-DOF Positioner for Positioning to Assess Bio-Specimen Characteristics

A novel compact 2-DOF compliant positioner is developed for the purpose of achieving good characteristics such as high natural frequency, high displacement amplification ratio, good linear motion, and compact structure based on its symmetrical structure. To be specific, the developed stage is proposed according to an advanced six-lever displacement amplifier arranged at an inclination angle of the rigid bar utilizing right circular hinges and a parallel guiding mechanism with integrated flexure leaf hinges to attain the above-mentioned characteristics and reduce the decoupling mobility error. First, to quickly assess the initial quality response, an integration method of kinetostatic analysis, the Lagrange method, and finite element analysis was applied to evaluate and verify the quality characteristic of the stage. The experimental result showed that the error between the analytical method and the FEA method was 1.3%, which was relatively small and reliable for quickly assessing the primary quality response of the proposed positioner. Next, to boost the important output characteristics of the developed positioner, the integration approach of the response surface method and NSGA-II algorithm was utilized to find the optimal design variables. Finally, a prototype was manufactured based on the CNC milling method to validate the experimental and FEA analysis results. The attained results show that the optimal results of safety factor and output displacement were 2.4025 and 248.9 µm. Moreover, the FEA verification results were 2.4989 and 242.16 µm, with errors for safety factor and output displacement between the optimal result and the FEA result of 3.86% and 2.78%, respectively. In addition, the simulation and experimental results of the first natural frequency were 371.83 Hz and 329.59 Hz, respectively, and the error between the FEA result and experimental result for the first natural frequency was 11.36%. Furthermore, the achieved results show that the relationship between input displacement and output displacement of the experimental result and the FEA result of the developed structure achieved a good linear connection. These results suggest that the proposed positioner will be a potential structure employed in precise positioning systems and nanoindentation testing positioning systems for checking bio-specimens’ behaviors.

An integrated high precision absolute angular displacement sensor

Abstract This paper proposed a high precision absolute angular displacement time grating sensor, and was assembled into an integrated encoder. This absolute angle sensor contains two incremental sensors, namely, N1 measurement period fine measurement component and N2 measurement period coarse measurement component, N1 and N2 are mutually prime, and N1 > N2. The induction electrodes of the fine measurement component adopt differential design to minimize the effects of external electromagnetic interference and common mode interference between different sensing units so as to achieve high precision displacement measurement, the phase difference between two incremental sensor is used for absolute positioning. The reflecting ring design simplifies the structure of the encoder and facilitates sensor integration. The induction output signals of different components are cross connected through leads to the reflecting ring far away from the measurement component to the first harmonic error during the measurement period. The reading heads adopt a round, uniformly distributed design scheme, and the average effect of the whole circumference closed ring sampling scheme is beneficial for improving measurement accuracy and eliminating harmonic errors. A sensor prototype with a diameter of 83mm was manufactured and assembled into an integrated encoder. Experimental results show that the sensor achieve a precision of 12" over a full 360° measurement range and a resolution of 0.5", and it can realize absolute positioning.

Study of Retention of Drilling Fluid Layer on Annulus Wall during Cementing

To guarantee that the cement sheath has a sealing effect, it is best to replace the drilling fluid entirely and fill the annulus with cement slurry throughout the cementing process. A significant driving power and high stability at the interface between the cement slurry and drilling fluid are often necessary for achieving a high displacement efficiency. It is important that a comprehensive theoretical characterization is established on the thickness and location of drilling fluid retention and the conditions to prevent the formation of drilling fluid retention. In this study, firstly, the characteristics of annulus fluid shear stress distribution are analyzed by establishing the differential equation of shear stress distribution. Subsequently, the calculation model of the drilling fluid retention layer’s thickness is constructed. Subsequently, the impact of cement slurry and drilling fluid properties, eccentricity of the casing, and additional variables on the annular wall’s drilling fluid retention thickness are scrutinized. The quantitative conditions for preventing drilling fluid retention are also analyzed (i.e., Equation (23)). Based on the newly developed model, a case study is conducted to show the significance of the new model. This offers a theoretical foundation for enhancing cement injection displacement efficiency and cementing performance optimization.