Internal Sleeve Research Articles

Chemically Synthesized ~1 nm Multilevel Capacitor‐like Particle with Atomic Precision

Can the chemically synthesized nanoparticles act as nanodevices or nanomachines? Herein, we demonstrated its feasibility. A novel nanocluster (ultrasmall nanoparticles) [Au44Cd20(m‐MBT)40][N(C8H17)4]2 (Au44Cd20 in short, m‐MBTH: m‐methylbenzenethiol) obtained via developing a synthesis method have a cannula‐like structure of the outer shell and an internal sleeve, revealed by single‐crystal X‐ray diffraction. Natural population analysis (NPA) charge calculations, charge carrier transport of Au44Cd20 (during which an intra‐nanocluster anti‐galvanic reaction was observed) after unneutral charging using NaBH4 and voltammetry proved the capacitor‐like character of Au44Cd20. The subsidiary capacitor‐like character of the outer shell of Au44Cd20 was further probed via NPA charge calculations and electrocatalytic reduction of CO2 to CO. Thus, this study predicts a new era of engineering metal nanoparticles for realizing atomically precise ultrasmall nanodevices and nanomachines.

Spatial conversion characteristics of sulfur and nitrogen via desulfurization denitrification under rapidly changing hydraulic conditions

The sulfur-nitrogen-contained wastewater treatment system needs fast start-up, efficient collaboration, and stability, to break through the application bottleneck of biological desulfurization-denitrification. An integrated sleeve bioreactor was adopted to analyze the coupling performances of sulfate-reduction and sulfide-based denitrification process. The spatial-temporal distribution of functional bacteria and genes was studied under rapidly changing hydraulic conditions. The transformation law of carbon-sulfur-nitrogen was clarified. The removal efficiencies of sulfate, total organic carbon, and nitrite reached 90 %, 98 %, and 99 %, respectively. Thermovirga, Desulfomicrobium and Desulfobulbus were the main functional bacteria in the external sleeve, while Sulfurovum and sulfurimonas were in the internal sleeve. The dominant functional genes sat, sqr, norBC, and nosZ had relative abundances of 1.02 ‰, 3.09 ‰, 0.63 ‰ and 0.51 ‰, respectively. The sleeve alleviated the toxic effects of sulfide and nitrite. It realized the spatial separation and enrichment of different dominant bacteria, improving the load shock resistance of bioreactor. The rapidly changing hydraulic retention time promoted the spatial transference of sulfate-reducing bacteria and brought the appearance of sulfide-based denitrification bacteria in external sleeve. It enhanced the stability of microbial community structure. This optimized microbial community structure provided a rich diversity of functional genes to ensure a collaborating degradation of sulfur and nitrogen. The main transformation pathways included the assimilated sulfate reduction, sulfur partial oxidation and denitrification. Rapidly decreasing hydraulic retention time facilitated the accumulation of elemental sulfur. The unique structure and operation exhibited strong resistance to loads and hydraulic shocks. This work provides a reference value for efficiently removing multiple pollutants in sulfur-nitrogen-polluted wastewater.

Deformation ability of steel inner sleeve T-joint in modular gymnasia based on 3D-DIC method

Substantial loads the roofs bear exert stringent performance standards on connecting joints in movable modular gymnasiums. Previously, we introduced a novel joint design, utilizing internal sleeves and bolts to integrate the upper and lower columns of modular units. To explore the actual deformation behavior and force distribution of this joint, this study employed a three-dimensional digital image correlation (3D-DIC) measurement method to visualize its full-field displacement and strain distribution. The reliability of the 3D-DIC results was confirmed through comparison with traditional measurement methods. Building upon this solid foundation, this study proceeds to assess the static performance of this innovative joint in two distinct directions, successfully revealing micro-deformation and local buckling phenomena undetectable to the naked eye. Notably, the quality of the welds connecting the beams and columns plays a pivotal role in ensuring the overall structural integrity of the joint. Under lateral loading conditions, the destructive behavior of the joints is primarily governed by material strength. Moment-rotation curves were plotted to delve further into the mechanical characteristics of the joint, revealing that the inner-sleeve T-joint exhibits the attributes of a rigid joint. Moreover, the primary damage modes observed in the specimens were fractures at the beam root or buckling of the column, with the joint area remaining intact. Consequently, this joint qualifies as a full-strength connection. These findings will deepen knowledge and understanding of this novel joint for designers.

Multibody Dynamics Model of the Cycloidal Gearbox, Implemented in Fortran for Analysis of Dynamic Parameters Influenced by the Backlash as a Design Tolerance

Abstract In this study, dynamical parameters of the cycloidal gearbox working at the constant angular velocity of the input shaft were investigated in the multibody dynamics 2D model implemented in the Fortran programming language. Time courses of input and output torques and forces acting on the internal and external sleeves have been shown as a function of the contact modelling parameters and backlash. The analysis results in the model implemented in Fortran were compared with the results in the 3D model designed using MSC Adams software. The values of contact forces are similar in both models. However, in the time courses obtained in MSC Adams there are numerical singularities in the form of peaks reaching 500 N for the forces at external sleeves and 400 N for the forces acting at internal sleeves, whereas in the Fortran model, there are fewer singularities and the maximum values of contact forces at internal and external sleeves do not exceed 200 N. The contact damping and discretisation level (the number of discrete contact points on the cycloidal wheels) significantly affect the accuracy of the results. The accuracy of computations improves when contact damping and discretisation are high. The disadvantage of the high discretization is the extended analysis time. High backlash values lead to a rise in contact forces and a decrease in the force acting time. The model implemented in Fortran gives a fast solution and performs well in the gearbox optimisation process. A reduction of cycloidal wheel discretisation to 600 points, which still allows satisfactory analysis, could reduce the solution time to 4 min, corresponding to an analysis time of 0.6 s with an angular velocity of the input shaft of 52.34 rad/s (500 RPM).

Whisk-Inspired Motion Converter for Ocean Wave Energy Harvesting

Inspired by hand push whisk blenders that are widely used in the kitchen, we here propose an energy harvester that enables conversion of low-frequency translational vibration to high-speed rotations and further generates electricity via the electromagnetic effect. The whisk-inspired energy harvester (W-EH) is composed of an internal thread sleeve, an external thread driving shaft, a spring, and a buoy. Compared with transmission approaches used by the electromagnetic power generators, the proposed design has the superiority of low cost, ultralow operation frequency (lower than 1 Hz), and high-power output. Tests in water indicate that the normalized power density is 300% higher than state of the art. Excited by mimicking ocean waves at 1.5 Hz, the W-EH prototype generates a maximum power of 64.4 mW and succeeds in lighting up 115 LEDs simultaneously, whose power is enough for continuous operations of most wireless sensors.

Release of powdery or granular substances from intact dangerous goods bags during road transport—Analysis of the causes and development of a test concept

AbstractThe leaks of dangerous goods from actually intact bags detected in the years 2018 to 2020 tend to be at an almost constant high level. These releases of powdery or granular dangerous goods represent violations of the sift‐proofness required in the dangerous goods regulations. This article first analyses the causes. The components of the bags that are affected by leaks are micro‐perforations, joins and closures, in particular internal sleeve valves. A distinction must be made between bags closed in conformity with or contrary to the manufacturer's instructions. The particle release is determined by a number of influencing factors of the filling substance, the packaging and other boundary conditions. Therefore, a comprehensive test concept is developed in this work, which takes all these factors into account. The application of this test concept facilitates the planning of the test setup and the experiments. On this basis, the complex mechanisms involved in the release of solid substances can be systematically investigated in the test laboratory. To prevent releases of powdery or granular substances from intact bags, it is necessary that the user has access to the closing instructions and the relevant properties of the test substance used for the design‐type approval. Further experimental investigations are needed to assess whether filling substances change their properties during transport and whether this enables them to escape.

Electrochemically Modulated Liquid Chromatography in Fused Silica Capillary Columns.

Electrochemically modulated liquid chromatography (EMLC) uses electrical potentials, applied to a conductive chromatographic stationary phase (e.g., porous graphitic carbon [PGC]), to manipulate analyte retention. This paper reports the design of a capillary EMLC column with a smaller internal diameter (ID; 250 μm) than that of the standard bore predecessor (3.3 mm ID). The new capillary EMLC columns are configured so that the PGC stationary phase serves as the working electrode in a two-electrode electrochemical cell and simplifies electrode placement by obviating the need for a counter electrode. This configuration also eliminates the internal Nafion sleeve that is critical to operation for the standard bore columns, thereby avoiding Nafion deformation as a source of chromatographic band broadening and rupturing as a mode of column failure. Indeed, values for chromatographic efficiency obtained on the capillary columns meet or exceed those measured for the standard columns (20 000-40 000 vs 14 000 plates/m, respectively) with near symmetric elution bands (asymmetry factors of 1.1-1.4 for well-packed capillaries) that surpass band symmetries observed in all prior studies. A test suite of aromatic sulfonates was used to characterize the chromatographic performance of the capillary EMLC columns. Separations of this test mixture showed that retention factors for individual analytes could be manipulated by as much as 21× by changing the applied potential at the PGC stationary phase. Changes in retention behavior at different potential ranges, hypothesized to result from differences in adsorption orientation, were also observed and are consistent with past work. Collectively, the retention behavior unique to EMLC is operative in this new capillary configuration and promises to open new avenues in tuning LC separations.

Influence of eccentricity of double eccentricity sleeves on the movements of swing head in rotary forging press

Abstract. Rotary forging is an innovative incremental metal forming process, In a rotary forging press with double eccentricity sleeves, the eccentricity of double eccentricity sleeves has significant effects on the movements of swing head. The internal and external eccentricity of the existing rotary forging machine is equal, except circular path, the rotation speed of internal and external eccentric sleeves for the rose curve, spirals curve and straight line is not equal, which will produce the oscillation centrifugal force during the forming process and cause the violent shaking on the machine. The shaking of the machine has an important influence on the life of the equipment parts machining accuracy and surface profile of parts, reducing the production efficiency. This paper proposes a method to reduce shaking by changing eccentricity and studied the influence of unequal eccentricity on the movements of swing head obtained the design relationship of internal and external sleeves eccentricity, which can reduce the shaking in rotary forging press. This study improving the working state of the rotary forging machine and economic benefits.

Effect of crystallizer structure on magnetic field distribution in melt

The distribution of magnetic field induced by pulse and differential pulse current was numerically investigated using a 2D axisymmetric mathematical model. Validity of the proposed simulation modeling was verified by measured experiment. The effect of coil turns, internal sleeve thickness, distance between coil and internal sleeve under pulse magnetic field (PMF) and coil spacing under differential pulsed magnetic field (DPMF) on magnetic field distribution were studied. The magnetic flux density and Lorentz force increase, the homogeneity of magnetic field decreases when coil turns increase, internal sleeve thickness and distance between coil and internal sleeve decrease under PMF. The homogeneity of the magnetic flux density distribution in the axial direction firstly increases and then decreases when coil spacing increases, the maximum Lorentz force is alternately distributed in the center of two coils and the coil spacing is optimally 20∼30 mm under DPMF.

Kinematics and dynamics of the two stage cycloidal gearbox

This article presents results of the numerical analysis of cycloidal gearbox, which were obtained in MSC Adams engineering software. Multibody geometry for dynamical analysis was designed in Autodesk Inventor Professional 2017 and imported in MSC Adams. The results of analysis are forces acting on the internal and external sleeves, position, velocity and acceleration of the selected points on the cycloidal gearbox’s moving components. Indirect result is time course of the torque at output shaft which was calculated on the basis of forces acting on the internal sleeves, which are parts of the equilibrium mechanism and displacements of these sleeves. Knowledge about cycloidal gearbox’s loading conditions is important in its design process. Main advantage of a cycloidal gearbox is distribution of the forces on multiple external sleeves, while in majority of other gears only one tooth is in contact at a time.

A laboratory study of stress arching around an inclusion due to pore pressure changes

When the pore pressure in a porous rock changes, stress arching will occur within the rock and the surrounding region. Stress arching ratio is defined as the total stress changes in the porous rock to the pore pressure change in the region. The region may have the same or different elastic moduli with the surrounding rock, which is usually referred to as inclusion or inhomogeneity. Stress arching is responsible for many geomechanical problems encountered during production or injection; in addition, it is a crucial parameter in stress estimation during field development. This paper aims to present laboratory measurements of vertical stress arching ratio in a material surrounding the inclusion (inhomogeneity). To the authors' knowledge, few laboratory experiments have been reported on direct measurement of stress arching. The inclusion is a cylindrical sandstone (44 mm in diameter and 50 mm in height) embedded in a larger cylindrical sandstone (150 mm in diameter and 154 mm in height), both of which are made synthetically. These two parts are separated and sealed by a internal polyurethane sleeve. Vertical stress changes are recorded by a mini hydraulic sensor embedded in surrounding rock. Laboratory results are compared to those obtained by numerical models. These models are checked with analytical formulations. The results of numerical models show a good agreement with laboratory data. The numerical results also indicate that the sensor response is affected by elastic properties of the internal sleeve. According to the sensitivity analysis performed, in the absence of the internal sleeve, properties of the inclusion have significant effects on the surrounding stress arching induced.

Influence of the length of the internal sleeve valve on the release of powdery substances from the closures of valved bags for dangerous goods

In practice, checks on dangerous goods transports often detect leaks of powdered dangerous goods from valved bags. In this work, the influence factors of a sudden release of powdery substances from the valves of valved bags were investigated. Drop tests were performed on paper bags of UN design type 5M2 with internal sleeve valve using 2 different powdery substances (Esplas H130 and zinc oxide “Rotsiegel”).The internal sleeve valves of all test samples were not sift‐proof with respect to both filling substances. For almost all test samples, the Esplas H130 powder already leaked out of pasted joints during manual filling. This is a contradiction to the requirement in UN 6.1.4.18.1, according to which closures and joints of paper bags 5M2 should be sift‐proof.In the drop tests, longer valve lengths had a greater sealing effect for both filling substances (for filling degrees of at least 95% and for test samples which had already been mechanically loaded). As an extreme example, at the drop height of 1.20 m and a filling degree of 100%, the released amount of zinc oxide powder from a 10‐cm‐long valve was about 16 times higher than from a valve length of 12.5 cm. The valve length is therefore a safety‐relevant parameter and should be specified by the manufacturer.To ensure that only filling goods with similar physical properties in comparison with the test substance are used for valved bags, the user must be informed of the particle size of the test substance.

English

The grouted splice sleeve connector system takes advantage of the bond-slip resistance of the grout and the mechanical gripping of reinforcement bars to provide resistance to tensile force. In this system, grout acts as a load-transferring medium and bonding material between the bars and sleeve. This study adopted the end-to-end rebars connection method to investigate the effect of development length and sleeve diameter on the bonding performance of the sleeve connector. The end-to-end method refers to the condition where reinforcement bars are inserted into the sleeve from both ends and meet at the centre before grout is filled. Eight specimens of grouted splice sleeve connector were tested under tensile load to determine their performance. The sleeve connector was designed using 5 mm thick circular hollow section (CHS) steel pipe and consisted of one external and two internal sleeves. The tensile test results show that connectors with a smaller external and internal sleeve diameter appear to provide better bonding performance. Three types of failure were observed in this research, which are bar fracture (outside the sleeve), bar pullout, and internal sleeve pullout. With reference to these failure types, the development length of 200 mm is the optimum value due to its bar fracture type, which indicates that the tensile capacity of the connector is higher than the reinforcement bar. It is found that the performance of the grouted splice sleeve connector is influenced by the development length of the reinforcement bar and the diameter of the sleeve.

Structural Performance of Grouted Sleeve Connectors with and without Transverse Reinforcement for Precast Concrete Structure

This paper presents the performance of the proposed grouted sleeve connector with and without steel spiral as transverse reinforcement under incremental tensile load until failure. The connector utilized mild steel pipe as sleeve where the sleeve consists of external and internal sleeve with the diameter of the external sleeve is larger than internal sleeve. The mild steel pipe and the steel spiral are used to confine and reinforce the grout and the two discontinued bars spliced end-to-end configuration in the sleeve. The test shows that, there are two modes of failure which were bar slipped and bar fractured outside the sleeve. Eleven specimens out of fourteen shows satisfactory results as it failed due to bar fractured outside the sleeve and achieve satisfactory ultimate tensile capacity. The stiffness and the ductility of the connectors also satisfy. Grouted sleeve connectors with steel spiral perform better compared to connectors without a steel spiral. The test shows that the performance of the grouted sleeve connector with or without steel spiral was governed by grout-bar bond, anchorage length and confinement action provided by the sleeve and the steel spiral. The connectors have a potential to be used in connecting precast concrete structure.

Nonlinear bend stiffener analysis using a simple formulation and finite element method

Flexible marine risers are commonly used in deepwater floating systems. Bend stiffeners are designed to protect flexible risers against excessive bending at the connection with the hull. The structure is usually analyzed as a cantilever beam subjected to an inclined point load. As deflections are large and the bend stiffener material exhibits nonlinear stress-strain characteristics, geometric and material nonlinearities are important considerations. A new approach has been developed to solve this nonlinear problem. Its main advantage is its simplicity; in fact the present method can be easily implemented on a spreadsheet. Finite element analysis using ABAQUS is performed to validate the method. Solid elements are used for the bend stiffener and flexible pipe. To simulate the near inextensibility of flexible risers, a simple and original idea of using truss elements is proposed. Through a set of validation studies, the present method is found to be in a good agreement with the finite element analysis. Further, parametric studies are performed by using both methods to identify the key parameters and phenomena that are most critical in design. The most important finding is that the common practice of neglecting the internal steel sleeve in the bend stiffener analysis is non-conservative and therefore needs to be reassessed.

Analysis of the factors involved in failure of a brass sleeve mounted on an electro-valve

Abstract Several electro-valves have failed because of the fracture occurred on the internal sleeve made in a typical free cutting leaded brass CW614 N (UNS 36000). The morphology of the observed fracture surface clearly indicates that the failure phenomenon has been ruled by a stress corrosion cracking mechanism. On the other hand, all the electro-valves operate in an environment featured by potable water that does not justify an alchaline concentration able to induce the SCC phenomenon. The analysis of the observed surface and the comparison of the stress that can induce SCC clearly point out that the failure has been induced by the application of excessive torque on the threaded sleeves to grant their fixing. The performed investigation allows us to indicate the correct procedure in order to avoid the failure of the sleeves and also the change of the applied alloy or an excessive increase of the resistant thickness of such a component.

State-of-art-review of electrochemical honing of internal cylinders and gears

This paper is an attempt to present a state-of-the-art review of two major applications of electrochemical honing (ECH) for internal cylinders and gears, which are the most commonly used parts in numerous engineering applications. ECH is a hybrid process of electrochemical machining (ECM) and mechanical honing, combining the fast material removal capabilities of ECM and controlled functional surface generating capabilities of mechanical honing in a single operation. ECH is a precision micro-finishing process capable of producing excellent surface quality having a cross-hatch lay pattern required for lubricating oil retention, compressive residual stresses required for the components subjected to cyclic loading, and completely stress-free surfaces. Furthermore, it provides these benefits productively. It makes ECH an ideal choice for superfinishing, improving the surface integrity, and increasing the service life of the critical components such as internal cylinders, transmission gears, carbide bushings and sleeves, rollers, petrochemical reactors, moulds and dies, gun barrels, etc., most of which are made of very hard and/or tough, wear-resistant materials generally susceptible to heat distortions. Consequently, ECH finds widespread use in the automobile, avionics, petrochemical, power generation, and fluid power industries. This paper presents a detailed description of the process principle, parameters, capabilities, equipment details, applications, and comprehensive literature review of past research work on the ECH of internal cylinders and gears along with some directions for future research with an objective to revive the interest of the global research community to mature this process further.

Effects of electromagnetic field and lubricate condition on the surface quality of magnesium alloy billet during LFEC processing

The microstructures of the magnesium billets could be improved markedly by low-frequency electromagnetic casting (LFEC) processing. In fact, the low-frequency electromagnetic field (LFEF) also has favorite effect on the surface quality of billet. However, few public reports on the surface quality of LFEC magnesium billets could be found. Therefore, a new crystallizer with a metal internal sleeve together with a kind of lubricant was designed aiming at lowing surface turning quantity, and the effects of casting velocity, electromagnetic condition and lubrication on the surface quality of magnesium billets were investigated. The results indicate that LFEF together with the lubricate condition would be responsible for the surface quality of the billets, and the high surface quality billets could be achieved by optimizing the casting conditions.

Multichannel Micromanipulator and Chamber System for Recording Multineuronal Activity in Alert, Non-Human Primates

We describe the design and performance of an electromechanical system for conducting multineuron recording experiments in alert non-human primates. The system is based on a simple design, consisting of a microdrive, control electronics, software, and a unique type of recording chamber. The microdrive consists of an aluminum frame, a set of eight linear actuators driven by computer-controlled miniature stepping motors, and two printed circuit boards (PCBs) that provide connectivity to the electrodes and the control electronics. The control circuitry is structured around an Atmel RISC-based microcontroller, which sends commands to as many as eight motor control cards, each capable of controlling eight motors. The microcontroller is programmed in C and uses serial communication to interface with a host computer. The graphical user interface for sending commands is written in C and runs on a conventional personal computer. The recording chamber is low in profile, mounts within a circular craniotomy, and incorporates a removable internal sleeve. A replaceable Sylastic membrane can be stretched across the bottom opening of the sleeve to provide a watertight seal between the cranial cavity and the external environment. This greatly reduces the susceptibility to infection, nearly eliminates the need for routine cleaning, and permits repeated introduction of electrodes into the brain at the same sites while maintaining the watertight seal. The system is reliable, easy to use, and has several advantages over other commercially available systems with similar capabilities.

Improving the Ductility of Knee Joints between Rectangular Hollow Sections

This paper proposes a new welding-based solution that significantly increases the rotation capacity of a stiffened welded knee joint between cold-formed rectangular hollow sections under opening moment. The proposed solution is more economical than the use of internal sleeves and can be applied to new as well as existing structures. The solution involves the use of extra layers of weld on the inner (tension) flange of a stiffened welded knee joint. Laboratory test results are presented to demonstrate that the solution enabled such a joint between DuraGal C450 150×50×4 or 150×50×5 rectangular hollow sections manufactured to AS 1163 to satisfy the rotation capacity requirement specified for plastic design of steel frames. The reason why the new solution results in increased rotation capacities is explained in terms of strain redistribution and strain reduction in the tensile regions around the knee joints.