Force Mechanism Research Articles

Optimal design of a new Halbach array magnetic roller with axial eddy current force

Non-ferrous metal recovery is of great significance to the sustainable development of resources. Small-sized nonferrous metal particles account for a large proportion of nonferrous metals in solid waste, but the recovery efficiency is low. Eddy current separation is an important technology for physical recovery of non-ferrous metals. Optimizing its magnetic roller is extremely important for improving the recovery efficiency and economy of small-sized non-ferrous metals. In this study, COMSOL Multiphysics is used to establish a three-dimensional transient simulation model of the vertical rotary-drum ECS. On the basis of the two-dimensional Halbach array magnetic roll, the magnetic system of the magnetic roll is designed in the axial direction, so that the particles are subjected to the axial eddy current force opposite to the direction of gravity for the first time. This force can slow down the falling velocity of particles, increase the difference in falling trajectory and repulsion distance, improve recovery efficiency. In addition, due to the generation of axial eddy current force, the interlayer dislocation type magnetic roller can achieve the same recovery effect by only using 1/3 of the length of the basic type magnetic roller. Based on the electromagnetic theory and particle dynamics, by comparing the axial magnetic density distribution of different magnetic rollers, the axial eddy current force and the trajectory of non-ferrous metal particles, the generation mechanism of the axial eddy current force and the magnetic system structure that can generate the axial eddy current force are clarified.

Numerical investigation on the rotor-turbulence interaction noise

Noise from a turbomachinery component, such as compressors and turbines, is an important issue to be resolved in aerospace and ocean engineering applications. The rotor of a turbomachinery assembly usually could operate downstream to other flow structures (fuselages, stators, control surfaces, etc.) that produce either large-scale or small-scale turbulence structures, which are highly complex and are being distorted while they are ingested into the rotor, which generate the rotor-turbulence interaction noise. The presented work conducted numerical simulation research on a ten-bladed rotor ingesting different turbulence structures. The large eddy simulation (LES) and Ffowcs-Williams and Hawkings (FW-H) methods were used to predict the flow-induced noise from the rotor. The results show that the time-space evolution of the upstream turbulent structure when it passes towards the rotor. In addition, the differences in the turbulence ingestion noise at different inflow speeds and rotational speeds were studied. Furthermore, the sound generation mechanism of turbulent ingestion noise was explored using a newly proposed near-field sound source analysis method. In summary, this study can help to improve the understanding of the physical mechanisms of unsteady forces and noise generated by a rotor when it interacts with ingesting turbulent flows.

Osnovnye tendencii razvitiya ekonomiki Ekaterinburga-Sverdlovska v 1922–1929 gg.

The study showed that the implementation of the new economic policy in Ekaterinburg-Sverdlovsk made a positive impact on the city's economy. The abolition of forced mechanisms of administration and the encouragement of private initiative in trade and industry caused the increase of the city's economy and contributed to the growth of its population.

The wounds of war and the scars of culture: Simone Weil and René Girard on the symmetry of violence

The philosophical discourses of violence developed in the 20th century can be grasped in two fundamental paradigms: the paradigm of force (Simone Weil) and the paradigm of domination (Horkheimer and Adorno). This article aims at situating René Girard’s theory of the culture within the paradigm of violence as an immediate force, stemming from Simone Weil’s phenomenological description of force in The Iliad. Simone Weil can be read as a model for modern reflection on violence in different ways. One of them can be identifying her interpretation of The Iliad as a starting point for the critique or even unmasking of blind reifying violence through the philosophy of culture: an example of this kind of translation can be found in Girard and his analyses of the figure of the scapegoat and rituals of violence, (sanctioned within myth), transferring violence into a sacral sphere. The pivotal point of the comparison is the concept of kydos, “the triumphant fascination of superior violence,” developed by Girard in Violence and the Sacred. The Greek term, which connects violence, understood in the mode of immediate force, with the magical and sacral dimension, serves as a key concept for comparison of the two thinkers’ conceptualizations of force. It allows interpretation of the conceptual tenets of Girardian theory, such as unanimity, symmetry, mimesis, and myth in the light of the key concepts of Weil, such as reification, symmetry, unawareness, and the blind mechanism of force. It also allows us to point out the discrepancies between the two conceptualizations (above all, the tensions between the rationality and irrationality of violence) and to grasp Girard’s theory as a philosophical commentary on Weil’s insights. This is going to fill a space on the map of modern discourses of violence.

Tunable magnetic properties and magnetic domain structure of nanocomposite permanent materials via Ti addition into Nd-Fe-Co-B alloys

In this work, the effect of tunable Ti content on the microstructure, magnetic domain structure, and magnetic properties of as-spun and annealed Nd9.5Fe79-xCo5TixB6.5(x = 0,1,2,3,4) alloys at the quench speed of 18 m/s were investigated. For the as-spun alloy, augmenting the Ti content enhanced the initial crystallization temperature and the stability of the amorphous phase. Simultaneously, the incorporation of Ti led to augmentation in the quantity of nanocrystals within the amorphous matrix, thereby facilitating the formation of vortex-like magnetic domains with large size but reduced the saturation magnetization Ms. For the annealed alloy, the incorporation of Ti inhibited the precipitation of α-Fe phase, refined the grain, enhanced the exchange coupling between the soft and hard magnetic phase and facilitated the formation of smaller, more uniform vortex-like magnetic domains, These alterations were beneficial to improve the comprehensive magnetic properties. Furthermore, the addition of tunable Ti resulted in a remarkable impact on coercivity enhancement. The coercivity value exhibited a significant increase of 54.30%, surging from 374.24 kA/m to 577.51 kA/m. Upon a thorough analysis of the magnetic domains and coercive force mechanisms, it was ascertained that the introduction of Ti substantially augmented the creation of vortex-like domains. These domains effectively impede domain motion, consequently elevating the material's coercivity.

Impact Force Mechanism of a Trimaran Model and Its Experimental Validation

In recent years, trimarans have been used in high-speed transport and in warships, but studies of them have made little progress. We designed a trimaran model and used it to perform a water-entry experiment to find a way to reduce the slamming pressure. The process of the model entering the water was divided into several steps, and different theoretical models were designed for each step, together with their force analysis. Relying on our experimental platform, we designed three flexible coating thicknesses and six drop heights as the different working conditions. With an analysis of the results under these experimental conditions, the experiment clearly indicates that the flexible cladding on the model can decrease the impact force when the model slams into water. Furthermore, the theoretical models and their corresponding force analyses are validated by the experimental results.

Active and passive safety enhancement for batteries from force perspective

Thermal runaway (TR) has become a critical issue for Li-ion battery applications in electric vehicles and energy storage stations. To address this issue, early warning and thermal runaway propagation (TRP) mitigation are significant for the active and passive safety of the battery system, respectively. This study proposes the expansion force as a reliable warning signal, which is proven to provide more interval (>500 s) for escape and rescue compared with voltage and temperature signals. Besides, the TR expansion force changing mechanism due to thermal expansion, gas generation/accumulation, and venting is investigated. Furthermore, the TRP expansion force and deformation changing mechanism is explained from the perspective of expansion, squeeze, and venting. The TRP debris deformation trend is verified through mechanical modeling. The maximum TR expansion force increment (ΔFmax)-capacity (Q) equalization and ΔFmax-cell index equations are proposed based on the TR/TRP tests of three types of prismatic batteries. Moreover, a TRP mitigation structure is proposed to amplify the TR expansion force, which is validated to effectively amplify the force, causing the mechanical destruction of the in-line module holder. A TRP mitigation test proves that the first TR cell capsizes the module holder to hinder the heat transfer between the front/back surfaces of the prismatic batteries when the TR expansion force exceeds the preload. Without enough heat transfer, the TR of the following battery cells cannot be triggered even under jet fire impact. This study guides the active and passive safety design for the prismatic battery system.

Single-grain scratching of SiCf/SiC composite under minimum quantity lubrication: Force and material removal mechanism study

As one of the most novel fiber-reinforced ceramic matrix composites, SiCf/SiC composites are difficult to be processed machine materials. On top of that, the underlying material removal mechanism not yet completely understood. Along these lines, in this work, single-grain scratching orthogonal tests with different MQL methods were carried out to systematically analyze the influence of the different processing directions and lubrication methods on the material removal lubrication mechanism and the scratching force in the scratched surfaces. From the acquired results, it was demonstrated that the scratch force was the smallest when the processing direction is was 0° to the fiber direction. In addition, the utilization of MQL from vegetable oil can effectively reduce the cutting force. Diamond indenter caused significant damage to the surface of SiCf/SiC composites when the machining direction was 90° to the fiber direction, while narrow but deep grooves on the surface were observed when the angle was 0°. The dominant mode of material removal of SiCf/SiC composites was a brittle fracture, and the damage features mainly included direct fiber breakage, matrix fragmentation, fiber pullout, and fiber outcropping. The increase of the processing ratio of 0° and implementation of vegetable oil for MQL was proven as one of the best methods.

Analysis and Experimental Verification of the Tangential Force Effect on Electromagnetic Vibration of PM Motor

In traditional analysis, several studies have discussed the vibration behavior of electric machines from the point of view of radial force. With the increasingly strict vibroacoustic index, the tangential force effects on the vibration are analyzed and investigated, and it shows the contribution of tangential force on electromagnetic vibration cannot be ignored. However, these studies are based mainly on finite element multi-physics models, and experiments are not conducted. Furthermore, the mechanism of tangential force is not clearly explained. In this paper, a special motor stator structure is proposed to explore the effect of tangential force on vibration. First, the analytical calculation of the tangential force and the tangential effect on motor vibration are described. Next, the Theorem of Translation of A Force is introduced to convert the effective tangential tooth force to a radial force couple acting on the stator yoke. Then, a novel motor stator is proposed to investigate the vibration characteristics caused only by tangential force, and the simulation is analyzed. Finally, a vibration test of the prototype is conducted and the result shows the tangential force can induce the radial vibration with corresponding order.

Influence of hBN nanofluid MQL on machining characteristics in turning of Inconel 625

Inconel 625 has a major component of nickel and chromium alloying elements. It is used in turbines and propeller shafts in aircraft engines. This study examines the impact of force, roughness, and wear mechanisms during the MQL-machining of Inconel 625 on the wt.% of nanofluids, cutting velocity, and feed rate. The experiments are carried out using an L20 orthogonal array. The cutting insert is PVD (TiAlN), and the nanofluid is hexagonal boron nitride mixed with the coconut oil. The findings indicated that low feed, low hBN concentration, and high turning speed resulted in a reduced cutting force value. A greater concentration value indicated a lower surface roughness, whereas increased speed and feed increased roughness. Based on analysis of optical micrograph, abrasion and adhesion wear are two modes of wear mechanisms.

State as a path breaker? Path-dependent behaviours and firm innovation: the moderating role of institutional forces

ABSTRACT This paper explores the effects and mechanisms of institutional forces on the relationship between path-dependent behaviours and innovation performance from an integrated framework combining path dependence and institution-based views. We first examine the effects of path-dependent behaviours, manifested as product line retention and extension, on incremental and radical innovation performance. In investigating this relationship, we join the institution-based view and propose that the effects of path-dependent behaviours are contingent on political and economic institutional forces. Using the samples of Chinese listed pharmaceutical enterprises from 2010 to 2016, we reveal that path-dependent behaviours are conducive to incremental innovation but detrimental to radical innovation. More importantly, while economic institutional forces can enhance the effects of these behaviours on both types of innovation, political institutional forces can mitigate their negative impact on radical innovation.

Exploration and Practice of Sustainable Development in Enterprise College

Enterprise colleges are conducive to promoting the reform of higher vocational education mode, comprehensively cultivating the comprehensive professional abilities of students in higher vocational colleges, and effectively improving the compatibility between talent cultivation and social needs. The construction of enterprise colleges should establish a three-level enterprise college system, establish an operating and evaluation mechanism for enterprise colleges, fully mobilize the enthusiasm of professional teachers to participate in school enterprise cooperation work, and solve the internal driving force mechanism of school enterprise cooperation.

On topology design of compliant constant output/input force mechanisms with contact interactions

We seek monolithic topologies for constant output (CoFM) and input (CiFM) force mechanisms using topology optimization. We capture large displacements, buckling, contact interaction between members and external surfaces, and importantly, interaction of the mechanism with flexible workpieces to accurately simulate force transfer. Features of constant force characteristics, e.g., magnitude(s) of the desired force(s), range of input displacement over which slope of the force–displacement curve is near zero, and distance between workpiece and the mechanism are controlled individually. Two constant output and constant input force mechanisms each, are synthesized using stochastic optimization ensuring ready manufacturability. We observe that (a) accurate modeling of the mechanism-workpiece interaction is important. (b) Fixed external surfaces may not necessarily contribute to contact force characteristics though interesting alternative solutions are possible in their presence. (c) It behooves to model self contact between members than to reject viable solutions wherein members intersect in intermediate configurations. We finally fabricate the synthesized mechanisms and find that the desired constant force characteristics are by-and-large retained qualitatively, even when the mechanisms may undergo plastic deformation.

Design of Novel Artificial Anal Sphincter

ObjectivesArtificial anal sphincter is considered to be a good method for the treatment of severe fecal incontinence, but there are problems of low biomechanical compatibility in clinical application. The purpose of this study is to design a novel artificial anal sphincter that can output stable loading force to solve the mechanical mismatch between artificial anal sphincter and intestinal tissue caused by excessive or too small local pressure on the intestine. Material and methodsAiming at the shortcomings of the existing artificial anal sphincter, a novel artificial anal sphincter with constant force mechanism is designed based on the C-shaped SMA sheet of Ti-55.9at%Ni and combined with the normal defecation mechanism of human body. In this paper, the chord length l of C-shaped SMA sheet is used as the design variable, and the artificial anal sphincter is optimized and verified initially by using finite element analysis method. ResultsThe results show that the artificial anal sphincter can achieve a constant force to clamp the intestine in a large displacement range when the chord length l of the C-shaped SMA is 13 mm, the chord height h is 1.5 mm, the width w is 2 mm, and the thickness δ is 0.2 mm. ConclusionThe design of artificial anal sphincter with constant force loading mechanism has a good effect in solving the biomechanical compatibility problem between the implant device and the intestinal tissue. In addition, the designed artificial anal sphincter occupies a small space, which provides a new idea for future clinical application.

Synthesis, crystal structure, cytotoxicity, in-detail experimental and computational CT-DNA interaction studies of 2-picolinate Pd(II) and Pt(II) complexes

A new Pd(II) complex of formula [Pd(en)(2-pyc)]+ (where, en is ethylenediamine and 2-pyc is 2-pyridinecarboxylate anion) and its reported Pt(II) analogue, i.e. [Pt(en)(2-pyc)]+ have been made by an improved synthetic procedure, yielding above 80%. They have been characterized by FT-IR, UV-Vis, 1H NMR, 13C NMR, conductivity and elemental analysis. Single crystal structural determination of [Pt(en)(2-pyc)]+ displayed that the Pt(II) cation in this complex coordinated by 2-pyc and en each as five member chelate resulting in slightly distorted square-planar array. The time-dependent spectroscopic analysis of these compounds in aqueous medium demonstrated their structural stabilities. The cytotoxic activities of Pd(II) and Pt(II) complexes, free 2-pyc and carboplatin (as standard drug) were assayed in-vitro against the HCT-116 and MCF-7 as cancerous and MCF 10 A and CCD-841 as normal cell lines. They showed the IC50 order of: carboplatin > 2-pyc > Pt(II) > Pd(II) and lower activities against non-cancerous cells. CT-DNA binding of the Pd(II), Pt(II) and 2-pyc free ligand were explored individually. In this relation, UV-Vis and fluorescence titrations disclosed quenching of CT-DNA absorption and emissions by the compounds via dynamic mechanism and formation of H-bonds and van der Waals forces between them. The interaction was further validated and verified by viscosity measurements and gel electrophoresis. Partition coefficient determination showed that all three compounds have more lipophilicity than cisplatin. Furthermore, docking analysis and molecular dynamics simulation were done to evaluate the nature of interaction between aforementioned compounds and CT-DNA. The finding results demonstrated that these agents interact with CT-DNA via groove binding and were in agreement with experimental results. Communicated by Ramaswamy H. Sarma

Numerical study on the force mechanism of the superstructure of offshore box bridge under tsunami actions

This paper presents a beam-pier structure model based on the Reynolds Averaged Navier-Stokes (RANS) equation and offshore box bridges to investigate the effect of tsunami-induced forces on the superstructure of offshore box bridges. The validity of the numerical simulation is substantiated through the comparison with wave surface theoretical solutions and experimental results. Subsequently, the force mechanism acting on the superstructure of offshore box bridges under tsunami actions is analyzed using the proposed model. The research results show that the peak value of horizontal and vertical forces can be divided into fluctuating growth stages and stable stages with different distances between the center of the section beam and the center of the pier. Notably, the vertical force peak is more susceptible to the pier compared to the horizontal force peak, while the overturning moment on the box girder by the pier has a significant influence. This study is of great significance in the realm of bridge failure modes identification and the formulation of measures aimed at disaster reduction and protection.

The effects of scratching speed in ultrasonic vibration-assisted single diamond scratching process

Ultrasonic vibration-assisted machining has been widely used in manufacturing hard and brittle materials. Previous studies have shown that the vertical ultrasonic vibration in ultrasound-assisted single diamond scratching can affect the scratching forces, surface quality, and material removal mechanism by two mechanisms: changing the contact mode between the single diamond and the workpiece and increasing the speed of the single diamond relative to the workpiece. However, some studies point out that increasing the speed has little effect on the scratching force and material removal mechanism. Therefore, it is necessary to conduct an investigation that takes into account the effects of both scratching velocity and ultrasonic vibration on scratching force, surface quality, and material removal mechanisms. In this study, the single diamond conventional scratching (CS) and ultrasonic vibration-assisted scratching (UAS) experiments have been conducted at different scratching speeds to investigate the material removal mechanism of ultrasonic vibration-assisted machining. The effects of increasing the scratching speed on cutting forces, material removal mechanism, and machined surface quality are investigated. The results show that in both CS and UAS processes with low to medium scratching speeds (less than1000 mm/s), increasing the scratching speed leads to more brittle material removal and lower surface quality. At the same time, the scratching speed has almost no effect on the scratching speed force.

Synthesis of linear thinned array based on improved binary brain storm optimization

In this paper, an improved binary brain storm optimization (ImBBSO) method is presented for pattern synthesis of linear thinned array. To avoid local convergence and obtain the global optimum, on the basic of original binary brain storm optimization (BBSO) algorithm, the designed method mainly modifies three aspects, containing the clustering centers selection, the forced bit transposition mechanism and the survival of population. The interactions of these three operations drive optimization variables to move toward a better direction. During optimization process, the formulated cost function balances the relationship among the number of active elements, the peak sidelobe level and the half power beam width, which are eventually in the best balance state after completing iterations. Besides, the subarray partition strategy is also integrated into the proposed optimization framework with slight amendments, which can be applied to many engineering fields with space restrictions. Finally, several numerical examples demonstrate the effectiveness and applicability of the proposed method compared with other existing results of state-of-the-art methods, whether in benchmarking functions or linear array application.

Extended spectral proper orthogonal decomposition for analysis of correlated surrounding flow structures and wind load components of a building

Proper orthogonal decomposition (POD) has been used in numerous studies in wind engineering to extract key features of a building's surrounding flow field and surface pressure, the connections between which, however, remain difficult to quantify. This study combined the extended POD with spectral POD (SPOD) method into a new method called extended SPOD (ESPOD) to correlate flow structures with surface pressure. SPOD wind force spectra were defined to quantify how much each pair of velocity and pressure modes contribute to the wind force on a building. The method was validated by a case study on a typical isolated high-rise building, in which periodic coherent structures were extracted to reveal the main mechanisms of the wind forces, including the influences from approaching turbulence, wake vortices, and conical vortices. Phase synchronization, which is utilized in ESPOD, is an effective criterion for distinguishing the multiple physical mechanisms at the same frequency. Additional information provided by the correlated velocity mode helps interpret the physical meanings of the relatively less informative pressure modes. Finally, compared to velocity-based approaches, the pressure-based approach can capture the wind force fluctuations more completely, and the velocity modes are not distorted too much by the non-optimal decomposition.

Interaction force mechanism for the improvement of reclaimed soil aggregate stability in abandoned homestead by different organic-inorganic soil conditioners

Reasonable application of organic-inorganic soil conditioners can effectively improve the structure and fertility of reclaimed soil in abandoned homestead. Aggregate stability is an important indicator to evaluate soil structure and fertility, and is largely influenced by soil internal forces (van der Waals attractive force, electrostatic repulsive force, hydration repulsive force) and particle surface properties. However, there are few studies on the influence of different soil conditioners on the reclaimed soil internal forces and its relationship with the aggregate stability. Therefore, we selected six different treatments of organic fertilizer (TO), fly ash (TF), maturing agent (TM), maturing agent + organic fertilizer (TMO), fly ash + organic fertilizer (TFO) and control (CK) to conduct a 5-year field experiment to study the effects of reclaimed soil particle interaction forces and surface characteristics on aggregate stability under the treatment of different soil conditioners. The results showed that with the application of soil conditioners, the soil organic matter (SOM), specific surface area (SSA), surface charge (σ0), cation exchange capacity (CEC), aggregate mean weight diameter (MWD) and Hamaker constant increased gradually, while the pH value decreased slightly. In particular, the MWD under the treatments of TFO and TMO increased by 150.3% and 65.6% respectively compared with that under the CK treatment. With the increasing application of soil conditioners, the electrostatic repulsive force and van der Waals attractive force between reclaimed soil particles increased constantly, but the net resultant force between particles decreased and the net attractive force increased continuously, thus improving the aggregate stability. Therefore, there is a significant negative correlation between the net resultant force among reclaimed soil particles and MWD and CEC. In addition, 10−2 mol L-1 is the critical concentration that affects the reclaimed soil internal force, and the organic-inorganic treatments of TFO and TMO can improve the net resultant force better. In a word, the particle interaction forces are important factors affecting the reclaimed soil structural stability, and this study provides a scientific reference for the rational selection of soil conditioners and its interaction force mechanism in the reclaimed soil improvement.