Shape Change Process Research Articles

RobotSDF: Implicit Morphology Modeling for the Robotic Arm.

The expression of robot arm morphology is a critical foundation for achieving effective motion planning and collision avoidance in robotic systems. Traditional geometry-based approaches usually suffer from the contradiction between the high demand for computing resources for fine expression and the insufficient detail expression caused by the pursuit of efficiency. The signed distance function addresses these drawbacks due to its ability to handle complex and arbitrary shapes and lower computational requirements. However, conventional robotic morphology methods based on the signed distance function often face challenges when the robot moves dynamically, since robots with different postures are modeled as independent individuals but the postures of robots are infinite. In this paper, we introduce RobotSDF, an implicit morphology modeling approach that can express the robot shape of arbitrary posture precisely. Instead of depicting a whole model of the robot arm, RobotSDF models the robot morphology as integrated implicit joint models driven by joint configurations. In this approach, the dynamic shape change process of the robot is converted into the coordinate transformations of query points within each joint's coordinate system. Experimental results with the Elfin robot demonstrate that RobotSDF can accurately depict robot shapes across different postures up to the millimeter level, which exhibits 38.65% and 66.24% improvement over the Neural-JSDF and configuration space distance field algorithms, respectively, in representing robot morphology. We further verified the efficiency of RobotSDF through collision avoidance in both simulation and actual human-robot collaboration experiments.

The Effect of Lens Shape, Zonular Insertion and Finite Element Model on Simulated Shape Change of the Eye Lens

The process of lens shape change in the eye to alter focussing (accommodation) is still not fully understood. Modelling approaches have been used to complement experimental findings in order to determine how constituents in the accommodative process influence the shape change of the lens. An unexplored factor in modelling is the role of the modelling software on the results of simulated shape change. Finite element models were constructed in both Abaqus and Ansys software using biological parameters from measurements of shape and refractive index of two 35-year-old lenses. The effect of zonular insertion on simulated shape change was tested on both 35-year-old lens models and with both types of software. Comparative analysis of shape change, optical power, and stress distributions showed that lens shape and zonular insertion positions affect the results of simulated shape change and that Abaqus and Ansys show differences in their respective models. The effect of the software package used needs to be taken into account when constructing finite element models and deriving conclusions.

Analysis and tests of non-uniform wrapping process of tape spring

A tape spring, which has a high ratio of retraction and deployment, is a type of basic deployable member that plays an important role in deployable structures. This paper is focused on the non-uniform wrapping process of a tape spring that the fixed end section preserves the initial shape. A theoretical method is presented to predict the non-uniform wrapping process of a metallic tape spring based on classical theories about the bending behavior of this type of tape spring. There are two possible shapes for a tape spring after the non-uniform wrapping process, namely a polygon or a continuous curve. The boundary lines of the two possible shapes are studied, and it is shown that the shape depends on the radius of the central cylindrical hub. A finite element model is built using the commercial software ABAQUS to verify the reliability of the theoretical model. Experimental measurement is also conducted to record the shape change process of a tape spring. The comparisons of the results of the three different methods show that they are in good agreement with each other, which means that the theoretical model can be used to predict the non-uniform wrapping behavior of the tape spring. Additionally, the behavior of four tape springs during the non-uniform wrapping process is studied, and the results show that the shapes of multiple tape springs in a coiled state correspond to that of a single tape spring.

The future of leadership: new digital skills or old analog virtues?

PurposeBusiness leaders are facing a change of role as digitalization continues to intensify in organizations. As technological change is bringing back supposedly old virtues of leadership, this study aims to explain the impact digital transformation has on leadership due to organizational size.Design/methodology/approachCross-border study with experts from multinational enterprises (MNEs) in Austria and small and medium companies (SMEs) in Italy.FindingsWith increasing digitalization, leadership is becoming more important. In times of social distance, it is essential that leaders actively foster the management of relationships with their employees, manage social processes in their teams and shape change processes. This requires a bundle of skills consisting of effective leadership skills, strong change management skills and conceptual digitization skills.Practical implicationsDigital transformation is not mainly about implementing new technologies; it is about developing an appropriate strategy in which people are key. Organizations regardless of size need to recognize that digital transformation requires not less, but even more active shaping of the relationships between leaders and their team members. Consequently, they need active leaders who drive, communicate and implement technological change. As leadership and change require time, resources and, above all, attention, executive selection and qualification are critical for the broad integration of digitalization ideas into an organization.Originality/valuePeople, not technology, drive digital transformation, and organizations require leaders, not necessarily technological specialists, to manage the complex changes that comprise an organization’s digital transformation. Technical and methodological skills can be substituted with the use of new technologies, but leaders’ interactional, social, strategic and conceptual skills are gaining in importance.

Inferring Dynamic Fragmentation Through the Particle Size and Shape Distribution of a Rock Avalanche

AbstractOn 28 August 2017, a large catastrophic rock avalanche occurred in Nayong, Guizhou Province, China. It claimed 35 lives and caused large property losses. The Nayong rock avalanche provides a rare opportunity to infer the dynamic fragmentation of rock masses from deposits. Field surveys combined with an uncrewed aerial vehicle image analysis system were performed to investigate the particle size and shape distribution along the runout path of the Nayong rock avalanche. The Weibull particle size distribution (PSD) model was tested and possesses the highest accuracy and capability over the entire range of the Nayong rock PSD, and it shows that the median size (D50) values of the particles range from 0.16 to 16.31 m along the runout path. Moreover, the evolution of D50 along the runout path confirms that the degree of rock fragmentation varies greatly in different regions. Additionally, the relative breakage (BR) of particles in the deposition area is 0.191. Particle R values increase significantly from 0.55 to 0.78 along the runout path, which indicates that the rock grinding (shape change) process continuously occurs throughout the avalanche path. The image analysis results confirm that the dominance of rock fragmentation and grinding alternates during granular flow transport. Based on these results, the classic fragmentation‐spreading model for long‐runout rock avalanches is optimized by taking into account the method by which grinding rocks increases the speed of avalanches.

Particle-based model of mechanosensory contractility kit assembly

Cell shape change processes, such as proliferation, polarization, migration, and cancer metastasis, rely on a dynamic network of macromolecules. The proper function of this network enables mechanosensation, the ability of cells to sense and respond to mechanical cues. Myosin II and cortexillin I, critical elements of the cellular mechanosensory machinery, preassemble in the cytoplasm of Dictyostelium cells into complexes that we have termed contractility kits (CKs). Two IQGAP proteins then differentially regulate the mechanoresponsiveness of the cortexillin I-myosin II elements within CKs. To investigate the mechanism of CK self-assembly and gain insight into possible molecular means for IQGAP regulation, we developed a coarse-grained excluded volume molecular model in which all protein polymers are represented by nm-sized spheres connected by spring-like links. The model is parameterized using experimentally measured parameters acquired through fluorescence cross-correlation spectroscopy and fluorescence correlation spectroscopy, which describe the interaction affinities and diffusion coefficients for individual molecular components, and which have also been validated via several orthogonal methods. Simulations of wild-type and null-mutant conditions implied that the temporal order of assembly of these kits is dominated by myosin II dimer formation and that IQGAP proteins mediate cluster growth. In addition, our simulations predicted the existence of “ambiguous” CKs that incorporate both classes of IQGAPs, and we confirmed this experimentally using fluorescence cross-correlation spectroscopy. The model serves to describe the formation of the CKs and how their assembly enables and regulates mechanosensation at the molecular level.

Modeling contractility kit mediated mechanosensation and cytoskeletal network assembly

The mechanobiome consists of a meshwork of macromolecules that determines cellular mechanical properties and enables mechanosensation, facilitating shape-change processes such as proliferation, polarization, migration, and cancer metastasis. Myosin II and cortexillin I, critical elements of the mechanobiome, pre-assemble in the cytoplasm into complexes known as mechano-contractility kits (MCKs). IQGAP scaffolding proteins regulate the mechano-responsiveness of the cortexillin I-myosin II elements within MCKs.

Simulation of behavior of wheel on uneven surfaces

A wheel contacts with a rail on the track. Therefore, wear occurs at the contact area between the wheel and the rail. Wear on the wheel and the rail gradually progresses because the wheel and the rail contact with each other constantly. Then, periodic unevenness occurs such as wavy wear on the rail. This wear causes amplification of vibration during driving. This phenomenon leads to various problems, such as deterioration of riding comfort and noise. As a countermeasure, the rail is scraped to remove rail irregularities. However, it is costly. Therefore, if the contact conditions between the wheel and the rail that reduce wheel-rail wear are clearly, it may lead to lengthen the grinding cycle and cost saving. However, it is difficult to observe the process of shape change with time such as wear. Therefore, we focused on DEM. In this study, circular particles arranged in a regular pattern are regarded as rails in DEM. The behavior of the wheel when it runs on the rail was investigated. On the other hands, running experiments were conducted using this model, and the results of the experiments and analysis were compared. As a result, in the analysis, it was found that the vertical acceleration level of the wheel particles increases as the rail particle spacing increases. Also, in the experiment, it was found that the acceleration level increases as the wheel and rail wear.

『說文』省聲⋅省形字의 재구조— 戰國 出土文獻의 몇 가지 예를 근거로

This study checks the classification contents of the generated organisms in “shuowen” through an advisor by referring to the classification of existing studies on the generated organisms, and analyzes the spherical cause. Abbreviated significand abbreviated phonetic is an additional analysis method other than the “six principles theory of Chinese script” system used as “從某, 從某省” of syssemantograph or “從某省, 某聲” of phonogram in the “shuowen” system. Existing researchers analyzed the attribution and assistant process of the creator or of “shuowen” according to their respective criteria. They also summarized examples of analysis based on ancient script form but as literature from the National Era was excavated, a new basis for estimating the process of shape change was prepared. Therefore, this study also believes that additional analysis of abbreviated significand abbreviated phoneticis necessary, and examines the graphic component relationship of abbreviated significand abbreviated phonetic through text analysis in the national era, and further examines the cause of formation of abbreviated significand abbreviated phoneticis. This study analyzed through national text using actual examples in Chapter 3. It can be seen that most of the letters that attempted to be analyzed as “abbreviated significand abbreviated phonetic” reflect phenomena such as “modified tone” and “apperception”, which are spherical features of the “Paleography stage”, and several meanings can be found below. First, when “abbreviated significand abbreviated phonetic” misrepresented the letter, it was found that the original meaning and interior of the letter were unknown mainly due to “corruption” and “consolidation” of the letter. Second, the letters interpreted as “abbreviated significand abbreviated phonetic” could be analyzed in different coined and spherical methods for each era. This was able to confirm the process of the at the ancent characters stage. Third, when the classification of unilateral among the abbreviated significand abbreviated phoneticis characters was incorrectly induced, the shape of the unilateral unit as well as the graphic unit mainly played a central role in form-meaning, reflecting the derivational method and the organization method.

Layered shock-resistant element parts shape change process selection and modeling

An impact-resistant layered element consisting of two outer layers from highly rigid material and an inner layer from viscoelastic material has been developed. The item reduces the barring effect on the protected object. The design peculiarity is that the outer part has a bend with a deflection arrow within 10… 15 thicknesses, and has a connection of the outer layers from high-stiff material on opposite edges with staples from plastic material, which during plastic deformation flows into the edge holes coaxially in the outer layers, on the inner side of the impact-resistant element is attached a shock-absorbing layer from elastic foamed polymeric material, the back surface of which corresponds to the surface of the protected object. For the parts manufacture it has been developed bending sheet parts method in which the bending the part shelves with a bending element with their subsequent straightening. The aim is to increase the process productivity and the geometric dimensions’ accuracy of the part. Modeling the process of parts spontaneous forming "Impact-resistant element upper sheet" on the reverse and direct schemes is performed by the finite element method in the AnSYS / AutoDYN system. The study purpose is to develop technology and modeling the process of the impact-resistant element sheet parts deformation.

Occurrence of shape change in rechargeable alkaline zinc electrodes observed by operando confocal optics and X-ray diffraction

Alkaline secondary batteries with zinc negative electrodes are attractive power sources for large-scale energy storage systems. However, low cyclabilities of zinc electrodes prevent their wide applications. While shape change has been known as one of the predominant degradation modes, its origin has not been clarified yet. In this study, we analyze the initial charge-discharge behavior of ZnO composite electrodes using a unique “laboratory” operando observation method combining confocal optics and X-ray diffraction to capture the occurrence of shape change and elucidate the mechanisms. It is shown that the ZnO composite electrodes in 4.0 mol dm −3 KOH solution, which show relatively short cycle life, suffers from uneven reactions caused by spatially concentrated metallic zinc depositions on charging and significant ZnO dissolutions on discharging, whereas those in 1.0 mol dm −3 KOH solution and the ionomer-modified electrodes in 4.0 mol dm −3 KOH with improved durability exhibit uniform formation of metallic zinc and ZnO precipitation during charge-discharge cycles. We thus conclude that the occurrence of the shape change processes limiting the cycle life is essentially ascribed to the spatially uneven reactions in the zinc electrodes. • Initial charge-discharge behaviors of ZnO composite electrodes are analyzed. • Operando confocal optics and operando X-ray diffraction are combined. • The occurrence of the shape change is ascribed to the spatially uneven reactions.

An Investigation into Accumulative Difference Mechanism in Time and Space for Material Removal in Micro-EDM Milling.

In micro-electrical discharge machining (micro-EDM) milling, the cross-section of the microgroove machine is frequently not an ideal rectangle. For instance, there are arc shapes on the bottom and corners, and the sidewall is not steep. The theoretical explanation for this phenomenon is still lacking. In addition to the tip discharge effect, the essential reason is that there is an accumulative difference in time and space during the shape change process of a tool electrode and the microstructure formation on a workpiece. The process parameters are critical influencing factors that determine this accumulative difference. Therefore, the accumulative difference mechanism in time and space is investigated in this paper, and then a theoretical model is developed to simulate the micro-EDM milling process with a straight-line single path. The simulation results for a cylindrical electrode at the two rotational speeds of 0 (nonrotating) and 300 rpm are compared, while the results for a cylindrical electrode and a square electrode at a rotation speed of 0 are also compared to verify that different process parameters generate accumulative differences in the time and space of material removal. Finally, micro-EDM milling experiments are carried out to verify the simulation model. The maximum mean relative deviation between the microgroove profiles of simulation results and those of experiments is 11.09%, and the profile shapes of simulations and experiments have a good consistency. A comparative experiment between a cylindrical electrode and a hollow electrode is also performed, which further verifies the mechanism revealed in the study. Furthermore, the cross-section profile of a microgroove can be effectively controlled by adjusting the process parameters when utilising these accumulative differences through fabricating a microgroove with a V-shaped cross-section by a square electrode and a microgroove with a semi-circular cross-section by a cylindrical electrode. This research provides theoretical guidance for solving the problems of the machining accuracy of detail features in micro-EDM milling, for instance, to machine a microgroove with an ideal rectangular cross-section.

The shape change process of the ASC

The shape change process of the ASC

Recovery from alcohol problems in the absence of treatment: a qualitative narrative analysis

Recovery from alcohol problems in the absence of treatment or mutual-aid is very common, but under-researched. This study explores the lives of people who had resolved their alcohol problems without treatment, seeking to situate experiences of recovery in social contexts and broader life narratives. The in-depth qualitative interviews were aided by a life-history methodology that invited participants to account retrospectively for their lives. A narrative analysis was undertaken. Two major cities (Sydney and Melbourne) in Australia. People who had resolved an alcohol problem in the absence of treatment (n=12) were recruited from the general community using convenience sampling. Eligible participants had received 'minimal treatment' for an alcohol use disorder: fewer than three sessions in an outpatient treatment programme or nine sessions with mutual-aid groups (e.g. Alcoholics Anonymous), or having accessed mental health treatment for problems other than drinking at least 2years prior or 1year after having resolved an alcohol problem. Participants were considered to have had an alcohol use disorder if they reported two or more symptoms (DSM-V) within a 1-year period prior to the past year, using questions endorsed by the National Institute on Alcohol Abuse and Alcoholism (NIAAA). People were considered to have resolved their alcohol use disorder by responding to the recruitment message calling for people who "used to have an alcohol problem but no longer do". The Alcohol Use Disorders Identification Test (AUDIT-C) was used to understand participant's drinking behaviours in the past 12months. Four different narratives were identified in the analysis. In the emancipation narrative, identity development and major changes across the life-curve were associated with separating oneself from an oppressive circumstance. In discovery narratives, art culture and other consciousness-expanding experiences were sources of identity development, but sometimes a barrier to alcohol recovery. In mastery narratives, life events were understood as failures or successes, and recovery was positioned as an individual journey accomplished through increased problem awareness. Finally, in coping narratives, changes were understood as a series of continuous struggles, and recovery was made sense of through diagnostic discourses. People who resolve an alcohol use disorder in the absence of treatment or mutual-aid appear to explain their recovery in terms of at least four different life narratives: emancipation, discovery, mastery or coping. Social contexts and cultures outside the treatment setting, and the various identities and narratives they provide, shape change processes.

Quality Improvement for Large Diameter Welded Pipes Using a Modeling Method for the Shape Change Processes of Sheet Billet

Quality Improvement for Large Diameter Welded Pipes Using a Modeling Method for the Shape Change Processes of Sheet Billet

Multi-Stimuli-Triggered Shape Transformation of Polymeric Filaments Derived from Dynamic Covalent Block Copolymers.

Using dynamic polymers to achieve the morphology transformation of polymeric assemblies under different conditions is challenging. Herein, we reported diversiform shape transformation of multi-responsive polymer filaments, which were self-assembled by a new kind of amphiphilic block copolymer (PVEG-PVEA) possessing dynamic and reversible acylhydrazone bonds through reacting benzaldehyde-containing block copolymers poly(vinylbenzaldehyde)-b-poly(N-(4-vinylbenzyl)-N,N-diethylamine) (PVBA-PVEA) with acylhydrazine-modified oligoethylene glycol. It was found that the resulting amphiphilic and dynamic PVEG-PVEA was capable of hierarchically self-assembling into intriguing core-branched filaments in aqueous solution. Notably, the features of acylhydrazone bonds and PVEA block endow the filaments with multi-responsiveness including acid, base, and temperature, leading to the multiple morphological transformations under such stimuli. Moreover, the core-branched filaments would further transform into polymeric braided bundles driven by hydrogen-bonding interactions of amide bonds. It is noteworthy that both core-branched filaments and braided bundles made from polymers are quite rare. These diversiform polymeric assemblies and their morphological evolution were characterized by TEM, Cryo-TEM, SEM, and DLS. Finally, we used PVBA-PVEA as a platform to facilely prepare functional polymers, such as glycopolymers via the reaction of amino-containing sugars and aldehyde groups. The obtained glycopolymers self-assembled into glycofibers for the biomimicry of glycans via binding with lectins. These findings not only are conducive to understanding of the stimulated shape change process of dynamic polymeric assemblies in water but also provide a new method for the facile fabrication of smart and functional polymeric assemblies for different potential applications, such as biomimicry and targeted drug nanocarriers or delivery vehicles.

Safety performance of self-expandable NiTi alloy stent

In order to evaluate the safety performance of self-expandable NiTi alloy stents systematically, the dynamic safety factor drawn up by International Organization for Standardization, was used to quantitatively reflect the safety performance of stents. Based on the constitutive model of super-elastic memory alloy material in Abaqus and uniaxial tensile test data of NiTi alloy tube, finite element method and experiments on accelerated fatigue life were carried out to simulate the self-expansion process and the shape change process under the action of high and low blood pressure for three L-type stents of Φ8×30 mm, Φ10×30 mm, Φ12×30 mm. By analyzing the changes of stress and strain of self-expanding NiTi alloy stent, the maximum stress and strain, stress concentration position, fatigue strength and possible failure modes were studied, thus the dynamic safety factor of stent was calculated. The results showed that the maximum stress and plastic strain of the stent increased with the increase of grip pressure, but the maximum stress and strain distribution area of the stent had no significant change, which were all concentrated in the inner arc between the support and the connector. The dynamic safety factors of the three stents were 1.31, 1.23 and 1.14, respectively, which indicates that the three stents have better safety and reliability, and can meet the fatigue life requirements of more than 10 years, and safety performance of the three stents decreases with the increase of stent's original diameter.

Mapping the Biochemical Interactions of the Mechanoresponsive Contractility Controller

Every biological process, ranging from cell migration to embryogenesis, relies on the cell's ability to adapt to changing mechanical environments. By studying the model shape change process cytokinesis in Dictyostelium, we find that the cell is a finely tuned control system, with proteins that modulate their behavior in response to mechanical and biochemical signals. Although we know many of the players involved in the contractility controller, their biochemical interactions that allow force propagation through the cortical network are still poorly defined. We use a proteomics approach to identify direct interactors of two key nodes of the control system, actin crosslinker cortexillin I and scaffolding protein IQGAP2. This analysis identifies mechanoenzyme myosin II as a biochemical interactor of both cortexillin I and IQGAP2. We use quantitative in vivo biochemical measurements, including fluorescence cross-correlation spectroscopy (FCCS) and Single Molecule Pulldown (SiMPull) to measure concentrations, apparent binding affinities, and stoichiometries of complexes. We find that the cooperative mechanoaccumulation of myosin II and cortexillin I is potentially due to their direct interaction. IQGAP1, in turn, competes with IQGAP2 to bind myosin II and cortexillin I, thus negatively regulating contractility. Our data also suggest that multi-protein complexes are pre-formed in the cytoplasm, primed for activation by chemical or mechanical stimuli to engage with the cytoskeletal network. In addition, we find a few unusual interactors by mass spectrometry analysis, such as RNP1, discoidins, and methylmalonyl semialdehyde dehydrogenase (mmsdh), which we previously identified in genetic suppressor screens, providing greater evidence for their function in the network. Using the contractility controller as a model, we are identifying a quantitative interaction map, complete with new interactions, that is uncovering new biochemistry associated with the mechanobiome.

Contractility kits promote assembly of the mechanoresponsive cytoskeletal network.

Cellular contractility is governed by a control system of proteins that integrates internal and external cues to drive diverse shape change processes. This contractility controller includes myosin II motors, actin crosslinkers and protein scaffolds, which exhibit robust and cooperative mechanoaccumulation. However, the biochemical interactions and feedback mechanisms that drive the controller remain unknown. Here, we use a proteomics approach to identify direct interactors of two key nodes of the contractility controller in the social amoeba Dictyostelium discoideum: the actin crosslinker cortexillin I and the scaffolding protein IQGAP2. We highlight several unexpected proteins that suggest feedback from metabolic and RNA-binding proteins on the contractility controller. Quantitative in vivo biochemical measurements reveal direct interactions between myosin II and cortexillin I, which form the core mechanosensor. Furthermore, IQGAP1 negatively regulates mechanoresponsiveness by competing with IQGAP2 for binding the myosin II-cortexillin I complex. These myosin II-cortexillin I-IQGAP2 complexes are pre-assembled into higher-order mechanoresponsive contractility kits (MCKs) that are poised to integrate into the cortex upon diffusional encounter coincident with mechanical inputs.This article has an associated First Person interview with the first author of the paper.

Investigation on flow forming process using Taguchi-based grey relational analysis (GRA) through experiments and finite element analysis (FEA)

Flow forming is the shape change process which is used to manufacture high-precision seamless products for defense, aerospace and aviation industries. The tooling design in flow forming has vital importance in terms of online forces measurement and monitoring for desired output. Further, power consumption during the operation can be helpful to optimize the energy utilization. Moreover, the formability is always a great concern in metal forming processes. Hence, an attempt is made to investigate forces, power consumption and formability using Taguchi L36 mixed design. The analysis is performed using experiments and finite element analysis. Three levels of three operating parameters (i.e., speed, feed and reduction percentage) and two levels of two roller shape parameters (i.e., roller leading/attack angle and nose radius) are considered. It is observed that reduction percentage, roller attack angle, roller nose radius are the major factors which influence the resultant force. The power consumption is mainly influenced by speed and feed. The reduction percentage and depth of forming are the governing factors for the formability. Further, the multi-performance optimization is carried using grey relational analysis. The results between experiments and finite element analysis are compared and found to be in good agreement.