bluuebunny/crossref_metadata_2025 huggingface dataset:
Grading of oligodendroglioma in dogs based on magnetic resonance imaging
Authors: Amphimaque Bénédicte , Durand Alexane , Oevermann Anna , Vidondo Beatriz , Schweizer Daniela
Published: November 2022

Background

Oligodendroglioma (OG) accounts for 22% of primary brain tumors in dogs. Oligodendroglioma in dogs is graded as low‐grade (II) or high‐grade (III), based on the presence of microvascular proliferation and necrosis.

Objective

To investigate if magnetic resonance imaging (MRI) features differ between OG II and III in dogs.

Animals

Thirty‐two dogs with histological diagnosis of intracranial OG and MRI.

Methods

Retrospective descriptive study. Histology was reviewed to grade OG according to the revised classification. Brain MRI results were reviewed following criteria including contrast enhancement (CE) pattern, presence of cystic structures, gradient‐recalled‐echo (GRE) signal voids, and necrosis based on signal intensity, as well as diffusion‐weighted imaging characteristics. The MRI features were compared between OG II and III using Fisher's exact tests and logistic regression models.

Results

Histology identified 8 dogs with OG II (25%) and 24 with OG III (75%). All OG III showed moderate‐to‐marked CE including 18/24 (75%) with a ring pattern. These features were not seen in OG II. Heterogeneity, cystic structures, GRE signal voids, and necrosis were associated with OG III. No difference in diffusion characteristics was detected between OG II and III.

Conclusion and Clinical Importance

Moderate‐to‐marked CE and ring pattern were present in dogs with OG III but not in OG II. The presence of cystic structures, GRE signal voids, and necrosis was strongly associated with OG III. Although the importance of brain tumor grading in dogs with regard to prognosis and treatment options remains unknown, the results indicate that MRI reflects the histological features used for grading OG in dogs.
Low iron ameliorates the salinity‐induced growth cessation of seminal roots in wheat seedlings
Authors: Hua Ying‐peng , Zhang Yi‐fan , Zhang Tian‐yu , Chen Jun‐fan , Song Hai‐li , Wu Peng‐jia , Yue Cai‐peng , Huang Jin‐yong , Feng Ying‐na , Zhou Ting
Published: November 2022

Wheat plants are ubiquitously simultaneously exposed to salinity and limited iron availability caused by soil saline‐alkalisation. Through this study, we found that both low Fe and NaCl severely inhibited the growth of seminal roots in wheat seedlings; however, sufficient Fe caused greater growth cessation of seminal roots than low Fe under salt stress. Low Fe improved the root meristematic division activity, not altering the mature cell sizes compared with sufficient Fe under salt stress. Foliar Fe spray and split‐root experiments showed that low Fe‐alleviating the salinity‐induced growth cessation of seminal roots was dependent on local low Fe signals in the roots. Ionomics combined with TEM/X‐ray few differences in the root Na+ uptake and vacuolar Na+ sequestration between two Fe levels under salt stress. Phytohormone profiling and metabolomics revealed salinity‐induced overaccumulation of ACC/ethylene and tryptophan/auxin in the roots under sufficient Fe than under low Fe. Differential gene expression, pharmacological inhibitor addition and the root growth performance of transgenic wheat plants revealed that the rootward auxin efflux and was responsible for the low Fe‐mediated amelioration of the salinity‐induced growth cessation of seminal roots. Our findings will provide novel insights into the modulation of crop root growth under salt stress.
An instrumentalist explanation of pragmatic encroachment
Authors: Steglich‐Petersen Asbjørn
Published: November 2022

Many have found it plausible that practical circumstances can affect whether someone is in a position to know or rationally believe a proposition. For example, whether it is rational for a person to believe that the bank will be open tomorrow can depend not only on the person's evidence but also on how practically important it is for the person not to be wrong about the bank being open tomorrow. This supposed phenomenon is known as “pragmatic encroachment” on knowledge and rational belief. Assuming that the phenomenon is real, I ask what explains it. I argue that a variant of instrumentalism about epistemic reasons offers a natural explanation, that at the same time is able avoid commitment to a more radical form of pragmatism.
Application of haematology parameters for health management in fish farms
Authors: Chen Huijie , Luo Daji
Published: November 2022

Farmed fish are a promising source of high‐quality and sustainable protein. However, the production of farmed fish products that meet food safety standards is one of the major public health challenges worldwide. Therefore, food safety management in fish farms has recently garnered increasing attention. However, the detection of health parameters in fish is currently lacking. Haematology, an approach that is widely used in humans, provides a reliable assessment of health status in a non‐lethal and low‐cost way. Nevertheless, comprehensive, systemic and standard haematological parameters have not yet been established in farmed fish. Here, we provide a summary of the recent advancements in haematology health indicators in fish. Generally, haematological parameters are based on physiological and biochemical indices in blood. After a global review of haematology in fish, we analysed the research progress and current trends in haematology indicators in farmed fish, and explored their potential application for healthy farming. Furthermore, we discuss the internal and external environmental factors that also affect blood physiological and biochemical indices. Finally, we discuss the trends and future challenges for the application of haematology in fish. Collectively, the topics discussed in this review highlight the predictive and severely underrated value of haematological parameters in fish farming.
Intraoral approach for zygomatic sialoadenectomy in dogs: An anatomical study and three clinical cases
Authors: Viitanen Joni , de Rooster Hilde , Kitshoff Adriaan , Arzi Boaz , Devriendt Nausikaa
Published: November 2022

Objective

To describe an intraoral approach (IOA) for zygomatic sialadenectomy in dogs and to compare this surgical approach to a modified lateral orbitotomy approach (LOA).

Study design

Cadaveric study and short case series.

Sample population

Ten canine cadavers and three dogs with clinical disease.

Methods

Bilateral zygomatic sialoadenectomies were performed in six mesocephalic, two brachycephalic and two dolichocephalic cadavers, randomly assigned to IOA on one side and LOA on the contralateral side. Duration of surgery, ease of surgical stage scores (rated on 5‐point Likert scale) and completeness of gland removal were recorded. Additionally, IOA was performed in three dogs with zygomatic salivary gland (ZSG) disease.

Results

Removal of the ZSG was complete in 8/10 and 10/10 dogs using the IOA and LOA, respectively. Surgery was faster with IOA (42.0 min; 33.5–49.6 min) than LOA (65.7 min; 54.9–76.4 min, p = .005). Ease of removal did not differ between approaches (p = .091). Diseased ZSGs were successfully removed in three dogs without intra‐ or short‐term postoperative complications.

Conclusions

The intraoral approach described here was technically equally challenging but faster than the LOA. Its clinical use led to an uneventful surgery with excellent short‐term outcome in three dogs.

Clinical relevance

The IOA provides an alternative approach for zygomatic sialoadenectomy in dogs with ZSG disease.
Numerical Simulation of Hit Noise Generation Due to Sloshing Phenomenon in a Rectangular Tank Under Periodic Excitation
Authors: Golla Siva Teja , Jadhav Atul R. , Banerjee Raja , Venkatesham B.
Published: November 2022

Sloshing in fuel tanks is one of the major sources of noise in hybrid and high-end vehicles. During sloshing, the fluid causes impacts on tank walls resulting in their vibration, which further leads to noise, referred to as “hit noise.” Therefore, hit noise generation is a multi-physics phenomenon involving fluid flow, structural response, and acoustic radiation. This paper presents a multi-physics approach to predict hit noise in a rectangular tank. The methodology involves the prediction of fluid loading on tank walls and their structural response using transient fluid and structural analyses which are weakly coupled. Radiated hit noise is predicted using acoustic finite element analysis. Longitudinal periodic excitation is applied to the fluid domain at different frequencies to simulate the sloshing regime which has dominant fluid–structure interactions. Parameters like tank wall pressures, the resulting dynamic acceleration, and radiated sound pressure levels are monitored and validated with the experimental results available in the literature.
Thermodynamic Performance Analysis of Conductive Cylindrical Funnel With Surface Radiation in an Infrared Suppression Device
Authors: Mukherjee Arnab , Chandrakar Vikrant , Senapati Jnana Ranjan
Published: November 2022

The current research looks at the thermodynamic performance analysis of an infrared suppression (IRS) system for warships, battleships, and ocean liners. ansys fluent 15.0 is used to solve governing differential equations (Navier–Stokes equation, energy equation, and equation of turbulence). The results are then used to produce a more detailed and accurate system model. Relevant parameters vary, such as the Reynolds number (6.12 × 105 to 3.11 × 106), louver pattern, the temperature of the nozzle inlet (400–600 K), and the different types of shapes of the nozzle. The effects of nozzle exhaust fluid temperature and different funnel wall conditions (adiabatic, diabatic with and without surface radiation) on heat transfer and entropy production are considered in various quantities. The entropy generation study helps justify the proposed design of the IRS system and select the best model among the proposed designs. Both the thermal and frictional irreversibility are plotted along with the Bejan number plots and the entropy generation contours to elucidate the thermofluid behavior.
Friction of Coated and Uncoated Rough Surfaces in Additive-Free and Fully Formulated Engine Oils Under Boundary and Mixed Lubrication Conditions
Authors: Liu Zhiqiang , Yin Jiandong , Zhao Fucheng
Published: November 2022

Downsizing in spark-ignited engines becomes one of the most effective concepts to achieve fuel economy and emissions requirements and drives operating conditions of major moving engine components into more mixed and boundary lubrication regimes. Piston ring design faces considerable challenge to reduce friction losses, oil consumption, blow-by, and wear. Surface coatings have received great attention in applications of automotive engine components due to their unique friction properties. In this study, an elastic–plastic contact model of rough surfaces with hard coatings is used to provide proper design of the ring coating thickness concerning the plasticity-yielding resistance of stiff coating. A diamond-like carbon (DLC) coating with surface hardness higher than current production ring coatings has been evaluated in additive-free base oil and fully formulated engine oil under boundary and mixed lubrication conditions. The friction behavior of the coated material relative to uncoated materials is compared in boundary and mixed lubrication regimes. A traction-merging rolling speed in the mixed lubrication regime is observed, at which friction coefficient is independent of applied loads. By using a mixed lubrication model previously published, calculations indicate that the lower the traction-merging rolling speed, the earlier the contact approaches elastohydrodynamic lubrication (EHL), therefore reducing the risk of asperity-interacting fatigue in boundary and mixed lubrication regimes. Effects of tribofilm on friction behavior for DLC coating and uncoated steel in fully formulated oil are investigated by using measured Stribeck curves in conjunction with the model. The results from this study analytically support one of the possible mechanisms of tribofilm-dependent friction enhancement in mixed lubrication conditions proposed in the earlier publication.
Effects of Heat Treatment on Sliding Wear and Milling Properties of Ti-6Al-4V Prepared by Selective Laser Melting
Authors: Zhang Bo , Wang Zhen-Hua
Published: November 2022

Ti-6Al-4V titanium alloy manufactured by selective laser melting (SLM) has a unique structure and properties. They offer a higher yield and ultimate tensile strengths but lower ductility than traditionally processed samples. SLMed Ti-6Al-4V alloys induced increased ductility but decreased tensile strengths after thermal treatment at 840 °C for 2 h. Sliding wearing tests and cutting experiments were conducted to further understand the effects of heat treatment on machinability. The results showed that as-built SLMed Ti-6Al-4V samples presented lower coefficients of friction but higher wear-rates than heat-treated ones due to their delamination caused by cracks. Cutting forces of as-built samples were lower during milling than that of heat-treated samples. Nevertheless, better surface roughness was produced when heat-treated samples were machined. Moreover, the optimal cutting parameters for both materials were the same.
What Do We Mean When We Write About Ethics, Equity, and Justice in Engineering Design?
Authors: Das Madhurima , Roeder Gillian , Ostrowski Anastasia K. , Yang Maria C. , Verma Aditi
Published: November 2022

Engineering design often requires engaging with users, clients, and stakeholders of products and systems. It is therefore important for designers to reflect on the societal and environmental implications of their design work so that they can design equitably, ethically, and justly. We conduct a review of three leading scholarly engineering design venues to investigate how, when, and why these terms — “ethics,” “equity,” and “justice,” and variations — appear in the engineering design literature and what scholars mean when they use them. We find that these terms are minimally present within the field’s scholarship and posit that design researchers may be using other terms to refer to their work that is aligned with principles of ethics, equity, and justice. We find that the prevalence of these terms has increased over time and that the terms come up throughout various stages of the design process. There appear to be a variety of motivations for including these terms, notably, sustainability and education of the next generation of designers. Finally, we propose an expanded design justice framework that is specific to engineering design. We encourage designers in our field to adopt this framework to assist them in thinking through how their engineering design work can be used to advance justice.
A Study of the Exploratory Creativity Performance Between Machine and Human Designers
Authors: Yin Yuan , Qin Kaitong , Liu Huiting , Childs Peter , Sun Lingyun , Chen Liuqing
Published: November 2022

Exploratory creativity (E-creativity) is used to represent the creative performance behind the exploration process when establishing conceptual space. Researchers have attempted to build computational E-creativity models to help human generate more creative ideas or solutions. This trend sparks the discussion on whether the performance of machine can achieve a similar level to human beings. However, the performance gap of E-creativity between human beings and machine has not been fully studied. This study aims to investigate the E-creativity performance differences between machine and human designers. To be specific, a state-of-the-art model DALL·E is chosen as a representative of machines for generating E-creativity imagery and is compared to novice designers who are the representative for generating E-creativity imagery of humans. Expert designers are recruited as assessors to assess the creativity and E-creativity performance of the collected human and machine data. The experimental results reveal that the creativity level of humans is higher than that of machine. The E-creativity level of machine is higher than that of humans. The textual E-creativity performance is higher than the imagery E-creativity performance of humans while it is lower than the imagery E-creativity performance of machine. The results provide insights for supporting the development of more advanced E-creativity engines and corresponding evaluation methods.
t-METASET: Task-Aware Generation of Metamaterial Datasets by Diversity-Based Active Learning
Authors: Lee Doksoo , Chan Yu-Chin , Chen Wei (Wayne) , Wang Liwei , Chen Wei
Published: November 2022

Inspired by the recent achievements of machine learning in diverse domains, data-driven metamaterials design has emerged as a compelling paradigm that can unlock the potential of the multiscale architectures. The model-centric research trend, however, lacks principled frameworks dedicated to data acquisition, whose quality propagates into the downstream tasks. Built by naive space-filling design in shape descriptor space, metamaterial datasets suffer from property distributions that are either highly imbalanced or at odds with design tasks of interest. To this end, we present t-METASET: an active-learning-based data acquisition framework aiming to guide both balanced and task-aware data generation. Uniquely, we seek a solution to a commonplace yet frequently overlooked scenario at early stages of data-driven design: when a massive shape-only library has been prepared with no properties evaluated. The key idea is to harness a data-driven shape descriptor learned from generative models, fit a sparse regressor as a start-up agent, and leverage metrics related to diversity to drive data acquisition to areas that help designers fulfill design goals. We validate the proposed framework in three deployment cases, which encompass general use, task-specific use, and tailorable use. Two large-scale mechanical metamaterial datasets (∼ O(104)) are used to demonstrate the efficacy. Applicable to general design representations, t-METASET can boost future advancements in data-driven design.
Uncertainty Quantification of Physics-Based Label-Free Deep Learning and Probabilistic Prediction of Extreme Events
Authors: Li Huiru , Yin Jianhua , Du Xiaoping
Published: November 2022

Surrogate models from machine learning regression have been increasingly used in engineering analysis and design. Since surrogate models are usually built using data from solving expensive physical models, label-free machine learning methodologies have been developed to reduce the computational cost. Understanding and quantifying the model (epistemic) uncertainty of surrogate models is critical for their applications with quantified confidence. It is, however, much more computationally expensive, or even impossible to quantifying the model uncertainty for label-free machine learning. In this work we propose an uncertainty quantification method for the epistemic uncertainty of physics-based label-free regression. The method is used after a surrogate model has already been built by deep neural network based on the data of only input variables without labels (data of responses) and a system of physical equations. A surrogate model of the neural network regression model error is built with Gaussian Process regression using the existing training points and the derivatives of the system of physical equations at the training points. The error model is then used to compensate the error of the neural network surrogate model, therefore producing more accurate predictions. With higher accuracy, the proposed method is applied to probabilistic prediction of extreme events where both (aleatory) data uncertainty and model uncertainty coexist, and higher accuracy is required. Its application to time-dependent reliability prediction of a four-bar linkage mechanism demonstrates the high accuracy of the proposed method.
Concreate: Using Data Physicalization to Increase The Understanding and Inspirational Use of Quantitative Data In Data-Driven Design Scenarios
Authors: Spalburg Tiara , Chandrasegaran Senthil , Eikelenberg Nicole , Gonçalves Milene
Published: November 2022

In today’s world, the advantages of data-enabled design are undeniable, increasing the performance of organisations drastically by informing and inspiring the design process. While organisations seem to be more experienced with quantitative data for evaluative purposes, they do struggle to use data as creative material to inspire the design process. Choosing the right type of data representation is critical for using data for creative purposes. Data visualization has proven to be highly effective in increasing understanding of data, as it is fast, accurate and flexible. Data physicalization, on the other hand, remains unexplored in comparison, especially its effect on creativity. This paper presents the results of two studies (one preliminary and one follow-up study), which explored the use of data physicalization in creative settings. The preliminary study enabled to collect initial requirements for the development of a physicalization toolkit, while the follow-up study investigated its impact on the design process, in comparison to data visualization. From the studies, we developed Concreate, a collaborative data physicalization toolkit designed to lead to creative insights from quantitative data. Our results show that Concreate can potentially stimulate creative thinking, by encouraging intense, tangible interaction with data leading to increased reflection-in-action and a deeper understanding of data. The two studies and toolkit development were carried out at a multinational automotive company, interested in innovating by incorporating data as creative material. Besides the immediate practical implications, we conclude this paper with a discussion on future recommendations for using data physicalization in the design process.
Facial Expression Recognition as a Measure of User-Designer Empathy
Authors: Salmi Aleksi , Li Jie , Holtta-Otto Katja
Published: November 2022

In human-centered product design and development, understanding the users is essential. Empathizing with the user can help designers to gain deeper insights into the user experience and their needs. However, capturing real time empathy during user interaction and the degree to which empathy enhances user understanding remains unclear. To narrow this gap, this study aims to explore the use of facial expression recognition during a videotaped user interview as means to capture empathy. Mimicry and synchrony have been shown to be predictors of empathy in cognitive psychology. In this study, we adapt this method to 46 user-designer interviews. The results show that the user and designer show mimicry in their facial expressions, which indicates that affective empathy can be captured via facial recognition. However, we find that the user’s facial expressions might not represent their actual emotional tone, which can mislead the designer. Further, we do not find a link between the observed mimicry of facial expressions and the understanding of mental contents, which hints that the affective and some cognitive parts of user empathy may not be directly connected. Further studies are needed to understand how facial expression analysis can further be used to study and advance empathic design.
Modeling and Analysis of Uncertain Static Contact Characteristics for Revolute Clearance Joints
Authors: Liu Sheng , Yu Haidong , Gu Bin , Zhao Yong
Published: November 2022

The presence of uncertain clearance in revolute joints affects the motion accuracy and stability of the mechanical system with revolute joints. In this paper, a novel static conformal contact force (CCF) model for revolute clearance joints is developed to evaluate the relationship between contact forces and penetration depth in conformal contact problems based on the geometric constraints and the Winkler elastic foundation theory. Compared to the other two conventional static contact force models, the computational results of the proposed CCF model are more consistent with the FEM simulation results in analyzing the conformal contact problems. Static contact characteristics of the revolute joint during conformal contact are investigated using the established CCF model when considering the fuzzy uncertainty of clearance size and material parameters of the joint. The analysis results may be used to guide the design and the contact analysis of the revolute clearance joints.
Stability of Rotorcraft Ground Resonance by Estimating Lyapunov Characteristic Exponents From Multibody Dynamics
Authors: Cassoni Gianni , Zanoni Andrea , Tamer Aykut , Masarati Pierangelo
Published: November 2022

This work discusses the use of Lyapunov Characteristic Exponents to assess the stability of nonlinear, time-dependent mechanical systems. Specific attention is dedicated to methods capable of estimating the largest exponent without requiring the Jacobian matrix of the problem, which can be applied to time histories resulting from existing multibody solvers. Helicopter ground resonance is analyzed. Improvements over the available literature are: the problem is formulated in physical coordinates, without eliminating periodicity through multiblade coordinates; the rotation of the blades is not linearized; the problem is modeled considering absolute positions and orientations of parts. The dynamic instability that arises at some angular velocities when the isotropy of the rotor is broken (e.g., caused by the failure of one lead-lag damper, a design test condition) is observed to evolve into a large amplitude limit cycle, where the usual Floquet-Lyapunov analysis of the linearized time-periodic simply predicts instability.
Kinematics of an Origami Inspired Millipede Robot
Authors: Liu Chenying , You Zhong , Maiolino Perla
Published: November 2022

A millipede is a worm-like arthropod with a relatively hard exoskeleton, a segmented body, and numerous pairs of legs. Its appendage helps to coordinate the behaviour of multiple body segments to generate a peristaltic wave, so that efficient locomotion can be achieved on uneven surfaces and limited space. When sensing danger or disturbed, the millipede curls up into a coil shape to protect itself against predators. The curling behaviour of a millipede has also been found in some of its close relatives in the arthropod family, such as pill bugs and lobsters. Inspired by its peristaltic and curling behaviours, we propose an origami-based concept for a robot that imitates the motion of a millipede. The mechanism is made with a chain of interlinked modules, mimicking the segments in a millipede. Each module is an assembly of rigid facets with a uniform and finite thickness, reducing the overall degrees of freedom (DoF) to a manageable number. Given its unique geometric design, the assembly can contain any number of modules without an excessively large DoF. Its curling and peristaltic motions are quantified kinematically in the paper, which paves the way for the millipede robot design with actuation and control components integrated. In addition, a few other configurations of the proposed origami mechanism and its geometric variants are presented, thus opening up design space for other possible applications.
Stress Trajectory Guided Structural Design and Topology Optimization
Authors: Wang Junpeng , Wu Jun , Westermann Rüdiger
Published: November 2022

Density-based topology optimization using global and local volume constraints is a key technique to automatically design lightweight structures. It is known that stiffness optimal structures comprise spatially varying geometric patterns that span multiple length scales. However, both variants of topology optimization have challenges to efficiently converge to such a structural layout. In this paper, we investigate material layouts that are generated from stress trajectories, i.e., to compile a globally consistent structure by tracing the stress trajectories from finite element simulation of the solid design domain under external loads. This is particularly appealing from a computational perspective, since it avoids iterative optimization that involves finite element analysis on fine meshes. By regularizing the thickness of each trajectory using derived strain energy measures along them, stiff structural layouts can be generated in a highly efficient way. We then shed light on the use of the resulting structures as initial density fields in density-based topology optimization, i.e., to generate an initial density field that is then further optimized via topology optimization. We demonstrate that by using a stress trajectory guided density initialization in lieu of a uniform density field, convergence issues in density-based topology optimization can be significantly relaxed at comparable stiffness of the resulting structural layouts.
On the Effect of Nonlinear Energy Sink Damping in Seismic Vibration Attenuation
Authors: Motato Eliot , Guerrero Fabio
Published: November 2022

Nonlinear Energy Sinks (NES) are passive vibration absorbers composed of a small inertia and a smooth nonlinear stiffness with linear viscous damping. The main advantage of a NES is its lack of preferential natural frequency, then NESs can resonate over a wide range of frequencies and with any mode of the primary structure to which they are connected. These kind of absorbers however, are energy-dependent devices limited by energy thresholds where optimal design regions can be very close to low effective ones. It is then frequent that changes in the exciting energy levels can significantly reduce the performance of previously tuned NESs. The NES energy sensibility, limit its capabilities to control vibrations in structures subject to seismic induced excitations. Preliminary studies have shown that this sensitivity can be reduced by properly tuning the NES damping but no formal procedure exist. In this work we present a numerical methodology to tune the NES parameters by defining an index that quantifies the effect that NES damping has on the absorber robustness. A three-story shear building model subject to random seismic ground excitation is used to introduce the concepts and the methodology.
Extending and Bending Robotic Limbs Using Tape Springs for Mobility and Manipulation: Preliminary Investigations
Authors: Quan Justin , Hong Dennis
Published: November 2022

Conventional mobile robots have difficulty navigating highly unstructured spaces such as caves. In these environments, an extendable/retractable mechanism could be useful for deploying hooks to climb over terrain, or for reaching hard-to-access sites for sample collection. Spooled tape spring mechanisms offer long reach in a compact package, but have not been widely explored for use in mobility and manipulation tasks. This paper proposes a new form of multimodal mobile robot that utilizes a novel tape spring limb named EEMMMa (Elastic Extending Mechanism for Mobility and Manipulation). For mobility, the limb can extend prismatically to deploy grappling hook anchors to suspend and transport the main body, or even serve as legs. For manipulation, the limb can morph its shape to bend around or over obstacles and extend to reach into tight spaces. This can allow the limb to retrieve distant objects, position cameras around corners, or place grappling anchors above an overhang such as a table or cliff. The EEMMMa-1 prototype detailed in this paper can climb ladders and shelves, and exhibit shape morphing to bend over obstacles. The extendable limb uses a simple braking function as a mechanical multiplexer, which can change the limb’s kinematics to control a second rotational DOF using only a single motor. The paper concludes by detailing potential applications and configurations of future EEMMMa robotic systems.
Incorporating Performance Portability and Data-Oriented Design in Phase-Field Modeling
Authors: Yenusah Caleb , Stone Tonya W. , Morgan Nathaniel R. , Robey Robert W. , Liu Yucheng , Chen Lei
Published: November 2022

The advancements in modern computer architecture have made it possible for the simulation of large-scale problems that are of industrial application. However, it can be time-intensive to continually port scientific codes to the ever-evolving computer architectures. Therefore, it is important to develop computational tools that make it easy for researchers to port their existing scientific software or develop new software that can run optimally on current and future computer architectures from different vendors. Also, it often advantageous for scientific software to leverage fine-grained parallelism on homogeneous architectures that are comprised of multi-core CPUs and on heterogeneous computer architectures comprised of multi-core CPUs and GPUs. This paper demonstrates the incorporation of performance portability and data-oriented design paradigms in the phase-field modeling of microstructure evolution. To achieve this, we utilized MATAR, a C+ + software library that allows the straightforward creation and usage of multidimensional and multi-size dense or sparse matrix and array data structures that are also portable across disparate architectures using Kokkos. As a case study, we use the phase-field model for spinodal decomposition which numerically solves the Cahn-Hilliard equation using the semi-implicit Fourier spectral method. Performance portability across multi-core CPUs and different GPU architectures are investigated. Additionally, numerical accuracy and performance gains between single and double precision phase-field calculations are investigated.
Origami-Inspired Closeouts for Starshade Inner Disk Optical Shields
Authors: Haraszti Alexandra , Arya Manan
Published: November 2022

A starshade is a concept for a deployable external occulter to a telescope that enables the imaging of exoplanets by blocking out the light of the host star. The starshade architecture has an inner disk structure consisting of a lightweight opacity blanket and a stiff perimeter truss. The opacity blanket is called the optical shield and folds with an origami-inspired spiral wrapping pattern. The inner disk architecture has a physical gap: there is a difference in geometry between the perimeter truss and optical shield in both the stowed and deployed configurations. To demonstrate the deployment of the starshade inner disk at a higher level of fidelity, an opaque closeout must be developed to span the difference in geometric shape. Here we describe the design of an origami-motivated closeout design for the optical shield. We propose several closeout fold patterns, for which we optimized the difference in normalized fold line lengths between the folded and unfolded states to be less than 0.01%. The close-out patterns are then validated by simulation and prototyping. These patterns may be realized with flight-like materials and will enable the technological maturation of the starshade concept.
Anisotropic Approach to Control Viscous Fingering Pattern Generated in Lifting Plate Hele-Shaw Cell
Authors: Bhole Kiran S. , Kale Bharatbhushan S. , Mastud Sachin , Raykar Nilesh , Sharma Chetna , Deshmukh Prashant
Published: November 2022

Stability is one of the important aspects of life, our everyday systems — the permanence of things. When this stability gets disturbed, instability is produced. Sometimes this instability is desirable, and sometimes not. In the crude oil extraction process, fluid instability is observed. Saffman and Taylor explored the concept of the Hele-Shaw cell to study these instabilities. The Hele-Shaw cell involves a high viscous fluid sandwiched between two parallel plates, and the low viscosity fluid enters from the periphery. Insertion of low viscous fluid into a high viscous fluid generates a pattern that is a resemblance to a finger. This phenomenon is called viscous fingering. In this paper, the authors control the instabilities and mimic patterns available in nature. These instabilities can be controlled by controlling one of the fluids in the cell. Here authors control the low viscous fluid (air) by providing anisotropies. Anisotropy means providing holes and slots on any plate of the cell. This anisotropy guides air to interact with high viscous fluid at some desired location. The authors further studied the effect of size, position, the orientation of these holes and slots on the viscous fingering exhaustively.
Trust in Human-Robot Interaction Within Healthcare Services: A Review Study
Authors: Townsend Dedra , MajidiRad AmirHossein
Published: November 2022

There has always been a dilemma of the extent to which human can rely on machines in different activities of daily living. Ranging from riding on a self-driving car to having an iRobot vacuum clean the living room. However, when it comes to healthcare settings where robots are intended to work next to human, making decision gets difficult because repercussions may jeopardize people’s life. That has led scientists and engineers to take one step back and think out of the box. Having concept of trust under scrutiny, this study helps deciphering complex human-robot interaction (HRI) attributes. Screening essential constituents of what shapes the trust in human mind as s/he is working with a robot will provide a more in-depth insight through how to build and consolidate the trust. In physiotherapeutic realm, this feeds into improving safety protocols and level of comfort; as well as increasing the efficacy of robot-assisted physical therapy and rehabilitation. This paper provides a comprehensive framework for measuring trust through introducing several scenarios that are prevalent in rehabilitation environment. This proposed framework highlights importance of clear communication between physicians and how they expect robot to intervene in a human centered task. In addition, it reflects on patients’ perception of robot assistance. Ultimately, recommendations are made in order to maximize trust earned from the patients which then feeds into enhancing efficacy of the therapy. This is an ongoing study; authors are working with a local hospital to implement the know in a real-world application.
Nonlinear Energy Sink and Targeted Energy Transfer in Smart Structures
Authors: Dekemele Kevin , Van Torre Patrick , Loccufier Mia
Published: November 2022

Nonlinear energy sinks (NESs) are strongly nonlinear mechanical oscillators that are weakly coupled to a mechanical primary system. Through targeted energy transfer (TET), vibration energy is irreversibly transferred from the primary system to the NES, making the NES an attractive passive vibration control device. Furthermore, because of the NES’ strong nonlinearity, the NES has a variable natural frequency, unlike linear vibration control devices. This enables a self-tuning property where the NES adapts to the primary system’s vibration frequency, making the NES a broadband vibration absorber. This self-tuning extends to multi-frequency vibrations through resonance capture cascade (RCC), where the NES tunes itself to the different frequencies in sequential order. Recently, some works have discussed the piezoelectric NES, a nonlinear electrical circuit that interfaces with a mechanical system through a piezoelectric transducer. This paper will show for the first time that by using an electromagnetic transducer instead of a piezoelectrical transducer, an electromagnetic NES is obtained. Furthermore, this work will show that dynamics of mechanical, piezoelectric and electromagnetic NESs can be generalized under a universal NES in a slow flow expression and that resonance capture cascade occurs for all the NES types. The performance of the NES configurations are compared and their physical components are discussed.
Modeling Large Deformable Terrain With Material Point Method for Off-Road Mobility Simulation
Authors: Chen Guanchu , Yamashita Hiroki , Sugiyama Hiroyuki , Ruan Yeefeng , Jayakumar Paramsothy , Gorsich David , Leiter Kenneth W. , Knap Jaroslaw , Yang Xiaobo
Published: November 2022

In this study, a computational framework for the material point method (MPM) terrain model is developed for off-road mobility simulations to account for large granular terrain deformation in high-fidelity off-road mobility simulations. The Lagrangian finite element (FE) approach is not suited for modeling very large soil deformation due to mesh distortion, which causes element instability. Whereas the discrete element (DE) approach has gained acceptance in modeling complex granular material behavior, the computational cost is, in general, prohibitively high due to a large number of particles needed to describe not only the grain-scale material behavior, but also the macro-scale large soil deformation. Therefore, this study examines the use of MPM to model large deformable granular terrain in the context of off-road mobility prediction. To this end, MPM terrain models are developed and integrated into the off-road mobility simulation framework, leveraging high-performance computing. Furthermore, a contact modeling procedure for the FE tire and MPM terrain is developed, along with the moving soil patch technique generalized for the MPM terrain with the background grid. The MPM soil model is validated against test data, and its large deformation modeling capabilities are examined with several numerical examples.
Flexible Multibody Model of a Complete Tiltrotor for Aeroservoelastic Analysis
Authors: Cocco Alessandro , Savino Alberto , Masarati Pierangelo
Published: November 2022

This work presents a numerical validation and capability demonstration of the solver MBDyn when applied to a complex tiltrotor model. The Bell XV-15 tiltrotor equipped with Advanced Technology Blades (ATB) is chosen since a considerable amount of data is publicly available. The multibody modeling of each sub-component, i.e. the rotor, blades, yoke, drive system, and the airframe is illustrated and validated considering experimental and numerical results. This work is a first step towards further, more complex analyses, such as whirl-flutter stability assessment, transient maneuvers, and pilot-vehicle interaction.
Self-Aligning Rotational Latching Mechanisms
Authors: Fernandez Gabriel I. , Gessow Samuel , Quan Justin , Hong Dennis
Published: November 2022

In concurrent work, we introduced a novel robotic package delivery system LIMMS (Latching Intelligent Modular Mobility System). Each of LIMMS’ end effectors requires a small, lightweight latching mechanism for pre-manufactured containers such as cardboard boxes. In order to effectively process a high volume of packages, aligning the latching mechanism quickly and reliably becomes critical. Instead of depending on highly accurate controllers for alignment, we propose a novel self-aligning rotational mechanism to increase the system’s tolerance to misalignment. The latching design consists of evenly spaced blades that rotate into slots cut into the box. When misaligned, the blades contact the edges of the engagement slots, generating a self-correcting force that passively centers the blades with the slot pattern. This paper introduces a mathematical framework with closed form expressions to quantify error tolerance for for these mechanisms. Through our mathematical and optimization analyses, it is shown that a 2-blade design can tolerate a maximum misalignment: 5 ≈ 2.236 times the radius of the blade tips. Our approach can be generalized for a class of rotational latching mechanisms with any number of blades. Utilizing this theory, a design process is laid out for developing an optimal self-aligning rotational latching mechanism given desired parameters and task constraints. With this methodology, we designed, manufactured, and verified the effectiveness of both 2-blade and 3-blade self-aligning latches in practical experiments.
Disassembly Analysis of Gas Cooktops: Towards Eco-Design Rules for Product Repairability
Authors: Boix Rodríguez Núria , Favi Claudio
Published: November 2022

The ease of disassembly and the application of repairability metrics are important in determining the ability to repair industrial products and goods (e.g., ease of Disassembly Method, Repair Scoring System, French repairability index, etc.). Increasing product repairability is a key aspect to tackle during the product development process aiming at the product lifetime extension and the reduction of industrial waste. The purpose of this work is to find eco-design actions by examining the ability to disassemble key components in different types of gas hobs. After the definition of target components, several disassembly tests were performed following the method proposed by the Joint Research Centre’s report (Analysis and development of a scoring system for repair and upgrade of products) and the European standard EN 45554 (General methods for the assessment of the ability to repair, reuse and upgrade energy-related products). The Disassemblability Index of each priority part has been calculated, being able to verify that one of the factors that affect the most is the number of steps needed to remove the component. The outcomes offer interesting insights into the characterization of disassembly issues as well as for the identification of possible eco-design actions making the product repairability efficient and less costly.
Phononic Metamaterial Design via Transfer Learning-Based Topology Optimization Framework
Authors: Wang Zihan , Zhuang Ran , Xian Weikang , Tian Jiawei , Li Ying , Chen Shikui , Xu Hongyi
Published: November 2022

Phononic metamaterials are widely used to attenuate wave propagation. However, designing the structure of phononic metamaterial remains a challenge. In this work, we proposed a transfer learning-based design framework to accelerate the design of phononic metamaterials with wide bandgaps. First, we establish a transfer learning model with convolutional layers. This model leverages the knowledge learned from the structure-elasticity dataset to predict the structure-phononic property relationship. We demonstrate that the transfer learning model achieves good prediction accuracy with limited training data. We also discuss the feasibility of using the structure-elasticity model to benefit the design optimization of phononic metamaterials. Then we propose a transfer learning-based design framework for the topology optimization of cellular metamaterial for optimal phononic properties (bandgap width). Parametric optimization is conducted to find the optimal structure features that lead to the widest bandgap. The structure features are represented by an embedding layer shared by the structure-elasticity and the structure-phononic property models. Next, the corresponding elastic stiffness constants are obtained via the structure-elasticity model. Then topology optimization is employed to generate the metamaterial structural images corresponding to the target elastic stiffness constant values. The effectiveness of the proposed design framework is validated by comparing the performances of design candidates with existing designs.