bluuebunny/crossref_metadata_2025 huggingface dataset:
Lateral‐pushing induced surface lift‐up during nanoindentation of silicate glass
Authors: Ding Linfeng , Xu Yanan , Yang Rui , Yang Yongjian , Lu Ranran , Liu Hao , He Hongtu , Zheng Qiuju , Mauro John C.
Published: December 2021

Shear flow and/or densification have been long considered as the main mechanisms accounting for inelastic deformation during indentation of silicate glasses. However, the role of inelastic deformation during indentation of silicate glass is still debated. In this work, the cube‐corner indenter was chosen to perform the nano‐indentation tests on four different types of silicate glasses with a penetration depth of up to 0.5 μm. A 3D surface analysis method is developed to quantify the amplitude of the impression field. Based on this newly developed analysis approach, we have found that the shear flow and densification induced inelastic deformation of silicate glasses are visible as indentation, as pile‐up close to the indent, and as lift‐up far away from the indent. The lift‐up mechanism is revealed for the first time, which complements the previous well‐accepted pile‐up description. The lift‐up region is due to the increasing width of the indenter as it is pushed into the glass, which corresponds to the amount of glass volume pushed away laterally (lateral‐pushing) and can contribute up to ∼25% of the total volume above the original surface in soda‐lime silicate glass. We believe that this better quantification of inelastic deformation will contribute to reveal the structural evolution during nano‐indentation of silicate glass.
Medial gastrocnemius growth in children who are typically developing: Can changes in muscle volume and length be accurately predicted from age?
Authors: Obst Steven , Florance Kaysie , Heales Luke , Barber Lee
Published: December 2021

Muscle size is an important determinant of muscular fitness and health, and so it is important to have accurate estimates of actual muscle growth in children. This study compared actual versus age‐predicted growth rates of the medial gastrocnemius (MG) muscle in young children over a 12‐month period. Three‐dimensional ultrasound was used to measure MG length and volume in 50 children (mean ± standard deviation [SD] age = 70.3 ± 29.9 months) to establish age‐predicted muscle growth rates using a least‐squares linear regression. Twenty children (mean ± SD age = 78.5 ± 27.2 months) were followed up at 6 and 12 months to establish actual muscle growth of MG volume and length. These data were then compared to their age‐predicted muscle growth from the linear regression equation using paired t‐tests and Bland–Altman limits of agreement method. Age‐predicted MG growth significantly underestimated actual muscle growth for both volume and length at each timepoint. On average, actual muscle volume and length were 11.5% and 21.5% greater than the age‐predicted volume and length respectively. Caution is warranted when predicting future muscle size in young children based solely on age.
Predictors of oral chemotherapy adherence at home among Chinese cancer patients: An observational prospective study
Authors: Chen Yongfeng , Zhang Liyuan , Wei Cuiling , Chen Fangfang , Bai Jinbing
Published: December 2021

Aims and Objectives

To explore whether medication non‐adherence experience, readiness for hospital discharge, financial toxicity and symptoms predicted oral chemotherapy adherence at home for Chinese cancer patients.

Background

Oral chemotherapy adherence is critical to determine the treatment efficacy among cancer patients. Identifying predictors before discharge from hospital based on transition theory could assist healthcare providers to improve oral chemotherapy adherence at home.

Design

An observational prospective study.

Methods

Between October 2018 and December 2019, self‐reported questionnaires were used to collect data among 151 cancer patients with oral chemotherapy at home. At discharge, baseline data of patient‐perceived readiness for hospital discharge, financial toxicity and non‐adherence experience were collected, while symptoms and adherence of oral chemotherapy at home were collected after finishing one cycle of oral chemotherapy at home (21 days, the first 14 days received oral chemotherapy). Regression analyses were performed for the predictors’ explorations. The STROBE guidelines were followed.

Results

Among 151 participants with oral chemotherapy at home, 30.46% of patients reported medication non‐adherence experience at discharge and 82.12% of patients reported adherence to oral chemotherapy at home. Patients with non‐adherence experience at discharge were 5.4 times more likely to being non‐adhered to oral chemotherapy at home. Numbness were the most frequent and severe symptoms during at home, patients with numbness were 6.6 times more likely to being non‐adhered to oral chemotherapy. Although patients reported high level of readiness for discharge and financial toxicity at discharge, which did not predicted oral chemotherapy adherence at home.

Conclusions

Patients with medication non‐adherence experience at discharge and symptom of numbness from oral chemotherapy suggested a higher risk of oral chemotherapy non‐adherence at home.

Relevance to clinical practice

Preventive interventions should focus on patients with previous medication non‐adherence experience at discharge and experiencing numbness to promote oral chemotherapy adherence.
Human white adipose tissue: A highly dynamic metabolic organ
Authors: Arner Peter , Rydén Mikael
Published: December 2021

Recent technological developments have allowed determination of the age of fat cells and their lipids in adult humans. In contrast to prior views, this has demonstrated a high turnover rate of the fat cells (10%/year) and their unilocular lipid droplets (six times/10 years). Fat cell turnover is increased in obesity and when adipose tissue is composed of many but small adipocytes (hyperplasia, a benign adipose phenotype). While fat mass gain increases adipocyte number and size, only the latter is altered (decreased) after weight loss, which may facilitate weight regain. Fat cell lipid turnover is attenuated in subjects with excess body fat. In the subcutaneous region, this dysregulation occurs already in the overweight state while in the visceral depot, it is only observed in severe obesity. This may explain why the latter depot is particularly pernicious in the overweight/obese state as it allows for more rapid lipid fluxes between visceral fat and the liver. Adipose lipid turnover decreases during ageing due to impaired breakdown (lipolysis) of stored triglycerides. If this decline is not compensated by reduced adipocyte lipid uptake, bodyweight will increase over time. In concordance with this, low lipolysis rates are a risk factor for future weight gain and glucose intolerance. Adipose lipid turnover is also decreased in insulin resistance and certain forms of dyslipidemia. Altogether, adult human adipose tissue is in a highly dynamic state. Alterations in the turnover of fat cells and their lipids are therefore novel factors to consider in the pathophysiology of common metabolic disorders.
Pulmonary carcinoma associated with cystic airspaces in two dogs
Authors: Bello A. M. , Anselmi C. , Frau M. , Berman K. G. , Novellas R. , Espada Y. , Longley M. J. , Dhumeaux M. P.
Published: December 2021

Malignant pulmonary neoplasia associated with cystic airspaces is a well‐recognised disease entity in humans. Two elderly dogs, previously diagnosed with a solitary emphysematous bulla, presented with non‐specific clinical signs. At presentation, pulmonary auscultation was unremarkable. In both cases, thoracic CT demonstrated the transformation of the cystic airspace lesions characterised by a progressive increase of the solid component and reduction of the air component. Cytological evaluation and subsequent surgical excision followed by histopathology confirmed pulmonary carcinoma in both cases. These two cases represent the first demonstration of possible malignant transformation of pulmonary cystic airspace in dogs. Veterinarians should consider neoplastic transformation as a differential diagnosis in cases of cystic airspaces, particularly cases with features including thickening or irregularity of the wall, associated soft‐tissue nodules or solid and non‐solid tissue intermixed within clusters of multiple cystic airspaces. Ongoing monitoring of cystic airspace lesions through diagnostic imaging is recommended.
Does the adenosine deaminase (ADA) gene confer risk of sleepwalking?
Authors: Fournier Simon , Dauvilliers Yves , Warby Simon C. , Labrecque Marjorie , Zadra Antonio , Boucetta Soufiane , El Gewely Maryam , Kaddioui Houda , Lopez Régis , Montplaisir Jacques Y. , Bareke Eric , Tétreault Martine , Desautels Alex
Published: December 2021

Sleepwalking is a common non‐rapid eye movement (NREM) parasomnia and a significant cause of sleep‐related injuries. While evidence suggest that the occurrence of this condition is partly determined by genetic factors, its pattern of inheritance remains unclear, and few molecular studies have been conducted. One promising candidate is the adenosine deaminase (ADA) gene. Adenosine and the ADA enzyme play an important role in the homeostatic regulation of NREM sleep. In a single sleepwalking family, genome‐wide analysis identified a locus on chromosome 20, where ADA lies. In this study, we examined if variants in the ADA gene were associated with sleepwalking. In total, 251 sleepwalking patients were clinically assessed, and DNA samples were compared to those from 94 unaffected controls. Next‐generation sequencing of the whole ADA gene was performed. Bio‐informatic analysis enabled the identification of variants and assessed variants enrichment in our cohort compared to controls. We detected 25 different coding and non‐coding variants, of which 22 were found among sleepwalkers. None were enriched in the sleepwalking population. However, many missense variants were predicted as likely pathogenic by at least two in silico prediction algorithms. This study involves the largest sleepwalking cohort in which the role of a susceptibility gene was investigated. Our results did not reveal an association between ADA gene and sleepwalking, thus ruling out the possibility of ADA as a major genetic factor for this condition. Future work is needed to identify susceptibility genes.
Towards resolving taxonomic uncertainties in wolf, dog and jackal lineages of Africa, Eurasia and Australasia
Authors: Krofel M. , Hatlauf J. , Bogdanowicz W. , Campbell L. A. D. , Godinho R. , Jhala Y. V. , Kitchener A. C. , Koepfli K.‐P. , Moehlman P. , Senn H. , Sillero‐Zubiri C. , Viranta S. , Werhahn G. , Alvares F.
Published: December 2021

Successful conservation depends on accurate taxonomy. Currently, the taxonomy of canids in Africa, Eurasia and Australasia is unstable as recent molecular and morphological studies have questioned earlier phenetic classifications. We review available information on several taxa of Old World and Australasian Canis with phylogenetic uncertainties (namely, African jackals, Asian wolves and Australasian dogs), in order to assess the validity of suggested scientific names and provide a scientific basis for reaching a taxonomic consensus primarily based on molecular data, but also including morphology, biogeography and behavioural ecology. We identify major knowledge gaps, provide recommendations for future research and discuss conservation implications of an updated taxonomic framework. Recent molecular studies indicate that the former Afro‐Eurasian ‘golden jackal’ represents two distinct lineages, the golden jackal (Canis aureus) from Eurasia and the African wolf (C. lupaster) from Africa. Phylogenetic research also indicates that the side‐striped and black‐backed jackals form a monophyletic group that branched earlier than Canis, Cuon and Lycaon, which should be reassigned to the genus Lupulella as L. adusta and L. mesomelas, respectively. The Himalayan/Tibetan and Indian wolf lineages appear to have diverged earlier and are distinct from all other grey wolves (C. lupus) based on mitochondrial and nuclear genome data. However, until genome‐wide data from multiple individuals across the range clarify relationships with other taxa, we suggest referring to the Himalayan/Tibetan wolf lineage as Canis lupus chanco. We support the currently accepted nomenclature for the Indian wolf Canis lupus pallipes for the wolf populations found on the Indian subcontinent and possibly also in south‐western Asia (exact geographical boundary pending). The information presented here provides a current and consistent taxonomic framework for use by conservationists and other practitioners, but it is also intended to stimulate further research to resolve current uncertainties affecting the taxonomy of Old World canids.
Membership in a kind: Nature, norms, and profound disability
Authors: Vorhaus John
Published: December 2021

Can rationality serve as the basis of respect for people who do not have this capacity? This paper starts from the assumption that rationality is both the norm for the human species and the basis of respect. The paper considers whether the species norm determines the nature of those profoundly disabled people who do not themselves possess the norm‐related characteristics, and if it does, whether this implies that these same individuals are owed respect. The principal conclusion is that, while a positive response to these questions has its merits, it faces hard questions of its own, some of which appear insoluble. If that is what they are, then any attempt to ground respect for profoundly disabled people on an appeal to rationality as the species norm will fail, and those of us who believe that this group of human beings is owed respect will have to come up with an alternative explanation.
“How dare you?!”: A self‐verification perspective on how performance influences the effects of abusive supervision on job embeddedness and subsequent turnover
Authors: Smith Troy A. , Boulamatsi Artemis , Dimotakis Nikolaos , Tepper Bennett J. , Runnalls Blake A. , Reina Christopher S. , Lucianetti Lorenzo
Published: December 2021

Higher‐performing employees are extremely important to organizations due to their superior contribution to unit performance and vaulted value within their teams. In turn, they espouse higher work‐specific self‐worth (WSSW) evaluations that influence how they react to abusive supervision. Taking a self‐verification perspective, we theoretically explain how performance (through WSSW) augments the aversive nature of abusive supervision, which in turn affects higher‐performing employees’ job embeddedness and subsequent decisions to quit their jobs. Across three field studies, our model is supported as we find that performance is positively related to WSSW, which magnifies the negative effects of abusive supervision on satisfaction. Consequently, we discover that as job performance (and in turn self worth) increases, abusive supervision indirectly reduces job embeddedness and increases turnover through two forms of satisfaction. We expound upon how these findings contribute to both theory and practice.
No increase in alcohol dehydrogenase levels following repeated ethanol exposure in young honeybee workers
Authors: Miler Krzysztof , Stec Daniel , Pardyak Laura , Kamińska Alicja , Kuszewska Karolina
Published: December 2021

Some workers of the honeybee show high alcohol dehydrogenase (ADH) levels and high resistance to the sedative effects of alcohol, yet it is unknown whether these two issues are directly related. Here we looked for a link between ADH levels and sedation latency in response to alcohol exposure. We used molecular and immunoblotting methods to investigate a possible induction of ADH production in young, ADH‐lacking workers in response to repeated ethanol vapour presentation. Although we found increased sedation latency in individuals after several ethanol encounters, this was not accompanied by detectibly increased ADH levels in such workers. The lack of ethanol‐induced ADH production indicated that it was not needed for increased coping with alcohol inebriation. In this work, we expanded current knowledge about the effects of alcohol on honeybee workers and related it to the existing literature on the subject.
The Huge Missing Factor in Leak-Before-Break Analysis: How a Circumferential Through-Wall-Crack in a Pipe System Changes the Flexibility and Reduces the Applied Moments
Authors: Uddin Mohammed , Wilkowski Gery , Kalyanam Suresh , Brust Fedrick
Published: December 2021

In typical leak-before-break (LBB) analyses in the nuclear industry, the uncracked piping normal operating forces and moments are applied in a cracked-pipe analytical procedure to determine normal leakage, and the combined forces and moments under normal operating condition and safe shutdown earthquake seismic loading are used in a fracture analysis to predict margins on “failure.” The International Piping Integrity Research Program (IPIRG) performed in 1990–1998 provided some insights to typical LBB behaviors where pipe system tests were conducted with simulated seismic loadings. The test results showed a large margin on LBB, which was also recognized in 2011 when the Argentinian Atucha II plant was analyzed using a robust full FE model. It was found that when circumferential through-wall cracks were put in the highest stressed locations, the applied moment dropped for both normal operating and N + safe shutdown earthquake (SSE) loading as the crack length increased. The through-wall crack size for causing a double-ended guillotine break (DEGB) was greater than 90% of the circumference. Similar results were also found for a petrochemical pipe system where thermal expansion stresses are much higher than the primary stresses. Even with very low toughness materials, the critical crack size leading to DEGB was greater than 80% of the circumference. The implication of this work is that pragmatically there is much higher margin for DEGB failure in nuclear plant operation, and efforts would be better focused on the potential for a small-break loss-of-coolant accident (SB-LOCA).
Summation of Multi-Finger Vibrotactile Stimuli
Authors: Murray Anne M. , Klatzky Roberta L. , Khosla Pradeep K.
Published: December 2021

We have developed a vibrotactile glove that stimulates the fingertips of the wearer’s hand to convey grip force information while he/she is manipulating remote objects with a robotic hand. In this paper, we present a psychophysical experiment to examine how multi-finger vibrotactile stimulation is perceived by the user. Magnitude estimations of the overall strength of vibration were obtained using sinusoidal signals varying in amplitude and frequency. We have found that increasing the number of fingers stimulated increases the perceived vibration magnitude, but by a rule of diminishing returns. Additionally, we have found that finger separation and thumb “differentiation” are not factors in the magnitude judgements. By using multiple stimulation points, it may be possible to expand the perceived sensitivity range that is used to encode grip force information in a telemanipulation environment; thus a larger range or more refined range of force values can possibly be conveyed to the user.
A New Method for Design and Control of Haptic Interfaces for Display of Rigid Surfaces
Authors: Springer Scott L. , Ferrier Nicola J.
Published: December 2021

This paper addresses the often-cited problems associated with haptic display of rigid bodies or “virtual walls”. Traditional haptic interfaces employ an actuator directly coupled to the human operator that provides a force proportional to wall penetration distance and velocity. A new paradigm for design and control of haptic displays is proposed that utilizes a de-coupled actuator and pre-contact distance sensing to improve stability and response performance. Dynamic models of real human/rigid body contact and prior haptic display models are developed and compared with the proposed method. Errors in the force and energy transfer are identified and associated with virtual wall penetration distance, required in traditional virtual wall haptic models. Results of the simulation of the dynamic models are presented, identifying system force response errors attributable to delay, wall penetration, wall model spring constant, and wall model damping constants.
Hybrid Neural Network for Modeling Automotive Clutches
Authors: Parvataneni V. , Cao M. , Wang K. W. , Fujii Y. , Tobler W.
Published: December 2021

In this paper, artificial neural network (ANN) based models to capture the dynamic engagement torque of a wet clutch system are developed and analyzed. A two-layer recurrent ANN with output feedback is chosen as the baseline architecture since its simplicity allows easy implementation and efficient execution. Although this model exhibits good performance in capturing the overall mean level of the engagement torque as a function of time, it is unable to predict some of the important clutch dynamics behaviors. To improve the performance, additional neurons that represent the first principles of the clutch engagement process are incorporated into the neural network model. In other words, a hybrid model in which physical knowledge is implicitly embedded within the ANN architecture is derived. This hybrid model is trained and tested with experimental data. The results show that the performance of the hybrid network is much superior to that of the baseline ANN. It can successfully capture not only the trends, but also the detailed characteristics of the clutch engagement torque as a function of time.
The “Rutgers Ankle” Orthopedic Rehabilitation Interface
Authors: Girone Michael J. , Burdea Grigore C. , Bouzit Mourad
Published: December 2021

This paper presents a novel ankle rehabilitation device currently under development. The haptic interface component has a Stewart platform structure with pneumatic actuators controlled by an electronic interface. It allows movement of the ankle though its full range of motion. The system communicates with a PC through an RS232 port. The PC will run game-like virtual reality exercises that control the movement and output forces of the device. These simulations will make exercising more enjoyable, transparently recording patient progress for evaluation by therapists.

The “Rutgers Ankle” Orthopedic Rehabilitation Interface will facilitate the healing of one of the most often injured joints of the body. Inherently safe and easy-to-operate, it will combine the capabilities of many current rehabilitation devices. This system will enhance rehabilitation routines by providing three types of exercises: strengthening, stretching, and balancing. Eventually, this system will allow patients to exercise in their homes while being monitored remotely by therapists or physicians.
A Nonlinear Observer for Minimizing Quantization Effects in Virtual Walls
Authors: Madill Daniel R. , Wang David W. L. , Ching Mennas C.
Published: December 2021

Quantization effects can reduce the achievable stiffness of virtual walls. Phase delays introduced by filtering are also an issue. This paper presents a non-linear model-based observer that produces smooth position and velocity estimates with very little delay based on measured position and force signals. Compensation for Coulomb friction and motor saturation is incorporated into the estimator. Use of the estimator in the implementation of a virtual wall yielded higher wall stiffnesses and better performance. Model-based estimator design was possible due to the design of the manipulator. The three degree-of-freedom manipulator employed is direct-drive, gravity-balanced, and dynamically-decoupled with nearly linear dynamics. The robot structure itself is employed as a force sensor, reducing the cost of the device.
A “Kane’s Dynamics” Model for the Active Rack Isolation System
Authors: Hampton R. David , Beech Geoffrey
Published: December 2021

Many microgravity space-science experiments require vibratory acceleration levels unachievable without active isolation. The Boeing Corporation’s Active Rack Isolation System (ARIS) employs a novel combination of magnetic actuation and mechanical linkages, to address these isolation requirements on the International Space Station (ISS). ARIS provides isolation at the rack (International Standard Payload Rack, or ISPR) level.

Effective model-based vibration isolation requires (1) an appropriate isolation device, (2) an adequate dynamic (i.e., mathematical) model of that isolator, and (3) a suitable, corresponding controller. ARIS provides the ISS response to the first requirement. This paper presents one response to the second, in a state-space framework intended to facilitate an optimal-controls approach to the third. The authors use “Kane’s Dynamics” to develop an state-space, analytical (algebraic) set of linearized equations of motion for ARIS.
Real-Time Modeling, Simulation, and Control System Design of a Dual Hybrid Electric Vehicle
Authors: Gospodareva Veronika , Hamel William , Hatmaker Claudell , Hodgson Jeffrey , Jesse Stephen , McCracken John , Rutherford Craig , Smith Matt
Published: December 2021

The Graduate Automotive Technology Education (GATE) Center at the University of Tennessee, Knoxville (UTK) offers courses addressing the simulation, modeling, and control system design of hybrid electric vehicles (HEV). In the Spring of 1999 such a course was conducted to support the UTK FutureCar Challenge entry for 1999. The vehicle modeled is a Dual-configuration Hybrid Electric Vehicle (DHEV) which uses a planetary power-split device similar to the Toyota Hybrid System used in the Toyota “Prius”. The goals of the course included the development of a real-time simulator that could incorporate actual vehicle control hardware in the simulator loop. This “control-hardware-in-the-loop” (CHIL) configuration was used for simulation, control system design, and troubleshooting. This approach allows the simulation of normal vehicle operating conditions as well as emergency fault handling situations in which it may not be desirable to subject the actual prototype vehicle to a given test condition. Additionally, it is possible to do a great deal of control system testing and development without an operating vehicle.
Optical Sensor for Precision Small-Angle Measurement
Authors: Huang Peisen S. , Zhang Aiyu
Published: December 2021

A novel optical sensor for precision small-angle measurement is proposed. It is based on the total internal reflection effect of a light beam at a glass prism. Angular displacement of the light beam is measured by detecting the intensity change of the reflected beam as a result of the relative phase shift between the s- and p-polarized beams. A differential method is developed in which the light beam is equally split into two, each reflected at a prism and detected by a photodiode. The output is the difference of the two detected intensities divided by their sum. It was found that this differential method significantly improves the linearity of sensor output. Both theoretical and experimental results are presented.
A Shear-Force Sensitive Silicon Sensor
Authors: Wang Lin , Beebe David J.
Published: December 2021

A shear-force sensitive silicon sensor is developed using microfabrication technology. Four ion implanted piezoresistive resistors are embedded in a silicon diaphragm and used as independent strain gauges. An epoxy mesa is added on top of the diaphragm to transmit force from the load to the diaphgram. Both the shear and normal components of an applied force can be resolved by measuring the resistance variations of the four resistors. The sensor is tested when a 0-3 N variant force is applied at elevation angles of 0° (normal), 30°, 45° and 60°. At each elevation angle, the sensor rotates from 0° to 360° at an increment of 30°. Good linearity (R > 0.98) and high repeatability (standard deviation < 8 %) are observed. Both normal and shear sensitivities are measured. The shear sensitivity is characterized in terms of both magnitude and direction of the applied force. The results show that the sensor has a high sensing ability to both normal and shear forces (compared to commercial load cell). In this paper, the sensor design, fabrication and testing are described. The sensor characterization and shear sensing ability are discussed.
The Degree of Translational-Rotational Coupling of a Spatial Stiffness
Authors: Huang Shuguang , Schimmels Joseph M.
Published: December 2021

Previously, we have shown that, to realize an arbitrary spatial stiffness matrix, spring components that couple the translational and rotational behavior along/about an axis are required. We showed that, 3 such coupled components and 3 uncoupled components are sufficient to realize any full-rank spatial stiffness matrix and that for some spatial stiffness matrices 3 coupled components are necessary. In this paper, we show how to identify the minimum number of components that provide translational-rotational coupling required to realize an arbitrarily specified spatial stiffness matrix. This number is defined as the “degree of translational-rotational coupling” (DTRC). We show that the DTRC of a stiffness matrix is uniquely determined by the spatial stiffness mapping and is obtained by evaluating the eigenstiffnesses of the spatial stiffness matrix. In addition, the relationships between the DTRC and other properties identified in previous investigations of spatial stiffness behavior are discussed.
Design of the NASA Robonaut Hand
Authors: Lovchik C. S. , Aldridge H. A. , Diftler M. A.
Published: December 2021

The design of a highly anthropomorphic human scale robot hand for space based operations is described. This five finger hand combined with its integrated wrist and forearm has fourteen independent degrees of freedom. The device approximates very well the kinematics and required strength of a space suited astronaut’s gloved hand. The mechanisms used to meet these requirements are explained in detail along with the design philosophy behind them. Integration experiences reveal the challenges associated with obtaining the required capabilities within the desired size. The initial finger control strategy is presented along with examples of obtainable grasps.
The Manta and the Kanuk: Novel 4-DOF Parallel Mechanisms for Industrial Handling
Authors: Rolland Luc H.
Published: December 2021

Two novel 4-DOF very fast parallel robots were designed. This paper introduces the new parallel mechanism designs which are named the Manta and the Kanuk. In order to reduce manipulator overall costs, the actuator and encoder numbers are minimized to the exact effective degrees-of-freedoms (DOF) which is usually not the case in most parallel robot designs. The robots allow end-effector displacements along the three Cartesian translations and one platform transversal rotation. The two remaining rotations are blocked by the intrinsic mechanical structure including the rotation along the platform normal which is always limited in range. The main advantages are high stiffness through the multiple kinematic chain structure which allow for low mass designs. Moreover, they feature simple mechanical construction. Thus, it shall be possible to achieve very high throughput since high accelerations are feasible. To circumvent the known workspace limitations, the actuators were selected to be prismatic along linear axes. The applications are automated warehouse manipulation, mediatheque manipulation, machine tool tool changers, loading and unloading.
Sensorless Velocity Estimation for Control of a Compliant Mechanism Based Micromanipulator
Authors: Fite Kevin , Goldfarb Michael
Published: December 2021

A classical state observer-based approach to velocity estimation for the position control of a robot manipulator is compared with a self-sensing approach. The former is essentially an analog differentiator, while the latter utilizes a model of the actuator to reconstruct the velocity signal. The two methods of velocity estimation are compared in two common robot control schemes implemented on a compliant-mechanism-based small-scale robot manipulator. Specifically, both the state-observer-based and the self-sensing velocity estimates are utilized in the PD-control and in the sliding-mode control of the manipulator motion. Experimental results indicate that the self-sensing approach offers better control performance than does the state-observer-based approach, especially in the sliding-mode controller. The results are particularly useful in the motion control of micromanipulators, since the small scale constrains the size and number of sensors on the manipulator.
Emulation of Biological Motor Primitives in an Artificial System: The Generation of Static Force Fields
Authors: Lee Chae J. , Reger Bernard D. , Tresch Matthew C. , Colgate J. Edward , Mussa-Ivaldi Ferdinando A.
Published: December 2021

We have used observations of posture and movements in biological limbs to derive a controller for an artificial mechanism. The controller architecture emulates some of the known relations between spinal cord circuitry and the musculoskeletal system of vertebrates and, specifically, of the rat. This work relates to recent experiments suggesting that the neural circuitry of the spinal cord may be partitioned into a small set of functional modules. Activation of these modules, each connected to a set of limb muscles, resulted in force fields that have been measured at the endpoint of a limb. These force fields map each position of the foot into a corresponding static force vector. The force fields have been found to converge toward equilibrium positions located inside the leg’s workspace. The experimental observation that vector fields induced by multiple stimulations add vectorially, suggested that convergent force fields form a system of building blocks (or “primitives”) for the generation of stable postures and movements. To emulate this biological mechanism in the control of an artificial two-joint limb, we established relationships among three hierarchical levels — spinal modules, muscles, and actuators — by deriving the mappings among the respective output fields. These mappings are used in combination with an inverse model of the actuators to calculate the actuator commands that generate a desired force field. We tested the ability of this control system to reproduce the force fields generated by the leg muscles of the rat and a set of force fields with significant geometrical features. Our results show that we can successfully and reliably transfer to our artificial system the features of muscle force fields. In addition, we exploited the same principle of vector summation observed in the biological system to combine these muscle fields into a variety of force field patterns, including the gradients of Gaussian potentials and locally parallel fields. We consider this a first step in the generation of a biomorphic motor control system. This work is supported by ONR grant N00014-95-1-0571 and NIH grant MH48185.
Design and Development of a Variable Geometry Prototype Manipulator
Authors: Chu M. , Modi V. J. , de Silva C. W. , Misra A. K.
Published: December 2021

The paper focuses on design, dynamical simulation, operation and performance evaluation of a variable geometry manipulator. The system is composed of a mobile base supporting two modules connected in a chain topology. Each module consists of two links: one free to slew while the other is permitted to deploy. The governing equations of motion for the planar dynamics of the manipulator system are obtained using the Lagrangian procedure. Results indicate that the coupling effects together with the flexibility at the revolute joints have significant impact on the manipulator’s performance. Obviously, this will affect the desired trajectory tracking by the end-effector, suggesting a need for a suitable control algorithm. This is achieved through the classical Proportional-Integral-Derivative (PID) control strategy. The numerically predicted results are compared with the prototype performance. The remarkable agreement tends to substantiate integrity of the prototype design and effective implementation of the controller.
On Crack Extension in TSD Specimen With Foam Core
Authors: Li Xiaoming , Carlsson Leif A.
Published: December 2021

The Tilted Sandwich Debond (TSD) specimen has recently been introduced for characterization of debond fracture of sandwich structure. A precracked sandwich is attached to an incline, and debonding is achieved by loading the partially debonded top face until further crack propagation occurs. In this paper we present numerical finite element analysis of stress intensity factors for several configurations of the TSD specimen, viz. crack in a homogeneous specimen, crack located at the face/core interface, and crack located slightly below the face/core interface. The tendency for crack kinking is examined over a range of tilt angles. The stress intensity factors and mode mixty displayed very little dependency on the tilt angle, but the results were shown to depend on the exact crack configuration.
Stability of Long Cylindrical Sandwich Shells With Dissimilar Facings Subjected to a Lateral Pressure
Authors: Birman Victor , Simitses George
Published: December 2021

The paper presents the analysis of buckling and initial postbuckling behavior of long cylindrical sandwich shells subjected to a lateral pressure. The shells considered in the paper have dissimilar facings reflecting a demand to enhance impact resistance and damage tolerance of the facing exposed to external loads and hostile environments that are typical in applications. The shell being long, its central section remains in the state of plane strain prior to and after buckling. The solution includes the analysis of prebuckling deformations and linear and nonlinear buckling problems. It is shown that prebuckling deformations affect postbuckling shell behavior but they do not affect the linear (upper) buckling pressure. Numerical results presented in the paper illustrate that a moderate redistribution of the layers between the facings results in a limited reduction of the buckling pressure compared to the case of symmetric facings.
Particulate Enhanced Damping in Sandwich Structures
Authors: Maley Scott , Sun C. T.
Published: December 2021

This paper investigates the damping effect of loose particulate within the core of sandwich structures. Beam specimens fabricated from aluminum honeycomb core and IM7 carbon fiber face sheets with various amounts of loose particulate are experimentally examined. Both free vibration and forced vibration tests are performed. It is shown that a moderate amount of particulate can cause a large increase in damping. The effect of varying amounts of particulate is also investigated. Plate equations of motion with damping and inertia terms are derived to model the beam and compare with experimental results. Effective mass and effective viscous damping are generated by matching the theoretical model to the experimental data.
New Formulation for Composite Sandwich Shell Finite Element
Authors: Tabiei Ala , Tanov Romil
Published: December 2021

Sandwich shell finite element formulation is developed and presented. The sandwich shell element formulation allows for orthotropic faces and core material. The sandwich shell element is based on first shell order shear deformable theory utilized by most shell finite elements for isotropic materials. Consequently, the presented procedure can be adopted for any shell element available in commercial finite element packages. The formulation is based on the equalities of stress and moment resultants between a sandwich shell element and a typical homogenous shell element. The developed element is implemented in the nonlinear finite element code DYNA3D to validate and check its accuracy, efficiency and overall performance. The predicted results show good agreement with results obtained from far more complicated and computationally intensive 3-D analyses.
Past, Present and Future Composite Structures Applications in Rotorcraft
Authors: Rousseau Carl , Dobyns Al , Minguet Pierre
Published: December 2021

The rotorcraft industry is a roughly $5B/year segment of aerospace, with a 4:1 military to civil sales ratio, that delivers on the order of 5000–6000 aircraft per year. The earliest rotorcraft had composite primary structure: bonded wooden main and tail rotor blades. The first advanced composite main rotor (M/R) and tail rotor blades (bonded glass/epoxy D-spars, honeycomb afterbodies, and fabric skins) went into production in the early ’70’s. Thus, the rotorcraft industry has been designing and certifying nonredundant bonded primary composite structure for over 25 years. More recent design innovations for rotor components include 4-inch-thick solid molded bearingless M/R hubs and yokes (joining the blades to the mast) and a 1.5-inch-thick complex curvature fiber placed carbon grip for the Bell/Boeing MV-22 Osprey tiltrotor. With roughly 50% of its empty weight consisting of glass and carbon reinforced composites, the V-22 probably has the highest weight-percentage of composites of any manned military production aircraft. This degree of composites usage will likely be surpased by the Sikorsky/Boeing RAH-66 Comanche scout/attack helicopter when it goes into production. As with the V-22 and RAH-66, composites are also seeing increased usage in civilian rotorcraft airframes. Specifically, the Bell 427 and MD Helicopter MD900 Explorer light twin helicopters feature all-composite fuselages, while the Bell-Agusta BA609 civil tiltrotor will have carbon epoxy wings, fuselage and empennage much like the V-22. In the future, composite structural applications will become more widespread as designers gain insight and confidence. Repair, maintenance and support of these structures will become the focus of much engineering R&D effort.
Breaking the 1:1 Immersion Barrier
Authors: Pimentel Kenneth , Ferneau Mark , Anderson Gavin
Published: December 2021

This paper discusses a combination of techniques that lets stylists and designers experience believable 1:1 interactions with virtual prototypes using immersive environments. The intent is to replace physical prototypes with believable virtual prototypes and then use them as the basis for communicating design intent within formal or informal design reviews. Achieving a reasonable degree of “believability” and natural interaction within this context requires addressing a broad range of problems, including: perception of scale, varying frame-rates, non-intuitive interaction devices and process and data integration just to name a few.

In addition to these challenges, designers and stylists want to examine multiple forms of product data including bitmaps, movies, text information and 3D data within a single visual context. This paper describes an approach for visualizing and interacting with various forms of product data within a fully immersed environment for the purposes of concept design (the phase of product design where the overall functionality and shape of the product is determined [Kraftcheck, 1997]).
A Framework for Augmented Reality Based Collaborative Product Development
Authors: Agarwal S. , Huang C. P. , Liou F. W. , Mitchell O. R.
Published: December 2021

The aim of this paper is develop a framework for a system for collaborative product development using Internet and augmented reality technology. The system allows fruitful interaction between experts at geographically dispersed locations through a flexible environment for sharing of information which could be in the form of live video, computer-aided design, audio, textual or conceptual. This system will provide a new paradigm for flexible interaction between the vendors and/or the domain experts at different stages of the product development cycle in order to reduce turn-around time. Also the system can be used in the classroom as a demonstration tool or in distance learning environment to introduce the concept of distributed collaborative engineering to students.
Comparative Testing of Virtual Environment Display Devices for Conceptual Design Reviews
Authors: Bochenek Grace M. , Ragusa James M.
Published: December 2021

The high cost of designing and prototyping new products and systems, coupled with the need to shrink overall life cycles, requires that organizations become more effective and efficient in managing these processes. To this end, empirical testing of various virtual environment (VE) devices was conducted to evaluate their use during a conceptual design review of a new military vehicle. Test results and analysis indicated that there were significant advantages of some VE technologies during certain phases of the review process, but no single device fully satisfied all individual and team needs. For that reason, a combined technology approach is recommended.
A Computational Acoustic Field Reconstruction Process Based on an Indirect Variational Boundary Element Formulation
Authors: Zhang Zhidong , Vlahopoulos Nickolas , Raveendra S. T. , Allen T. , Zhang K. Y.
Published: December 2021

The objective of the work presented in this paper is to develop a computational capability based on the indirect variational boundary element method (IVBEM) to evaluate appropriate velocity boundary conditions on an assembly of piston type sources such that they can recreate a prescribed acoustic field. Information for the acoustic pressure of the original acoustic field at certain field points constitutes the input to the developed process. Several new developments associated with the IVBEM are completed within the field reconstruction process. A new formulation for treating irregular frequencies in the IVBEM is developed and implemented in the field reconstruction process. The velocities on the piston type sources are computed from transfer functions between the field points, where the acoustic pressure of the original field is prescribed, and the velocity boundary condition on each element of the generic source. The IVBEM is employed for computing the transfer functions. A singular value decomposition solver is integrated with the IVBEM computations in order to evaluate the velocity boundary conditions from the transfer functions. Finally, an algorithm is developed that identifies the optimum field points where the acoustic pressure of the original field must be prescribed. The optimum field points are selected from a set of prescribed candidate points. The selection of the optimum points is based on the geometric characteristics of the generic source, the frequency of analysis, and the properties of the medium. Several validation and application cases are presented.
Flow Measurements and Analysis for Automotive Blower Noise
Authors: Humbad Niranjan G. , Foss John F. , Prevost Richard J. , Chen Charles C.
Published: December 2021

The climate control air handling system is one of the major contributors to automobile interior noise. The most annoying features can be characterized as low frequency (<= 400 Hz) “rumble”, and “blade passing frequency, BPF tone” noise. This study presents an experimental investigation for two blower scroll assemblies, namely ‘baseline’ and ‘modified’. The baseline assembly is the original scroll which exhibited both tone and rumble noise problems. This assembly was modified to significantly reduce the tone and rumble noise. The velocity power spectral density plots of flow velocity show areas within the blower scroll where the turbulence fluctuations are relatively high for the tone and rumble frequencies, and are lower in magnitude for the modified case. A detailed CFD analysis was performed to compare the mean flow velocity components for the two assemblies. The results are in good agreement with the measurements. CFD analyses, which have been confirmed by experimental data, can be used to predict beneficial geometric alterations to minimize the tonal and rumble noise sources in climate control flow systems.