bluuebunny/crossref_metadata_2025 huggingface dataset:
Patient participation in healthcare activities: Nurses' and patients' perspectives in Taiwan
Authors: Kao Hsueh‐Fen S. , Hung Chang‐Chiao , Lee Bih‐O , Tsai Shu‐Ling , Moreno Oscar
Published: December 2021

Patient participation in healthcare activities is key to producing successful patient‐centered care. However, little is known about both nurses' and patients' perspectives regarding patient participation in East Asia. This paper compared and contrasted perspectives of patient participation in healthcare activities between nurses and patients, using a qualitative study with a purposive sample of 39 nurses and 15 patients. A semi‐structured interview was applied to focus groups for nurses, and to face‐to‐face interviews for patients. Content analysis was utilized to analyze the data, and common themes and subthemes were identified showing three similarities (authoritative culture, participation behaviors, and obstacles to participation), and two differences (sources of acquiring patient‐related health information, and responsible party). Nurses and patients did not entirely view participation in healthcare activities congruently. Relevant clinical practices are also suggested, including respecting patients' autonomy, nurses' using layman’s language for explanations, patients' understanding the meaning behind their participation behaviors, recognizing obstacles faced in enhancing patient participation with adjusted nursing workload, actively providing needed health information, and leading patients to realize that they will be responsible for their health behaviors after discharge.
Exploring resilience and workplace adversity in registered nurses: A qualitative analysis
Authors: Tabakakis Costantinos (Kosta) , McAllister Margaret , Bradshaw Julie
Published: December 2021

The aim of this study was to explore New Zealand registered nurses' experiences of resilience and workplace adversity. Resilience research in nursing has concentrated on quantitative and individual aspects. Contextual factors have been largely ignored. This study addresses this gap by qualitatively researching and documenting nurses' experiences of resilience and workplace adversity. An online survey of New Zealand registered nurses was conducted in 2018. Qualitative responses were analyzed using Braun and Clarke's thematic analysis method. Three themes emerged: (i) perseverance; (ii) how the past influences my present resilience; and (iii) things I do to stay strong. Nurses rely on personal resilience to overcome workplace adversity. Health service organizations must implement policies and procedures that (i) reduce workplace adversity, and (ii) encourage and develop strategies for nurses to individually and collectively face adversity with resilience. Future research needs to explore how healthcare organizations can modify existing systems and structures to align with nurses' efforts to sustain and develop resilience.
Two phylogenetically unrelated peptide‐receptor modules jointly regulate lateral root initiation via a partially shared signaling pathway inArabidopsis thaliana
Authors: Jourquin Joris , Fernandez Ana Ibis , Parizot Boris , Xu Ke , Grunewald Wim , Mamiya Akihito , Fukaki Hidehiro , Beeckman Tom
Published: December 2021

Peptide‐receptor signaling is an important system for intercellular communication, regulating many developmental processes. A single process can be controlled by several distinct signaling peptides. However, since peptide‐receptor modules are usually studied separately, their mechanistic interactions remain largely unexplored.

Two phylogenetically unrelated peptide‐receptor modules, GLV6/GLV10‐RGI and TOLS2/PIP2‐RLK7, independently described as inhibitors of lateral root initiation, show striking similarities between their expression patterns and gain‐ and loss‐of‐function phenotypes, suggesting a common function during lateral root spacing and initiation.

The GLV6/GLV10‐RGI and TOLS2/PIP2‐RLK7 modules trigger similar transcriptional changes, likely in part via WRKY transcription factors. Their overlapping set of response genes includesPUCHIandPLT5, both required for the effect of GLV6/10, as well as TOLS2, on lateral root initiation. Furthermore, both modules require the activity of MPK6 and can independently trigger MPK3/MPK6 phosphorylation.

The GLV6/10 and TOLS2/PIP2 signaling pathways seem to converge in the activation of MPK3/MPK6, leading to the induction of a similar transcriptional response in the same target cells, thereby regulating lateral root initiation through a (partially) common mechanism. Convergence of signaling pathways downstream of phylogenetically unrelated peptide‐receptor modules adds an additional, and hitherto unrecognized, level of complexity to intercellular communication networks in plants.
Choroidal vascularity index changes during the Valsalva manoeuvre in healthy volunteers
Authors: Sevik Mehmet Orkun , Çam Furkan , Aykut Aslan , Dericioğlu Volkan , Şahin Özlem
Published: December 2021

Purpose

To evaluate the effects of the Valsalva manoeuvre (VM) on the choroidal vascularity index (CVI) in healthy volunteers.

Methods

This prospective, cross‐sectional study included 60 eyes of 30 healthy volunteers. Enhanced depth imaging‐optical coherence tomography scans of both eyes involving the fovea were taken, and a 1500 μm subfoveal choroidal area was selected for image binarization with open‐access Fiji software. The binarized image was segmented into the stromal area (SA) and luminal area (LA), and CVI was calculated as the ratio (%) of LA to the total choroidal area (TCA). CVI, subfoveal choroidal thickness (SFCT), IOP, systolic and diastolic blood pressure were evaluated at rest and during the VM.

Results

During the VM, a mean ± standard deviation increase in LA (0.02 ± 0.05 mm2, p < 0.001) and CVI (1.72 ± 2.83%, p < 0.001) was observed, whereas SA (−0.02 ± 0.05 mm2, p < 0.001) decreased. There was no significant change in TCA (0.00 ± 0.03 mm2, p = 0.55) or SFCT (1.05 ± 10.92 μm, p = 0.46). There was a moderate positive correlation between the spherical equivalent refractive error (SE) and SFCT both at rest and during VM (r58 = 0.49, p < 0.0005 and r58 = 0.49, p < 0.0005, respectively). However, there was no significant correlation between SE and CVI either at rest or during VM (p = 0.11 and 0.06, respectively). In a multiple linear regression analysis, CVI was only associated with SFCT; however, SFCT was also associated with SE, both at rest and during VM (p < 0.001).

Conclusion

Valsalva manoeuvre increases CVI by choroidal vascular dilation as demonstrated by an increase in LA and a decrease in SA. Researchers should be careful about unintentional VM during examinations.
Putting the international in Public Administration: An International Quarterly. A historical review of 1992–2022
Authors: Aoki Naomi , Elliott Ian C. , Simon Jeanne , Stazyk Edmund C.
Published: December 2021

Over the last 30 years significant efforts have been made to ensure that Public Administration: An International Quarterly lives up to its international title. In this review article, we highlight some of the key research articles that have been published by the journal which illustrate an international approach to the study of public administration. We show how the journal's historical inclusion of a diverse spectrum of philosophies, methodologies, theories and contexts has contributed to this internationalization. In doing so the journal has contributed to our understanding of equity, social justice and inclusion; ethics, public value and corruption; networks, governance and participation; and environmental governance and crisis management. This historical review also reveals how global challenges, particularly as a consequence of the climate emergency, drive the transnationalization of public administration, which in turn requires further international scholarship.
Congenital red hair heterochromia in the background of blond scalp hair
Authors: Drew Cassandra , Shin Leah , McGowan Maria , Furukawa Betsy
Published: December 2021

We report a case of isolated patchy red hair heterochromia of the scalp in a healthy 6‐year‐old boy. Isolated patchy scalp hair heterochromia is the presence of two or more colors of hair in the same individual, thought to be due to genetic mosaicism although no specific etiology has been widely accepted. We have outlined a basic approach to diagnosing different types of heterochromia for clinical application.
The effectiveness of a high‐intensity interval games intervention in schoolchildren: A cluster‐randomized trial
Authors: Martínez‐Vizcaíno Vicente , Soriano‐Cano Alba , Garrido‐Miguel Miriam , Cavero‐Redondo Iván , Medio Enrique Prada de , Madrid Vanesa Martínez , Martínez‐Hortelano Jose Alberto , Berlanga‐Macías Carlos , Sánchez‐López Mairena
Published: December 2021

The aim of this study was to assess the effectiveness of a high‐intensity interval training (HIIT) intervention based on playground games (MOVI‐daFit!) on improvements in adiposity, physical fitness, and cardiometabolic risk factors in schoolchildren. A cluster‐randomized controlled trial (RCT) was performed that included 562 schoolchildren (9–11 years) from 10 schools in Cuenca, Spain. The intervention consisted of four 60‐min sessions per week in the school setting. Analyses were conducted on the intention‐to‐treat basis. Changes in physical fitness parameters (cardiorespiratory fitness: main outcome), body composition, blood pressure, and biochemical cardiometabolic risk parameters were analyzed using both mixed linear and logistic regression models, controlling for baseline covariates, Tanner stages, health dietary score index, body mass index, and cluster factor school. In boys, no significant differences in any outcome measure were noted except for the standing long jump test (10.13 cm; 95% CI 2.94 to 17.32; p = 0.006) between the intervention group (IG) and the control group (CG). Improvements in mean arterial pressure (−1.68 mmHg; 95% CI −3.28 to −0.08; p = 0.039), the triglyceride/HDL‐c ratio (−0.36 mg/dl; 95% CI −0.59 to −0.13; p = 0.002), C‐reactive protein (−0.23 mg/L; 95% CI −0.43 to −0.03), VO2max (1.44 ml/kg/min; 95% CI 0.52 to 2.36, p = 0.002), 20‐m shuttle run test (3.64 laps; 95% CI 0.51 to 6.78), and standing long jump test (7.04 cm; 95% CI 1.21 to 12.87; p = 0.018) were observed in girls in the IG compared with those in the CG. Body composition parameters did not change significantly in either boys or girls. Additionally, children with lower fitness levels obtained greater improvements than children with higher fitness levels. In conclusion, MOVI‐daFit! may represent a good strategy for incorporating HIIT into playground games, although its implementation may need to be improved to extend the benefits to children and enhance its adherence.
Sex differences in toddlers’ negative attributions to challenges: Associations with maternal emotion coaching and emotional awareness
Authors: Perkins Haiden A. , Brophy‐Herb Holly E. , Hyunjin‐Choi Hailey , Williams Jessica , Dalimonte‐Merckling Danielle , Mitchell Koi , Vallotton Claire D.
Published: December 2021

Children's attributions during challenge have roots in toddlerhood with the onset of self‐evaluative emotions and may reflect sex differences in early socialization practices. This study examined toddler sex as moderating associations between mothers’ (n = 104, 73.1% White, 75% with a college degree or more) characteristics (low emotional awareness, emotion coaching beliefs) and toddlers’ (Mage = 26.4 mos.; 51 girls) self‐evaluative negative attributions of difficulty during a challenging lab task. Negative attributions reflected self‐directed comments such as “I can't do it.” Girls made more negative self‐attributions in the context of mothers’ lower emotional awareness whereas boys made more negative self‐attributions in the context of mothers’ greater emotion coaching (medium effects). Results demonstrate early sex differences in toddlers’ negative self‐attributions to challenge.
Weed seed mass affects seedling establishment and resource allocation patterns across a cereal rye surface residue gradient
Authors: Ficks Teala S. , Lowry Carolyn J. , Wallace John M.
Published: December 2021

Knowledge of weed population‐ and community‐level responses to the integration of cover crop surface residues (CCSRs) is vital to understanding their value when integrated into no‐till field crop production systems. Ecological theory suggests that weed seedling survival and resource allocation patterns during the establishment phase should be influenced by the interaction between seed mass and CCSR levels. We conducted a greenhouse experiment to investigate seedling establishment rates and resource allocation patterns in response to increasing CCSR levels across a seed mass gradient, including weed and crop species. The experiment utilised a two‐factor treatment structure, including 10 plant species that varied in seed mass by three orders of magnitude and four cereal rye mulch levels (0, 3360, 6720 and 10,080 kg ha−1). Our results support the hypothesis that the effect of CCSRs on seedling establishment rates is a function of seed mass. Analysis by species showed a decrease in seedling establishment rates of dicotyledon species across all CCSR levels, but this relationship varied among monocotyledon species. CCSR levels were positively correlated with resource allocation to the hypocotyl and specific hypocotyl length of dicotyledon species. Increasing CCSR levels decreased allocation of resources to roots in broadleaved species but did not affect resource allocation patterns in monocotyledon species. We conclude that the combined effects of CCSRs on seedling establishment rates and resource allocation could significantly influence weed population‐ and community‐level dynamics.
Review of the Discussion Section of Research Articles: Rhetorical Structure and Move
Authors: Al-Shujairi Yasir Bdaiwi
Published: December 2021

The discussion section forms an integral part in the writing process of a research article (RA). Research authors find it difficult to write and produce a well-structured discussion for their findings. The reason could be due to the unawareness of the main components (rhetorical moves) that shape this section. Therefore, this paper aims to provide a review of the studies that have been done to analyze the discussion section of RAs over the last 36 years. Also, this review seeks to examine the discussion section of RAs across various scientific disciplines and different types of journals. The review showed that the rhetorical structure of RAs discussion section witnessed some changes over the course of time. New moves such as Research Implications and Research Limitations started to be parts of the discussion section of RAs. In addition, it was revealed that differences in writing the discussion section can be varied broadly across disciplines such as soft sciences (e.g., applied linguistics, sociology, psychology) and hard sciences (e.g., engineering, chemistry, biology) and slightly across types of journals such as ISI and local journals. In conclusion, this paper offered several suggestions for further research to be conducted in the area.
Language Learning Strategies (LLS) Implementation of Students and Teachers at a Malaysian Pre-Tertiary Educational Institution
Authors: Kussin Haddi @ Junaidi , Bahari Aireen Aina , Megat Khalid Puteri Zarina , Raja Harun Raja Nor Safinas , Haji Ali Nor Liza , Mohd Zin Zuhana , Mohamad Taib Mohd Farez
Published: December 2021

The study which took place at a Malaysian pre-tertiary educational institution aimed at investigating the implementation of language learning strategies (LLS) of its two major stakeholders, namely the students and the teachers. As the study employed mixed-method design, both quantitative and qualitative data were collected as to report the findings. The Strategy Inventory for Language Learning Strategies (SILL) and classroom observation protocol were the two important instruments for this study. A total of 300 students were involved in the study in which the number was determined using Krejcie and Morgan table. The students were divided into two groups consisting of 150 students who passed the institution’s English Proficiency Test, being referred to as ‘EPT-pass’ and 150 students who failed the test, hence known as ‘EPT-fail’ in the study. Four teachers voluntarily involved in the study after invitation to be part of the study was extended to all teachers at the educational institution. Analysis of data was done using descriptive statistics (mean and standard deviation scores) and thematic analysis. The findings showed that students employed indirect language learning strategies more than direct strategies with EPT-pass group recording (M=4.084, SD=0.625) and EPT-fail group with (M=2.722, SD=0.466). It was apparent that metacognitive strategies (M=4.361, SD=0.954) were EPT-pass group’s most employed strategies while EPT-fail students implemented affective strategies (M=3.077, SD=0.399) the most. Additionally, LLS were undoubtedly embedded into the lesson implementations of the four teachers whose lesson implementations were observed. The study implies that LLS play fundamental part in the teaching and learning of English and should be directly nurtured and embedded into English language classrooms to ensure more effective implementations.
Is it the Thought that Counts? An evaluation of Digital Archaeological Data Archiving in Catalonia
Authors: Batlle Baró Sabina
Published: December 2021

Archaeological data archiving has not been a major concern in Catalonia. The heritage legal corpus does not engage with the archiving and curation of archaeological data other than the excavation reports. However, it highlights the responsibility of the administration in cataloguing and disseminating the cultural heritage. For this reason, a lot of effort has been invested during the past few years in inventorying known archaeological sites and publishing archaeological reports, with the aim of increasing the transparency of the administration towards its citizens. This article describes the present situation for archaeology in Catalonia, its legal framework and the main initiatives carried out to archive, manage, and publish archaeological data from a user's point of view. Its main aim is to evaluate the current state of archaeological data archives and public databases by analysing the existing platforms with a set of indicators. This assessment leads to the conclusion that the current repositories and databases could be more worthwhile if some limitations were overcome, but also that the advance in archaeological data archiving is restricted by existing law.
Temperature Profiles During Cryolipolysis
Authors: McClintock Dillon H. , Wright Neil T.
Published: December 2021

Cryolipolysis (CLL) is a noninvasive clinical procedure for local reduction of adipose tissue. Paddles as cold as −10 °C are pressed against the skin to cool the subcutaneous adipose tissue (SAT) to ∼10 °C, crystalize the stored triglycerides, and trigger apoptosis in the adipocytes. Occasional adverse effects occur following CLL. There is some uncertainty in the temperature profile during the procedure. Here, a Green's function solution of the one-dimensional (1D) Pennes equation is used to examine how uncertainties in thermal diffusivity and blood perfusion may change the temperature profile during CLL. Improved description of the temperature profile might aid in understanding the mechanisms leading to these adverse effects. The plausible range of values of blood perfusion adds significant uncertainty to the temperature profile during treatment.
Perceiving Roughness via a Rigid Probe: Effects of Exploration Speed
Authors: Klatzky R. L. , Lederman S. J. , Hamilton C. , Ramsay G.
Published: December 2021

This study investigates the psychophysical consequences for roughness perception of altering the speed with which textured surfaces are explored using a rigid probe. Two ranges of probe speed are used: a 4-fold change (Experiment 1) and a 10-fold change (Experiment 2). The data are examined in terms of the effects of speed upon the psychophysical roughness functions (i.e., perceived roughness as a function of interelement spacing). In addition, we perform a global comparison of the relative magnitude of haptic speed effects across current and previous experiments, using a new measure that we derive here. We discover that roughness constancy declines as the range of speed is reduced, sometimes quite substantially so. The results are considered as well in terms of their implications for producing and exploring simulated textures with haptic interfaces for teleoperation and virtual-environment systems.

While we most often touch objects directly with our bare hands, we also frequently use intermediary links such as tools to bring about such interactions. In this paper, we report the results of two psychophysical experiments that extend our recent work (Klatzky & Lederman, 1999; Lederman & Klatzky, 1999) on how people perceive surface roughness via rigid probes. The current experiments investigate the effects of probe speed on roughness perception under active exploration. A more comprehensive paper, which also includes comparable results for passive touch (the surfaces are moved across a stationary probe), has been submitted1. In addition to their contribution to psychophysical issues pertaining to the sense of touch, the results are also relevant to the preparation and exploration of synthetic texture information by means of haptic interfaces for teleoperator and virtual-environment systems.
Frame Mapping and Motion Constraint Effects on Task Performance in Robotic Endoscopic Surgery
Authors: Lai Fuji , Howe Robert D. , Millman Paul A. , Sur Sudipto
Published: December 2021

This paper presents the implementation and evaluation of a minimally invasive surgical system whereby a surgeon can maintain as natural a spatio-motor mapping as possible using a 4 DOF constrained slave robot. One way to achieve this interface is to interpose a robotic system between surgeon and patient which will act as a translator between the 6 degree-of-freedom open surgery-like motions of the surgeon and corresponding endoscopic motions within the patient. Our goal was to find the interface that was easiest to learn. We investigated the effects of different master-slave mappings (screen-mapped versus instrument-mapped) and master dexterities (6DOF versus 4 DOF) by means of performance measures noted on simple surgical tasks. This interface has been found to allow motions very similar to those used in natural prehension and open surgery. The particular combination of instrument-based master-slave mapping and 4DOF master has been found to be especially advantageous.
Passivity-Based Nonlinear Control Strategies for Strict Feedback Form Systems
Authors: Alleyne Andrew
Published: December 2021

This paper presents a tracking algorithm for the control of nonlinear dynamic systems represented in Strict Feedback Form. The construction of the stabilizing algorithm is given using Passivity-based arguments which result in a Passivity-Based Controller (PBC). Also shown are simulations demonstrating the performance of the suggested approach. This paper also shows a direct comparison with the most popular control strategy for Strict Feedback Form Systems: Integrator Backstepping. It is shown that although Integrator Backstepping has several advantages, most notably flexibility in designing output feedback and adaptive approaches, there do exist important situations that favor the PBC. When the model structure is poorly known, the PBC contains diagnostic effects allowing it to systematically pinpoint parts of the model containing inaccuracies. Moreover, the PBC can be simpler to implement than the Backstepping algorithms in the non-adaptive, state feedback case.
Inclusion Probing: Signal Detection and Haptic Playback of 2D FEM and Experimental Data
Authors: Yan Joseph , Scott Paul K. , Fearing Ronald S.
Published: December 2021

The task of probing a medium for an inclusion is cast as a signal detection problem. A sufficient statistic is developed for determining the existence and location of an inclusion. The analysis shows the human limitations of palpation when using a probe and the limitations imposed by a haptic display either when emulating such an environment or when relaying related information in a teleoperated system. Force calculations using FEM models were compared to data measured from constructed gels. Psychophysics experiments demonstrated promising results for the playback of the FEM data.
A Tactile Display Using Ultrasonic Elastic Waves in a Metal Tapered Membrane
Authors: Nara Takaaki , Maeda Taro , Yanagida Yasuyuki , Tachi Susumu
Published: December 2021

The purpose of the study is the development of a tactile display which can control a spatial pattern of friction on a metal surface by using ultrasonic elastic waves in a tapered membrane (a membrane whose width decreases gradually). It is reported that, a surface of a vibrating object with ultrasonic frequency feels smooth by air lubrication called squeeze effect. In this paper, we show two properties of elastic waves in the tapered membrane. First, waves can be localized on the surface. Second, the localized vibrating area can be freely controlled (enlarged or reduced) by changing the frequency of the wave. Therefore, by generating ultrasonic elastic waves in the metal tapered membrane, we can construct a tactile display, where the localized smooth area can be moved on the metal surface. In an experimental display employing a brass-tapered membrane vibrated by a Langevin-type ultrasonic vibrator, validity of our method is confirmed.
KIST Hybrid Master Arm
Authors: Kim Insup , Chang Sokho , Kim Jungtae , Lee Chongwon , Park Jong Oh
Published: December 2021

Formerly, we derived the concept of hybrid master arm that considers human arm characteristic and distributed muscle [1]. The hybrid master arm has human arm like configuration, which is serial globally and parallel locally and has 7 degree of freedom parallel driving mechanism.
Safe, Smooth, and Versatile Haptic Device With Large Workspace and Torque
Authors: Matsuoka Yoky , Miller Larry C.
Published: December 2021

We demonstrate a general-purpose large-workspace machine that is inherently safe and smooth. The design is targeted to allow natural whole body movements without any potential for machine induced injury. The device can be used for various applications including training athletes, rehabilitating elderly people, and large product prototyping.
A Unified Approach to Driver Assistance Systems Based on Artificial Potential Fields
Authors: Gerdes J. Christian , Rossetter Eric J.
Published: December 2021

This paper presents an approach to vehicle control based upon the paradigm of artificial potential fields. Using this method, the dynamics of the vehicle are coupled with the environment in a manner that ensures that the system exhibits safe motion in the absence of driver inputs. The driver remains in control of the vehicle, however, with the control systems presenting a predictable and safe set of dynamics. With the control approach presented here, integration of various assistance systems can be easily achieved through simple superposition of individual potential and damping functions. A simple example of a combined lanekeeping and stability system demonstrates how this can be accomplished. Preliminary simulation results suggest that both safety and driveability are achievable with such a system, prompting further investigation.
Feedback Linearizing Control of All Wheel Steered Articulated Vehicles
Authors: de Bruin D. , van den Bosch P. P. J.
Published: December 2021

This paper describes the design of an input-output linearising controller for lateral guidance of a double articulated bus with all wheel steering. Contrary to the majority of nonlinear controllers for articulated vehicles, this controller is based on a dynamic vehicle model, which is assumed to be nessecary at high velocities. Simulations under varying load conditions and for different scenarios illustrate good performance of the controller, even for large disurbances and parameter uncertainty.
Characterization of Positioning Repeatability for Systems With Variable Friction
Authors: Gilbert Douglas R. , McLain Timothy W.
Published: December 2021

Friction poses a significant challenge in precise position control. A limiting factor has been the stochastic behavior of friction and the uncertainty that it imposes on the position control problem. This paper quantifies a bound for positioning repeatability for a position control system having impulsive inputs in the presence of variable friction. The repeatability bound is defined as the smallest position error for which the probability of reducing that error is equal to fifty percent. This is the smallest error that can be repeatably reduced. A method for finding that bound is described. A nondimensional form of a servo positioning system’s state equations is used to solve for the repeatability bound in general and give insight into some design tradeoffs for servo positioning system design. Hardware experiments validate the analysis method and the existence of a repeatability bound due to frictional variation.
3D Position Sensing Using the Differences in the Time-of-Flights From a Wave Source to Various Receivers — A Conceptual Model
Authors: Mahajan Ajay , Walworth Maurice
Published: December 2021

This paper presents a novel formulation for the conceptual model for the estimation of the coordinates of a wave source based on the differences in the time-of-flights (TOFs) to various receivers fixed in 3D space. 3D position sensing using wave sources is typically done by triangulating the position of the wave source using the actual TOFs to the various receivers. There are two problems with such a formulation. The first one deals with synchronizing the wave bursts from the transmitter so as to measure the TOFs to the receivers. Further, this measured TOF incorporates delays that have to be subtracted from the measured TOFs to obtain the actual TOFs. Identification of this time delay term is the second problem. The formulation presented in this paper takes the differences in the TOFs to the various receivers, which circumvents both the problems. Typical applications that will benefit from this technology are 3D position sensing systems that may be used in robotics, navigation of autonomously guided vehicles, tracking of objects for virtual reality cells, and vibration analysis.
Adaptive Control of Flexible-Link Robots Based on a V-Shape Lyapunov Function
Authors: Lee Ho-Hoon
Published: December 2021

This paper proposes a new model-based control for flexible-link robots based on Lyapunov stability theorem, where a V-shape Lyapunov function is introduced for the flexible robot dynamics that do not satisfy the so-called matching condition. First, a new model-based nonlinear control is proposed based on a V-shape Lyapunov function, where the global exponential stability of the control is obtained. The model-based control is then extended to a model-based adaptive control to cope with parametric uncertainties in the dynamics, where the global asymptotic stability of the control is attained. The effectiveness of the proposed approach has been shown by computer simulation.
Reduced Order Finite Element Modeling of Thermally Induced Bearing Loads in Machine Tool Spindles
Authors: Gibson Alex O. , Stein Jeffrey L.
Published: December 2021

Machine tool spindle bearings are subjected to a large range of axial and radial loads due to the machining process. Further the rotating spindle must be extremely stiff to minimize the cutting tool’s deflection. The high spindle stiffness is achieved by applying a mechanical load to the bearings, the preload. In fixed preload spindles the bearing loads tend to increase with increasing spindle speed due to thermal expansion and it is well established that these thermally induced loads can lead to premature bearing failure. A model of thermally induced bearing load in angular contact bearing spindles is developed that includes an axis-symmetric reduced order finite element model of the heat transfer and thermal expansion within the spindle’s housing and shaft and the bearing and shaft dynamics. Nodal reduction is used in the reduced order model to minimize the number of temperature states and the computational load. The reduced order model’s calculated temperature and bearing load values are shown to closely match experimentally measured values over a wide range of spindle speeds. The paper ends with a parameter variation study which predicts a dramatic decrease in the thermally induced bearing load when silicon nitride balls are substituted for steel balls.
Chatter Suppression in Milling: An Active Approach
Authors: Browning Douglas R. , Golioto Igor , Thompson Norman B.
Published: December 2021

A new approach to chatter control in milling is presented in this paper. The proof-of-concept control system comprises a tool holder, analog and digital control electronics, and power amplifiers to drive the actuator elements. The active tool holder, designed to impart counter-vibration forces to the milling tool, mounts to existing machines with a standard industrial interface. Sensors and piezoelectric actuators are imbedded in the stationary portion of the tool holder and are therefore fixed relative to the body of the milling machine. The controller operates on the two sensor signals, producing two orthogonal actuator drive signals to oppose resonant tool vibrations induced from the cutting forces. The paper first introduces the fundamental concepts of milling chatter and their relation to the described active system. The actuation, sensing and controller details follow. The influence of the tool holder on system dynamics and cutting stability is also addressed. Cutting test results using a titanium alloy are then described, demonstrating an improvement of a factor of five in surface finish relative to the uncontrolled, chatter-dominated case.
Buckling and Postbuckling of Sandwich Beams With Delaminated Faces Based on Higher Order Core Theory
Authors: Li R. F. , Frostig Y. , Kardomateas G. A.
Published: December 2021

Delaminations within the face sheets are often observed when a sandwich structure is exposed to impact loads. The buckling and postbuckling behavior of sandwich beams with delaminated faces is investigated in this work. The governing nonlinear equations, boundary conditions, and continuity conditions are formulated through variational principles. The beam construction consists of upper and lower, metallic or composite laminated symmetric skins, and a soft core of a foam or low strength honeycomb type. A high order theory is used for the core that accounts for the nonlinear distortion of the plane of section of the core and the compressibility in the vertical direction. The delamination considered is an interface crack, in which the substrate includes the transversely flexible core. The case of a debond at one of the skin-core interfaces is also included. The effects of the delamination length and location on the overall and local behavior are examined with an arbitrary initial imperfection.
Determination of the Permeability Tensor of Fibrous Reinforcements for VARTM
Authors: Nedanov Pavel B. , Advani Suresh G. , Walsh Shawn W. , Ballata William O.
Published: December 2021

VARTM and SCRIMP composite manufacturing processes use a highly permeable media to distribute the resin through the thickness of the composite. Hence, manufacturing simulations of resin flow in such processes requires reliable data for in-plane as well as transverse permeability. The goal of this study is to propose a method for simultaneous determination of the principal values of 3D-permeability tensor of fibrous reinforcements. The permeability components are calculated from experimental data, consisting of flow front position with time during resin impregnation in three dimensions from a radial source under constant pressure using the SMARTweave [Walsh (1993), Fink et al.(1995)] sensor system. Experimental results are compared with numerical simulation.
A Numerical Approach to Predict the Mechanical Behaviour of Woven Fabric Composites
Authors: Riva Enrica
Published: December 2021

This paper presents a numerical tool for the design of the composites structures that allows to predict the mechanical behaviour of woven fabric composites, both in terms of global stiffness and damage process, and therefore to optimise the components dimensions and weight. Starting from an accurate study of the mesostructure of the material, finite element models are developed. To reduce the computational effort, a submodeling technique was used by employing two separate meshes: global and local meshes. Two idealised configurations are examined: they have a circular warp and fill yarn path and a lenticular cross-section. The mechanical response is estimated in terms of global stiffness and stress-strain curves of plain weave composites by simulating the damage process. The agreement between the FE global stiffness and experimental and analytical data is good. The FE results are very sensitive to the curvature of the yarns. Similar results were obtained for the FE stress-strain curves.
Optimal Design of Composite Plates Under Thermal Loads
Authors: Abrate Serge
Published: December 2021

In this article, the effect of thermal expansion on laminated composite plates are examined and the influence of the layup is studied using non-dimensional lamination parameters. A maximum of 12 parameters are needed to describe all possible laminates regardless of the number of plies. In some applications, the layup is selected to minimum thermal expansion in a certain direction. We show that thermal expansion cannot be prevented in all directions. Thermal deflections of symmetrically laminated plates that are continuous over many line supports are determined using the Rayleigh-Ritz method. The constitutive equations and the thermal loads are expressed in terms of four non-dimensional lamination parameters. Layups that minimize thermal deflections are determined for several types of composite plates subjected to temperature increases that vary linearly through the thickness.
Composite Materials in Defense: Overview and Outlook
Authors: Sloter Lewis E.
Published: December 2021

The Department of Defense maintains an annual investment of $7.4 billion in basic and applied research and advanced technology development. This investment is the foundation of future systems and operational capability and supports an annual $70 billion investment in the engineering development, testing, and acquisition of new systems. The Materials Science and Technology Program at $330 million per year forms a significant part of this investment. Currently, approximately $90 million within the Materials Program is invested in composite materials of all types. These investments are described in context of the overall Defense Science and Technology Program and with respect to the future Defense capabilities and materiel opportunities that are enabled by composite materials. Emphasis is placed on the changing nature of the Defense missions, the platforms required to meet those missions, and the role of composite materials in Defense platforms. Significant challenges posed by expected operations and acquisition needs are related to composite materials. The need for improved affordability in composite systems is discussed in terms of current projects and future challenges and outlook.
Interactive Virtual Tools for Manipulating NURBS Surfaces in a Virtual Environment
Authors: Perles Brian P. , Vance Judy M.
Published: December 2021

Virtual prototyping is the process of evaluating digital versions of designs without building physical mockups. Industry is increasingly turning to virtual prototyping in an effort to reduce design time and costs. The ability to evaluate various design configurations early in the design process using digital models allows for more opportunity to optimize the product design and explore alternate design configurations at a lower product design cost. This paper describes the development of virtual tools which give the designer the ability to take virtual prototyping one step further by allowing interactive modification to the virtual surfaces while in the virtual environment.

Virtual prototypes are created directly from computer aided design (CAD) data. Non-uniform rational B-splines (NURBS) have become the industry standard for representation of free-form curves and surfaces (Piegl, 1991). The contribution of the work presented here is in the development of virtual tools which are used to operate directly on the CAD data and change the shape of the NURBS surfaces in a virtual environment. The virtual tools can be dragged along or pushed into the surface in real-time to change its shape. The surface normal at an arbitrary point can be manipulated in three-dimensional (3D) space. Constraint-based surface manipulation is used to obtain multiple point direct manipulation of NURBS surfaces, which is not currently available in other VR CAD programs.
VPAVE: An Interactive Tool for Validating Assembly Components in Virtual Environment Using Finite Element Simulation
Authors: Deviprasad T. , Kesavadas T.
Published: December 2021

Assembly is a geometric problem and its success depends on the quality of the mating parts. Design for Assembly (DFA) takes care of the issues such as part handling, insertion and mating, and other features that make assembly an easier and cost effective task. Practical considerations like part deformation during manufacturing, wear and tear of machines and jigs, and other constraints like cost and technical limitations contribute significantly to dimensional and form errors. These factors are usually not accounted for during the DFA, as the data is not as yet available. This results in improper assembly and part rejection at a later stage. One approach of solving this problem is to develop a virtual prototype, which captures the real manufacturing variables by modeling the process impact on the assembled components. The work presented here tries to look at a few issues concerning validation of the virtual prototype (VP) of a manufactured component before assembly.

A Virtual Prototype Assembly Validation Environment dubbed VPAVE was developed to test virtual prototypes of manufactured component in a Virtual Environment for assembly process. We have demonstrated by an example that the VPAVE based validation during DFA can prevent difficulties that may arise during the actual assembly process due to the influence of the production process of the components.
A Case Study: Web Enabled Virtual Reality Robotics Training System
Authors: Teh Tuan Ann , Goh Yuan Sheng Victor
Published: December 2021

Virtual Reality Robotics Training System is the use of desk-top Virtual Reality (VR) system for preparing a user to operate on a real robotics system. The computer system presents the user with a view of a virtual robotics system. The virtual world replicates actions of the actual robotics system. The view will be a 3D scene and a user can immerse in this virtual world by wearing a Head Mounted Display. As the user of system, he can move around a virtual robotics system through the use of foot switches, go to a particular view of the system and operate or control it just like the real machine. A virtual teach pendant will appear and the machine can be operated individually by activating the contact buttons of the pendant using a trackball. All sound normally heard in the operation of the actual system is replicated so that the user would be able to tell both visually as well as aurally if the actions are correct. With Internet fast moving towards full 3D multimedia, interactive platform, it is possible to link the virtual world to the real physical system and place the virtual world on the Internet so that user can control, operate, and manipulate the physical system remotely. This paper investigates the possibility of using such a virtual training system without having to invest on an actual system but achieving the same training effectiveness as the actual system. It also describes how the training system could be remotely operated using Virtual Reality technology through a platform independent, Internet enabled graphical user interface with real time video feedback. Possible applications of this case study include tele-control of robot in hazardous environments, remote diagnosis of manufacturing systems, tele-manufacturing and high value-added training.
A Generic Template for Collaborative Product Development
Authors: Zhang Jiyu , Chen Jie , EL-Mounayri Hazim
Published: December 2021

A generic template system is presented in this paper. The template, which is basically a management system and an integration platform, adopts virtual prototyping, cross-functional teaming and information integration to improve the performance of product development life cycle. The architecture and working principles of the template are discussed. This architecture provides a collaborative environment for product development aiming at integrating people, process and data in the complete product development cycle. Also, a new integration strategy, that adopts PDM as its universal integration platform, is proposed and realized. This strategy reduces the requirements of integrating a software module (or “a virtual model”) into the template to only the development of the interface between this module and the PDM. In addition, the generic template contains methods and mechanisms to create and maintain virtual prototyping models for different engineering products and engineering systems that involve mechanical as well as electrical components (e.g. a power train). Currently, the template includes sufficient models to accurately and reliably model, simulate and evaluate complete engineering systems. Some of these models do not exist in the current state-of-the-art commercial CAD/CAE/CAM/PDM systems.
Numerical Prediction of Noise Radiated From a Panel Subjected to Boundary Layer Excitation
Authors: Allen Michael , Vlahopoulos Nickolas
Published: December 2021

In this paper an algorithm is developed for combining finite element analysis and boundary element techniques in order to compute the noise radiated from a panel subjected to boundary layer excitation. The excitation is presented in terms of the auto and cross power spectral densities of the fluctuating wall pressure. The structural finite element model for the panel is divided into a number of sub-panels. A uniform fluctuating pressure is applied as excitation on each sub-panel separately. The corresponding vibration is computed, and is utilized as excitation for an acoustic boundary element analysis. The acoustic response is computed at any data recovery point of interest. The relationships between the acoustic response and the pressure excitation applied at each particular sub-panel constitute a set of transfer functions. They are combined with the spectral densities of the excitation for computing the noise generated from the vibration of the panel subjected to the boundary layer excitation. The development presented in this paper has the potential of computing wind noise in automotive applications, or boundary layer noise in aircraft applications.
Acoustic Computations Using Incompressible, Inviscid CFD Results as Input
Authors: Grace Sheryl M. , Curtis Caroline K.
Published: December 2021

This paper presents preliminary results from an acoustic post processor for incompressible, viscous computations. The method is applied to the two-dimensional problem of grazing flow past a cavity. A research RANS code is used to obtain the incompressible flow field quantities. Subsequently, the acoustic calculation is performed using a second-order finite-difference scheme. The method is shown to be a viable strategy for obtaining predictions for the acoustic field associated with a viscous, subsonic flow.