bluuebunny/crossref_metadata_2025 huggingface dataset:
Food allergy treatment value: Child caregiver and patient perspectives
Authors: Abdelwadoud Moaz , Eftekhari Sanaz , Jaffee Hannah , Carver Melanie , Mattingly T. Joseph
Published: February 2021

Background

Food allergy is a major health problem that significantly impacts quality of life (QoL). There is growing focus to evaluate food allergy‐related QoL and treatment options’ value beyond the clinical effectiveness perspective by engaging patients and caregivers. We aimed to identify and prioritize outcomes important to food allergy parents of children and patients allergic to milk, egg, and/or peanut, to guide comparative effectiveness research (CER) that focuses on evaluating food allergy treatment decisions.

Methods

We conducted a modified 3‐round Delphi study to identify and derive consensus on priority treatment outcomes for parents of children and adult patients with diagnosed allergies to at least one of three major allergenic foods (milk, egg, and peanut) from across the United States.

Results

Round 1 yielded 44 statements for round 2, and 39 statements reached the agreement level for round 3 ranking. Statements were organized under 4 sections: 1) food allergy problems, 2) treatment experiences, 3) important treatment outcomes, and 4) value of different treatment options.

Conclusion

Food allergy parents and patients face several social, psychological, medical, healthcare, financial, food selection, and awareness challenges. The areas of consensus on important treatment outcomes revealed shared priority for reducing the risk of potentially fatal allergic reactions and having reliable treatments. The most valued treatment options reflect hope for permanent cure and fear of serious allergic reactions.
Exogenous pipecolic acid modulates plant defence responses against Podosphaera xanthii and Pseudomonas syringae pv. lachrymans in cucumber (Cucumis sativus L.)
Authors: Pazarlar S. , Sanver U. , Cetinkaya N.
Published: February 2021

Systemic acquired resistance (SAR) is a long‐lasting and broad‐based resistance that can be activated following infection with (a)virulent pathogens and treatment with exogenous elicitors. Pipecolic acid (Pip), a Lys‐derived non‐protein amino acid, naturally occurs in many different plant species, and its N‐hydroxylated derivative, N‐hydroxypipecolic acid (NHP), acts as a crucial regulator of SAR.

In the present study, we conducted a systemic analysis of the defence responses of a series of D,L‐Pip‐pretreated Cucumis sativus L. against Podosphaera xanthii (P. xanthii) and Pseudomonas syringae pv. lachrymans (Psl). The effects of D,L‐Pip on ROS metabolism, defence‐related gene expression, SA accumulation and activity of defence‐related enzymes were evaluated.

We show that exogenously applied D,L‐Pip successfully induces SAR in cucumber against P. xanthii and Psl, but not Fusarium oxysporum f. sp. cucumerinum (Foc). Exogenous application of D,L‐Pip via the root system is sufficient to activate the accumulation of free and conjugated salicylic acid (SA), and earlier and stronger upregulation of SAR‐associated gene transcription upon P. xanthii infection. Furthermore, D,L‐Pip treatment and subsequent pathogen inoculation promote hydrogen peroxide and superoxide accumulation, as well as Rboh transcription activation in cucumber plants, suggesting that D,L‐Pip‐triggered ROS production might be involved in enhanced defence reactions against P. xanthii. We also demonstrate that D,L‐Pip pretreatment increases the activity of defence‐associated enzymes, including peroxidase, chitinase and β‐1,3‐glucanase.

The results presented in this report provide promising features of Pip as an elicitor in cucumber and call for further studies that may uncover its potential in production areas against different phytopathogens.
The Rhetoric of the Trump Administration
Authors: Stuckey Mary E.
Published: February 2021

By extending the personalized presidency from the institution to the individual president while undercutting the bureaucracy's reliance on expertise and by attacking democratic norms and values, Donald Trump undermined both the executive as an institution and his own ability to govern. These elements of his presidential rhetoric are clarified with reference to Trump's relationships with the media, the executive branch, and the mass public, and are distilled in his handling of the global pandemic.
Instructed reappraisal and cardiovascular habituation to recurrent stress
Authors: Griffin Siobhán M. , Howard Siobhán
Published: February 2021

Instructed reappraisal has previously been associated with a challenge‐oriented cardiovascular response profile, indexed by greater cardiac output (CO) and lower total peripheral resistance (TPR), in response to asinglestress exposure. The present study builds on this research by employing a stress habituation paradigm where participants completed a speech task twice; in which prior to the second task participants heard reappraisal instructions (i.e., view feelings of stressarousalas something that is beneficial) or control instructions. This paradigm allowed us to (a) test if reappraisal aids cardiovascular habituation torecurrentstress, and (b) examine if reappraisal leads to a within‐participant change in CO/TPR responding from an uninstructed task to an instructed reappraisal task. Habitual use of reappraisal was assessed using the Emotion Regulation Questionnaire. The analyses report upon 173 young adults (121 women, 52 men). Cardiovascular parameters were measured continuously using the Finometer Pro. All participants demonstrated similar cardiovascular habituation during the second stress exposure (lower SBP, CO, and HR); suggesting that reappraisal did not aid cardiovascular habituation to recurrent stress. Reappraisal instructions did not lead to a challenge‐oriented response compared to both the control group and responses to the uninstructed task. This study is the first to examine the relationship between instructed reappraisal and cardiovascular habituation and identifies that habitual use of reappraisal does not interact with reappraisal instructions to influence cardiovascular responses to stress.
Anatomy of a mixed bioclastic–siliciclastic regressive tidal sand ridge: Facies‐based case study from the lower Pleistocene Siderno Strait, southern Italy
Authors: Longhitano Sergio G. , Rossi Valentina M. , Chiarella Domenico , Mellere Donatella , Tropeano Marcello , Dalrymple Robert W. , Steel Ronald J. , Nappi Antonio , Olita Fabio
Published: February 2021

Sand ridges, a common feature of modern open shelves, reflect persistent currents and sediment availability under recent transgressive conditions. They represent the largest bedforms in the oceans and, as such, can yield information on long‐term oceanographic processes. However, there is a limited number of tidal sand ridges documented from the rock record, examples of regressive tidal sand ridges are scarce and studies describing ridges in straits are even more rare. This study analyses a Gelasian succession within a structurally controlled, tide‐dominated strait in the Siderno Basin, southern Italy. The strait connected two wider basins, and accumulated sediments reworked by amplified tidal (bi‐directional) currents. A series of tidal sand ridges with superimposed dunes developed close to the south‐eastern end of the strait, where bathymetry was deeper and flow expansion occurred. One of the best‐exposed tidal sand ridges, 65 m thick, crops out along a ca 2 km long cliff. Large‐scale, ESE‐prograding, seaward‐offlapping shingles contain sets of bioclastic–siliciclastic, coarse‐grained, cross‐stratified sandstones, erosionally overlying upper Pliocene shelf marls and fine‐grained sandstones. Cross‐strata show angular, tangential and sigmoidal foresets with compound architectures and a SSE migration, i.e. oblique to the main growth direction. Fossil content indicates open‐marine conditions. The succession changes abruptly across an erosion surface to non‐tidal, highly burrowed mixed siliciclastic–bioclastic fine‐grained sandstones, less than 15 m thick. Documented features reflect stages of nucleation, active accretion and abandonment of an individual sand ridge, during a complete cycle of relative sea‐level change. The ridge formed during a phase of normal regression, with accretion occurring during an initial highstand and the ensuing falling stage. During the lowstand the ridge was split into several minor bodies by enhanced tidal currents. The ensuing transgression draped the moribund ridge with tabular strata, whereas final highstand shelf sedimentation reworked the top of the underlying sand body with weak currents.
Preliminary test estimation in uniformly locally asymptotically normal models
Authors: Paindaveine Davy , Rasoafaraniaina Joséa , Verdebout Thomas
Published: February 2021

Preliminary test estimation is a methodology that combines goodness‐of‐fit testing and estimation. It is a classical procedure when it is suspected that the parameter to be estimated satisfies some prespecified constraints. In the present paper, we establish general results on the asymptotic behavior of preliminary test estimators. More precisely, we show that, in uniformly locally asymptotically normal (ULAN) models, a general asymptotic theory can be derived for preliminary test estimators based on estimators admitting generic Bahadur‐type representations. This allows for a detailed comparison between classical estimators and preliminary test estimators in ULAN models. Our results, that, in standard linear regression models, are shown to reduce to some classical results, are also illustrated in more modern and involved setups, such as the multisample one where m covariance matrices  are to be estimated when it is suspected that these matrices might be equal, might be proportional, or might share a common “scale”. Simulation results confirm our theoretical findings and an illustration on a real data example is provided.
When Color‐conscious Meets Color‐blind: Millennials of Color and Color‐blind Racism
Authors: Cox Jonathan M.
Published: February 2021

Most contemporary research suggests that white Americans overwhelmingly subscribe to color‐blind racial ideology; however, comparatively little is known about people of color. What is less known, however, is how color‐blindness is used by nonwhites: most existing work on color‐blindness and people of color (POC) focuses exclusively on African Americans, or investigates specific circumstances like interracial relationships. This current project helps to fill some of the gaps in current knowledge regarding nonwhites and color‐blindness by investigating how nonwhites utilize or reject color‐blind racial ideology. To this end, I analyze personal journals and interviews with 48 Latinx, Asian, black (including ethnically black), and multiracial college Millennials in order to understand how their racial and ethnic identities impact their ideological beliefs. Findings suggest that Millennials of color use color‐blindness infrequently as compared to their white peers, and their usage is very nuanced, inconsistent, and often contradictory. I discuss how POC are often bound by the dominant racial ideology of the U.S., such that it colors their perceptions largely through indirect means.
Characterization of the novel allele HLA‐DRB1*01:01:36 in an Emirati donor
Authors: Alvares Marion , Al Mahri Ayeda , Jannang Raysha , Al Yafei Zain , ElGhazali Gehad
Published: February 2021

HLA‐DRB1*01:01:36 is a variant of DRB1*01:01:01, differing by three single nucleotide substitutions.
Characterization of the novel HLA‐DQA1*05:18 allele by next‐generation sequencing
Authors: Genebrier Steve , Rouzaire Paul , Texeraud Emeric , Bertrand Gerald , Renac Virginie
Published: February 2021

DQA1*05:18 differs from DQA1*05:01:01:03 by one nucleotide substitution at position 94 in exon 2.
Plant stem cell research is uncovering the secrets of longevity and persistent growth
Authors: Umeda Masaaki , Ikeuchi Momoko , Ishikawa Masaki , Ito Toshiro , Nishihama Ryuichi , Kyozuka Junko , Torii Keiko U. , Satake Akiko , Goshima Gohta , Sakakibara Hitoshi
Published: February 2021

Plant stem cells have several extraordinary features: they are generated de novo during development and regeneration, maintain their pluripotency, and produce another stem cell niche in an orderly manner. This enables plants to survive for an extended period and to continuously make new organs, representing a clear difference in their developmental program from animals. To uncover regulatory principles governing plant stem cell characteristics, our research project ‘Principles of pluripotent stem cells underlying plant vitality’ was launched in 2017, supported by a Grant‐in‐Aid for Scientific Research on Innovative Areas from the Japanese government. Through a collaboration involving 28 research groups, we aim to identify key factors that trigger epigenetic reprogramming and global changes in gene networks, and thereby contribute to stem cell generation. Pluripotent stem cells in the shoot apical meristem are controlled by cytokinin and auxin, which also play a crucial role in terminating stem cell activity in the floral meristem; therefore, we are focusing on biosynthesis, metabolism, transport, perception, and signaling of these hormones. Besides, we are uncovering the mechanisms of asymmetric cell division and of stem cell death and replenishment under DNA stress, which will illuminate plant‐specific features in preserving stemness. Our technology support groups expand single‐cell omics to describe stem cell behavior in a spatiotemporal context, and provide correlative light and electron microscopic technology to enable live imaging of cell and subcellular dynamics at high spatiotemporal resolution. In this perspective, we discuss future directions of our ongoing projects and related research fields.
Daratumumab for delayed RBC engraftment following major ABO mismatched haploidentical bone marrow transplantation
Authors: Yates Bonnie , Molloy Eoghan , Dulau‐Florea Alina , Braylan Raul , Hogan Laura , Hickstein Dennis D. , Freeman Alexandra F. , Kalsi Shelley S. , Shah Nirali N.
Published: February 2021

Background

Recent case reports have described the efficacy of daratumumab to treat refractory pure red cell aplasia (PRCA) following major ABO mismatched allogeneic hematopoietic stem cell transplantation (HSCT). In this report, we describe the use of daratumumab as a first‐line agent for treatment of delayed red blood cell (RBC) engraftment following a major ABO mismatched pediatric HSCT and provide a review of the literature.

Study Design and Materials

We report on a 14‐year‐old with DOCK8 deficiency who underwent a myeloablative, haploidentical bone marrow transplant from her major ABO mismatched sister (recipient O+, donor A+) for treatment of her primary immunodeficiency. Despite achieving full donor chimerism, she had delayed RBC engraftment requiring ongoing transfusions. Due to iron deposition, symptomatic anemia, and persistence of anti‐A iso‐hemagglutinins despite discontinuation of immunosuppression, treatment for delayed RBC engraftment with the CD38‐targeted monoclonal antibody daratumumab was selected as a less immunosuppressive agent that could more selectively target iso‐hemagglutinin producing plasma cells without causing broad B‐cell aplasia.

Results

Clinical effect with daratumumab was demonstrated by reduced iso‐hemagglutinin titer, increased reticulocytosis, normalization of her hemoglobin, and transfusion independence. In the 11‐month follow‐up period to date, no additional transfusions or immunosuppression have been necessary, despite persistence of low‐level anti‐A iso‐hemagglutinin.

Conclusion

Our experience suggests that daratumumab was an effective first‐line therapy for delayed RBC engraftment and that earlier consideration for daratumumab in treatment of delayed RBC engraftment may be warranted.
Eighty-Five Percent of Improved Optical Power Delivery to Epiretinal Prostheses Using Rigid Body Compensation Algorithm
Authors: Mailhot Nathaniel , Cheriton Ross , Vyas Kaustubh , Cook John , Prawer Steven , Hinzer Karin , Spinello Davide
Published: February 2021

Vision impairment caused by degenerative retinal pathologies such as age-related macular degeneration can be treated using retinal implants. Such devices receive power and data using cables passing through a permanent surgical incision in the eye wall (sclera), which increases the risk to patients and surgical costs. A recently developed retinal implant design eliminates the necessity of the implant cable using a photonic power converter (PPC), which receives optical power and data through the pupil and is directed by an ellipsoidal reflector and micro-electromechanical mirror. We present a misalignment compensation algorithm model that accounts for rigid-body motions of the reflector relative to the eye and applies the correction to the mirror coordinates in the presence of angular misalignment of the reflector. We demonstrate that up to 85% of the nominal optical power can be delivered to the implant with axial reflector misalignments up to 30 deg using the compensation algorithm.
Quasi-Linear Viscoelastic Characterization of Soft Tissue-Mimicking Materials
Authors: Helisaz Hamed , Bacca Mattia , Chiao Mu
Published: February 2021

We present a novel method based on the quasi-linear viscoelastic (QLV) theory to describe the time-dependent behavior of soft materials. Unlike previous methods for deriving QLV parameters, we characterize the elastic and viscous behavior of materials separately by using two different sets of experiments. To model the nonlinear elastic behavior, we fit the elastic stress response with a one-term Ogden model. Then, we model the relaxation behavior with a Prony series to compare the stress relaxation of the material at different timescales. This new method allows us to characterize materials with narrow confidence intervals (high accuracy), independently from the loading conditions. We validate our model using samples made of phantom materials that mimic normal and cancerous prostate tissues in terms of Young's modulus. Our model is shown to distinguish materials with similar elastic (viscous) properties but different viscous (elastic) properties. Drawing a precise distinction between the phantoms, this method could be useful for prostate cancer (PCa) diagnosis; but significant clinical studies will be needed in the future.
Colored Lévy Noise-Induced Stochastic Dynamics in a Tri-Stable Hybrid Energy Harvester
Authors: Zhang Yanxia , Jin Yanfei
Published: February 2021

The piezoelectric and electromagnetic hybrid vibration energy harvester (HVEH) has proven to be a favorable option to deal with the low power generation issue and overcome the drawbacks of each individual transduction mechanism. Besides, colored Lévy noise consisting of small perturbations, large jumps, and correlation time turns out to be a relatively suitable tool for describing the complex environments. For the purpose of enhancing the harvesting performance of HVEH, the stochastic dynamics induced by colored Lévy noise in a tri-stable HVEH is mainly investigated in this paper. The stationary probability density, the largest Lyapunov exponent, the signal-to-noise ratio, and the mean harvested power are calculated to explore the stochastic dynamics of system, such as the stochastic response, the stochastic stability, the stochastic resonance (SR), and the energy harvesting performance. The results show that the colored Lévy noise can induce stochastic P-bifurcation, D-bifurcation, and SR phenomenon. In particular, the comparisons between colored Lévy noise and colored Brownian noise in dynamics and harvesting performance are also discussed in detail. It is found that the colored Lévy noise can make a greater contribution than colored Brownian noise in the effective voltage and help to improve the mean harvested power through the SR effect.
Spray Cooling on Enhanced Surfaces: A Review of the Progress and Mechanisms
Authors: Xu Ruina , Wang Gaoyuan , Jiang Peixue
Published: February 2021

The rapid development of high-power electronic, energy, and propulsion systems has led us to the point where the performances of these systems are limited by their cooling capacities. Current electronics can generate heat fluxes up to 10–100 W/cm2, and heat flux over 1000 W/cm2 needs to be dissipated with a minimum coolant flow rate in next-generation power electronics. The multiple efficient heat transfer mechanisms have made spray cooling a high heat flux, uniform and efficient cooling technique proven effective in various applications. However, the cooling capacity and efficiency of spray cooling need to be further improved to meet the demands of next-generation ultrahigh-power applications. Engineering of surface properties and structures, which is enabled by state-of-the-art manufacturing techniques, can fundamentally affect the liquid–wall interactions in spray cooling, thus becoming the most promising way to enhance spray cooling. However, the mechanisms of surface-enhanced spray cooling are diverse and ambiguous, causing a lack of clear guiding principles for engineered surface design. Here, the progress in surface engineering-enhanced spray cooling is reviewed for surface structures of millimeter, micrometer, and nanometer scales and hierarchical structured surfaces, and the performances from the reviewed literature are evaluated and compared. The reviewed data show that spray cooling can achieve a critical heat flux (CHF) above 945.7 W/cm2 and a heat transfer coefficient (HTC) up to 57 W/cm2K on structured surfaces without the assistance of secondary gas flow and a CHF and an HTC up to 1250.1 W/cm2 and 250 W/cm2K, respectively, on a smooth surface with the assistance of secondary gas flow. A CHF enhancement up to 110% was achieved on a hybrid micro- and nanostructured surface. A clear map of enhancement mechanisms related to the scales of surface structures is proposed, which can help the design of engineered surfaces in spray cooling. Some future concerns are proposed as well. This work helps the understanding and design of engineered surfaces in spray cooling and provides insights for interdisciplinary applications of heat transfer and advanced engineering materials.
Understanding Capacity Sensitivity of Cooled Transonic Nozzle Guide Vanes: A Parametric Experimental and Computational Study of the Impact of Trailing Edge Geometry
Authors: Burdett Daniel , Goenaga Frédéric , Povey Thomas
Published: February 2021

High-pressure (HP) nozzle guide vane (NGV) capacity is one of the most important parameters for setting overall turbine power output, for stage matching, and for understanding turbine performance. Accurate capacity prediction early in the engine design process reduces the cost and risk of late-stage changes in the overall turbine design. High accuracy predictions rely on calibrated computational fluid dynamics (CFD) methods. Because of the numerous sensitivities in the methods, they are generally restricted to certain classes of design for which there is experimental validation. This paper considers the effect of changes in trailing edge (TE) geometry—particularly suction side (SS) TE overhang length—on the flow capacity of a modern HP NGV. Ultra-low uncertainty experimental measurements and complementary numerical predictions of capacity are presented for four TE geometries, in a parametric study bridging the gap between a classical centered-ejection design and a SS overhang TE design. This study discusses the absolute and relative (differences between designs) accuracies of the numerical method and develops understanding of the sensitivity of capacity to TE geometry. Fundamental mechanisms responsible for the observed capacity changes are elaborated. The impacts on capacity of both changes in the coolant flows and the boundary layers in the controlling region of the vane passage are considered. These effects are found to be very small. A simple total pressure loss model was also developed but was found to be a poor predictor of the observed capacity changes across the entire range of overhang lengths. To understand the observed changes, two more sophisticated models of the vane passage are proposed. In the first model—for relatively long TE overhangs—the mainstream and TE flows (and a wake) pass through a common minimum area. In the second model—for relatively short TE overhangs—the two flows are considered to pass through independent, non-interacting minimum areas. This framework reconciles the experimental and numerical data with the models but illustrates the complexity of the problem. In particular, it demonstrates the arbitrariness of considering a single minimum area. Contrary to some received industrial wisdom, it is argued that deemphasising this construct, and explaining capacity changes by examining aerodynamic changes in the entire controlling region of the passage, is more helpful in attempting to understand design sensitivities.
Generating Compressive Surface Residual Stresses Using Hydraulic Autofrettage Process With Heat Treatment
Authors: Shufen Rajkumar , Dixit Uday S.
Published: February 2021

Recently, a method of inducing compressive residual stresses in the vicinity of the walls of a thermally autofrettaged cylinder was proposed. In the proposed method, the thermally autofrettaged cylinder was heated in such a manner that its outer wall attained a temperature more than the lower critical temperature and the inner wall was at a sufficiently lower temperature. When the cylinder was quenched, compressive residual stresses were induced in the vicinity of the cylinder walls. This article investigates the feasibility of the same procedure for a hydraulic-autofrettaged cylinder made of AISI 1080 steel. A finite element method (FEM)-based analysis is carried out using commercial package abaqus by incorporating microstructure and temperature-dependent material properties. The results indicate that the heat treatment design proposed for the thermally autofrettaged cylinder to induce compressive residual stresses at the outer wall can also be adapted for a hydraulic-autofrettaged cylinder. However, for cylinders subjected to high percentage of autofrettage, heating of the outer wall needs to be carried out well below the lower critical temperature. In fact, this is an advantage in terms of energy saving and can be implemented even for cylinders subjected to a low percentage of autofrettage.
Numerical Assessment of Elbow Element Response Under Internal Pressure
Authors: Attia Saher , Mohareb Magdi , Martens Michael , Yoosef-Ghodsi Nader , Li Yong , Adeeb Samer
Published: February 2021

This study presents a detailed assessment for the response of elbow elements in ABAQUS under internal pressure. Two main cases are considered: (1) a standalone 90 deg pipe bend, which was analyzed using both elastic and elasto-plastic material characterizations using shell and elbow elements; and (2) a geometrically nonlinear analysis with a materially elastic characterization of a piping system was conducting using shell, elbow, and pipe elements. Although the results show the capabilities of elbow elements to simulate the response of pipe bends in the elastic regime, the elements do not provide reliable predictions beyond the elastic range. Additionally, an assessment of the ASME B16.49 2017 elbow thickness equation and previously published stress estimate equations was carried out by comparisons with elbow and shell elements predictions.
Design Framework and Clinical Evaluation of a Passive Hydraulic Patient Simulator for Biceps Spasticity Assessment Training
Authors: Pei Yinan , Ewoldt Randy H. , Zallek Christopher M. , Hsiao-Wecksler Elizabeth T.
Published: February 2021

This article presents the framework for developing a passive (unpowered) mechanical training simulator for replication of biceps spasticity to complement current clinical assessment training. The passive training simulator was developed to mimic three main behavioral features of spasticity, i.e., abnormal muscle tone, catch-release behavior, and range of motion (ROM) reduction. The simulator can replicate varied levels of spasticity (Modified Ashworth Scale (MAS) levels 0–4) using a combination of three adjustable mechanical design features, i.e., resistance level, catch angle, and ROM selectors. Bench-top evaluation examined the performance of individual mechanical design features, as well as their combined performance. Spastic muscle resistance profiles generated by the simulator qualitatively agreed with the clinical descriptions of spasticity in the MAS. Mean peak simulated resistive torque fell within the clinical measures from actual spasticity patients for MAS 1–4, but was lower for MAS 0 (0.9, 3.5, 4.2, 6.9, 9.8 Nm for MAS 0–4, respectively). Seven clinicians were invited to validate the simulator performance. They were asked to identify the simulated MAS level during a blinded assessment and to score the realism of each simulation feature using a five-point scale, where 3 was “about right,” during a disclosed assessment. The mean percent agreement of clinicians’ judgments was 76 ± 12%. The mean realism score throughout MAS 0–4 were 2.82 ± 0.15. Preliminary results suggested good potential for this simulator in helping future healthcare practitioners learn and practice the basics of spasticity assessment.
Virtual Reality for Power Plant Design
Authors: Ebbesmeyer Peter , Gehrmann Peter , Grafe Michael , Krumm Holger
Published: February 2021

We describe DesiRe, a Design Review system based on virtual reality technology. DesiRe is a production virtual reality system that is used to support design review processes during the development of The European Pressurized Water Reactor (EPR). This paper starts with a brief description of the EPR project. We then focus on the design review processes that are an important part of the EPR development processes. We discuss why the use of virtual reality technology significantly improves the design review processes. The subsequent part of the paper introduces in detail the implementation issues and application issues of the virtual reality system DesiRe currently being used by the EPR engineers in their design review meetings. The end of the paper gives an outlook on future work and a brief conclusion. The work presented in this paper is part of an ongoing virtual reality research project at the Heinz Nixdorf Institut and Siemens AG KWU.
Constraint-Based Virtual Environment for Supporting Assembly and Maintainability Tasks
Authors: Fernando Terrence , Wimalaratne Prasad , Tan Kevin
Published: February 2021

This paper presents the design and implementation of a constraint-based virtual environment for supporting interactive assembly and maintenance tasks. The system architecture of the constraint-based virtual environment is based on the integration of components such as OpenGL Optimizer, Parasolid geometric kernel, a Constraint Engine and an Assembly Relationship Graph (ARG). The approach presented in this paper is based on pure geometric constraints. Techniques such as automatic constraint recognition, constraint satisfaction, constraint management and constrained motion are employed to support interactive assembly operations and realistic behaviour of assembly parts. The current system has been evaluated using two industrial case studies. This work is being carried out as a part of a research programme referred to as IPSEAM (Interactive Product Simulation Environment for Assessing Assembly and Maintainability), at the University of Salford.
Machining Feature Recognition for Cast Then Machined Parts
Authors: Kim Yong Se , Wang Eric
Published: February 2021

We present a method to recognize machining features for the domain of cast-then-machined parts. Non-interacting volumetric machining features are recognized through a face pattern based recognition approach, and are filtered out of the part model. From the filtered part model and the specification of part surfaces as being cast or machined, we systematically generate the surface machining features and the starting workpiece, which represents the casting output in sufficient detail to support machining process planning. By subtracting the filtered part from its starting workpiece, we obtain the removal volume that is to be realized through machining operations. We apply the feature recognition method using Alternating Sum of Volumes With Partitioning (ASVP) Decomposition to decompose this removal volume into volumetric machining features.
Automatic Model Adjustment in Form Feature Conversion
Authors: Noort Alex , Bronsvoort Willem F.
Published: February 2021

A problem with multiple-view form feature modelling is that, sometimes, a feature model cannot be derived for some view of a product. This indicates that the product, as it is, is not appropriate seen from the product development phase related to that view. In such a case, the product model should be adjusted such that a feature model for the view becomes possible.

A method is presented in which, if possible, the product model is automatically adjusted. The adjustment is based on information on the importance of properties of the model, and on information on the dependencies between the shape faces. After the model has been adjusted, a feature model of the new view is derived.
The Portable CMM in Reverse Engineering
Authors: Perreault Dan , Ward Matthew
Published: February 2021

Reverse Engineering is the process of documenting data from existing parts such that those parts can be reproduced. This data can be as simple as obtaining a few dimensions, or as complex as producing a fully enclosed 3D surface model.
Component-Commonality via Hierarchical Orthogonal Arrays and Refining: Economic Decision Matrices
Authors: Majerus J. N. , Smith R. P. , Yao S. M.
Published: February 2021

Component-Commonality implies products using many common parts, desensitized to the range of product applications (defined as noise in this approach), and meeting the functionality objectives of each product. This paper presents a methodology for developing common components and applies it to a sample problem Basically, the methodology involves nine sequential steps. These steps utilize the major concepts of analytical modeling, economic decision matrices (EDM), quality Loss-functions (QLS) for variates and weighted utilities, stochastic models, finite element (FE) simulations for concurrent engineering, and statistical experiments for considering the uncertainty in either application, statistics or managerial decisions. In this paper, the statistical experiments utilize Taguchi’s orthogonal arrays (TOA). The details of these steps are illustrated by application to a problem involving a slider-link subjected to a wide range of noise (inertia/pressure loadings). Six candidate-designs of steel, aluminum and titanium, are generated using an analytical model and a sensitivity study with sequential TOA. These designs are ranked using cost and weight and factor-of-safety with respect to yielding, A Refining EDM with a three part robustness criteria (RC) selected two candidates (best was steel, followed by aluminum) considering Inner noise in the managerial decisions. Verification of the Refining EDM model via a Detailing EDM with a stochastic model and FE simulations is presented in a companion paper.
Automatic Step-Size Procedure in Forward-Difference for Reliability and Design Optimization
Authors: Wang Liping , Gau Kristy
Published: February 2021

In this paper, an improved automatic step-size procedure in forward-difference approximation for reliability analysis and optimization design is proposed. Traditionally, the step-size is pre-selected and does not change during optimization / reliability design process. This fixed step-size procedure may provide “poor” derivative approximations for highly nonlinear problems or the problems having insufficient digits of the outputs. The proposed method computes the optimum step size for each design variable by minimizing the truncation and condition errors. The condition error is focused on the error caused by insufficient digits of the outputs in this paper. Several numerical problems are tested to demonstrate the proposed procedure. The results comparison shows that the proposed procedure provides more accurate gradients for optimization and reliability design.
Serial 5DOF Manipulators: Workspace, Void, and Volume Determination
Authors: Abdel-Malek K. , Yeh Ham-Jou , Khairallah Nada
Published: February 2021

Algorithms for identifying closed form surface patches on the boundary of 5DOF manipulator workspaces are developed and illustrated. Numerical algorithms for the determination of three- and four-DOF manipulator workspaces are available, but formulations for determining equations of surface patches bounding the workspace of five-DOF manipulators were never presented. In this work, constant singular sets in terms of the generalized variables are determined. When substituted into the vector function yield hyperentities that exist internal and external to the workspace envelope. The appearance of surfaces parametrized in three variables within the workspace requires further analysis pertaining to a coupled singular behavior and is also addressed. Previous results pertaining to bifurcation points that were unexplained are now addressed and clarified. Numerous examples are presented.
The Analysis of Forward/Inverse Force Transmission Capabilities of the Stewart Platform
Authors: Kim Han Sung , Choi Yong Je
Published: February 2021

The statics relation of the Stewart platform has been investigated from the viewpoint of the forward/inverse force transmission capabilities. Two eigenvalue problems corresponding to the forward and inverse force transmission analyses have been formulated. The forward force transmission analysis is to determine the magnitude bounds of the force and moment generated at the end-effector for the given magnitude of actuating forces. Conversely, the inverse force transmission analysis is to find the magnitude bound of actuating forces for the given magnitudes of the force and moment at the end-effector. The inverse force transmission analysis is important since it can provide a designer with valuable information about how to choose the linear actuators. It has been proved that the two eigenvalue problems have a reciprocal relation with each other, which implies that solving either of the eigenvalue problems may complete the forward and inverse force transmission analyses. A numerical example is also presented.
A Study of Constraint Management Integration Into the Conceptual Design Phase
Authors: Yusan Hakan , Rudolph Stephan
Published: February 2021

Constraint management integration into the conceptual design phase is a key step towards a future support tool for engineering design. The use of graph theory in constraint management, where the design models are presented as constraints between the design parameters, provides a means for the automation of the solution path of the conceptual design equations. The generation of a solution path simplifies the study of the couplings between design parameters and the subsequent sensitivity analysis. Based on the so-called relevance list of the constraints, the approach is even applicable in design cases, where an explicit mathematical model of the constraints is not available or known.

The paper presents a constraint management system currently under implementation. As an extension to previous works, the symbolic processing capabilities of Maple V are used along the solution path to generate a C-code of the known constraint equations to further ease the design space exploration and subsequent design optimization efforts. Some theoretical and practical problems associated with the management of analytical constraints and the information flow in the different processing stages are described and discussed using a simplified design example.
Stable Assembly Sequence Planning Using a Genetic Algorithm
Authors: Chen Shiang-Fong , Liao Xiao-Yun
Published: February 2021

Stability problems in assembly sequence planning have drawn great research interest in recent years. Most proposed methodologies are based on graph theory and involve complex geometric and physical analyses. As a result, even for a simple structure, it is difficult to take all the criteria into account and to implement real world solutions. This paper uses a genetic algorithm (GA) to synthesize different criteria fo generating a stable assembl plan. Three matrices (Connection Matrix, Supporting Matrix, and Interference-Free Matrix) are generated from an input B-rep file to represent the CAD information of a given product. The stability of a given assembly plan and reorientation numbers are incorporated into the fitness function of the genetic assembly planner. The proposed planning algorithm has been successfull implemented. This paper also presents implemented planne performance as measured for two industry-standard structures.
Methods and Principles for Concurrent Functional Tolerance Design
Authors: McAdams Daniel A. , Wood Kristin L.
Published: February 2021

In this paper, a concurrent functional tolerance design process is presented. The field of tolerance research is briefly reviewed to determine the new developments needed for a complete set of concurrent tolerance design tools. Motivated by this approach, the novel notion of metamorphosis for tolerance design is introduced and developed. Customer motivated techniques for determining component functional tolerances are developed. Also, principles of tolerance design are presented and demonstrated. The developed principles are clarified and validated through an original design case study of an electric guitar pickup (electromagnetic transducer) winder. The paper concludes with a discussion of the extensions of this work and future needs for tolerance design research.
Visualizing Sequential Information With Perceptual Cues
Authors: Dansie Christopher , Brown Don R.
Published: February 2021

A new visualization technique is presented that utilizes interactive three-dimensional graphics and perceptual cues to visualize unstructured, sequential data. Upon evaluation the optimum values, trends and relationships between segments and sequences are quickly seen using the perceptual abilities of the human visual system.

This research is applied to visualizing logistics information, were decisions are made based upon multivariate, and sequential information. Using this technique the user can analyze route parameters visually rather than computationally to aid in the decision making process.

The visualization is accomplished through a custom software system written in Java utilizing the Java3D API to generate the three-dimensional visualization.
XYZ-Stage for Scanning Probe Microscope by Using Parallel Mechanism
Authors: Yamakawa Koshiro , Furutani Katsushi , Mohri Naotake
Published: February 2021

This paper deals with a xyz-stage for a scanning probe microscope (SPM) by using a parallel mechanism with 6 degrees of freedom Multilayer piezos are used to change the link length in the prototype. The movable range of the prototype is 100μm in the x- and y- directions and 10μm in the z- directions. The resonant frequency of the prototype is approximately 100 Hz in the x- and y- direction and approximately 50 Hz in the z- direction. The motion of the stage is controlled by the induced charge feedback control to allow compact SPM designs. The motion error is 16 nm in the z- direction by the induced charge feedback control. The displacement of the prototype can be controlled by the induced charge feedback control as well as by the displacement feedback control. This stage is applied to a positioning device of an atomic force microscope (AFM). The grooves of the diffraction grating are observed with good linearity with the AFM. The prototype can be used for the positioning device of the AFM.
Adaptive Motion and Force Control of Robots Performing a Complete Task
Authors: Pagilla Prabhakar R. , Yu Biao
Published: February 2021

In this work, we consider adaptive motion and force control of a robot performing a complete task. By a complete task we mean that the robot desired task contains both free motion and constrained motion. Further, we also consider transition from free motion to constrained motion. We divide the motion of the robot into three phases: (i) inactive phase, where the robot is in free motion, (ii) transition phase, where the transition from free motion to constrained motion takes place, and (iii) active phase, where the robot is in constrained motion with simultaneous force and position control. Uncertainty of the constraint results in the impact of robot with the constraint surface when transition from free motion to constrained motion. We design stable control laws for the three phases that results in an efficient algorithm for robots performing a complete task. Extensive experiments are conducted to show the validity of the proposed control designs.
Synchronization of Two Common-Base-Coupled Nonlinear Rotating-Eccentric-Driven Shakers
Authors: Senator Martin
Published: February 2021

The synchronization, or lock-in, of two coupled, similarly sized rotating-eccentric-driven shakers is studied. The shakers are coupled only by being mounted on a common base, which is suspended on springs and dampers and constrained to translate along a line. This setup models a simplified conceptual version of a no-synchronizing-gearing counter-rotating-eccentric-driven telephone-cable-burying vibrating plow. An approximate quantitative theory of the synchronization of the rotors of these coupled nonlinear autonomous systems is developed in a form that is simple to understand and numerically evaluate. This analysis allows predicting, with good accuracy, whether or not the rotors will synchronize, and if so, to also predict transient and steady state properties of the locked-in motion.
An Experimental Evaluation of Smart Damping Materials for Reducing Structural Noise and Vibrations
Authors: Ahmadian Mehdi , Jeric Kristina M. , Inman Daniel J.
Published: February 2021

An experimental evaluation of the benefits of smart damping materials in reducing structural noise and vibration is presented. The construction of a special test rig for measuring both vibrations and structure-borne noise is discussed. Next, the application of smart damping materials, specifically piezoceramics with electrical shunts, in reducing the vibrations of a test plate is discussed. It is shown that the smart damping materials are able to effectively reduce the vibration peaks at multiple frequencies, with minimal amount of added weight to the structure, as compared to passive viscoelastic damping materials. Further, the test results show that the structure-borne noise at the vibration peaks is substantially reduced with the smart damping materials. The results indicate the viability of smart damping materials for many industrial applications where reducing noise and vibrations is desired with minimal amounts of added weight, or at frequencies below the effective range of passive damping materials.