bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of α2‐adrenergic agonists combined with anesthetics and their implication in pulmonary intravascular macrophages‐insulted pulmonary edema and hypoxemia in ruminants
Authors: Abouelfetouh Mahmoud M. , Salah Eman , Ding Mingxing , Ding Yi
Published: March 2021

Alpha2‐adrenergic agonists have been implicated in the development of pulmonary edema (PE) and sustained hypoxemia that lead to life‐threatening pulmonary distress in ruminants, especially with sensitive and compromised animals. Recently, there is limited understanding of exact mechanism underlying pulmonary alterations associated with α2‐adrenergic agonist administration. Ruminants have a rich population of pulmonary intravascular macrophages (PIMs) in the pulmonary circulation, which may be involved in the development of pulmonary alveolo‐capillary barrier damage. Hence, the central thesis of this review is overviewing the literatures regarding the systemic use of α2‐adrenergic agonists in domestic ruminants, focusing on their pulmonary side effects, especially on the influence of PIMs on the lung. At this moment, further studies are needed to provide a clear emphasis and better understanding of the potential role of PIMs in the lung pathophysiology associated with α2‐adrenergic agonists. These preliminary studies would be potentially to develop future medications and intervention targets that may be helpful to alleviate or prevent the critical striking pulmonary effects, and thereby improving the safety of α2‐agonist application in ruminants.
Like a Grinding Stone: How Crowdfunding Platforms Create, Perpetuate, and Value Health Inequities
Authors: Kenworthy Nora
Published: March 2021

This article explores how inequities are reproduced by, and valued within, the increasingly ubiquitous world of medical crowdfunding. As patients use platforms like GoFundMe to solicit donations for health care, success stories inundate social media. But most crowdfunders experience steep odds and marginal benefits. Drawing on the problematic figure of the “black box” in health disparities research and technology studies, I offer ethnography as a tool for unpacking often inscrutable and complex pathways through which online platforms amplify inequities. By leveraging both online and traditional research strategies—a platform analysis and paired narratives of crowdfunders’ disparate experiences, drawn from open‐ended interviews—this article explores how inequities are created and experienced by users. The analysis highlights how inequities are simultaneously central to the functioning of this marketplace and occluded by its platform design. Consequently, crowdfunding is concealing health inequities while shifting public values about who is entitled to health care, and why.
Lighting the way: Forces driving the diversification of bioluminescent signalling in sea fireflies
Authors: DeLeo Danielle M. , Bracken‐Grissom Heather D.
Published: March 2021

Understanding the drivers of diversification and processes that maintain biodiversity remains a central theme of evolutionary biology. However, these efforts are often impeded due to disparities across species and environments and the genetic complexity underlying many traits. The factors driving biodiversity can be more readily understood by focusing on the genetics of diversification, of one or few genes shared across species, with large influence over an organism's phenotype (Templeton, 1981; Wright, 1984). In this pursuit, previous studies often focus on the selective pressures that impact phenotypic diversity (Brawand et al., 2014; Yokoyama et al., 2015), often overlooking the contribution of neutral processes (i.e., genetic drift). In this issue of Molecular Ecology, Hensley et al. (2020) use an integrative approach, including RNA sequencing, in vitro protein expression and spectral measurements, to explore the drivers behind the diversification of bioluminescent signalling in cypridinid ostracods (Figure 1). Typical bioluminescent reactions primarily include an enzyme (luciferase) and substrate (luciferin). By focusing on a single gene, this study traces the molecular evolution of (c)luciferase in sea fireflies, elucidating diverse signatures of selection, drift and constraint to decipher the link between genotype and phenotype of their bioluminescent emissions.
Genetic diversity and population structure in Vitis species illustrate phylogeographic patterns in eastern North America
Authors: Péros Jean‐Pierre , Cousins Peter , Launay Amandine , Cubry Philippe , Walker Andy , Prado Emilce , Peressotti Elisa , Wiedemann‐Merdinoglu Sabine , Laucou Valérie , Merdinoglu Didier , This Patrice , Boursiquot Jean‐Michel , Doligez Agnès
Published: March 2021

Geographical distribution and diversity of current plant species have been strongly shaped by climatic oscillations during the Quaternary. Analysing the resulting divergence among species and differentiation within species is crucial to understand the evolution of taxa like the Vitis genus, which provides very useful genetic resources for grapevine improvement and might reveal original recolonization patterns due to growth habit and dispersal mode. Here, we studied the genetic structure in natural populations of three species from eastern North America: Vitis aestivalis, V. cinerea and V. riparia using different marker types. Vitis aestivalis and V. cinerea showed higher diversity than V. riparia. The two former species are less differentiated, confirming an earlier divergence of V. riparia. V. aestivalis and V. riparia exhibited different genetic groups on both sides of the Appalachian Mountains that could mirror different recolonization routes from southern refugia. Genetic structure was stronger in V. cinerea, for which two varieties (var. berlandieri and var. cinerea) are morphologically recognized. Our results confirm this distinction and suggest the existence of three other lineages within var. cinerea. These discontinuities appear linked to adaptation of var. berlandieri to dry and limy areas of Texas and partially to the Mississippi River Valley. Rapid range expansions from refugia upon climate warming are also suggested by the low linkage disequilibrium values observed. Furthermore, large variation for downy mildew resistance was observed in the three species. Our findings appeared consistent with the vegetation history of eastern North America.
Impacts of plant invasions in native plant–pollinator networks
Authors: Parra‐Tabla Víctor , Arceo‐Gómez Gerardo
Published: March 2021

The disruption of mutualisms by invasive species has consequences for biodiversity loss and ecosystem function. Although invasive plant effects on the pollination of individual native species has been the subject of much study, their impacts on entire plant–pollinator communities are less understood. Community‐level studies on plant invasion have mainly focused on two fronts: understanding the mechanisms that mediate their integration; and their effects on plant–pollinator network structure. Here we briefly review current knowledge and propose a more unified framework for evaluating invasive species integration and their effects on plant–pollinator communities. We further outline gaps in our understanding and propose ways to advance knowledge in this field. Specifically, modeling approaches have so far yielded important predictions regarding the outcome and drivers of invasive species effects on plant communities. However, experimental studies that test these predictions in the field are lacking. We further emphasize the need to understand the link between invasive plant effects on pollination network structure and their consequences for native plant population dynamics (population growth). Integrating demographic studies with those on pollination networks is thus key in order to achieve a more predictive understanding of pollinator‐mediated effects of invasive species on the persistence of native plant biodiversity.
Self‐reported awareness during general anesthesia in pediatric patients: A study from Wake Up Safe
Authors: Lee Angela C. , Redding Amanda Townsend , Tjia Imelda , Rana Md. Sohel , Heitmiller Eugenie
Published: March 2021

Background

Awareness under general anesthesia occurs rarely, but can result in emotional trauma. Although well‐studied in adults, there is a paucity of data on unintentional awareness in children.

Aims

This case series examines instances of self‐reported awareness registered with Wake Up Safe, a patient safety organization that maintains a database of adverse events in pediatric anesthesia.

Methods

Cases of self‐reported intraoperative awareness submitted to Wake Up Safe from January 1, 2010 to May 31, 2020 were reviewed for circumstances, causative factors, and level of harm.

Results

Fourteen cases of self‐reported intraoperative awareness out of 555 360 cases in patients aged 5–20 years were noted during the study period. Overall incidence of awareness was 2.52 (95% CI: 1.38–4.23) cases per 100 000 patients, or approximately 1:40 000. Self‐reported intraoperative awareness was more frequently associated with cardiac and gastrointestinal endoscopic procedures. Incidence for cardiac procedures was 20.34 (95% CI: 8.18–41.90) cases per 100 000 patients. Incidence for gastrointestinal endoscopic procedures was 7.74 (95% CI: 1.60–22.62) cases per 100 000 patients. Most patients were assessed to have suffered harm.

Conclusions

Self‐reported intraoperative awareness is a rare complication in pediatric patients that has implications for harm. Compared to awareness cases elicited by a questionnaire method, cases of self‐reported awareness during general anesthesia may represent those that have a greater impact. A preoperative discussion of intraoperative awareness should be considered for procedures that carry a higher likelihood of awareness in order to mitigate harm.
Videoendoscopic evaluation of swallowing using normal saline in NICU infants
Authors: Mizogami Masae , Hasegawa Hisaya , Yamada Yosuke , Kitamura Rei , Wasa Masanori
Published: March 2021

Background

Videoendoscopic evaluation (VE) of swallowing involves inserting a small flexible endoscope transnasally to allow direct observation of pharyngeal and laryngeal structures and swallowing functions. In our neonatal intensive care unit (NICU) VE is performed in infants suspected of severe swallowing dysfunction, using normal saline (NS) with the aim of minimizing the detrimental effect of aspiration on respiration caused by VE. This retrospective study was conducted to evaluate the usefulness of VE using NS in NICU infants.

Methods

We enrolled 28 infants who demonstrated clinical signs of swallowing dysfunction or who were ready to start oral feeding. Swallowing evaluations were completed using flexible fiberoptic laryngobronchoscopy (FLB). While observing the pharyngeal and laryngeal cavity with FLB, NS was gradually increased by 1 mL and injected up to a maximum of 3 mL, and the swallowing reflex, tracheal aspiration, and pharyngeal residue were observed.

Results

Median gestational age was 37 weeks 6 days, median birthweight 2,539 g, and median age at first examination was 107.5 days. Abnormalities in VE were observed in 20 cases, most of which were upper airway lesions. Most of these upper airway abnormalities were pharyngeal lesions. In two pharyngeal lesion cases, swallowing function improved using positive airway pressure.

Conclusions

Infants with pharyngeal lesions demonstrated abnormal VE findings. Furthermore, positive airway pressure improved swallowing in some cases, suggesting that narrowing of the pharyngeal cavity may affect swallowing function. In addition, results suggest that VE using NS is a safe and useful method for evaluating swallowing function and determining countermeasures in NICU infants.
Reflecting on one's best possible self as a leader: Implications for professional employees at work
Authors: Jennings Remy E. , Lanaj Klodiana , Koopman Joel , McNamara Gerry
Published: March 2021

Most professional employees aspire to leadership, and this suggests that a best possible leader self—a personalized representation of who an employee aspires to be at their best as a leader in the future—is likely a relevant and motivating self‐representation for employees at work. Integrating theory on best possible selves with control theory, we suggest that activating a best possible leader self can have beneficial effects for the way that any employee feels and behaves at work. Specifically, we propose that employees who reflect on their best possible leader self will enact more leader‐congruent behaviors and subsequently perceive themselves as more leaderlike due to the positive affect generated by such reflection. We found support for our theoretical expectations in an experimental experience sampling study that included both current and aspiring leaders. On days when employees reflected on their best possible leader self, they engaged in more helping and visioning via positive affect. Furthermore, employees perceived themselves as more leaderlike after performing these leader‐congruent behaviors, as captured by higher enacted leader identity and clout. We discuss theoretical and practical implications for research on leadership.
Subthreshold error corrections predict adaptive post‐error compensations
Authors: Beatty Paul J. , Buzzell George A. , Roberts Daniel M. , Voloshyna Yelyzaveta , McDonald Craig G.
Published: March 2021

Relatively little is known about the relation between subthreshold error corrections and post‐error behavioral compensations. The present study utilized lateralized beta power, which has been shown to index response preparation, to examine subthreshold error corrections in a task known to produce response conflict, the Simon task. We found that even when an overt correction is not made, greater activation of the corrective response, indexed by beta suppression ipsilateral to the initial responding hand, predicted post‐error speeding, and enhanced post‐error accuracy at the single‐trial level. This provides support for the notion that response conflict associated with errors can be adaptive, and suggests that subthreshold corrections should be taken into account to fully understand error‐monitoring processes. Furthermore, we expand on previous findings that demonstrate that post‐error slowing and post‐error accuracy can be dissociated, as well as findings that suggest that frontal midline theta oscillations and the error‐related negativity (ERN) are dissociable neurocognitive processes.
Virulence mechanisms of vibrios belonging to the Splendidus clade as aquaculture pathogens, from case studies and genome data
Authors: Zhang Weiwei , Li Chenghua
Published: March 2021

The Vibrio genus belonging to the Splendidus clade includes 16 described species and can infect a broad host range of cultured animals in marine environments, resulting in various diseases and high mortality, thus leading to high economic losses in aquaculture. Here, we provide a brief description of the virulence of Splendidus clade pathogens and the known or potential virulence factors as well as the virulence regulation factors provided by both case studies and genome data. Splendidus clade pathogens possess virulence factors, including adhesins, extracellular proteases, haemolysins and siderophores, to adhere to, invade and combat hosts. Global regulators, such as the quorum sensing system and σ factors, are involved in virulence regulation. Chemotaxis, flagellum, secretion and toxin‐antitoxin systems, as well as small RNAs that are frequently involved in virulence, are also included in the discussion of the genome data of Splendidus clade pathogen. A better understanding of the pathogenesis, virulence factors and virulence regulation will not only illustrate the means used by Splendidus clade pathogens to infect their hosts but also offer new targets for the development of control strategies against Splendidus clade pathogen infection in aquaculture.
Comparative Energy Regionalism: North America and the European Energy Community
Authors: Herman Lior , Ariel Jonathan
Published: March 2021

Although literature on energy cooperation highlights that cooperation is more successful at the regional level, it largely fails to understand and conceptualize energy cooperation as part of the wider phenomenon of regionalism. Energy cooperation tends to be analyzed through prisms of security and geopolitics, thus, downplaying other important regional integration processes. The present paper addresses this lacuna, defining energy regionalism and conceptualizing its various dimensions, logics, motivations, and interests. We apply a comparative perspective, examining two regions which exhibit extensive energy cooperation yet differ in several ways: North America and the European Energy Community. Our findings suggest various trajectories and models, and indicate that formal institutionalization is neither a necessary condition for nor a guarantee of strong energy regionalism. We discern that regional anchor is key in North American and European energy regionalism.
Platelet transfusion refractoriness and anti‐HLA immunization
Authors: Blandin Lucie , Dougé Aurore , Fayard Amandine , Bay Jacques‐Olivier , Berlie Guillaume , Pereira Bruno , Lemal Richard , Rouzaire Paul
Published: March 2021

Platelet transfusion refractoriness (PTR), defined as an unsatisfactory post‐transfusion platelet count increment, is a common complication of patients receiving multiple transfusions. Different strategies are described in the management of PTR. In this work, we demonstrate the efficacy of the detection and identification of anti‐HLA antibodies in the recipient using a threshold of 3000 mean fluorescence intensity (MFI), and the seek of donors not expressing HLA antigens against which the patient is immunized.
Decellularized xenografts in regenerative medicine: From processing to clinical application
Authors: Capella‐Monsonís Héctor , Zeugolis Dimitrios I.
Published: March 2021

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.
Large Displacements With Small Strains in Loaded Structures
Authors: Swainger K. H.
Published: March 2021

This paper considers the case of flexible structures in which displacements can be large although strains are small. The theory gives an “exact” solution in a large class of problems where the displacements are large but predictable closely from the physical conditions imposed. In this method, the major part of the displacement is “guessed,” and then a further “small” displacement calculated from equations, which are developed, to assure compatibility. As a simple but not trivial example, the generation of an elastic cylinder from a flat plate is considered to illustrate the method.
A Mechanical Analyzer for the Solution of Vibration Problems of a Single Degree of Freedom
Authors: Weibel E. E. , Cokyucel N. M. , Blau R. E.
Published: March 2021

A mechanical-analogy-type analyzer is described which is of relatively simple construction being limited to single-degree-of-freedom problems. Whithin this limitation solutions may be obtained for systems which include various types of nonlinear elasticity and of nonlinear damping. Included is a generalized solution obtained on the analyzer giving in dimensionless form the maximum displacements and forces in a system having nonlinear (linear plus cubic) elasticity and linear damping caused by a force pulse of constant magnitude and finite duration. The bearing of the results on the starting torques in nonlinear systems is indicated.
Aerodynamic Oscillations in Suspension Bridges
Authors: Pinney Edmund
Published: March 2021

Following the failure in 1940 of the Tacoma Narrows suspension bridge by wind-driven oscillations, the need for developing in advance adequate data concerning wind speeds at which such oscillations occur became apparent. Numerous studies and experiments were undertaken on the subject, the present paper dealing with a symmetrical suspension bridge having two towers in which both sidespan and tower effects are considered. A modification is given to include the effects of roadbed “slats,” and a method is outlined for obtaining flutter speeds from roadbed section models which may fit into standard wind tunnels. The theory is applied to the Tacoma Narrows Bridge.
Discussion of the Forces Acting in Tension Impact Tests of Materials
Authors: Clark D. S. , Duwez P. E.
Published: March 2021

A method of measuring the forces acting on a specimen during a tension impact test is described briefly in this paper. In this method a dynamometer is used in tests made in a rotary impact testing machine in which impact velocities up to approximately 200 fps can be attained. The method of computing force-time relations prevailing in a specimen subjected to tension impact is described from the standpoint of the theory of the propagation of elastic and plastic strain. The method is applied to a specific material to illustrate the computing procedure. A theoretical stress-time diagram has been computed for a specimen of SAE 1020 cold-rolled steel 0.300 in. diam and 8 in. long for an impact velocity of 150 fps. This computation has been made (a) on the basis that the dynamometer is rigid, and (b) on the basis of a dynamometer mounted in a manner approximately equivalent to that in the actual equipment. The diagrams are for the stress-time relations at the fixed end of the specimen. The computed curves are compared with an experimental force-time diagram obtained on the same material. The general shape of the experimental diagram is quite similar to the theoretical diagram computed on the basis of a nonrigid dynamometer.
The Influence of the Dimensional Factors on the Mode of Yielding and Fracture in Medium-Carbon Steel—I: The Geometry and Size of the Flat Tensile Bar
Authors: Miklowitz Julius
Published: March 2021

A detailed study of the local principal strains, during uniform straining in a flat tension bar, has proved valuable in explaining the observed large variations of the local necking strains, with uniform changes in geometry and size of the bar. An analogy has been brought out between the restraining action of the bar heads on the gage material, and that of the stagnant material of the neck on the flowing material adjacent to it. In both cases the magnitude of the restraining dimension is important, the degree of restraint increasing with an increase in dimension. The study in deformation is presented for both uniform straining and the complicated crosslike neck at fracture. The maximum strains in the neck increased when the bar size decreased. The maximum strain, in the lateral direction parallel to the bar width, became less, as the width-to-thickness ratio of the bar increased from 1 to 7. Beyond this value, no effects were noted. The axial strain, calculated from the two lateral strains, reflected their trends.
Plastic Deformation of a Circular Diaphragm Under Pressure
Authors: Gleyzal A.
Published: March 2021

In this report a numerical solution is given of a set of equations consisting essentially of three plasticity laws, two strain-displacement laws, and two equilibrium laws which describe the action of a clamped, thin, circular diaphragm as it yields plastically when pressure is applied to one side. The stresses, strains, thickness variation, and deflections for any thin circular diaphragm of a given material may be computed by the numerical integration of the equilibrium conditions, the geometric conditions relating displacements and strains, and the stress-strain laws. The solution may be reduced to the solution of a second-order differential equation with the radial distance r as independent variable. The solution depends upon an experimentally determined function, τ (γ), which describes the stress-strain properties of the material, and upon three parameters, the pressure p, the original thickness h0, and the radius a of the clamping ring. It is found that for a given material, a family of curves with pa/h0 as a parameter serves to predict the solution for any thin circular diaphragm of the same material. This analysis has been carried out for a particular function τ(γ) based upon results of a tensile test made on a specimen of medium steel. Graphs of theoretically and experimentally determined values of deflection, radial and circumferential strains, radial and circumferential stresses, and thickness corresponding to various pressures are presented which apply to all diaphragms made of the same steel as this specimen.
Contact Stresses in the Rolling of Metals—1
Authors: MacGregor C. W. , Palme R. B.
Published: March 2021

Special equipment is described which was designed and constructed to investigate the distributions of the normal pressures and the longitudinal and transverse shearing stresses along the arc of contact during the rolling of metals between plain cylindrical rolls. While the paper is restricted to a description of this apparatus, it is planned to utilize it in studying the effects of many of the important rolling variables both on the contact stresses and on the resulting mechanical properties of the rolled product. Experimental results will be presented in a later paper.
Flow of a Compressible Fluid Through a Series of Identical Orifices
Authors: Robinson C. S. L.
Published: March 2021

This paper contains a method for computing the weight flow of a gas or vapor through a number of like orifices. It is based upon the general equation for a single orifice and upon certain reasonable assumptions. There are included curves showing the influence of the number of orifices. For expansions beyond the over-all critical-pressure ratio, the effect of each additional orifice is increasingly reduced. For example, increasing the number of like orifices from 6 to 7 will decrease the flow only about 5 per cent. Two applications of this study are suggested, i.e., to multiple-orifice devices for heat-exchange equipment, and to labyrinth packing for shaft seals.
Long-Term Performance Assessment of Swell Packers Under Different Oilfield Conditions
Authors: Qamar Sayyad Zahid , Pervez Tasneem , Akhtar Maaz , Kharusi Moosa Al
Published: March 2021

Swelling elastomer seals and packers provide effective zonal isolation in difficult oil and gas fields, resulting in significant savings in rig time and development expenses. Companies involved in petroleum engineering applications provide no information about the longevity or endurance of swelling elastomer packers when exposed to different conditions in the well. This paper describes the design and construction of a test facility for long-term performance assessment of actual full-scale water and oil-swell packers, and the results of the 5-year study. The ten packers are made of three types of swelling elastomers, are kept in crude oil and saline solutions at room and high temperatures, and are exposed to varying high pressures. Regular logs of readings were maintained over the whole study period. Earlier sealing was observed in elastomers immersed in low-salinity water and subjected to high temperature. Rate of swelling was higher in water-based elastomers than in oil-based seals. One packer never sealed completely. Pressurized tubes either retained sealing the whole time or re-sealed after removing of pressure or reducing it to a lower value. Results for the fast-swell and medium-swell elastomer, low- and high-salinity water and crude oil, and low- and high-operating temperatures were mostly in line with short-term tests on laboratory samples published earlier. This unique longevity assessment study can be used by drilling engineers and developers in assessing the suitability of swelling elastomers for target fields and in improving the design of swell packers.
Applying a Theta-Krill Herd Algorithm to Energy Management of a Microgrid Considering Renewable Energies and Varying Weather Conditions
Authors: Aldosary Abdallah , Rawa Muhyaddin , Ali Ziad M. , Abusorrah Abdullah , Rezvani Alireza , Suzuki Kengo
Published: March 2021

Recently, researchers have shown an increased interest in using renewable-based distributed generations (DGs) in microgrids (MGs). Therefore, the economic operation of MGs plays a vital role in reducing total daily costs and greenhouse gas emissions in the modern power system. This study presents a day-ahead optimization management for a grid-tied MG supplied by small-scale renewable energy sources (RESs) like photovoltaic (PV) systems. The major aim of the suggested optimal energy management system is to minimize the cost of RERs and storage facilities in the MG for power generation while satisfying technical constraints. In addition, an improved mathematical model is suggested for the PV power generation using real data for four dissimilar days. To attain accurate results, uncertainties in the generations, load demand, and market price are probabilistically modeled. To handle the optimization problem, the θ-modified krill herd (θ-MKH) algorithm is used. The suggested algorithm for solving the optimization problem is investigated on numerical examples with different RESs and storages in the MG and compared with conventional approaches. The results attained illustrate that the recommended algorithm can utilize the cheapest sources while covering technical constraints.
An Automated Machine Learning-Genetic Algorithm Framework With Active Learning for Design Optimization
Authors: Owoyele Opeoluwa , Pal Pinaki , Vidal Torreira Alvaro
Published: March 2021

The use of machine learning (ML)-based surrogate models is a promising technique to significantly accelerate simulation-driven design optimization of internal combustion (IC) engines, due to the high computational cost of running computational fluid dynamics (CFD) simulations. However, training the ML models requires hyperparameter selection, which is often done using trial-and-error and domain expertise. Another challenge is that the data required to train these models are often unknown a priori. In this work, we present an automated hyperparameter selection technique coupled with an active learning approach to address these challenges. The technique presented in this study involves the use of a Bayesian approach to optimize the hyperparameters of the base learners that make up a super learner model. In addition to performing hyperparameter optimization (HPO), an active learning approach is employed, where the process of data generation using simulations, ML training, and surrogate optimization is performed repeatedly to refine the solution in the vicinity of the predicted optimum. The proposed approach is applied to the optimization of a compression ignition engine with control parameters relating to fuel injection, in-cylinder flow, and thermodynamic conditions. It is demonstrated that by automatically selecting the best values of the hyperparameters, a 1.6% improvement in merit value is obtained, compared to an improvement of 1.0% with default hyperparameters. Overall, the framework introduced in this study reduces the need for technical expertise in training ML models for optimization while also reducing the number of simulations needed for performing surrogate-based design optimization.
One-Step Synthesis of O-Self-Doped Honeycomb-Like Hierarchically Porous Carbons for Supercapacitors
Authors: Lin Shiying , Mo Lanlan , Wang Feijun
Published: March 2021

A facile and environmentally friendly approach to produce self-doped hierarchically porous carbon as electrode material for high-performance supercapacitor was demonstrated. Three-dimensional honeycomb-like hierarchically porous carbon was successfully obtained by one-step carbonization and activation of sodium carboxymethyl cellulose (CMC) via K2CO3. With the optimized temperature of carbonization and activation, the porous carbon material achieved well-shaped hierarchically pores (micro-, meso-, and macropores) like a honeycomb, ultrahigh specific surface area (1666 m2 g−1), as well as highly O-self-doping (3.6 at%), endowing an excellent electrochemical properties for the electrode in a three-electrode system. The porous carbon electrode material delivered a high specific capacitance of 300.8 F g−1 at 1 A g−1, an eminent rate capability of 228.4 F g−1 at the current density up to 20 A g−1 and outstanding cycle stability of 94.3% retention after 10,000 cycles. Therefore, the CMC-derived hierarchical porous carbon activated by K2CO3 would have promising foreground in the application of supercapacitors.
Ultrasonic Structural Health Monitoring Approach to Predict Delamination in a Laminated Beam Using d15 Piezoelectric Sensors
Authors: Altammar Hussain , Salowitz Nathan
Published: March 2021

Ultrasonic structural health monitoring (SHM), employing embedded piezoelectric elements to actuate and sense ultrasonic waves, has greatly advanced in recent years. This paper presents a novel approach to address the prevailing challenges in the inspection of laminated structures for delamination using shear-mode (d15) piezoelectric transducers, composed of lead zirconate titanate (PZT). To experimentally evaluate the effectiveness of the proposed approach, a beam-like laminated specimen consisting of internally embedded d15 square PZTs was fabricated with simulated delamination at the interface of an adhesive joint. The evaluation of the results showed that the location of shear-mode actuators is a critical factor to detect delamination and to predict the propagation path of delamination. Delamination initiated close to actuators is more likely to be detected owing to their remarkable sensitivity of structural stiffness surrounding their region. The antisymmetric A0 wave mode generated by these actuators exhibits high interaction with damage, suggesting internally embedded d15 PZTs are a viable approach that can potentially advance the inspection tools of ultrasonic SHM.
Domain-Oriented Semantics for Feature Modeling Based on TAE Structures Using Conditional Attributed Rewriting Systems
Authors: Otto Harald E. , Kimura Fumihiko , Mandorli Ferruccio , Cugini Umberto
Published: March 2021

Requirements of intelligent CAD systems are aimed to enable them to support the designer throughout his/her entire activity, starting from conceptual design and ending with, according to given specifications, an almost complete design object description.

Current approaches featuring geometrical constraint-based systems with parametric or variational models, allow the designer to consider the realized design object description as an archetype of a family, based on a unique morphological model with unambiguous sets of parameterized rules. However, functionality for both design and reasoning, are limited to the low geometric level, leaving most of related information from the design intend and related technology unconsidered.

Our objective of given study is, to extend the present functionality of existing approaches by integrating different types of knowledge and incorporate dedicated semantics in form features and feature-based methodologies. As a basic representation, typed attributed entity structures (TAE) are used. Computation is performed over domain structured alphabets of attributed symbols using a conditional attributed rewriting system.

An application example in form of a wing rib, taken from aerospace engineering, is used, to verify and demonstrate the modeling and consistent handling of knowledge formations within our developed framework. Current limits of our new approach are discussed and a comparison related to the functionality of existing systems is undertaken, to direct the focus on further enhancements and extensions of our approach.
Feature-Based Modeling of Product Families
Authors: Laakko Timo , Mäntylä Martti
Published: March 2021

A feature-based product modeling system is introduced where the user can incrementally create and modify product families. Product family and feature descriptions are coded in a special definition language and can be easily added and modified by the user. The descriptions include dynamically maintained constraints. The definition language description of a new family can be automatically created on the basis of a recognized prototypical instance. A stored design history can be used for generating the geometry definition of the family.
Recognize Features From Freehand Sketches
Authors: Hwang Teng-Shang , Ullman David G.
Published: March 2021

A feature recognition system which allows the computer to capture sketches made by a mechanical designer is described. The system takes the user’s input sketching actions and interprets the collection of 2D geometric elements to extract 3D information from them in terms of mechanical features. A application domain, knowledge representation, the derivation of feature recognition rules, inference mechanism, and conclusions are presented in this article.
Handling Blending Features in Form Feature Recognition Using Convex Decomposition
Authors: Menon Sreekumar , Kim Yong Se
Published: March 2021

Form features intrinsic to the product shape can be recognized using a convex decomposition called Alternating Sum of Volumes with Partitioning (ASVP). However, the domain of geometric objects to which ASVP decomposition can be applied had been limited to polyhedral solids due to the difficulty of convex hull construction for solids with curved boundary faces. We develop an approach to extend the geometric domain to solids having cylindrical and blending features. Blending surfaces are identified and removed from the boundary representation of the solid, and a polyhedral model of the unblended solid is generated while storing the cylindrical geometric information. From the ASVP decomposition of the polyhedral model, polyhedral form features are recognized. Form feature decomposition of the original solid is then obtained by reattaching the stored blending and cylindrical information to the form feature components of its polyhedral model. In this way, a larger domain of solids can be covered by the feature recognition method using ASVP decomposition. In this paper, handling of blending features in this approach is described.
Design for Injection Molding: Using Process Simulation to Assess Tolerance Feasibility
Authors: Busick David R. , Beiter Kurt A. , Ishii Kos
Published: March 2021

This paper proposes an effective use of process simulation in the dimensional tolerancing of injection molded thermoplastic components. The complexities of the injection molding process make it difficult for designers to assign dimensional tolerances. No standard method exists for predicting the feasibility of a design tolerance. Advances in injection molding simulation software offer information that could aid in tolerancing. However, engineers have not effectively used these programs for tolerancing. This paper proposes a methodology for using process simulation in evaluating the feasibility of a tolerance scheme. The methodology entails using simulation to quantify the dimensional errors due to process variations and estimate sensitivities. Comparison of simulation results with tolerances specified by designers helps them evaluate whether the desired tolerances are feasible. The paper describes the steps required for estimating the dimensional errors and defines criticality as a measure of tolerance feasibility. A plastic housing for an electrical switch serves as an illustrative example.
An Expert Consultation Environment for Creating Customized Knowledge-Based Systems for CAD
Authors: Narayanan Parasuram , Jayaram Sankar
Published: March 2021

Although the field of CAD has come a long way in recent years, the integration of CAD with engineering/mechanical design, especially the integration of CAD with conceptual design, has not been given enough importance. Tools which facilitate the custom development of conceptual CAD software are still not available. This is especially true in the case of intelligent CAD systems. This paper describes the philosophy and design of a framework which will facilitate the creation of knowledge-based expert systems to support conceptual design.

The design of an object-oriented framework which will assist in the creation of customized expert systems for CAD applications is presented. This framework, known as the Expert Consultation Environment, provides the CAD programmer with tools to create the expert system. This framework consists of various object-oriented classes which the programmer would use during the creation of the knowledge-based expert system. A prototype of a portion of the framework was implemented. The use of this prototype framework in the creation of an expert system for a multi-disciplinary design application is discussed. The framework described in this paper would assist the programmers of CAD systems in building expert systems that are tailor-made for conceptual design. Any expert system created using an implementation of this framework will be very flexible, adaptable, and extendible.
A Semantic Framework for Flexible Feature Validity Specification and Assessment
Authors: Bidarra Rafael E. , Teixeira José C.
Published: March 2021

Feature-based modeling is being given an increasing significance in the development of computer-aided design environments, due to its expressive power in capturing various aspects of designer intent. Integrity problems arise, however, when the specification of complex shapes requires several features to overlap or interact. In this paper we address the problem of form feature behavior representation for such situations, developing a semantic model that captures the actual contribution of each feature in the overall model shape. Within this semantic framework it becomes possible to establish naturally and flexibly the desired validity conditions for each feature class, enhancing a modeling system with the ability for permanently monitoring each feature’s conformity with that original specification.
Towards Automated Construction of Molds and Dies
Authors: Rosen David W.
Published: March 2021

Starting with the motivation to provide manufacturing feedback to designers and to reduce bottlenecks in the design-manufacturing transition, algorithms for constructing molds and dies are presented. The concept of “virtual manufacturing” serves as the umbrella for this work. Computational prototypes, rather than hardware prototypes, can greatly speed product development, process design, and process tooling development. The work presented here contributes directly to all three areas, since automated tool construction enables accurate, detailed Design-for-Manufacturing feedback to aid product development, enables process design through simulation, and provides an initial tool design that can be enhanced by a tool fabricator.

A series of algorithms are presented for the automated construction of tools from a purely geometric reasoning viewpoint. Starting with a solid model of a component, undercuts are found and classified, then moving tool sections are constructed. For external undercuts, accessibility directions are found and are used to construct tooling side actions. Automated undercut accessibility determination has not been previously previously reported in the literature. For internal undercuts, form pins are constructed that access the undercut through the core of the tool. Undercut classification is important since their cost implications can be reported back to the component designer during design. Two examples illustrate the application of the algorithms.
Concurrent Engineering for Composites: Requirement Analysis About the Environment
Authors: Zhang Jian , Hahn H. Thomas
Published: March 2021

This paper has first examined the manufacturing process of composites and the feasibility to apply concurrent engineering idea to improve its productivity. Then the key components including their roles played in the manufacturing process of composites and the requirements to the CE system for composites have been properly identified and analysed. Based on these requirements, an infrastructure based system architecture for the CE system was designed. Finally, the scheme to implement a CE system for composites was presented.
Case Prototype Based Design: Philosophy and Implementation
Authors: Mao Quan , Qin Jing , Zhang Xinfang , Zhou Ji
Published: March 2021

In this paper, the philosophy of case prototype based design is proposed. The system architecture of CascDEST which is an embodiment of this philosophy are presented in the paper, also an algorithm of neural network based analogical case retrieval and a strategy of constraint networks based object scheme evaluation and modification are described in details. Finally, an application of CascDEST in three series industrial steam turbine design is presented.
Interpreting Feature Viewpoints for Concurrent Engineering
Authors: Fu Z. , Nee A. Y. C.
Published: March 2021

Concurrent (or simultaneous) engineering has recently been proposed as a potential means to improve the product development practice. It requires the product life-cycle aspects such as manufacturing requirements to be considered during the stages of designing a part so that the design feedback on the manufacturability, assemblability and so on can be provided to the designers. To support this purpose needs the integration of geometric models, analysis and synthesis tools as well as domain knowledge while the design is in progress.

In the past few years, the concept of features has received significant attentions in the context of design and manufacturing automation. However, the application of features is currently limited, mainly due to the domain-dependent nature of features. A crucial problem has been the interpretation of multiple feature viewpoints, particularly, the conversion among feature representations, that is to support the reasoning about feature-based representations of a product design from a specific perspective and their interpretation. In this paper, important engineering perspectives and related feature-based representations supporting concurrent design and manufacturing have been identified. A methodology of interpreting different feature representations has been proposed based on a coupling between grammatical formalism and knowledge-based inference. A case study of applying this methodology to the conversion from design features based representation into representations suitable for machining process planning is reported.
Preliminary Phase in Cell Level Modelling
Authors: Jin J. Q. , Franks I. T. , Loftus M.
Published: March 2021

This paper addresses the need to add a preliminary phase to cell level modelling. It is accepted that the Cell level plays an important role within a CIM structure. To assist implementation and research into cell systems, an appropriate modelling technology is required. However, existing modelling methods are not sufficiently adequate. A consolidated approach towards cell level modelling is desirable. Requirements capture and representation is one of the most critical processes in system modelling. The proposed modelling phase is considered as an enabling mechanism through which improved communication between system modellers and users, and consequently better representation of users requirement, can be achieved. This paper discusses the need for a preliminary phase of cell level modelling, especially at the requirements analysis stage of the system life cycle. The essential constituents of this phase are discussed. A partial method, specially designed for the modelling process in this strategy, is briefly introduced.