bluuebunny/crossref_metadata_2025 huggingface dataset:
Implant failure and associated risk indicators: A retrospective study
Authors: Takamoli Joan , Pascual Andres , Martinez‐Amargant Josep , Garcia‐Mur Berta , Nart Jose , Valles Cristina
Published: February 2021

Objectives

To evaluate early and late implant loss rates in a sample of patients who had received implant therapy in a university setting as well as patient‐ and implant‐related variables for implant failure.

Material and methods

This is a retrospective analysis in a cohort of patients who were treated with implant‐supported restorative therapy during the period 2001–2012. Patients were randomly selected from an electronic database and scheduled for an appointment to record subject and implant characteristics. The primary study outcome was implant loss (i.e., early and late implant failure).

Results

A total of 190 patients and 710 implants were included. The mean time in function was 8.2 (SD2.4) years. Four implants (0.6%) failed in four patients (2.1%) prior to connection of the restoration within a mean period of 1.5 (SD1.3) months after surgical procedure. Moreover, 17 subjects (8.9%) exhibited late implant failure, representing 26 implants (3.7%), after a mean follow‐up of 5 years (SD2.2) from prosthesis connection. The final multivariable model indicated three factors related to late implant failure: subjects <55 years (OR = 3.62; 95% CI 1.46–10.22;p = .002), smokers/former smokers (OR = 6.25; 95% CI 1.70–17.52;p = .005), and implants with no access to interproximal hygiene (OR = 7.25; 95% CI 2.20–28.25;p < .001).

Conclusions

The rate for early and late implant failure in a sample of 190 patients who had received implant therapy in a university setting was 2.1% and 8.9%, respectively, at subject level. Subjects <55 years and smokers/former smokers as well as implants with inadequate access to interproximal hygiene were significantly associated with late implant failure.
An illicit artisanal fishery for North Pacific white sharks indicates frequent occurrence and high mortality in the Gulf of California
Authors: Madigan Daniel J. , Arnoldi Natalie S. , Hussey Nigel E. , Carlisle Aaron B.
Published: February 2021

Large sharks shape ecosystems across their geographic ranges and have become a top research and conservation priority. Eastern North Pacific (ENP) white shark (Carcharodon carcharias) aggregations off the United States and Mexico are well described, but their population status is currently uncertain. Population assessments of ENP white sharks are complicated by migrations across international boundaries, vulnerability at aggregation sites, and undetermined mortality levels. While protective legislation exists both in the United States and Mexico, ongoing incidental and unreported catch may undermine assessments and management. Here, access to a clandestine artisanal fishery provides evidence for white shark abundance and mortality in the Gulf of California that has been underestimated by other methods (e.g., satellite telemetry, [by]catch data). Shark size estimates based on tooth measurements suggest abundance of both juvenile and mature sharks in the region, and updated population models indicate the potential for substantial impacts of this fishery on ENP population viability. The data here, fisher‐provided information, and anecdotal evidence suggest potentially high abundance at two specific regions, making directed future research efforts feasible in the Gulf. These data demonstrate that cryptic life histories and geopolitical boundaries can still limit fundamental understanding of megafauna distribution, necessitating international cooperation for both research and management.
One Door Opens: Another Door Shuts?
Authors: Faciolince María , Green Duncan
Published: February 2021

This article explores some of the consequences of open access (OA) for scholars in the global South, centring on what constitutes their equal participation in the global circuit of knowledge production. Building on critical reflections by contributors to the ‘Power Shifts’ project within the From Poverty to Power blog, the limitations of the OA model are shown to be tied to a series of structural features characteristic of the twin systems of academic research and publishing. What the challenges faced by many scholars in the global South demonstrate is that ‘openness’, or inclusion in this format, is not yet the guarantee for equality that many had hoped. The article frames this as a systemic knowledge issue at a global scale that cannot be remedied by a simple reform to academic publishing. The article points to some creative efforts by scholars to forge alternative models for scholarly communication that move away from a marketized and restrictive model of knowledge production, and towards epistemic justice. The authors conclude that while OA represents a positive step forward in making knowledge a public good, it is no substitute for a more comprehensive rethink to pluralize our ways of knowing.
Dynamic left ventricular outflow tract obstruction in a patient with acute coronary syndrome and without the apical akinesia: Potential alternative mechanisms causing a dynamic left ventricular outflow tract obstruction other than a compensatory basal hyperkinesis
Authors: Fujiwara Momo , Kawai Keisuke , Kanazawa Natsuki , Noguchi Masamitsu , Hasokawa Minoru , Nanahoshi Masakazu , Kobayashi Seiichi
Published: February 2021

The mechanism for dynamic left ventricular outflow tract obstruction (LVOTO) after acute coronary syndromes (ACS) is thought to be apical infarction with compensatory hyperkinesia of the residual normally perfused basal segments of the myocardium. However, herein, we report a patient with ACS and dynamic LVOTO (peak gradient of 250 mm Hg at rest) that could not be secondary to apical akinesia. We propose a potential alternative mechanism leading to dynamic LVOTO in ACS, namely, the interplay between sigmoid septum, basal hyperkinesis, and outflow tract narrowing induced by afterload reduction due to acute myocardial ischemia itself.
Percutaneous puncture of an aorto‐bifemoral bypass graft and successful closure with MANTA® device in transfemoral TAVR
Authors: Geyer Martin , Tamm Alexander R. , Oberhoffer Martin , Kreidel Felix , El Beyrouti Hazem , Münzel Thomas , von Bardeleben Ralph Stephan
Published: February 2021

Transfemoral aortic valve replacement (TAVR) has become a standard therapeutic option for patients with symptomatic severe aortic stenosis. Special anatomies can pose distinct challenges for vascular access and later closure of the access site, for example, in preoperated patients. Here, we elucidate a case of transfemoral TAVR with vascular access by direct puncture of an aorto‐bifemoral bypass graft and illustrate the feasibility of vascular closure by an anchored collagen‐plug vascular closure device (Teleflex MANTA®).
Oxidative stress, inflammation, blood rheology, and microcirculation in adults with sickle cell disease: Effects of hydroxyurea treatment and impact of sickle cell syndrome
Authors: Connes Philippe , Möckesch Berenike , Tudor Ngo Sock Emilienne , Hardy‐Dessources Marie‐Dominique , Reminy Karen , Skinner Sarah , Billaud Marie , Nader Elie , Tressieres Benoit , Etienne‐Julan Maryse , Guillot Nicolas , Lemonne Nathalie , Hue Olivier , Romana Marc , Antoine‐Jonville Sophie
Published: February 2021

Inflammation and oxidative stress play a key role in the pathophysiology of sickle cell disease (SCD). However, the potential influence of different sickle genotypes, or hydroxyurea (HU) treatment, on these factors remains poorly documented. The present study compared several plasma markers of inflammation and oxidative stress, as well as microvascular function, between patients with sickle SC disease (HbSC, n = 19) and patients with sickle cell anemia (HbSS) under hydroxyurea (HU) treatment (n = 16), or not (n = 13). Hemorheological parameters and levels of inflammatory (IL‐6, IL‐8, IFN‐γ, MCP‐1, MIP‐1β, TNF‐α) and oxidative stress (AOPP, MDA, MPO) markers were determined. Peripheral microcirculatory cutaneous blood flow and immediate microvascular response to local heat were evaluated using laser Doppler flowmetry. Oxidative stress and inflammation were lower in HbSC patients and HbSS patients under HU therapy compared to HbSS patients not treated with HU. Blood viscosity was higher in HbSC than in HbSS patients treated with or not with HU. Vasodilation response of the cutaneous microcirculation to heat stress was higher in HbSS patients receiving HU treatment. Our results clearly established that both sickle cell genotype and HU treatment modulate inflammation and oxidative stress.
Characteristics and control of the 24‐hour ambulatory blood pressure in patients with metabolic syndrome
Authors: Huang Jian‐Feng , Li Yan , Shin Jinho , Chia Yook‐Chin , Sukonthasarn Apichard , Turana Yuda , Chen Chen‐Huan , Cheng Hao‐Min , Ann Soenarta Arieska , Tay Jam Chin , Wang Tzung‐Dau , Kario Kazuomi , Wang Ji‐Guang ,   the HOPE Asia Network
Published: February 2021

Asian countries are facing an increasing prevalence of metabolic syndrome (MetS), which may aggravate the burden of cardiovascular diseases in this region. MetS is closely associated with ambulatory blood pressure (BP). Patients with MetS, compared to those without, had a twofold higher risk of new‐onset office, home, or ambulatory hypertension. Furthermore, the risk of new‐onset MetS in patients with white‐coat, masked and sustained hypertension was also doubled compared to normotensives. High‐risk masked hypertension and blunted nighttime BP dipping are common in patients with MetS, suggesting perfect 24‐hour BP control with long‐acting antihypertensive drugs and early initiation of combination therapy might be especially important for patients with MetS.
Identification of viral particles in the apoplast of Nicotianabenthamiana leaves infected by potato virus X
Authors: Hu Shuzhen , Yin Yueyan , Chen Buyang , Lin Qi , Tian Yanzhen , Song Xijiao , Peng Jiejun , Zheng Hongying , Rao Shaofei , Wu Guanwei , Mo Xiaohan , Yan Fei , Chen Jianping , Lu Yuwen
Published: February 2021

The apoplast is the extracellular space for signalling, nutrient transport, and plant–microbe interactions, but little is known about how plant viruses use the foliar apoplast. Proteomic analysis of the apoplasts isolated from potato virus X (PVX)‐infected Nicotiana benthamiana plants showed that the coat protein (CP) is the dominant viral component. The presence of the CP in the apoplast was confirmed by western blot, viral nucleic acid was detected by reverse transcription‐PCR and northern blot, and viral particles were observed by transmission electron microscopy (TEM). The apoplast from infected leaves was infectious if rubbed onto healthy leaves but not when infiltrated into them. The exosomes were separated from the apoplast fluid by high‐speed centrifugation and TEM showed that PVX particles were not associated with the exosomes. These results suggest that PVX virions are released to the N. benthamiana apoplast in a one‐way manner and do not share the bidirectional transport of exosomes.
Evolving the structure: climatic and developmental constraints on the evolution of plant architecture. A case study in Euphorbia
Authors: Anest Artémis , Charles‐Dominique Tristan , Maurin Olivier , Millan Mathieu , Edelin Claude , Tomlinson Kyle W.
Published: February 2021

Plant architecture strongly influences ecological performance, yet its role in plant evolution has not been explored in depth. By testing both phylogenetic and environmental signals, it is possible to separate architectural traits into four categories: development constraints (phylogenetic signal only); convergences (environmental dependency only); key confluences to the environmental driver (both); unknown (neither).

We analysed the evolutionary history of the genus Euphorbia, a model clade with both high architectural diversity and a wide environmental range. We conducted comparative analyses of 193 Euphorbia species world‐wide using 73 architectural traits, a dated phylogeny, and climate data.

We identified 14 architectural types in Euphorbia based on trait combinations. We found 22 traits and three types representing convergences under climate groups, 21 traits and four types showing phylogenetic signal but no relation to climate, and 16 traits and five types with both climate and phylogenetic signals.

Major drivers of architectural trait evolution likely include water stress in deserts (selected for succulence, continuous branching), frost disturbance in temperate systems (selected for simple, prostrate, short‐lived shoots) and light competition (selected for arborescence). Simple architectures allowed resilience to disturbance, and frequent transitions into new forms. Complex architectures with functional specialisation developed under stable climates but have low evolvability.
Functional packaging of seeds
Authors: Huss Jessica C. , Gierlinger Notburga
Published: February 2021

The encapsulation of seeds in hard coats and fruit walls (pericarp layers) fulfils protective and dispersal functions in many plant families. In angiosperms, packaging structures possess a remarkable range of different morphologies and functionalities, as illustrated by thermo and hygro‐responsive seed pods and appendages, as well as mechanically strong and water‐impermeable shells. Key to these different functionalities are characteristic structural arrangements and chemical modifications of the underlying sclerenchymatous tissues. Although many ecological aspects of hard seed encapsulation have been well documented, a detailed understanding of the relationship between tissue structure and function only recently started to emerge, especially in the context of environmentally driven fruit opening and seed dispersal (responsive encapsulations) and the outstanding durability of some seed coats and indehiscent fruits (static encapsulations). In this review, we focus on the tissue properties of these two systems, with particular consideration of water interactions, mechanical resistance, and force generation. Common principles, as well as unique adaptations, are discussed in different plant species. Understanding how plants integrate a broad range of functions and properties for seed protection during storage and dispersal plays a central role for seed conservation, population dynamics, and plant‐based material developments.
Perianesthetic neurological adverse events in children: A review of the Wake‐Up Safe Database
Authors: Raghavan Kavitha C. , Hache Manon , Bulsara Purva , Lu Zhaohua , Rossi Michael G.
Published: February 2021

Background

Perianesthetic neurological adverse events are rare in children and have been studied in detail in the settings of cardiac surgery and regional anesthesia. Our study aims to characterize perianesthetic neurological adverse events in children in the setting of all types of surgery and diagnostic or interventional procedures, to evaluate anesthesia's role, and to identify factors amenable to prevention.

Methods

We conducted a retrospective study by reviewing all the anesthetic encounters reported in the Wake‐Up Safe database between January 2010 and December 2017.

Results

The rate of perianesthetic neurological adverse events was 0.49 per 10 000 pediatric anesthetic encounters. The odds of NAE were significantly higher in children who were older than 6 months; had American Society of Anesthesiologists physical status (ASA PS) of 3, 4, or 5; or had American Society of Anesthesiologists Emergency (ASA E) status. Seizures were the most common NAE. Overall, 23 (18.1%) children with neurological adverse events died, and 33 (26%) experienced permanent or severe permanent harm. The risk of death was higher in infants and in children with ASA PS of 3, 4, or 5; ASA E status; preexisting neurological abnormality; or preexisting neurological deficit and in events associated with cardiac arrest or trauma. Anesthesia contributed to 24 (18.9%) events; patient disease was the primary causative factor in 95 (74.8%) adverse events, and 37 (29.1%) events were preventable, including 2 deaths. Preventable factors broadly included inadequate preoptimization, complications during airway management and central venous catheter placement, and suboptimal patient positioning.

Conclusion

Perianesthetic neurological adverse events are rare in children and have a poor outcome. Our study has described pediatric perianesthetic neurological injury in detail and identified contributing factors that can be optimized during various phases of perianesthetic care. This information can be utilized during the informed consent process and to enhance the quality of care in children receiving anesthesia.
Deciphering the genetic basis of wheat seminal root anatomy uncovers ancestral axial conductance alleles
Authors: Hendel Elisha , Bacher Harel , Oksenberg Adi , Walia Harkamal , Schwartz Nimrod , Peleg Zvi
Published: February 2021

Root axial conductance, which describes the ability of water to move through the xylem, contributes to the rate of water uptake from the soil throughout the whole plant lifecycle. Under the rainfed wheat agro‐system, grain‐filling is typically occurring during declining water availability (i.e., terminal drought). Therefore, preserving soil water moisture during grain filling could serve as a key adaptive trait. We hypothesized that lower wheat root axial conductance can promote higher yields under terminal drought. A segregating population derived from a cross between durum wheat and its direct progenitor wild emmer wheat was used to underpin the genetic basis of seminal root architectural and functional traits. We detected 75 QTL associated with seminal roots morphological, anatomical and physiological traits, with several hotspots harbouring co‐localized QTL. We further validated the axial conductance and central metaxylem QTL using wild introgression lines. Field‐based characterization of genotypes with contrasting axial conductance suggested the contribution of low axial conductance as a mechanism for water conservation during grain filling and consequent increase in grain size and yield. Our findings underscore the potential of harnessing wild alleles to reshape the wheat root system architecture and associated hydraulic properties for greater adaptability under changing climate.
Family-oriented interventions in long-term care residential settings: a scoping review protocol
Authors: Eltaybani Sameh , Yasaka Taisuke , Fukui Chie , Inagaki Asa , Takaoka Manami , Suzuki Haruno , Maruyama Miyuki , Yamamoto-Mitani Noriko
Published: February 2021

Objectives:

The objective of this review will be to identify the characteristics (eg, type, duration, and provider) of family-oriented interventions in long-term care residential settings. The authors will also identify which outcomes are reported in the literature when implementing family-oriented interventions.

Introduction:

An array of family-oriented interventions in long-term care residential settings exist. Given the heterogeneity of current literature, mapping characteristics and intended outcomes of family-oriented interventions is an essential step to inform how best to support families of patients in long-term care residential settings.

Inclusion criteria:

This review will consider studies describing family-oriented interventions for families of elderly patients in long-term care residential settings, with no exclusion based on country, gender, or comorbidities. Interventions that address any family-related issue, such as quality of life, psychological burden, and family involvement in patient care, are eligible for inclusion. Studies will be excluded if the patients are cared for at their own homes or institutionalized care is provided on a temporary basis. Quantitative, qualitative, and mixed method study designs will be considered for inclusion.

Methods:

A scoping review will be conducted using the JBI methodological approach. Seven databases will be systematically searched: MEDLINE, CINAHL, Scopus, Evidence-Based Medicine Reviews including Cochrane Library, PsycINFO, OpenGrey, and the Grey Literature Report. Citations will be screened against the inclusion criteria by two reviewers independently. Relevant data will be extracted from the included studies, and will be synthesized, summarized, and reported following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. Findings will be published in a peer-reviewed journal.
La organización social del cuidado de niños niñas y adolescentes en Colombia
Authors: Agudelo Bedoya María Eugenia , Betancourt Maldonado Lady Johanna , Charry Higueras Maritza , Durán Rivera Julia Isabel , Escobar Serrano María Cénide , Estrada Jaramillo Lina , Giraldo Henao Carolina , Gómez Santa Gloria , Gutiérrez Bonilla Martha Lucía , Hernández Bello Amparo , Hernández Quirama Andrea , Jordán Mosquera Carolina , Maldonado Gómez María Cristina , Micolta León Amparo , Morad Haydar María del Pilar , Moreno Roldán Margarita , Giammaría de Osorio Gloria , Perneth Pareja Leidy , Puyana Villamizar Yolanda , Rodríguez López Mercedes , Rojas Betancur Héctor Mauricio , Salas Rodas Julián , Zapata Posada Johanna Jazmín
Published: February 2021

No somos nada sin el otro/a. Esta es la mejor expresión del valor fundamental del cuidado. El cuidado que sostiene la vida. El cuidado que durante esta dolorosa pandemia ha sido la base fundamental para proteger la vida en todas sus expresiones. El cuidado que por siglos ha sido invisibilizado y desplegado especialmente por millones de mujeres en el mundo. Quien cuida y a quienes se cuida ha puesto en evidencia la división tajante sobre los cuidados. Como lo señala Judith Butler, todas y todos nacemos dependientes. En eso estamos en condición de igualdad. Pero es en la división sexual del trabajo y en la valoración que las sociedades hacen del cuidado donde empiezan las diferencias y las profundas desigualdades. Este libro nos ofrece un bien común intelectual, al documentar de forma cooperativa la organización social del cuidado de niñas, niños y adolescentes en Bogotá, Cartagena, Medellín, Cali y Bucaramanga, y nos propone como proyecto de sociedad “un movimiento significativo que ponga en el centro la vida y el cuidado como acciones para construirla, promoverla y conservarla”. Angela María Robledo Gómez En medio de la pandemia, no puede ser más oportuno que este excelente trabajo publicado por la Editorial Pontificia Universidad Javeriana vea la luz. Luego de varios años de investigación, elaboración y discusión, las profesoras Yolanda Puyana Villamizar, Amparo Hernández Bello y Martha Lucía Gutiérrez Bonilla entregan a la sociedad colombiana un riguroso estudio sobre cómo se da, en cinco ciudades colombianas, la organización social del cuidado de niños, niñas y adolescentes. Sus resultados han sido discutidos, validados y mejorados en diversos escenarios académicos con participación de investigadores de América Latina. Ello implica que sus resultados no son producto de una moda ni de la situación, sino que ayudan a problematizarla. Gracias al juicioso ejercicio comparativo, dan luces sobre qué se está haciendo para el cuidado de niños, niñas y adolescentes en las ciudades colombianas. Claramente, facilitan el análisis y la reflexión sobre los impactos de la circunstancia que, como sociedad, afrontamos. Además, nos ayudan a sugerir, indicar y propiciar mejores decisiones. Andrés Dávila Ladrón de Guevara
Investigar a la intemperie: reflexiones sobre métodos desde las ciencias sociales en el oficio
Authors: Flórez Flórez María Juliana , Leal Fagúndez Jorge Daniel , López Jiménez Carlos Arturo , Márquez Restrepo Martha Lucía , Esguerra Muelle Camila , Ojeda-Ojeda Diana Carolina , Olarte-Olarte María Carolina , Castillo Rojas Natalia , Sánchez Parra Tatiana , Sañudo Pazos María Fernanda
Published: February 2021

El ejercicio contemporáneo de la investigación en las diferentes ciencias sociales implica pensar constantemente en los procesos metodológicos, su naturaleza, la supremacía del problema de investigación sobre los límites disciplinares y la incidencia de su trabajo en el presente, esto es, su política. Estos cuatro planos conforman un volumen que se ajusta, a su vez, en función de las fuentes, las preguntas de investigación, sus objetivos, la situación de quien investiga… Así, pensar el método involucra una combinatoria permanente de elementos que desborda los aspectos procedimentales y, por tanto, una falta de resguardo metodológico, disciplinar y ontológico, pues ni siquiera las comunidades con que dialogamos o las fuentes con que trabajamos nos garantizan de antemano su forma o su estabilidad a largo plazo. Esta triple falta de garantía nos pone a la intemperie, ante el devenir de un trabajo que nunca promete resultados definitivos, o al menos duraderos, pero que sí hace apuestas políticas, como ocurre con los ocho capítulos que reúne Investigar a la intemperie, producidos por investigadoras del Instituto de Estudios Sociales y Culturales Pensar. Estos trabajos presentan reflexiones de métodos tomadas del oficio cotidiano de investigación en ámbitos como la migración, las políticas públicas, la producción de espacialidades, de saberes formales y no formales, de cuerpos definidos por las especificidades locales del conflicto armando colombiano, y desde perspectivas críticas como los estudios feministas, decoloniales, culturales y de las migraciones.
The Behavior of a Brittle Material at Failure
Authors: Frocht Max M.
Published: February 2021

This paper reports a number of unusual and instructive fractures and shows that the strength of bakelite, which may be considered a typical brittle material, is determined by the maximum tensile stresses as computed by advanced methods of stress analysis. The material used in the tests here described was obtained from the Bakelite Corporation of America and is known by the numbers BT-61-893 and BT-46-001.
The Calculation of Dampers for Systems Subject to Self-Induced Vibration
Authors: Baker J. G. , Mikina S. J.
Published: February 2021

The authors point out that complete elimination of self-induced vibration cannot be treated generally because the systems in which it occurs, and the conditions under which the systems are subject to this type of vibration, are so varied. However, such vibration can be reduced by damping, and the means employed can be discussed in terms applicable to the whole class of self-induced vibrations. The authors show that the time-displacement curve for the building up of a self-induced vibration is a convenient basis for calculating the amount of damping required to prevent the vibration from building up.
Working Stresses for Members Subjected to Fluctuating Loads
Authors: Marin Joseph
Published: February 2021

Many machine members, such as shafts and axles, are subjected to stresses which do not remain constant in magnitude but fluctuate with time. Under such conditions, the resisting strength of the material is reduced and hence a different working stress from that for static stresses must be used. To determine this working stress, it is convenient to first establish the maximum working stress for simple tension in the case of fluctuating stress. With this as a basis, the case of combined stresses can then be considered. The evaluation of working stresses for members subjected to fluctuating combined stress has been made by Soderberg, based on a shear theory of failure. However, recent tests by Gough, indicate that for ductile materials, a shear-energy theory is in better agreement with experiment. The following paper deals primarily with the formulation of such a theory and its application to design. In addition, a comparison is made of designs by this theory with those now in use. In this discussion, ductile materials are considered and, in particular, medium-carbon steels.
End Reactions and Stresses in Three-Dimensional Pipe Lines
Authors: Karelitz G. B. , Marchant J. H.
Published: February 2021

The authors present a method for the numerical computation of the end forces and couples in a three-dimensional pipe line. The method takes care of a pipe line with any number of straight parts connected by bends. A procedure of computation is also shown when parts of the pipe line are skewed. The ends of the line may be partially or completely constrained against rotation and translation. A construction for the analysis of stresses in the pipe bends is given. The method is illustrated by a sample computation of the end forces and couples in a steam main which is restrained against thermal expansion.
The Behavior of Rectangular Plates Under Concentrated Load
Authors: Sturm R. G. , Moore R. L.
Published: February 2021

This paper presents a summary of the experimental and analytical research on flat plates under concentrated normal loads conducted at the Aluminum Research Laboratories. The experimental work includes tests on a number of different sizes of plates, ranging from 1/8 in. to 1 in. thickness, loaded on spans of from 48 to 384 times the thickness. The effect of the degree of load concentration, types of edge support, and position of the load upon the stresses and deflections have been the principal variables studied. Cases of bending alone, and combined bending and direct stress have been considered. The analytical work refers to the existing general analysis of the flat-plate problem, from which formulas suitable for design purposes have been derived.
Recent Developments of the Theory of Turbulence
Authors: Dryden Hugh L.
Published: February 2021

A brief account is given of the principal concepts which have been utilized in the formulation of theories of the turbulent motion of fluids prior to 1935 and the new approach originated by G. I. Taylor in that year.

A bibliography of 31 papers is included.
The Crank Arrangement of a Nine-Cylinder Engine
Authors: Lewis F. M. , Breault E. E. , Donaldson R. M.
Published: February 2021

The authors discuss the multiplicity of possible crank arrangements for a nine-cylinder engine and devise a means by which certain crank arrangements can be chosen which will meet certain arbitrary requirements of reciprocating and rotating moments. The investigation has been limited to crank arrangements with 40-deg crank intervals.
Vibration Stress Measurements in Strong Centrifugal Fields
Authors: Kearns Charles M. , Guerke Ralph M.
Published: February 2021

Following a brief review of existing methods of measuring vibrational stresses in strong centrifugal fields, the authors discuss the characteristics of carbon-resistance strain gages and indicate their method of use.

These gages may be calibrated statically and used for dynamic measurements with an accuracy of plus or minus ten per cent; and with present cementing technique they can be applied in fields up to 12000 × gravity.

The necessary instruments for use with these pickups are described and several records of aircraft-propeller tip stresses are shown.
Distortion of the Photoelastic Fringe Pattern in an Optically Unbalanced Polariscope
Authors: Mindlin Raymond D.
Published: February 2021

This paper describes the results of an investigation of the effect of inaccuracies in the two quarter-wave plates of a photoelastic polariscope on the configuration of the monochromatic fringe pattern. It is shown that the fringe pattern is distorted to an extent which depends upon the orientations of the axes of principal stress and the difference between the retardations of the two plates.
A Rapid Method for the Determination of Principal Stresses Across Sections of Symmetry From Photoelastic Data
Authors: Frocht M. M.
Published: February 2021

The author discusses: (a) Mesnager’s theorem of isoclinics, (b) the characteristic curve of tangential stresses across a section of symmetry, (c) a formula for the maximum tangential stresses for the case of a central circular hole between fields of pure tension, (d) the slope of the p curve at a point corresponding to a cupic point, (e) recent improvement in the determination of free boundary stresses, and (f) formulas for the position of cupic points for two cases. A new method for the determination of the principal stresses across sections of symmetry from photoelastic data is illustrated with three examples: (1) Bars in tension or compression with central circular holes, (2) grooved beams in bending, and (3) rings or disks with circular central holes subjected to two concentrated diametral loads.
The Fundamentals of Three-Dimensional Photoelasticity
Authors: Hetényi M.
Published: February 2021

The method of three-dimensional photoelasticity is based on the experimental fact that samples of phenolic resins, such as Bakelite, Marblette, and Trolon, when annealed in a loaded condition show a complete preservation of (a) the elastic deformation and (b) the accompanying birefringence produced by the loading at the annealing temperature. After presenting a historical review of the method, the author discusses the current theory of the molecular structure of phenolic resins by which the phenomena observed in the annealing procedure can be explained. Test results are given which prove the elasticity of Bakelite at elevated temperatures. Applications of the method are also discussed.
Feature Validation in a Multiple-View Modeling System
Authors: Dohmen Maurice , de Kraker Klaas Jan , Bronsvoort Willem F.
Published: February 2021

A new approach to specification and maintenance of feature validity conditions in a multiple-view feature modeling system is presented. Each view of a product contains a feature model. Features are specified declaratively in an object-oriented language, using constraints to specify feature validity conditions. Constraints are also used to specify relations between features. Validation of the feature models is done by a constraint manager that integrates different solving techniques. The constraint graph is mapped by the constraint manager onto constraints that are handled by dedicated solvers. If views are consistent, i.e. their feature models represent the same geometry, feature parameters can be changed. Changes are propagated through link constraints between different views.
Neural-Taguchi Method for Robust Design
Authors: Wang Gou-Jen , Tsai Jhy-Cherng , Tzeng Pai-Chung , Chen Tsorng-Chi
Published: February 2021

Neural-Taguchi, a new engineering analysis method that combines the neural-network and the Taguchi techniques for better improvement of engineering design is proposed in this paper. Explicit system model that allows precise prediction and easy optimizing is constructed in terms of a multilayer feedforward neural network. Advantages and good performances of the proposed Neural-Taguchi method are well illustrated by a die cast component analysis problem.
Survey on Use of Virtual Environments in Design and Manufacturing
Authors: Gupta Rakesh
Published: February 2021

This paper surveys the work being done in Virtual Environments (VE) in both design and manufacturing with an emphasis on the industrial use of Virtual Environments. Research and applications are categorized into seven major areas: prototyping and design visualization; verification of design assembly; design creation; concurrent product design and marketing; manufacturing; training and maintenance; and human factors in design. These seven categories are neither mutually exclusive nor collectively exhaustive. For each of these major areas, the paper discusses the issues and the state of the art, emphasizing recent significant advances.
An Integrated Approach to Teaching Mechanism Analysis Using Working Model
Authors: Buffinton Keith W. , Chang Victor W.
Published: February 2021

An approach to engineering education that integrates traditional analytical techniques, modern computational software, and physical hardware has been developed at Bucknell University. This paper describes the implementation of this approach in a juniorlevel required course in mechanism analysis. The content of the course supplements textbook material with computational and experimental laboratory exercises. The computational components of the laboratories are based primarily on the use of the software package Working Model and, to a lesser extent, Pro/JR. Three particular laboratories are described in detail in the paper. The laboratories seek to develop and reinforce the view that textbook analysis techniques and sophisticated computer software are merely tools and only useful if applied intelligently. Moreover, the laboratories emphasize the need for validation and verification in engineering design and analysis. The integrated interactive environment provided in the laboratories not only allows students to quickly see the limits of analytical and computational techniques but also to gain a firsthand understanding of the performance of actual mechanisms.
Rapid Prototyping of Fuzzy Logic Controllers
Authors: Gorman Kevin J. , Rahnamai Kourosh J.
Published: February 2021

The rapid prototyping of fuzzy logic controllers is accomplished by using the tools Matlab, Simulink, Fuzzy Logic Toolkit, and Real-Time Workshop. Device drivers were developed for Simulink for interfacing with DT2801 and DT2821 data acquisition boards. The fuzzy logic inference engine for the Fuzzy Logic Toolkit was modified to allow the systems to work as independent programs and to be downloadable to DSP (Digital Signal Processing) boards. Simulink is used to graphically implement fuzzy logic controllers. The Real-Time Workshop is used to compile blocks from Simulink into C code, then into an independent executable program, both on the PC and a dSpace DSP (Digital Signal Processing) board. Graphical interfaces are created and debugged by using dSPACE’s tools, Cockpit and Trace. By combining these tools, real-time fuzzy logic controllers are developed in laboratory environments.
Impact Analysis of a Dropped Object Using Static Finite Element Software
Authors: Spencer Todd J. , Suchora Daniel H.
Published: February 2021

The purpose of this study was to develop a method to solve impact problems using a static finite element analysis software package. This allows an engineer to approximate the stresses in a body when it is dropped and strikes the ground or supports. This is intended mainly for use when an advanced finite element package that solves dynamic problems is not available.

The method developed in this work was used to predict stresses and strains in a simply supported test beam. The test beam was dropped in the laboratory and experimental strains were recorded. The results of these two methods were then compared, which indicates the validity of this work. This method can be easily applied to more complicated structures.
An Eighteen-Node Solid Element for Thin Plate/Shell Analysis
Authors: Sze K. Y.
Published: February 2021

In this paper, hybrid stress method is employed to formulate stabilization vectors for the uniformly reduced integrated eighteen-node solid elements. The assumed stress is contravariant in nature and is devised based on the strain associated with the commutable zero energy modes of a geometrically regular element. It will be seen that the stabilization vectors can be derived and programmed explicitly without resorting to numerical integration loops. Admissible matrix formulation is employed in evaluating the flexibility matrix and the resulting matrix is diagonal in nature.
Generalization of Classical Modal Analysis
Authors: Ma F. , Lee W. C.
Published: February 2021

The coefficients of a linear nonconservative structure are arbitrary matrices lacking the usual properties of symmetry and definiteness. Classical modal analysis is extended in this paper so as to apply to structures with nonsymmetric coefficients. The extension utilizes equivalence transformations and does not require conversion of the equations of motion to first-order forms. Compared with the state-space approach, the generalized modal analysis can offer substantial reduction in computational effort and ample physical insight.
Application of Two-Step Component Mode Synthesis for System Eigensolutions
Authors: Ramani Anand , Knight Charles E.
Published: February 2021

Component Mode Synthesis (CMS) is a dynamic substructuring technique for approximate eigensolutions of large degree-of-freedom systems divisible into two or more components. System synthesis using component modes results in approximate eigenparameters. The approximation is improved by using more component modes in synthesis. Typically, all component modes up to x times the frequency range of interest are required to assure reasonable accuracy, where x varies from 2 to 10. This paper demonstrates the two-step CMS approach, wherein, the first step involves system synthesis using the minimum number of component modes (x∼1) required to obtain approximate eigenvalues up to a preselected frequency and the second step uses additional component modes in a convergence scheme operating on the system eigenparameters calculated in the first step. Results of studies on spring-mass systems, beam and plate models, and a refrigeration compressor assembly show that the two-step method provides the analyst some insight into the convergence and accuracy of the eigenparameters without resolving the system over and over with more component modes. The method is also efficient in terms of solution time, when compared to conventional CMS using the Jacobi method and the subspace-iteration method.
Geometry Reconstruction of Vectorized Drawings Consisting of Orthographic Views
Authors: Das Atish K. , Langrana Noshir A.
Published: February 2021

The benefits of the existing CAD systems are not available to a large number of engineering drawings which were created on paper using conventional drafting methods. There is a need for an automated system which will convert the scanned images of these drawings into a format recognizable by a CAD system. One of the main components of such a system is the vectorization (raster-to-vector) system which converts the binary image of the scanned drawing into a set of straight line segments, arcs, and circles. The accuracy of the vectorized output in terms of the location and size of the various entities is very important if it is to be used for further processing. This paper describes a system which rectifies errors in the vectorized output using a constraint-based approach based on the principles of variational geometry. The system considers drawings consisting of three orthographic views. The dimension sets present in the drawing and the logical relationship existing between the views are recognized and interpreted to obtain a set constraints governing the geometry of the object. The set of constraint equations are then numerically solved to obtain the exact coordinates of the points used to describe the geometry.
Two-Stage Algorithm for Rapid Determination of the Bending Sequence in Sheet Metal Products
Authors: Radin B. , Shpitalni M. , Hartman I.
Published: February 2021

This paper presents an algorithm for solving the complex and critical problem of bending sequence in sheet metal manufacturing. Finding the bending sequence and required tool assignment presents a large combinatorial problem which is impossible to solve optimally for practical applications within a reasonable period of time.

The paper presents a two-stage algorithm. The first stage finds a feasible solution based upon collision avoidance heuristics. The second stage rapidly seeks an alternative feasible sequence with a lower cost without exceeding time limitations. The algorithm is very practical because it reaches a low-cost solution quickly within computer memory limitations.

In this paper, the problem is defined, the approach is presented formally, and finally, the power of the algorithm is demonstrated by solving bending sequences for real products.
A New Approach to CE by Multifunctional Mapping Process
Authors: Wang Qingwen , Zhou Ji , Xiao Renbin , Yu Jun
Published: February 2021

This paper takes Concurrent Engineering (CE) and Multifunctional Designs (MFD) as mapping and inverse mapping process between every agent’s functional space and physical space. The mapping and inverse mapping algorithms are introduced and an example of shaft design is given to test the algorithms. Based on the new approach, some problems of CE such as negotiation and design tasks management can be dealt with more easily due to inverse mapping process.
Simulation of Multibody Dynamics in Autocad
Authors: Lin Shih-Tin , Lin Jhy-Hong
Published: February 2021

A general purpose multibody dynamics algorithm is written and merged into AutoCAD. This merger creates a user friendly environment for the simulation of multibody mechanical systems such as robot manipulators. Users can prepare input data of the dynamic code easily after creating an AutoCAD drawing of the multibody system. After the dynamic analysis is complete, the results can be easily used to produce animation slides in AutoCAD. The multibody dynamics algorithm uses a recursive variational formulation. This formulation has been proven to be computationally more efficient.
Integration of Knowledge-Base and CAD System for the Machinery Layout Design of Ships
Authors: Lee J. K. , Lee K. H. , Park N. S. , Jang Y. U. , Bae J. Y. , Shim H. S.
Published: February 2021

The current trend of CAD system is to make the system intelligent. CAD systems need to be intelligent in the sense that they must be able to use knowledge to achieve the designer’s goal. In the early stages of ship design, more experienced and higher level knowledge is required rather than that of detail design. The existing CAD systems have several limitations in terms of satisfying the requirements of real design. Accordingly, a more powerful and capable CAD system is required to support the activities in the early stage of design. Recently the application of expert systems has been considered as a tool for extending the capability of existing CAD systems. In this paper, we present an approach to implement a practical knowledge-based system for the machinery layout design of a ship engine room. The knowledge-base is implemented and verified in the actual CAD environment of a ship engine room, named MADES, which we develop in this study. The approaches presented in this paper provide a practical example of a knowledge-based system for complex design problems, and can also provide guidance on implementing an integrated design expert system that extends the capability of existing CAD systems.
Optimal Rough Cutting Tool Path on Cross Sections of Sculptured Surface
Authors: Lee Hi K. , Yang Gyun E. , Ryuh Beom S. , Park Se H.
Published: February 2021

The optimal tool path for NC milling of a sculptured surface is given on cross sections of the surface, which extends the application of contour tool path from 2 dimensional milling to 3-axis and 5-axis milling. The cutting speed in rough cutting is the main objective of the optimal path. The contour tool path on cross sections of the surface can generate the rough cutting path in high speed without excessive cutting force, chatter and heavy wear of the cutting tool. Also, the path can be expanded to 3 -axis and 5-axis milling for machining of complicated surfaces.
Heuristic Modification of Cutting Conditions Using Neural Network
Authors: Park Byoung T. , Park Myon W.
Published: February 2021

Process planners usually need to make modifications to recommended cutting conditions obtained from machining data handbooks in order to satisfy requirements for individual operation. However, because these modifications are based on the experience of process planners, the systematization of this procedure requires experience-oriented methods. In this paper, a new procedure and technology that allows the implementation of an intelligent system for the milling process is proposed. A Mill-COPS based on such a proposal has been developed. Neural network methodology is introduced to identify mathematical models for optimizing the cutting conditions in this system. The results are demonstrated with respect to given cutting conditions.