bluuebunny/crossref_metadata_2025 huggingface dataset:
Recurrences following treatment of proliferative verrucous leukoplakia: A systematic review and meta‐analysis
Authors: Proaño‐Haro Alex , Bagan Leticia , Bagan Jose V.
Published: March 2021

Background

A systematic review and meta‐analysis were made of the incidence of recurrences in patients with proliferative verrucous leukoplakia (PVL) subjected to different types of treatment.

Methods

The study was carried out following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) statement guidelines. A literature search was made in the Medline (PubMed), EMBASE, and Web of Science databases, together with a manual search, covering the period from 1985 to January 2020, with no language restrictions. Studies were included if they described treatments applied to at least 10 patients with the corresponding outcomes. Methodological quality was evaluated using Jadad scale and Newcastle‐Ottawa tool. Global incidence was calculated by random effects meta‐analysis using the Comprehensive Meta‐analysis version 3.0 software. Publication bias was assessed using funnel plots and the Duval and Tweedie trim and fill method.

Results

Of the 922 identified articles, 12 were found to meet the inclusion criteria. Most of them presented moderate or low risk of bias. A total of 397 patients were analyzed. The mean age was 62.34 years and 248 were women (62.5%). The mean follow‐up was 79.3 months. The most frequent treatment was surgical removal with a cold scalpel or laser (339 patients). A total of 232 subjects presented lesion recurrence. The combination of proportions global effect meta‐analysis yielded a recurrence rate of 67.2% (95% CI: 48.3–81.8), with the absence of publication bias.

Conclusions

There is not enough scientific evidence to conclude that any treatment strategy is able to reduce the recurrence in PVL.
Characterization of the microbiome and immune response in corals with chronicMontiporawhite syndrome
Authors: Brown Tanya , Sonett Dylan , Zaneveld Jesse R. , Padilla‐Gamiño Jacqueline L.
Published: March 2021

Coral diseases have increased in frequency and intensity around the tropics worldwide. However, in many cases, little is known about their etiology.Montiporawhite syndrome (MWS) is a common disease affecting the coralMontipora capitata, a major reef builder in Hawai'i. ChronicMontiporawhite syndrome (cMWS) is a slow‐moving form of the disease that affectsM. capitatathroughout the year. The effects of this chronic disease on coral immunology and microbiology are currently unknown. In this study, we use prophenoloxidase immune assays and 16S rRNA gene amplicon sequencing to characterize the microbiome and immunological response associated with cMWS. Our results show that immunological and microbiological responses are highly localized. Relative to diseased samples, apparently healthy portions of cMWS corals differed in immune activity and in the relative abundance of microbial taxa. Coral tissues with cMWS showed decreased tyrosinase‐type catecholase and tyrosinase‐type cresolase activity and increased laccase‐type activity. Catecholase and cresolase activity were negatively correlated across all tissue types with microbiome richness. The localized effect of cMWS on coral microbiology and immunology is probably an important reason for the slow progression of the disease. This local confinement may facilitate interventions that focus on localized treatments on tissue types. This study provides an important baseline to understand the interplay between the microbiome and immune system and the mechanisms used by corals to manage chronic microbial perturbations associated with white syndrome.
Priming for interprofessional collaboration: Assessment tools as socialisation in disguise
Authors: Price Sheri Lynn
Published: March 2021

Price discusses how priming students to recognize interprofessional collaboration as essential to their professional roles is essential for effective interprofessional education.
A comparison of four different Nutritional Profile models in their scoring of critical nutrient levels in food products targeted at Brazilian children
Authors: Silva Alessandro Rangel Carolino Sales , Braga Luiza Vargas Mascarenhas , Anastácio Lucilene Rezende
Published: March 2021

The implementation of front‐of‐pack labelling to assist consumers in making healthier food choices requires an appropriate Nutritional Profile Model (NPM) to be defined. However, four different models have been proposed in Brazil: the Pan American Health Organization (PAHO), the Brazilian Association of Food Industries (ABIA) and National Health Surveillance Agency (ANVISA) less (1) and more restrictive (2) models. The present study aimed to use the information provided on the labels of eight ultra‐processed food categories selected from the most popular group of foods targeted at Brazilian children, to score critical nutrient levels according to the four different NPMs and compare the proportion of products categorised as ‘high’, ‘medium’ or ‘low’ according to each one. Labels (n = 409) were collected in supermarkets in Belo Horizonte‐MG, Brazil. Data were tabulated, and a comparison of the ‘high’ content of the four nutrients, total sugars, total and saturated fats and sodium, according to the four NPMs, was performed. Agreement between ‘high’, ‘medium’ and ‘low’ scores according to the different NPMs, in comparison with the PAHO model, was performed using the Kappa test. Of all ‘fruit’ drinks, 95% were considered as ‘high’ in total sugars by the PAHO model, while only 5% were categorised as ‘high’ by the ABIA and ANVISA 1 models. For total sugars, no product in the cakes, breakfast cereals and yogurts categories and only 5.7% of the sandwich cookies were categorised as ‘high’ by the ABIA model, while 100% of sandwich cookies were categorised as having a ‘high’ total sugars content by the PAHO and ANVISA models. Similar findings were observed for breakfast cereals, yogurts and corn snacks for the proportion of products scoring ‘high’ for saturated fats and sodium. Kappa's concordance analysis showed moderate to excellent agreement between the PAHO and ANVISA 2 models. It was observed that the PAHO model indicated more foods with a ‘high’ content of critical nutrients. We conclude that the ABIA model is more permissive when compared to the other models and the PAHO model more restrictive.
Changes in renal function and predictors affecting renal outcome of living kidney donors: a nationwide prospective cohort study
Authors: Kim Yunmi , Kim Min Ji , Lee Yu Ho , Lee Jung Pyo , Lee Jeong‐Hoon , Yang Jaeseok , Kim Myoung Soo , Kim Taehee , Kang Sun Woo , Kim Yeong Hoon ,   KOTRY study group
Published: March 2021

Aim

The safety of donors is an important issue in living donor kidney transplantation. We investigated serial changes in renal function and predictors affecting the renal outcome of living kidney donors.

Methods

We obtained the data of 456 kidney donors registered to the Korean Organ Transplantation Registry from 2014 to 2016. The estimated glomerular filtration rate (eGFR) changes according to the development of incident chronic kidney disease (CKD) and factors related to CKD were analysed. CKD was defined as an eGFR <60 ml/min/1.73 m2 or the presence of proteinuria or albuminuria. The change in eGFR over time was analysed using a linear mixed model.

Results

At 2 years after kidney donation, 21.7% of the donors (99/456) developed CKD. Annual eGFR changes after nephrectomy were 2.2 ml/min/1.73 m2/year in donors without CKD, and − 0.4 ml/min/1.73 m2/year in donors with CKD. Higher systolic blood pressure was associated with higher risk of CKD (odds ratio [OR] 1.322 per 10 mmHg increment, 95% confidence interval [CI] 1.036–1.686, p = .025). Higher pre‐donation eGFR (OR 0.906 per 1 ml/min/1.73 m2 increment, 95% CI 0.876–0.936, p < .001) and higher ratio of eGFR at discharge to pre‐donation (OR 0.603 per 0.1 increment, 95% CI 0.426–0.849, p = .004) were related to lower risk of CKD.

Conclusion

Kidney donors without incident CKD at 2 years after donation showed gradual increases in eGFR, whereas donors with CKD had relatively constant eGFR. A low ratio of eGFR at discharge after nephrectomy to baseline was a risk factor of CKD.
Breaks in peristaltic integrity predict abnormal esophageal bolus clearance better than contraction vigor or residual pressure at the esophagogastric junction
Authors: Rogers Benjamin D. , Cisternas Daniel , Rengarajan Arvind , Marin Ingrid , Abrahao Luiz , Hani Albis , Lequizamo Ana M. , Remes‐Troche José M. , Perez de la Serna Julio , Ruiz de Leon Antonio , Zerbib Frank , Serra Jordi , Gyawali C. Prakash
Published: March 2021

Background

High‐resolution impedance manometry (HRIM) evaluates esophageal peristalsis and bolus transit. We used esophageal impedance integral (EII), the ratio between bolus presence before and after an expected peristaltic wave, to evaluate predictors of bolus transit.

Methods

From HRIM studies performed on 61 healthy volunteers (median age 27 years, 48%F), standard metrics were extracted from each of 10 supine water swallows: distal contractile integral (DCI, mmHg cm s), integrated relaxation pressure (IRP, mmHg), and breaks in peristaltic integrity (cm, using 20 mmHg isobaric contour). Pressure and impedance coordinates for each swallow were exported into a dedicated, python‐based program for EII calculation (EII ratio ≥ 0.3 = abnormal bolus clearance). Univariate and multivariate analyses were performed to assess predictors of abnormal bolus clearance.

Key Results

Of 591 swallows, 80.9% were intact, 10.5% were weak, and 8.6% failed. Visual analysis overestimated abnormal bolus clearance compared to EII ratio (p ≤ 0.01). Bolus clearance was complete (median EII ratio 0.0, IQR 0–0.12) in 82.0% of intact swallows in contrast to 53.3% of weak swallows (EII ratio 0.29, IQR 0.0–0.57), and 19.6% of failed swallows (EII ratio 0.5, IQR 0.34–0.73,p < 0.001). EII correlated best with break length (ρ = 0.52,p < 0.001), compared to IRP (ρ: −0.17) or DCI (ρ: −0.42). On ROC analysis, breaks predicted abnormal bolus transit better than DCI or IRP (AUC 0.79 vs. 0.25 vs. 0.44,p ≤ 0.03 for each). On logistic regression, breaks remained independently predictive of abnormal bolus transit (p < 0.001).

Conclusions & Inferences

Breaks in peristaltic integrity predict abnormal bolus clearance better than DCI or IRP in healthy asymptomatic subjects.
Towards a pragmatic view of theories in ecology
Authors: Travassos‐Britto Bruno , Pardini Renata , El‐Hani Charbel N. , Prado Paulo I.
Published: March 2021

Ecology has received many criticisms concerning its theoretical maturity, often on the grounds that it lacks laws and, therefore, a clear and unified theoretical background. We argue that the search for laws to understand ecological theory was prompted by the (perhaps inadvertent) adoption of an axiomatic perspective that traces back to syntactic and some semantic views of theory. We present examples showing how these views have a common logical structure, in which axioms can be interpreted as laws, even though there are semantic views that assume a more flexible perspective on theories. We then present, as an alternative, more pluralistic and process‐based approaches that fall under the umbrella of pragmatic views of theories. Under this view, a theory is an ever‐changing, context‐dependent, collective construct, and thus does not necessarily fit into pre‐defined logical structures such as those adopted by axiomatic views. We show that the diversity of models and structures found in ecological theories, as well as the way knowledge is produced within this field of science, makes ecology an exemplary candidate to be approached from a pragmatic perspective. Based on ecological succession theory as a case study, we illustrate how assuming a pragmatic view allows for new analyses that may foster our understanding of the theoretical structure and consequently further our understanding of ecological phenomena.
Extending the growth rate hypothesis to species development: Can stoichiometric traits help to explain the composition of macroinvertebrate communities?
Authors: Beck Miriam , Mondy Cédric P. , Danger Michael , Billoir Elise , Usseglio‐Polatera Philippe
Published: March 2021

Ecological stoichiometry seeks to understand the ecological consequences of elemental imbalances between consumers and their resources. Therein, the well‐accepted growth rate hypothesis (GRH) states that organisms exhibiting rapid growth have higher phosphorus (P) demand – and thus lower C:P and N:P ratios – than slow growing ones, due to a higher allocation to P‐rich rRNA. However, GRH has rarely been extended to other biological traits than growth, especially at the community level. In this study, we investigated whether macroinvertebrate stoichiometric traits (e.g. C:P and N:P ratios) can be linked to their development traits, and whether these stoichiometric traits are related to macroinvertebrate community assemblage under different nutrient conditions. We allocated more than 400 European taxa to different groups, defined using available information about three development‐related traits: ‘life span', ‘voltinism' and ‘number of reproductive cycles per individual'. We sampled 18 invertebrate taxa in six streams exhibiting different levels of nutrient concentration and measured their stoichiometric traits. Further, we quantified invertebrate taxon abundances in these streams during an annual survey. Based on these data, we tested whether community composition regarding the developmental groups differs, depending on nutrient concentration. We found significant differences in the proportions of the developmental groups along a gradient of water N:P, in relation to their stoichiometric traits. Taxa with low C:P and N:P ratios were generally associated with faster development groups, and these taxa tended to occur at higher proportions in streams exhibiting low dissolved N:P ratios. In contrast, communities from P‐poor, high dissolved N:P streams, were dominated by slowly developing taxa with high N:P ratios. Our results highlight that extending the GRH to species development rate might give some insights about the mechanisms by which nutrient concentrations in ecosystems influence consumers' community composition.
Extraction of a very old His bundle pacing lead: A safe and effective procedure?
Authors: Migliore Federico , Dall'Aglio Pietro , Falzone Pasquale Valerio , Bertaglia Emanuele , Zanon Francesco
Published: March 2021

Permanent His bundle pacing (HBP) has rapidly been adapted into clinical practice in recent years as a physiologic pacing. The 3830 (Medtronic Inc, MN, USA) pacing lead commonly used for HBP is lumenless, and there are limited reports available on extraction of this lead. No data exists on transvenous lead extraction (TLE) of very old HBP lead. Concerns remain about injury to the conduction system during extraction and the lack of lumen for placing a locking stylet for TLE when powered sheaths are required. We reported a unique case of TLE of very old HBP lead (14 years and 3 months) and other two leads, such as passive atrial and passive right ventricular apex backup.
Anaphylaxis in children and adolescents: The Portuguese Anaphylaxis Registry
Authors: Gaspar Ângela , Santos Natacha , Faria Emília , Pereira Ana Margarida , Gomes Eva , Câmara Rita , Rodrigues‐Alves Rodrigo , Borrego Luís‐Miguel , Carrapatoso Isabel , Carneiro‐Leão Leonor , Morais‐Almeida Mário , Delgado Luís , Pedro Elisa , Branco‐Ferreira Manuel ,   Portuguese Society of Allergology and Clinical Immunology (SPAIC) Anaphylaxis Interest Group
Published: March 2021

Background

Anaphylaxis is increasing at pediatric age; however, its characterization is hampered by underdiagnosis and underreporting. The aim of this study was to identify the causes of anaphylaxis in children and adolescents in Portugal, thus contributing to a better knowledge of its etiology, clinical manifestations, and management.

Methods

During a 10‐year period, a nationwide notification system for anaphylaxis was implemented, with voluntary reporting by allergists. Data on 533 patients under 18 years of age with anaphylaxis were included.

Results

Mean age was 8.5 ± 4.9 years, 61% were male; 45% had asthma. Mean age at the first anaphylaxis episode was 5.3 ± 4.7 years (ranging from 1 month to 17 years of age), 63% at pre‐school age. Most reactions occurred at home (57%). Food‐induced anaphylaxis was the leading cause (77%). The main culprit foods were cow's milk (32%), tree nuts (16%), shellfish (13%), egg (12%), fresh fruits (11%), fish (8%), and peanut (8%). Other causes included drugs (11%), insect sting (5%), cold‐induced anaphylaxis (4%), exercise‐induced anaphylaxis (2%), latex (1%), and idiopathic anaphylaxis (1%). Most patients (83%) were admitted to the emergency department; only 46% received adrenaline treatment. Recurrence of anaphylaxis occurred in 41% of the patients (3 or more episodes in 21%). An adrenaline autoinjector was used in 9% of the patients.

Conclusions

In the Portuguese pediatric population, food is the leading cause of anaphylaxis. Undertreatment with adrenaline and high recurrence of anaphylaxis highlight the need to improve both the diagnosis and the therapeutic management of this life‐threatening entity.
Clustering Based on Kolmogorov–Smirnov Statistic with Application to Bank Card Transaction Data
Authors: Zhu Yingqiu , Deng Qiong , Huang Danyang , Jing Bingyi , Zhang Bo
Published: March 2021

Rapid developments in third-party online payment platforms now make it possible to record massive bank card transaction data. Clustering on such transaction data is of great importance for the analysis of merchant behaviours. However, traditional methods based on generated features inevitably lead to much loss of information. To make better use of bank card transaction data, this study investigates the possibility of using the empirical cumulative distribution of transaction amounts. As the distance between two merchants can be measured using the two-sample Kolmogorov–Smirnov test statistic, we propose the Kolmogorov–Smirnov K-means clustering approach based on this distance measure. An approximation step is conducted to ensure the feasibility of the proposed method even for large-scale transaction data, and the associated theoretical properties are investigated. Both simulations and an empirical study demonstrate that our method outperforms feature-based methods and is computationally efficient for large-scale data sets.
Effects of physical and cognitive training on gait speed and cognition in older adults: A randomized controlled trial
Authors: Sipilä Sarianna , Tirkkonen Anna , Savikangas Tiina , Hänninen Tuomo , Laukkanen Pia , Alen Markku , Fielding Roger A. , Kivipelto Miia , Kulmala Jenni , Rantanen Taina , Sihvonen Sanna E. , Sillanpää Elina , Stigsdotter Neely Anna , Törmäkangas Timo
Published: March 2021

Gait speed is a measure of health and functioning. Physical and cognitive determinants of gait are amenable to interventions, but best practices remain unclear. We investigated the effects of a 12‐month physical and cognitive training (PTCT) on gait speed, dual‐task cost in gait speed, and executive functions (EFs) compared with physical training (PT) (ISRCTN52388040). Community‐dwelling older adults, who did not meet physical activity recommendations, were recruited (n = 314). PT included supervised walking/balance (once weekly) and resistance/balance training (once weekly), home exercises (2–3 times weekly), and moderate aerobic activity 150 min/week in bouts of >10 min. PTCT included the PT and computer training (CT) on EFs 15–20 min, 3–4 times weekly. The primary outcome was gait speed. Secondary outcomes were 6‐min walking distance, dual‐task cost in gait speed, and EF (Stroop and Trail Making B‐A). The trial was completed by 93% of the participants (age 74.5 [SD3.8] years; 60% women). Mean adherence to supervised sessions was 59%–72% in PT and 62%–77% in PTCT. Home exercises and CT were performed on average 1.9 times/week. Weekly minutes spent in aerobic activities were 188 (median 169) in PT and 207 (median 180) in PTCT. No significant interactions were observed for gait speed (PTCT‐PT, 0.02; 95%CI −0.03, 0.08), walking distance (−3.8; −16.9, 9.3) or dual‐task cost (−0.22; −1.74, 1.30). Stroop improvement was greater after PTCT than PT (−6.9; −13.0, −0.8). Complementing physical training with EFs training is not essential for promotion of gait speed. For EF’s, complementing physical training with targeted cognitive training provides additional benefit.
Anthropology at the University of the South Pacific: From past dynamics to present perceptions
Authors: Kessler Kim Andreas
Published: March 2021

The Pacific Island region is a key context in the history of anthropology. Yet, while much has been written about how anthropology of the Pacific Islands contributed to Anglo‐American anthropology, the discipline's institutional history in the Pacific Islands has received very little attention. This paper is the first to explore the history of anthropology at the University of the South Pacific (USP). Research findings demonstrate that anthropology lacked practical meaning in an institution established to modernise Pacific Island states. Fieldwork conducted at USP suggests that current perceptions of anthropology held by academic staff are strongly linked to the discipline's classic era. I argue that the anti‐colonial version of the Pacific Way from the 1970s onward, coupled with the hegemony of political economist and anti‐culturalist approaches among the USP teaching staff in the 1980s, inhibited a meaningful engagement with the Writing Culture debate at USP. This may explain why there has been little influence by the discipline's postmodern transformation over the past thirty years on current perceptions of anthropology at USP.
Narratives of resistance and decolonial futures in the politics of the Bermudian Black Power movement
Authors: Gowland Ben
Published: March 2021

In this paper, I examine the spatial politics of the Bermudian Black Power movement and its connections to Black Power political formations in the wider Caribbean and North America. This spatial politics is examined in detail through an engagement with the First Regional International Black Power Conference (BPC) held in Bermuda on 10–13 July 1969 and the subsequent Black Power political activity on the island that the conference inspired. Through this engagement it is shown how the island of Bermuda and its black population were constitutive of transnational circulations of radical Black Power, and aligned thinkers and activists. This paper develops a reading of a politics of Black Power on the island as challenging hegemonic geographies and political spatialities of white supremacy through the envisioning of alternative, decolonial futures and a resultant pre‐figurative political praxis. Such a reading is built on the theory of West Indian scholars David Scott and Brian Meeks and the spatial ontology of Doreen Massey. D. Scott and Meeks have been key contributors to Caribbean critical thought for many decades, with D. Scott the long‐time editor of the Caribbean studies journal Small Axe, and both have been concerned with post and de‐colonial politics in the region and the role of temporality and historiography in conceptualisations of the Modern Caribbean and Jamaica in particular. This paper offers an exploration of a decolonial spatial politics and political praxis, through the theory of post‐colonial Caribbean intellectuals, that foregrounds the agentive and insurgent capacity of Black Power as a political movement in the imagining and pre‐figuration of emancipatory futures beyond hegemonic geographies of white supremacy, (neo)colonialism, and (neo)imperialism.
Resolving the species status of overlooked West‐Palaearctic bumblebees
Authors: Brasero Nicolas , Ghisbain Guillaume , Lecocq Thomas , Michez Denis , Valterová Irena , Biella Paolo , Monfared Alireza , Williams Paul Hugh , Rasmont Pierre , Martinet Baptiste
Published: March 2021

Multisource approaches in taxonomy gather different lines of evidence in order to draw strongly supported taxonomic conclusions and constitute the basis of integrative taxonomy. In the case of overlooked taxa with disjunct distributions for which sampling is more challenging, integrative approaches help to propose stable hypotheses at the species and subspecies levels. Here, based on genetic and semio‐chemical traits, we performed an integrative taxonomic analysis to evaluate species delimitation hypotheses within a monophyletic group of bumblebees (Hymenoptera, Apidae, Bombus) including the formerly recognised subgenera Eversmannibombus, Laesobombus and Mucidobombus which are now included in the subgenus Thoracobombus. Our results demonstrate the conspecificity of several polytypic taxa, and we formally recognise the subspecies Bombus laesus aliceae comb. nov. Cockerell, 1931, endemic to North Africa, based on its allopatry, unique mitochondrial haplotype and divergent cephalic labial gland secretions. This highlights the need to maintain studying polytypic complexes of bumblebee taxa for which phylogenetic relationships could be still entangled and eventually implement conservation strategies for taxonomically differentiated lineages.
Verification of ansys and matlab Heat Conduction Results Using an “Intrinsically” Verified Exact Analytical Solution
Authors: McMasters Robert L. , de Monte Filippo , D'Alessandro Giampaolo , Beck James V.
Published: March 2021

A two-dimensional (2D) transient thermal conduction problem is examined, and numerical solutions to the problem generated by ansys and matlab, employing the finite element (FE) method, are compared against an “intrinsically” verified analytical solution. Various grid densities and time-step combinations are used in the numerical solutions, including some as recommended by default in the ansys software, including coarse, medium, and fine spatial grids. The transient temperature solutions from the analytical and numerical schemes are compared at four specific locations on the body, and time-dependent error curves are generated for each point. Additionally, tabular values of each solution are presented for a more detailed comparison. Two different test cases are examined for the various numerical solutions using selected grid densities. The first case involves uniform constant heating on a portion of one surface for a long duration, up to a dimensionless time of 30. The second test case still involves uniform constant heating but for a dimensionless time of one, immediately followed by an insulated condition on that same surface for another duration of one dimensionless time unit. Although the errors at large times for both ansys and matlab are extremely small, the errors found within the short-duration test are more significant, in particular when the heating is suddenly set “on.” Surprisingly, very small errors occur when the heating is suddenly set “off.” The solution developed using the matlab differential equation solver is found to have errors an order of magnitude larger than those generated using ansys with a similar mesh size and same FE type (quadratic triangular). This occurs not only during the transient but also for steady-state problems. However, the matlab computational efficiency is superior. Also, when using ansys, at early times the numerical errors are very sensitive to the time-step chosen rather than the spatial discretization. Therefore, the time-steps have to be very small near a singularity.
Near Tip Loss Control With a Winglet Baffle Cavity Tip in a Turbine Cascade
Authors: Li Li , Jiang Dengyu , Zhou Chao , Luo Hualing , Hou Weitao , Chang Qiyue
Published: March 2021

The aerodynamic performance of a winglet baffle cavity tip is investigated at different inlet incidences from −12.5 to +12.5 deg. This blade tip shows a geometry feature with a pressure side winglet and a baffle within the tip cavity. The experimental studies were carried out in a large-scale linear cascade. Numerical methods were also used to obtain the detail flow physics. The baffle on the tip divides the cavity vortex into two main parts, and enhances flow mixing over the tip. As the tip leakage flow exits the tip near the baffle and the cavity corner, flow separation occurs over the suction side and its blockage effect reduces the local tip leakage mass flow rate. The additional pressure side winglet reduces the contraction coefficient on the pressure side squealer. Compared with the squealer tip, the winglet baffle cavity tip reduces the tip leakage mass flow by 12.1% and the near tip loss by 4.2%. Removing the baffle on the tip also results in an increase of the loss. As the incidence of the incoming flow decreases, the loss near the tip reduces mainly due to a reduction of the strength of the passage vortex, which develops from the casing endwall. At all incidences studied, the winglet baffle cavity tip shows better aerodynamic performance than the squealer tip.
The Impact of the Human Body Position Changes During Wheelchair Propelling on Motion Resistance Force: A Preliminary Study
Authors: Wieczorek Bartosz , Kukla Mateusz , Warguła Łukasz , Rybarczyk Dominik , Giedrowicz Marcin , Górecki Jan
Published: March 2021

The aim of this research was to analyze the impact of the human body position changes caused by propelling a wheelchair with the pushrim propulsion on the value of motion resistance force. The discussed research works are in progress; therefore, the presented results should be treated as preliminary. The research was carried out in the group of six volunteers propelling a wheelchair of which frame was inclined, in respect to the horizontal plane, under the angle of 0 deg, 7 deg, and 14 deg. The area of the position variability of the human body center of gravity (COG) and the coefficients of wheelchair rolling resistance have been determined. Based on the measurements conducted, rolling resistance force FT and motion resistance force FR have been defined for three values of frame inclination angle. The determined force of rolling resistance Ft depended on the location of the COG of the human body and the value of the coefficients of rolling resistance of the front and rear wheels of a wheelchair. This force was a component of the resistance to motion FR, which also took into account the influence of gravity resulting from the inclination of the wheelchair on an inclined plane. For the tested inclination angles relative to the horizontal plane, the rolling resistance force ranged from 9.82 N to 22.81 N. Analyzing the variability of the rolling resistance force FT, it was found that for the final phase of the driving motion, it increased by 36% for the inclination angle of 0 deg and 43% for the inclination angle of 7 deg. Its increase was 48% for the inclination angle of 14 deg in relation to the human body position for the beginning of the driving motion. In the case of measuring the value of the resistance to motion FR, it was observed that, depending on the angle of the incline of the wheelchair, it ranged from 14.69 N to 256.33 N. The measurements conducted enabled the derivation of an analytical model for determining rolling resistance force depending on the position of the human body COG and the wheelchair inclination angle. The conducted research demonstrated the impact of the COG position on the changes of motion resistance force, thus expanding the state of knowledge, introducing a new parameter which, like a surface type and wheel type, affects motion resistances.
Statically Balancing a Reconfigurable Mechanism by Using One Passive Energy Element Only: A Case Study
Authors: Kuo Chin-Hsing , Nguyen Vu Linh , Robertson Daniel , Chou Lin-Tien , Herder Just L.
Published: March 2021

This paper presents the static balancing design of a special reconfigurable linkage that can switch between two one-degree-of-freedom (DoF) working configurations. We will show that the studied dual-mode linkage only requires one mechanical spring or one counterweight for completely balancing its gravitational effect in theory at both modes. First, the theoretical models of the spring-based and the counterweight-based designs are derived. The proposed design concepts were then demonstrated by a numerical example and validated by software simulation. Experimental tests on both designs were also performed. The result of this study shows that a reconfigurable mechanism with N working configurations can be completely statically balanced by using less than N passive energy elements.
A Heuristic Application-Specific Path Planner for Robot Motion Planning
Authors: Alciatore David G.
Published: March 2021

This paper presents the development and simulation results of a Heuristic Application-Specific Path Planner (HASPP) that can be used to automatically plan trajectories for a manipulator operating around obstacles. Since the implementation of HASPP is inherently application-specific due to dependence on heuristics, the application of HASPP to an eight degree of freedom Pipe Manipulator is presented as an illustrative example. This development and simulation was implemented on a Silicon Graphics Personal IRIS with the aid of WALKTHRU, a 3-D simulation and animation tool, and software developed in C. HASPP uses extensive knowledge of the manipulator’s workspace and makes certain assumptions about the environment in finding trajectories. The algorithm also makes use of the manipulator’s redundant degrees of freedom to avoid obstacles and joint limits during the trajectory while obtaining a heuristic near-optimal solution. The algorithm is rule-based, governed by heuristics and well-defined geometric tests, providing extremely fast results. It finds “good” trajectories that are optimal within the defined heuristics. When a trajectory is not feasible for the given geometry, the algorithm offers a diagnosis of the limiting constraints.

The Pipe Manipulator HASPP implementation has been tested thoroughly with the computer graphics model and it has demonstrated the ability to reliably determine near-optimal collision-free erection trajectories completely automatically. No other planning techniques available in the literature have demonstrated the ability to solve problems as complex as the example presented here. The use of HASPP with simulation offers many application opportunities including plant design constructability studies, assembly and maintenance planning, pre-planning and pre-programming of equipment tasks, and equipment operator assistance. This work was the result of construction automation research sponsored by the National Science Foundation.
Rapid Prototyping: Cornerstone of the New Design Process
Authors: Ulerich Phillip L.
Published: March 2021

A new design process is being developed incorporating engineers designing in 3D on workstations, solid modeling, computerized design data bases and networks, finite element analysis, rapid prototyping, and rapid tooling, the critical issue for us is to get new product parts and assemblies as soon as possible and the cornerstone of our approach for molded parts is rapid prototyping for the initial parts and short run tooling.

The author discusses his experience over the last three years designing molded case circuit breakers with the new design process, including successes and failures of over 20 stereolithography parts and half a dozen spray metal molds. These processes alone have a significant effect on the design cycle time but the really big payoff comes when they are incorporated in an entirely new approach to mechanical design.
A Method for Selecting Measurement Points on Planar Faces of Objects With Holes
Authors: Vardar Hayri O. , Ozsoy Tulga M.
Published: March 2021

In this paper, a method facilitating the automatic selection of measurement points on planar faces of objects with holes will be presented. The objective is to further automate the process of generation of inspection programs for coordinate measuring machines.

The method developed aims for the creation of candidate points on a planar face of an object and the optimal selection of a required number of measurement points among the candidate points. A triangulation technique based on a finite element mesh generation method has been implemented in creating the candidate points. Except for the special case of four points, a random selection process is utilized for choosing among the candidate points. The effects of randomness are compensated by applying a convex hull computation algorithm to find the set of points among other candidate sets that covers the largest area. The method has been successfully incorporated into a software demonstrating the feasibility of the approach.
Interfacing PATRAN or ANSYS Programs to FIDAP for Analysis of Realistic Engineering Problems
Authors: Jamnia Mohammad Ali , Chu William
Published: March 2021

With the recent advances in the various fields of engineering and the fields of computer hardware and software, a large number of computer programs are being used as design tools in the area of manufacturing. These tools generally deal with parameters and variables specific to one particular area. For instance, a solid mechanic code is equipped with means of specifying forces and displacements and a program designed for magnetics analysis can only have input/output related to magnetics. However, in many realistic systems, a number of these various fields are present and effective design requires coupling of these variables.
Best-Estimate Analysis of Loss-of-Coolant Accident in Pressurized Heavy Water Reactors Using Microcomputers
Authors: Saha P. , Das T. K. , Chanda A. , Ray S.
Published: March 2021

The present paper discusses the development of a computer software or code for best-estimate analysis of Loss-of-Coolant Accident (LOCA) in Pressurized Heavy Water Reactor (PHWR) systems. The formulation is comparable to U.S., Canadian, French LOCA codes, namely, TRAC, RELAPS, ATHENA, CATHARE, etc. However, the present software has been developed on Microcomputers, namely, PC-XT and AT, whereas the other softwares were developed and are being used primarily on Mainframes such as CDC-7600, CYBER-176, CRAY, etc.
An Intelligent Mathematical Modelling Assistant for Analysis of Physical Systems
Authors: Finn D. P. , Grimson J. B. , Harty N. M.
Published: March 2021

This paper describes work in progress aimed at developing an intelligent modelling assistant for the mathematical modelling task associated with engineering analysis. Mathematical modelling precedes detailed numerical analysis and involves formulating and evaluating engineering problems with the objective of proposing a candidate mathematical model that meets desired modelling requirements. The approach taken in this work is based on Chandrasekaran’s proposecritique-modify method which is adapted for modelling. The use of this paradigm is justified by viewing the mathematical modelling process as an activity of successive investigation and refinement of candidate mathematical models. The system architecture is based on exploiting a number of artificial intelligence techniques including model based reasoning, case based reasoning and rule based reasoning. A modelling options case base assists engineers in proposing candidate mathematical models. Engineering 1st principles and formulae are utilised within an artificial intelligence framework to provide a means of evaluating and critiquing the candidate mathematical models. The system is integrated with an existing interactive CAD system. The problem domain covered is application independent but will initially focus on the modelling and analysis of heat transfer problems.
Implementation of an Efficient Description of Elastic Properties of a Layered Composite in a Finite Element
Authors: Patton Edward M.
Published: March 2021

A constitutive formulation for a layered composite originally proposed by Christensen (1) is implemented in a displacement-based three dimensional isoparametric finite element. The element is tested against the much studied free-edge stress problem, and is found, in general, to have good agreement with published results using a single element through the thickness of the laminate, even in the vicinity of the free edge. In-plane stresses and through thickness normal stresses agree extremely well with previous results. The results for interlaminar shear stress are, however, somewhat lower than previously published. Reasons for this discrepancy are discussed.
Techniques for the Development of an Audiographic Teleconferencing Course
Authors: Hotchkiss Anthony
Published: March 2021

The development and preparation of course material for audiographic teleconferencing, a form of distance education, is discussed. The Group Teleconferencing System (GTCS), used at the University of Wisconsin-Madison, is described. GTCS allows visual material (slides) to be displayed and annotated interactively, and some techniques for the generation and presentation of the slides are suggested, using a computer-aided-design course as an example.
Effect of Contact Ratio on Spur Gear Dynamic Load
Authors: Liou Chuen-Huei , Lin Hsiang Hsi , Oswald Fred B. , Townsend Dennis P.
Published: March 2021

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant.

The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than 2.0), increasing the contact ratio reduced the gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.
Studies on the Dynamic Performance of a Spur Gear With Hollow Teeth
Authors: Ramamohana Rao A. , Srinivasulu B.
Published: March 2021

Performance of spur gears largely depends on the magnitude and nature of variation of dynamic loads occuring between mating teeth. Variable tooth mesh stiffness is one of the primary sources causing parametric excitations resulting in dynamic loads. The usual method of varying the mesh stiffness to reduce dynamic loads is to use high contact ratio and profile modified gears. In this paper, a new type of tooth design to improve the dynamic performance of spur gears is presented. In this, a through hole is drilled in each tooth in a direction parallel to the gear axis. The diameter of the hole and its position on the tooth centre line are variable. Such a gear is called a hollow gear. Dynamic analysis is carried out for the mesh of hollow pinions mating with solid gears. The results are compared with solid pinions (no holes in teeth) meshing with solid gears. Finite element method is used for the analysis.

For estimation of the dynamic load variation in hollow-solid and solid-solid gear meshes, a model incorporating the varying mesh stiffness and damping of gear teeth is used. Governing differential equations are solved using unconditionally stable Newmark-beta algorithm. The dynamic loads obtained are used as an input time varying loads for the determination of dynamic fillet and hole stress response of solid and hollow gear teeth whichever is applicable. Modal superposition technique is used for transient response analysis. The study shows that for the same damping ratio, dynamic loads in hollow-solid meshes are nearly the same as in a solid-solid mesh. In reality, the dynamic loads in a hollow-solid mesh are less than a solid-solid mesh due to its inherent higher material damping.
Gear Tooth Stress Measurements of Two Helicopter Planetary Stages
Authors: Krantz Timothy L.
Published: March 2021

Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at the NASA Lewis Research Center. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through the mesh are illustrated. At the tooth root location of the thin-rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three-planet, nonsequential design as compared to that of a four-planet, sequential design. The results reported enhance the data base for gear stress levels and provide data for the validation of analytical methods.
Transmission Analysis: Automatic Derivation of Relationships
Authors: Hedman Anders
Published: March 2021

A method for derivation of relationships for general mechanical transmission systems is given. The method is adapted for computer aided analysis and synthesis of the kinematics, loads and power flows. Losses are included. All relationships are handled by a computer program. No manual formulation and elimination of equations are necessary. The user only needs to describe the transmission system:

1. The transmission units, e.g. gear transmissions, planetary gear trains, clutches, input and output shafts.

2. How the shafts of those units are connected.

Then, the computer program formulates and arranges the relationships. After that, a commercial program, “Maple”, performs the algebraic eliminations. Relationships between the speeds and/or torques of two arbitrary shafts can be derived, e.g. an algebraic relationship for the overall efficiency. Different power flows are possible in split-power transmissions. Special algorithms handle that. The method is a useful tool. It saves time and eliminates the risk for human errors.
Effects of Assembly and Manufacturing Errors on Transmission Error of Planetary Gears
Authors: Ishida Takeshi , Hidaka Teruaki
Published: March 2021

Transforming 2K-H type planetary gears with three planet gears into an equivalent model with many degrees of freedom, in a plane perpendicular to the input and output shafts, the loci of the displacement of a floating sun gear were analyzed theoretically by using the equivalent model. The theoretical locus of the displacement of the sun gear was nearly identical to the experimental one.

K-H-V type planetary gears have been used as the reduction gears in the industrial robot, and have desired to decrease the transmission error between the input and output shafts for increasing the positioning accuracy of the robot. The K-H-V type planetary gears composed of a sun gear for the input, three planet gears, three crankshafts, two disks with cycloidal teeth, an internal gear with pin type teeth, and a carrier for the output were also transformed into the equivalent model in the same manner as the 2K-H planetary gears, and the effects of manufacturing and assembly errors of elements on the transmission error were determined theoretically.