bluuebunny/crossref_metadata_2025 huggingface dataset:
Do self‐reported hearing and visual impairments predict longitudinal dementia in older adults?
Authors: Pabst Alexander , Bär Jonathan , Röhr Susanne , Löbner Margrit , Kleineidam Luca , Heser Kathrin , Hajek André , van der Leeden Carolin , Wiese Birgitt , Maier Wolfgang , Angermeyer Matthias C. , Scherer Martin , Wagner Michael , König Hans‐Helmut , Riedel‐Heller Steffi G.
Published: March 2021

Background

Sensory impairments have been associated with dementia in older adults. However, the contribution of different impairments and how they interact in the development of dementia is not clear. We examined the independent and interaction effects of hearing impairment (HI) and visual impairment (VI) on incident dementia.

Design

Multi‐centric population‐based prospective cohort study.

Setting

Data were taken from the AgeDifferent.de platform, pooling participants aged 75 and older from the German LEILA75+ and AgeCoDe/AgeQualiDe cohorts.

Participants

Older adults (N = 3497) with mean age 79.8 years, 67.2% female.

Measurements

Standardized interviews and questionnaires were used to assess self‐reported HI and VI at baseline and all‐cause dementia in 9 follow‐ups, spanning over 20 years.

Methods

Competing risk regression models were conducted to test the main and interaction effects of HI and VI on dementia incidence, adjusting for established risk factors of dementia and accumulated mortality.

Results

HI and VI at baseline were reported by 30.3% and 16.6% of individuals, respectively. Adjusting for baseline information on sociodemographics, substance use, cognitive functioning and morbidity, and controlling for accumulated mortality risk, HI (sHR 1.16, 95% CI 1.04–1.30, p = 0.011) but not VI (sHR 1.07, 95% CI 0.90–1.28, p = 0.462) was significantly associated with incident dementia. There was no interaction between HI and VI (sHR 1.09, 95% CI 0.81–1.46, p = 0.567).

Conclusions

Hearing impairment is associated with an increased incidence of all‐cause dementia in older adults. There is no excess risk or risk compensation through the additional presence or absence of visual impairment. Early prevention measures for hearing impairment might help to reduce the long‐term risk of dementia.
Practicing Emotionally Focused Therapy online: Calling all relationships
Authors: Allan Robert , Wiebe Stephanie A. , Johnson Susan M. , Piaseckyj Olena , Campbell T. Leanne
Published: March 2021

In the midst of a global pandemic, couples are dealing a range of impacts that call for a cohesive unit while the virus frays at the edges of our most important relationships. Emotionally Focused Therapy (EFT) is an evidence‐based approach to working with relationships rooted in attachment theory. As a process‐oriented psychotherapy, EFT is an ideal approach to working with relationships during this pandemic helping to solidify an “in it together” approach required to survive both as a couple and the pandemic. In this paper, we briefly review the adaptations for moving a couple therapy practice online through an EFT lens, drawing on an EFT macro‐intervention called the “Tango” as a focus in this process. We conclude the paper with a case example providing the reader with an illustration of the process and ideas for what to pay attention to when working online with a couple from an EFT perspective.
A hypomyelinating leukodystrophy in German Shepherd dogs
Authors: Quitt Pia R. , Brühschwein Andreas , Matiasek Kaspar , Wielaender Franziska , Karkamo Veera , Hytönen Marjo K. , Meyer‐Lindenberg Andrea , Dengler Berett , Leeb Tosso , Lohi Hannes , Fischer Andrea
Published: March 2021

Background

Shaking puppy syndrome is commonly attributed to abnormal myelination of the central nervous system.

Hypothesis/Objectives

To report the long‐term clinical course and the imaging characteristics of hypomyelinating leukodystrophy in German Shepherd dogs.

Animals and Methods

Three related litters with 11 affected dogs.

Results

The 11 affected dogs experienced coarse, side‐to‐side tremors of the head and trunk, which interfered with normal goal‐oriented movements and disappeared at rest. Signs were noticed shortly after birth. Nine dogs were euthanized, 3 dogs underwent pathological examination, and 2 littermates were raised by their breeder. Tremors improved gradually until 6 to 7 months of age. Adult dogs walked with severe residual pelvic limb ataxia. One dog developed epilepsy with tonic‐clonic seizures at 15 months of age. Conventional magnetic resonance imaging (MRI) disclosed homogenous hyperintense signal of the entire subcortical white matter in 3 affected 7‐week‐old dogs and a hypointense signal in a presumably unaffected littermate. Subcortical white matter appeared isointense to gray matter at 15 and 27 weeks of age on repeated MRI. Abnormal white matter signal with failure to display normal gray‐white matter contrast persisted into adulthood. Cerebellar arbor vitae was not visible at any time point. Clinical signs, MRI findings, and pathological examinations were indicative of a hypomyelinating leukodystrophy. All parents of the affected litters shared a common ancestor and relatedness of the puppies suggested an autosomal recessive mode of inheritance.

Conclusion

We describe a novel hypomyelinating leukodystrophy in German Shepherd dogs with a suspected inherited origin.
Shape and porosity of refractory inclusions in CV3 chondrites: A micro‐computed tomography (µCT) study
Authors: Zhang Mingming , Clark Brett , King Ashley J. , Russell Sara S. , Lin Yangting
Published: March 2021

Refractory calcium‐aluminum‐rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs) in chondritic meteorites are the earliest solids of our solar system, bearing the information of nebular condensation as well as accretion and asteroidal shock and metasomatism processes. While the compositions of refractory inclusions have been intensely studied for ~50 years, their physical properties such as shape and porosity are poorly constrained. Here, we present a microcomputed tomography (µCT) study on 16 refractory inclusions of condensate origin in five CV3 chondrites. We find that they are prolate or triaxial in shape with very rough morphologies. The CAIs have nodular textures and are thought to form by agglomerating individual nodules via collision‐induced bouncing and/or fragmentation, where the nodules were grown by gas–solid reactions during condensation. On the parent body, refractory inclusions from the CVR meteorite Leoville experienced intense shocks that led to the flattening of their shapes and lowering of their porosities. High‐temperature metasomatism in CVOxA meteorites and low‐temperature metasomatism in CVOxB meteorites do not seem to have large effects on the porosities of their refractory inclusions, which have similar ranges and pore‐size distributions. Instead, we infer that their pores are mostly inherited from the gas–solid condensation and subsequent agglomeration processes. The porosities of CAIs are higher than those of AOAs, which is mainly due to the high‐temperature sintering process of AOAs.
“I don't let everyone see my struggles”: Mothers' social support and privacy management
Authors: Vik Tennley A. , DeGroot Jocelyn M.
Published: March 2021

This study explored the connection between communication privacy management and person‐centered messages directed toward mothers, as they make decisions to disclose or not disclose parenting challenges in the face of needing social support. One hundred thirty‐six mothers completed the online open‐ended survey. Findings revealed that, if they chose to share their challenges, mothers tended to disclose parenting challenges to others with whom they identified. Reasons for reifying rigid privacy boundaries include maintaining positive self‐presentation, buffering from judgment of others, the anticipation of low person‐centered messages, and experiences with others constructing hurtful social support messages. Participants also reflected on their experiences and identified their own social support needs.
Can entrepreneurial orientation improve R&D alliance performance? An absorptive capacity perspective
Authors: Seo Ribin , Edler Jakob , Massini Silvia
Published: March 2021

Research and Development (R&D) alliance studies maintain that alliance partners’ entrepreneurial interactions that pursue innovation opportunities through collective exploitation and exploration of knowledge resources lead to alliance success. Despite the importance of productive resource exchange and generation through such interactions, performance‐by‐alliance mechanisms remain under‐researched. In this study, we develop a theoretical framework hypothesizing that the entrepreneurial orientation (EO) of alliance firms, which underlies their approach to seeking and utilizing resources productively, has a potential impact on their R&D alliance performance, depending on their absorptive capacity (AC). To specify the value creation and capture mechanism in the alliance, we adopt two performance indicators: technological competitiveness and business performance. Findings from a study of 218 small technology‐intensive firms conducting R&D alliance projects show that EO translates into business performance through technological competitiveness and that AC leverages the alliance performance implications of EO. The results suggest that EO–AC complementarity is a strategic stimulant that triggers firms to extract greater benefits from R&D alliances.
Analyzing the Risk to COVID‐19 Infection using Remote Sensing and GIS
Authors: Kanga Shruti , Meraj Gowhar , Sudhanshu  , Farooq Majid , Nathawat M. S. , Singh Suraj Kumar
Published: March 2021

Globally, the COVID‐19 pandemic has become a threat to humans and to the socioeconomic systems they have developed since the industrial revolution. Hence, governments and stakeholders call for strategies to help restore normalcy while dealing with this pandemic effectively. Since till now, the disease is yet to have a cure; therefore, only risk‐based decision making can help governments achieve a sustainable solution in the long term. To help the decisionmakers explore viable actions, we propose a risk‐based assessment framework for analyzing COVID‐19 risk to areas, using integrated hazard and vulnerability components associated with this pandemic for effective risk mitigation. The study is carried on a region administrated by Jaipur municipal corporation (JMC), India. Based on the current understanding of this disease, we hypothesized different COVID‐19 risk indices (C19Ri) of the wards of JMC such as proximity to hotspots, total population, population density, availability of clean water, and associated land use/land cover, are related with COVID‐19 contagion and calculated them in a GIS‐based multicriteria risk reduction method. The results showed disparateness in COVID‐19 risk areas with a higher risk in north‐eastern and south‐eastern zone wards within the boundary of JMC. We proposed prioritizing wards under higher risk zones for intelligent decision making regarding COVID‐19 risk reduction through appropriate management of resources‐related policy consequences. This study aims to serve as a baseline study to be replicated in other parts of the country or world to eradicate the threat of COVID‐19 effectively.
Frequent blood flow restricted training not to failure and to failure induces similar gains in myonuclei and muscle mass
Authors: Bjørnsen Thomas , Wernbom Mathias , Paulsen Gøran , Berntsen Sveinung , Brankovic Robert , Stålesen Håkon , Sundnes Joakim , Raastad Truls
Published: March 2021

The purpose of the present study was to compare the effects of short‐term high‐frequency failure vs non‐failure blood flow–restricted resistance exercise (BFRRE) on changes in satellite cells (SCs), myonuclei, muscle size, and strength. Seventeen untrained men performed four sets of BFRRE to failure (Failure) with one leg and not to failure (Non‐failure; 30‐15‐15‐15 repetitions) with the other leg using knee‐extensions at 20% of one repetition maximum (1RM). Fourteen sessions were distributed over two 5‐day blocks, separated by a 10‐day rest period. Muscle samples obtained before, at mid‐training, and 10‐day post‐intervention (Post10) were analyzed for muscle fiber area (MFA), myonuclei, and SC. Muscle size and echo intensity of m.rectus femoris (RF) and m.vastus lateralis (VL) were measured by ultrasonography, and knee extension strength with 1RM and maximal isometric contraction (MVC) up until Post24. Both protocols increased myonuclear numbers in type‐1 (12%–17%) and type‐2 fibers (20%–23%), and SC in type‐1 (92%–134%) and type‐2 fibers (23%–48%) at Post10 (p < 0.05). RF and VL size increased by 5%–10% in both legs at Post10 to Post24, whereas the MFA of type‐1 fibers in Failure was decreased at Post10 (−10 ± 16%; p = 0.02). Echo intensity increased by ~20% in both legs during Block1 (p < 0.001) and was ~8 to 11% below baseline at Post24 (p = 0.001–0.002). MVC and 1RM decreased by 5%–10% after Block1, but increased in both legs by 6%–11% at Post24 (p < 0.05). In conclusion, both short‐term high‐frequency failure and non‐failure BFRRE induced increases in SCs, in myonuclei content, muscle size, and strength, concomitant with decreased echo intensity. Intriguingly, the responses were delayed and peaked 10–24 days after the training intervention. Our findings may shed light on the mechanisms involved in resistance exercise‐induced overreaching and supercompensation.
Building Populist Discourse: An Analysis of Populist Communication in American Presidential Elections, 1896–2016
Authors: Fahey James J.
Published: March 2021

Objectives

This article examined the history of the use of populist frames in American presidential campaign discourse in order to answer a set of interrelated questions about how populist discourse is constructed and employed.

Methods

Using a novel database of presidential campaign speeches (n = 189) from 63 major candidates from 1896 to 2016, I coded these speeches for presence or absence of a set of 11 populist frames. Mokken scale analysis was conducted to determine if populist discourse is “built” in a logical way by political candidates. Regression analysis was conducted to measure if outsider candidates were more likely to employ populist framing.

Results

Eight of the 11 frames comprise a stable Mokken scale that measures populist discourse. Results show that anti‐bureaucratic and nativist frames do not load onto the same factor as other populist frames, suggesting that they may be measuring a separate concept. Candidates are more likely to use generic, less threatening aspects of the populist frame than they are to use illiberal, “risky” frames. Less experienced and third‐party candidates are also more likely to use populist discourse.

Conclusion

Populism is a flexible but coherent set of discursive frames present across modern campaign history. Populist framings are most commonly utilized by outsider candidates.
Manganese triggers phosphorylation‐mediated endocytosis of the Arabidopsis metal transporter NRAMP1
Authors: Castaings Loren , Alcon Carine , Kosuth Thibault , Correia David , Curie Catherine
Published: March 2021

The NATURAL RESISTANCE‐ASSOCIATED MACROPHAGE PROTEIN 1 (NRAMP1) transporter guarantees plant survival of manganese (Mn) deficiency by mediating Mn entry into root cells. Unlike other high‐affinity metal transporters, NRAMP1 is only slightly regulated at the transcriptional level. We show here that adequate Mn content in tissues is safeguarded through a tight control of the quantity of NRAMP1 present at the surface of root cells. Depending on Mn availability, an NRAMP1‐GFP fusion protein cycles dynamically between the plasma membrane (PM) and endosomal compartments. This involves a clathrin‐mediated endocytosis pathway, as disrupting this pathway in auxilin‐overexpressor lines prevents NRAMP1 internalization. Mutation of the phosphorylated serine residues 20, 22 and 24 in the cytosol‐exposed N terminus of NRAMP1 alters its membrane distribution. Indeed, a phospho‐dead mutation stabilizes NRAMP1 at the PM, regardless of the Mn regime, and dramatically reduces plant tolerance to Mn toxicity. Conversely a phosphomimetic mutant is constitutively internalized into endosomes. Together, these data establish that phosphorylation of NRAMP1 is the trigger for its Mn‐induced endocytosis and represents the main level of regulation of this transporter. Furthermore, the extent of Mn toxicity observed when interrupting NRAMP1 membrane cycling undermines the dogma that Mn is only marginally toxic to plants.
The BOP‐type co‐transcriptional regulator NODULE ROOT1 promotes stem secondary growth of the tropical Cannabaceae tree Parasponia andersonii
Authors: Shen Defeng , Holmer Rens , Kulikova Olga , Mannapperuma Chanaka , Street Nathaniel R. , Yan Zhichun , van der Maden Thomas , Bu Fengjiao , Zhang Yuanyuan , Geurts Rene , Magne Kévin
Published: March 2021

Tree stems undergo a massive secondary growth in which secondary xylem and phloem tissues arise from the vascular cambium. Vascular cambium activity is driven by endogenous developmental signalling cues and environmental stimuli. Current knowledge regarding the genetic regulation of cambium activity and secondary growth is still far from complete. The tropical Cannabaceae tree Parasponia andersonii is a non‐legume research model of nitrogen‐fixing root nodulation. Parasponia andersonii can be transformed efficiently, making it amenable for CRISPR‐Cas9‐mediated reverse genetics. We considered whether P. andersonii also could be used as a complementary research system to investigate tree‐related traits, including secondary growth. We established a developmental map of stem secondary growth in P. andersonii plantlets. Subsequently, we showed that the expression of the co‐transcriptional regulator PanNODULE ROOT1 (PanNOOT1) is essential for controlling this process. PanNOOT1 is orthologous to Arabidopsis thaliana BLADE‐ON‐PETIOLE1 (AtBOP1) and AtBOP2, which are involved in the meristem‐to‐organ‐boundary maintenance. Moreover, in species forming nitrogen‐fixing root nodules, NOOT1 is known to function as a key nodule identity gene. Parasponia andersonii CRISPR‐Cas9 loss‐of‐function Pannoot1 mutants are altered in the development of the xylem and phloem tissues without apparent disturbance of the cambium organization and size. Transcriptomic analysis showed that the expression of key secondary growth‐related genes is significantly down‐regulated in Pannoot1 mutants. This allows us to conclude that PanNOOT1 positively contributes to the regulation of stem secondary growth. Our work also demonstrates that P. andersonii can serve as a tree research system.
A Review on Water Fault Diagnosis of a Proton Exchange Membrane Fuel Cell System
Authors: Ma Tiancai , Zhang Zhaoli , Lin Weikang , Yang Yanbo , Yao Naiyuan
Published: March 2021

Reliability and durability are the main factors that hinder the large-scale commercialization of proton exchange membrane fuel cell (PEMFC). Water management is the key to solve such problems, and water content is the measurement standard of water management. But it is very difficult to measure water content inside the fuel cell directly. Thus, water fault diagnosis is a basic technology to monitor the water content indirectly based on the measurable parameters. In this paper, the water fault diagnosis of the PEMFC system has been summarized in three sections including the theoretical model-based method, knowledge-based method, and signal processing method from practical application, and part of them is from the perspective of vehicle application.
Pressure Loss Due to Hydraulic Transport of Large Solid Particles in Vertical Pipes Under Pulsating Flow Conditions
Authors: Masanobu Sotaro , Takano Satoru , Kanada Shigeo , Ono Masao
Published: March 2021

It is important to predict the pressure loss due to hydraulic transport of large solid particles for the design of subsea mining system. The mixture flow in the lifting pipe is expected to be unsteady in the actual mining system. The authors develop the one-dimensional mathematical model to predict the pressure loss of pulsating mixture flow in a static vertical pipe assuming that the flow in the pipe is fully developed. The experiment on hydraulic transport of solid particles was carried out to obtain the data for the investigation of the effects of flow fluctuation on pressure loss in a static vertical pipe. In the experiment, alumina beads and glass beads were used as solid particles, and the experimental parameters were mixture velocity, solid concentration, pulsating period, and pulsating amplitude. The proposed model was validated by a comparison with experimental data. Furthermore, we calculated the pressure losses due to hydraulic transports of polymetallic sulfide ores and manganese nodules using the proposed model. The calculation results showed that the fluctuating component in pulsating mixture flow should be considered for the design of lifting system and that the homogeneous mixture model could not be applied to the prediction of the pressure loss unless the mixture concentration is low and the pulsating period is short.
Short-Term Forecasting and Uncertainty Analysis of Wind Power
Authors: Bo Gu , Keke Luo , Hongtao Zhang , Jinhua Zhang , Hui Huang
Published: March 2021

Accurate forecasting is the key factor in promoting wind power consumption and improving the stable operation of power systems. A short-term wind power forecasting (WPF) and uncertainty analysis method based on whale optimization algorithm (WOA), least squares support vector machine (LSSVM), and nonparametric kernel density estimation (NPKDE) was proposed in this paper. The advantages of WOA (fast convergence speed and high convergence accuracy) were used to optimize the penalty factor and kernel function width of the LSSVM model, and the calculation speed and forecasting accuracy of the LSSVM model were improved. The training sample set is classified according to the wind speed interval, and the WOA-LSSVM forecasting model is trained by subclass after classification to further improve the accuracy of short-term WPF. The NPKDE method is used to accurately calculate the probability density distribution characteristics of the forecasting error of wind power, and the confidence interval of the WPF is accurately calculated based on the probability density distribution characteristics. The calculation results show that the forecasting accuracy of the WOA-LSSVM model is higher than those of the LSSVM, long short-term memory (LSTM), and particle swarm optimization and least squares support vector machine (PSO-LSSVM) models, and the forecasting accuracy of the WOA-LSSVM model can be further improved after classifying the training sample set. The coverage of the confidence intervals in different time scales is higher than the corresponding confidence level, indicating that the NPKDE method can accurately describe the probability density distribution characteristics of the WPF errors.
Hybrid/Combined Darrieus–Savonius Wind Turbines: Erstwhile Development and Future Prognosis
Authors: Sarma Jyotirmoy , Jain Siddhant , Mukherjee Prasenjit , Saha Ujjwal K.
Published: March 2021

Over the last few decades, the vertical-axis wind turbines (VAWTs) have undergone intensive research mainly due to their design simplicity and independency of wind direction. The drag-based Savonius wind rotor exhibits a better starting capability, whereas the lift-based Darrieus wind rotor achieves higher efficiency over a wider operating range. Thus, in order to capitalize on their advantages, both the rotors are mounted on the same axis to form a hybrid/combined system. In this review paper, an attempt has been made to collect and analyze the past research studies in the field of hybrid wind rotors. An optimization route has also been suggested for the design of such a hybrid wind rotor to ensure that the design complexity is minimized, and at the same time, both the Savonius and the Darrieus rotors are utilized to their fullest potential. In this regard, a few important parameters are identified whose effects on the hybrid rotor performance must be investigated in future studies. Suggestions and direction of research are presented keeping in mind the improvement of the technology.
Super Aggressive S-Ducts for Air Breathing Rocket Engines
Authors: Taylor J. V. , Flanagan F. , Dunlop A. , Grimshaw S. D. , Miller R. J.
Published: March 2021

Air breathing rocket engines require turbomachinery and ducting that is substantially lighter than that used in ground-based or aerospace gas turbines. In order to reduce the weight of the axial compressor, the design of the inter-spool swan neck duct is targeted. In this paper, a circumferential splitter blade is used to reduce loading and diffusion on the duct endwalls. The splitter and duct geometry are coupled and optimized together using 2D CFD. A design is selected that is 30% shorter than ducts that are currently used in aerospace gas turbines, and the 3D flow features are investigated in further detail using an experimental rig and 3D CFD. This paper shows that the “splittered” duct has three benefits over a conventional duct design: first, separation of the endwalls is prevented even at short duct lengths, this will reduce distortion into the downstream compressor. Second, losses generated by corner separations on structural struts can be reduced by 20%, enabling short ducts to achieve high performance. Third, splittered ducts are shown to be twice as robust to uncertain inlet flow conditions as conventional ducts. This allows a designer to target high-performance short designs with reduced risk.
A Stiffness Model for Bolted Joints Considering Asperity Interactions of Rough Surface Contact
Authors: Zhou Hua , Long Xinhua , Meng Guang , Liu Xianbo
Published: March 2021

A revised fractal contact model considering asperity interactions is proposed. The displacement of the mean of asperity heights is used to represent the effects of the asperity interactions. Then, the critical contact area will be dependent on the contact load, and the contact stiffness will be an integral whose integrand is an implicit expression. The fractal dimension and the fractal roughness are obtained by the measurement of the surface profile to calculate the theoretical contact stiffness. The measurement of deformation is conducted to obtain the actual contact stiffness for verification, and the results show that the proposed model is closer to the experimental results than other models without considering asperity interactions. Once the contact stiffness is determined, a new equivalent normal stiffness model for bolted joints considering the contact of two rough surfaces is also proposed. Since the contact stiffness is dependent on the clamped force, the equivalent normal stiffness for bolted joints is calculated iteratively at given initial preload and external separating force. Different from the classical model, the equivalent normal stiffness for bolted joint decreases with the external separating force increases, and this stiffness loss will become larger with initial preload decreases. In this sense, the proposed equivalent normal stiffness model is a way to determine the suitable initial preload for different sizes of bolts when the stiffness loss is restricted to a certain range.
An Incremental Equivalent Circular Contact Model for Rough Surfaces
Authors: Wang G. F. , Liang X. M. , Yan D.
Published: March 2021

The accurate calculation of the real contact area between rough surfaces is a key issue in tribology. In this paper, based on the geometrical information of total contact area and the number of contact patches with respect to surface separation, a new method is proposed to determine the relation between real contact area and normal load. The contact of rough surfaces is treated as an accumulation of equivalent circular contacts with varying average contact radius. For a realistic range of separation, the proposed model predicts a linear relation between real contact area and load, and coincides well with direct finite element calculations. Moreover, this model is general and not confined to isotropic Gaussian surfaces.
Method for Calculating Plastic Deformation of High Resolution and Large Contact Area
Authors: Sklenak S. , Mevissen D. , Brimmers J. , Brecher C.
Published: March 2021

In a rolling contact, the tribological properties in terms of friction, wear, and fatigue are significantly influenced by the surface roughness. Due to solid contact of the surfaces in the contact area, the roughness and thus also the tribological properties change during the service life of the contact. The initial load leads to major changes of the tribological properties figured out by Brecher et al. (2019, “Influence of the Metalworking Fluid on the Micropitting Wear of Gears,” Wear, 61(434–435), p. 202996). Prediction of the initial changes in topography in the contact area is necessary for specific optimization of rolling contacts. Especially for dry rolling–sliding contact, the roughness of the surfaces is crucial for the lifetime, which is part of the investigations within the DFG priority program 2074 (357505886). In this work, an elastic-plastic contact algorithm for calculating plastic deformation for dry contact of rough surfaces with large contact area and high resolution is presented. Due to the nonlinearity behavior associated with plastic deformation, the plastic contact algorithm is based on an iterative approach. An optimized meshing strategy is implemented to calculate the elastic pressure distribution on the surface. Corresponding to the two-dimensional pressure distribution, the three-dimensional stress distribution allows the consideration of residual stresses and interactions of the microscopic peaks of the rough surface. Furthermore, the three-dimensional plastic strain distribution allows the application of an analytical approach to represent the plastic deformation of the surface. Finally, the solution of a plastic contact calculation with an exemplary topography measured on a real rough surface is presented.
Complex Modes and Solvability of Nonclassical Linear Systems
Authors: Caughey T. K. , Ma F.
Published: March 2021

The purpose of this article is to give necessary and sufficient conditions under which nonclassical linear systems can be decoupled or become solvable.
Subsmoothing: An Optimized Smoothing Method
Authors: Gutfinger Ron S. , Abraham Raj
Published: March 2021

Usually, a mesh created by an automatic mesh generator is of low quality. In order to improve the mesh quality, a smoothing algorithm is applied on the mesh. The result is a mesh ready for analysis. The smoothing is a CPU intensive iterative process. In some cases, smoothing may take longer than the initial mesh creation. In this work an optimized smoothing algorithm is presented. While iterating, the algorithm recognizes nodes that are sufficiently smoothed, and ignores them in subsequent iterations. Progressively, a smaller and smaller subset of nodes is smoothed. The result is less CPU time spent per iteration, and some decrease in the total number of iterations. This method, called subsmoothing, is applied on Laplacian smoothing of shell meshes. Examples show 30% CPU time savings and little change in mesh quality (¼%).
Process Selection for the Design of Aluminum Components
Authors: Yu Jyh-Cheng , Lotfi Sherveen , Ishii Kos , Trageser Andrew
Published: March 2021

This paper describes a method for process selection of aluminum components in the early stages of design. Aluminum has many advantages in a variety of applications in its manufacturability and recyclability. Yet, engineers who are trained to design steel components do not take full advantage of this material. The main reason is that engineers tend to be unaware of the many economical processing methods for aluminum. We have developed a program that combines preliminary screening of processes with normalized cost analysis. Design compatibility analysis (DCA) ranks each process based on its feasibility with the basic geometry, material, and production requirements. For top candidates, the program employs external cost routines for detailed comparisons. The primary processes considered are extrusion, sheet forming, forging, die casting, and sand casting. The program extends its compatibility and cost analysis to secondary operations such as bending and machining. The program should be useful for engineer training and as a preliminary design tool. The program uses HyperCard as a front-end, Prolog for logic-based analysis, and Excel for cost calculations.
Subregion Analysis by the SBSF Method in Commercial Finite Element Software
Authors: Knight Charles E.
Published: March 2021

It is difficult to analyze a large, complex structure in sufficient detail to obtain accurate results everywhere. One approach to this problem is simply to refine the whole structure model in the regions of interest which is obviously costly. Another approach is to identify a subregion of the structure and develop a separate refined model of the subregion. The most recent method for subregion analysis presented in the literature[1] is called the Specified Boundary Stiffness and Force (SBSF) method. While the method is relatively straight forward and efficient, none of the commercial code vendors has yet included an implementation.

This paper gives a brief review of the theory behind the method and then describes its application in two commercial finite element programs. Examples of the application of this method to the problem of a plate with a center hole in tensile loading are presented using ANSYS® and CAEDS(IDEAS)®. The results compare favorably to the theoretical value and show significant improvement in accuracy over the specified boundary displacement method implemented in ANSYS.

The capability of the method is also demonstrated by transfer from a 2-D global model to a 3-D subregion model in a laminated composite plate. A laminated plate with a center hole is analyzed overall by use of a layered shell element model. A subregion around the hole is then analyzed using 3-D solid elements with nodal coupling to the layered shell elements on the subregion interface. The 3-D element model provides the well-known interlaminar stresses existing at the composite edge along the hole that are not available from the shell model.
FORFMS: A FORTRAN Simulation and Analysis Model for Flexible Manufacturing Systems
Authors: Hou Chienann , Bennett Milton
Published: March 2021

The flexible manufacturing system (FMS) is designed to fill the gap between high-production transfer lines and low-production NC machines by optimized utilization of tools and machines. This paper describes a general purpose simulation and analysis model, FORFMS, for the study of flexible manufacturing system. The model is PC based and programmed in FORTRAN with fixed-increment time interval mechanism. A case study of a FMS with six workstations was conducted to evaluate the system performance and to examine control strategies.
Application of CL Formula in CAM Software for Numerical Control Machining
Authors: Shen Kang-le , Yong Pan , Xuebin Liang
Published: March 2021

CL Formula, which was originally created in China is a unified formula for crosspoints calculation and regarded as an extension of Newton-Leibniz formula. The paper discusses the features of CL formula and its applications in NC machines. The emphasis is placed in the formula’s use in CAM applications.
Pyrolysis and Oxidative Pyrolysis of Polystyrene
Authors: Gupta Ashwani K. , Keating Eugene L.
Published: March 2021

Equilibrium thermochemical calculations of polystyrene are presented here under conditions of pyrolysis and oxidative pyrolysis. Oxidative pyrolysis is examined using both air and oxygen for varying moisture content in the polystyrene. The pyrolysis of polystyrene at different temperatures prior to its oxidative pyrolysis provided significantly different results. Product gas volume and flame temperature is significantly affected by the pyrolysis temperature, nature and amount of the oxidant and the amount of moisture in the waste. Results reveal significant effect of controlled combustion on the amount and nature of the chemical species formed. The results also reveal that advanced combustion process can significantly reduce the extent of post processing of gases required, and hence the size of the equipment, for achieving environmentally acceptable thermal destruction system of the solid wastes.
Computer Aided Optimization of Mechanical Systems
Authors: Seif M. A.
Published: March 2021

Optimization is the ultimate goal of any design that aims to obtain a maximum gain out of a system at minimum expense within a framework of physical laws that restrict an absolute multi-aspect gains. The current paper presents a design methodology for optimum performance of mechanical systems. Design optimization problems have been classified based on the nature of the relation between the parameters and the restrictions imposed by virtue of operation conditions and the complexity of weighing the competitiveness of design objectives. Three classes of optimization problems are introduced: direct (explicit), interacting (implicit), and comparative (modeling). Examples of each class are given and suggested approaches to tackle the solutions are presented. These examples cover a wide range of applications in mechanical systems and would help clarify the overall framework of problem-solution schemes frequently encountered in the design of machine components.
Frequency Analysis Tools for a First Control Course Using MATLAB
Authors: Rahnamai Kourosh
Published: March 2021

A set of routines is developed using the MATLAB software package to aid students in learning methods of frequency response analysis. Routines are menu driven which would require minimum knowledge of MATLAB commands. A rapid sketch of asymptotic Bode plots is emphasized which is the basis for the lead, lag, and lead-lag compensator design techniques in the first control course taught at Western New England College.
Developing and Integrating CAE Tools in Engineering Technology
Authors: Kitto Kathleen L.
Published: March 2021

Computer Aided Engineering (CAE) Tools are being used extensively by companies in the United States to compete in an increasingly demanding global market place. Product cycle times are being reduced while quality requirements are being increased. The students enrolled in engineering and engineering technology today will be faced with competing in these competitive markets after graduation and must acquire the skills they need for that competition before graduation. In order to help make our students more competitive in that global market place, a CAE Tools course and interdisciplinary projects are being integrated into the manufacturing, plastics and electronics engineering technology programs at Western Washington University. This paper describes the new CAE Tools course at Western and decribes specific examples of interdisciplinary projects during the past academic year.
Use of 3-D Computer Graphics Simulation in a Capstone Mechanical Engineering Design Course
Authors: Alciatore David G.
Published: March 2021

This paper describes three-dimensional computer graphics simulation (CGS) and how it can be applied as a useful tool in a capstone design course in Mechanical Engineering. The necessary hardware and software to perform CGS is also outlined. Three examples of senior design projects at Colorado State University which utilized 3-D CGS to help revise and verify their designs are also presented.
A General-Purpose Software for Menu Design of CAD Projects
Authors: Pao Y. C.
Published: March 2021

A software package MenuCAD has been developed for the general need of designing menu-driven, user-friendly CAD computer programs. The main menu is formatted similar to the major contents in the final report of the design project including Contents, Analysis, Sample Design Cases, Illustrations and Tables, References, and Program Listings. Sub-menus are further divided into items delineating the steps involved in the design. Screen help messages are provided for design of the main menu and sub-menus interactively and for applying the arrow keys on the keyboard to select a sub-menus and a particular item in the sub-menu in order to execute a desired design step. MenuCAD builds the framework, its user has to supplement with a subroutine ExecItem for describing the special features and for directing how each design step should be executed in the project. A CAD design of four-bar linkage project is presented as a sample application of this package.
Fuzzy Control of Robotic Manipulators in the Presence of Joint Friction and Load Changes
Authors: Wei Li , Bo Zhang
Published: March 2021

In this paper a fuzzy robot control scheme is presented which consists of a fuzzy logic (FL) controller and a conventional derivative (D) controller. The main purpose of the paper is to study the effectiveness of membership function forms of linguistic variables on achieving desired control performance. Simulations of a two-link manipulator demonstrate that the control performance in the presence of joint friction and load changes can be improved by the scheme. The proposed scheme is quite simple in structure and can be easily implemented.
A Practical Algorithm for Shortest Paths on Polyhedral Surfaces
Authors: Rambeaud P. , Zeghloul Saïd
Published: March 2021

This paper describes a method for treating the shortest path planning problem along a convex polyhedral surface using an unfolding process. Since most planning systems use polyhedral environments, finding the shortest possible path is very useful for some typical robotics applications such as spacecraft or submersible robot motions.

The basic idea in our algorithm is to unfold the polyhedral surface into a plane, in order to convert the 3D problem to a 2D one. We provide experimental results on a box and on a sphere to illustrate the unfolding process.
Robot Obstacle Avoidance and Path Planning in Configuration Space
Authors: Toogood R. W. , Wong Chi
Published: March 2021

This paper deals with the problem of planning a collision-free path for a 3 link, revolute robot among fixed obstacles within its work environment. Both the payload and the robot links are checked for collisions with the obstacles. All path planning is performed in joint or configuration space. The first part of the paper is concerned with the visualization of the complex shape of the obstacles as they appear in joint space. The second part of the paper describes and presents results of a simple path planning algorithm.
Integrated Microcomputer-LDV Instrumentation for Studying Finite Wing Aerodynamics
Authors: Khodadoust Abdollah
Published: March 2021

The effect of a simulated glaze ice accretion on the flow field of a three-dimensional wing is studied experimentally. A PC-based data acquisition and reduction system was used with a four-beam two-color fiber-optic laser Doppler velocimeter (LDV) to map the flow field along three spanwise cuts on the model. Results of the LDV measurements on the upper surface of the finite wing model without the simulated glaze ice accretion are presented for α = 0 degrees at Reynolds number of 1.5 million. Measurements on the centerline of the clean model compared favorably with theory.
Labeled Interval Operations Involving Non-Monotonic Equations
Authors: Bains Navjoat , Ward Allen C.
Published: March 2021

The Labeled Interval Calculus (LIC) as presented in (Ward, 1989) defined three interval propagation operations for use with strictly monotonic constraint equations. This paper generalizes those propagation operations to non-monotonic constraint equations and illustrates their use by examples.
Toward Critical Thinking Mechanical Designers
Authors: Hight Timothy K. , Hornberger Lee , Sanchez Lilia A.
Published: March 2021

The Mechanical Engineering Design curriculum at Santa Clara University has been reviewed using the principles of Total Quality Management. The review has led to a clear mission statement and the inclusion of an explicit component of Critical Thinking in our curriculum. We have begun to develop the educational process that will enable us to accomplish this mission.
Coupled Lateral-Torsional Vibration of a Gear-Pair System Supported by a Squeeze Film Damper
Authors: Chen Chin-Shong , Natsiavas S. , Nelson Harold D.
Published: March 2021

This paper investigates the coupled lateral-torsional vibration of a gear-pair system supported by a cavitated squeeze film damper (SFD). Both steady state and transient dynamic characteristics of the system are analyzed. In order to gain insight into the dynamics of the system, the free vibration frequencies and modes of the linearized system are first determined. Then, the response of the nonlinear system is examined under mass unbalance and torque excitation. The trigonometric collocation method (TCM) is employed to obtain periodic steady-state responses. Direct integration is also used in order to verify TCM and capture transient response. A comparison of the steady state responses obtained with the present model by first considering only the lateral vibration and then including torsional effects demonstrates the need to include the coupling between lateral and torsional motion. Then, the effect of parameters such as gear mesh stiffness and damping, clearance-to-diameter ratio of the SFD and gear mass unbalance on the steady state response is also presented. It is found that the mass unbalance excites not only lateral-dominated modes of the coupled system but also torsional-dominated modes. Further numerical results show that the modes of the coupled system which are dominated by lateral motion can be attenuated by using a SFD, while the modes dominated by torsional motion can be substantially suppressed by gear mesh damping. Finally, the presence of multiple solutions and complex response is predicted in some frequency ranges.
Second Order Averaging Study of an Autoparametric System
Authors: Banerjee Bappaditya , Bajaj Anil K. , Davies Patricia
Published: March 2021

The autoparametric vibratory system consisting of a primary spring-mass-dashpot system coupled with a damped simple pendulum serves as an useful example of two degree-of-freedom nonlinear systems that exhibit complex dynamic behavior. It exhibits 1:2 internal resonance and amplitude modulated chaos under harmonic forcing conditions. First-order averaging studies of this system using AUTO and KAOS have yielded useful information about the amplitude dynamics of this system. Response curves of the system indicate saturation and the pitchfork bifurcation sets are found to be symmetric. The period-doubling route to chaotic solutions is observed. However questions about the range of the small parameter ε (a function of the forcing amplitude) for which the solutions are valid cannot be answered by a first-order study. Some observed dynamical behavior, like saturation, may not persist when higher-order nonlinear effects are taken into account. Second-order averaging of the system, using Mathematica (Maeder, 1991; Wolfram, 1991) is undertaken to address these questions. Loss of saturation is observed in the steady-state amplitude responses. The breaking of symmetry in the various bifurcation sets becomes apparent as a consequence of ε appearing in the averaged equations. The dynamics of the system is found to be very sensitive to damping, with extremely complicated behavior arising for low values of damping. For large ε second-order averaging predicts additional Pitchfork and Hopf bifurcation points in the single-mode response.
Random and Deterministic Vibration of a SDOF System With a Set-Up Type Stiffness Characteristics
Authors: Li Youming , Noori Mohammad , Hou Zhikun
Published: March 2021

Random vibration analysis of a nonlinear mass-spring system with a set-up spring type characteristics is considered. This system is a model of a physical device. The motion of the mass is divided into a number of stages. Using the principle of conservation of energy, governing equation of motion for various stages of displacement of the mass are derived. Deterministic free and forced vibration responses are obtained numerically. For the random vibration the excitation at the base of the system is assumed to be Gaussian white noise. Fokker-Planck-Kulmogorov equation is then used to derive the probability density function of the displacement response for this system. Several numerical results with practical engineering applications are presented.