bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time Delay-Free Nonlinear Bilateral Teleoperation With Model-Based Predictive Display
Authors: Parra-Vega Vicente 
Published: November 2021

Abstract
Robotic teleoperation is a difficult task because of the inherent difficulty to model and control time-delay nonlinear models. In order to handle tractable models, typically there have been two ways to tackle this problem: i) The first approach is to assume that the system is fast enough and thus the time delay can be neglected, in this way time-delay-free differential equations are obtained such that the controller is time-delay-free. This approach needs further formal study to validate this assumption, and so far there is neither strict nor rigorous result that support this claim, when considering the full nonlinear telerobotic dyanmics. ii) In the second approach, the time delay is considered explicitly, however typically nonlinear dynamics is neglected and then linear models are used to derive time-delay-based control systems. The second approach ignores that the robots are nonlinear systems with strong nonlinear inertial couplings, and therefore controllers based on linear time-delay models render low performance. In this paper, the teleoperation of robots is modeled, including nonlinear dynamics in the continuous domain, without any time delay, and model-based nonlinear continuous second order sliding mode controllers are proposed which guarantee finite-time convergence. Thus, this approach attempts to propose a scheme for the second approach outlined above. The teleoperation system provides force reflection to the human operator, and a kinematic-based predictive display yields visual stimuli while the master robot yields kinesthetic feedback to the operator to allow planning better desired trajectories, including contact forces, in contrast to other predictive displays that have been proposed in the literature. Therefore, the theoretical foundations of finite-time convergent telecontrol system and its advantages are discussed.
Optimized Driving Force Control of a Planar Micro-Robot Using Friction Drive Mechanism
Authors: Ferreira Antoine , Fontaine Jean-Guy 
Published: November 2021

Abstract
This paper presents a new generation of compliant piezoelectric microconveyers for microobjects based on the cooperation of arrayed direct-drive standing wave ultrasonic actuators. A method using an equivalent electromechanical circuit is proposed for estimating and analysing the optimum driving force. On the basis of the proposed method, the friction drive optimization of the micro-robot is performed through the implementation of an electromagnetic field-based preload controller. Preliminary experiments were also performed in order to demonstrate the proposed control method.
Rolling Contact Dynamics and Optimal Feedforward Control for the Modular Distributed Manipulator
Authors: Bedillion Mark , Messner William , Choset Howie 
Published: November 2021

Abstract
The Modular Distributed Manipulator System (MDMS) is an array of actuators that is capable of manipulating objects in the plane [1]. This paper derives equations of motion for the coupled dynamics of the MDMS actuators and objects riding upon it, and it derives feedforward control strategies for this multi-input, three-output system. Unlike previous work in which traction forces were generated using viscous friction caused by sliding contact between the manipulated object and the actuators, this paper considers traction forces generated by no-slip rolling contact. This approach allows more precise manipulation, because object positions and orientations and their time derivatives can be determined by wheel encoder information. The dynamic equations account for the electromechanical dynamics of each actuator and the coupling between them and the translational and rotational dynamics of the manipulated object. This paper then presents two different feedforward control strategies based on minimizing the sum of the squares of the inputs or minimizing the total system power.
Visualization and Computation of the Flow of a Highly Shear-Thinning Liquid Past the Axisymmetric Contraction-Expansion: Application to Blood Flow Through Stenotic Vessels
Authors: Quintella Erick F. , Mendes Paulo R. Souza , Azevedo Luis F. A. , Naccache Mônica F. 
Published: November 2021

Abstract
Stenosis is a constriction or narrowing of a duct or passage. This word is often used to refer to constrictions that occur in blood vessels, especially arteries. A stenotic vessel generally causes blood flow stagnation and hence formation of thrombus, which may be rather harmful to the human physiology. In this work we perform flow visualization experiments and finite-volume computation to study the flow of an yield-stress (or highly shear-thinning) liquid through a tube in the neighborhood of an axisymmetric constriction. The rheology of the liquid was chosen to be close to the one of blood with 55% hematocrit Reynolds and Yield number values characteristic to different arteries have been studied, as well as different levels of constriction. Results for a Newtonian liquid were also obtained, for comparison purposes. Numerical solutions of the mass and momentum balance equations were obtained. In these solutions it was assumed that the materials behave like a Generalized Newtonian Liquid with a biviscosity function, which mimics closely the Herschel-Bulkley equation but allows deformation below the yield stress limit.
Among other findings, it has been observed that the non-Newtonian rheology causes a significant change in the flow pattern in the neighborhood of the stenosis. Because the conditions for thrombus formation are directly related to the flow pattern, studies of the flow through stenotic vessels that assume a Newtonian rheology may lead to erroneous conclusions.
A Study of the NOx Emission in a Regenerative Industrial Furnace
Authors: Jiang Qing , Zhang Chao 
Published: November 2021

Abstract
A study of the nitrogen oxides (NOx) emission and combustion process in a gas-fired regenerative, high temperature, low emission industrial furnace has been carried out numerically. The effect of two additives, methanol (CH3OH) and hydrogen peroxide (H2O2), to fuel on the NOx emission has been studied. A moment closure method with the assumed β probability density function (PDF) for mixture fraction is used in the present work to model the turbulent non-premixed combustion process in the furnace. The combustion model is based on the assumption of instantaneous full chemical equilibrium. The results showed that CH3OH is effective in the reduction of NOx in a regenerative industrial furnace. However, H2O2 has no significant effect on the NOx emission.
Effects of Initial Diameter on Burning of Nonane Droplets in a Non-Buoyant and Buoyant Ambience: Burning Rate, Soot Formation and Flame Structure
Authors: Bae J. H. , Avedisian C. T. 
Published: November 2021

Abstract
The results from nonane droplet combustion experiments conducted at 1g and μg are analyzed and compared in the following aspects: the burning rate, soot formation, flame structure. By varying the initial droplet diameter, we observe and discuss the effect of Do on droplet burning. The μg experiments were performed in a drop tower and a drag shield was used to create a low buoyant environment All experiments were fiber-supported and used the same experimental instruments. The droplet size between 0.40 to 0.95mm was examined in the experiments.
Results showed that droplet burning is nonlinear in both a buoyant and a non-buoyant environment for the initial droplet diameters examined. Soot formation, which is influenced by Do may strongly affect the droplet burning process in both environments. The large droplet produces more soot and bums slowly whereas the small droplet bums fast because there is less soot.
Using Amorphous Material Properties in Scattering-Mediated Acoustic Mismatch Model for Predicting Thermal Boundary Resistance
Authors: Devpura Amit , Prasher Ravi S. , Phelan Patrick 
Published: November 2021

Abstract
Solid-solid thermal boundary resistance (Rb) plays an important role in determining the heat flow between materials. The acoustic mismatch model (AMM) and the diffuse mismatch model (DMM), work pretty well in describing and predicting the thermal energy transport at solid-solid interface at very low temperatures (in the range of few Kelvin). At moderate cryogenic temperatures they do not perform that well, and the reason may be attributed to the dominance of scattering in determining Rb. Scattering mediated acoustic mismatch model (SMAMM) was developed on this principle. Though SMAMM works well, it has some fundamental problems. SMAMM’s assumption of U-processes, for amorphous layer formed between materials, is physically unexplainable. It also assumes unrealistically small scattering time. We propose a modified version of SMAMM called Amorphous SMAMM, which takes into account amorphous material properties for the interstitial layer formed, to find the scattering time to be used in SMAMM. This model performs better than all the models in the range of 25 to 60 K in predicting Rb. Above this temperature, original SMAMM performs better, but Amorphous SMAMM always performs better than the AMM. Amorphous SMAMM does not run into any physical problems with the assumptions made, hence the results have a better physical significance than SMAMM’s.
Comparison Between Thermal Conductive Models for Moving Heat Sources in Material Processing
Authors: Bianco Nicola , Manca Oronzio , Nardini Sergio 
Published: November 2021

Abstract
A comparison between two quasi-steady state models describing a three dimensional conductive thermal field inside a brick-type solid under a moving laser heat source with a Gaussian profile is carried out. One of the two model has been simplified by neglecting the thermal diffusion along the direction of the motion. This model is suitable for high values of the Peclet number. The thermophysical properties of the solid are temperature dependent and radiative and convective heat losses, the latter due to an impinging gas jet on the upper surface, have been taken into account. The comparison has been made in terms of temperature profiles, maximum temperature ratios and temperature fields. The differences between the two models are around 35% for Reynolds numbers greater than 10000 and for Pe = 0.1. The influence of the width of the solid is weak for Reynolds number greater than 10000. Relative errors are less than 5% for Pe ≥ 1 and they are negligible for Pe ≥ 5 for all the parameter ranges considered in this paper.
Predictions of Carbon Fluxes During a Low Pressure Carburizing Treatment
Authors: Jacquet Philippe , Rousse Daniel R. , Ibarra Clemente C. 
Published: November 2021

Abstract
This paper presents the qualitative assessment of a novel device developed for the regulation of carburizing processes in industrial vacuum furnaces. The proposed device involves a U-shaped thin wall iron tube: the outside surface of the tube is exposed to the carburizing atmosphere simultaneously with the workload, while the decarburizing gas mixture (here H2 + H2O) is circulated inside the tube. The outflow of decarburizing mixture is then continuously analyzed and eventually permits to determine the carbon potential and the transfer coefficient at the interface between the carburizing atmosphere and the workloads. To assess the principle, the probe has been used to compare the carburizing powers of different gases (propane, methane, ethylene, and acetylene) for a specific set of parameters. The results reported here, compared with microhardness and micrographies of the samples, indicate that the probe can indeed be used to carry out this task.
On the Design of Continuum Thermal Transport Systems With Applications to Solidification Processes
Authors: Zabaras Nicholas J. 
Published: November 2021

Abstract
A general class of design problems is examined in thermal transport systems. We mainly address inverse problems with overspecified coupled boundary conditions in one part of the boundary and unknown thermal conditions in another part of the boundary. The methods of choice for the solution of the above inverse problems are functional optimization methods using appropriately defined continuum sensitivity and adjoint problems. Conjugate gradient techniques, preconditioning and regularization are considered within an innovative object-oriented finite element framework.
Our particular interest for examining such inverse transport systems arises from the desire to address the design of directional solidification processes that lead to desired microstructures. As the main application of this paper, we will address the calculation of the mold/furnace heat flux conditions such that a desired solidification state (growth rate and temperature gradient) is achieved at the freezing interface. Changes in growth rate and thermal gradient at the freezing interface are known to alter the relative importance of thermal/mass transport and interfacial energy effects, and the magnitude of this partitioning of available driving forces dictates the formation of specific microstructures.
Intensity and Uniformity of Gallium Nitride Deposition in Sublimation Sandwich Growth
Authors: Wu B. , Zhang H. 
Published: November 2021

Abstract
Gallium Nitride (GaN) bulk crystal growth is a challenging process due to its high melting temperature, low sublimation/decomposition temperature, very high equilibrium nitrogen vapor pressure, and low solubility. A GaN bulk crystal can be grown from the vapor phase by either evaporation of the gallium (Ga) metal or sublimation of GaN powder in an ammonia (NH3) atmosphere in a temperature-controlled growth furnace. The Sublimation Sandwich Technique (SST) is one of the techniques which utilizes reaction of gallium vapors with ammonia. Not only a high growth rate (up to 1mm/h) but also the intensity and uniformity of the deposition can be achieved and controlled through changing temperatures on the source, and the substrate, and the distance between them. A GaN growth model using SST has been developed to investigate the effects of the incoming velocity, source temperature, temperature difference, and the gap width on the growth cell during the growth process.
Characterization of Ceramic Components Exposed in Industrial Gas Turbines
Authors: Ferber M. K. , Lin H.-T. 
Published: November 2021

Abstract
This paper provides a review of recent studies undertaken to examine the mechanical and thermal stability of silicon nitride ceramic components that are currently being considered for use in gas turbine applications. Specific components examined included a bowed ceramic nozzle evaluated in an engine test stand, ceramic vanes exposed in two field tests, and an air-cooled vane that is currently under development. Scanning electron microscopy was used to elucidate the changes in the microstructures arising from the environmental effects. The recession of the airfoils resulting from the volatilization of the normally protective silica layer was also measured. The stability of the intergranular phases was evaluated using x-ray diffraction. The surface strength was measured using a miniature biaxial test specimen, which was prepared by diamond core drilling.
Investigation and Analysis of Structural Cracking in Transit Car Trucks
Authors: Janiszewski John A. , Chrismer Steven M. , Pearson John B. 
Published: November 2021

Abstract
This paper describes an investigation into the causes of cracking of transit car truck side frames on the PATCO system. The investigation included inspection of the PATCO fleet, laboratory examination of a sample from a failed truck, field-testing of an instrumented truck, measurement of residual stresses in the truck, and engineering analysis of the resulting data. It was concluded that the observed cracks were slowly propagating due to fatigue from low-level stresses induced by lateral and vertical loading from routine curving forces and other vehicle-track interactions. The side frames with fatigue cracks can be repaired by welding without the need for postweld stress relief and the lifetime of those that do not have cracks at present can be extended by preventive measures. The combination of preventive measures and repairs should enable the trucks to serve for the balance of the PATCO fleet lifetime without the need to purchase replacement trucks. Continued surveillance of the trucks in the area of concern will be necessary.
Cerebral Amyloid Angiopathy Is Associated With Emotional Dysregulation, Impulse Dyscontrol, and Apathy
Authors: Smith Eric E. , Crites Stephanie , Wang Meng , Charlton Anna , Zwiers Angela , Sekhon Ramnik , Sajobi Tolulope , Camicioli Richard , McCreary Cheryl R. , Frayne Richard , Ismail Zahinoor 
Published: November 2021

Background
Cerebral amyloid angiopathy (CAA) causes cognitive decline, but it is not known whether it is associated with neuropsychiatric symptoms (NPS).

Methods and Results
Participants with CAA, mild cognitive impairment, mild dementia due to Alzheimer's disease, and normal cognition were recruited from stroke and dementia clinics and community advertising. NPS were captured using the Neuropsychiatric Inventory Questionnaire short form. The number and total severity (number multiplied by severity of each symptom [mild, moderate, or severe]) of NPS were analyzed using generalized linear regression with a negative binomial link and multiple linear regression, adjusting for age, sex, and education. A total of 109 participants (43 with CAA, 15 with Alzheimer's disease, 28 with mild cognitive impairment, and 23 with normal cognition) (mean age 71.1 [SD=7.6]; 53.2% male) were included. The most frequent NPS in CAA were depression/dysphoria (48.8%), irritability/lability (37.2%), agitation/aggression (37.2%), apathy/indifference (34.9%), and anxiety (32.6%). In adjusted models, patients with CAA had 3.2 times (95% CI, 1.7–6.0) more NPS symptoms and 3.1 units (95% CI, 1.0–5.1) higher expected severity score. The number of NPS was similar to patients with mild cognitive impairment (3.2 times higher than controls) but less than in patients with Alzheimer's disease dementia (4.1 times higher than controls). Within patients with CAA, there were 1.20 times (95% CI, 1.01–1.32) more NPS per 1% increase in white matter hyperintensity as a percentage of intracranial volume.

Conclusions
NPS are common in CAA, with a similar prevalence as in mild cognitive impairment. The association of the total number of NPS with higher white matter hyperintensity volume suggests that white matter damage may underlie some of these symptoms.
Predictors and occurrence of antenatal depressive symptoms in Galle, Sri Lanka: a mixed-methods cross-sectional study
Authors: Wyatt Sage , Ostbye Truls , De Silva Vijitha , Lakmali Prabodha , Long Qian 
Published: November 2021

Abstract
Background
There is a high prevalence of antenatal depression in low-or-middle-income countries, but information about risk factors in these settings is still lacking. The purpose of this study is to measure the prevalence of and explore risk factors associated with antenatal depressive symptoms in Galle, Sri Lanka.

Methods
This study used a mixed-method approach. The quantitative portion included 505 pregnant women from Galle, Sri Lanka, with health record data, responses to psychometric questionnaires (MSPSS and PRAQ-R2), and antenatal depression screening (EPDS). The qualitative portion included interviews with public health midwives about their experiences and routine clinical practices with women with antenatal depressive symptoms.

Results
Prevalence of antenatal depressive symptoms was 7.5%, highest in women over the age of 30 (13.0%, OR = 3.88, 95%CI = 1.71 – 9.97), with diabetes (21.9%, OR = 3.99, 95%CI = 1.50 – 9.56), or pre-eclampsia in a previous pregnancy (19.4%, OR = 3.32, 95%CI = 1.17 – 8.21). Lower prevalence was observed in the primiparous (3.3%, OR = 0.29, 95%CI = 0.12 – 0.64) employed outside the home (3.6%, OR = 0.33, 95%CI = 0.13 – 0.72), or upper-middle class (2.3%, OR = 0.17, 95%CI = 0.04 – 0.56). Anxiety levels were elevated in depressed women (OR = 1.13, 95%CI = 1.07 – 1.20), while perceived social support was lower (OR = 0.91, 95%CI = 0.89 – 0.93). After multivariable adjustment, only parity (OR = 0.20, 95%CI 0.05 – 0.74) and social support from a “special person” (OR = 0.94, 95%CI = 0.77 – 0.95) remained significantly associated with depressive symptoms. Qualitative findings also identified antenatal health problems and poor social support as risk factors for depressive symptoms. They also identified different contributing factors to poor mental health based on ethnicity, higher stress levels among women working outside the home, and misinformation about health conditions as a cause of poor mental health.

Conclusions
Prevalence of antenatal depressive symptoms in Galle is lower than the recorded prevalence in other regions of Sri Lanka. Risk factors for antenatal depressive symptoms were identified on biological, psychological, and social axes. These variables should be considered when developing future guidelines for mental health and obstetric treatment in this context.
Prognostic value of immune factors in the tumor microenvironment of patients with pancreatic ductal adenocarcinoma
Authors: Kiryu Sachie , Ito Zensho , Suka Machi , Bito Tsuuse , Kan Shin , Uchiyama Kan , Saruta Masayuki , Hata Taigo , Takano Yuki , Fujioka Shuichi , Misawa Takeyuki , Yamauchi Takashi , Yanagisawa Hiroyuki , Sato Nobuhiro , Ohkusa Toshifumi , Sugiyama Haruo , Koido Shigeo 
Published: November 2021

Abstract
Background
Both activated tumor-infiltrating lymphocytes (TILs) and immune-suppressive cells, such as regulatory T cells (Tregs), in the tumor microenvironment (TME) play an important role in the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC).

Methods
The densities of TILs, programmed death receptor 1 (PD-1) + T cells, and forkhead box P3 (Foxp3) + T cells were analyzed by immunohistochemical staining. The associations of the immunological status of the PDAC microenvironment with overall survival (OS) time and disease-free survival (DFS) time were evaluated.

Results
PDAC patients with a high density of TILs in the TME or PD-1-positive T cells in tertiary lymphoid aggregates (TLAs) demonstrated a significantly better prognosis than those with a low density of TILs or PD-1-negativity, respectively. Moreover, PDAC patients with high levels of Foxp3-expressing T cells showed a worse prognosis than those with low levels of Foxp3-expressing T cells. Importantly, even with a high density of the TILs in TME or PD-1-positive T cells in TLAs, PDAC patients with high levels of Foxp3-expressing T cells showed a worse prognosis than patients with low levels of Foxp3-expressing T cells. A PDAC TME with a high density of TILs/high PD-1 positivity/low Foxp3 expression was an independent predictive marker associated with superior prognosis.

Conclusion
Combined assessment of TILs, PD-1+ cells, and Foxp3+ T cells in the TME may predict the prognosis of PDAC patients following surgical resection.