bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Characterization of Liquid Sloshing in Containers
Authors: Karthick S. , Satish V. 
Published: January 2022

Abstract
This paper theoretically characterizes the sloshing phenomena at the free liquid surface in partially or filled stationary containers based on the analogy with surface gravity waves. The oscillations of the liquid surface and the associated dynamics of the liquid-air interface results in interfacial wave displacement of two types progressive (in-phase) and standing (out of phase) modes. This study involves a rectangular stationary fluid tank partially filled with the tested fluids and subjected to the dominant progressive wave at the liquid-air interface. The sloshing strength is decided based on the temporal progression of the generated wave spectrum obtained utilizing small-amplitude wave theory and linear stability analysis in combination. The expressions for determining the angular frequency, the phase speed, and the corresponding temporal growth rate of the progressive disturbances is derived. The tested fluids include standard liquid water and commercially preferable fluids ethylene glycol and glycerol. This model developed based on the irrotationality of fluid motion neglects the viscous influence and comprises the gravity and the surface tension mimicking a practical scenario. Utilizing deep-water assumptions, the effect of surface tension has been determined for wavenumbers in the range of 490–1250 rad/m. The independent evolution demonstrates the influence of surface tension on the temporal growth rate. Water with the maximum surface tension has a higher growth rate than a low surface tension fluid ethylene glycol among the tested fluids. The effect of surface tension is to escalate the temporal growth rate leading to instability and increased liquid sloshing rate.
Experimental and CFD Analysis of a Helical Coiled Heat Exchanger Using Various Fluids
Authors: Saiyara Shariqa , Hossain Nayeem , Ahsan Farzana , Sifat Najmus Saquib 
Published: January 2022

Abstract
Shell and Helically coiled heat exchangers enhance the heat transfer rate by increasing surface area and inducing secondary fluid flow. In this paper, the heat transfer rate and effectiveness of a shell and helically coiled heat exchanger using two fluids have been analyzed experimentally and numerically. The majority of previous studies in this regard has been on helically coiled heat exchangers with water as the working fluid. The application of helically coiled heat exchanger in cooling the tube side fluid with a coolant inside the shell has been reported in many studies. There have not been many such studies using other working fluids like water-ethylene glycol inside the tube in a coiled heat exchanger. In this work, a helically coiled tube heat exchanger has been designed and a corresponding 3D computational fluid dynamics (CFD) model has been developed. Assessment has been done on the feasibility of using ethylene glycol-water mixture as a working fluid by conducting an experimental and numerical comparison with water. Two different fluids have been used inside the helical tube, water and water-ethylene glycol (50-50). An experimental set-up has been fabricated for evaluation of thermal properties of the shell and helically coiled heat exchanger. This work analyses the behavior of parameters like heat transfer rate, pressure drop and effectiveness by introducing hot fluid through shell and cold fluid through tube under variable flow rate. Enhancement of heat transfer rate has been observed for ethylene glycol-water mixture at higher mass flow rate. The simulation data is in close agreement with the experimental data.
Crystallinity-Induced Acceleration of Intergranular Cracking in Thin-Film Interconnections Under High Current Density
Authors: Akasaki Shota , Miura Hideo 
Published: January 2022

Abstract
The degradation process of the crystallinity of grain boundaries in thin-film interconnections was visualized by applying EBSD analysis under high current density. The grain boundary diffusion was accelerated by electromigration only along random grain boundaries with low crystallinity. The crystallinity (IQ value obtained from EBSD analysis) of grain boundaries varied drastically depending on manufacturing process such as temperature, gas pressure, substrate material, and so on. The effective activation energy of self-diffusion of component element was dominated by the crystallinity of random grain boundaries. The measured value obtained from the low-crystallinity interconnections was much lower than that obtained from the thermodynamically stable bulk material, and therefore, the lifetime of intergranular cracking decreased to one hundredth in the worst case.
Inline Topology Measurement of Material Jetted Metal Parts
Authors: Rehekampff Christoph , Kirchebner Benedikt , Krebs Florian , Irlinger Franz , Lueth Tim C. 
Published: January 2022

Abstract
In Material Jetting, build material is deposited as single droplets onto a platform. This offers potential advantages such as faster processing and cheaper raw material compared to powder based processes. For metals, this technology is subject of several research projects. Due to variations in droplet size, the process inevitably results in deviations between the desired and the actual height of a printed layer. Such deviations can add up over several layers and thus lead to an unacceptably high overall geometrical deviation of the component.
One possible solution to this problem is the compensation of local height deviations by adjusting the build strategy (droplet size, droplet spacing) in the next layer. For this, it is necessary to measure the geometric deviations of the local layer heights. However, the temperatures of up to 300 °C inside the build chamber pose a challenge for the integration of a measuring system.
In this work, a process monitoring system was integrated into a previously developed printer for Material Jetting of aluminum. The system consists of an optical confocal sensor that enables contactless distance measurement. To avoid overheating of the sensor, it is located outside the build chamber. An infrared filter glass allows measurement from the outside, while heat radiation from the build platform is absorbed by the glass. The sensor is water cooled to ensure a safe operating temperature.
A calibration object and printed aluminum components were measured to validate the system. The measurement results show the potential of the system for inline process monitoring for Material Jetting. Based on this, the development of a closed-loop layer height control is now possible.
Design of a Training and Evaluation System for Surgical Robot Operation Based on Chai3d and LSTM Algorithm
Authors: Gu Chenchen , Hou Qitao , Ge Zhaojie , Teng Zhiqiang , Zhao Ping 
Published: January 2022

Abstract
Compared with traditional surgery, femtosecond laser minimally invasive surgery has many uncomparable advantages and will have a significant impact on the medical industry in the future. In this paper, a simple scene for laser minimally invasive virtual surgery training is designed, in which the testers can practice repeatedly until the basic operational requirements are met. The haptic device adopts the Geomagic Touch from American 3D Systems Company. Eight testers using Geomagic Touch handle perform four basic actions (clamping, adjusting posture, pushing / pressing, moving tiny objects) in the left interface virtual environment. Each action was performed 10 times by per tester. During the process of human-computer interaction, the position, attitude, speed, button and other information of the handle are collected in real time, and the collected data is saved in the form of text. The collected data is multivariate time series data. Based on the characteristics of multivariate time series data, this paper proposes a design of an evaluation system based on LSTM model to classify the collected data and evaluate the standard of surgical action according to the output probability of action classification.
Thermodynamic Behavior and Equation of State for Cryogenic Helium 3-4 Mixtures
Authors: Domenikos G-R. , Rogdakis E. , Koronaki I. 
Published: January 2022

Abstract
On this study the authors have derived and present an overall Equation of State for Helium 3 and Helium 4 mixtures. The point of the present study is to give equations that are usable for engineering low temperature applications such as dilution or Stirling refrigerators, without the need to make any approximations or having to use different models for different phase regions. The offered model uses all the existing data, experimental and theoretical, describing the different phases of the Helium 3-4 mixture. Additionally, to the pure data, in areas where no direct data exist the presented equations are such that they follow the expected and observed behaviors and in parallel continuously connecting the data refence points while being self-coherent and able to correlate the different thermodynamic values and their derivatives with each other. Furthermore, the effects of mixing properties in the total values have been studied and through the understanding and modeling of their behavior, combined with the equations of state for the pure isotopes the authors have been able to extend the range of the equations outside of any current models by offering a range from near absolute zero to over the lambda line of Helium 4. Because of its importance in applications also the osmotic pressure of the mixture has been included. Lastly in order to make the model more usable for thermodynamic cycles the thermodynamic maps have been created where one can directly foresee the expected behaviors without the need to run the calculations.
Design of a Modular Hand Exoskeleton for Rehabilitation and Training
Authors: Dragusanu Mihai , Iqbal Zubair , Prattichizzo Domenico , Malvezzi Monica 
Published: January 2022

Abstract
Nowadays, the rehabilitation process can significantly increase the efficacy exploiting the potentialities of robot-mediated therapies. Robot rehabilitation is an emerging and promising topic that incorporates robotics with neuroscience and rehabilitation to define new methods for supporting patients with neurological diseases. In this paper we present the design of an innovative exoskeleton for hand finger flexion/extension motion rehabilitation and training. It is designed to be modular, wearable, and easy to control and manage. It can be used by the patient in collaboration with the therapist or autonomously. The paper introduces the main steps of device design and development and presents and compare three different solutions.
Real-Time Sound Source Localization Using a Parabolic Reflector
Authors: Liu Chang , Mao Xu , Wang Chang , Heredia Juesas Juan , Martinez-Lorenzo Jose Angel 
Published: January 2022

Abstract
Contrary to the active detection methods, the passive sound source localization technologies only rely on the differences among the signals recorded by different receivers to localize the object generating the sound wave, without the knowledge of the sound source profile and excitation time. Time domain investigation methods have been widely applied in the analysis of sound source tracking, which greatly suffers from the high ambient noise problems. Instead, this paper applies an imaging method based on frequency domain cross-coherence (FDCC) operation to reconstruct the source to alleviate the effect of noise. The experimental results show the reliability of this method to recover the source in 3D. Moreover, a parabolic reflector is proposed to further increase the measurement amplitude and signal to noise ratio. The FDCC method successfully localizes the source even if the propagation path of the sound wave is disturbed by the reflector.
Synthesis-Structure-Property Relationship for Ultra-Soft Tissue-Equivalent Alginate Hydrogel
Authors: Li Xiangpeng , Gou Jihua , Ilegbusi Olusegun J. 
Published: January 2022

Abstract
Alginate hydrogels have properties that are similar to extra cellular matrix (ECM). Thus, their mechanical behavior approximates soft tissue, which makes them desirable for production of tissue-equivalent soft deformable structures. This study aims to determine the synthesis-structure-property relationship for alginate hydrogel with Young’s modulus in the range of 100∼101 kPa, equivalent to that of human lung tissue. Hydrogels are hydrophilic polymers with 3D network. Homogeneous alginate hydrogels are synthesized by direct mixture of sodium alginate and CaCO3, followed by the addition of D-glucono-δ-lactone to initiate in-situ Ca2+ release and gelation. The influence of alginate concentration and molar ratio of the constituent calcium ion to carboxyl group are evaluated while the Young’s modulus of the hydrogel is carefully controlled within the desired range. Elongation testing is performed to determine the initial-stage Young’s modulus of the material. FTIR is used to characterize the influence of synthesis parameters on the chemical bonds. Empirical relations are established between synthesis parameters and the mechanical property. The result of the study will be subsequently used to guide the additive manufacturing of soft deformable structures based on alginate hydrogels.
Experimental Investigation on Falling-Film Droplet Flow Behavior on Varied Horizontal Tube Spacing
Authors: Prudviraj K. , Deshmukh Sandip , K. Supradeepan 
Published: January 2022

Abstract
The hydrodynamic behavior of the liquid film has a great significance in horizontal tube falling-film flow. Basic flow modes between inline horizontal tubes include droplet flow, column flow, sheet flow, and intermediate flow modes such as droplet-column and column-sheet mode. The flow patterns between the tubes can be adjusted by flow rate, fluid properties, distributor type, tube spacing, and spraying width. Droplet flow is one of the fundamental flow modes, which is commonly found in industrial heat exchangers. In the present study, the complete progression of droplet flow phenomena between the inline horizontal tubes for tube spacing of 10/20/30/40 mm is visualized with the aid of high-speed photography. The Sobel edge detection algorithm with gradient function is adopted in this analysis to detect the edges. The results indicated that the droplet flow phenomena between the tubes can be broadly classified into the following phases; wavy droplet formation, droplet evolution, droplet elongation, droplet impact, and distribution of a droplet over the tubes. The development of detached spherical droplet pattern, neck formation and retraction stages were observed with increased tube spacing. For the same Reynolds number and different tube spacing, the difference in droplet impacting modes were observed. It is found that the droplet velocity increases with the increases in inter tube distance. The findings are useful for modeling a heat transfer analysis in droplets.
Thermal Expansion Simulation of Bi-Directional Taper Formation in Composite Hydrodynamic Thrust Bearings
Authors: Yasko Isaiah , Lutfullaeva Anbara , Fais Collier , Ali Muhammad , Alam Khairul 
Published: January 2022

Abstract
Tapered-land hydrodynamic thrust bearings require taper depths of approximately 20–100 μm to operate efficiently within the hydrodynamic regime. Machining the tapers in traditionally manufactured bearings increase production time and costs. The thermo-mechanical analysis presented in this work shows that the utilization of composite laminas in place of taper machining may be used to provide taper formation in hydrodynamic bearings by exploiting the thermal expansion produced from frictional heating. Thermal expansion of three different carbon/epoxy composite layups (AS-4/3501-6, IM7/3501-6, T-300/3501-6) was analyzed using ABAQUS/CAE composite module. The analysis shows that the composites provide bidirectional taper depths of 24.25 μm, 23.7 μm, and 22.27 μm while being subjected to in-service film pressures and temperatures.
Additive Manufacturing Process Parameter Optimization for Titanium-Alloy Orthopedic Implants
Authors: Gaur Bhanupratap , Ghyar Rupesh , Ravi Bhallamudi 
Published: January 2022

Abstract
Orthopedic implants are widely used for treating bone tumors and trauma defects in patients. The complex and organic geometry of patient-customized implants (PCIs) required in single order quantity makes them suitable for fabrication using additive manufacturing technologies such as Laser beam powder bed fusion. While there is considerable technical literature on these technologies, the choice of optimal process parameters to obtain the required quality considering the relevant applicable international quality standards for orthopedic implants is still a major challenge for the manufacturers.
This experimental work relies on the minimum requirements of various mechanical properties recommended by ASTM F3001-14 and ASTM F136-13 standards for determining the optimal process parameters for PCI manufacture. Ti6Al4V ELI (Titanium–6Aluminum–4Vanadium Extra-Low-Interstitial) alloy test samples were fabricated using a Direct Metal Laser Sintering (DMLS) system. The three most critical printing parameters, namely, laser power, laser velocity and hatch distance, were varied in three levels using the Taguchi approach. Properties such as ultimate tensile strength, percentage elongation and part density were considered for optimizing the process parameter combinations using VIKOR, a multi-criteria decision-making technique. The results show that a combination of moderate laser power, high laser velocity and low hatch distance values produce implants with superior mechanical properties. The proposed methodology and results are expected to help researchers and manufacturers in choosing the initial process parameters for PCI fabrication.
On the Mapping Problem in SLAM Approaches for Autonomous Robot Navigation
Authors: Raju Vomsheendhur , Selekwa Majura F. 
Published: January 2022

Abstract
Simultaneous Localization and Mapping (SLAM) is a well-known strategy for enabling robots to maneuver in unknown environments. The solution to a SLAM problem provides information about the location of the robot and the structure of the environment in a way that enables better decisions to be made by that robot. There are many ways of localizing the robot by using on-board sensors such as ranging sensors, motion sensors, and vision sensors; however, all SLAM methods tend to share features of the mapping strategy. Generally, there are two main mapping methods. One approach augments the coordinates of all landmarks in the environment with the robot pose as one state vector, and the second creates a 2-D or 3-D grid of the environment and then assigns occupancy levels of the landmarks in each grid location. Although both methods have been effective, they have some limitations. The first method is computationally burdensome since increases the size of the state vector whenever landmarks are observed; the second method treats all grid occupancy levels in binary form where all occupied grids are assumed to be at equal levels although certain grids may have occupancies that do not affect the robot mobility. This paper presents a simple but effective grid-based mapping strategy that integrates the path planning step for autonomous ground robotic vehicles. The map is presented as a 2-D surface on which each point is weighted based on observed landmarks and their sizes. This map is updated continuously as new landmarks are detected without changing memory requirements of the robot. The path planning task is implemented by joining points that are on a steep path towards the destination. Preliminary numerical results on its performance on path planning indicate the robot was able to follow the shortest path and the process is not computationally intensive.
Parametric Investigation on Thermal and Hydraulic Performance of Minichannel Heatsink
Authors: Atalay Ozan , Gultekin Murat , Cadirci Sertac 
Published: January 2022

Abstract
Insulated Gate Bipolar Transistor (IGBT) is one of the basic electronic components of rail and electric vehicle traction systems. They are used for switching and can perform this task very quickly. Regarding its operation, thermal modelling of IGBT modules is vital for obtaining temperature distribution for these components and thermal resistances of the entire IGBT as well. Nowadays, Computational Fluid Dynamics (CFD) is a robust and advantageous tool for modelling fluid flow and heat transfer problems that can be adopted to the thermal design of such critical components to better understand the effects of the design variables on the thermal-hydraulic performance of IGBT. This study is about conjugate heat transfer in a heat sink with diode and IGBT chips as heat sources and investigates the effect of minichannel porosity on Nusselt number (Nu) and the pumping power at several inlet Reynolds number (Re). The CFD analysis have been conducted parametrically and revealed that with increasing Re, both Nu and pumping powers increased significantly, indicating that heat transfer enhancement as well as power consumption are dominated by the flowrate. It is also shown that low minichannel porosities provide higher Nu and pumping power as well. The parametric studies provided a knowledge about the thermal-hydraulic performance of the IGBT and assisted to understand the effects of the governing parameters on the target functions.
Frequency Regulation With Connected Lighting Systems
Authors: Wang Peng , Brambley Michael , Poplawski Michael 
Published: January 2022

Abstract
The management of end-use energy loads, including commercial buildings, has been increasingly investigated as a promising source of services for the electric power grid. Lighting consumes about 17% of the total electricity use of U.S. commercial buildings; however, it may contribute significantly to services that improve the reliability and resilience of the grid due to its rapid speed of response. Connected lighting systems (CLS), which build upon solid-state light-emitting diode (LED) technology, can change their power demand more quickly than most other building electricity end-uses. But the potential of CLS to provide grid services has not been fully investigated. In this paper, we describe initial research to evaluate the potential of CLS for providing frequency regulation grid service. Frequency regulation is a reliability service that corrects in a matter of seconds for short-term changes in the balance between supply and demand that might affect the stability of the power system in a specific balancing area. Frequency regulation signals for a medium office building are generated from the normalized test signals for the PJM Regional Transmission Organization Reg-A and Reg-D regulations services. CLS are controlled in simulations to follow the Reg-A or Reg-D signal and thereby provide frequency regulation service. The performance of CLS providing frequency regulation is evaluated using the PJM 40-Minute Performance Score Template. The performance scores obtained for five different CLS categories responding to both Reg-A and Reg-D signals far exceed the minimum qualification score, a very promising result for CLS aiming to provide frequency regulation service.