bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Numerical Study of Sand Particle Erosion in a Series of Ball Seats in Gas-Particle Two-Phase Flow
Authors: Rasteh A. , Farokhipour A. , Rasoulian M. A. , Mansoori Z. , Saffar-Avval M. , Ahmadi G. , Mofakham A. A. 
Published: November 2019

Abstract
Fracking (fracturing) is of great importance for enhancing oil and gas production from low permeability reservoirs. Since in fracking fluid, suspension of sand particles are used, the erosion failure of fracturing equipment has become an increasing concern. Accordingly, investigation of erosion of commonly used fittings such as ball seats in order to decrease its adverse consequences has attracted considerable attentions. Although the erosion wear of gas-solid flows in the pipe sudden expansion was investigated in the literature, the effect of particle size, ball seat shape and the contraction configurations on the erosion-induced wear is not fully understood. This study is aimed to explore the most erosion-resistant configuration of a ball seat under various operational conditions. A CFD model is used and a wide range of geometries are investigated. The studied configurations are categorized in three main groups including single cone, double cone and curved cone. In each category, different cone angles and curve styles are considered.
The results showed that, among the single cone ball seats, the cone angle of 15° is the most erosion-resistant configuration. It was also shown that the third-order curve style cone has the best erosion performance.
Flow Characterization of Microfluidic Paper-Based Analytical Devices With Hollow Channels
Authors: Zhang Haipeng , Barmore Danielle , Ryu Sangjin 
Published: November 2019

Abstract
Microfluidic paper-based analytical devices (μPADs) are cost-effective point-of-care diagnostic devices. μPADs consist of porous filter paper patterned with hydrophobic solid ink barriers to create flow channels. Because a liquid sample flows through the paper channel driven by capillary force, the resultant flow is usually slow. To overcome this limitation, a hollow channel can be added to a μPAD to increase the flow speed significantly. The liquid flow through the hollow channel is known to be driven by a pressure difference between the inlet and outlet of the device. Accordingly, theoretical models have been proposed to understand and predict flow characteristics of μPADs with hollow channels. The goal of this study is to experimentally characterize liquid flow through μPADs having a hollow channel, by investigating relationships among the travel distance of the liquid front through the μPADs, the applied pressure difference, and the dimension of the hollow channel. Thus, the outcome of this study would contribute to validating the theoretical models and enable better control of liquid sample flow in μPADs with hollow channels.
Locomotive Capabilities of a Free-Swimming Robotic Tuna
Authors: Noviasky Nicholas , Matta Alexander , Bayandor Javid 
Published: November 2019

Abstract
As we try and understand more about the oceans and the creatures that inhabit them, the need for effective modes of aquatic transportation becomes abundantly clear. Taking a step back from traditional propeller-based systems, we look toward nature and the millions of years of natural selection to find inspiration. The successful designs that have prospered vary greatly from creature to creature depending on their lifestyle. From rays to jellyfish, the propulsion methods used are tailored for a specific purpose. Considering the vastness of the oceans and our desire to explore them, a quick and efficient mode of locomotion would be well suited for this task. A great example of this type of swimmer can be found within the genus Thunnus.
Tuna rely on a lift-based propulsion system classified as thunniform swimming. The majority of thrust from this propulsion method is derived from the caudal fin and part of the tail. As the tail sweeps through the water, interesting vortex structures are shed from the trailing edge of the lunate fin. Along with velocity components that travel parallel to the movement of the fish, two separate vortices are shed from the top and bottom inner surfaces of the caudal fin and meet at the lengthwise center axis of the fish. These can be best visualized from the flow velocity components analyzed within a plane just behind the caudal fin and perpendicular to the body length axis. Over time, a reverse Karman vortex street is formed from the combination of vortices from multiple tail beats. A robotic tuna and CFD model were created with the minimum number of joints to approximate thunniform swimming.
A modified scotch yoke mechanism was used to convert uniform rotation of a brushless DC motor to oscillatory motion that mimics the tail of a tuna. A servo is mounted on the tail to provide an adjustable angle of attack for the caudal fin. The dynamic CFD model of the tuna employs overset meshing techniques created in ICEM CFD 18.2 and is simulated within ANSYS Fluent 18.2. The model is actuated at the start of the tail and the base of the fin to represent thunniform swimming. The body of the tuna is held static as steady flow is passed around the model. The flow velocity was chosen as an approximation of the speed of a tuna of comparable size and tail-beat frequency.
Neutron Imaging of Capillary Effect Under High-Pressure and High Temperature Condition
Authors: Susanto Wilson , Ihara Tomonori , Hazuku Tatsuya , Morooka Shinichi , Ito Daisuke 
Published: November 2019

Abstract
The supercritical water reactor (SCWR), which is one of the generation IV reactor concepts, has particular thermal hydraulics features. If a severe accident happens and pressure and mass flux in a reactor core are rapidly decreased, a film boiling on a fuel cladding tube surface may occur at subcritical conditions. Once the film boiling happens, heat transfer on the cladding tube surface drastically deteriorated and may result in serious damage to the reactor core. The cooling capability during the film boiling depends on the wetting phenomenon, therefore, experiments to clarify wettability phenomenon in subcritical condition are required.
One of the experiments to clarify the wettability phenomenon is the capillary action experiment. In the closed system, the water level will elevate due to the injection of the water. The difference in water elevation is due to the capillary force in the different diameter of the pipes. Based on the different water levels with known surface tension, it is possible to quantify the contact angle. The challenge of the experiment is to measure the precise elevation of the water in small diameter metal pipes under high-temperature and high-pressure condition. Therefore, the neutron imaging was applied in this experiment. Neutron imaging is a structure visualization technique. The principle is the neutron flux captured after passing through the object for visualizing the structure of an object. Neutron flux which is captured using a scintillator plate thus can be seen as an image using CCD video camera.
Our research group focuses on the radiation induced surface activation (RISA) effect. Significant improvements of surface wettability and boiling heat transfer on oxide film coatedmaterials by the RISA were confirmed especially under room temperature conditions. In this present research, we evaluate the RISA effect on capillary action in a subcritical condition using the various diameter of the pipe. Neutron imaging was used to visualize the water-gas interface in small diameter stainless steel pipes. The capillary pipes with various inside diameters such as 0.5, 0.8, 1.2, 1.4, and 1.8 mm were used as a test section which was heated up to a temperature of 320° C under a pressure of 21 MPa. The pipes irradiated by γ-ray with an integrated irradiation dose of approximately 500 kGy and non-irradiated pipes with various diameters are installed in parallel and water levels in each pipe were compared to evaluate capillary action differences.
Design and Verification of Cooling Fans for Engine Rooms of Mobile Hydraulics Vehicles
Authors: Kim J.-H. , Lee G.-P. , Lim C.-H. , Lee S. 
Published: November 2019

Abstract
To provide an engine room of mobile hydraulic vehicle with an effective cooling for the combination set of a radiator, a charge air cooler, and an oil cooler, a 500mm-diameter, axial fan is designed to have a 8,800 m3/hr at a resistance of 20mm Aq static pressure with a sound power level less than 86 LwA. The design parameters of sweep angle amplitude, wavelength of sweep angle change, airfoil type, and stagger angle are examined in terms of fan performance and its sound power generation. The surface curvatures generated by the sinusoidal sweep angle variation in the radial direction are proved to result in quite different flow patterns, thereby different types of specific sound power characteristics at the same flowrate. The acoustic noise sources are examined and discussed by using an acoustic imaging technique.
Computational Evaluation of Stability in Slosh Dynamics of Tank Vehicles Using Zero Moment Point
Authors: Usman M. , Sajid M. 
Published: November 2019

Abstract
Sloshing characterized by inertial waves has an adverse effect on the directional dynamics and safety of partially filled tank vehicles, limiting their stability and controllability during steering, accelerating or braking maneuvers. A mathematical description of the transient fluid slosh in a horizontal cylindrical tank should consider the simultaneous lateral, vertical and roll excitations assuming potential flows and a linearized free-surface boundary condition. While the determination of vehicle stability would require coupling this model to a dynamic roll plane model of a tank vehicle resulting in a computationally expensive analysis. Considering the need for a simpler method to predict roll stability for partially filled tank vehicles, we explore the Zero Moment Point of a liquid domain as a novel solution to this challenge. Numerical investigations are carried out in a three-dimensional partially filled tanks while tracking the movement of the liquid-air interface by employing the volume of fluid method in OpenFOAM. The center of Mass and Zero Moment Point were calculated from the computational results using analytical expressions. The movement of free surface is found to be in good agreement with available literature. The center of mass of the liquid domain was traced as a practical means to quantify the slosh in the tanker. The analyses are performed for different fluid fill heights at varying speeds. The results suggest that the roll stability of tank vehicles can be efficiently analyzed using the zero moment point with significantly lower computational effort.
An Optical Method for Measuring Water Wave Profiles
Authors: Dan Kazuhide 
Published: November 2019

Abstract
When sunlight waves travel into the interface between water and air sunlight waves refract at this interface and produce the fringe pattern in brightness or the light intensity profiles on the sandy bottom in coast. These fringe patterns related to wave profiles are experimentally recorded at the observation board below the transparent glass test channel using an artificial light inside a laboratory. It is possible to calculate the wave profile by applying Suzuki-Sumino method to this fringe pattern in experiment by recording a video closely in front of the inspection area and by using a plano convex lens in order to produce parallel waves. The purpose of this research is to show an optical method to measure gravity wave profiles in experiment. In this paper the modified method is shown to measure the wave profile correctly to collaborate an optical method using a plano convex lens and a calibration method using a capacitance-type wave meter.
Requirements Culture: A Case Study on Product Development and Requirement Perspectives
Authors: Elena Maria Vittoria , Wentzky Chase , Summers Joshua D. 
Published: November 2019

Abstract
A desire to better understand requirements and their uses within product development inspired this case study conducted at a large power tool company. Researchers were interested in determining if a requirements culture existed within the company investigated, how this culture varied across departments, and how individuals at the company viewed requirements in engineering design. Ten semi-structured interviews were conducted by five teams of interviewers over the course of two months to answer these questions. Employees in various positions across the company were interviewed in the study including Project Engineers, a CAD Designer, an Industrial Designer, Project Managers, and Vice Presidents. Through a detailed analysis of the interview transcripts and documentation, it was determined that the company did have a definite requirement culture and that the transfer of requirements across departments must remain consistent for the individual groups to be effective. Furthermore, it was found that employee engagement with requirements was more significant with those who were involved in the early stages of product development.
Simultaneous Resonance and Anti-Resonance in Dynamical Systems Under Asynchronous Parametric Excitation
Authors: Karev Artem , Hagedorn Peter 
Published: November 2019

Abstract
Since the discovery of parametric anti-resonance, parametric excitation has also become more prominent for its stabilizing properties. While resonance and anti-resonance are mostly studied individually, there are systems where both effects appear simultaneously at each combination resonance frequency. With a steep transition between them and a high sensitivity of their relative positions, there is a need for a concurrent study of resonance and anti-resonance. The semi-analytical method of normal forms is used to derive approximate analytical expressions describing the magnitude of the stability impact as well as the precise locations of stabilized and destabilized areas. The results reveal that the separate appearance of resonance and anti-resonance is only a special case with synchronous parametric excitation. In particular, in circulatory systems the simultaneous appearance is expected to be much more common.
The Effect of Starvation on a Thermal Mixed EHL Line Contact
Authors: Li Sheng , Masse Danielle 
Published: November 2019

Abstract
To investigate the effect of the inlet starvation severity on the flash temperature, which dictates the scuffing failure, a thermal mixed elastohydrodynamic lubrication model is developed for line contacts operating under the starved lubrication condition. The scuffing failure of high speed gearing applications is commonly associated with the very high sliding condition occurring in the vicinity of either the root or the tip, where the shear thinning effect that decreases the lubrication film thickness and increases the contact pressure is significant. Utilizing a generalized Newtonian Reynolds equation, the lubricant viscosity dependence on the shear rate, as well as on the pressure and temperature, is incorporated for the proper and accurate modeling of the tribological behavior under the high sliding condition. A film fraction parameter is employed in the Reynolds equation to include the starvation and cavitation description, eliminating the need for the measured or assumed meniscus location in the inlet zone. Considering different operating and surface roughness conditions, a parametric study is performed to show an asymptotic relationship between the flash temperature and the inlet starvation severity.
Geometric Simulation for Thick Origami
Authors: Kwok Tsz-Ho 
Published: November 2019

Abstract
Origami is an art that creates a three-dimensional (3D) shape only by folding. This capability has drawn much research attention recently, and its applied or inspired designs are utilized in various engineering applications. Most current designs are based on the existing origami patterns and their known deformation, but origami patterns are universally designed for zero-thickness like a paper. To extend the designs for engineering applications, simulation of origami is needed to help designers explore and understand the designs, and the simulation must take the material thickness into account. With the observation that origami is mainly a geometry design problem, this paper develops a geometric simulation for thick origami, similar to a pseudo-physics approach. The actuation, constraints, and mountain/valley assignments of origami are also incorporated in the geometric formulation. Experimental results show that the proposed method is efficient and accurate. It can simulate successfully the bistable property of a waterbomb base, two different action origami, and the elasticity of origami panels when they are not rigid.
A Novel Hybrid Modeling Method for Contact Problems
Authors: Liu Qian , Li Haiquan , Ma Ou 
Published: November 2019

Abstract
Accurately modeling of many practical contact scenarios such as robotic grasping and assembly is a challenging problem because of complex contact geometry and surface uncertainties. This paper presents a new hybrid contact model (HCM), which combines a traditional physical model and a data-driven model to make a more accurate description of a contact dynamics phenomenon. When a physical model is employed to describe a complex contact case, it usually has error from an experimental data measured from the contact case to be modeled because of inevitable unmodeled and/or unknown factors. The data-driven model is used to represent this error, which is an artificial neural network model trained from experimental data using a machine learning technique. A bouncing ball example is presented to demonstrate the feasibility of the presented approach.
Vibrations of a Double Beam Structure Carrying a High-Pressure Driven Projectile
Authors: Khair Alexander , Yang Bingen 
Published: November 2019

Abstract
In this paper, a mathematical model of a double beam structure carrying a high-pressure driven projectile is developed for investigation of the physical behaviors of gun barrels during firing. The dynamic response of such a weapon system is particularly interesting when reduction of muzzle vibrations and relevant dynamic stress in the structure is needed to improve the life cycle of the gun. In the model presented, the Timoshenko beam theory is implemented, and realistic characteristics of the physical system are considered. Numerical simulation results are presented for the displacement and rotation of the two beams, and the rigid-body projectile mass.
An Improved Model for Calculating the Mesh Stiffness of Helical Gears
Authors: Wei Jing , Hou Shaoshuai , Zhang Aiqiang , Zhang Chunpeng 
Published: November 2019

Abstract
Time-varying mesh stiffness (TVMS) is one of the important internal excitations of gear transmission systems. Accurate solution of meshing stiffness is the key to research the vibration response of gear transmission system. In the traditional analytical method (TAM), the TVMS of single-teeth engaged region consist of bending, shearing, axial compression deformation stiffness, fillet-foundation stiffness, and Hertzian contact stiffness, the TVMS of double-tooth engaged region is the sum of the single-tooth engaged region, which will lead to repeated calculation of the fillet-foundation stiffness. In order to overcome this shortcoming, considering the coupling effect between two pairs of meshing tooth, an improved method of fillet-foundation is adopted to calculate to TVMS of each slice gear. According to the ‘slicing method’, the helical gear is divided into slice gear. Considering the coupling effect of each slice gear, the TVMS of helical gear can be obtained. The improved analytical method (IAM) is verified by comparing with finite element method (FEM) and TAM. Based on the IAM, the effects of the helical angle, face width, the number of gear, and modification coefficient on the mesh characteristics are analyzed. The results show that the IAM is consistent with the FEM and also consistent with TAM in single-tooth engagement. However, there is obviously error with the TAM in double-tooth or multi-tooth engagement.
Research on Prediction Method of Transmission Accuracy of Harmonic Drive
Authors: Hu Qiushi , Liu Zhifeng , Cai Ligang , Yang Congbin , Zhang Tao , Wang Guang 
Published: November 2019

Abstract
Harmonic drive is an indispensable device for robotic joint, and transmission accuracy of harmonic drive is one of its most important performance indexes. Due to the unsystematic research on the accuracy of harmonic drive, the accuracy consistency of harmonic drive is poor, and the prediction accuracy is seriously insufficient. This study focuses on modeling of transmission error system and prediction of transmission accuracy. Through tracing analysis of transmission error of harmonic drive, a transmission error model including manufacturing, assembly and tooth profile error is established. Based on Rayleigh distribution of error sources and considering multi-tooth meshing effect of harmonic drive, the transmission accuracy prediction model is built. Tooth profile error is measured by gear measuring center, dimension error and geometric tolerance are gauged by coordinate measuring machine. The transmission accuracy of three types harmonic drive (SHG14, SHG20 and SHG25) is measured by harmonic transmission error test bench under rated conditions. The comparison results show that the difference between the predicted and experimental values is less than 15%, which proves the validity of the accuracy prediction model. Prediction method play a crucial role for accuracy control of harmonic drive system.
Dynamical Modelling and Control of Snake-Like Motion in Vertical Plane for Locomotion in Unstructured Environments
Authors: Javaheri Koopaee Mohammadali , Pretty Christopher , Classens Koen , Chen XiaoQi 
Published: November 2019

Abstract
This paper introduces the equations of motion of modular 2D snake robots in the vertical plane. In particular, the kinematics of pedal wave motion (undulation in vertical plane) of modular snake robots is presented and using the Euler-Lagrange method, the equations of motion of the robot are obtained. Moreover, using the well-known Spring-Damper contact model, external contact forces are taken into account and pedal wave locomotion on uneven terrain is modelled and simulated. Enabled by the dynamical model of the robot, an adaptive controller based on external force feedback in gait parameter space is proposed and implemented, resulting in the robot to successfully climbing over a stair-type obstacle without any prior knowledge about the environment.
Complete Bifurcation Trees of Independent Period-2 Motions to Chaos in a Parametrically Excited Pendulum
Authors: Guo Yu , Luo Albert C. J. 
Published: November 2019

Abstract
In this paper, bifurcation trees of independent period-2 motions to chaos are investigated in a parametrically excited pendulum. The implicit discrete mapping method is employed to obtain periodic motions in such a system. Analytical predictions of periodic motions are based on the mapping structures and peroidicity. The bifurcation trees of independent period-2 motions to chaos are studied, and the corresponding stability and bifurcation analysis are completed through eigenvalue analysis. Finally, sampled period-2 motions are simulated numerically in comparison to the analytical predictions. The infinite bifurcation trees of independent period-2 motions to chaos can be obtained.