bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vortex Generator Designs to Improve Flow for a Vehicle Side-View Mirror
Authors: Dong Zulong , Jawad Badih , Liu Liping , Metwally Hossam 
Published: January 2020

Abstract
The unsteady airflow over automotive side-view mirrors is a typical source of turbulence which creates extra drag force, aerodynamic noise and vibration. A CFD analysis is presented for vortex generators (VGs) application on the vehicle side-view mirrors for the purpose of flow improvement. Vortex generators are used to delay flow separation and increase the control surfaces which affect the drag force and down force of the vehicle. Reduced drag force can potentially increase fuel economy, and an increased downforce will increase vehicle grip force and improve vehicle stability which is essential for racing cars. This paper presents practical solutions for mitigating flow turbulence and adjusting down force for existing side-view mirrors.
Four VG configurations were designed and numerically analyzed in combination with the baseline model at air speeds ranged from 15 to 80 miles per hour. This research investigated the effect of each VG configuration on the side-view mirror’s aerodynamic performance. The turbulent flow through the side-view mirror were analyzed by using standard K-epsilon (K-ε) Reynolds-averaged Navier-Stokes method. The drag and down forces results were obtained and compared with the baseline model. The CFD analysis concluded the following: (1) Setting the VGs with a 5 degree attack angle on the upwind face of the mirror slightly reduced the drag force. (2) Setting the VGs at the top of the mirror surface greatly increased the downforce with a large drag force increase.
Quantitative Characterisation of Pearlite Morphology in Hot-Rolled Carbon Steel
Authors: Musonda Vincent , Akinlabi Esther T. 
Published: January 2020

Abstract
During the hot rolling of carbon steel, austenite phase transforms into a pearlitic morphology, which essentially is a matrix of ferrite lamellae (α-Fe) and cementite (Fe3C). This transformation occurs at the cooling bed after an equalisation temperature of around 600 °C. Pearlitic steels find their use in ropes for bridges and elevators, rails, and tyre cords among others. Characterisation of microstructure has not been broadly applied to pearlitic steels because of their complex microstructures. Therefore, the characterisation of this morphology becomes inevitable, in order to identify potential weaknesses in the matrix. In this study, hot-rolled reinforcement bars (rebars) produced from recycled steel and direct reduced iron (DRI), were used for microstructural examination using standard metallurgical procedures. Although the optical microscope (OM) and scanning electron microscope (SEM) were used to obtain qualitative microstructure, they could not characterise the pearlite morphology quantitatively because of their three-dimensional (3D) limitation. Hence, the image analyser - Gwyddion Software, was used to quantify the pearlite morphology of these Y16 rebars. The results indicate that the pearlite colony is characterised by 3D single interpenetrating crystals of ferrite and cementite running parallel to each other due to their common growth during the transformation process of austenite. It was further observed that, the dimensional properties of the phases in the morphology in terms of their width and Interlamellar spacing (S), including the roughness of the pearlite colony can vary significantly. These results could be used to enhance the processing methodology of the industrial production processes.
Investigation of the Effects of Simultaneous Internal Flow Boiling and External Condensation on the Heat Transfer Performance
Authors: Kabir M. M. , Lee Sangsoo 
Published: January 2020

Abstract
Recent leaps in heat dissipation make it difficult for typical heat exchangers to meet the requirements of the advanced applications even with the maximally obtainable heat transfer performance associated with a single-phase process. Especially high heat flux applications such as thermal management in microelectronics, advanced material processing, and nuclear fusion reactors require extreme heat transfer methods to overcome the current limits.
In this study, a heat exchanger adopting simultaneously two-opposite, phase-change heat transfer processes (internal flow boiling and external condensation) was proposed and analytically investigated. The phase-change heat transfer analyses were conducted for internal flow boiling and external condensation at a test section and the heat transfer performances were compared with that of a system with an internal single-phase, liquid flow process. It is found that the proposed heat exchanger configuration with an internal flow boiling can substantially enhance the heat transfer performances and provide better methods to manage the temperature difference comparing to those with an internal single-phase heat transfer due to its significant increase in a heat transfer coefficients and constant temperatures during phase-change processes.
Additionally, this study also explains the design for a test rig to evaluate and validate the results in detail. The test rig consists of an internal flow boiling loop with a test section, an external condensation loop, sensors, auxiliary monitoring parts, and controlling and data acquisition systems. Thermodynamic cycle, pressure drop, and heat transfer analyses were conducted to determine the conditions and the specifications of components and sensors for the test rig.
Macro-Scale Geometric Voids to Alter Stress Wave Propagation in Solids
Authors: Florio C. S. 
Published: January 2020

Abstract
Structural discontinuities, such as voids or inclusions in otherwise uniform, solid materials have previously been successfully implemented to alter the propagation of various types of waves through a range of materials and structures. Much of this work has focused on micro-scale features and low energy waves. The disruption of waves carrying larger amounts of energy currently relies mainly on large material deformation, typically with a layer of the structure becoming permanently damaged in order to protect other portions. However, the ability to disrupt, alter, direct, and control higher energy waves without significant damage to the material or structure can be desirable.
Microscale features can disperse wave fronts, scattering their energy and reducing the potentially damaging effects of the concentrated loads carried in these waves. However, the control of the distribution of these microscale features throughout the material and structure can be difficult, limiting the ability to use these materials to control the dispersion of the wave energy or direct it to more desirable regions in the structure. Macro-scale features can be more easily formed into patterns and arrangements which can be designed for specific wave-controlling or directing properties. Additionally, materials and structures with macro-scale discontinuities can result in a greater change in energy per inclusion and a greater spatial range of their effects throughout the domain of the material. Therefore, they have the potential to be used to address input waves of higher energy. The use of macro-scale features may provide added manufacturing-based benefits, particularly with the more widespread development and use of advanced manufacturing methods, such as additive manufacturing.
This study examines the feasibility of the use of arrays of macro-scale features to direct and control input stress waves. The effect of the shape and arrangement of macro-scale geometric features is studied under a range of orders of magnitudes of the incident stress wave. Methods are developed in this work to predict the propagation of the stress waves through the material and to quantitatively assess the effects of these included arrays of structural, geometric discontinuities. The results of this study are used to evaluate the feasibility of the use of these geometric macro-scale arrays to control the propagation of stress waves in structures while limiting gross material deformation and damage to the overall structure.
Development and Design of the Dynamic Vibration Absorber Using Magneto-Rheological Elastomer for the Weight and Power Consumption Saving
Authors: Terashima Osamu , Nakata Mika , Komatsuzaki Toshihiko 
Published: January 2020

Abstract
In this study, a broadband frequency tunable dynamic absorber was designed and fabricated based on the primary design principle of a mass damper. A magneto-rheological elastomer that can change the relative stiffness when an external magnetic field is applied was used to control the natural frequency of the movable mass of the absorber. A coil to generate the magnetic field was also used as a movable mass to decrease the total weight and to create a constant closed loop of the magnetic force. The hammer impact test results show that the present absorber could change its natural frequency with minimal electric power and had a constant damping ratio. Experimental results of vibration absorbing of an acrylic flat plate show that the proposed absorber could change the natural frequency of the movable mass and reduce the vibration over a wide band by constantly applying the optimum current to the coil in the device with a small power consumption (less than 10 W). Therefore, the proposed absorber works effectively. Further, a technique to determine the electric current applied to the coil automatically based on the phase difference of the vibrational acceleration of the movable mass and the vibrating objective was also presented.
The Design and Analysis of a New Solar-Module Automated Cleaner
Authors: Martin-Garcia Oscar , Huhmann Brianna , Dryden Alec , Duan Shawn 
Published: January 2020

Abstract
In the photovoltaic industry, it is very important that solar modules are kept clean and free of particulates so that the maximum amount of light can get through to the solar cells inside the glass. The development of the new solar-module automated cleaner (S-MAC) is presented in this paper could potentially help keep residential arrays clean and operating at peak efficiency.
The design and analysis of the S-MAC is detailed. The S-MAC went through a series of iterative design, but a final design prevailed. In this final design, a cleaning module is deployed via stackable arms and power screws. The stackability of the arms and power screws allows the reach of the cleaning module to vary accounting for arrays that are asymmetric. The arms will also be translated across the array frame via rack and pinion. Thus, the S-MAC product will be adaptable to arrays of any size and even arrays of varying width. Calculations concerning the stresses on the arms during operation as well as calculations concerning how many supports are required to reduce stress on the glass, have been completed and are included in the following sections.
Self-Vibration Analysis of the Free-Fall Absolute Gravimeter
Authors: Li Zhenxing , Wu Kang , Wen Yi , Yao Jiamin , Guo Meiying , Wang Lijun 
Published: January 2020

Abstract
The ballistic free-fall absolute gravimeters are widely used in acquiring information of gravity field and the self-vibration of the absolute gravimeter is crucial for high precision gravitational measurement. The self-vibration of the T-1 absolute gravimeter has a multi-directional full-band excitation. The resulted horizontal swing has the major impact, since the T-1 absolute gravimeter is simplified as a cantilever beam. A laser vibrometer was applied to directly measure the mechanical self-vibration. The frequency of self-vibration has a nonlinear effect on the measurement error of g, and the peak frequencies should be avoided. The vibration signal was analyzed in time and frequency domain by continuous wavelet transform (CWT). The close frequency profiles were measured in the scalogram and the beat vibrations were observed in time domain as the results of the horizontal swing. The 38 Hz self-vibration had the dominating effect on the measurement error of g for T-1 absolute gravimeter. After optimizing the structure of the tripod, the dominating frequency increased from 38 Hz to 42 Hz. A 11% increase of the vibration frequency can reduce the measurement error of g.
Research on Actuation Properties of Shape Memory Alloy Wire-Based Flow Effector Actuator
Authors: Wu Miao , Wu Lianmei , Yang Fei , Yue Honghao , Yu Hongying , Lu Yifan , Wang Jian , Wang Gang 
Published: January 2020

Abstract
The character of supersonic air-to-air missile is centered with capturing the target or evading the attack of target. Hence, active disturbance control method is proposed by means of using nose-mounted micro-structures what are called flow effectors. In general, flow effector actuator is buried inside the projectile. For satisfying the active disturbance control, the flow effector actuator pushes up from the cone nose of the projectile. For the reason of the air pressure and shape memory alloy wire actuation characteristic, it is necessary to calculate the input stiffness/output stiffness of the transmission mechanism of flow effector actuator.
This paper analyses the system dynamics using the matrix method for serial compliant mechanism. Based on the stiffness characteristics of the corner filleted compliant mechanism, the shape memory alloy wire-based actuator analysis model is built. Besides, the stiffness model and output capacity of the flow effector actuator system are given. The actuation properties of shape memory alloy wire-based flow effector actuator by systematic approach is described, which contains kinematic analysis, static analysis of the system, and using the shape memory alloy strain-stress relationship under high temperature. Several transmission mechanism experiments are performed and the results indicate that the stiffness calculation methods proposed agree well with the experimental results. Flow effector actuator actuation properties test platform is setup and the input displacement and external load is tested.
An Improved Holographic Microwave Breast Imaging Based on Deep Neural Network
Authors: Wang Lulu 
Published: January 2020

Abstract
Microwave imaging offers excellent potential for breast cancer detection. Deep learning is state-of-the-art in biomedical imaging, which has been successfully applied for biomedical image classifications. This paper investigates a deep neural network (DNN) based classification method for identifying breast lesion in holographic microwave image (HMI). A computer model is developed to demonstrate the proposed method under practical consideration. Various experiments are carried out to evaluate the proposed DNN-based HMI for breast lesion classification. Results have shown that the proposed method could serve as a helpful imaging tool for automatically classifying different types of breast tissues.
Eccentricity of Rotor Prediction of Aero-Engine Rotor Based on Image Identification and Machine Learning
Authors: Zhang Zihao , Guo Junkang , Sun Yanhui , Hong Jun 
Published: January 2020

Abstract
The eccentricity of rotor seriously affect the vibration and reliability of aero-engine. Due to the machining error of parts, it is very important to accurately predict the error propagation in assembly. A method based on image recognition and machine learning is proposed to predict the eccentricity of rotor. Firstly, by analyzing and calculating the axial and radial runout error data, the error is mainly concentrated in the first 30 orders of the Fourier series. Secondly, based on the mapping relationship between profile trajectory and eccentricity of rotor, the feature information of the profile trajectory is extracted by constructing the complex domain autoregressive (CAR) model for the radial and axial direction error profile trajectory. Then use the finite element method to calculate the rotor eccentricity. Using the feature information as the input of the neural network, the rotor eccentricity is assembled as the output of the neural network, and the radial basis function (RBF) neural network is built to predict the rotor eccentricity. Theoretical and experimental results show that the proposed method has good enforceability, high accuracy, short calculation time and high engineering application value. In addition, this method can not only be applied to predict the eccentricity of aero-engine rotor flange assembly, but also can be used in the general field of interference fit of assembly.
Lattice Boltzmann Modelling of Contact Angle and Hysteresis Under Homogeneous and Heterogeneous Dynamic Wetting Regime
Authors: Zhumatay Nursultan , Dauyeshova Bagdagul , Adair Desmond , Monaco Ernesto , Rojas-Solorzano Luis 
Published: January 2020

Abstract
The contact angle is a measurement of wettability of a solid surface resulting from molecular attraction or repulsion at the encounter point between a liquid-gas interface and a wall. To date, the determination of the contact angle is commonly performed experimentally with very limited numerical modelling, due to the complex nature of the intermolecular forces at the liquid-gas-solid contact point, even in static conditions. This investigation presents the numerical modelling of the contact angle in static and dynamic conditions on homogeneous and heterogeneous wetting regimes using the multiphase Shan-Chen Lattice Boltzmann Model (SC-LBM). The dynamics of the phenomenon is modelled firstly through a statically suspended droplet and secondly through a sessile droplet subject to the shear flow of air. The Wenzel and Cassie-Baxter states are well reproduced as the response to surface roughness homogeneity. Numerical results demonstrate the excellent suitability of the multiphase SC-LBM for this problem. Furthermore, contact-angle hysteresis is determined under the homogeneous wetting dynamic regime. Two different motion modes were observed during the investigation of the contact angle hysteresis.
Effect of Cryogenic Temperature Rolling on High Speed Impact Behavior of AA 6082 Thin Targets
Authors: Dubey Rahul , Allavikutty Raja , Velmurugan R. , Jayaganthan R. 
Published: January 2020

Abstract
Aluminium alloy AA 6082-T6 was rolled at cryogenic and room temperatures to final thickness of 0.5 mm after 75% thickness reduction and subjected to high speed impact. The deformed alloy was investigated for its ballistic properties due to potential applications in aerospace and automotive sectors. The cryogenic and room temperature rolled samples were subjected to normal high-speed impact using a gas gun arrangement to shoot nosed projectiles at velocities higher than the ballistic limits. Phantom ‘V611’ high-speed camera was used to measure the initial and residual velocities of the projectile. Nano-indentation was performed to relate hardness of the initial sample with the observed impact behaviour. Detailed fractographic studies were conducted using Scanning Electron Microscopy (SEM) to substantiate the possible failure mechanisms upon impact. Electron Backscatter Diffraction (EBSD) and Energy Dispersive X-ray Spectroscopy (EDS) were used to characterize the microstructure of the deformed samples.
The high speed impact data is correlated with the metallographic observations in this study.
Optimization of Machining Parameters During Turning of Tungsten Heavy Alloys Using Taguchi Analysis
Authors: Kiran Sagar Chithajalu , Priyadarshini Amrita , Gupta Amit Kumar 
Published: January 2020

Abstract
Tungsten heavy alloys (WHAs) are ideally suited to a wide range of density applications such as counterweights, inertial masses, radiation shielding, sporting goods and ordnance products. Manufacturing of these components essentially require machining to achieve desired finish, dimensions and tolerances However, machining of WHAs are extremely challenging because of higher values of elastic stiffness and hardness. Hence, there is a need to find the right combination of cutting parameters to carry out the machining operations efficiently. In the present work, turning tests are conducted on three different grades of WHAs, namely, 90WHA, 95WHA and 97WHA. Taguchi analysis is carried out to find out the most contributing factor as well as optimum cutting parameters that can give higher metal removal rate (MRR), lower surface roughness and lower cutting forces. It is observed that feed rate is the most prominent factor with percentage contribution varying in the range of 46–61%; whereas cutting speed has least effect on cutting forces, especially for 95WHA and 97WHA. Optimum values of forces, surface roughness and MRR and the corresponding machining parameters to be taken are presented. It is observed that 95W WHA has slightly better machinability as compared to other two grades since it gives highest MRR with lowest cutting forces and surface roughness values. The optimum machining parameter settings, so predicted, can be utilized to machine WHAs efficiently for manufacture of counter weights and inertial masses used in aerospace applications.
Analysis of Labyrinth Seal Flow Patterns to Improve Bulk Flow Code Predictions
Authors: Gibbons Nathaniel , Watson-Kassa Cori , Goyne Christopher , Wood Houston 
Published: January 2020

Abstract
Non-contacting annular seals are frequently used in turbomachinery to reduce leakage of a fluid through a section with a large pressure differential. A typical type of non-contacting seal is the labyrinth seal, where circumferential grooves are cut into the rotor, stator or both. Using a tortuous path, labyrinth seals reduce leakage by dissipating the fluid’s kinetic energy through viscous forces caused by the formation of vortices in each seal groove.
Due to a lower cost when compared to experimental measurements, bulk flow codes are frequently used for predicting seal contributions to rotordynamic performance. Existing seal codes use constant or linear values for the fluid film thickness at different seal sections and display inaccuracies in their prediction of velocity and pressure profiles and rotordynamic coefficients for labyrinth seals when compared to experimental data. The primary objective of this study is to determine the effect of implementing an effective film thickness into the governing bulk flow equations on the code prediction of axial velocity and pressure profiles.
Simulations were run using ANSYS CFX with cross-sectional models of individual seal grooves. Seal parameters, including inlet circumferential velocity and rotor speed, were varied to better understand the behavior of the film thickness under various operating conditions. Streamlines were used to determine the maximum film thickness and an effective film thickness profile that can be used in the modified bulk flow code. Modified governing equations were developed, and predictions for the axial profiles resulting from the modified code solutions for the zeroth order governing equations are compared to CFD results and previous code predictions for improved accuracy. Preliminary results for a set of cases indicate far higher accuracy when an effective film thickness is used and represent the first results from a seal bulk flow code that implements a nonlinear effective film thickness. Improvement in code prediction of flow behavior across the seal, and subsequently in the seal codes accurate prediction of rotordynamic coefficients, allows for the design of more efficient and effective seals and machine systems.