bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of Viscous Fingering in Microchannels With Hybrid-Patterned Surface Using Lattice Boltzmann Method
Authors: Tursynkhan Margulan , Dauyeshova Bagdagul , Adair Desmond , Monaco Ernesto , Rojas-Solórzano Luis 
Published: January 2020

Abstract
In recent years, a large effort has been devoted to the study of the viscous fingering phenomenon in microchannel flows. This phenomenon plays a crucial role in many fields of industry and occurs in geological sequestration of carbon dioxide (CO2), in the secondary and tertiary oil recovery stages. Viscous fingering, also known as the Saffman-Taylor instability, occurs at the unstable interface between two fluids when the less viscous fluid displaces the more viscous fluid which is originally residing in a porous medium. This paper studies viscous fingering occurring between two segregated immiscible fluids, such that the less viscous one is forced into a microchannel where the more viscous fluid initially resides. The 2D microchannel walls are present with a hybrid-patterned configuration such that the top wall is smooth, and the bottom wall is ribbed. The multiphase Shan-Chen Lattice Boltzmann Method (SC LBM) is implemented to capture the complex interfacial phenomenon since this method has proven to accurately describe multiphase interfacial entangling. The LBM is based on the discretization of micro- and mesoscopic kinetic equations and the SC LBM simulation allows us to study the viscous fingering phenomenon in terms of non-dimensional quantities, including capillary number and viscosity ratio. The effect of hybrid-patterned rough walls on fingering formation in a 2D microchannel is investigated and compared to the phenomenon when plain smooth walls are in place. The numerical results show that the SC Lattice Boltzmann multicomponent model provides insightful characteristics associated to the physical nature of the fingering phenomenon in microchannels and the role of adjacent walls.
A Novel Framework of Lightweight Optimization Design of a Prototype Wafer Stage With Control Verification
Authors: Li Yujie , Zhang Ming , Zhu Yu , Li Xin , Wang Leijie 
Published: January 2020

Abstract
Performance requirements of a higher throughput and accuracy in precision motion systems, such as wafer stage used in integrated circuit manufacturing, are ever increasing. The lightweight design, as one of the design methods, can results in less power consumption and less negative environmental impacts for the required high levels of acceleration. The aim of this research is to investigate the advantage of the lightweight design and to mitigate the negative effect caused by the flexible characteristics using an appropriate control method. In this paper, a prototype wafer stage is the analysis object. Since the mass of the horizontal drive motors accounts for a large proportion of the total mass of the wafer stage, a novel lightweight optimization frame based on the minimum motor mass is presented, while a Lorenz motor model based on finite element method (FEM) and artificial neural network (ANN) is firstly constructed. Then the controller adopting the PID with the maximum control bandwidth and pole placement method are designed. Through numerical analysis, the mass of the mover of the mover of this stage is reduced from 10.28 Kg to 6.078 Kg after lightweight optimization. Taking the Moving Average (MA) and Moving Standard Deviation (MSD) of the servo error in Z-direction as the control index, a closed-loop simulation result shows that the lightweight wafer stage can separately fulfil the requirement of the MA and MSD of the servo error in z-direction within 20nm and 30nm just as the current rigid-body wafer stage without the lightweight optimization.
Shape Memory Metamaterials With Adaptive Bandgaps for Ultra-Wide Frequency Spectrum Vibration Control
Authors: Song Yihao , Shen Yanfeng 
Published: January 2020

Abstract
This paper presents a novel shape memory metamaterial, which can achieve adaptively tunable bandgaps for ultra-wide frequency spectrum vibration control. The microstructure is composed of a Shape Memory Alloy (SMA) wire and a metallic spring combined together with bakelite blocks, loaded by a lumped mass made of lead. The adaptive bandgap mechanism is achieved via the large deformation of the metamaterial unit cell structure during the heating and cooling cycle. By applying different heating temperature on the SMA wire, morphing microstructural shapes can be achieved. Parametric design is conducted by adjusting the lead block mass. Finally, an optimized microstructural design rendering a large deformation is chosen. Finite element models (FEMs) are constructed to analyze the dynamic behavior of the metamaterial system. Effective mass density of the unit cell is calculated to investigate and demonstrate the bandgap tuning phenomenon. In the simulation, two extreme shapes are simulated adhering to the experimental observations. The effective negative mass density and the moving trends are obtained, representing the development and shifting of the bandgaps. The width of the bandgap region covers about 50 Hz from the room-temperature state to the heating state. This enables the vibration suppression within this wide frequency region. Subsequently, a metamaterial chain containing ten unit cells is modeled, aligned on an aluminum cantilever beam. An external normal force with a sweeping frequency is applied on the beam near the fixed end. Harmonic analysis is performed to further explore the frequency response of the mechanical system. The modeling results from modal analysis, effective mass density extraction, and harmonic analysis agree well with each other, demonstrating the prowess of the proposed shape memory metamaterial for ultra-wide frequency spectrum control.
Computational Analysis of Combat Helmet Protection Against Blunt Impact to Head
Authors: Tan X. Gary , Bagchi Amit 
Published: January 2020

Abstract
Computational modeling provides significant benefits in assessing the helmet performance and identifying promising helmet designs. We develop multi-fidelity computational tools, representative virtual human head and helmet system models to help the design of next generation combat helmet with improved protection against blunt impact. By integrating the fast-running articulated human with personal protective equipment (PPE) biodynamics model with the high-fidelity human head with combat helmet finite element (FE) model, the multi-fidelity approach can be used to efficiently investigate impact-related traumatic brain injury (TBI) in the real-world scenario. The FE model is used to capture the dynamics of the composite helmet shell, foam pad suspension, retention strap and head while the biodynamics model provides the proper kinematics and boundary conditions for the FE model. An orthotropic elasto-plastic material with damage model is employed for the helmet shell. Enhanced tetrahedral elements are used to model the nearly-incompressible tissues. The head with helmet and without helmet under a severe impact due to a fall caused by blast loading are simulated and compared. The resulting biomechanical responses of head acceleration, shear stresses and strains in brain and mechanical injury criterion as well as helmet energy absorption are used to characterize the performance of helmet system.
Dynamic Parameters and Friction Model Identification of an Industrial Hybrid Robot
Authors: Zhang Binbin , Wang Liping , Wu Jun 
Published: January 2020

Abstract
To obtain higher performance for an industrial hybrid robot, the dynamic control method is utilized to control the robot. For dynamic control, the control performance is directly affected by the accuracy of the dynamic model. This paper investigated a method to establish and identify an accurate dynamic model. First, based on the Lagrangian dynamic equation and the Stribeck friction model, the unidentified dynamic model of the five-DOF hybrid robot is established. Second, identification experiments are carried out. Each of the driving joints performs frequent reciprocating motions individually. In the meantime, the moving speed is gradually increased to obtain driving torques of the respective joint at different moving speeds. Then the dynamic parameters with lower coupling are identified by using the standard deviation index and the least squares methods until all parameters are gradually determined. Finally, the hybrid robot moves a typical trajectory, while the currents of each joint are collected to obtain the driving forces. The actual driving forces, the identified dynamic model, and the unidentified dynamic model are compared. The results show that the identified method could significantly improve the accuracy of the dynamic model. The method proposed in this paper is general and can be applied to the other robots without adding any sensors.
Experimental Investigation of Combustion Behavior of Biodiesel-Water Emulsion
Authors: Singh Gurjap , Hentges Nicholas , Johnson Damion , Ratner Albert 
Published: January 2020

Abstract
Biodiesel has proved to be an attractive alternative fuel for the compression-ignition engine, with its blends of regular petrodiesel being sold at virtually every gas station in the United States. Researchers have explored many of its combustion properties and sought to modify them in the interest of better fuel economy, specific fuel combustion, and lower emissions. The emulsification of biodiesel with water in order to promote microexplosions during the combustion process is one such fuel modification method. Microexplosions fragment the fuel droplet into many smaller droplets, which promote homogeneous combustion, and can result in smoother power output and better fuel economy. Present research analyzes the droplet combustion properties of soy biodiesel with 10% water and 0.1% POLYOX™ polymer. A sub-millimeter droplet is suspended on three 16μm silicon carbide wires and ignited using hot wire loops. The combustion process is recorded at 1000 frames/second by a high-speed CCD camera. Combustion behavior of the emulsified fuel is then analyzed by post-processing the resulting high-speed images. Results show several microexplosion events. Combustion trends are plotted, and combustion rates are determined. Burning rate for the emulsion was found to be very close to that of base fuel, with 2.1% decrease noted. It is hoped that present research will spark further interest in the fuel behavior modification of biodiesel.
An Analytical Study of BMI Effects on Obese Senior Females in Vehicle Frontal Impact
Authors: Xu Huijie , Zhan Zhenfei , Yin Yunlei , Dong Wenxiang , Wang Qingmiao , Chen Ruyi , Jin Xin 
Published: January 2020

Abstract
Prior works showed that elderly females are a vulnerable segment of the population that needs special attention for their safety in traffic accidents. To study the injury performance of this vulnerable group in motor vehicle crashes (MVCs), a finite element model was developed to represent the full body of 70-year-old regular sized female. However, this model did not take the variations in size and shape among this group of people into account. In this study, an adaptive radial basis functions (RBF) methodology is developed to rapidly morph the baseline model to the target models defined by the statistical models of external body surface and the exterior ribcage. High speed frontal crash simulations are subsequently performed to investigate the effects of BMI on impact injuries. The results show that obese senior female occupants sustained higher risks of thorax, femur and head injuries than that of regular sized occupants. While BMI has no linear effect on head and thorax injury.
Design and Evaluation of a Blood-Contacting Medical Device for Improving Functionality and Durability of Vascular Anastomosis
Authors: Singh Gurjap , Esmaeilpour Mehdi , Bhama Jay K. , Ratner Albert 
Published: January 2020

Abstract
An example of vascular anastomosis is coronary artery bypass grafting (or CABG), which is the most common open-heart surgery in the United States today. It is used to treat people with coronary heart disease. Although it generally produces good outcomes, it is not without risk of failure. Due to rotation-related fluid stress on the graft at the point of attachment, possibility of clots forming at extraction and perfusion sites is high. The possibility of endothelialization at the suture joints carries a further risk of flow obstruction. Present research proposes a new blood contacting medical device that is attached to both ends of a vascular graft, and aids in flow rotation at the points of blood extraction and perfusion, thereby alleviating the possibility of clotting at those sites. It also shifts the suture lines such that the endothelialization causes minimal flow obstruction compared to current techniques. Simplified 3D models of both the current grafting technique and the proposed device are evaluated with periodic rectified sine pulse acting as a surrogate for human blood pulse. For both perfusion and extraction, better outcomes were observed for vascular anastomosis with the proposed blood contacting medical device.
MoVE: A Mobility Virtual Environment for Autonomous Vehicle Testing
Authors: Compere Marc , Holden Garrett , Legon Otto , Martinez Cruz Roberto 
Published: January 2020

Abstract
Autonomous vehicle researchers need a common framework in which to test autonomous vehicles and algorithms along a realism spectrum from simulation-only to real vehicles and real people. The community needs an open-source, publicly available framework, with source code, in which to develop, simulate, execute, and post-process multi-vehicle tests. This paper presents a Mobility Virtual Environment (MoVE) for testing autonomous system algorithms, vehicles, and their interactions with real and simulated vehicles and pedestrians. The result is a network-centric framework designed to represent multiple real and multiple virtual vehicles interacting and possibly communicating with each other in a common coordinate frame with a common timestamp.
This paper presents a literature review of comparable autonomous vehicle softwares, presents MoVE concepts and architecture, and presents three experimental tests with multiple virtual and real vehicles, with real pedestrians. The first scenario is a traffic wave simulation using a real lead vehicle and 3 real follower vehicles. The second scenario is a medical evacuation scenario with 2 real pedestrians and 1 real vehicles. Real pedestrians are represented using live-GPS-followers streaming GPS position from mobile phones over the cellular network. Time-history and spatial plots of real and virtual vehicles are presented with vehicle-to-vehicle distance calculations indicating where and when potential collisions were detected and avoided. The third scenario highlights the avoid() behavior successfully avoiding other virtual vehicles and 1 real pedestrian in a small outdoor area. The MoVE set of concepts and interfaces are implemented as open-source software available for use and customization within the autonomous vehicle community. MoVE is freely available under the GPLv3 open-source license at gitlab.com/comperem/move.
An Improved Predictive Model for Effective Thermal Conductivity of Polymer Composites With Non-Dilute Filler Concentrations
Authors: Raza Kabeer , Akhtar Syed Sohail , Arif Abul Fazal M. , Hakeem Abbas Saeed 
Published: January 2020

Abstract
Most of the predictive models for thermal conductivity of composites are derived based on the assumption that the filler concentration in the matrix is dilute. This assumption leads to inaccurate predictions when filler concentration is essentially non-dilute and hence there is a need to propose a model that could handle a non-dilute filler concentration. In this work an improved and realistic model for effective thermal conductivity of polymer matrix composites with non-dilute filler’s concentrations is derived and validated by experiments. The proposed model can handle fillers with variable size and shapes. The derivation is based on the Bruggeman’s differential effective medium theory where the high volume fractions can be obtained by incrementally adding ‘small volume fractions’ into the ‘existing composite’ at each stage. The proposed model is validated by experimentally produced different series of ceramic particles-polymer composites. Differently sized and shaped alumina (Al2O3) & aluminum nitride (AlN) particulate fillers, and high density polyethylene (HDPE) & polypropylene (PP) matrices were used as the variable ingredients. Using different combinations of filler, matrix and particle size six different series of composites were produced with variable filler concentrations up to 50% by volume. The microstructure of the produced samples was studied by field emission scanning electron microscope to relate the morphology with the predictions. The predictions of proposed model are found in close agreement with the measured thermal conductivities. To understand the detailed effects of different parameters, parametric studies are presented and discussed. It is found that aspect ratio of particulate fillers is the most sensitive parameter to enhance effective thermal conductivity. Overall, the proposed model is proven to be useful in composite material design for heat transfer applications. It is expected that the proposed model will open new doors for the researchers and polymer composite industry to develop new composite designs for achieving ultrahigh thermal conductivities.
Reviewing Machinability of Fibre-Reinforced Polymer (FRP)/Metallic Stacks Using MQL
Authors: Ghoshal Abhishek , Khan Adnan , Zahid Moosa , Pervaiz Salman , Kannan Sathish 
Published: January 2020

Abstract
Minimum quantity lubrication (MQL) assisted techniques are gaining popularity because of their lower environmental impact and cost effectiveness. Fibre reinforced polymers (FRP) are mainly utilized in the aerospace and automotive sectors, because of their high strength-to-weight ratio, low coefficient of thermal expansion, high corrosion resistance, high modulus to weight ratio and improved tensile strength. Besides that, they are extremely light weight and suitable for structural applications. For fibre reinforced polymers (FRP) composites, all of these properties in combination provide superior functional performance. In a wide range of applications dissimilar material stack-ups of composites and aluminum and/or titanium are used for wing or tail plane structures. Mostly these fibre reinforced polymers (FRP) composites are drilled to provide options for their assembly with other components. However, machining of these fibre reinforced polymers (FRP) composites is very hectic task. It is due to their high abrasive nature and high heat resistance. In this paper, the machinability of fibre reinforced polymers (FRP) composites was explored and reviewed when machined using minimum quantity lubrication (MQL). The study was conducted by systematic selection of experimental and numerical studies from the latest published literature in state of the art. The study reviewed the effects of different parameters on the tool wear, thrust force, work-piece hole diameter, burr height and chip formation. The study provides critical insights about the potential and understanding of machining fibre reinforced polymers (FRP) composites under minimum quantity lubrication (MQL) assisted methods.
Estimates of Area, Output and Levelized Energy Cost of Solar Energy Schemes in Saudi Arabia
Authors: Alabdulkarem Abdullah , Abdulghani Mohannad 
Published: January 2020

Abstract
Saudi Arabia consumes a significant amount of oil domestically for transportation and energy generation purposes. The booming population and high power consumption contribute to a sharp increase in power demands. The Saudi electric utility is investing heavily in upgrading the power grid and generation infrastructure to keep up with surging consumption. The desert belt in Saudi Arabia is exposed to substantial levels of solar irradiance, which renders Saudi Arabia a good candidate for large scale solar energy schemes. Upper and lower limits of cost and energy output are to be estimated for such ambitious endeavors to enter the national and international conversations. In this work, an attempt was made to estimate the area of photovoltaic panels and levelized energy cost required for generating the peak load and baseload power demands of the entire country and contrast them against the subsidized and unsubsidized cost of electricity in the kingdom. The levelized energy cost was found to be higher than the unsubsidized cost of electricity in the kingdom. The area required for both schemes was not found to be a limiting factor when compared to the available land area.
Effect of Motion Type on Joint Contact Forces
Authors: Schmitz Anne , Norberg Jaclyn 
Published: January 2020

Abstract
Race walking has grown over the past decade because it provides exercise without the high impact loads of running. In fact, race walking has been shown to result in decreased ground reaction forces. We predict these lower ground reaction forces will extend to knee joint loading as well, thus explaining the decrease rate of knee osteoarthritis in race walkers compared to runners. This is a secondary analysis of instrumented motion capture data collected from fifteen competitive race walkers as they ran and race walked over a force plate. A Visual3D to OpenSim pipeline was used to create muscle actuated forward dynamics simulations of race walking and running. The resulting muscle forces were subsequently used to actuate a discrete element knee model to calculate joint forces. The peak tibiofemoral joint contact load during race walking was 18% lower than the load during running. This load was distributed between the medial and lateral compartments such that the medial load was 27% lower and the lateral load 35% lower in race walking. This suggests race walking is a lower impact exercise safer for the joints. This may be advantageous for people who would like to exercise at a higher intensity that walking provides but have joint problems, e.g. those with osteoarthritis.
Univariate and Multivariate Gauge Repeatability and Reproducibility Analysis on the High Frequency Dynamic Mechanical Analysis (DMA) Measurement System
Authors: Esmaeeli Roja , Aliniagerdroudbari Haniph , Hashemi Seyed Reza , Al-Shammari Hammad , Alhadri Muapper , Farhad Siamak 
Published: January 2020

Abstract
The quality of the collected data from a measurement system affects eventual decision making process. Therefore, the reliability of any measurement system is an important factor to be studied. Gauge repeatability and reproducibility (Gauge R&R) is the standard method to evaluate the measurement system and assess the adequacy of variation in the measurement data. Gauge R&R is a statistical tool which evaluates two main characteristics of the measurement system: repeatability and reproducibility. The Dynamic Mechanical Analysis (DMA) is a common measurement system for studying the dynamic mechanical properties of viscoelastic materials such as polymers. The newly developed High Frequency Dynamic Mechanical Analysis (HFDMA) is able to directly run the simple shear test at high frequencies without changing the specimen temperature. The complex shear modulus and damping factor of the viscoelastic materials are reported by the HFDMA system. In this study the uni-variable Gauge R&R study based on Analysis of Variance (ANOVA) is done on each measured characteristic of the HFDMA measurement system. The source of variations for each characteristic is distinguished. Then the multivariate Gauge R&R based on the Multivariate Analysis of Variance (MANOVA) is done and the percentage of multivariate Gauge R&R for the measurement with the multiple variables is reported. The results indicate that the HFDMA measurements are both repeatable and reproducible. Thus, the new HFDMA can be used as a measurement system to measure the mechanical properties of viscoelastic materials at high frequencies.