bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Numerical Study of Forced Convection Casson Nanofluid Flow Past a Wedge With Melting Process
Authors: Endalew Mehari Fentahun , Sarkar Subharthi 
Published: February 2021

Abstract
A numerical investigation is carried out to analyze steady two dimensional Casson nanofluid flow past a wedge with melting. The partial differential equations that govern the nanofluid flow are transformed into highly nonlinear coupled ordinary differential equations by employing similarity transformation. Thereafter, numerical solutions of these governing equations are obtained by MATLAB routine bvp4c. A special case of the present study is compared with an existing solution in literature and is found to be in good agreement. The effects of pertinent physical entities on the nanofluid velocity, nanofluid temperature, and nanoparticle concentration are represented graphically, while skin friction, Nusselt number, and Sherwood number are recorded in tabular form. We observed that, with an increase of wedge angle parameter, nanofluid velocity and local skin friction increase. However, when the melting parameter increases, nanofluid temperature and heat transfer rate decrease. This study would be useful in unfurling novel applications of Casson nanofluids in cooling devices and heat sinks.
Research on Dynamic Characteristics of the High-Speed Cable Force Transmission
Authors: Hou Senhao , Tang Xiaoqiang , Wang Yuheng , Wang Dianjun 
Published: February 2021

Abstract
During the landing and detection missions of the Moon, Mars, and asteroids, due to the complexity and unpredictability of the landing process, it is necessary and critical to carry out simulation tests on the ground to simulate the stress state during the separation of the backshell from the lander. A high-speed cable-driven mechanism adopted. The cable force is different at the end actuator and the drum. There are many factors causing this difference, such as high acceleration, cable stiffness, cable density, cable length. In this paper, the cable force transmission of spacecraft during high-speed separation is studied. The dynamic model of high-speed cable-driven mechanism is established based on Newton principle, then the trial function is introduced, and the second-order partial differential equation is solved by using the method of space discretization. The force relationship of the cable in the process of motion is obtained, and the influencing factors of the cable force are explored. Finally, the correctness of the research content in this paper is verified by numerical simulation and experiment. The results show that the model can accurately simulate the force state of the cable, and it has guiding significance for the active high-speed separation test of spacecraft.
Development of a Model of Synergistic Effects Between Deterioration Mechanisms and Damage in Woven Glass Fiber Reinforced Polymeric Composite Structure
Authors: Li Zhiye , Lepech Michael 
Published: February 2021

Abstract
The adoption of fossil-based hydrocarbon polymer composites has been successful in both the automotive and aircraft industries, and is rapidly expanding into buildings and civil infrastructure. One challenge to broader adoption of polymer composites in buildings and civil infrastructure is a limited ability to model the synergistic effects of the combined physical/chemical processes of environmental exposure and mechanical loading. Unlike other building materials, long-term experience and field performance data of polymer composites in buildings and civil infrastructure applications does not exist. The first and largest composite building system used in a high-rise exterior in the US is the facade of the San Francisco Museum of Modern Art (SFMOMA) completed in 2015. Since historical, experience-based service life models for composite building applications are not available, it is crucial to build multiphysical-based models in order to predict composite service life performance on a semi-centennial or centennial time scale.
This paper uses a parametrically homogenized deterioration model to hierarchical model the thermo-chemical-mechanical degradation at the structural length scale and proposes this computational model as a component to complete a new multi-physics-based service life prediction framework. This effort consists of three steps: (i) use the theory of synergistic effects between ultraviolet exposure and moisture exposure degradation processes developed by the authors to generate a residual, deterioration-induced damage variable field, (ii) implement the residual damage field as the initiation of a continuum damage model (CDM) at structure length scale, and (iii) recreate one 3D façade plate of the SFMOMA and perform parametric damage analysis.
Application of Alternative Support Fixture System in Vibration Suppression of Thin-Walled Parts
Authors: Liu Ze , Sun Yu , Wang Yu 
Published: February 2021

Abstract
The machining vibration of thin-walled parts affects the quality of the products. Thus, this paper proposes a new alternative support fixture system for vibration suppression of thin-walled parts. The system includes two movable supporting heads, which are periodically repositioned along the machining path in the form of alternating support to support the area close to the cutter, so as to improve the rigidity of the actual machining position of the thin-walled part. Around this new system, a dynamic model is established to analyze the workpiece vibration. Takeing as an example simply suppoted thin-plate, the influence of the supporting head’s location, stiffness coefficient and damping coefficient on vibration suppression are numerically analyzed in this paper. The result of the simulation demonstrates the alternative support fixture system is effective in vibration suppression of thin-walled parts.
Potential Waste Heat Recovery Analysis From Molten Steel Slag: The Case Study of Sidenor Steelworks in Basauri (Spain)
Authors: Ortega-Fernández Iñigo , Arribalzaga Peru , Bielsa Daniel , Fernández Leixuri , Unamuno Iñigo 
Published: February 2021

Abstract
Every day huge amount of energy is released to the atmosphere in form of waste heat. The search of a cleaner and more efficient society, not only at industrial level but also at domestic level, should avoid this type of emissions. Steelmaking is an example of an industrial sector with high optimization potential in energy management. In this line, this work presents the main outcomes of the investigation carried out in the search of a technical solution for heat capture and reutilization from one of the main waste heat streams in the steelworks, the molten slag. For this purpose, a piping system embedded in the slag pit soil is proposed as satisfactory solution for the heat capture operation. Besides, the internal applicability of this recovered heat is also addressed. Overall, the analysis carried out allows the identification of the main process parameters that limit the heat recovery potential from the molten slag. At the same time, the investigation provides accurate results of the maximum energy that can be recovered from the slag if the proposed technology is implemented (around 306 kWht per casting, what represents the 6.3% of the total available energy). The work is completed with a preliminary techno-economic analysis to conclude with the viability assessment. This analysis shows a depreciated payback period of the proposed technology below 7 years.
Non-Destructive Evaluation of the Degradation of Ni-Base Superalloy in the Air by Reflectance Spectrum Analysis
Authors: Kasama Shin , Suzuki Ken , Miura Hideo 
Published: February 2021

Abstract
Thermal power generation is required to be highly efficient due to concerns such as environment and energy problems. In order to improve its efficiency, it is thermodynamically essential to increase operating temperature. In addition, since thermal power generation is expected to control its output to be coexistent with renewable energies of which output varies frequently depending on weather, not only simple fatigue or creep load but also creep-fatigue load is applied to its component because it is required to assure the safe and stable energy supply under random output of the renewable energies. Since the effective lifetime of heat-resistant alloys decreases drastically under creep-fatigue load, however, it is very important to develop a non-destructive inspection method which can detect the degradation of the crystallinity of the alloys such as local plastic deformation, local oxidation, and local change of micro texture (segregation/precipitation). In this research, the reflectance spectrum analysis of the component elements was applied to the observation of the change in the local crystallinity of Ni-base superalloy (Alloy 617). A creep-fatigue test was applied to a small specimen, and the change of the local reflectance spectrum was measured under the irradiation of a white light. It was confirmed that the change of the surface roughness in the damaged area caused by plastic deformation and the growth of the surface oxide were successfully observed by the spectrum analysis. In addition, the distribution of fine carbides and nitrides was visualized by the spectrum analysis. It was also confirmed that a thick Cr-rich oxide layer grew at the grain boundaries only in the heavily damaged area. Finally, it was concluded that the creep-fatigue damage was clearly visualized by the spectrum analysis.
Computational Model of Radiofrequency Ablation of Cardiac Tissues Incorporating Thermo-Electro-Mechanical Interactions
Authors: Singh Sundeep , Melnik Roderick 
Published: February 2021

Abstract
The application of radiofrequency ablation (RFA) has been widely explored in treating various types of cardiac arrhythmias. Computational modelling provides a safe and viable alternative to ex vivo and in vivo experimental studies for quantifying the effects of different variables efficiently and reliably, apart from providing a priori estimates of the ablation volume attained during cardiac ablation procedures. In this contribution, we report a fully coupled thermo-electro-mechanical model for a more accurate prediction of the treatment outcomes during the radiofrequency cardiac ablation. A numerical model comprising of cardiac tissue and the cardiac chamber has been developed in which an electrode has been inserted perpendicular to the cardiac tissue to simulate actual clinical procedures. Temperature-dependent heat capacity, electrical and thermal conductivities, and blood perfusion rate have been considered to model more realistic scenarios. The effects of blood flow and contact force of the electrode tip on the efficacy of a fully coupled model of RFA have been systematically investigated. The numerical study predicts that the efficacy of RFA is significantly dependent on the thermo-electro-mechanical parameters of the cardiac tissue.
Spin Stabilization of an Air Ambulance Litter
Authors: Forden Christopher , Trinidad Yanuel , von Chance-Stutler Ryan , Bellocchio Andrew , Bluman James , Lanzerotti Mary 
Published: February 2021

Abstract
This paper proposes a new approach to stabilize the spin of a suspended litter during air ambulance rescue hoist operations. Complex forces generated by the helicopter’s downwash may cause a patient suspended in a rescue litter to spin violently. In severe cases, the spin destabilizes the suspended load, risks injury to the patient, and jeopardizes the safety of the aircrew.
The presented design employs an anti-torque device to arrest the spin that is safer and faster than a tagline and is without the tactical constraints of the tagline. The device follows tailored control laws to accelerate a flywheel attached to the litter, thereby generating sufficient angular momentum to counteract the spin and stabilize the suspended litter. An inertial measurement unit (IMU) measures the position, angular velocity, and angular acceleration of the litter and delivers this information to a microcontroller.
The research and prototype design were developed under the support of the U.S. Army 160th Special Operations Aviation Regiment (SOAR).
Evaluation of Thermal Displacement Ventilation in Contamination Purging Inside a 60-Person Built-in-Place Refuge Alternative (BIP RA) in an Underground Coal Mine
Authors: Bickson Joseph , Yantek David , Srednicki Justin , Carr Jacob , DeGennaro Cory , Reyes Miguel 
Published: February 2021

Abstract
Federal regulations require the installation of refuge alternatives (RAs) in underground coal mines to ensure miners’ survivability after a fire or an explosion where escape is impractical or even impossible. Both fires and explosions can generate dangerous or even lethal levels of carbon monoxide (CO) in a mine. As part of their function, RAs must be able to isolate miners from a CO-contaminated mine environment and to purge any CO that might enter the RA as miners enter it. In 2018, researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted purging research in a built-in-place (BIP) RA with a borehole air supply by testing 12 different mixing ventilation system configurations (MVSCs). Recently, NIOSH researchers evaluated the use of a thermal displacement ventilation system configuration (TDVSC) to purge a 60-person BIP RA using a borehole air supply. As in previous research, NIOSH researchers tested the TDVSC with the flow rates of 750 SCFM and then 1,000 SCFM. For each of the flow rates, the results showed that the average purge time for the more expensive TDVSC is within two minutes of the average purge times of previously tested MVSCs. Manufacturers can use this information to not only pursue 30 CFR Part 7 approval from the Mine Safety and Health Administration (MSHA), but also to determine the most practical method to purge contaminants inside RAs.
Assessment of Invasive Fractional Flow Reserve Procedures Using Computational Fluid Dynamics
Authors: Abuouf Yasser , Albadawi Muhamed , Ookawara Shinichi , Ahmed Mahmoud 
Published: February 2021

Abstract
Coronary artery disease is the abnormal contraction of heart supply blood vessel. It may lead to major consequences such as heart attack and death. This narrowing in the coronary artery limits the oxygenated blood flow to the heart. Thus, diagnosing its severity helps physicians to select the appropriate treatment plan. Fractional Flow Reserve (FFR) is one of the most accurate methods to pinpoint the stenosis severity. The advantages of FFR are high accuracy, immediate estimation of the severity of the stenosis, and concomitant treatment using balloon or stent. Nevertheless, the main disadvantage of the FFR is being an invasive procedure that requires an incision under anesthesia. Moreover, inserting the guidewire across the stenosis may result in a ‘tight-fit’ between the vessel lumen and the guidewire. This may cause an increase in the measured pressure drop, leading to a false estimation of the blood flow parameters. To estimate the errors in diagnosis procedures, a comprehensive three-dimensional model blood flow along with guidewire is developed. Reconstructed three-dimensional coronary artery geometry from a patient-specific scan is used. Blood is considered non-Newtonian and the flow is pulsatile. The comprehensive model is numerically simulated using boundary conditions. Based on the predicted results, the ratio between pressure drop and distal dynamic pressure (CDP) is studied. The predicted results for each case are compared with the control case (the case without guidewire) and analyzed. It was found that simulating the model by placing the guidewire at a full position prior to the simulation leads to an overestimation of the CDP as it increases by 34.3%. However, simulating the procedure of guidewire insertion is more accurate. It shows that the CDP value increases by 7%.
CFD Analysis and Improvement on an Insertion Electromagnetic Flowmeter
Authors: Ma Haibo , Silaen Armin K. , Zhou Chenn Q. , Ma Shilei , Moss Robert , Fisher Mark 
Published: February 2021

Abstract
Accurate measurement of the volumetric flow rate of working liquids is essential for process control, as well as energy consumption evaluation. Electromagnetic flowmeters have gained popularity in applications where low pressure drop and low maintenance are required. Dwyer Instruments, Inc., recently developed an adjustable insertion electromagnetic flowmeter (IEF) featuring accurate and reliable measurement. However, an unexpected and non-repeatable behavior in the K-factor was observed during the calibration process. The K-factor is the coefficient that is used to convert the measured electric potential to the flow velocity in pipes and the non-repeatable behavior imposes challenges for precise measurement.
A one-way coupled magnetohydrodynamics model was developed to reduce the effort and time of on-site troubleshooting and optimization. By modeling the measurement process, the transition of flow regimes and the regeneration of boundary layer on the electrode surface were identified as the causes to the non-repeatable issue. Then, a series of parametric studies were performed to provide reliable solutions. A new design with further embedded electrodes was recommended. The field test showed great repeatability by using the new design and the non-repeatable issue was completely resolved. The improvement in the IEF design was implemented in production in less than one week and it reduced the calibration time by 50%.
Numerical Analysis of a T-Type Electrokinetic Micromixer With Heterogeneous Zeta Potentials and Viscoelectric Effects
Authors: Escandón Juan P. , Torres David A. 
Published: February 2021

Abstract
This paper presents the 2-D numerical solution of the flow and concentration field of an electrokinetic T-type micromixer, under heterogeneous zeta potentials modulated via sinusoidal functions and interfacial viscoelectric effects. Here, the viscoelectric effects appear to modify the fluid viscosity due to the high voltages within the electric double layer. The mathematical model is based on the Poisson-Boltzmann, mass conservation, momentum, and species concentration equations. In the steady-state analysis, two electrolytes with known ionic concentration and an imposed velocity profile are considered at the inlet of the micromixer. The results demonstrate that by using heterogeneous zeta potentials, at the mixer walls, generated flow recirculations along the mixer channel, promoting the rise in mixing efficiency; however, for high zeta potential values, this is counteracted by the viscoelectric effects. The present investigation shows how the viscoelectric condition deteriorates the mixing performance and how with the correct selection of modulated zeta potential parameters as the wave number, and the phase angle can improve it. Therefore, the performance of the mixer studied here should be considered for the design of microfluidic devices in the future.
Effects of Defects on Nanoporous Graphene and MoS2
Authors: Oviroh Peter Ozaveshe , Mohlala Lesego M. , Jen Tien-Chien 
Published: February 2021

Abstract
Nanoporous 2D materials such as grapheme and MoS2 promises better filtrations in water channels. However certain parameters that affects these materials for effective deployment need to be studied. In this paper, molecular dynamics (MD) simulation was performed to study the effects of defects that could increase the prospect of tuning the efficiency of the materials in the transportation, catalysis and mechanical reaction efficiency. Consideration of the interfaces between them could lead to improved functionalities of the materials. This paper systematically compares MoS2 and graphene membranes to highlight specific features and benefits. the Young’s modulus of the pristine monolayer MoS2 was calculated to be 447GPa while that of the defective MoS2 was found to be in the range of (314–374) GPa. The Young’s Modulus for Graphene was 783.2 GPa. The relative variation of the Young’s modulus on MoS2 is in the range (13–35) % while that of graphene is (13–21) %. From the results obtained, the maximum pressure that the MoS2 can withstand depends not just on the spacing and size of the nanopores, but also on the area of the defects in the membrane. These findings could help build and proliferate tunable filtration nanodevices and other applications.
Zimmer Frame Use and Back Strain Analysis Using a Finite Element Model
Authors: Harwood Sydney , Saboori Parisa 
Published: February 2021

Abstract
The current walking frame used by the elderly has several design issues that can cause long term health problems. One of these problems is the development of chronic pain in the lower back. The design of the current walking frame promotes a slumping posture that causes a curvature in the spine. This curvature results in a large strain in the lower back muscles, specifically the erector spinae. The goal of this research was to design a new walking frame that would be more structurally sound and more practical to use than the present walking frame design.
In this study, two literature searches were performed. The first was to explore how aging effects the ability to walk. The second involved studying all of the existing walking devices and analyzing their design strengths and weaknesses. As a result of these studies, three new preliminary walking frame designs were considered that promoted better posture when used, and provided more support than does the present walking frame design. These new designs were considered and tested using a finite element analysis (FEA).
From this FEA, it was determined that the new walking frame design resulted in less stress in the lower back than does the present walking frame design. It was therefore concluded that the new model has the potential to decease chronic back pain.