bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification and Analysis of the Biomechanical Parameters Used for the Assessment of Normal and Pathological Gait: A Literature Review
Authors: Arellano-González Juan C. , Medellín-Castillo Hugo I. , Cervantes-Sánchez J. Jesús 
Published: January 2020

Abstract
The analysis of human gait represents a valuable tool for an early and timely identification of diseases and pathologies, as well as to follow up treatments and rehabilitation programs. However, although several research works in the literature have addressed the assessment of human gait as a diagnostic tool, few works have focused on the biomechanical parameters and metrics needed for such practice. This work presents the results of an investigation carried out to identify and analyze the biomechanical parameters used in the literature to assess the human walking, both pathological and normal. For this purpose, a literature review was conducted to detect and analyze the biomechanical parameters. A classification of these parameters based on the application area is proposed and comprises clinical, sport and exploration. These parameters are also classified according to the origin of the problem into musculoskeletal, neurological and circulatory. The biomechanical parameters identified are analyzed and discussed using set theory. The results indicate that the analysis of the spatiotemporal parameters of the gait allows a detailed and economic study of this mode of locomotion. The most used gait parameters are: step length, stride length, step width, gait speed, gait phases, cadence, swing time and stance time. On the other hand, the study of gait in the clinical area makes use of nearly all the gait parameters reported in the literature, i.e. spatial, temporal, angular, force and other specific parameters according to the type of pathology being analyzed.
An Air Suspension System With Adjustable Height, Damping and Stiffness Using No Viscous Dampers
Authors: Kashani Reza 
Published: January 2020

Abstract
Air suspension is gaining more and more popularity with both the auto industry and drivers. Traditionally the height adjustability aspect of air suspension systems has been their main attracting attribute. More recently, resolving the classic conflict of combining comfortable ride with sport handling in a single suspension setup has become the main attraction of air suspension.
An air suspension system has been developed which in addition to height adjustment, can adjust its damping and stiffness in real time with using neither viscous dampers nor any additional actuators. This is done by real-time adjustment air flow to and from the air springs using proportional valves. Measured relative displacement and acceleration as well as estimated velocity of the sprung mass with respect to unspring mass at each corner are fedback, thru their corresponding gains, to create the control signal that adjusts the proportional valve with the goal of controlling the height, stiffness, and damping at that corner.
In a numerical study followed by laboratory testing, the effectiveness of the proposed air suspension system in terms of its ability to vary the damping and stiffness as well as the height of the suspension system is demonstrated.
Performance Analysis and Parametric Studies of Nose Landing Gear Shimmy Dampers
Authors: Rahmani Mohsen , Behdinan Kamran 
Published: January 2020

Abstract
Self-induced mechanical oscillation of nose landing gears designated as shimmy is a major safety challenge for aircrafts. The rotational-lateral shimmy vibrations can occur during takeoff, taxiing, and landing and needs to be sufficiently controlled to avoid escalation and catastrophic failure of the landing gear system. Existing solutions for shimmy problem are largely passive control strategies known as shimmy dampers. Despite numerous studies on the source of shimmy and its trends, investigations on the design and performance analysis of shimmy dampers are scarce. From a design perspective, it is crucial to quantify the effective stiffness and damping supplied by the shimmy damper to the system in different operation states. Furthermore, the sensitivity of the damper performance to its design parameters needs to be thoroughly investigated in order to optimize the design for a particular aircraft. In this study, core relationships for three shimmy dampers are presented and used to perform sensitivity studies. These dampers are concepts by Boeing, Collins Aerospace (formerly UTAS), and a new one designated as the Symmetric Torque Link Damper (STLD). The influence of design parameters on the dampers’ performance is studied and observed trends are discussed in the light of inherent trade-offs. Subsequently, a nonlinear Multibody Dynamic model of the landing gear is utilized to obtain sample time histories of oscillations for each shimmy damper in order to highlight the performance differences and to demonstrate the influence of design parameters. Directions for designing future shimmy dampers and recommendations for optimizing them are offered.
Estimated Fluid Force and Damping Characteristics of a Thin Film Damper Comparison Between Closed-Form Solutions and Numerical Analysis
Authors: Cook Jason T. 
Published: January 2020

Abstract
Analytical solutions of thin film dampers are useful for determining critical speeds and stability of rotor systems. Most thin film dampers in use are of short axial length, and closed-form solutions to the Reynolds equations exist for estimating pressure, forces, and damping for these types of dampers. This article compares the fluid film forces and damping estimated by the short film bearing model form of the Reynolds equations to the calculated forces and damping of a transient computational fluid dynamic simulation. For this comparison, the fluid was assumed to be incompressible, laminar, and isoviscous. The fluid film forces and damping are calculated from integrating the pressure distribution over the surface of the damper due to small amplitude motions about a steady state static off-center circular orbit. In this case, no cavitation is assumed, and the journal has no angular velocity, so direct stiffness cannot be calculated from the closed-form solution. Radial clearance, journal length, and journal eccentricity have a significant effect on fluid force and damping within a thin film damper. Fluid density does not affect fluid force or damping substantially, while fluid viscosity does. Both the closed-form solutions and computational fluid dynamics simulation compare well with each other and reflect these trends.
Cryogenic Material Properties of Polycaprolactone
Authors: Sagar Amrit , Nehme Christopher , Saigal Anil , James Thomas P. 
Published: January 2020

Abstract
In pursuit of research to create a synthetic tissue scaffold by a micropunching process, material properties of Polycaprolactone (PCL) in liquid nitrogen were determined experimentally. Specimens were prepared using injection molding and tested under compression to determine the stress-strain relationship of PCL below its glass transition temperature. Cryogenic conditions were maintained by keeping the PCL specimens submerged in liquid nitrogen throughout the loading cycle. Specimens of two different aspect ratios were used for testing. Yield Strength, Strength Coefficient, and Strain Hardening Exponent were determined for different specimen aspect ratios and extrapolated for the case with zero diameter to length ratio. Material properties were also determined at room temperature and compared against results available in the literature. Results demonstrate that PCL behaves in a brittle manner at cryogenic temperatures with more than ten times increase in Young’s modulus from its value at room temperature. The results were used to predict punching forces for the design of microscale hole punching dies and for validation of a microscale hole punching model that was created with a commercially available finite element software package, DEFORM 3D. The three parameters Yield Strength, Strength Coefficient, and Strain Hardening Exponent used in Ludwik’s equation to model flow stress of PCL in DEFORM 3D were determined to be 94.8 MPa, 210 MPa, and 0.54, respectively.
Optimum Synthesis of Rigid Mechanisms Using a Dynamic Ant-Search Method With Sensitivity Analysis
Authors: Diab Nadim , Itani Omar , Smaili Ahmad 
Published: January 2020

Abstract
Four-bar linkages are commonly used mechanisms in various mechanical systems and components. Several techniques for optimum synthesis of planar mechanisms have been suggested in literature such as the Genetic, Tabu, Simulated Annealing, Swarm-Based and many other algorithms. This paper covers optimization of four-bar mechanisms with path generation tasks using a Dynamic Ant Search (DAS) algorithm. Unlike the Modified Ant Search (MAS) technique where ants unanimously moved between the exploration and exploitation phases, in the proposed algorithm, each ant is free to travel between the two aforementioned phases independent of other ants and as governed by its own pheromone intensity level. Moreover, sensitivity analysis is conducted on the design parameters to determine their corresponding neighborhood search boundaries and thus improve the search while in the exploitation mode. These implemented changes demonstrated a remarkable impact on the optimum synthesis of mechanisms for path generation tasks. A briefing of the MAS based algorithm is first presented after which the proposed modified optimization technique and its implementation on four-bar mechanisms are furnished. Finally, three case studies are conducted to evaluate the efficiency and robustness of the proposed methodology where the performances of the obtained optimum designs are benchmarked with those previously reported in literature.
A Process Plant for Producing Rocket Fuel From Lunar Ice
Authors: Carrato Peter , Demitz Jack , Mueller Rob , Gulen John , Benz August 
Published: January 2020

Abstract
One of, if not the most, valuable resources on the Moon is ice. Since the late 1990’s evidence has been accumulating that supports the presence of water ice at both the north and south lunar poles. Although consumption of water is critical to sustaining human life, water can also serve as a feedstock to produce rocket fuel. Water may be broken down into hydrogen and oxygen which, when liquified, serves as a propellant for space travel. This paper investigates the process and energy demand for producing liquid hydrogen and oxygen from lunar ice. A preliminary flow sheet and discussion of unit operations for a lunar rocket fuel plant are provided. Sources of energy on the Moon, as well as design of structures, systems and components for the facility are considered.
Nanoparticles EOR Aluminum Oxide (Al2O3) Used As a Spontaneous Imbibition Test for Sandstone Core
Authors: Samba Mohammed A. , Hassan Hafsa A. , Munayr Mahjouba S. , Yusef Moataz , Eschweido Abdelkareem , Burkan Hamed , Elsharafi Mahmoud O. 
Published: January 2020

Abstract
There are three types of oil production energy operations, primary recovery, secondary recovery and enhanced oil recovery (EOR). EOR consider as the last period for production operations. Where the EOR classify into many types such as thermal injection, gas injection, microbial EOR and chemical flooding.
Chemical flooding classified into many types such as polymer, surfactant, alkaline and nanoparticles (NP). NP can be classified into many types such as Iron Oxide (Fe2O3), Aluminum Oxide (Al2O3) and Magnesium Oxide (MgO) etc. In this study NP Aluminum oxide (Al2O3) were used to enhance the oil recovery.
The main objective of this study is to use the Nanoparticles EOR (Al2O3) and know it is effect on increasing the extraction of oil from cores. The big motivation of using Al2O3 that it is easy to extract it from raw clay. However, the raw clay is available in Libya and using it will be more economic than using other method of chemical EOR.
Nanoparticles EOR Aluminum oxide (Al2O3) used as a spontaneous imbibition test for sandstone core samples after saturated by crude oil. A spontaneous imbibition test consisting of two scenarios of nanoparticle solution (Al2O3) with change temperature and compared with one scenario of distilled water. The spontaneous imbibition test was performed in this study at room temperature to oven temperature (30C°, 40C°, 50C°, 60C°, 70C°).
The results shown that the oil recovery increases with the increase of the concentration of nanoparticle (Al2O3) and increase the temperature. The higher oil recovery was 76.04% at NP (Al2O3) concentration 1%. Finally, oil swelling and adsorption (NP (Al2O3) with oil drops) have been noticed during the extraction of oil. Thus, the gravity force will be higher than the capillary force.
Steam Generation for EHOR Using PTC System Modeled in SAM
Authors: Gharbia Yousef , Fayed Mohamed , Anany Mohammed 
Published: January 2020

Abstract
Kuwait’s oil reserves include approximately 13 bn barrels of heavy oil, primarily located in the northern region of the country. The Lower Fars (LF) heavy oil development project aims to extract heavy oil from the Ratqa oil field. The US$7 bn project is being developed in phases, with the first phase expected to start in 2019 with a production rate of 60,000 Barrel of Oil Per Day (BOPD). This amount is planned to ramp up to 270,000 BOPD by 2030. The steam required for the Enhanced Heavy Oil Recovery (EHOR) process can be either generated by using conventional fuels or renewable energy resources, such as solar energy. The amount of steam required to recover a certain quantity of heavy oil depends on the value of Steam to Oil Ratio (SOR).
The aim of this work was to determine the specifications of a parabolic trough collector field required to produce steam with the right properties to recover 270,000 BOPD from Lower Fars reservoir. The Industrial Process Heat (IPH) model of the System Advisor Model (SAM) software, developed by the National Renewable Energy Laboratory (NREL), was used for this purpose. The capital cost and the running cost of the project, as well as the Levelized Cost of Heat (LCOH), were also determined. The simulation was implemented on EuroTrough ET150 trough collectors and Schott PTR 70 receiving tubes. Different plant designs with different types of heat transfer fluids (HTF) including Therminol VP-1, Therminol 59, Therminol 66, Dowtherm Q, Dowtherm RP, and Caloria HT43 have been investigated.
Forming Technology and Microstructure Distribution of Automobile Oil Pump Shaft by Extruded Cross Wedge Rolling
Authors: Shu Xue-Dao , Chen Tai-Zhu , Chang Ying , Zhu Ying , Gong Wen-Wei 
Published: January 2020

Abstract
In order to improve the material utilization ratio of automobile oil pump shaft, the extrusion wedge cross rolling process was developed to form automobile oil pump shaft, the results show that the volume of the blank head produced by extrusion cross wedge rolling is reduced by about 75% compared with that produced by traditional cross wedge rolling, and the material utilization ratio can be increased to about 95%. The microstructure distribution of automobile oil pump shaft formed by this process was studied systematically by fem simulation and experiment, get the forming process can make the grain size of oil pump shaft rolling parts refine continuously, and finally obtain fine and uniform grain structure. The average grain size measured by the experiment is in good agreement with the simulation results. The research results lay a theoretical foundation for reducing oil pump cost and improving life.
Analysis of Cornering Strength of Steel Wheels Including the Effects of Disc and Rim Interference Assembly
Authors: Dang Bin , Shan Yingchun , Liu Xiandong , Wang Xiaoran , Zhang Yue , Zeng Xianyu 
Published: January 2020

Abstract
The cornering fatigue test of commercial vehicle steel wheel is modeled and simulated by finite element method in this paper. The influence of interference stress between wheel disc and rim on the simulation results is analyzed. The interference stress is taken as predefined fields to superimpose with the stress generated by the bending load. Then the influence of two different superposition methods defining the interference stress as the average stress and the predefined fields on the stress in dangerous area of the wheel is compared. The results show that the interference stress has a significant effect on the stress state of the wheel and increases the amplitude of symmetric cyclic stress, which directly affects the prediction of fatigue life of the wheel. Therefore, the interference stress must be taken into consideration in the simulation analysis of cornering fatigue test. The influence of different interference stress superposition methods on the stress variation in the dangerous area is obviously different. The method which superimposes interference stress as predefined fields with the stress generated by the bending load is more consistent with the actual assembling and loading process of the wheel. Therefore, this paper provides a reasonable method for the simulation of cornering fatigue test, which can provide more accurate stress simulation results for the prediction of cornering fatigue life of the wheel.
A Study of Fast Charging of Li-Ion Battery With Pulsed Current
Authors: Liu Yu , Xu Meng , Xu Zhibang , Wang Xia 
Published: January 2020

Abstract
To fast charge lithium ion batteries while achieving higher capacity and limiting temperature rise, a constant current plus pulse current (CCPC) charging protocol is proposed. Parametric study for the CCPC design parameters including the current level, cut-off voltage, and pulse duration is performed experimentally. Taguchi method is adopted to search an optimal charging pattern. Experimental results show that the pulse charge current has the greatest effect on the charging time and temperature rise, while the pulse discharge current has the least effect on both. The optimal pattern from the Taguchi method is able to charge the cylindrical cell 15.6% faster than the traditional constant current constant voltage (CCCV) charging protocol. An electrochemical and thermal coupled model is developed to reveal the working principle of the CCPC. The modeling results show that the CCPC charging protocol reduces the concentration polarization with more uniform lithium ion distribution than the CCCV, thus accelerating the charging process.
Effects of Braking Pressure Distribution on Temperature Field and Stress Field During Braking
Authors: Zeng Xianyu , Liu Yu , Liu Xiandong , Shan Yingchun , Zhang Yue , Wang Xiaoran 
Published: January 2020

Abstract
The braking performance of the vehicle directly affects the driving safety. Because of the different number of brake pistons and the wear of the brake pads, the distribution of braking pressure will be uneven, which will affect the distribution of temperature field and stress field during braking, then affect the thermal fatigue life of brake discs. Therefore, in this paper, the static tensile and compressive tests of gray cast iron HT200 samples cut from vehicle brake discs are carried out at −25°C, room temperature (25°C) and 500°C, and the stress-strain curves are analyzed to obtain mechanical properties such as strength limit, elastic modulus and so on at the temperature. Based on these parameters, the finite element software ABAQUS is used to simulate the single emergency braking condition. The thermal-structural coupling simulation of brake disc is carried out to study the influences of uneven brake pressure distribution on the temperature and stress fields of brake disc, which lays a foundation for the thermal fatigue life evaluation of brake disc.
Design and Analysis of Epoxy Based Cable Terminations for Marine Cables
Authors: Prakash Raghu V. , Vibhu Padmanabhan G. 
Published: January 2020

Abstract
Synthetic fibers like Kevlar and Vectran are used as load carrying members in Electro-mechanical cables for marine applications. These cables have high strength, high modulus and very low water absorption rate which make them suitable materials for marine applications. The flexible electromechanical cables carry tensile load and electrical power along with data signals. Terminations are used to connect these cables to another cable or terminal. An efficient termination will ensure a load carrying capacity that is almost equal to the breaking load of the strength member of the cable. The presence of stress concentrators due to large diametrical difference between termination body and the braided fiber diameter as well as degradation in material properties reduces the strength and results in failure.
This study focuses on a chemical potting method of termination, where an epoxy compound is poured into a socket containing the Vectran™ synthetic fibers. The basic design of epoxy based termination, which has a cylindrical outer shell which secures the epoxy-fiber matrix, was selected for this study. The outer shell has two cylindrical inner surfaces of different diameters connected by a tapered region. Material property for static and fatigue loading was evaluated. Finite element analysis was carried out to understand the maximum stress profile developed in the termination and to improve the design. Baseline data on mechanical properties obtained from experiments was used as input in FE analysis. Results of the finite element analysis suggest a reasonable correlation with experiments.
Composite Overwrapped Pipe Burst Test: Modeling and Experimentation
Authors: Littlefield Andrew , Smith Lucas , Macri Michael , Root Joshua 
Published: January 2020

Abstract
With the emphasis on lightweighting, composites are being turned to help reduce weight while still maintaining strength and stiffness. However, composites tend to be linear elastic to failure so there is often no warning of failure unlike in metallic components. For this research, a pipe section was fabricated from an Inconel 718 liner with a carbon composite overwrap. The pipe was then subjected to increasing internal pressure until failure. The results from this experiment were used to assist in the creation and validation of a finite element model of the experiment. The model makes use of advanced numerical techniques to predict when failure will occur. This paper will present the fabrication, testing and modeling of this effort.