bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Flexible Tactile Sensor Using Area-Arrayed Bundle Structures of Multi-Walled Carbon Nanotubes
Authors: Osada Ryusaku , Suzuki Ken
Published: January 2019

In recent years, surgical assisting robots and nursing care robots are being introduced to medical and nursing fields due to the rapid increase of the aging society. In order to assure the safety and reliability of these robots, a highly sensitive tactile sensor is necessary to detect the state of contact between these robots and human body. The target specifications of this sensor are spatial resolution of less than 1 mm, and the pressure sensitivity of less than 10 kPa. Since the tactile sensor is expected to be attached on the tip of a surgical assisting robot or the arm of a nursing care robot, it should be small and flexible and highly sensitive to contact pressure.

In this study, high quality MWCNT (Multi-Wall Carbon Nanotube) has been synthesized to develop two types of tactile sensors which consisted of a MWCNT film and the area-arrayed MWCNT bundles. Thermal CVD (Chemical Vapor Deposition) method was applied to the growth of MWCNT and PDMS (Polydimethylsiloxane) was used for a flexible substrate. It was found that MWCNT bundles showed elastic deformation in the compressive strain range from 0% to 60%. The PDMS substrate showed elastic deformation under the application of bending strain of about 20%. In addition, it was confirmed that the detecting resolution of the force was lower than 1 mN, and the obtained gauge factor of the developed sensor was about 3.5.
Area-Arrayed Graphene Nano-Ribbon-Base Strain Sensor
Authors: Nakagawa Ryohei , Wang Zhi , Suzuki Ken
Published: January 2019

Health monitoring devices using a strain sensor, which shows high sensitivity and large deformability, are strongly demanded due to further aging of society with fewer children. Conventional strain sensors, such as metallic strain gauges and semiconductive strain sensors, however, aren’t applicable to health monitoring because of their low sensitivity and deformability. In this study, fundamental design of area-arrayed graphene nano-ribbon (GNR) strain senor was proposed in order to fabricate next-generation strain sensor. The sensor was consisted of two sections, which are stress concentration section and stress detecting section. This structure can take full advantage of GNR’s properties. Moreover, high quality GNR fabrication process, which is one of the important process in the sensor, was developed by applying CVD (Chemical Vapor Deposition) method. Top-down approach was applied to fabricate the GNR. At first, in order to synthesize a high-quality graphene sheet, acetylene-based LPCVD (low pressure chemical vapor deposition) using a closed Cu foil was employed. After that, graphene was transferred silicon substrate and the quality was evaluated. The high quality graphene was transferred on the soft PDMS substrate and metallic electrodes were fabricated by applying MEMS technology. Area-arrayed fine pin structure was fabricated by using hard PDMS as a stress-concentration section. Finally, both sections were integrated to form a highly sensitive and large deformable pressure sensor. The strain sensitivity of the GNR-base sensor was also evaluated.
Crystallinity-Induced Variation of the Electronic Characteristics of Electroplated Gold Thin Films
Authors: Nakoshi Yutaro , Miura Hideo
Published: January 2019

Electroplated gold thin films have been used for micro bumps in flip chip packing structures. However, it has been reported that physical properties and micro texture of the electroplated thin films vary drastically comparing with those of conventional bulk material, depending on their electroplating process. In addition, since one bump is going to consist of a few grains or a single grain due to the miniaturization of the 3D structures, it shows strong anisotropic mechanical properties because a face-centered cubic crystal essentially has strong anisotropy of physical properties. Therefore, there should be the wide distribution of characteristics of the micro bumps depending on their micro structure and the variation of the crystallinity of grains and grain boundaries enlarges the width of the distributions of various properties. Particularly, it was found that the long-term reliability of micro bumps and interconnections is degraded drastically by porous grain boundaries with a lot of defects because of the acceleration of atomic diffusion along the porous grain boundaries under the application of high current density (electromigration) and high mechanical stress (stress-induced migration).

In this study, the effect of crystallinity, in other words, the order of atom arrangement of grain boundaries in electroplated gold thin films on the EM resistance was investigated experimentally. The crystallinity of the gold thin films was varied drastically by changing the under-layer material used for electroplating; such as Cr (30 nm) / Pt (50 nm)/ Au (200 nm) and Ti (50 nm) / Au (100 nm). The mechanical properties of the electroplated gold thin films were measured by using a nano-indentation test. Also, the micro textures such as crystallinity and crystallographic orientation of gold thin films were investigated by EBSD (Electron Back-Scatter Diffraction) and XRD (X-Ray Diffraction). It was clarified that the crystallinity of the electroplated gold thin films changed drastically depending on the crystallinity of the under-layer materials and heat treatment conditions after electroplating. This variation of the crystallinity should have caused the wide variation of mechanical properties of the electroplated gold films. Therefore, it is very important to control the crystallinity of the under layer used for electroplating in order to control the mechanical properties and reliability of the electroplated gold thin films.
Numerical Analysis on the Hydraulic Performance of the Auxiliary Impeller in Large Capacity Canned-Motor Pump
Authors: Wang Shengde , Yao Zhenqiang , Shen Hong , Luo Guohu
Published: January 2019

A special structure named auxiliary impeller is designed in the large capacity canned-motor pump to improve the performance of inner loop cooling system. The structure is set on the rotor shaft using the center hole as the inlet conduit and four holes perpendicular to the center hole as the blade channels. The auxiliary impeller is driven by the rotor shaft of the motor and functions as a centrifugal pump. The inner coolant circulates in the clearance of the pump under the effect of centrifugal force generated by the impeller. In this paper, the output pressure of the auxiliary impeller at different rotational speeds is investigated by numerical simulation. Three geometric parameters including the diameter of the inlet channel, the diameter of the blade flow channel, and the rotating radius are considered in the research. The pressure drop curves of the auxiliary impeller at different rotational speeds are drawn and a mathematical model is given to interpret it. The results show that both the three geometric parameters have influence on the output performance of the auxiliary impeller, and the diameter of the blade channel and the length of the rotating radius are the primary factors.
Numerical Study of Nanofluid-Based Solar Collector for Humidification-Dehumidification (HDH) Desalination
Authors: Garg Kapil , Khullar Vikrant , Das Sarit K. , Tyagi Himanshu
Published: January 2019

Humidification-dehumidification (HDH) desalination technology is one such technology (based on thermal desalination technology) which has been found to be ideal for small scale water productions (1–100 m3/day). It requires less maintenance and can be combined with renewable energy sources such as solar or geothermal due to lower temperature operation. In this paper, nanofluid-based direct absorption solar collector (DASC) has been coupled with the one of the versions of HDH desalination system (closed air open water - CAOW) with the help of a counter-flow heat exchanger. These collectors (DASCs) have high thermal efficiency (10% higher) as compared to conventional surface absorption based collectors. Numerical model is prepared for a closed air open water HDH system, working together with a direct absorption solar collector. The aim of the present study is to evaluate the thermal performance of the system in terms of gained output ratio (GOR) against the various influencing parameters related to the solar collector such as, height (H) and length (L) of the collector, nanoparticle volume fraction (fv), and incident solar radiation on the collector (q) and the effect of the aforementioned parameters on the collector outlet temperature (Tout) have also been analyzed in detail. Solar weighted absorptivity (Sab) for different nanofluids has also been calculated which helps in choosing the suitable nanoparticle material for preparing the nanofluid. The gained output ratio of the proposed system was found to be around 16% higher, compared to conventional CAOW-HDH desalination systems under certain operating conditions. Finally, the model proposed in this study has been validated with the data available in literature.
Effect of Pre-Bending on Formability of DQ Steel and Al 5182
Authors: Memon Shabbir , Mohammed Obaidur Rahman , Lankarani Hamid M.
Published: January 2019

The effect of the pre-bending operation on ductility can be significant in determining the limit strains of the final product. The strain path experienced in straight tube bulging is significantly different from that of elbow (tube with pre-bending), leading to a reduction in bulge height. The Tube bending introduces strain gradient both along the tube and across the tube. In this work the effect of pre-bending on limit strains during tube bulging process is predicted — and the results are compared to the limit strains of bulged tubes without pre-bending. The Finite Element (FE) model of the bending operation is developed which utilizes an explicit dynamic finite element formulation. The PAMSTAMP 2G code is used to perform the numerical pre-bend (and bulging) simulations.

Tension side of bend tube axial strain is found to be positive and hoop strain as negative and vice versa along the compression side. During the bulging, the neck usually develops perpendicular to major strain direction. During bend tube bulge test with fixed expansion and axial feed expansion of bend tubes, in both cases the crack is found to be in the axial direction.
Wood - Concrete Composite for Thermally Insulated Building Construction Material
Authors: Gupta Anuj , Thakur Harishchandra
Published: January 2019

One of the important parameters in the reduction of greenhouse gas emission can be considered as the energy efficiency of the building. The building sector is constantly innovating in its use of materials with regards to sustainability. There is a need to use cost-effective, environmentally friendly materials and technologies which lessen the impact of a construction in terms of its use of non-renewable resources and energy consumption. For the reduction in energy consumption, thermally insulating materials can be installed inside the building envelope. It prevents heat loss and provides thermal comfort for the occupants. The introduction of the organic waste materials for thermal insulation is recent and little is known for their environmental effect in comparison with the conventional materials. Present study consists of experimental analysis to investigate the composition of wood powder and ash brick as a brick. Different modifications have been performed to determine the best methodology for the change in standard ash brick. The study has been concluded with the help of heat transmission factor and compressive strength.
Fluid Impact Under Various Tapping Conditions for Biomedical Application (Shirodhara)
Authors: Meenraj Swathika , Rao Chebolu Lakshmana , Venkatesh Balasubramanian
Published: January 2019

Shirodhara is an ayurveda therapy treating subjects for stress (depression/anxiety/hypertension) insomnia, headache and several kinds of psychosis. When there is a fluid impact on a solid surface, a transient impact will be developed at the interface in short time duration as vibration on forehead. The fluid impact of the liquid falling from the beaker at controlled flow rate is measured using an integrated circuit piezoelectric (ICP) force sensor for various tapping condition. The time-dependent response of the sensor is acquired using data acquisition system which is connected to the computer. The force is determined by measuring the voltage output from the piezoelectric force sensor. The impact experiment is done for single droplet, intermittent flow of drops and continuous flow of liquid falling from a fixed height of 7.5 cm. From the results, we observe the impact force for each fluid have a subtle variation depending on the falling condition and impact velocity of the fluid falling from a height.
Demonstration of an Industrial Framework for an Implementation of a Process Digital Twin
Authors: Eyre Jonathan M. , Dodd Tony J. , Freeman Chris , Lanyon-Hogg Richard , Lockwood Aiden J. , Scott Rab W.
Published: January 2019

Digital twins have received a large amount of exposure around what they can offer to industry generating lots of noise, however there are few demonstrations utilizing published architectural frameworks. This has been addressed by investigating industrial publications and reports on what is the minimum essential requirements to form a digital twin and additional desirable features. From this, a generic industrial architectural framework of a digital twin has been established to utilize real-time information from a physical asset forming a monitoring digital twin. This has been expanded to incorporate a Discrete Event Simulation (DES) to form a process digital twin utilizing structured information about the process. The framework, including the DES extension, has been validated on a reconfigurable fixture utilizing an established process that has been modelled using Siemens Plant Simulation. This result forms the start of a feedback loop presenting additional value transforming a monitoring digital twin into a process digital twin. This provides a solid foundation for discussion within the industrial community about defining the core functionality required for digital twins.
Study on Turning of Non-Axisymmetric Three-Dimensional Curved Surfaces
Authors: Mori Taichi , Morimoto Yoshitaka , Hayashi Akio , Kaneko Yoshiyuki , Suzuki Naohiko , Hirono Ryo
Published: January 2019

Conventional machining of complex parts having three-dimensional curved surfaces is performed in two steps using a five-axis machining center and a grinding machine. There is a problem with productivity. Therefore, we developed a CNC lathe to cope with high-speed machining. The newly developed CNC lathe has four axes (X1, X2, Z, C). In this machining, the tool on the X axis follows the curved surface synchronously with the rotation angle of the spindle. This cutting method enables machining of the three-dimensional curved surface. By adopting a linear motor for the X axis, high-speed reciprocal motion of the tool is realized, and the machining time has been reduced to approximately 1/30, as compared with the conventional milling process. In this operation, since high-response motion is required for the tool positioning, a certain profile error remains even if repeated control is applied using the linear scale.

In the present study, for the purpose of improving the contour accuracy of a three-dimensional curved surface, we report the result of compensation between the profile measurement method of workpiece and the desired profile accuracy. After machining a three-dimensional curved surface by the developed CNC lathe, a line laser displacement sensor is used to measure the workpiece profile on the machine without removing the workpiece. The position of the machining program is measured by synchronizing the controller of the CNC lathe and the line laser displacement gauge. In addition, the desired profile accuracy is improved by compensating for the error between the desired profile accuracy and the measurement result.
CFD Analysis of Direct Contact Condensation (DCC) of Subsonic Steam Jets in a Cross-Flow of Water Using a Two-Fluid Model
Authors: Narayanan Jayachandran K. , Roy Arnab , Ghosh Parthasarathi
Published: January 2019

Direct contact condensation occurs when a vapor comes in contact with the liquid of the same fluid and is accompanied by very high heat transfer coefficients compared to the conventional heat exchanging processes. Many researchers have investigated the direct contact condensation of steam jets in a pool of subcooled water. In the last decade, the potential of flowing liquid as an enhanced heat transfer medium in comparison with the stationary pool of liquid was explored by various researchers. Also, in some configurations of staged combustion cycle based rocket engine, the oxygen-rich gas is injected into flowing liquid oxygen to improve the heat transfer characteristics. Hence, there is a need to investigate the direct contact condensation of vapor jets in a cross flow of liquid. A two-fluid particle based multiphase formulation with thermal phase change model has been implemented in the present investigation to capture the direct contact condensation phenomena. The data obtained from numerical simulations are validated with the experimental results of Clerx et al., [1]. Further, studies on plume shapes, interfacial area and pressure amplitudes are reported.
Spray Performance of Alternative Jet Fuel Based Nanofuels at High-Ambient Conditions
Authors: Soltan Mohamed , Al Abdulla Buthaina , Al Dosari AlReem , Kannaiyan Kumaran , Sadr Reza
Published: January 2019

Dispersion of nanoparticles in pure fuels alters their key fuel physical properties, which could affect their atomization process, and in turn, their combustion and emission characteristics in a combustion chamber. Therefore, it is essential to have a thorough knowledge of the atomization characteristics of nanofuels (nanoparticles dispersed in pure fuels) to better understand their latter processes. This serves as the motivation for the present work, which attempts to gain a good understanding of the atomization process of the alternative, gas-to-liquid (GTL), jet fuel based nanofuels. The macroscopic spray characteristics such as spray cone angle, liquid sheet breakup, and liquid sheet velocity are determined by employing shadowgraph imaging technique. The effect of nanoparticles weight concentration and ambient pressures on the spray characteristics are investigated in a high pressure-high temperature constant volume spray rig. To this end, a pressure swirl nozzle with an exit diameter of 0.8 mm is used to atomize the fuels. The macroscopic spray results demonstrate that the nanoparticles dispersion at low concentrations affect the near nozzle region. The spray liquid sheet breakup distance is reduced by the presence of nanoparticle due to the early onset of disruption in the liquid sheet. Consequently, the liquid sheet velocity in that spray region is higher for nanofuels when compared to that of pure fuels. Also, the ambient pressure has a significant effect on the spray features as reported in the literature.
Research on a Mechanical Model of the Connecting and Sliding Parts in Motion for a Reciprocating Compressor
Authors: Mizobe Yu , Mori Yoshifumi , Saito Takashi
Published: January 2019

To avoid discontinuation during long-term continuous operation in plants, a reliable monitoring system for the state diagnosis is strongly expected. However, occurring troubles of various facilities in a plant aren’t simple. We proposed a sophisticated estimation method to diagnose the state for reciprocating compressors. Our monitoring system uses both the measuring data in the factory and the analytical results based on the mathematical model, which can express the dynamic behavior about the reciprocating compressor. The mathematical model has multi degrees of freedom and the model parameters are identified to estimate the state change. To realize the reliable monitoring, we have to establish estimation and diagnosis method for any change of the operation state.

In this paper, we discuss estimation method of the rigidity in connecting and sliding portions by using the measuring data during operation of the reciprocating compressor in case of changing a connecting parts. We identified parameters of spring constant, by which one can be obtained the frequencies of eigenvalue analysis correspond to some natural frequencies determined based on an optimal problem. Moreover, we analyzed frequency responses of the model using the identified parameters and compared the frequency responses of the model with those of experimental results.
A Study on Sampling Strategies to Determine the Variability of Parametric History-Based 3D CAD Models
Authors: Contero Manuel , Naya Ferran , Pérez-López David , Company Pedro , Camba Jorge D.
Published: January 2019

Design reusability largely depends on the parametric quality of its associated digital product data. In this regard, the quality of the master model (typically a history-based parametric model) is crucial. However, no quantitative metrics exist that can provide an accurate assessment of parametric complexity and model reusability. In this paper, a set of 370 parametric 3D CAD models of various geometric complexities were analyzed to assess their robustness when undergoing alteration. Three indicators for estimating the modification ability of the model are proposed: Ratio for Exhaustive Modification, Ratio for Selective Exhaustive Modification, and Ratio for Weighted Exhaustive Modification. Correlations between these indicators as well as other geometric complexity metrics are studied. The geometric complexity metrics considered in our study include number of faces, surface area to volume ratio, sphericity, and convexity. Our experimental results with the proposed indicators provide new insights on the quantitative assessment of parametric complexity and support their use as reliable indicators of CAD model reusability.
Mechanical Properties of the Human Elbow Bones Measured by Nanoindentation and Microindentation
Authors: Singh Dilpreet , Pandey Pulak Mohan , Kalyanasundaram Dinesh
Published: January 2019

In this article, the nano and microhardness and the elastic modulus of the human elbow bones (humerus, ulna and radius) were studied. The nano properties were studied using load controlled technique with a load of 20 mN, while the micro properties were studied under 1 N load. A total of nine bone samples from three cadavers of ages between 45 and 55 years were tested. The measurements were carried out on both osteonal and interstitial bone in the longitudinal direction. The nanoindentation results indicated higher values for interstitial bone (hardness: 0.74 ± 0.09 GPa, elastic modulus: 19.05 ± 1.92 GPa) than for osteonal bone (hardness: 0.53 ± 0.05 GPa, elastic modulus: 16.66 ± 1.55 GPa). Consistent results were obtained at a depth of penetration between 1.1 μm to 1.5 μm in nanoindentation. In the case of microindentation, the microhardness and elastic modulus of interstitial bone was found to be 0.65 ± 0.07 GPa and 20.60 ± 2.27 GPa. Whereas for osteonal bone it was observed to be 0.60 ± 0.08 GPa and 14.56 ± 1.42 GPa respectively. The depth of penetration varies between the 8 μm to 11 μm for microindentation studies. In both measurement scales, a noticeable difference was observed between the osteonal and interstitial bone properties. As bone is a hierarchical structure, identifying the mechanical properties at the lamellar level helps in understanding the local mechanical environment of basic elements of the bones and predicting the behavior of the bone due to physiological loading.
A Novel Hybrid Strategy for Multimode Operation Mapping and Feature Extraction on Data-Driven Statistical Fault Detection Methods
Authors: Pinzón Horacio , Audivet Cinthia , Alexander Javier , Torres Melitsa , Consuegra Marlon , Sanjuán Marco E.
Published: January 2019

Fault detection and diagnosis schemes based on data-driven statistical modelling are highly dependent on an accurate and exhaustive feature extraction procedure to deliver a superior performance as a monitoring strategy. Otherwise conducted, a deficient feature extraction procedure leads to a monitoring structure widely deviated from normal operating conditions. If an operating state is not identified as it, an increment in false alarm rate would be evidenced whenever the process shifts towards that condition and the monitoring scheme triggers the abnormal condition warning. On the other hand, if two similar operating conditions could not be individualized i.e. to be identified as a single operating state, a lack of sensitivity for minor — yet typical — deviations would render a monitoring strategy with prominent misdetection rates.

Although Multimode Operational Mapping requires the proper identification of a finite set of normal process states, it is a challenging task especially for large-scale systems. Its complexity derives from a broad universe of monitoring variables, highly interactuating process units integrated over very dynamic network systems, among others. This is the case of natural gas transmission infrastructure, as it deals with variable upstream production rates, diverse consumption trends from customers, internal processes constrains, merged in a stringent operating scheme.

This paper proposes a novel strategy to address the identification and feature extraction of normal conditions on multimode operation systems. The proposed framework uses a segmentation approach based on operator’s knowledge, the Takagi-Sugeno-Kang fuzzy engine and k-means algorithm to characterize the normal operation states of the system. The results show an improvement in the performance of Principal Component Analysis during abnormal conditions detection, in addition an increase on the sensitivity of Hotelling and Q statistics.
Numerical Analysis of a Multi-Species MHD Model for Plasma Layer Control of Re-Entry Vehicles
Authors: Dias Filipe , Páscoa José , Xisto Carlos
Published: January 2019

Several critical aspects control the successful reentry of vehicles on the earth’s atmosphere: continuous communication, GPS signal reception and real-time telemetry. However, there are some common issues that can interfere with the instruments operation, the most typical being the radio blackout, in which the plasma layer frequency modifies the electromagnetic waves in a way that makes communications to and from the spacecraft impossible. So far, there have been several proposed techniques to mitigate radio blackout, one of which is the usage of electromagnetic fields. Previous studies have proven the effectiveness of the usage of an electric and/or magnetic fields to manipulate plasma layers. Experiments on plasma layer manipulation during hypersonic flight regime are extremely costly. Therefore, there has been a continuous interest in the development of cheaper solutions, that can guarantee a reliable degree of accuracy, such as the development of complex multiphysics computational models. These models are becoming increasingly realistic and accurate, as more and more physical aspects can be considered, greatly increasing the accuracy and range of models. However, those models need to be validated with recourse to experimental data. In this paper we propose a model that uses a Low Magnetic Reynolds number, and accounts for five common neutral species: N2, O2, NO, N and O, along with several of their respective reactions: dissociation of molecular nitrogen and oxygen, and exchange. The model chemistry is then validated based on experimental data gathered by several authors.
Modal Damping and Frequency Variations in Nonlinearly Coupled Oscillators With Negative Linear Stiffness Components
Authors: Alhammadi Fatima K. , AL-Shudeifat Mohammad A.
Published: January 2019

A method is applied here to extract the amplitude-dependent modal damping coefficients and frequencies of nonlinearly coupled oscillators with a nonlinear force in which a negative linear stiffness is incorporated. The proposed method can be directly applied into the equations of motion of the original system where the solution is not required to be obtained a priori. The exact nonlinear frequency content in the nonlinear coupling element is employed to obtain an equivalent amplitude-dependent stiffness element using a scaling parameter that preserves the exact frequency content in the original nonlinear element. Therefore, at each amplitude in the nonlinear coupling force, the modal damping coefficients and frequencies are calculated from the eigensolution of the instantaneous amplitude-dependent equivalent system. It is found that the modal damping content is strongly affected by the nonlinear frequency content where the modal damping coefficients become amplitude-dependent quantities. The obtained amplitude-dependent damping coefficients are plotted with respect to the potential energy of the nonlinear coupling force. The method is also applicable with larger degree-of-freedom nonlinear dynamical systems in which negative and non-negative linear stiffness components are incorporated in the nonlinear coupling forces. The amplitude-dependent modal damping matrices of the amplitude-dependent equivalent systems are found to be satisfying all matrix similarity conditions with the linear modal damping matrix of the original system.
Effect of Angular Acceleration and Unbalance Force Orientation on the Backward Whirl in Cracked Rotors
Authors: Alhammadi Fatima K. , AL-Shudeifat Mohammad A. , Shiryayev Oleg
Published: January 2019

Rotors have wide applications in several aerospace and industrial heavy-duty systems. In most of these applications, the rotating system reaches its steady state operational speed after the passage through at least one of its critical rotational speeds. In real-life applications, the probable appearance of a residual slight unbalance in the system could cause an elevation in vibration amplitudes at the critical rotational speeds. Accordingly, propagation of cracks in rotating shafts usually influences the level of these vibration amplitudes during start-up and cost-down operations. For such rotating systems, the critical whirl speeds are usually associated with forward and backward whirl responses where it has been always assumed that the backward whirl zone should precede the forward whirl zone. Here, two configurations of cracked rotor-disk systems are considered to study the effect of the angular acceleration and the unbalance force vector orientation with respect to the crack opening direction on the whirl response at the backward whirl zone of rotational speeds. The obtained numerical simulation results are verified through a robust experimental testing for system startup operations. The backward whirl zone is found here to appear immediately after the passage through the critical forward whirl rotational speed. The onset of the backward whirl is also found to be associated with a sharp drop in vibration whirl amplitudes. This backward whirl zone is found to be significantly affected by the unbalance force angle vector orientation and the shaft angular acceleration. More importantly, this zone of backward whirl orbits is not found to be preceding the critical forward whirl zone for the considered cracked shaft-disk configurations.
Capturing BW Zone in an Intact Rotor System
Authors: Alhammadi Fatima K. , AL-Shudeifat Mohammad A. , Shiryayev Oleg
Published: January 2019

Aircraft engines, aerospace rotating equipment, gas turbines, compressors, and rotors in several industrial and aerospace applications approach their nominal operational speeds after the passage through at least one of their critical rotational speeds. During the passage through the critical speeds, elevation in vibration amplitudes is usually observed due to the effect of residual unbalance in these real-life applications rotors. In all of the reported literature, the theoretical and numerical simulation results and the related Campbell diagrams suggest that the backward whirl (BW) zone should precede the passage through the critical forward whirl (FW) speed/speeds of such systems. Here, the existence of zones of rotational speeds at which BW orbits are expected to appear will be investigated immediately before and after the passage through the critical FW speed. Accordingly, startup operations of two different configurations of crack-free rotor-disk systems are considered in this numerical and experimental study. It is found out that there exist zone/zones of the shaft rotational speeds at which BW orbits are experimentally captured where these zones are localized immediately after the passage through the critical FW rotational speed during the startup operations. These BW zones are strongly affected by the acceleration of the shaft during the transient startup operations. These findings suggests that the BW should not necessarily precede the critical FW speed as suggested by the related Campbell diagrams.
An Experimental Study on the Convective Heat Transfer Behaviour of Diamond Nanofluids in Electronic Cooling Applications
Authors: Mashali Farzin , Languri Ethan M. , Davidson Jim , Kerns David , Alkhaldi Fahad
Published: January 2019

This study presents the convective heat transfer coefficient of 0.05 wt.% diamond nanofluids containing functionalized nanodiamond dispersed in a base fluid deionized (DI) water flowing in a conduction cold plate under turbulent flow conditions, experimentally. The conduction cold plate was heated via six cartridge heaters with a constant heat transfer rate. The primary experimental study has been implemented to investigate the thermal conductivity of diamond nanofluids which showed a higher effective thermal conductivity than that of the base fluid. In addition, nanofluid was flowed in a closed system with heating at the heat exchanger and cooling via a cooling tank to keep the inlet temperature constant to explore the convection heat transfer properties of diamond nanofluids. Results indicate that the convective heat transfer coefficient and Nusselt number of diamond nanofluid are higher than that of the DI water in a same flow rate, and these properties increased with increase in Reynolds number.
Mixed One-/Two-Dimensional Models With Node Dependent Kinematic Capabilities for the Analysis of Metallic and Composite Structures
Authors: Zappino Enrico , Carrera Erasmo
Published: January 2019

The present paper presents an innovative approach to connect one-/two-dimensional models using a unified formulation with node-dependent kinematic capabilities. These models can use a different kinematics approximation at each node of the element. Carrera Unified Formulation has been used to derive the governing equations in a compact and general form. The possibility to connect one- and two-dimensional elements, and eventually to refine the kinematic model locally, has lead to a general reduction of the computational costs guaranteeing the same numerical accuracy.
Mechanical Engineering Student Developed Lego Engineering Design Learning Activity for 6th Grade Science Students
Authors: Lai Heather L. , Bryant Laura
Published: January 2019

A linkage synthesis and analysis project from a 3rd year mechanical engineering Kinematics of Machines course at SUNY New Paltz was used by the ASME student section to develop a Lego based middle school activity to teach engineering design as a part of the new 6th grade New York State Science Learning Standards. This activity was brought to a local middle school, where mechanical engineering students from the ASME student section led the learning activity in four 6th grade science classes. The activity involved the building and testing of a mechanized soccer goalie, which included several design parameters selected by the 6th grade students based on the results of experimental measurements, using an engineering decision making process. The development and refinement of this activity is presented along with guidance for its implementation elsewhere.
Ground Level Integrated Diverse Energy Storage (GLIDES) Cost Analysis
Authors: Kassaee Saiid , Odukomaiya Adewale , Abu-Heiba Ahmad , Liu Xiaobing , Mench Matthew M. , O’Connor Patrick , M. Momen Ayyoub
Published: January 2019

With the increasing penetration of renewable energy, the need for advanced flexible/scalable energy storage technologies with high round-trip efficiency (RTE) and high energy density has become critical. In this paper, a techno-economic model of a novel energy storage technology developed by the Oak Ridge National Laboratory (ORNL) is presented and used to estimate the technology’s capital cost. Ground-Level Integrated Diverse Energy Storage (GLIDES) is an energy storage technology with high efficiency which can store energy via input of electricity and heat and supply dispatchable electricity. GLIDES stores energy by compressing and expanding a gas using a liquid piston. GLIDES performance has been extensively studied analytically and experimentally. This study aims to develop a comprehensive combined performance and cost modeling environment. With the desired system storage capacity kilowattage, storage time (hours), and an initial RTE guess as inputs, the model optimizes the selection of system components to minimize the capital cost. The techno-economic model described in this paper can provide preliminary cost estimates and corresponding performance for various system sizes and storage times.
Orthogonal Machining of Copper Alloy With a Hardness Gradient
Authors: Payton Lewis N.
Published: January 2019

An experimental and analytical investigation of the effects of hardness upon the classical orthogonal machining geometries was conducted using copper alloy with 12 levels of hardness as measured on the Brinell hardness scale. A real time data collection method permitted the collection of a large body of data for analysis. 720 experimental runs were analyzed. The experimental results were compared to thirteen geometrical models that have been formulated including Merchant’s and Piispanen’s independently derived orthogonal machining equations of the 1940’s. One model [1] was verified by the results of the experiment in copper when a regression study of the data was conducted. Their application of the minimum energy principle in deriving an expression for the shear front angle ψ, the onset of shear plane angle ϕ, and the tool face rake angle α, provided an accurate shear strain model that is well supported by the physical evidence. The resulting relationship: ψ=45°-φ+α2 is predictive. It correlates directly and strongly with the measured material hardness.
Hot Surface Ignition Properties of Jet-A/Canola Methyl Ester Blends in a Constant Volume Chamber
Authors: Duong Bach , Parthasarathy Ramkumar N. , Gollahalli Subramanya R.
Published: January 2019

In recent years, biofuels have emerged as an attractive alternative to traditional petroleum fuels due to their renewable and almost carbon-neutral nature. While the fundamental ignition properties of petroleum fuels are well understood, knowledge of ignition properties of biofuels and their blends with petroleum fuels is limited. Studies of the fundamental ignition properties of biofuels are important for the safety of storage and transportation of these fuels. The objective of this study was to compare the relative hot surface ignition properties of biofuel blends at different equivalence ratios in a constant-volume chamber. Properties that were measured in this study are: ignition energy, time interval for ignition, ignition surface temperature, and flame front velocities. The fuels studied were blends of Jet A (petroleum fuel) and canola methyl ester, CME (biofuel) over an equivalence ratio range of 0.75–2.0. A commercially available silicon carbide dryer ignitor was used as the ignition source and was located in the center of the combustion chamber. A high-speed camera recorded the propagation of the flame following ignition, allowing for the calculation of the flame front velocity. K-type thermocouples measured the temperature of the mixture at selected points inside the combustion chamber. It was found that the ignition temperature of the air-fuel mixture was nearly constant for all fuels at about 630°C (903 K). The ignition energy reached a minimum value around an equivalence ratio of 1.1–1.3 for all the blends.
Investigating the Progression of Alzheimer’s Disease Using Digital Volume Correlation Algorithm and Strain As a Metric
Authors: McCarty Annastacia K. , Bentil Sarah A.
Published: January 2019

In the United States, Alzheimer’s disease (AD) affects one in ten people ages 65 and older. In most patients, the first indication of AD is the inability to remember new information, and symptoms grow to include behavior changes and increasing confusion and suspicions surrounding loved ones and daily events. As the disease progresses, the cortex and hippocampus regions of the brain decrease in size, allowing the fluid-filled ventricles within the brain to increase. New and innovative therapies to delay the onset of the disease and progression of the symptoms are being discovered. For example, the antibody solanezumab is undergoing clinical trials to determine its ability to reduce the levels of beta-amyloid in the brain, a known risk factor of AD. Consequently, the ability to identify patients who could benefit from the therapies will be invaluable. The purpose of this study is to determine if the digital volume correlation (DVC) algorithm can detect and track the onset and progression of AD using magnetic resonance imaging (MRI) scans of the head. DVC measures the deformation and strain of the volumetric MRI dataset by tracking the changes in its grey value pattern. A collection of MRI datasets of a patient’s head, which include scans from a baseline visit and visits at 6 months, 12 months, and every 12 months thereafter, is used in our analysis. A strain is applied to each set of MRI scans prior to implementation of the digital volume correlation algorithm. The DVC algorithm is then applied to the dataset and the resulting error between the expected and calculated strain is computed. A decrease in the contrast of the MRI dataset will correlate to additional error by the algorithm. As a result, an increase in the calculated strain error is anticipated to correlate with an increase in the ventricles in the brain, or progression of the disease, over the time period of interest.
Estimation of Hip and Ankle Visco-Elastic Parameters During Quiet Standing
Authors: Cerda-Lugo Angel , Gonzalez Alejandro , Cardenas Antonio , Piovesan Davide
Published: January 2019

Balance control naturally deteriorates with age, so it comes as no surprise that nearly 30% of the elderly population in the United States report stability problems that lead to difficulty performing daily activities or even falling. Postural stability is an integral task to daily living which is reliant upon the control of the ankle and hip. To this end, the estimation of ankle and hip parameters in quiet standing can be a useful tool when analyzing compensatory actions aimed at maintaining postural stability.

Using an analytical approach, this work builds upon the results obtained by the authors and expands it to a two degrees of freedom system where the first two modes of vibration of a standing human are considered. The physiological parameters a second-order Kelvin-Voigt model were estimated for the actuation of the ankle and hip. Estimates were obtained during quiet standing when healthy volunteers were subjected to a step-like perturbation.

This paper presents the analysis of a second-order nonlinear system of differential equations representing the control of lumped muscle-tendon units at the ankle and hip. This paper utilizes motion capture measurements to obtain the estimates of the control parameters of the system. The dynamic measurements are utilized to construct a simple time-dependent regression that allows calculating the time-varying estimates of the control and body segment parameters with a single perturbation.

This work represents a step forward in estimating the control parameters of human quiet standing where, usually, the analysis is either restricted to the first vibrational mode of an inverted pendulum model or the control parameters are assumed to be time-invariant. The proposed method allows for the analysis of hip related movement in the control of stability and highlights the importance of core muscle training.
Thermal Transport in Defective Actinide Oxides
Authors: Resnick Alex , Mitchell Katherine , Park Jungkyu , Maier Hannah , Farfán Eduardo B. , Yee Tien , Velasquez Christian
Published: January 2019

The present study employs a molecular dynamics simulation to explore thermal transport in various oxide nuclear fuels with defects such as uranium oxide and plutonium oxide. In particular, the effect of vacancy and substitutional defects on the thermal transport in actinide oxides are investigated. It is found that the thermal conductivities of these oxide nuclear fuels are significantly reduced by the presence of vacancy defects. In spite of their small size, oxygen vacancy is shown to alter the thermal conductivity of oxide fuels greatly; 0.1% oxygen vacancy reduces the thermal conductivity of plutonium dioxide by more than 10% when the number of unit cell in length is 100. It was shown that the missing of larger atoms alters the thermal conductivity of actinide oxides more significantly. For the case of uranium dioxide, 0.1% uranium vacancies decrease the thermal conductivity by 24.6% while the same concentration of oxygen vacancies decreases the thermal conductivity of uranium dioxide by 19.4%. However, the uranium substitutional defects are shown to have a minimal effect on the thermal conductivity of plutonium dioxide because of the small change in the atomic mass.
Numerical Examination of Jets Induced by Multi-Bubble Interactions
Authors: Mondal Joydip , Mishra Arpit , Lakkaraju Rajaram , Ghosh Parthasarathi
Published: January 2019

Jets produced by the interaction of collapsing cavitating bubbles containing high-pressure gases can be utilized for wide variety of applications e.g. particle erosion, medical purposes (lithotripsy, sonoporation), tannery effluent treatment, etc. Among the many parameters, this jetting is largely influenced by spatial orientation of bubbles, their times of inception, relative bubble size ratio. In this context, multiple cavitating bubbles are able to generate numerous simultaneous jets, under suitable conditions, hence operating over a wider coverage area. Such multi-bubble arrangements can go a long way in enhancing the erosive impact on a target location even at cryogenic temperature (< 123 K) and hence necessitate investigation.

In this paper, different configurations of multiple-bubble interactions are numerically simulated to examine jets directed towards a target location (fictitious particle, cell etc.) using computational fluid dynamics. No phase change is considered and the effect of gravity is neglected. The transient behaviour of the interface between the two interacting fluids (bubble and ambient liquid) is modelled using VOF (volume of fluid) method.

In this paper, results obtained for different bubble configurations through numerical simulation are validated against suitable literature and further explored to assess the resulting jet effects. The time histories of interacting bubbles are presented and the consequent flow-fields are evaluated by the pressure and velocity distributions obtained. The same calculation is repeated in cryogenic environment and the results are compared. An attempt is made to approach towards an optimum arrangement and conditions for particle erosion.