bluuebunny/crossref_metadata_2025 huggingface dataset:
El Espacio en la instalación sonora
Authors: Cerón Carolina Ortiz
Published: January 2019

La intención de este artículo es exponer el espacio como una de las principales preocupaciones artísticas en la instalación sonora desde distintos puntos de vista (artístico, estético y filosófico). Se toma como base de reflexión el pensamiento espacial de la obra filosófica Esferas, de Peter Sloterdijk, cuyo planteamiento fundamental radica en que la vida es una cuestión de forma, que cualquier espacio imaginado y creado por la humanidad manifiesta una manera de hacer y de ser, y que es en ese lugar donde se puede comprender la esencia del hombre. Se analizan entonces obras de diversos artistas cuyo trabajo se ha desarrollado en gran medida bajo la forma de esta práctica, con el fin de tratar la experiencia del espacio desde la creación sonora. Entre ellos están Max Neuhaus, Robin Minard y Céleste Boursier-Mougenot. Finalmente, se entreteje una conexión entre las obras analizadas y varias cualidades del pensamiento espacial de Sloterdijk para exponerlas en tanto espacios de creación que dejan entrever una manera de relacionarse con el entorno por medio de lo que se escucha. Qué se oye y cómo se lo comparte son preguntas innatas a la experimentación de esta forma artística, de ahí la importancia de la inmersión, la escucha, el recorrido. Bajo esta perspectiva, las obras analizadas son comprendidas como territorios que interrogan artística y estéticamente la escucha, actividad cuyo dinamismo transforma, interroga, redime los espacios de vida.
The Paradox of Music Transgressions: Noise as a Libidinal Energy
Authors: Campesato Lilian
Published: January 2019

Este artículo hace parte de un proyecto de investigación más amplio que considera el ruido como un agente de transformación musical. Desde esta perspectiva, hago una reflexión sobre los conceptos psicoanalíticos de represión y pulsión de muerte. En este contexto, estos conceptos están vinculados al proceso de rechazo, aceptación y transgresión de algunos elementos que constituyen la base de la creación artística. La relación entre la transgresión y la aceptación del ruido puede entenderse como un proceso dialéctico y dinámico. Por un lado, el ruido puede entenderse como un evento perturbador, indeseable, suprimido y reprimido; por otro lado, puede convertirse en algo aceptable y deseable cuando se incorpora como un elemento estético. Este proceso oscilatorio de aceptación y rechazo puede estar relacionado con dos conceptos de la teoría psicoanalítica freudiana: la represión y la pulsión de muerte. Estos conceptos pueden ayudar a comprender el regreso de lo que se reprimió, lo que se debe evitar y lo que se percibe como ruido, conectando este “regreso” a la idea de recordar algo que ha sido reprimido. Al hacer este paralelo entre ruido y psicoanálisis, busco comprender el mecanismo por el cual un elemento incómodo, ruidoso y a veces destructivo se vuelve crucial para superar una inercia conservadora y así activar un resorte que impulsa la dinámica cultural. Aunque denota una paradoja, esta dinámica permite la incorporación de lo que se considera indeseable y es una operación esencial en los procesos de transformación de la música.
The Effect of Local Force Control on Punch Forces During Panel Forming
Authors: Emblom William J.
Published: January 2019

Methods for improving the robustness of panel forming including the introduction of process sensing and feedback and control has resulted in significant gains in the quality of parts and reduced failures. Initial efforts in implementing closed-loop control during panel forming used active tool elements to ensure that the total punch force followed prescribed trajectories. However, more recently local forces within the tooling have been demonstrated to not only follow desired force trajectories but have been shown to increase the operational envelope of the tooling compared to open-loop tests and even closed-loop test where the total punch force had been controlled. However, what has not been examined is the effect of local force, especially during closed-loop control panel forming operations on the total punch force measured during forming. This paper addresses this by comparing the results of both open-loop tests and closed-loop tests and examining the effects on both local and total punch forces. It was found that while open-loop forming with various constant draw bead depths resulted in varying total punch forces, once closed-loop control was implemented the total punch forces followed virtually identical trajectories.

The tooling for this project included local force transducers and a total punch force transducer. In addition, active draw beads could be controlled during forming and a flexible blank holder with variable blank holder forces were part of the setup.
Experimental and Theoretical Investigations on Tool Wear and Surface Quality in Micro Milling of SiCp/Al Composites Under Dry and MQL Conditions
Authors: Deng Ben , Wang Haowei , Peng Fangyu , Yan Rong , Zhou Lin
Published: January 2019

During the machining processes of ceramic particle reinforced metal matrix composites, the severe tool wear constrains the quality and cost of the parts. This paper presents the experimental and theoretical investigations of the tool wear behavior and surface quality when micro milling the 45vol% SiCp/Al composites under dry and minimum quantity lubrication (MQL) conditions. The results of scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) show that the wear mechanism of diamond coated micro mills are adhesive, abrasion, oxidization, chipping and tipping, even though it has been reported that abrasion is the most important tool wear mechanism when machining particle reinforced metal matrix composites. Compared with dry lubrication condition, the environmentally friendly MQL technique can enhance the tool life and surface roughness, and reduce the cutting force significantly under given cutting parameters. Then, finite element (FE) simulations are employed to investigate chip formation process in micro orthogonal cutting to reveal the effects of reinforced particle on tool wear and surface quality. The FE simulations shows the local high stress, hard reinforced particles in metal matrix, debonded and cracked particles are the key factors leading to the severe tool wear and the unsmoothed surface morphology.
Compliant Translational Double Exact Dwell Mechanism
Authors: Tekes Ayse , Lin Hongkuan
Published: January 2019

Linkage or cam follower types of mechanisms are designed to create dwell motion when the interest of point on the mechanism is expected to stay at rest while the input is constantly supplied to the driven link. Generally, six bar linkages consisting of a four bar crank rocker mechanism actuating a slider crank are considered for linkage type mechanisms. A novel compliant translational double exact dwell mechanism incorporating the buckling motion of an initially straight flexible member as its members is introduced in this paper. Buckling members are designed to create dwell motion as a compliant mechanism that is easy to manufacture and require minimum number of components and assembly.

This partially compliant five bar mechanism consists of two rigid links as the crank and the slider, and two flexible links as the coupler and the last link. Kinematic analysis of the mechanism is broken into two parts. The first one is a flexible pinned-pinned beam attached to a slider and the second one is the pinned-pinned flexible beam which is attached to a rotating crank. Large deflection analysis of pinned-pinned buckling beam is obtained by solving first and second kind of elliptic integrals in Matlab. Load required to displace the slider and the maximum bending moment restored on the pinned-pinned beam are analyzed by changing the normalized offset from 0 to 1.

A mechanism is said to be linear if the slope of the load-deflection curve remains positive during deformation. Slope of the normalized load deflection curves at various offsets are explored and design limitations providing a stable buckling behavior is discussed. Pinned-pinned buckling beams are represented by springs possessing the same load-deflection characteristics as the compliant beams where the nonlinear spring function is described by a 4th order polynomials fitted to the load-deflection curves both for the beam attached to the slider and the beam attached to the driven crank. The emphasis is placed on the dynamic response of the double exact dwell motion profile. Simulation results are studied using Solidworks model, and Matlab. Slider stays at rest until the maximum bending moment of the coupler flexible link is achieved creating the dwell, snaps to its maximum position and on the return creates a momentary dwell since the flexible follower behaves like a rigid link. Desired dwell motion can be accomplished by changing the flexible beam parameters such as its length, thickness and offset ratio.
Modelling on Predicting Pressure Distribution and Capacity of Foil Thrust Bearing
Authors: Xu Zheng , Ji Fenzhu , Zhou Yu , Wu Fanyong , Ding Shuiting
Published: January 2019

Air bearing is future main supporting way of high-speed machinery such as turbocharger, micro gas-turbine engine. Foil bearing is a new type of air bearing which is lubricated by the thin-film air with its self-adapting elastic foil structure. It has many significant advantages such as non-pollution, longer working life, higher reliability, and lower friction loss. Different from foil journal bearing, in present the study of foil thrust bearing is extremely insufficient, especially about how to accurately predict the pressure distribution and efficiently improve the bearing capacity. The pressure distribution prediction of foil thrust bearing air film directly impacts the bearing stiffness and damping design, and then influences bearing capacity. The Reynolds equation commonly used to do such estimation is not accurate enough since the influence of temperature on air property parameters is ignored. The inaccurate prediction leads a catastrophic reduction to the bearing performance. In order to solve this problem, we propose a model to accurately predict the pressure distribution and capacity of foil thrust bearing using CFD method, as well estimating the relationship between air film clearance thickness, rotation speed, environment temperature and the capacity. Firstly, we simulate the pressure distribution of air film and then evaluate the simulation result by constrained experiments. We also correct the simulation by using modified air parameters obtained from experiment. The experimental results indicate our corrected simulation model is accurate with error less than 4%. Secondly, we compare simulation and experiment pressure results under different conditions. The model accuracy sensitivity varies within 10% under different rotation speed, air film clearance thickness and environment temperature. Finally, we use corrected model to analyze capacity impact parameters. We find the capacity of bearing increases with the decreasing of average air film clearance thickness under fixed speed of the thrust disc. The smaller clearance thickness is, the more influence its variation has on the bearing capacity. Meanwhile, the capacity of the bearing decreases with the reducing thrust disc speed under constant clearance thickness, and it decreases more obviously in the lower speed. The capacity reaches its largest under 200 °C and it falls with the increases or decreases of environment temperature. The model in this paper provides important theoretical foundation when designing the stiffness, damping and temperature control of each bearing area.
Biomedical Devices Using Shape Memory Polymer Foams for Treatment of Intracranial Aneurysms
Authors: Wang Jingyu , Luo Jishan , Kunkel Robert , Liu Yingtao , Bohnstedt Bradley , Lee Chung-Hao
Published: January 2019

This paper presents a novel medical device developed using shape memory polymer (SMP) foams for the endovascular treatment of intracranial aneurysms (ICAs). The SMP foam is fabricated, characterized, and experimentally investigated to better understand their potential for endovascular embolization of ICAs. Polyurethane-based SMP is successfully synthesized and characterized. The SMP foam is manufactured using cast molding, and characterized using an electro-thermal triggering mechanism to fully understand their shape recovery capability. The successful completion of this work will serve as a solid foundation for the development of new biomedical devices to treat intracranial aneurysms and develop an optimal releasing procedure for future animal study.
Modelling Produced Water Re-Injection Scaling Compability Performance in Matured Hydrocarbon Aquifer, Nigeria
Authors: Fashanu Theophilus A. , Idialu Peter O. , Abhulimen Kingsley E.
Published: January 2019

Computational models are developed to predict scale formations, compatibility and injection performance of produced water re-injection in mature hydrocarbon aquifer fields. The models are based on a robust numerical strategy that considered representative K-factors to predict correction for injectivity decline profiles. Simulations in COMSOL Multi-physics environment evaluate scaling effect to determine multi-reservoir commingling phenomenon in matured fields. Results demonstrated that geochemical scaling limit feasible and sustainable water injection performance that could impact petroleum recovery. Fracturing out of water zone was also significant near top and bottom interval cross flow of injection well requiring additional pressure of 100 to 200 psi to initiate fracturing. This requirement excluded fracturing in produce water most re-injection fields with attendant scaling effect.
Experimental Investigation on Heat Transfer Characteristics of Smooth Water Wall Tube of an Ultra-Supercritical CFB Boiler
Authors: Wang Wenyu , Liang Ziyu , Wan Li , Liu Dan , Yang Dong
Published: January 2019

In this study, an experimental investigation was carried out to explore the heat transfer characteristics of the smooth water wall tube of an ultra-supercritical circulating fluidized bed (CFB) boiler. The ranges of the test pressure, mass flux, and heat flux were 23–32 MPa, 550–1200 kg·m−2·s−1, and 200–560 kW·m−2, respectively. The material of the tube used in the test was 12 Gr1MoVg. The diameter and wall thickness were 30 and 5.5 mm, respectively. The length of the test section was 2 m. The effects of the pressure, mass flux, heat flux, buoyancy, and flow acceleration on the heat transfer characteristics were analyzed. The formulas of the heat transfer coefficient were fitted, and the existing classical formula was used to evaluate the experimental data. The mechanism of heat transfer enhancement and deterioration of the tube were also investigated. Results showed that at the area of supercritical pressure, the wall temperature gradually increased with the increase of enthalpy in the pseudo-enthalpy region and sharply increased with the increase of enthalpy in the low-enthalpy region (enthalpy < 1200 kJ kg−1) and high-enthalpy region (enthalpy > 2400 kJ kg−1). This phenomenon indicated that heat transfer enhancement occurs near a pseudo-critical point. The increase of heat flux resulted in rapid heat transfer deterioration. Thereafter, the wall temperature rose immediately. The deterioration was delayed with the increase of mass flux and pressure. The effect of buoyancy and flow acceleration on the heat transfer concentrated on the pseudo-critical temperature of the fluid. Among the five selected heat transfer correlations, the Jackson and Bishop correlations agreed well with the experimental data.
Modeling and Performance Analysis of a Dual-Shaft Counter-Rotating Gas Turbine
Authors: Zhou Qiao , Yin Zhao , Tan Chun-qing , Gao Qing , Tian Yong-sheng
Published: January 2019

This paper proposes a modeling method for the 1+1/2 vaneless counter rotating turbine (VCRT) and carries out performance analysis of a micro gas turbine (MGT) with VCRT at off design conditions.

The first task of this paper is to obtain performance characteristics maps and develop a characteristics modeling method of VCRT. The VCRT characteristics maps are obtained through 3-D CFD calculation. High pressure turbine (HPT) corrected rotational speed, shaft rotating speed ratio defined as the high pressure (HP) shaft rotational speed divided by low pressure (LP) shaft rotational speed, and the VCRT total expansion pressure ratio are selected to model a 3-D low pressure turbine (LPT) characteristics maps. However, the HPT characteristics map modeling method remains the same as the conventional one.

An overall performance simulation model is established in Matlab/Simulink and validated by software GasTurb. The VCRT engine consumes fuel at a higher rate when delivering same power compared with the conventional gas turbine due to LPT performance degradation. When the relative LP shaft speed ranges from 100% to 96%, the performance of the VCRT engine and conventional engine is almost equivalent. As the LP shaft speed continues to drop off, however, the VCRT engine performance degrades considerably.

The results indicate that it is crucial to design VCRT with a wide range of efficiency, especially the LPT. The VCRT engine control law also must be effectively optimized to ensure the engine performs well at part load working conditions.
Triaxial Gas Turbine Performance Analysis for Variable Power Turbine Inlet Guide Vane Control Law Optimization
Authors: Wang Tao , Tian Yong-sheng , Yin Zhao , Gao Qing , Tan Chun-qing
Published: January 2019

This paper proposes an inlet guide vane control law optimization technique for improving the off-design working condition thermal efficiency of triaxial gas turbine. Gas turbine dynamic and steady component-level simulation models are established in MATLAB/SIMULINK via Newton-Raphson algorithm based on component characteristic maps. After validating the models against experimental data and Gasturb software, they are applied to determine the effects of guide vane angle on gas turbine performance parameters.

High Efficiency Mode (HEM) is utilized to adjust the power turbine inlet guide vanes to enhance the gas turbine efficiency and decrease the specific fuel consumption under off-design working conditions on account of the above gas turbine overall performance analysis results. The optimal angles of power turbine inlet guide vanes for various working conditions are acquired based on the steady gas turbine model as-established. HEM enhances the gas turbine’s thermal efficiency without exceeding its temperature or rotational speed constraints. The Radial Basis Function (RBF), a three-layer, feedforward neural network, is employed to fit the optimal guide vane angles and establish the corresponding relationship between the angles and various working conditions by system identification. The control strategy and gas turbine dynamic simulation model are tested in MATLAB/SIMULINK to verify their effects on gas turbine performance. The guide vane angle is found to significantly influence the gas turbine operating parameters, and HEM to effectively optimize gas turbine performance even within unpredictable atmospheric environment and working conditions.
Modeling Crane Induced Ship Motion Using the Moving Frame Method
Authors: Jardim Paulo Alexander Jacobsen , Rein Jan Tore , Haveland Øystein , Impelluso Thomas J.
Published: January 2019

A decline in oil-related revenues challenges Norway to focus on new types of offshore installations and their maintenance. Often, ship-mounted crane systems transfer cargo or crew onto marine structures such as floating windmills. This project analyzes the motion of a ship induced by an onboard crane in operation. It analyzes the motion of a crane mounted on a ship using The Moving Frame Method (MFM). The MFM draws upon Lie group theory and Cartan’s Moving Frames. This, together with a compact notation from geometrical physics, makes it possible to extract the equations of motion, expeditiously. This work extends a previous project that assumed many simplifications. It accounts for the masses and geometry of all components. This current approach also accounts interactive motor couples and prepares for buoyancy forces and added mass. The previous work used a symbolic manipulator, resulting in unwieldy equations. In this current phase, this research solves the equations numerically using a relatively simple numerical integration scheme. Then, the Cayley-Hamilton theorem and Rodriguez’s formula reconstructs the rotation matrix for the ship. Furthermore, this work displays the rotating ship in 3D, viewable on mobile devices. WebGL is a JavaScript API for rendering interactive 3D and 2D graphics within any compatible web browser without the use of plug-ins. This paper presents the results qualitatively as a 3D simulation. This research proves that the MFM is suitable for the analysis of “smart ships,” as the next step in this work.
Modelling Subsea ROV Motion Using the Moving Frame Method
Authors: Austefjord Katrine Oen , Hestvik Martin Oddøy , Larsen Linn-Kristin Skeide , Impelluso Thomas J.
Published: January 2019

Norway conducts operations on a variety of structures in the North Sea; e.g. oilrigs, monopole windmills, subsea trees. These structures often require subsea installation, observation, and maintenance. Research and technology that can improve the efficiency of these operations are of high interest to the nation. A remotely operated vehicle (ROV) can assist in these operations. However, the ROV pilot must observe and adjust the vehicle and its motion in accordance with its task, but modified due to impending forces. Automation of this motion is the desired goal. This paper researches the motion of an ROV induced by the motion of the robotic manipulators, motor torques, and fluid buoyancy. The research introduces a new method in engineering dynamics: the Moving Frame Method (MFM). Lie Group Theory and Cartan’s notion of moving frames are the foundation of the MFM. This research extends previous work in significant ways. This research accounts for the motor torques, fluid viscosity and the mass of the manipulator’s arms. Interactive visualization on hand-held devices is also an integral part of this research. The Web Graphics Library (WebGL) is a JavaScript API for rendering interactive 3D and 2D graphics within any compatible web browser without the use of plug-ins. This work visualizes the results, interactively, on 3D web pages, viewable on cell phones using WebGL. This work invites further research into improved numerical methods, solid/fluid interaction and the design of Autonomous Underwater Vehicles (AUV). AUVs beckon an era of Artificial Intelligence when machines think, communicate and learn. Rapidly deployable software implementations will be essential to this task. This paper demonstrates the MFM clears the path toward such technological innovations.
Effect of Eccentricity on the Nonlinear Dynamic Behavior of a Cam and Follower Mechanism With Clearance
Authors: Yousuf Louay S. , Marghitu Dan B.
Published: January 2019

This study evaluate the relationship between flat-faced follower’s offset and Lyapunov exponent. The nonlinear dynamic behavior has been investigated based Lyapunov exponent value. Two types of follower offset such as (e = 10, and 20 mm) has been examined from each side of the cam radial line. The simulation process has been done by using solidwork program. The power spectrum of Fast Fourier Transform and phase plane have been examined the follower non-periodicity during follower motion. The optimum follower offset that would minimize Lyapunov exponent is determined. The system with follower guide’s clearance C = 2 mm and e = 20 mm has larger Lyapunov exponent than the others at cam rotational speed N = 1200 rpm. The signal of follower motion is processed by using MATLAB program.
Efficient Uncertainty Quantification for Biotransport in Tumors With Uncertain Material Properties
Authors: Alexanderian Alen , Reese William , Smith Ralph C. , Yu Meilin
Published: January 2019

We consider modeling of single phase fluid flow in heterogeneous porous media governed by elliptic partial differential equations (PDEs) with random field coefficients. Our target application is biotransport in tumors with uncertain heterogeneous material properties. We numerically explore dimension reduction of the input parameter and model output. In the present work, the permeability field is modeled as a log-Gaussian random field, and its covariance function is specified. Uncertainties in permeability are then propagated into the pressure field through the elliptic PDE governing porous media flow. The covariance matrix of pressure is constructed via Monte Carlo sampling. The truncated Karhunen–Loève (KL) expansion technique is used to decompose the log-permeability field, as well as the random pressure field resulting from random permeability. We find that although very high-dimensional representation is needed to recover the permeability field when the correlation length is small, the pressure field is not sensitive to high-oder KL terms of input parameter, and itself can be modeled using a low-dimensional model. Thus a low-rank representation of the pressure field in a low-dimensional parameter space is constructed using the truncated KL expansion technique.
Relating Bone Intra-Cortical Elastic Stiffness to EDX Spectroscopy Mineralization Measurements
Authors: Hage Ilige S. , Hage Ré-Mi , Seif Charbel Y. , Hamade Ramsey F.
Published: January 2019

It is widely recognized that bone mineral content is a main contributor to cortical bone stiffness. Previous works by the authors revealed that stiffness of mid-diaphysis cortical bone increases with increasing radial position from interior to exterior regions. In this work, we correlate this radial cortical stiffness to the chemical composition of several bone rings cut from 2-year old bovine cow femur (collected fresh from butcher). This mineralization is quantified using energy-dispersive X-ray (EDX) spectroscopy. On each bone ring, five regions are assigned along a 4 mm radial line covering the entire cortical wall thickness. Locations along the radial distance are assigned to acquire the chemical analysis spectrum. Calcium (Ca) and Phosphorus (P) elements chemical elements are traced/detected. Measured mineralization results are expressed as per weight percent concentration (wt %). These elemental results for Calcium (Ca) and Phosphorus (P) are correlated to radial position and stiffness values using statistical analysis (SPSS®). Calcium (Ca) and Phosphorus (P) elements were positively correlated with stiffness values and radius whilst Ca/P ratio was almost constant with the radius. Findings suggest that with increasing radius, Ca (wt%) and P (wt %) showed a fairly increasing trend that correlates to increasing stiffness values proving that increased bone mineralization would contribute to cortical bone stiffness.
Ecological Optimization for an Endoreversible Chemical Pump With Three Mass Reservoirs
Authors: Chen Lingen , Xia Dan , Feng Huijun , Xia Shaojun
Published: January 2019

This paper firstly educes an energy-based ecological function (EF) which is a compromise between energy pumping rate (EPR) and dissipation of EPR for an endoreversible chemical pump (CP) cycle. By solving the equations of Euler Lagrange, the fundamental optimization relationships of the EF and coefficient of performance (COP) for the CP cycles with linear mass transfer (MT) law and diffusive MT law are derived. The numerical calculations to analyze the influences of the cycle parameters on the relationship between the EF and COP are provided, and the influence of two different MT laws on the EF and COP characteristic is discussed in detail. The maximum EF of the cycle with the linear MT law is bigger than that with the diffusive MT law. The results obtained in this paper can be applied to design a class of devices, such as photochemical, electrochemical and solid-state apparatus as well as mass exchangers, etc.
Influence of Surface Pretreatment on the Hydrophobic Silane Coating on AISI 304 Steel
Authors: Baruwa Akinsanya Damilare , Oladijo Oluseyi Philip , Maledi Nthabiseng , Akinlabi Esther Titilayo
Published: January 2019

The influence of surface pretreatment on the integrity of Tridecafloro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) coating on the substrate is presented. FOTS is a hydrophobic organic compound deposited on the SS 304 surface to enhance the corrosion protection of the metal. The surface was pretreated with silicon oxide, plasma oxide and both served as adhesions before the coating was deposited on the substrate by atomic layer deposition technique. The coatings were characterized by scanning electron microscope (morphology), atomic force microscope (surface roughness). The chemical composition and bonding structure were obtained by X-ray diffraction (XRD) and Attenuated-Fourier transform infrared (ATR-FTIR). The durability of the coating in corrosive media was investigated through electrochemical polarization and electrochemical impedance spectroscopy (EIS). The results obtained showed that silicon oxide pre-treated steel gave a better stability and improved properties to the coating than the plasma oxide pre-treated surface, and was distinctly discussed.
Design and Optimization of a Tidal Turbine and Farm
Authors: Mayeed Mohammed S.
Published: January 2019

Tidal ocean power is a dependable and dense form of renewable energy which is a relatively underdeveloped field. This study optimizes a tidal turbine with respect to performance and economics, and then optimizes a farm to be economically feasible.

It was determined that the southeastern portion of the Gulf Stream, Florida current, would be used for the tidal turbine system as it has some of the world’s fastest velocities and is relatively close to shore. The vertical axis designs were ruled out from extended research on turbine design for their lower efficiency in general. Only horizontal axis designs were tested in simulated environments. Using SolidWorks Flow Simulation and SolidWorks Simulation, turbine models were optimized and selected as having the potential for the greatest energy extraction. Static and fatigue analyses were conducted on the optimized models in order to prevent premature failure. Cost analysis was also performed on the turbine models and the model that had the lowest initial cost as well as the highest power generation was chosen for farm development. The optimized design produced reasonable amount of power considering varying velocities throughout the day having a diameter of about 30 m. Through fatigue analysis the optimized design also showed long enough lifetime so that a good return on investment can be acquired.

The single optimized turbine was then placed in a farm, and the farm’s shape and arrangement were tested and optimized so that the best arrangement and distances between units could be found. It was found that a farm 1.25 kilometers by 20 kilometers consisting of 800 turbines would be optimal. The farm would produce an average of 249.33 megawatts for a profit of $294.88 million dollars annually. The farm would pay for itself in 7.12 years and have an expected life span of 26.1 years which was obtained through fatigue analysis.
A Central Difference Finite Volume Lattice Boltzmann Method for Simulation of 2D Inviscid Compressible Flows on Triangular Meshes
Authors: Karbalaei Alireza , Hejranfar Kazem
Published: January 2019

In this work, a central difference finite volume lattice Boltzmann method (CDFV-LBM) is developed to compute 2D inviscid compressible flows on triangular meshes. The numerical solution procedure adopted here for solving the lattice Boltzmann equation is nearly the same as the procedure used by Jameson et al. for the solution of the Euler equations. The integral form of the lattice Boltzmann equation using the Gauss divergence theorem is applied on a triangular cell and the numerical fluxes on each edge of the cell are set to the average of their values at the two adjacent cells. Appropriate numerical dissipation terms are added to the discretized lattice Boltzmann equation to have a stable solution. The Boltzmann equation is discretized in time using the fourth-order Runge-Kutta scheme. The computations are performed for three problems, namely, the isentropic vortex and the supersonic flow around a NACA0012 airfoil and over a circular-arc bump. The effect of changing the grid resolution and the dissipation coefficients on the accuracy of the results is also studied. Results obtained by applying the CDFV-LBM are compared with the available numerical results which show good agreement.
Mechanical Properties of 3D Printed Metals
Authors: Allameh Seyed M. , Harbin Brianna , Leininger Bailey
Published: January 2019

With the advent of 3D printing technology growing fast, it is important to determine the properties of objects made by this new process. Since some sensitive products, used in life-sustaining applications, are currently made by 3D printing, the reliability and durability of such components must be closely examined. Mechanical properties of metals may vary with the direction of heat transfer during solidification. This study presents the results of tensile tests, conducted at microscale on samples extracted from 3D printed metals. The implications of the variation of strength with solidification direction on the reliability of such metallic objects are discussed.
Large Eddy Simulation of Ventilated Pump-Turbine for Wastewater Treatment
Authors: Daskiran Cosan , Attiya Bashar , Altimemy Muhannad , Liu I-Han , Oztekin Alparslan
Published: January 2019

Large eddy simulation (LES) is conducted to characterize oxygen dissolution in the draft tube of a pre-designed and optimized modular pump-turbine system. The air injection is applied over the peripheral surface on the draft tube. Mixture multiphase model is used to predict the spatial and temporal distribution of the air and the water. The simulation is conducted at the best efficiency point with a Reynolds number of 1.06 × 107 which is based on the rotation speed and the reference diameter of the runner. The vorticity is suppressed inside the draft tube, and the standard deviation of the power generation is decreased roughly 70% after aeration. The power generation is reduced by approximately 4–5% with peripheral aeration. Almost uniform dissolved oxygen concentration of 2–3 mg/l is observed in the radial direction near the outlet which is more than sufficient for wastewater treatment process.
Modified Laparoscopic Tool for Enhanced Haptic Feedback
Authors: Kumar Rajesh , Mukherjee Sudipto
Published: January 2019

Laparoscopic Devices are known to be used in Minimal Invasive Surgeries. However, the devices are unable to transmit the spectrum of feedback of the tissue to the hands of the surgeon, which makes the surgical procedure difficult. We have demonstrated a parameterization for the loss in feedback due to backlash and friction. Backlash is correlated to the joint clearances while friction correlates to joint clearance as well as the surface finish of mating pairs, though joint clearances don’t affect the friction coefficient largely. The laparoscope behavior has been dynamically modeled to understand and predict the behavior. Also, the cost to manufacture the graspers has been weighed against force bandwidth and reliability of improving the joint tolerances of the device so that it is able to transmit the desired force bandwidth. We conclude that to achieve kHz force bandwidth through purely mechanical means would entail prohibitively expensive manufacturing means and hence, we propose an alternate design. The alternate design makes the system deterministic without uncertainty in the position of the joint pins. The kinematically constrained joints in the new device completely transmit the input force spectrum at frequencies of multiple kHz. The non-sophisticated alteration in the original device doesn’t significantly alleviate the cost and eludes the loss of tactile sensation.
Numerical Analysis of Heat Transfer and Fluid Flow in Micro-Welding Using CFD
Authors: Shah Divyaj , Sewatkar C. M. , Godbole Ketaki
Published: January 2019

Laser welding is used to join metals of small thickness. The heat affected zone in this process is very small and the temperature gradients encountered are very large (of the order of 104K/mm). We have used numerical methods to analyze the effect of various parameters. For the present study, an in-house C code was developed to model the laser welding process. A Finite Volume based discretization was done and a Semi-Explicit method was used to solve the governing equations. Conduction mode heat transfer was considered by assuming no vaporization of the molten metal. The effect of various parameters like beam intensity and beam radius were studied on the weld dimensions. The beam intensity was varied from 5.2KW to 15KW while the beam radius was varied from 0.14mm to 0.35mm. The effect of welding angle was also studied on the weld dimensions. The welding angles used for the study were 0°, 26.5°, 45° and 56°. It was found that the weld width and depth increased with an increase in beam intensity and a decrease in beam radius, while the weld depth decreased with an increase in welding angle. The change in heat transfer and fluid flow was also studied by varying these parameters.
CAD-Based Tolerance Analysis in Preliminary Design Stages Enabling Early Tolerance Evaluation
Authors: Goetz Stefan , Schleich Benjamin , Wartzack Sandro
Published: January 2019

Associated with manufacturing and assembly processes, inevitable geometric deviations have a decisive influence on the function and quality of products. Therefore, their consideration and management are important tasks in product development. Moreover, to meet the demand for short development times, the front-loading of design processes is indispensable. This requires early tolerance analyses evaluating the effect of deviations in a design stage, where the product’s geometry has not yet been finally defined.

Since such an early tolerance consideration allows quick and economic design changes seeking for robust designs, it is advisable that the design engineer, who is entirely familiar with the design, should take this step. For this purpose, this paper presents an easy-to-use CAD-based tolerance analysis method for skeleton models. The relevant part deviations are represented by varying geometric dimensions with externally driven family tables. The approach comprises the strength of vector-based methods but does not require an expensive set-up of tolerance analysis models. Particularly, the novelty of this method lies in the CAD-internal sampling-based tolerance analysis of simple geometries without the use of expensive CAT software. This enables designers to evaluate the effect of tolerances already at the preliminary design stage. Using a case study, the presented approach is compared with the conventional vector-based tolerance analysis.
Preliminary Exploration of Cell-Based SAW Detection for Water Toxicity
Authors: Lee Kun-Lin , Li Fang , Nordin Anis Nurashikin , Voiculescu Ioana
Published: January 2019

Nowadays, many surface sensing mechanisms exist, not all of them can be applied in water-based environment. Most of surface sensing techniques were developed in air-based environment. In order to obtain a potential cell-based biosensor, the sensing method needs to be reliable and repeatable in liquid environment. Therefore, we adapt existing air-based surface acoustic sensor and promote the technology into water-based applications. The goal of this study is to apply surface acoustic waves (SAW) for water-based environment sensing. We will use shear horizontal wave (SH wave) as surface sensing mechanism. SH wave is a type of surface acoustic waves (SAW) which can be used for weight/mass sensing in the air environment. Interdigitated transducers (IDTs) induce the deformation of an ST-cut quartz crystal substrate in AC source and generate waves. With a thin layer of polymer like Parylene and polyimide, the SH wave will be confined between the interface of substrate and polymer layer without suffering the energy loss due to the liquid damping from above. The fundamental frequency of the SAW device is defined by the spacing between the electrodes of IDT. The frequency of interests for this research is below 100 MHz in water-based environment. Due to the stable frequency characteristics of ST-cut quartz in room temperature, this SAW device can be a good candidate for field applications. From an early IDTs design, investigation in material and IDTs configuration is necessary to improve signal quality in order to qualify for liquid phase cell-based bio-sensing applications. A simplified 3D unit cell FEM model is created to study the thickness effects of wave-guide and electrodes. Boundary conditions and assumptions are discussed in the modeling. The simulated eigenfrequency of SH mode is close to the theoretical fundamental frequency of the 64μm wavelength IDTs. The mass damping effects from gold electrodes is more significant than aluminum electrodes.
Study on Motor-Driven Gyroscopic Generator: Part 2 — Self-Acceleration by Power Feedback
Authors: Tajima Yuki , Hosaka Hiroshi , Oonishi Yoshinori
Published: January 2019

A motor-driven gyroscopic generator was developed that self-accelerates by power feedback. In a previous report, power generation of 1.8 W was confirmed, but an external power source was used to drive the spin motor. In this research, a method is presented to apply the power generated from the precession movement to the spin motor. It enables not only eliminating the power source but also accelerates the spin velocity. To achieve acceleration, however, the feedback circuit must boost the generated voltage since the counter voltage of the spin motor also increases with its velocity. Also, there is an optimum boosting rate that depends on the spin velocity. In this paper, first, a circuit equivalent to the gyro-generator system is presented and the coil resistance of the generator is shown to limit the highest boosting rate. Next, the rotor accelerating characteristics of four boosting circuits are compared. Electrical boosting is shown to have the same effect as mechanical impedance control. A numerical simulation is conducted and the power acceleration by boosting is also verified. Finally, a prototype generator is developed. The validity of theoretical results is verified and an output power of 0.1 W is obtained.
Influence of Ca-Ba and Sr Base Inoculants on Metallurgical and Mechanical Properties of Grey and Ductile Cast Irons
Authors: Patel Dhruv , Parmar Devendra , Jadeja Siddharthsinh
Published: January 2019

Microstructural adaptation of cast iron alloys by inoculation is a well-known practice to swell their mechanical properties. In foundries, several inoculants have been used to refine grain structure, and to obtain uniform distribution of graphite flakes. Inoculation is one of the most critical steps in cast iron production. The effectiveness of inoculants depends on melt temperature, method of addition, type of inoculants, and holding time. In this paper, the effect of Ca-based, Ba-based, Ca-Ba based and Sr-based inoculants on microstructure and tensile properties of grey cast iron IS-210 and spheroidal graphite iron IS-1862 is reported. Results showed both Ca and Ba based inoculants were effective in obtaining uniform distribution of flaky and nodular graphite in IS-210, and IS-1862 cast irons, respectively. But in a case of Sr-based inoculant were highly effective for increase the nodularity of SG cast iron as well as succeed supreme yield strength for both grey and ductile cast iron. The amounts of ferrite in the as-cast matrix are excess with controlled granulometry for elimination of primary carbide in Sr-based inoculant.
On Numerical Investigation of Water Injection to Screw Compressors
Authors: Rane Sham , Kovačević Ahmed , Stošić Nikola , Stupple Graham
Published: January 2019

Oil injection is widely used in screw compressors for lubrication, sealing and cooling purposes. More recently other, mainly lower viscosity fluids are used for the purpose, for example water. Water introduces new phenomena into the screw compressor process, one among them is evaporation. 3D numerical modelling is employed and presented in this paper for the detailed analysis of flow and thermodynamics process during injection of water in screw compressors. The advantage of such simulations is that realistic geometry of the rotors and the ports can be captured. In addition, the physical effects of fluid thermal interactions and leakage are directly taken into account by these models. Recent studies have shown that for oil free and oil injected air compressors a good agreement is achieved with measurements, in prediction of performance parameters. In these simulations the Eulerian-Eulerian multiphase modelling has been applied. To implement the same model for water injected compressors presents an additional challenge as the liquid water injected into the compression chamber changes phase and evaporates depending on the local saturation and thermodynamic conditions. Water also forms liquid film on the rotors and housing and thereby influences thermal changes.

In this paper a numerical model for water injected screw compressor that accounts for evaporation effects has been presented. Empirical form of the Lee (9) evaporation-condensation model for phase change has been applied in the compression chamber using the phase specific mass and energy sources. Calculation of the amount of water required to just saturate the compressed air at delivery pressure is used to set the mass flow rate of water at two operating speeds. The effect of the suction air temperature and relative humidity is studied. Evaporation inside compression chamber has two important physical effects, one is that the latent heat of evaporating water lowers the gas temperature and the other is the change of state from water to vapour. Including vapour as a third phase adds complexity to already challenging deforming grids required for screw domains. Hence a mass and energy source formulation is proposed in the presented study to account for the vapour phase change and evaporation effects, thus limiting the number of phases to be modelled. Local drop in gas temperature, distribution of water and regions of evaporation were identified by the simulations. Thermal hot spots on the rotor were located. Reduction in the leakage of gas and its exit temperature was well predicted by the model. Such simplified evaporation model can be further used in the design of water injected screw compressors and extended to predict thermal deformation of the rotors and the housing.
Development of Lower Body for Vehicle Driving Robot, HART
Authors: Sohn Kiwon , Markiewicz Mark , Keilich Stefan
Published: January 2019

This paper presents the development of a lower body for a full-size humanoid platform, HART (Human Assistive RoboT). The design objective of HART is to enable the robot to drive off-the-shelf vehicles in human-centered environments. To accomplish the goal, two technical design requirements which include kinematic adaptation and low-cost manufacturing are addressed and explored in this study. First, the overall hardware configuration and software control architecture of HART are presented. Then, the kinematic and dynamic specification of each joint and its design process are described. The kinematic analysis and motion planning of HART are also provided for the vehicle handling task such as control input manipulation. Last, the built platform is tested and evaluated through experimentations using two different types of ground vehicles.