bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steering Options for Maneuvering a Particle on a Surface
Authors: Hennessey Michael P. , Olson Derek A. , Shakiban Cheri 
Published: January 2020

Abstract
We consider the general problem of steering an infinitesimal propelled and steerable particle with no rotational inertia traversing on a mathematically smooth (vs. frictionless) surface, where both the speed and body yaw rate serve as inputs to the system and lateral motion is not allowed, i.e. through a no sideslip condition. More specifically, focus is on derivation of relevant state equations in control input form, numerical and visual confirmation of state equation accuracy through specific simulations, and exploring interesting approaches to nonholonomic path planning with associated numerical simulation and visualization. Given the state equations (3rd order), in the interests of practical validation, they were exercised by considering motion on a number of smooth surfaces. The surfaces were selected for a variety of reasons, such as: the resulting qualitative trajectory is known a priori, there exists an opportunity to check numerical results with respect to previous results, or the surfaces are iconic and/or are geometrically rich.
Nonholonomic steering on the surface is a very interesting and challenging problem and several approaches are investigated: (1) steering using sinusoids (detailed), (2) steering on a trajectory, and (3) “drive-and-turn” (valid in this case). Prior to implementing the steering using sinusoids algorithm, it was necessary to transform the system into “one-chained” form. The first step entailed conversion to an approximate one-chained form model that possesses a certain structure, from which the process established by Murray and Sastry can be successfully launched, where two special smooth scalar functions of the states are sought that possess special relationships to Lie-related distribution spaces associated with the control input vectors. Inputs are then transformed as well via specialized Lie derivatives. It was demonstrated through simulation that steering to an arbitrary system state on a faceted surface can be accomplished with sinusoidal inputs in only one maneuver set (i.e. maneuver A & B). Using this fact, the work presented culminates with steering to an arbitrary system state on a smooth surface that can be accomplished by essentially iterating on a steering algorithm that assumes the particle is on a plane tangent to the smooth surface at the desired destination. In this regard, it is shown that a sequence of maneuver sets converges rather quickly in the example demonstrated. Applications of this work pertain to the fairly general situation of steering a vehicle on a smooth surface, a practical vehicle navigation and control problem.
Computational Fluid Dynamics Modeling of a Heat Pipe Evacuated Tube Solar Collector Integrated With Phase Change Material
Authors: Pawar Vivek R. , Sobhansarbandi Sarvenaz 
Published: January 2020

Abstract
The increase in greenhouse gas and other global warming emissions makes it necessary to utilize renewable energy sources such as solar energy with high potential for heat production by means of solar thermal collectors. Among various types of solar collectors, evacuated tube solar collector (ETC) has attracted many attentions specially for the application in solar water heater systems (SWHs). However, due to the intermittence in solar intensity during the day, the ETCs may not work at their maximum functionality. There are number of studies investigating the effect of energy storage materials to eliminate the mismatch between supply and demand during peak hours. In the recent work of the authors, application of phase change materials (PCMs) integrated directly within the ETCs is studied experimentally. In this study, the computational fluid dynamics (CFD) modeling of heat pipe evacuated tube solar collector (HPETC) is performed. In order to cross-validate the obtained results to the recent experimental analysis, the boundary conditions are set as the real field-testing data. In the first part of the study, the 3D model of commercially available HPETC is simulated, while in the second part the HPETC integrated with the PCM is developed to analyze the improved thermal distribution. The selected type of PCM is Tritriacontane paraffin (C33H68), with a melting point of 72 °C and latent heat capacity of 256 kJ/kg. The simulation results show a acceptable agreement between the CFD modeling and the experimental data. The results from this study can be the benchmark for efficiency improvement of the ETCs in thermal energy storage systems.
Analysis of Structural Acoustic Design Variables for a Periodically Stiffened Plate Using the Finite Element Method
Authors: Blochberger Joseph A. 
Published: January 2020

Abstract
Investigating the acoustic radiation of stiffened plate structures is significant to the advancement of aircraft, automobile, and marine vehicle design. Plate and stiffener design variables affect how the global structure vibrates and radiates sound. The objective of this paper is to provide insight into how sensitive a periodically stiffened plate radiates sound in air with respect to its design variables.
This paper examines a clamped plate that is periodically stiffened along one direction. Finite element analysis is used to quantify the structural acoustic behavior of the plate subject to a harmonic point load at the plate’s center. Fourier transforms are performed along the plate’s surface to reveal the wavenumber content of the plate. Lastly, radiated sound power from the plate surface is computed.
A baseline plate without stiffeners is used for finite element modeling validation. Next, periodically spaced beams used for plate stiffening are inserted and varied in thickness. In addition, the plate thickness is also varied. Varying the plate thickness and the stiffener thickness provides insight to each design variable’s contribution to vibration and radiated sound power. The quantified findings from these parametric case studies serve as an insight into the structural acoustic performance of periodically stiffened structures.
Steam Turbine Axial Exhaust Diffuser Investigation Using a Test Rig and its Numerical Model
Authors: Kalista Robert , Mrózek Lukáš , Sláma Václav , Sedlák Kamil 
Published: January 2020

Abstract
Exhaust casings are one of the most important steam turbine components. The main purpose of the exhaust casing is to increase the last stage enthalpy drop, which results in an increase of the whole turbine output. It plays a significant role especially in turbines with lower outputs and in turbines whose condenser is cooled by air. In such cases, the exhaust casings with an axial diffuser is usually used. This paper deals with the investigation of the axial diffuser outlet part based on experimental measurements performed on a test rig installed in a wind tunnel in the Doosan Skoda Power laboratories and numerical simulations. The first part of the paper is about the general issues appearing the exhaust diffusers. Then, the design of the experimental test rig which aim is to simulate the flow conditions in real turbines is described. The last part of the paper is about experimental measurement as well as numerical results. The main observed phenomenon which is the effect of the circumferential angle on the inlet of the diffuser is described on different designs which were tested from the static pressure recovery factor point of view. For measuring flow parameters, a static wall pressure measurement was used together with multi-hole pneumatic probes. For numerical simulations, the commercial code ANSYS CFX 18.2 was used.
Performance of an Integrated Mild/Partial Gasification Combined (IMPGC) Cycle With Carbon Capture in Comparison With Other Power Systems
Authors: Long Henry A. , Wang Ting 
Published: January 2020

Abstract
With rising concerns about potential CO2 emissions and the effects of which on climate change and ocean acidification, it becomes necessary to consider developing newer and cleaner power plant technologies, including carbon capture. A conceptual clean coal technology called the Integrated Mild/Partial Gasification Combined (IMPGC) cycle implemented with a post-combustion carbon capture process is introduced in this paper. The IMPGC cycle employs mild gasification to preserve the high energy volatile matters within the coal and partial gasification to supplement the steam bottom cycle with a purely char-fired PC plant boiler. The performance of this newly conceptualized model is compared to those of other types of power plants, including natural gas combined cycle (NGCC), integrated gasification combined cycle (IGCC), and pulverized coal (PC) Rankine cycle plants under the condition that all plants utilize carbon capture in some form so as to achieve the same overall CO2 emissions as a high-performing NGCC plant. The results show that, while natural gas is still the top-performing power plant, IMPGC with carbon capture has the highest performance of all coal plants studied (∼39.7%), able to achieve the same CO2 emissions as natural gas, but with the same efficiency as a top-of-the-line subcritical Rankine cycle plant without carbon capture. This is about 2.5 percentage points better than an IGCC plant with carbon capture, ∼8 percentage points better than an ultra-supercritical Rankine cycle plant with carbon capture, and over 9 points better than a subcritical plant with carbon capture. This high performance is achieved through the use of a warm gas cleanup process based on the technology developed by RTI with the support of the U.S. Department of Energy.
Dynamic Characterization and Modeling of Flexure Based Planar Mechanism
Authors: Warnix Trevor , Tekes Ayse , McFall Kevin , Tekes Coskun 
Published: January 2020

Abstract
This paper investigates design, modeling and fabrication of a flexible five bar mechanism, which incorporates large deflecting flexure hinges attached to rigid links. This 3D printed flexible robotic mechanism is actuated by two servo motors and machine vision is used to obtain its tip position information. Detection of parts accomplished using color thresholding of a dynamic region of interest, while the position of detected elements is measured using the pinhole camera model. Under the assumption of non-small length flexures, where low aspect ratio is not satisfied, we adopt an initially curved pseudo rigid body approach to model each flexure as two rigid links that are pinned on top of each other using torsional springs, which capture the load-deflection behavior of the compliant flexures. Kinematic and dynamical equations are derived using both vector closure loop equations and Euler’s Laws of Motion. Adams simulation is performed by exporting the CAD model as a parasolid file, defining revolute joints and input motions and converting the rigid body to flexible. Mathematical model is validated using both the experimental data and Adams simulations.
Fracture Behavior of Cracked Ring Specimen at Different Crack Positions
Authors: Alqahtani Abdulmohsen M. , Albulayhid Thamer K. , Alotaibi Mutlaq N. , Alarifi Ibrahim M. , El-Bagory Tarek M. A. A. 
Published: January 2020

Abstract
The previous research review of piping systems revealed that the plastic pipes companies suffered from many problems in natural gas pipeline systems. One of the most significant problems appeared in the piping systems are external cracks due to manufacturing processes, welding technique and installation processes. The principal goal of the present experimental study is to predict the crack growth behavior and energy release rate of cracked ring specimen made from high-density polyethylene (HDPE) under different crack position angles and various crosshead speeds. The effect of loading rate on the external radial crack at different crack position angles plays an important role in the prediction of fracture behavior of plastic pipe materials. For this reasons, it is necessary to conduct a study for the fracture analysis of pipe ring specimen under tension loading with double external cracks at constant radial crack length to width ratio equal a/W = 0.5. Pre-cracking machine is designed especially in the present experimental study to simulate the actual radial cracks at outer surface of pipe ring specimens. The effects of crosshead speed and crack position angle are revealed a significant effect on the energy release rate and maximum applied load under tensile load.
Design, Modeling and Development of a Compliant Dual Resonator-Isolator
Authors: Jerkovic Boris , Rowell Abram , Ellis Nathan , Tekes Ayse 
Published: January 2020

Abstract
This paper investigates the construction, instrumentation, and dynamical modeling of a coupled three degrees of freedom compliant parallel arm mechanism. The compliant parallel arm, whose complete construction is carried out using 3D printing of polylactide (PLA) filaments, is a folded beam type mechanism, which is comprised of one primary and two secondary masses connected to two large deflecting beams. Dynamical model of the complete mechanism is obtained using Elastica Theory, where the large deflecting beams are considered as fixed-free cantilever beams subjected to a vertical tip load. Nonlinear load deflection curve, which is derived from the solutions of elliptical integrals, is approximated by a high-order polynomial function. Finally, the dynamics of the complete mechanism is derived using a classical lumped mass-spring-damper second order system. A linear actuator, PCB triaxial accelerometers, two laser displacement sensors and Arduino are utilized to gather acceleration and position information of each mass to identify the parameters of the lumped second order model using the offline Elastica Theory-based approach and polynomial fitting method. Numerical and experimental results verify the effectiveness of the proposed parameter identification schemes. Since system is nonlinear, state feedback linearization approach is adapted to linearize system equations at all operating points to control the trajectory of primary mass using a PID controller.
Numerical Investigation of an Academic Mistuned Bladed Disk Dynamics Accounting for Blade/Casing Contacts
Authors: Joachim Jeanne , Nyssen Florence , Batailly Alain 
Published: January 2020

Abstract
This contribution focuses on the combined analysis of mistuning and unilateral blade-tip/casing contacts. A 2D phenomenological finite element model of an aircraft engine fan stage is considered. It is reduced by means of the Craig-Bampton component mode synthesis method and contact treatment relies on a Lagrange multiplier algorithm within an explicit time-integration scheme. Blade-tip/casing contacts are initiated through the deformed shape of a perfectly rigid casing. Mistuning is accounted for on the blades only. Monte Carlo simulations are carried out in both linear and nonlinear configurations, which allows to compare amplifications predicted in both context due to mistuning. Following a thorough convergence analysis of the proposed numerical strategy, the influence of mistuning level as well as the configuration of the external forcing are investigated. Presented results underline the detrimental consequences of mistuning in a nonlinear structural context, yielding even higher vibration amplifications than in a linear context. A cross-analysis between linear and nonlinear computations reveals that no correlation is found between linear and nonlinear amplifications which suggests that the effect of existing strategies to mitigate vibration amplifications within a linear context may not be suitable within a nonlinear context.
Heating Conservation Methods and Economy Analysis of Winter Heating in Rural Residential Buildings in Southeast China: A Case Study
Authors: Tu Rang , Liu Mengdan , Liu Lanbin 
Published: January 2020

Abstract
In this paper, energy conservation approaches for residential buildings in rural area of southeast China are studied. There used to be no heating habits in rural buildings of southeast China, which is due to the relatively warm weather in winter. However, as the stand of living is increasing, heating in winter has become more popular in recent years. It is quite important to choose proper heating conservation materials taking both initial cost and operating cost into consideration. In this paper, a typical house in southern part of Henan Province is selected for study. It is a two-level house made of bricks, which was built in 2014. A set of radiators were installed for heating in winter. Water, which is heated by electrical heater, is used as heating medium for these radiators. As compared with heat pumps, draft sensation problem is avoided and temperature in the heating space is more uniform. However, operating fee is very high, which makes this heating method less attractive. To reduce power consumption of winter heating, heating load needs to be reduced and the efficiency of heating equipment needs to be increased. In this study, researches are carried out as following. First, a model is built in DeST, which is a software that can calculate hourly heating load and room temperature. Then, the effect of thermal preservation quality of envelops on room temperature and heating load are investigated. Six models with different envelopes are simulated. Then, heating load as well as power consumptions of electrical heaters and heat pumps among the six envelopes are compared. Lastly, economic analysis is carried out for the energy efficient retrofit case so that the payback period is calculated. The results show that heating load capacity of case F, envelope of which made of 240 bricks plus foamed plastic and hollow glass windows, can be reduced to 1/3 that of case A, envelope of which made of 240 bricks and single glass windows. Considering power consumptions of both compressors and fans, energy consumption density (divided by area) can be reduced from 21.6∼25 kWh·m−2·year−1 of case A, which has the worst heat conservation property, to 6.7∼7.7 kWh·m−2·year−1 of case F. If the building is improved from case A to case F and heat pumps are adopted, the payback period is 3.3∼3.8 years. Because of high cost of window retrofit and small influence of its heat conservation property on the reduction of heating capacity, it is recommended to just improve walls. Air tightness of window is more effective than thermal quality.
Numerical and Experimental Analysis of Attaching-Mandrel Process Under Multi-Pass Cold Spinning Process on Superalloy GH3030
Authors: Zixuan Li , Xuedao Shu , Zewei Cen , Song Zhang 
Published: January 2020

Abstract
The superalloy products formed by multi-pass conventional spinning are widely used in rotary forming parts with complex shapes. As the connection of each forming pass, the attaching-mandrel process has an important influence on forming quality and production efficiency. The hot spinning process is usually adopted in superalloy forming because its poor plasticity in normal temperature, meanwhile, it brings the poor surface quality of the parts and huge energy consumption. For this reason, the cold spinning and the attaching-mandrel process of nickel-base superalloy GH3030 are studied. The combination method of experiment and simulation is used to study the attaching-mandrel process based on one-forward-pass spinning process. The effects of pass pitch and the attaching-mandrel velocity on the tool forces, parts stress field, strain field and wall thickness distribution are analyzed. The microstructure of the part is divided into three layers: outer, middle and inner layer. The grain size of each layer is compared. Then the effect of different pass pitch on the grain structure is clarified. The results show that the reasonable pass pitch and the attaching-mandrel velocity can improve the forming quality and production efficiency. The multi-pass cold spinning process on superalloy GH3030 is feasible. The excessive pass pitch can cause seriously grain elongation, the grain boundaries are blurred, and even cracking.
Numerical Investigation of the Dropwise Condensation Process in Top of the Line Corrosion
Authors: Mohamed Ibrahim E. , Thompson Harvey M. , Barker Richard 
Published: January 2020

Abstract
Many approaches have been used for modelling Top of Line Corrosion (TLC) however there are a large discrepancies between their results. One common assumption is that TLC is limited by the amount of iron that can be transported with the condensed water. This means that the TLC rate is proportional to the water condensation rate and the iron solubility in the condensed phase. Therefore, a theoretical investigation is performed into the effects of gas inlet conditions on the water condensation rate in wet gas pipeline using Fluent. Comparisons were drawn with the semi-analytical model of Zhang et al. and CFD results showing good agreement between the two. The numerical results obtained reveal quantitatively how an increased inlet gas pressure leads to reductions in the condensation rate. While increasing inlet gas temperature and velocity lead to increases in condensation rate.
A Secure Cyber-Manufacturing System Augmented by the Blockchain
Authors: Song Jinwoo , Moon Young B. 
Published: January 2020

Abstract
Cyber-Manufacturing System (CMS) is an innovative factory of the future, where manufacturing information is being constantly exchanged among many entities through various computer networks including the Internet. However, CMS ushers in the unique security challenges from the sheer volume and pervasiveness of exchanged data, and increased accessibility of the system by its outsiders and insiders. Also, the connections among the physical components can reveal accessible routes into the system.
This research presents a unique approach to secure CMS augmented by a Blockchain. The secure Cyber-Manufacturing System with Blockchain consists of four layers: User layer, Provider layer, Service layer, and Blockchain layer. To validate how the system enables safe communications in CMS, auditing physical data through the private blockchain was experimented on a CMS testbed. The results of three different physical data audits are compared; the system’s effectiveness is demonstrated.
Boundary Integral Equations Method in the Coupled Theory of Thermoelasticity for Porous Materials
Authors: Svanadze Merab 
Published: January 2020

Abstract
This paper concerns with the coupled linear theory of thermoelasticity for porous materials and the coupled phenomena of the concepts of Darcy’s law and the volume fraction is considered. The system of governing equations based on the equations of motion, the constitutive equations, the equation of fluid mass conservation, Darcy’s law for porous materials, Fourier’s law of heat conduction and the heat transfer equation. The system of general governing equations is expressed in terms of the displacement vector field, the change of volume fraction of pores, the change of fluid pressure in pore network and the variation of temperature of porous material. The fundamental solution of the system of steady vibration equations is constructed explicitly by means of elementary functions and its basic properties are presented. The basic internal and external boundary value problems (BVPs) of steady vibrations are formulated and on the basis of Green’s identities the uniqueness theorems for the regular (classical) solutions of the BVPs are proved. The surface (single-layer and double-layer) and volume potentials are constructed and their basic properties are established. Finally, the existence theorems for classical solutions of the BVPs of steady vibrations are proved by means of the boundary integral equations method (potential method) and the theory of singular integral equations.