bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study on the Internal Separated and Inverse Flow Between the Blades
Authors: Furuta Hiroki , Terashima Osamu , Sakai Yasuhiko , Nagata Kouji , Ishiguro Shunsuke , Sakai Masaharu , Ito Yasumasa 
Published: April 2014

The objective of this study is to investigate an internal separated flow between the blades of turbo machinery. Flow separation often causes undesirable phenomena such as an increase of the total pressure loss and a vibration of the machine. Therefore, understanding the characteristics of the separated flow in detail is very important for optimizing the machine to decrease the energy loss.
In general, the separated flow involves a reverse flow near the solid wall in the separation bubble and its reattachment of the further downstream location. Hence, a typical hot-wire sensor is not useful for measuring the internal separated flow between the blades because it can detect only the magnitude of the flow velocity, not the flow direction.
Based on this background, a self-developed tandem-type hot-wire sensor, by which both the magnitude and the flow direction can be detected, is used to measure the velocity field between the blades in this study. The tandem-type hot-wire sensor consists of two I-type hot-wire sensors and a small insulated elliptical cylinder placed between them. A calibration test is first conducted to validate its performance.
Subsequently, the separated flow between the blades is measured with the tandem-type hot-wire sensor. The experimental apparatus consists of a closed-type test section which is connected to the nozzle exit of a blowout-type wind tunnel. In this test section, a sample of blade is set up. In this study, experiments are conducted with three kinds of blades with the different shapes (i.e., experiments are performed under three different conditions): a constant blade thickness from the leading edge to the trailing edge (Blade 1), a constant blade thickness from the leading edge to trailing edge but a rounded leading edge (Blade 2) and a thin blade thickness at the leading and trailing edges (Blade 3).
In addition, the unsteady internal separated flow between the blades is also investigated by large-eddy simulation (LES) whose validity was fully confirmed in the previous study. The flow field and dissipation rate of the turbulent kinetic energy obtained by the simulation are discussed.
Experimental and numerical results show that Blade 3 has a smallest separation bubble around the leading edge than that of Blade 1 and 2, and shows a smallest root mean square (RMS) value for the velocity fluctuation near the reattachment point than them. These differences of the size of separation bubble and velocity fluctuation were considered to be resulted in a decrease of the kinetic energy loss in the test section with Blade 3. Therefore, it can be concluded that the non-uniform thickness of the blade causes the decrease of the energy loss around the blade.
A Comparative Study of Mechanical Properties of Tooth Reconstruction Materials
Authors: Chun Keyoung Jin , Choi Hyun Ho , Lee Jong Yeop 
Published: April 2014

Tooth reconstruction materials are used to reconstruct damaged teeth as well as to recover their functions. In this study, the mechanical properties of various tooth reconstruction materials were determined using test specimens of identical shape and dimension under the same compressive test condition; the hardness values of them were obtained from previous studies and compared with those of enamel and dentin.
Amalgam, dental ceramic, dental gold alloy, dental resin, zirconia and titanium were processed as tooth reconstruction material specimens. For each material, 10 specimens having a of 3.0 × 1.2 × 1.2 mm (length × width × height) were used.
The stresses, strains, and elastic moduli of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were obtained from the compressive test. The hardness values of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were obtained from the references [14–19].
And, the stresses, strains, elastic moduli, and the hardness values of enamel and dentin were obtained from the reference [13].
The mechanical role of enamel is to crush food and protect dentin because of its higher wear resistance, and that of dentin is to absorb bite forces because of its higher force resistance. Therefore, the hardness value should be prioritized for enamel replacement materials, and mechanical properties should be prioritized for dentin replacement materials. Therefore, zirconia and titanium alloy were considered suitable tooth reconstruction materials for replacing enamel, and gold alloy, zirconia, and titanium alloy were considered suitable tooth reconstruction materials for replacing dentin. However, owing to the excessive mechanical properties and hardness values of zirconia and titanium alloy, these may show poor biocompatibility with natural teeth.
Thus far, no tooth reconstruction material satisfies the requirements of having both a hardness value similar to that of enamel and mechanical properties similar to those of dentin.
Preliminary Analysis of SGTR Accident for an Integral Effect Test Facility, SMART-ITL
Authors: Kim H. K. , Chung Y. J. , Kim S. H. , Kim H. S. 
Published: April 2014

SMART-ITL (system-integrated modular advanced reactor-integral test loop) has been built at Korea Atomic Energy Research Institute (KAERI) in order to validate the safety and performance of SMART. It is an integral effect test facility and its scale is 1/1 in height and 1/49 in volume with respect to SMART plant. The objectives of SMART-ITL are to investigate and understand the integral performance of reactor systems and components and the thermal-hydraulic phenomena occurred in the system during normal, abnormal and emergency conditions, and to verify the system safety during various design basis events of SMART. The integral-effect test data will also be used to validate the related thermal-hydraulic models of the safety analysis code such as TASS/SMR-S, which is used for performance and accident analysis of SMART design.
SMART with a rated thermal power of 330 MWt has been developed at KAERI. SMART is an integral type pressurized water reactor with a mixture of the proven technologies and advanced design features. The enhancement of safety is realized by incorporating inherent safety features and passive safety systems. The licensing has been approved by the Korean nuclear regulatory authority in 2012. TASS/SMR-S code can analyze thermal hydraulic phenomena of SMART in a full range of reactor operating and accident conditions. A steam generator tube rupture (SGTR) accident is one of the safety related design basis events and should be analyzed with thermal hydraulic and radiological viewpoint. A preliminary analysis of an SGTR accident for SMART-ITL was performed using TASS/SMR-S code to setup test procedure.
The thermal-hydraulic analysis for SMART-ITL SGTR accident with the geometrical, thermal-hydraulic parameters and modeling information was performed. The major concern of this analysis was to find the thermal-hydraulic phenomena and maximum leakage amount from a primary to a secondary side caused by an SGTR accident. The result was also compared with the result of SMART SGTR accident analysis. In spite of the different assumptions and scaling, the compared results are reasonable. The characteristics of SMART SGTR accident are well reflected on SMART-ITL. The analysis result of preliminary SMART-ITL SGTR accident estimates the major effects of SMART SGTR accident successfully.
Periodicities Changes of Nonlinear Oscillatory Behavior of a Fluttering Plate With Periodicity Ratio and Periodicity Change Rate
Authors: Dai Liming , Han Lu 
Published: April 2014

This study focuses on diagnosing the periodicity change of nonlinear dynamic responses of a fluttering plate excited by high-velocity air flow. The number and changing multiple-periodicities of the system with the implementation of Periodicity Ratio (PR) are investigated. The multiple-periodicity diagram is generated such that the periodicities and nonlinearity of the systems with respect to the system parameters can be graphically studied.
The results of the research show that the number of period of periodicity of the systems increases when certain system parameters increase. Transitional characteristics of the systems are also investigated with Periodicity Change Rate as well.
Preliminary Investigation of a Liquid Desiccant System for Dehumidification and Cooling in Athens
Authors: Koronaki I. P. , Christodoulaki R. I. , Papaefthimiou V. D. , Rogdakis E. D. 
Published: April 2014

Liquid desiccant air conditioning systems have recently been attracting attention due to their capability of handling the latent load without super-cooling and then reheating, as happens in the conventional compression-type air conditioning systems. In liquid desiccant cooling cycles, a sorbent solution is employed to dehumidify the air, circulating between the two critical components; the dehumidifier and the regenerator. As the strong desiccant solution is sprayed on top of the internally cooled dehumidifier, it flows down by gravity and comes in contact with the process air. The desiccant solution which, by definition, has a strong affinity for water vapor absorbs moisture from the air. The end of the process finds the air cool and dehumidified and the solution diluted. The diluted desiccant solution enters the regenerator in order to retrieve its initial concentration. Hot water derived from a low temperature source supplies the necessary heat to the solution and the excessive water content is evaporated. At the end of the process, the hot humid air is rejected to the ambient and the concentrated solution is driven to the dehumidifier.
The complex heat and mass transfer phenomena, occurring both in the dehumidifier and regenerator, has been the subject of earlier work by the authors. Based on the knowledge gained, a liquid desiccant system was installed at the National Technical University of Athens, Laboratory of Applied Thermodynamics, for experimental purposes. The liquid desiccant system was constructed by the German company L-DCS [1].
The main components of the system are the dehumidifier, the regenerator and the evaporative cooler. The system uses water as the cooling medium and LiCl solution as the desiccant. It also employs two storage tanks, one for the concentrated solution and one for the diluted. The purpose of this publication is to present the newly installed liquid desiccant system, to predict the performance of the dehumidifier and to carry out preliminary design optimization.
Experimental Study of a Roll-Plane Hydraulically Interconnected Suspension System Under Vehicle Articulation Mode
Authors: Xu Guangzhong , Roser Holger M. , Zhang Nong 
Published: April 2014

This paper presents a detailed experimental study to quantitatively assess the performance of a roll-plane Hydraulically Interconnected Suspension (HIS) system in articulation (warp) mode. This mode is critical for better off-road vehicle handling, particularly in utility vehicles. Articulation of a four-wheel vehicle describes the in-phase motion of two diagonally opposed wheels, with adjacent wheels moving out of phase.
The widely used anti-roll bars, required for increased roll resistance, also stiffen the articulation mode, which may result in one or more wheels losing ground contact on uneven surfaces, compromising vehicle stability and safety. Yet roll-plane HIS systems are capable of decoupling vehicle roll from articulation.
A comparative experimental analysis of HIS and conventional anti-roll bars has been conducted to evaluate vehicle dynamic performance at full-car level under articulation excitation. Test results demonstrate that the HIS system has a negligible effect on wheel travel in articulation mode, offering a significant improvement in vehicle handling and safety over conventional anti-roll bars.
Analysis and Simulation of an Oil Lubrication Pump for the Internal Combustion Engine
Authors: Senatore Adolfo , Buono Dario , Frosina Emma , Santato Luca 
Published: April 2014

This paper presents the simulation model of an oil lubrication gerotor pump for the internal combustion engine.
The model was constructed by using a mono-dimensional commercial code taking into account all the phenomena that occur during the revolution of the pump shaft. First of all, several geometric considerations and theoretical observation are presented.
An experimental campaign was also performed to validate the simulation model. In these experimental tests particular attention was regarded to the behavior of the pressure oscillations during the pump shaft revolutions.
The final aim of this activity is to obtain an instrument that allows in-depth analysis of pump and lubrication circuit functioning and that can be coupled with other models (e.g. VVA, VVT, etc.) in order to take into account different problems of the hydraulic components of engines.
Implementation of a Nonlinear Torsional Vibration Absorber for Suppression of Vibrations in Rotating Machinery
Authors: Tahir Ammaar Bin , Shiryayev Oleg , Vahdati Nader , Karki Hamad 
Published: April 2014

Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is tuned for a specific resonant frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies. Vibrations dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system.
Experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, we carry out the design optimization of the nonlinear torsional vibration absorber using an equivalent 2-DOF modal model. A linear vibration absorber is developed in parallel. Subsequently, both absorbers will be manufactured, assembled and mounted on the system to evaluate their vibration suppression capabilities.
Optimization of Heat-Sink Fin Features by FEA Simulation
Authors: Wen Jing Heng , Neely Michael J. 
Published: April 2014

Heat sinks are frequently used when heat exchange is required for electric circuits. In cases where the heat generation is evenly distributed, the height and spacing of fins are uniform. However, when heat generation is locally concentrated, uniform fin distribution is not the most efficient design.
The original battery-charger heat-sink for a particular model of electric golf car featured a uniform fin design that had been in use for a long time. When re-tooling was required, the design team decided to investigate the heat-sink design for potential improvement.
The project began by analyzing the heat-flow distribution of the baseline design. It was found that approximately 70% of the total heat flow was concentrated at a local area. The efficiency of the heat sink was based on material thermal property, fin height, fin spacing and etc. ANSYS thermal and structure were used to optimize these features.
In order to understand how fin height and spacing influenced heat exchange, a three-step optimization process was used, including fin spacing optimization, fin height optimization and a combining analysis. The working environment was assumed to be non-forced convective cooling. The final design featured a highly non-uniform fin distribution that improved heat exchange by approximately 10% with a material reduction of about 15% compared with the baseline design. A US patent is pending for the improved heat-sink design.
Flow Analysis on Piping Networks Using the Finite Element Method
Authors: Moreno Carlos Luis 
Published: April 2014

The objective of this work is to apply the Finite Element Methodology (F.E.M.) to several piping systems, using an incompressible working fluid, in order to calculate the volumetric flow on each element and the piezometric load on each node of the network. To accomplish this goal a computational code was designed using Fortran Computational Language. Such a code consists of a main program and six subroutines. The input variables are general data of the network including the number of pipes, the number of nodes, the piezometric load values on nodes where they are constant (tanks for example), demanding flows in those nodes where the fluid is removed from the system, a connectivity table indicating the assumed flow direction in each pipe, and the number of pumps with respective parabolic curve coefficients. Program data also included both the maximum number of iterations and tolerance allowed. Fluid properties such as kinematic viscosity, density and pipe features such as length, diameter and absolute rugosity are also required. The output data include pipe volumetric flows and piezometric load on variable static pressure nodes.
In this work, three different network systems were analyzed: 51-, 63- and 65-element networks. All were examples taken from the bibliography. The Finite Element Methodology results were first validated with real data, and then compared with the other results coming from the Hardy-Cross, Newton-Raphson and Linear Methods. The comparison was based on convergence speed and numerical stability. It is concluded that the methodology called Finite Element Methodology requires a smaller number of iterations than the Hardy-Cross, Linear and Newton-Raphson Methods. Another advantage of the Finite Element Methodology is that there is no need to assign the flow initial values that satisfy the Continuity Equation on each node of the piping network before running the program. Also, no loops establishing is needed. In addition, the designed code permits calculations for networks that present both booster and feed pumps. The importance of this work rests on the fact that nowadays it is necessary for piping network flow analysis to use computational simulation in order to design systems more efficiently and economically. Furthermore, this work is important for network construction as well as the satisfaction of consumer demand on a local community level, taking into account prevailing normative requirements. This paper, consequently, aims to contribute to progress in these areas.
Design and Structure Analysis of Wheeled Chassis With Self-Balancing Rocker of Rescue Engineering Machinery
Authors: Xu Guoyan , Wang Xiaopo , Gao Feng , Xie Xiaolin , Ding Nenggen 
Published: April 2014

A wheeled chassis with self-balancing rocker is developed for rescue engineering machinery. This chassis has better ground adaptability compared with traditional ones because of the automatically adjustable ground clearance and body posture, non-trapezium steering mechanism, independent four-wheel steering, and “X”-type radiation legs.
Finite element analysis on the chassis structure is done with two mechanical models and under typical finite element working conditions. HyperWorks software is used to analyze different parts of the chassis, and the results are used for structure optimization. The rocker plate thickness and rocker frame topology are optimized using Optistruct. The results demonstrate the effectiveness and feasibility of proposed optimization methods.
A Simple Flexible Plate for Usage as Force Sensor Element With Constant Stiffness
Authors: Ottnad Thomas , Lüßmann Henrik , Lueth Tim C. 
Published: April 2014

Control of pressure is one of the most decisive parameters influencing the quality and reproducibility of products when dealing with plastics producing techniques such as injection molding, extrusion, and related techniques. For that purpose different types of pressure sensors for specific tasks come into action. Different tasks can be different working pressure ranges, static or dynamic pressure, working temperatures and requirements concerning the environment. Therefore different types of pressure sensors are commonly used which most often transform mechanical deformation into electrical signals and these in turn are converted into the value of pressure. This in turn can mean extensive effort for installation and insulation of the pressure sensors.
An approach to design a pressure sensor based solely on its mechanical deformation is basic idea of the present work. The pressure sensor consists of a flexible element which is in fact a thin plate with a ram on its outer side and can be clamped easily at any desired area on a melt channel. When being applied to pressure the working pressure causes a deflection of the flexible element. Measuring this deflection and knowing the mechanical behavior of the flexible element allows the calculation of the value of pressure.
To get to know to the mechanical behavior, especially the stiffness, of the flexible element a test rig was designed and refined. In the test rig as substitution of the pressure variable but defined load can be applied using a piezo-electrical actuator with integrated position sensor. Measuring the applied force using a force sensor and measuring the resulting deflection of the flexible element using a length gauge allows to calculate the stiffness of the flexible element. Regarding the flexible element as Kirchhoff plate a constant stiffness is expected and this could be proven taking measurements.
When taking a look at the deflection of the piezo-electrical actuator and the flexible element there is a difference due to the elasticity of the test rig itself. When determining the stiffness of the test rig a non-constant stiffness was detected which was not expected. Reason for that is the non-constant stiffness of the used force sensor though stated other by the manufacturer. This could be proven substituting the force sensor with the flexible element. With that the flexible element showed to be appropriate to be used as force sensor with a constant stiffness.