bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stepwise Comparison of Expert and Nonexpert Preparations of a Polished Metallographic Surface
Authors: Sugimoto Takuya , Sakamoto Toshihiko , Kuwahara Yoshiaki , Koshino Tetsushi , Endo Atsushi , Takai Yuka , Goto Akihiko 
Published: April 2014

The carburizing process requires metallurgical inspection by means of polished metallurgical mounts. Metallographic preparation for a metallurgical mount is an important process. The purpose of this study is to clarify the differences in ground and polished surface finishes of metallurgical mounts for carburized parts at each step of the process as executed by an expert and a nonexpert on a semi-automated grinding and polishing machine.
To clarify the differences between expert and nonexpert preparations, microscopic images of the surface finish obtained at each step of grinding and polishing were compared. The surface profile of each of the final finishes was also examined with measuring device. Each inspector has either 20 (expert) or 0.5 years (nonexpert) of experience in metallographic preparation. The ground and polished finish produced by the expert was well balanced over the entire surface. In contrast, the surface finish produced by the nonexpert was dispersed. The number of scratches and edge rounding depth apparent in the final surface finish of the expert were less than those of the nonexpert.
Multidimensional Thermal-Hydraulic Analysis on Natural Circulation Behavior in Ex-Vessel Fuel Storage Tank of MONJU
Authors: Ohno Jun , Mori Takero , Sotsu Masutake , Ohira Hiroaki 
Published: April 2014

Since the accident of the Fukushima Dai-ichi Nuclear Power Station, analysis evaluations for stress tests have been conducted on the prototype fast breed reactor MONJU. In these evaluations, it has been necessary to evaluate the plant characteristics including the Ex-Vessel fuel Storage Tank (EVST) under the severe accident conditions such as station blackout. The EVST is a coaxial cylindrical tank to store spent fuels (SFs) stored in fuel transfer pots (FTPs) until the radioactivity enough decays. It is able to store 252 fuel transfer pots in the rotating rack and cool them by internal natural circulation of sodium coolant under both the severe accident and normal operation. The heat produced by SFs removed by the helical cooling coils installed in the annular space.
Evaluations of natural circulation in the EVST have been performed with a one-dimensional flow-network code. However, it would be difficult to predict its behavior exactly, because it would include multidimensional flow such as local natural convection. Then, in order to clarify the natural circulation behavior and multidimensional effects and evaluate appropriateness of this flow network model, we have performed a thermal-hydraulic analysis using a three-dimensional model which has high resolution meshes and the almost same geometry as the actual equipment. This model makes it possible to take into account the following multidimensional phenomena, the heat distribution of the FTPs, the mixing in plenums, the bypass flow through the flow holes and the other geometry effects.
In this study, we have used a commercial computational thermal-hydraulics code, “FrontFlow/red”. As a result of steady analyses, we have confirmed the following: The coolant temperature in the plenums is almost uniform and its difference is in a few degrees. The influence of the flow holes is also limited because its flow rate is relatively low to main flow rate. On the other hand, pressure loss at supporting plates of the rotating rack, which are main causes of flow resistance in the EVST, is larger than the case without multidimensional effects because of the natural convection concentrated in the high temperature region near heated FTPs. The result leads to our presumption that the flow network model of the EVST is almost appropriate. It should be noted that flow resistance coefficient of the supporting plates or the heat transfer center of the cooling coils should be set to conservative for the safety analysis on the EVST.
Dynamic Performance Simulation of an Aeroderivative Gas Turbine Using the Matlab Simulink Environment
Authors: Tsoutsanis Elias , Meskin Nader , Benammar Mohieddine , Khorasani Khashayar 
Published: April 2014

In fossil fuel applications, such as air transportation and power generation systems, gas turbine is the prime mover which governs the aircraft’s propulsive and the plant’s thermal efficiency, respectively. Therefore, an accurate engine performance simulation has a significant impact on the operation and maintenance of gas turbines as far as reliability and availability considerations are concerned. Current trends in achieving stable engine operation, reliable fault diagnosis and prognosis requirements do motivate the development and implementation of real-time dynamic simulators for gas turbines that are sufficiently complex, highly nonlinear, have high fidelity and include fast response modules.
This paper presents a gas turbine performance model for predicting the transient dynamic behavior of an aeroderivative engine that is suitable for both mechanical drive and power generation applications. The engine model has been developed in the Matlab/Simulink environment and combines both the inter-component volume and the constant mass flow methods. Dynamic equations of the mass momentum and the energy balance are incorporated into the steady state thermodynamic equations. This allows one to represent the engine model by a set of first order differential and algebraic equations. The developed Simulink model in an object oriented environment, can be easily adapted to any kind of gas turbine configuration. The model consists of a number of subsystems for representing the gas turbine’s components and the thermodynamic relationships among them. The components are represented by a set of suitable performance maps that are available from the open literature.
The engine model has been validated with an established gas turbine performance simulation software. Time responses of the main variables that describe the gas turbine dynamic behavior are also included. The proposed gas turbine model with its dynamic simulation characteristics is a useful tool for development of real-time model-based diagnostics and prognostics technologies.
A Two-Feet Linear Ultrasonic Motor for Fuze Safety System
Authors: Tang Y. J. , Wang J. 
Published: April 2014

In modern weapons systems, fuze is known as the “brain” of the ammunition, whose performance will directly affect the combat effectiveness. It guarantees the safety of ammunition during the logistical processing and makes the ammunition reliably function after launch. In the fuze system, the delay arming device is closely related to the fuze performance and safety reliability, which affects the muzzle safety distance. After years of development, the performance of delay arming device has been developed and improved, but malignant accidents such as explode in the chamber, early burst and dud have occurred from time to time.
This paper investigated a standing wave linear ultrasonic motor applied to the fuze delay arming device as the arming actuator. The motor is made up of a cuboid with two drive feet and a slider with a convex part, both having a through hole. The first order longitudinal vibration and second order bending vibration of the stator were selected as working modes. The prototype was fabricated and the vibration mode test was carried out, indicating the motor can generate two-phase required oscillation modes. The frequency sweep test was also performed and two-phase frequency is proved quite close. The experiments on the motor mechanical performance were done, and the speed of the motor is 88.2 mm/s, furthermore the reciprocating motion of the slider is flexible.
Magnetic Field Enhancement in Water-Lithium Bromide Absorption Refrigeration Systems
Authors: Odunfa K. M. , Fagbenle R. O. , Oyewola M. O. 
Published: April 2014

Absorption refrigeration systems are generally characterized by low Coefficient of Performance (COP). Absorption enhancement is an effective way of improving the COP of refrigeration systems. Literature is sparse on the use of magnetic field for the enhancement of absorption refrigeration systems despite its cheapness and environmental friendliness as compared with other enhancement methods. Although the method has recently been employed on ammonia solution, its influence on lithium bromide (LiBr) solution is yet to be fully studied. In this paper a numerical model for the magnetic field enhancement in water-LiBr absorption systems was developed and evaluated.
The flow within the film thickness to the absorber wall was considered as a two-dimensional steady laminar flow. A Finite Difference model was developed based on conservation of mass, momentum, energy equations and mass transport relationship. The model was validated using data from the literature on ammonia solution. Standard parameters including absorber wall length (1 m), film thickness (10–3 m), magnetic field vacuum permeability (1.257 × 10–6 kgmA-2s2), magnetic mass susceptibilities and magnetic induction intensities were used for LiBr solution’ modeling. Changes in their concentrations, both in the direction of falling film and across its thickness, were investigated. Data were analysed using descriptive statistics and Student’s t-test (p = 0.05).
The concentration distribution of lithium bromide solution in the direction of falling film was between 54.9% and 60.0% for the magnetic induction range of 0.0 and 3.0 Tesla. Across the film thickness and for the same range of magnetic induction, the concentration distribution was between 0.0 and 0.19. The concentration of the solution increased from 0.0 to 21.7 when magnetic induction was increased from 0.0 to 3.0 Tesla, implying higher cooling effect. The COP of lithium bromide solution absorption refrigeration system was increased by 0.3% for magnetic induction of 3.0 Tesla.
Magnetic field enhanced the absorption performance in the lithium bromide solution; hence can be used in typical absorption refrigeration systems.
Comparison of Dynamic and Aerodynamic Characteristics of the Centrifugal Fan Calculated by Different Methods
Authors: Gášpár Roman , Kalmár László , Polanský Jiří 
Published: April 2014

The main aim of this paper is determine the centrifugal fan with forward curved blades aerodynamic characteristics based on numerical modeling. Three variants of geometry were investigated. The first, basic “A” variant contains 12 blades. The geometry of second “B” variant contains 12 blades and 12 semi-blades with optimal length [1]. The third, control variant “C” contains 24 blades without semi-blades. Numerical calculations were performed by CFD Ansys and OpenFoam.
Another aim of this paper is to compare results of the numerical simulation with results of approximate numerical procedure. Applied approximate numerical procedure [2] is designated for to determine characteristics of the turbulent flow in the bladed space of a centrifugal-flow fan impeller. This numerical method is an extension of the hydro-dynamical cascade theory for incompressible and inviscid fluid flow. Paper also partially compares results from the numerical simulation and results from the experimental investigation. Acoustic phenomena observed during experiment, during numerical simulation manifested as deterioration of the calculation stability, residuals oscillation and thus also as a flow field oscillation. Pressure pulsations are evaluated by using of frequency analysis for the each variant and working condition.
Detection of Subsurface Skin Lesion Using Frequency Modulated Thermal Wave Imaging: A Numerical Study
Authors: Bhowmik Arka , Repaka Ramjee , Mishra Subhash C. , Mulaveesala Ravibabu 
Published: April 2014

Infrared thermography is one of the promising and non-invasive imaging approaches which can be performed either in passive or in active mode. Due to its inherent capabilities, viz., fast, safe and subsurface feature extraction, this technique has been widely used in bio-medical imaging. In conventional passive approach, imaging may not provide enough contrast for detection of subsurface skin lesion. However, this limitation can be surmounted by using active thermography technique in which controlled energy is being supplied to the skin. This controlled stimulus not only helps in the detection of deeper subsurface details but also helps in getting the quantitative information of hidden features. Apart from the various widely used active approaches such as modulated lock-in thermography (LT) and high peak power pulsed based thermography (Pulsed Thermography - PT and Pulse Phase Thermography - PPT) techniques, the present article highlights an alternative approach which can be performed in less time as compared to LT and with much less peak powers as compared to pulsed based thermography (PT and PPT) techniques.
The present work utilizes a non-stationary thermal wave imaging approach to map the subsurface skin lesion. The multilayered skin has been modeled and simulated for a given frequency modulated heat stimulus using 3-dimensional bio-heat equation.
Dynamic Classification: A Tool for Fault Detection and Vibration Behavior Monitoring of Bearings
Authors: Kerroumi Sanaa , Rasolofondraibe Lanto , Chiementin Xavier 
Published: April 2014

The emergence of a defect in a mechanical system is always associated with a change in the vibration’s behavior in the spectral and temporal domains. Fault detection by vibration analysis is based on monitoring the behavior of a mechanical component by examining the evolution of fault indicators in real time. However, mere traditional bearing diagnosis is not sufficient to ensure effective and reliable assessment of the component’s health condition. Coupling several fault indicators extracted by different signal processing technique adds more reliability and accuracy to the diagnostic process.
Classifications methods are used to analyze the evolution of fault, yet only static methods are solicited which results in overlooking a great source of useful information.
In fact, fault indicators issued from turning machine are evolving; they change constantly over time, particularly when the defect is growing. In such situations, static classification methods are a poor choice that deprives the user of the information conveyed in the evolution of the indicators over time.
The dynamic classification of fault indicators in dynamic classes can provide useful information about the behavior of the damaged bearings. This information can also be used to predict the end of life of the components.
Unlike the static classification, the dynamic classification introduces a new dimension (time), which allows real-time detection of the fault and better visibility of the bearing behavior revealed by the motion and the temporal evolution of classes formed by the indicators.
This paper proposes a dynamic classification method that uses several fault detectors to assure the accuracy of the diagnostic and follow up any changing in the behavior of the bearing by analyzing the classes’ time evolution.
The proposed multi-features dynamic classification is a new method for fault detection and health condition monitoring for bearings; this technique utilizes multiple features, including traditional features extracted from the raw signal, two special features extracted by wavelet analysis, and the spectral kurtosis, coupled with a nonlinear principal component analysis.
This method of classification clusters the multi-features into several classes, the first class represents the healthy state of the bearing, and the other classes represent different damaging state. Monitoring the evolution of the” defective condition” class allows us to draw several useful information, such as the rate of degradation, the relationship between the cluster’ surface and density and the bearing state.
The chosen dynamic classification method will be validated by analyzing several degradation bearings from a fatigue bench of thrust ball bearings SNR51207.
Development of High Stiffness Axle for a Race Vehicle
Authors: Jung Jin Ho , Lim Dong Min , Lee Jae Kil , Kim Seon Pyung 
Published: April 2014

In rallies, it is required to develop the high stiffness and high strength suspension parts in order to maximize the handling performance and reliability to severe race condition. To determine which part we should focus on among the suspension parts in the development stage, it is required to consider the driving condition and the various rally road conditions.
First, it is necessary to increase the lateral stiffness and camber stiffness of suspension systems in order to maximize the handling and cornering performance. As the result of finite element (FE) analysis for production car suspension, it is verified that the stiffness of axle assembly affects mainly on the lateral stiffness of suspension system. Second, the shock loads under severe conditions such as landing after jump and bumpy road and the driving and braking torque are concentrated on the axle assembly. As the result of above consideration, developing the high stiffness and high strength axle has been considered as the most important work for the project of rally car suspension development.
For the development of new prototype car, hub and upright have been newly developed and new big bore wheel bearing has been selected in order to increase the stiffness of axle assembly. Newly developed suspension components have been installed in the new prototype car and 3 different test cars have been introduced to verify the effect of high stiffness axle.
Finally, Kinematic and Compliance (K&C) test result for these 3 test cars shows that the stiffness of axle assembly is the most significant parameter to increase the lateral stiffness of whole suspension system.
Insights on Centrifugal Pendulum Vibration Absorber: Part One — Dynamic Modeling and Behaviour of Eigenvalues and Eigenvectors Along Rotating Speed
Authors: Simionatto Vinícius G. S. , Miyasato Hugo H. , Dias Júnior Milton 
Published: April 2014

An automotive powertrain is a system that is designed to transmit torque from the engine to the wheels of the vehicle, allowing it to move. The working principle of most of the vehicle engines is the internal combustion, which causes the torque generated by this engine to have important oscillatory components, which cause the powertrain to vibrate and generate noise, which is undesired.
In order to control this vibration, among many engineering solutions is the centrifugal pendulum vibration absorber (CPVA), whose dynamic behaviour turns it is capable of reducing the amplitude of important order components of the powertrain. It is usually installed on the flywheel of the vehicle, although it is possible to install it in other parts, such as the clutch disk.
Although the CPVA is an important type of passive vibration absorber, it was still not found in the literature a parametrized formulation which can be applied to any vibration absorber of this kind. For this reason, the aim of this work is to propose a formulation based on dimensionless parameters, which can be applied to any CPVA. With this formulation, the dynamic behaviour of a simple 2DOF torsional system with a CPVA, spinning at constant speed, is verified.
It is important to mention that this work is the first part of a two part work. In the second part, this formulation is applied to a more complex system with a CPVA, and results are shown to be coherent with the analyses shown here.
Comparative Analysis of Features of Task Based Conceptual Design Methods
Authors: Darbinyan H. V. 
Published: April 2014

In well known conceptual design methods movement based working principles are considered to provide demanded key function of the future mechanism. Acceptable kinematical structures are searched within large number of topological diagrams generated on the base of original mechanism selected in accordance with functional demand. Further filtering of topological diagrams is leaving structures which are satisfactory for structural characteristics and additional functions.
For many cases of mechanical design those concept design methods are not providing equal synthesis conditions for all functions, discriminating the rest of functions against the key function.
The suggested novel concept design method [1] provides possibility of wide modifications of mechanism and function entities with mandatory dependence between sets of functions and mechanism’ various embodiments and implies application of identical design cycles for different stages of concept design. Some chapters of this method, as main idea, unified synthesis tools, modeling in concept design, graph and matrix based formalization of functions and mechanisms were presented in the earlier publications [2, 3]. Current study aims to formalize the concept design method itself, which facilitates presentation of the suggested design method and enables its formalized comparison with existing ones. Examples of product concept design are considered and resolved by existing methods and by the novel one, thus making obvious feature and performance efficiency evaluation.
Vibration Control for Parallel Manipulator Based on the Feed Forward Control Strategy
Authors: Li Ming , Wu Huapeng , Handroos Heikki , Ceccarelli Marco , Carbone Giuseppe 
Published: April 2014

Due to the high stiffness, high dynamic performance, the parallel manipulator presents great advantages in the industrial manufacture. However in the machining process, the external low frequency disturbance, e.g. the varying cutting force, has a significant effect on the control system of parallel manipulator, which presents a chatter phenomenon on the end-effector of manipulator.
In this paper, a feed forward control strategy is proposed to eliminate the effect of the random external disturbance on the control system of parallel manipulator. By applying the external disturbance force on the inverse dynamic model, the compensation torque is calculated and fed forward into the manipulator driving joints to cancel out the effect of the disturbance acting on the manipulator end-effector. The key issue herein is to be able to establish the accurate dynamic model for the parallel manipulator.
Furthermore, in order to guarantee the position precision of the manipulator, a feed forward model-based control strategy combined with the feedback loop PV (position and velocity) control has been developed based on the reference trajectory, which could relatively simplify the highly nonlinear control system of the parallel manipulator and obtain a stable tracking error model.
The whole research has been carried out on a parallel manipulator named CaPaMan which has been built in the laboratory of robotics and mechatronics in university of Cassino and South Latium. The results show that the chatter phenomenon could be utterly depressed by the force compensation from the feed forward path of the external disturbance; meanwhile the model-based controller can guarantee the trajectory tracking accuracy within a stable error by choosing the suitable PV gains.