bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential of the Variable Valve Actuation (VVA) Strategy on a Heavy Duty CNG Engine
Authors: Baratta Mirko , Finesso Roberto , Misul Daniela , Spessa Ezio , Tong Yifei , Peletto Cesare
Published: October 2014

The environmental concerns officially aroused in 1970s made the control of the engine emissions a major issue for the automotive industry. The corresponding reduction in fuel consumption has become a challenge so as to meet the current and future emission legislations.

Given the increasing interest retained by the optimal use of a Variable Valve Actuation (VVA) technology, the present paper investigates into the potentials of combining the VVA solution to CNG fuelling. Experiments and simulations were carried out on a heavy duty 6-cylinders CNG engine equipped with a turbocharger displaying a twin-entry waste-gate-controlled turbine. The analysis aimed at exploring the potentials of the Early Intake Valve Closure (EIVC) mode and to identify advanced solutions for the combustion management as well as for the turbo-matching. The engine model was developed within the GT-Power environment and was finely tuned to reproduce the experimental readings under steady state operations. The 0D-1D model was hence run to reproduce the engine operating conditions at different speeds and loads and to highlight the effect of the VVA on the engine performance as well as on the fuel consumption and engine emissions. Pumping losses proved to reduce to a great extent, thus decreasing the brake specific fuel consumption (BSFC) with respect to the throttled engine. The exhaust temperature at the turbine inlet was kept to an almost constant value and minor variations were allowed. This was meant to avoid an excessive worsening in the TWC working conditions, as well as deterioration in the turbocharger performance during load transients. The numerical results also proved that full load torque increases can be achieved by reducing the spark advance so that a higher enthalpy is delivered to the turbocharger. Similar torque levels were also obtained by means of Early Intake Valve Closing strategy. For the latter case, negligible penalties in the fuel consumption were detected. Moreover, for a given combustion phasing, the IVC angle directly controls the mass-flow rate and thus the torque. On the other hand, a slight dependence on the combustion phasing can be detected at part load. Finally, the simulations assessed for almost constant fuel consumption for a wide range of IVC and SA values.

Specific attention was also paid to the turbocharger group functioning and to its correct matching to the engine working point. The simulations showed that the working point on the compressor map can be optimized by properly setting the spark advance (SA) as referred to the adopted intake-valve closing angle. It is anyhow worth observing that the engine high loads set a constraint deriving from the need to meet the limits on the peak firing pressure (PFP), thus limiting the possibility to optimize the working point once the turbo-matching is defined.
A Novel Design of a Self-Sensing Compensating Restrictor/Pad Module for Hydrostatic Bearings
Authors: Yang Cho-Yun , Yang Cho-Yu , Lu Jia-Wei , Lee Wei-Chih , Hung Yu-Min , Sung Cheng Kuo
Published: October 2014

This paper proposes the design of a self-sensing compensating restrictor/pad module for hydrostatic bearings. The module consists of a bearing pad and the associated restrictor featuring the characteristics of self-sensing compensation and easy installation. The paper first introduces the configuration of the proposed module. Then, the lumped parameter model was used to derive the equation for the relationship between the pocket pressure and the bearing gap. Furthermore, equations governing the stiffness and load-carrying capacity of the bearing were also obtained. Influences of the design parameters, such as the land length and pressure ratio, on bearing performance and the feasibility of the new design were studied both analytically and experimentally. Results of the theoretical analysis were compared with that of the experiment. Superior performances on the aspects of stiffness and load-carrying capacity, as well as time delay due to the distance between restrictor and bearing pad to the traditional restrictors such as capillary and orifice were achieved. In addition, the proposed restrictor possesses the advantages of simplicity for both manufacturing and assembly in comparison with the membrane-type restrictors.
An Inner-Enterprise Design Knowledge Flow Management Approach
Authors: Zhang Zhinan , Long Qing , Liu Yonghong , Xie Youbai
Published: October 2014

Design knowledge is distributed unevenly across organizational boundaries within large enterprises. Within this context, there are two main barriers to quick and reliable knowledge flow. The first is the organizational boundaries which will influence the efficiency of new design knowledge flow from when and where it is located to when and where it is need for application. The second is that one organization or sub-company of the same large enterprise often knows little about what kind of design knowledge or capability another one has. These barriers will prevent the flow of knowledge. Therefore, there is a need to develop methods and tools to improve the performance of knowledge flow within large enterprises. This paper first presents a brief introduction to the context and background information of our knowledge flow management practice in a large enterprise. Then the definition of key elements of design knowledge flow are introduced and analyzed. After that, we propose a service-based framework for the management of design knowledge flow; this framework focuses on organizing knowledge providers and developing a knowledge service platform. The proposed approach was primarily validated and verified in a large construction machinery enterprise. In addition, future work on improving the approach to knowledge flow management is also briefly discussed.
Effect of Microstructure on Mechanical Properties and Abrasive Wear Behavior of Low Carbon Dual-Phase Steels
Authors: Tüzemen Mehmet Çağrı , Salamci Elmas
Published: October 2014

The mechanical properties and wear behavior of Dual Phase (DP) steels have been investigated and compared with those observed in normalized (N) steel that has the same chemical composition. The DP steels having different content and morphology of martensite were produced by varying intercritical annealing temperature and initial microstructures. Mechanical properties of four different DP steels and N steel have been investigated by carrying out tensile and macrohardness tests. Dry sliding wear tests have been conducted on four different the DP steels and the N steel using pin-on-plate to investigate their wear characteristics. It has been found that the yield and tensile strengths and macrohardness increase with increasing martensite content and decreasing martensite size. The yield and tensile strengths and macrohardness of the N steel were significantly lower than the DP steels whereas percentage of total elongation was higher. Wear properties are improved by increasing martensite volume fraction and size in the DP steels. The N steel specimen showed the highest wear rate.
Problem-Based Learning Approach in Marine Engineering Education Using Mobile Devices and Internet Tools
Authors: Mora Luis Carlos E. , Marrero Antonio González , Mellado Reyes Carrau , Añorbe-Diaz Beatriz , Martín-Gutierrez Jorge
Published: October 2014

The skills of Marine Engineering graduates should be strongly oriented to problem solving for situations without external direct assistance. Marine professionals should also be able to take the right decisions under difficult situations like emergencies.

Work-group and job planning is an every day requirement, especially when doing maintenance and reparation tasks. Besides, marine technology has advanced quickly and knowledge recycling is a must on every shipping company, but operation and maintenance procedures have usually to be learnt on the go. During last decades, marine engineering students had not got immersed into a real challenge work environment until going onboard for the first time when finishing their studies. The adoption of a problem-based learning is intended to solve this situation, so students will have a closer contact with real decision-taking and auto-learning situations on earlier stages. We pretend to create more engaging experiences and introduce our students into real collaborative environments using technologies; especially those based on mobile devices and Internet tools.

Grounded in motivation theory, this research evaluates how the context of problem-based learning (PBL) affects aspects of motivation in students of marine engineering. Our research aims to answer: 1) How does the context of service in project-based learning affect student motivation? 2) What factors are most influential on student motivation to persist in project-based learning experiences?

The results show different behavior in freshmen and senior students.
Risk-Based Stability Assessment of a Gantry Crane
Authors: Xu Bin , Yu Zhongjian , Yang Yuqing , Tang Xiaoying , Zhang Tao
Published: October 2014

Stability of a gantry crane was a challenge in its structure design. A new risk-based stability assessment approach was proposed in this paper. Analytical method was introduced firstly, and then finite element method was adopted to evaluate the stability of square bar. In order to verify the finite element models, results of buckling analysis were compared with the results of analytical method. Secondly, this finite element analysis was applied in stability assessment of a gantry crane, and through parameterized analysis risk elements were identified. Finally, risk-based stability assessment was applied to this gantry crane, and neural network algorithm was adopted to evaluate the risk elements which were defined by finite element analysis. The evaluating results were well consistetent with statistical data, which indicated this risk-based stability assessment approach was reliable which showed a potential in engineering application.
Using Data Mining Approaches for Force Prediction of a Dynamically Loaded Flexible Structure
Authors: Schlechtingen Meik , Achiche Sofiane , Costa Tiago Lourenco , Raison Maxime , Santos Ilmar
Published: October 2014

This paper presents the results obtained from a research work investigating the performance of different Adaptive models developed to predict excitation forces on a dynamically loaded flexible structure. For this purpose, a flexible structure is equipped with acceleration transducers at each degree of freedom and a force transducer for validation and training. The models are trained using data obtained from applying a random excitation force on the flexible structure. The performance of the developed models is evaluated by analyzing the prediction capabilities based on a normalized prediction error. The frequency domain is considered to analyze the similarity of the frequencies in the predicted and the original force signal. For a selection of the best models, a more advanced performance analysis is carried out. This includes application of the trained models to deterministic and non-deterministic excitation forces with different excitation frequencies and amplitudes. Additionally, the influence of the sampling frequency and sensor location on the model performance is investigated. The results obtained in this paper show that most data mining approaches can be used, when a certain degree of inaccuracy is accepted. Furthermore, the comparison study points out that the transducer location is crucial for the model performance. However, there exists no general solution for the final selection of models.
Multiobjective Pareto-Based Optimization of pMUT Hydrophone With Piezoelectric Active Diaphragm
Authors: Shevtsov Sergey , Chang Shun-Hsyung (Stephen) , Kalinchuk Valery , Zhilyaev Igor , Shevtsova Maria
Published: October 2014

The design of high-sensitive hydrophones is one of the research interests in underwater acoustics. Due to progress of micro- and nanotechnology the most attention of researchers is attracted by the transducers that use the micro-electromechanical system (MEMS) concept. Piezoelectric micro-machined ultrasonic transducers (pMUTs) present a new approach to sound detection and generation that can overcome the shortcomings of conventional transducers. For accurate ultrasound field measurement, small size hydrophones which are smaller than the acoustic wavelength are required for providing an omnidirectional response and avoid spatial averaging.

This paper presents some results of multiobjective optimization for membrane-type piezoceramic MEMS based transducers. We investigate the miniaturized membrane-type sensor with perforated holes in the active PZT and intermediate membranes, with the protective plates and a vacuum chamber. An influence of the protective plate elastic and viscous properties, the dimensions and the relative area of the perforated holes on the sensitivity’s frequency response of the hydrophone was studied for the broadening and equalizes the operating frequency band. We optimize these key parameters using the Pareto approach with the finite element (FE) model of coupled piezoelectric-acoustic problem. Finally, the set of optimized hydrophone structures and some examples of obtained sensitivity frequency response are demonstrated.
Measurement and Analysis on Energy Efficiency of Elevators in Shanghai
Authors: Hao Wu , Xiaoqing Chang , Jiai Xue
Published: October 2014

Shanghai is the largest city of elevators in the world with 165000 elevators and escalators. According to latest research, elevators typically account for about 3% to 8% of the overall electricity consumption of a building. Therefore, it is significantly to study the energy efficiency of elevators in Shanghai. However, elevators have received little attention from an efficiency perspective in the past. To recover this gap, this paper analyses classification method on energy efficiency of elevators in Shanghai and suggests policy measures for energy conservation. First, Representative elevators in Shanghai were collected as research objects; second, a new energy efficiency classification method was established on the modification of VDI4707 according to actual situations in China, then, energy consumption of these elevators were measured and classified according to the new method. Finally, the influence factors of elevator energy efficiency were studied, and suggestion on the improvement of the energy efficiency of elevators in Shanghai was given.
New Schoenflies-Motion Manipulator Implementing Isosceles Triangle and Delassus Parallelogram
Authors: Lee Chung-Ching , Hervé Jacques M.
Published: October 2014

Schoenflies (X) motion is a 4D displacement Lie group including a spatial translation and any rotation whose axis is parallel to a given direction. Delassus parallelogram has four parallel screw (H) pairs with related pitches and the isosceles triangle is a special HHHP. After merging these two chains, an HHH-//-HHH generator of 2-DoF translation along a right helicoid is derived. It produces a 2-DoF motion mathematically modeled by a 2D submanifold of a 4D group of X-motion. Because of the product closure in an X-group, the 4-DoF generator with HHH-//-HHH loop serving as a subchain is revealed by adding two H pairs with axes parallel to fixed H axes. Parallel arrangement of two generators of the same X motion results in a new Schoenflies-motion manipulator with hybrid topology for 4-DoF pick-and-place operations. Four fixed H pairs (two double Hs) can actuate this manipulator and the two coaxial Hs must have distinct pitches. In addition, the possible design choices of special architectures are introduced for practical applications. Computer simulations of the new parallel manipulator with Schoenflies motion verify the effectiveness.
Finite Element Method Modelling and Analysis on Compressor Coupling Integrity Review
Authors: Hamdi Edi , Dirgantara Tatacipta , Setiawan Hery
Published: October 2014

Finite element method modeling for flexible coupling of gas turbine compressor package installed in one of PT. Pertamina Hulu Energi Offshore North West Java (PHE ONWJ) facility has been completed. The model delivered result which is in acceptable level of accuracy as compared to manufacturer operating guideline as well as follows in general to guidance of API 671 widely used as industrial code and standard for coupling.

The scope of modeling is including the static and dynamic analysis for both perfectly aligned (used as base reference) and for misaligned condition. The scope covers as well the cyclic stresses which in turns determining the disc pack life time. The major challenge on the modeling is mainly to vary the degree of misalignment and how to distribute the additional load to the flexible part of the coupling causing deformation of disc pack.

The static analysis modeling reveals that the stresses are still below the yield point when aligned perfectly even in high vibration situation, but when it reaches up to 0.1 degree of misalignment with maximum torque the Von-Misses stress has exceeded the yield. The dynamic analysis shows that for similar 0.1 degree the fatigue factor of safety also has exceeded API 671 requirement.

Following the actual coupling failure events, the model has successfully indicated the location of highest stress correlated to crack initiation as compared to actual cracks found in existing discs specimen. The model has been validated as well with the result of material analysis of the damaged flexible discs showing that the failure occurred due to over misalignment.

In addition to manufacturer manual description, the model is capable to recommend maximum angular misalignment that need to be monitored during compressor operation and provide basis to calculate safety factor to comply API 671 guideline.

As oil and gas exploration and production company which focus on possible highest energy efficiency of its operating platforms — which all is located offshore, the work leads a way in integrity management of turbo-machinery equipment in order to maximize running time and minimize production shutdown.
A New Multi-Objective Evolutionary Algorithm for Optimizing the Aerodynamic Design of HAWT Rotor
Authors: Alfayyadh Ekhlas M. , Bakhy Sadeq H. , Shkara Yasir M.
Published: October 2014

This paper presents a new multi-objective evolutionary algorithm (MOEA) for optimum aerodynamic design of horizontal-axis wind turbines (HAWT). The design problem is set to find the blade shape such that optimizing multi-objective at different airfoil profiles. Combined Blade Element Momentum (BEM) theory and two different algorithms (Genetic (GA) and Enumeration) are used. Flow around subsonic airfoils is analyzed using XFOIL software. WINDMEL III wind turbine is selected to improve its aerodynamic performance with different airfoil profiles technique of National Renewable Energy Laboratory (NREL) family. Employing Genetic Algorithm embodied in Blade Element Momentum theory to calculate power, thrust and starting torque coefficients that are the fitness function. Another method, Enumeration method, is used to enhance evolutionary method results. The optimum solution acquired from combination of Genetic Algorithm and Blade Element Momentum theory of three blades configuration increased power coefficient by (25.8 %) and thrust coefficient by (16.6%). Enumeration method results increased power coefficient by (13.8%), while thrust coefficient decreased by (0.2%) from the original design. In general, the evolutionary method of combined GA and BEM theory with different airfoil profiles technique improved the turbine aerodynamic performance, and the results are in good agreement with other published papers.
Effect of Temperature Gradient on the Mechanical Buckling Resistance of FGM Shallow Arches
Authors: Bateni M. , Eslami M. R.
Published: October 2014

This work presents a closed form investigation on the effect of temperature gradient on the buckling resistance of functionally graded material (FGM) shallow arches. The constituents are assumed to vary smoothly through the thickness of the arch according to the power law distribution and they are assumed to be temperature dependent. The arches subjected to the both uniform distributed radial load and central concentrated load and both boundary supports are supposed to be pinned. The temperature field is approximated by one-dimensional linear gradient through the thickness of the arch and the displacement field approximated by classical arches model. Also, Donnell type kinematics is utilized to extract the suitable strain-displacement relations for shallow arches. Adjacent equilibrium criterion is used to buckling analysis, and, critical bifurcation load is obtain in the complete presence of pre-buckling deformations. Results discloses the usefulness of using the FGM shallow arches in thermal environment because the temperature gradient enhances the buckling resistance of these structures when they are subjected to a lateral mechanical load.
On the Stress Triaxiality Sensitivity of High Density Polyethylene
Authors: Hachour Kamel , Sadeg Lydia , Sersab Djamel , Aberkane Meziane
Published: October 2014

The aim of this paper is to investigate the stress triaxiality effect on the yield stress for the high density polyethylene (hdpe). An experimental protocol has been established to get a wide range of stress triaxialities (negative and positive). Tensile tests, uniaxial compression and simple shear were performed on specimens with different geometries: notched round bar specimens with different curvature radii, cylindrical specimens and parallelepiped specimens respectively. Biaxial tests (combinations of tensile/compressive and shear loading) are also achieved on butterfly-shaped specimens using an Arcan apparatus in order to expand the stress triaxialities. The experimental results demonstrate that the yield stress depends on the stress triaxiality which is due to the hydrostatic stress influence.
Numerical Investigation on Thermal Behaviors of an Inclined Ventilated Roof
Authors: Manca Oronzio , Mangiacapra Antonio , Marino Salvatore , Nardini Sergio
Published: October 2014

This paper illustrates a numerical investigation on a prototypal ventilated roof for residential use. The analysis is carried out on a two-dimensional model in air flow and the governing equations are given in terms of k-ε turbulence model. Due the symmetry geometric and thermal has been studied a single flap of the roof. The analysis is performed in order to evaluate the thermofluidodynamic behavior of the roof as a function of geometric parameters such as the inclination, the layer of ventilation gap and the hipped roof height. The problem is solved by means of the commercial code Ansys-Fluent and the results are performed for assigned wall heat flux on the top wall. Results are given in terms of wall temperature distributions, air velocity, temperature profiles along the cross sections of the roof to estimate the differences among the various configurations. Further, the ventilated roof is compared with other types of roof.
Rheological Characterization of Energetic Materials by Rotational Testing Techniques
Authors: Martinez-Pastor Juan , Franco Patricio , Ramirez-Fernandez F. Javier
Published: October 2014

In production of energetic materials, the rheological behavior of propellant doughs is a key factor to identify optimum and safe conditions for processing these special compounds. The analysis of their rheological properties during mixing and extrusion stages is needed to clarify the complex interrelations between the different process parameters and the expected performance of these products, providing essential information for the possible increase of system productivity and overall product quality. In this study, the rheological analysis of triple-base propellants and a propellant simulant was carried out by a DHR-2 rotational rheometer of TA Instruments. Furthermore, different testing techniques were evaluated for appropriate characterization of these propellants. According to the results of rheological measurements, these triple-base propellants were found to correspond to shear-thinning materials (pseudo-plastic behavior). Finally, the results obtained from these experimental observations were matched to well-known constitutive empirical models to describe the mathematical relation between viscosity and shear strain rate.
Large Amplitude Thremally Induced Vibration of Circular FGM Plate
Authors: Kiani Yasser , Eslami Mohammad Reza
Published: October 2014

Vibration of a solid circular plate subjected to rapid surface heating is analyzed in this research. Properties of the plate are all temperature and position dependent. Plate is modeled using the first order shear deformation theory. To account for the large deformations, the von Kármán type of geometrical non-linearity is taken into account. Plate is subjected to surface heating at both top and bottom surfaces. Time dependent one-dimensional heat conduction equation is solved via an iterative finite difference scheme and thermal force and thermal moment resultants are evaluated at each time step. Non-linear motion equations of the plate are established with the aid of Hamilton’s principle and the generalized Ritz method. Solution of such equations is obtained employing a hybrid Newton-Raphson-Newmark method. It is shown that thermally induced vibrations exist for the sufficiently thin FGM plate.
Motion Simulation of a Hybrid Parallel Robot for Ankle Rehabilitation
Authors: Rakhodaei Hamid , Saadat Mozafar , Rastegarpanah Alireza
Published: October 2014

This paper addresses the path planning of a hybrid parallel robot for ankle rehabilitation. The robot contains 3-DOF parallel mechanism that is attached on top of the 6-DOF hexapod. The 6-UPU-3-UPR parallel robot is developed to simulate ankle motions for the rehabilitation of post-stroke patients with an affected ankle. The inverse kinematic of hybrid parallel robot is developed in order to track the end-effector’s position through Matlab software. The calculated stroke size of each actuator is imported to apply the forward kinematic for determining the position of end-effector. The experimental and simulation values of the hexapod are compared with those of the hybrid structure through a number of exercise motion paths. The results reveal that, in general, the simulation values follow well the experimental values, although with different degrees of variation for each of the structures considered.
Applying Novel Future-Internet-Based Supply Chain Control Towers to the Transport and Logistics Domain
Authors: Alias Cyril , Jawale Mandar , Goudz Alexander , Noche Bernd
Published: October 2014

Competing supply chain networks all around the globe are under scrutiny due to ever-growing demand for service improvement and cost reduction. A major field of action in this respect is the realization of real-time monitoring means for supply chain processes including a constant comparison of the respective progress status with the planning guidelines and the best possible management of deviations and exceptions.

Control towers have been named as the future tool of supply chain monitoring for quite a while. They are defined as decision-support systems merging different data streams from various subordinate levels and displaying the consolidated information at a higher level for the purpose of monitoring and control of processes while pursuing the goal of optimal process operation. Contrary to the technological constraints of the past which prevented a continuous and fully transparent real-time monitoring of supply chain processes, innovative evolving so-called Future Internet technologies enable genuine transparency and the handling of exceptions in a timely and cost-efficient manner nowadays. With the help of such technologies, newly designed and built control towers are supposed to assist actors on the planning and execution levels of their respective supply chain networks in their decision-making in case of relevant deviations or exceptions. This again raises the market acceptance of such control towers.

This paper presents a novel approach to the functional principle of Future-Internet-based control tower solutions and describes the different components therein. Especially, the incorporation of manifold information sources from the Future Internet technologies for the purpose of real-time monitoring and control of supply chain processes is highlighted in the paper.
Study on an Optimized Configuration of Conformal Cooling Channel by Branching Law
Authors: Choi Jae Hyuk , Kim Jin Su , Han Eun Su , Park Hyung Pil , Rhee Byung Ohk
Published: October 2014

Since the 3D printing technology was applied to metallic materials, the conformal cooling channel has been widely utilized for injection mold with a higher cooling efficiency. The conformal cooling channel provides higher degree of freedom in shape and size. It is more effective to apply it to convex core accumulating more heat than the concave side. However, there has not been a standard design method for the conformal cooling channel. Depending upon channel design, the cooling efficiency would not be improved. Sometimes dead flow zones could be made in the channel. Currently every engineer makes the cooling channel design of his own. In this work, we proposed an automated optimum design method for the conformal cooling channel. In the proposed design method, whole product surface is divided into smaller domains with equal thermal energy by Voronoi diagram algorithm. Then cooling channels are installed along the centers of the domains by a binary branching algorithm. The objective of the optimization was the minimization of the product surface temperature deviation. The cooling channels are branching out over the product surface through the evolutionary steps until the objective was satisfied. The injection molding CAE analysis was done by Moldflow, and the optimization by PIAnO. The sample product was an eye-glass lens product.
Application of Structural Integrity Concepts to NPP Piping and Equipment During Design, Commissioning and Operation
Authors: Arzhaev Alexey , Sivakov Sergey , Arzhaev Kirill , Butorin Sergey , Makhanev Valentin
Published: October 2014

Application of Structural Integrity Concepts to RF NPP piping and equipment have started in Russia in the beginning of 1990s from requirements to Leak Before Break (LBB) calculation studies adopted by regulatory body. Results of first practical LBB Concept application to RF NPP piping have been reported at Lyon LBB Conference in year 1995.

Experience of LBB Concept practical application in Russia during 1990s formed strong basis for issuing comprehensive guideline RD 95 10547-99 which stated LBB Concept basic principles and requirements applicable to RF NPPs with Light Water Reactors (LWR) at all stages of Life Cycle: design, commissioning and operation. Requirements of RD 95 10547-99 guideline have been in good correspondence to classic LBB principles used in many European countries, USA, Japan and to IAEA Technical Documents as well.

RF NPP piping operation experience analysis have revealed necessity of producing more general methodology — Break Preclusion (BP) Concept — to substantiate structural integrity of piping potentially susceptible to active degradation mechanisms like Flow Accelerated Corrosion (FAC), Intergranular Stress Corrosion Cracking (IGSCC), etc. BP and LBB Concepts are based on the same major principles: (a) quality of design, manufacturing, assembling, (b) monitoring of degradation and operating conditions, (c) enveloping loading conditions with respect to maximum design loads, (d) calculation and experimental substantiation of failure according to LBB scenario. LBB Concept requires full implementation of principles (a)÷(d) and BP Concept allows to achieve balance in implementation of principles (a) and (b) while principles (c) and (d) should be fully implemented.

Memorandum of 8th International Scientific and Technical Conference “Safety of VVER NPPs” in year 2013 stated as a 1st priority goal to substantiate structural integrity of main components for Long-Term Operation (LTO) during 60–80 years. Actual regulatory demands to operating NPPs also produce strong demand to provide structural integrity arguments for safety important piping and equipment as a part of periodic safety justification of NPP Unit needed for license extension.

Peculiarities of structural integrity concepts application to safety important piping and equipment at different stages of NPP Unit Life Cycle (design. commissioning and operation) are discussed in paper with emphasis on technical measures providing conditions for effective degradation monitoring and prevention during LTO. Perspectives of regulatory documents improvement are also discussed.
Performance Evaluation and Environmental Analysis of an Electrically Assisted Bicycle Under Real Driving Conditions
Authors: Iodice Paolo , Abagnale Carmelina , Cardone Massimo , Strano Salvatore , Terzo Mario , Vorraro Giovanni
Published: October 2014

This paper describes the on-road test program that was used for a performance study and environmental analysis of an electrically assisted bicycle in the urban area of Naples. For this purpose, the vehicle was tested on different test tracks, cycling over 2000 km, and then making a general assessment about the driving behavior under real conditions.

Based on the findings obtained during the different test samples, an appraisal of the electric traction offered by this bicycle on the driving comfort was evaluated for different conditions: electrical assistance at start, on a flat road and when riding uphill. The power requirements in different typical riding situations were also calculated: these results were estimated by experimental kinematic parameters that describe the driving dynamics collected during the real-life applications. An environmental analysis was made and also put against the environmental impact of a thermal moped.
Influence of Opposing Jet on an Aerodisk Nose Cone at Hypersonic Flow
Authors: Gerdroodbary M. Barzegar , Goudarzi A. M. , Imani Misagh , Sedighi K. , Ganji D. D.
Published: October 2014

When flying at hypersonic speeds, it is a fundamental requirement to reduce the high drag resulting from a blunt nose cone in the ascent stage to increase the payload weight on the one hand and decrease the amount of energy needed to overcome the Earth’s gravity on the other. However, an aerospike can be attached on the front of the nose cone to obtain a high drag and heat load reduction. This study describes novel technique of an active flow control concepton nose cone with aerodisk that uses counterflowing jets to significantly modify external flowfields. In fact, this method strongly disperse the shock waves of supersonic and hypersonic vehicles to reduce aerothermal loads.Numerical simulations of a 2D axisymmetric aerodisked nose cone in hypersonic flow are conducted, and innovative techniques involving forward injection of gas from the stagnation point of the sphere are investigated; techniques include injection of various counterflowing jets (Helium and Carbon dioxide) as a coolant jet from the nose cone behind the aerodisk. In this study, the characteristics of the various jet conditions of a counterflowing jet on a cone surface were investigated numerically to improve performance of the jet on heat reduction at surface of a nose. Different Mach numbers at different altitudes have been chosen to investigate the effect of the aerospike on the nose cone’s surrounding flowfield. The drag and the heat load reduction is numerically evaluated at Mach numbers of 5.75. The results show that the lighter gas, Helium, is found to have a better cooling performance than Carbon Dioxide in low pressure ratios. The film cooling of Helium jet due to its lower specific heat capacity (Cp) character is efficient on heat load of the nose cone.
Modeling and Simulation of Technological Assembly Process With Utilization of MTBF Parameter
Authors: Ciszak Olaf
Published: October 2014

The present study deals with vital aspects of technological assembly process modeling and simulation based on application of the MTBF (Mean Time Between Failures) parameter, as exemplified upon experimental assembly of an automobile disc brake caliper unit. The proposed simulation model of the analyzed assembly work cell is hereby expounded upon. The paper further presents the outcomes and conclusions of the undertaken experimental procedure.
Multi-Disciplinary and Multi-Objective Optimization of a Hydro-Pneumatic Balancing Cylinder for an Industrial Robot
Authors: Persson Johan A. , Feng Xiaolong , Wappling Daniel , Ölvander Johan
Published: October 2014

This article presents an optimization framework that is used to optimize a hydro-pneumatic balancing cylinder for industrial robots. A balancing cylinder is a device that is used to balance the gravitational torque of one of the main axes of a high-loaded serial industrial robot. The design of components for an industrial robot is multi-disciplinary, since disciplines such as multi-body dynamics, drive train design and robot control are needed. The design process is also multi-objective since the functionality of the balancing cylinder should be optimal, while its size and cost should be minimal. The article therefore also contains a discussion about multi-disciplinary and multi-objective optimization of complex products.
A Novel Brushless Permanent Magnet Motor for Electric Scooters
Authors: Liu T. S. , Chung Y. C.
Published: October 2014

The purpose of this study is to design brushless permanent magnet DC motors for electric vehicles based on a pole-changing method. By generating a pulse when changing the number of poles, magnetization of magnets can be changed appropriately and the principle of pole-changing motors can be applied to permanent magnet machines. This kind of machine not only retains the feature of permanent magnet machines in efficiency, but also acquires wide speed range. In this study, a pole-changing method using common windings is proposed and performance of brushless permanent magnet DC pole-changing motors is investigated. According to T-N curves, the proposed brushless permanent magnet pole-changing motor yields larger starting torque and wider speed range than motors with a fixed number of poles.
A Numerical Model to Investigate Evaporative Condensers Behaviour at Tube Scale
Authors: Fiorentino Maria , Starace Giuseppe
Published: October 2014

Evaporative condensers operate at lower temperatures and with a higher efficiency compared to air condensers, as heat rejection is limited by air wet bulb temperature and mainly caused by water vaporization. This reduces the compressor pressure-lift and improves refrigeration cycle performance.

Due to complex phenomena of heat and mass transfer on the tube bundles, modeling the evaporative condensers is a hard task and fine grids in numerical simulations are requested to reach acceptable results.

A two-dimensional steady state numerical model at the single tube scale has been developed in Ansys-Fluent (release- 14.5), adopting the VOF multiphase model.

Moist air has been treated as a mixture of air and water vapor species, while water vaporization and latent heat have been modeled with a C++ User Defined Function.

The tube wall temperature has been assumed constant.

The aim of this work is to describe the developed numerical model and to validate it by comparing results obtained at different operating conditions with empirical relationships found in the literature in terms of combined and overall heat transfer coefficients.

Combined heat transfer coefficient variation along the tube surface has been analyzed, observing that the heat transfer coefficient is higher in the impingement zone, becomes approximately uniform and rises approaching the trailing edge.

Moisture content distributions at different sections through the heat exchanger have been examined in detail as well.

This study will be the basis to investigate the performance of the whole condenser taking into account the real evolution of the operating conditions of each single tube in the bundle, whatever its arrangement.
A Simulation Study of Flexible Manufacturing System Using Dynamic Scheduling Approach
Authors: Mahalingam Vijay Kumar
Published: October 2014

This paper presents a simulation study aimed at evaluating the performances of a typical Flexible manufacturing system (FMS) problems in terms of make span, average flow time, average delay time at local buffers and average machine utilization, subject to different control strategies which include routing flexibilities and dispatching rules. The routing strategies under evaluation are ‘No Alternative Routings (NAR)’; ‘Alternative Routings Dynamic (ARD)’; and ‘Alternative Routings Planned (ARP)’. The ARP rule was introduced into the FMS and coded with C++ program. The above routing strategies are combined with five dispatching rules and studied in different production volumes. Since an FMS usually deals with a variety of products, effects of changing the part mix ratio are also discussed. Simulation study was performed by using ARENA software. Finally results indicate that the ‘alternative routings planned’ strategy outperforms other routing strategies in general.
Electro-Mechanical Control Loading System for Rotary Wing Aircraft Simulators
Authors: Aygün Mehmet Murat , Tascıoğlu Yiğit , Genç Gürsoy , Altunay Mustafa
Published: October 2014

The focus of this paper is on the development of a high-fidelity electro-mechanical Control Loading System (CLS) for a rotary wing aircraft simulator. CLS is one of the major components of a flight simulator. It is used for providing realistic force feedback to pilots. The pilot in a real aircraft feels the forces acting on control surfaces through cockpit controls. During simulation, these forces are produced by CLS actuators. For this reason, CLS must behave exactly like the aircraft control hardware, statically and dynamically. The fidelity of the force feel simulation is a key criterion for flight simulation certification. It is also important that a CLS design is reconfigurable and modular such that it conforms easily to different simulator models and simulations of different aircrafts. The work also includes system integration of a research simulator for testing purposes. Design and selection of hardware and software components of the CLS and the simulator are presented along with the overall system architecture.
Thermal Properties of Polymer-Metal Composites
Authors: Szostak Marek , Andrzejewski Jacek
Published: October 2014

The objectives in this paper are to investigate the effects of the filler content and size on the effective thermal conductivity of the PE/Al; PE/Cu, PE/Fe and PE/bronze composites. The polymer matrix of the polymer/metal composites was two types of polyethylenes: LDPE and HDPE (from Basell Orlen). The following polymer/metal composites obtained by extrusion process containing: 10% by weight of Al, Cu, Fe and bronze powder in LDPE matrix and composites containing 5, 10, 15 and 20% by weight of Al flakes in HDPE polymer were prepared and tested. Adding in the extrusion process 10% by weight of bronze powder into the polyethylene, increased more than five times the thermal diffusivity of produced composite. Use as a filler 20% wt. of aluminum flake increases it by more than twice. The study showed the ability to produce polyethylene matrix composites with the addition of metal powder fillers (Al, Cu, Fe, and bronze). Analyzing the measuring results of thermal diffusivity coefficient by Angstrom method, it can be concluded that with the appropriate filler content, the particles are located close enough to each other to form a continuous conductive path, then the thermal diffusivity of the composite increases significantly.
Experimental Transfer Path Analysis for a Heavy Duty Truck
Authors: Stan Andrei Cristian , Yenerer Hakan , Sendur Polat , Basdogan Ipek
Published: October 2014

Most of the mechanical systems are composed of different subsystems coupled by several links. Any excitation acting on the system is divided into several internal forces which propagate through these links or so called transfer paths. This paper presents the use of experimental transfer path analysis in identifying the transmission paths for a heavy duty truck in order to estimate the vibration and noise transmitted from the cabin and engine mounts. The most challenging part of the TPA analysis is estimation of the internal operational forces so that the total response can be predicted accurately. At the circumstances where direct measurement of the operational forces is impossible, especially for complex structures, a common approach to address the problem is based on a measured frequency response function (FRF) matrix and a set of operational responses. The main problem of this approach is the inversion of the FRF matrices which can be ill-conditioned. Once the internal operational forces are estimated, the vibration or noise response for the selected location in the truck can be calculated. To validate the predicted results, coherence of the collected data and the condition numbers of FRF matrices are investigated so that the accuracy of the predicted results can be quantified for the frequency band of interest. The predictions of the total response are compared with the experimentally measured data such that the coherence and condition number related observations are validated.
Cutting Tools Offset in Lathe Machines Using a Modern Heuristic Technique
Authors: Al-Ani Dhafar , Habibi Saeid
Published: October 2014

In this paper, an optimal control strategy (i.e., offset settings system) based on the new Multi-objective Particle Swarm Optimization with Differential Evolution (MOPSO-DE) technique is developed and presented. The MOPSO-DE algorithm is used for calculating the optimal positions (i.e., offset settings) for the cutting tools in lathe machines. This optimal control strategy yields interesting results without a need to go through the complex mathematical modeling of the lathe system. The proposed technique is validated considering a real-world industrial system. This strategy is designed to take an action every 20 pieces, and it takes only 2.5 sec to run the code and optimally calculate the new settings. The control strategy is implemented using two high precision linear stepper motors. By implementing the new optimal control strategy, the estimated number of the defective pieces per day can be reduced by 85%.
Application of Extended Kalman Filtering and Novel Spectral Methods in Stochastic Characterization of Quasi-Periodic Slow-Time Varying Rotating Machinery Processes
Authors: Sherman Peter J.
Published: October 2014

Very often processes associated with rotating machinery entail two general types of random processes: (i) quasi-periodic processes linked directly to the machine rotational frequency (including harmonics and sub-harmonics), and (ii) regular processes such as those associated with random vibration of machinery elements. Variability of the rotational frequency and slow-time variability can both be induced by factors such as time-varying external loading and changing thermodynamics (e.g. the influence of road grade and engine temperature on automobiles using cruise control). In this work we incorporate and extended Kalman filter (EKF) model guided by estimates of the family of AR and MV spectral estimates to arrive at a method of decomposing and tracking these two types of processes, along with related parameters (e.g. frequency jitter bandwidth/intensity and the strength, damping and natural frequency of randomly excited narrowband resonances). This work may be viewed in some ways as an extension of the work presented in [1]. Our findings include (i) for the case of constant nominal speed, the EKF estimates of the time-varying frequency, sine and colored noise processes are quite good; whereas the estimate of the time-varying amplitude is not as good, and (ii) in the case of linearly increasing speed (where the colored noise resonance behavior is only excited in that portion of the observation time where the sine frequency is in close proximity), the estimated root mean-squared errors related to both the frequency and the noise increase linearly with the nominal frequency rate of change.