bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission Pipelines: Are They Still the Safest Way to Transport Energy?
Authors: Kirkwood Mike
Published: October 2014

As the energy landscape changes globally with the development of tight oil and gas resources, questions about the rail safety and tighter regulations around safety and environment, energy insiders are asking the question; are pipelines still the safest way to transport energy? In a recent study conducted by T.D. Williamson (TDW) (1) this paper uncovers some current industry trends, drivers and restraints that will shape the pipelines landscape for the future. The study looked at regional trends, technology applications and future project developments in the pipelines arena and how this is influencing how pipelines are being designed, installed and utilized.

The study identified that there were four distinct pipeline “themes” over the pipeline life cycle, which comprise:

• Infrastructure – pipeline new build for growth, replacement and expansion,

• Integrity Management – management of the integrity for new and existing pipelines,

• Flow Assurance & Throughput – optimizing throughput and uptime for new and existing pipelines,

• Management of Human Capital – acquiring, developing and retaining competent people or outsourcing.

The paper will discuss how these needs imbedded in these themes are met or, as in some cases, unmet.

The paper also looks at developments in materials for new pipelines, pipeline monitoring and leak detection (from cables to dogs to, unmanned vehicles), newer products that are being shipped (from higher hydrogen content methane gas to carbon dioxide from capture schemes to diluted bitumen from the oil sands), the impact of “big data” (from Mb to Yb), and how operators are looking to manage emergencies (from spill response to emergency planning and operational readiness).

This paper will compare safety records for energy transportation as well as the new demands being put on energy companies that will propose an answer to the question posed in the title.
New Approach for the Indirect Detection of Blade-to-Stator Rubbing in Turbo-Machinery Using Wavelet Techniques
Authors: Al-Badour Fadi , Cheded Lahouari , Sunar M.
Published: October 2014

This paper introduces an efficient and powerful approach to fault detection in rotating machinery using time-frequency analysis based on the wavelet transform of the monitored shaft vibration signal. Wavelet techniques are one of the latest powerful tools in analyzing the transient information for condition monitoring and fault detection using vibration signature. The proposed technique combines both the Continuous Wavelet and the Wavelet Packet Transforms. In particular, it exploits the use of the modulus of the local maxima lines in the wavelet domain, to detect impulsive mechanical faults through shaft vibration such as impact blade-to-stator rubbing in turbo machinery.

The proposed new wavelet-based signal processing method was able to detect the singularity in the measured shaft vibration, which was generated by blade rubbing. The singularity detection achieved by the new method was very well supported by its counterpart based on the direct blade vibration measurements.

Our proposed technique was favorably compared with both the time wave and the traditional Fourier Transform techniques. In fact, both the analysis and the extensive simulation work show the superiority of the combined approach (Wavelet Packet Transform and Maxima Lines) over the traditional Fourier-based method, in reliably diagnosing impulsive mechanical faults.
Fast Kinematic Model of a Seven-Bar Linkage With a Single Compliant Link
Authors: Borboni Alberto , Aggogeri Francesco , Faglia Rodolfo
Published: October 2014

This work deals on a kinematical model of a parallel mechanism for biomedical applications. The mechanism is a linkage composed by three closed loops. It is composed by seven bars (one of them is the frame) constrained each other by ideal constraints (prismatic, rotary or lock joints). The ideal joints introduce 21 degrees of constraint, while the bars produce eighteen degrees of freedom when considered rigid. Six bars are really rigid, while one of them is compliant with respect to the others and allows the mobility of the mechanism. The kinematic of this seven-bar linkage is analyzed with the aim of Hermite’s polynomials. The proposed approach is based on the knowledge of kinematical constraints at the ends of the compliant beam, in terms of position and curvature. This knowledge is based on the fact that the rest of the structure is composed by rigid bodies and ideal concentrated constraints. The compliance affects the beam only with bending effects, furthermore, in this work, we consider only a planar linkage, thus the torsion effect is not considered, and the beam is constrained in ways that compression instability is negligible. Although the beam is subjected to important deformations, it is divided in parts, such that each part is subjected to a small deformation. In this way, we propose the Hermite’s polynomials to describe the shape of the beam. We tested this fast method to describe the kinematical behavior of the system with a kinetostatic model of a mechanical device, finding that it is reliable for the proposed application.
High Precision Machine Based on a Differential Mechanism
Authors: Borboni Alberto , Ceretti Elisabetta , Copeta Alessandro , Moscatelli Davide , Faglia Rodolfo , Attanasio Aldo
Published: October 2014

Micromachining processes deal with the production of parts characterized by features in the micro range (i.e., with dimension lower than 1 mm). Several works are present in literature analyzing the tool behaviors, the material influence on the process, and the machine design. In fact, the downsize of the process up to the microscale needs a full review of all the knowledge coming from the meso and macro scale. As a consequence, machines suitable for micromachining processes were recently introduced in the market.

Usually, these machines are classified by the classical gantry layout structure supported by a granite frame and, in order to guarantee the needed requirements of precision and accuracy in the micro scale, they are based on fluid-supported axes and active and/or passive vibration control systems.

This paper proposes a new concept design: a high precision machine (HPM) based on an innovative layout exploiting a differential mechanism with three motors for two degrees of freedom using pulleys and metal belts. This new layout exhibits relevant advantages. The most significant is that all the worktable servo drives, that moves along x and y axes, are ground-fixed. This allows to isolate the working area of the machine from the servo drives. The system of pulleys and belts holding the working table slides on air bearings in order to minimize the micro vibrations induced by all the drives. A further peculiarity of the machine consists of the double z-axis each of them is motorized by a micrometer slide with linear absolute encoder. The first z-axis is equipped with a spindle for performing micro machining processes (drilling and milling). The second z-axis is equipped with a laser head for micro ablation. The servo drives of the two z-axes are controlled by the same control system of the worktable. Another important feature of the proposed layout is that the differential configuration of the xy mechanism admits the use of a constant speed signal to each control reference with no output displacements. This allows to guarantee non-inversion of motion of the servo-drives and so the avoidance of problems due to backlash and/or static friction. Drives are controlled by position and speed control loops with PID architecture, anti-windup and feed forward strategies. Controllers have been tuned by the use of a genetic algorithm applied to a dynamic model of the system.

As a general consideration, the quality of the investigated micro machining processes can be improved with the designed machine structure.
SCRC Technology for Naval Propulsion
Authors: Wettstein Hans E.
Published: October 2014

Supercharged Diesel engines are nowadays dominating naval propulsion. They have a thermal efficiency up to 50% and can swallow almost any liquid fuel. But there are two main drawbacks:

Nitrogen oxides emissions of Diesel engines are sometimes higher than desired.

Low speed vibrations can often be felt everywhere on the vessel. Some cruising ships therefore use gas turbines in spite of the lower thermal efficiency.

But instead of supercharging Diesel engines also gas turbines can be supercharged. In combination with recuperation they could achieve even a higher thermal efficiency than Diesel engines. Such a concept with the name “Semi-Closed Recuperated Cycle” (SCRC) has been proposed in [1] for replacing gas turbine combined cycles.

This paper shows new results of thermodynamic calculations of the SCRC with adiabatic or intercooled compressors. These calculations are optimized for naval applications with liquid fuels. The state of the SCRC technology is described with its expected operation, control concepts and limitations. Based on this investigation there is good evidence that supercharged Diesel technology for naval application could be seriously competed by the SCRC technology with respect to thermal efficiency, vibration (engine smoothness), emissions and specific mass (per kW power). It is the declared intention of the author to find companies who are interested in developing this technology.
Effect of Inclination Pipe Angle on Oil-Water Two Phase Flow Patterns and Pressure Loss
Authors: Hojati S. Alireza , Hanafizadeh Pedram
Published: October 2014

The flow patterns in two phase and multi-phase flows is a significant factor which influences many other parameters such as drag force, drag coefficient and pressure drop in pipe lines. One of the major streams in the gas and oil industries is oil-water two phase flow. The main flow patterns in oil-water flows are bubbly, slug, dual continuous, stratified and annular. In the present work flow patterns in two phase oil-water flow were investigated in a 0.5in diameter pipe with length of 2m. 3D simulation was used for this pipe and six types of mesh grid were used to investigate mesh independency of the simulation. The proposed numerical analyses were performed by a CFD package which is based both on volume of fluid (VOF) and Eulerian-Eulerian methods. The results showed that some flow patterns can be simulated better with VOF method and some other maybe in Eulerian-Eulerian method, so these two methods were compared with together for all flow patterns. The flow patterns may be a function of many parameters in flow. One of the important parameter which may affect flow patterns in pipe line is pipe inclination angle; therefore flow patterns in the different pipe inclination angles were investigated in two phase oil-water flow. The range of inclinations has been varied between −45 to +45 degree about the horizon. In the presented simulation oil is mixed with water via a circular hole at center of the pipe, the ratio of oil surface to water surface at entrance is 2/3 so water phase was considered as the main phase. Flow patterns were investigated for every angle of pipe and numerical results were compared with available experimental data for verification. Also the flow patterns simulated by numerical approaches were compared with available flow regime maps in the previous literatures. Finally, effect of pipe inclination angle and flow patterns on the pressure loss were investigated comprehensively.
Automobile Driving Control for a Dual Power Electric Vehicle With a Hydrogen Fuel Cell
Authors: Kuo Keilin , Tsao Chungchen
Published: October 2014

In this study, we adopt a dual power system for extension (DPES) operation by combining the existing power system of an electric vehicle with a hydrogen fuel cell. This was to enhance the durability of the electric vehicle and reduce the inconvenience of battery charging. The lithium battery acts as the primary power source and has real-time monitoring of its state of charge (SOC), while the hydrogen fuel cells act as the auxiliary power supply. The auxiliary power can be used either directly or for charging the lithium battery while the vehicle is in its idle state. The dual power system is coupled with a dual-mode motor controller and energy management system. This study aims to apply the dual power system on the electric vehicle using hydrogen fuel cells. We designed a simulation platform for real driving conditions using Labview to send and receive control commands. In this study, we simulated the road cycles of the Economic Commission for Europe (ECE-40), Japanese legislative cycle (JP10) and the World-wide Motorcycle Emissions Test Cycle (WMTC), using Proportional-integral Control (PI) for automatic tracking and employing engineering error analysis to determine the most suitable PI parameter values for the simulated system. The results showed that using a fixed 100 W fuel cell could enhance the operation time up to 21 %, 21 %, and 14 % for the road cycles of the ECE-40, JP10, and WMTC, respectively. Due to the required features of an actual vehicle, we also designed an energy limiting system to manage the driver-controlled electronic throttle by controlling the instantaneous and maximum power output of the motor in order to achieve savings in energy consumption, increase its operation time, protect the system, and enhance its durability.
Dynamic Performance of a Combined Gas Turbine and Air Bottoming Cycle Plant for Off-Shore Applications
Authors: Benato Alberto , Pierobon Leonardo , Haglind Fredrik , Stoppato Anna
Published: October 2014

When the Norwegian government introduced the CO2 tax for hydrocarbon fuels, the challenge became to improve the performance of off-shore power systems. An oil and gas platform typically operates on an island (stand-alone system) and the power demand is covered by two or more gas turbines. In order to improve the plant performance, a bottoming cycle unit can be added to the gas turbine topping module, thus constituting a combined cycle plant. This paper aims at developing and testing the numerical model simulating the part-load and dynamic behavior of a novel power system, composed of two gas turbines and a combined gas turbine coupled with an air bottoming cycle plant. The case study is the Draugen off-shore oil and gas platform, located in the North Sea, Norway. The normal electricity demand is 19 MW, currently covered by two gas turbines generating each 50% of the power demand, while the third turbine is on stand-by. During oil export operations the power demand increases up to 25 MW. The model of the new power plant proposed in this work is developed in the Modelica language using basic components acquired from ThermoPower, a library for power plant modelling. The dynamic model of the gas turbine and the air bottoming cycle turbogenerator includes dynamic equations for the combustion chamber, the shell-and-tube recuperator and the turbine shafts. Turbines are modelled by the Stodola equation and by a correlation between the isentropic efficiency and the non-dimensional flow coefficient. Compressors are modelled using quasi steady-state conditions by scaling the maps of axial compressors employing a similar design point. The recuperator, which recovers the exhaust heat from the gas turbine, is modelled using correlations relating the heat transfer coefficient and the pressure drop at part-load with the mass flow rate. Thermodynamic variables and dynamic metrics, such as the rise time and the frequency undershooting/ overshooting, are predicted. Considering a load ramp of 0.5 MW/s, an undershooting of 4.9% and an overshooting of 3.0% are estimated. The rise time is approximately 30 s. Moreover, findings suggest that decreasing the core weight of the recuperator leads to limiting the frequency fluctuations, thus minimizing the risk of failure of the power system.
Measurement of Film Thickness for Continuous Fluid Flow Within a Spinning Cone
Authors: Symons Digby D. , Bizard Arnaud F. M.
Published: October 2014

This paper reports experimental measurements of film thickness for continuous fluid flow within a spinning cone. The results are compared to analytical theory for thin film flow and found to be in good agreement.

Spinning cones are used in various industrial process machines, including spinning cone distillation columns, centrifugal film evaporators and continuous centrifugal filters. In each case a fluid is fed continuously into the centre of a conical vessel which spins about a vertical axis with the cone apex pointing downwards. The fluid acquires the angular velocity of the cone and migrates up the internal wall of the cone under centrifugal force. Knowledge of the film thickness and flow velocity is often important in order to understand other performance parameters of the process such as evaporation or filtration rates. This paper aims to aid the design of new process machines by providing a mathematical model for film thickness that is validated by experimental results.

Experiments have been conducted in which the angle of cone, angular velocity and input flow rate were all varied. Film thickness measurements were obtained via a novel optical method based on photographing the displacement of a projected grid on the surface of the flow within the cone. The method has the advantages of not disturbing the flow in any way and can provide thickness measurements over the whole cone depth. Measurements are also made insensitive to any transients by use of relatively long photographic exposures.

Measurements are compared to analytical theory for axisymmetric, steady state, free-surface laminar flow of a Newtonian fluid in a spinning cone. The theory assumes the flow is thin but takes account of gravity. The theoretical model is found to be in good agreement with the experimental results.
Reliability Analysis of Automotive Magnetorheological Brake: A Qualitative Approach
Authors: Patil Satyajit R. , Sawant Suresh M.
Published: October 2014

Magnetorheological (MR) brake technology, owing to its reduced response delay, has generated interest for its potential as substitute to conventional hydraulic brakes in a road vehicle. Recently, few investigations have been carried out to assess its application for a mid size car. Finite element studies and experimental investigations have been carried out by researchers. However, reliability aspect of these brakes doesn’t seem to have been explored as yet.

This paper makes an attempt to present findings of the qualitative reliability studies on MR brake system for vehicular application. Results of Failure Mode Effect Analysis (FMEA) and Fault Tree Analysis (FTA) have been presented and discussed subsequently. Findings of this analysis, it is believed, shall complement the design process and make it fool proof. It also provides basis for further quantitative reliability estimation, in case of availability of failure data of MR brake system components.
Bio-Inspired Solutions in Design for Manufacturing of Micro Fuel Cell
Authors: Omidvarnia Farzaneh , Hansen Hans Nørgaard
Published: October 2014

In this paper the application of biomimetic principles in design for micro manufacturing is investigated. A micro direct methanol fuel cell (μDMFC) for power generation in hearing aid devices is considered as the case study in which the bio-inspired functions are replicated. The focus in design of μDMFC is mainly on solving the problem of fuel delivery to the anode in the fuel chamber. Two different biological phenomena are suggested, and based on them different bio-inspired solutions are proposed and modeled in CAD software. Considering the manufacturing constraints and design specifications, the advantages and drawbacks of each proposed solution is discussed. Finally, the most feasible idea, in terms of manufacturing and function, is selected and an initial experimental verification is carried out.
Investigation of MHD Natural Convection Flow Exposed to Constant Magnetic Field via Generalized Differential Quadrature Method
Authors: Baskaya Elgiz , Fidanoglu Melih , Komurgoz Guven , Ozkol Ibrahim
Published: October 2014

In this work, nanofluid flow characteristics of an inclined channel flow exposed to constant magnetic field and pressure gradient is investigated. The nanofluid considered is water based Cu nanoparticles with a volume fraction of 0.06. The viscous dissipation is taken into account in the energy equation and the governing differential equations are nondimensionalized. The coupled one dimensional differential equations are solved via Generalized Differential Quadrature Method (GDQM) discretization followed by Newton Raphson method. Furthermore, the effect of magnetic field, inclination angle of the channel and volume fraction on nanoparticles in the nanofluid on velocity and temperature profiles are examined and represented by figures to give a thorough understanding of the system behavior. Designing systems utilizing nanofluids optimally, is highly dependent to achieving accurate model definitions figuring their inherent performance.
Synthesis of Decoupled Spatial Translational Compliant Parallel Mechanisms via Freedom and Actuation Method (FAM)
Authors: Li Haiyang , Hao Guangbo , Kavanagh Richard
Published: October 2014

This paper introduces a screw theory based approach termed the freedom and actuation method (FAM) to the synthesis of decoupled spatial translational compliant parallel mechanisms (XYZ CPMs) with consideration of actuator isolation (input decoupling). This approach is unique in that (a) actuator arrangement is taken into account; and (b) it is based on a set of rules and mathematical expressions, rather than rigid-body mechanism design experience mainly used at present. According to the rules, XYZ CPMs are firstly decomposed into simple function modules, and the degrees of freedom (DOF) of each function module are identified based on the mathematical expressions. Each function module is then synthesized based only on the DOF without consideration of the actuator arrangement, so existing flexure mechanism design approaches such as the constraint-based design, the screw-theory-based method, and the freedom and constraint topology can be employed for the synthesis of the function module. The synthesis process is finally summarized and demonstrated step by step via a monolithic XYZ CPM design example. It can be envisaged that a variety of configurations of each function module can be derived under a specific DOF. Therefore, one can obtain a great number of XYZ CPM designs with consideration of actuator isolation through changing the structure of each function module, even though there is no any rigid-body mechanism design experience. The proposed FAM will enable designers to (a) decompose XYZ CPMs into the function modules; (b) yield multiple solutions to meet the DOF requirement of each compliant function module; and (c) obtain a variety of XYZ CPMs with consideration of actuator isolation.
Friction of Rough Soft Matter Contacts: Local Investigations Through Image Correlation Technique
Authors: Le Houérou Vincent , Morestin Fabrice , Gauthier Christian , Baietto Marie-Christine
Published: October 2014

The friction induced in contacts is a key feature concerning functionality of mechanisms, reliability of systems, energy consumption… Friction on soft matter occurs in many applications (tire/road contacts, touch-sensitive exploration, micro-manipulation of biological items…) as well as in nature. The latter offers various examples of how a topographic surface pattern may control friction. The result is a complex combination of phenomena: adhesion, elastic ratio of bodies in contact, viscous flow, plasticity occurrence, and topography interaction. The role of this latter phenomenon essentially lies in the splitting of the contact area between the two contacting materials and plays an important role on friction response when coupled with adhesion.
Simulation of Combustion in a Porous Reactor
Authors: Mohammadi Arash , Benhari Mona
Published: October 2014

Development of IC engines with low emissions and low fuel consumption causes interest in direct injection engine, especially diesel engines that work with lean mixture. This goal may be achieved with separation of mixture formation and combustion processes, in diesel engines. A practicable way to reach this target is the use of porous medium (PM) inside the combustion chamber. The PM has benefits to enhance the evaporation of droplets in liquid-fuel burners, reduce emissions and minimize instabilities. This paper represents the numerical study of liquid-fuel injection and combustion inside constant-volume chemically inert PM to stabilize lean mixture. 3D numerical results have obtained based on a modified version of KIVA-3V code. Diesel was directly sprayed inside hot and high pressure PM chamber. Complete evaporation and self-ignited was achieved due to the initial temperature of PM. The results in an especial condition have compared with an experimental data in the literature. Effect of injection in cold condition has investigated. Contours of diesel vapor, fluid and solid temperature of PM in a cross section, have shown. Also, effects of pore density on a constant high-porosity PM and mass of spray fuel were studied. The results show considerable reduction in carbon monoxide, nitrogen monoxide and elimination of soot.
Determining of Optimized Mechanical Characters for Designing of an Artificial Ankle
Authors: Goudarzi Ali M. , Kheirollahi Hossein , Fazeli Mohammad , Imani Misagh
Published: October 2014

Investigating the mechanical behavior of a healthy human ankle shows that it can be simulated by a mechanism composed of simple elements such as spring, and actuator. Hence, appropriate design of this mechanism can be resulted to an artificial ankle that can help amputees properly. Researches show that whatever the biomechanical behavior of artificial ankle is similar to that of natural ankle, it can be used by consuming less energy. Considering biomechanical behavior of normal ankle in a walking gait, required parameters for designing of an artificial ankle composed of springs and electromechanical actuator will be determined. Finally, to verify the suggested model, a prototype will be materialized and tested.
Hemodynamical Aspects of Endovascular Repair for Aortic Arch Aneurisms
Authors: Nardi Asaph , Avrahami Idit , Halak Moshe , Silverberg Daniel , Brand Moshe
Published: October 2014

The presented study is focused on the hemodynamics aspects of thoracic aortic aneurysm and approaches for restoring hemodynamics in the aortic arch. The study includes numerical investigation of the aortic arch hemodynamics of a healthy aorta, aorta with aneurysm, and of two endovascular repairing procedures. The first endovascular repair approach is the total aortic arch hybrid debranching. The second implantation uses chimney graft technique.

The analysis includes the fluid dynamics in the aorta and branching arteries under time-dependent physiological conditions. The results show the effect of aneurysm on blood flow in the descending aorta and in aortic arch side branches. In the aneurysmatic case, the aneurysm provokes a highly disturbed flow and large recirculation regions, especially during diastole. Out of the two endovascular techniques, the hybrid procedure was found preferred from hemodynamics point of view, with less disturbed and recirculating regions.

Although the chimney procedure requires less manufacturing times and cost, it is associated with higher risks rate, and therefore, it is recommended only for emergency cases. This study may shade light on the hemodynamic factors for these complications, and provide insights on ways to improve the procedure.
An Investigation of an Electromechanical Valve Actuator With a Disc Type of Electromagnet
Authors: Kamiş Kocabiçak Zeliha , Erzan Topçu Elif , Yüksel İbrahim
Published: October 2014

This paper presents a disc type of electromagnetic circuit for designing of an electromagnetic valve actuator (EVA). The static and the dynamic equations of the system are derived and their numerical solutions are obtained with MATLAB/Simulink programs. A prototype of the EVA was built and some preliminary tests were carried out on them for static and dynamic tests. The effect of holding current is obtained on the dynamic behavior and energy consumption of the system.
Flight Stability and Safety of WIG Craft With and Without Feedback Control
Authors: Groß Andreas , Kornev Nikolai , Hahn Tobias , Lampe Bernhard , Drewelow Wolfgang
Published: October 2014

The paper presents the motion simulation of a Wing in Ground craft with a Lippisch configuration which is stable in terms of static stability. The influence of wind and wave perturbations on the dynamic stability of the flight are investigated.

The analysis of safety and stability used two different approaches. Based on frequency domain simulation, the first approach derived from the classical stability theory utilizes the aerodynamic coefficients and their linearized derivatives. The second approach based on time domain simulation uses the coefficients with full respect to the nonlinear character of aerodynamics in ground effect. The trajectory is used to evaluate the dynamic stability and flight safety of the craft. From the results for typical perturbations, the limitations of the classical stability theory for the flight safety of Wing in Ground craft are shown.

The results show the necessity of the automatic control system even for a satisfying stable craft predicted by the linear theory. The demand of high performance together with the hard constraints for states and control inputs are challenging for the controller design. A proportional-integral-derivative controller is studied to secure the flight safety of small craft under different perturbation and a methodology for designing a control system for operation under various weather conditions is illustrated.
Using a Conventional Servopneumatic System for Robust Motion Control in the Micrometer Range
Authors: Carneiro J. Falcão , de Almeida F. Gomes
Published: October 2014

Conventional pneumatic systems present several advantages over competitive technologies, as they do not exhibit significant heat or magnetic fields and present high force to volume ratios. Nevertheless, they are very difficult to control due to their inherent nonlinearities like friction forces or air compressibility. As a consequence, their use is limited to simple motion tasks. This paper uses a nonlinear control law, previously developed by the authors, to control a servopneumatic system in the micro meter range. Preliminary experimental results show that the control law leads to very accurate motion control in micro meter positioning tasks in any position of the piston stroke. The paper also shows, through experimental results, that the control law is robust to parametric variations (change of payloads) and to external constant disturbances (gravity force).
Fretting Wear of Coated Surfaces Under Gross Slip Conditions
Authors: Jerbi H. , Nelias D. , Baietto M-C.
Published: October 2014

Blade-disk contact within high pressure compressor, is a high temperature fretting contact zone submitted to high stress levels. Therefore, it is important to estimate the various damages encountered in this area in order to correctly predict the lifetime of the parts. Coatings are used in order to improve the strength of the parts. In the framework of Innolub project, this study aims at developing a numerical model of coated contact accounting for wear and temperature. The objective is to estimate the kinetics of wear, to simulate worn surfaces and to allow the manufacturer to produce analyses of design with worn surfaces using a fast, efficient and reliable method of calculation.
Development of an Experimental Facility Towards Sound Excitation Effects on Forced Convection Heat Transfer
Authors: Cukurel Beni , Selcan Claudio , Shashank Judah
Published: October 2014

In light of the potential of acoustic excitation for heat transfer enhancement, the research effort herein is geared towards a better understanding of the underlying physical mechanisms of aero-thermal laminar and turbulent boundary layer development under the influence of directed sound excitation. An experimental measurement campaign is carried out throughout which the effects of small amplitude periodic flow oscillations on convective heat transfer in straight channels are investigated. A low velocity wind tunnel facility has been designed and built for this purpose. Measurements of convective heat transfer are conducted by means of steady wide band liquid crystal thermometry at several acoustic and aerodynamic parameters. The findings of this investigation indicate that modification of convective heat transfer by directed sound excitations is possible. Dependent on the source frequency, the net effect can be a heat transfer augmentation or a local reduction. Although the acoustically induced changes are small in magnitude, the dependence on the excitation frequency is still quantifiable beyond measurement error.
Stent vs Stent Study by Means of Finite Element Method
Authors: Imani Misagh , Goudarzi A. M. , Ganji D. D. , Gerdroodbary M. Barzegar
Published: October 2014

It is well known that the stent design plays an important role in the outcome of the stenting interventional procedure. Thus, analyzing and comparing the behavior of different types of stent is essential to select the most appropriate stent design to use. Furthermore, assessing the behavior of stent is one of the components of the process in which new biomedical stent devices are designed and approved. Indeed, new stent designs have to be proved to be equivalent to an approved stent to be confirmed from the regulatory agencies. This sets the stage for a series of “stent versus stent” randomized trials designed to show that each newer stent design was not inferior to the prior approved stent. In this paper, finite element method is used to assess the behavior of stents. The objective of this work is to present a numerical alternative for “stent versus stent” complicated clinical studies. Three commercially available stents (the Palmaz–Schatz, Multi–Link and NIR stents) are modeled and their behaviors are compared. According to the findings, the possibility of restenosis is lower for Multi–Link and NIR stents in comparison with Palmaz–Schatz stent which is in good agreement with clinical results.
New Fault Tolerant Hydraulic Valve for Safety Critical Applications
Authors: Ruggeri Massimiliano , Marani Pietro
Published: October 2014

The paper deals with a new concept hydraulic spool valve. The new patented valve presents a secondary rotary type actuator connected to a sleeve interposed between the spool and the valve body, thus composing a roto-translating valve. The sleeve presents holes that can be moved and positioned partially or totally overlapped to the valve ports, thus allowing a secondary metering, that can be controlled according to the spool position. The valve port area is then related to the movement of the spool, and to the rotary movement of the cylinder, controlled by a different type of motors. The valve port area is the result of two actuators position, and the resulting control is linearly depending by two PWM signals, both controlled by a microcontroller based unit. Due to the valve structure, the metering control precision is virtually quadratic in respect to the traditional valve spool position electronic control, due to the concurrency of two electronically controlled actuators. Similar considerations could be done for the valve speed, due to the concurrent speed of two different actuators. Another big advantage is the lack of need of special spool design for different applications, due to the possibility offered by the two actuators control. The valve can realize both basic logic functions (AND, OR), and advanced control techniques; moreover in term of safety it offers a fail operational characteristic, in reason of an operational redundancy and functional diversity.
Development and Comparison of Laplace Domain Models for Non-Slender Beams and Application to a Half-Car Model With Flexible Body
Authors: Van Auken R. Michael
Published: October 2014

Math models of flexible dynamic systems have been the subject of research and development for many years. One area of interest is exact Laplace domain solutions to the differential equations that describe the linear elastic deformation of idealized structures. These solutions can be compared to and complement finite order models such as state-space and finite element models. Halevi (2005) presented a Laplace domain solution for a finite length rod in torsion governed by a second order wave equation. Using similar methods Van Auken (2010, 2012) presented a Laplace domain solution for the transverse bending of an undamped uniform slender beam based on the fourth order Euler-Bernoulli equation, where it was assumed that rotary inertia and shear effects were negligible. This paper presents a new exact Laplace domain solution to the Timoshenko model for an undamped uniform non-slender beam that accounts for rotary inertia and shear effects. Example models based on the exact Laplace domain solution are compared to finite element models and to slender beam models in order to illustrate the agreement and differences between the methods and models. The method is then applied to an example model a half-car with a flexible body.
Analysis of a New Measurement System of the Chain Strength for Electrically Assisted Bicycles
Authors: Abagnale Carmelina , Cardone Massimo , Iodice Paolo , Strano Salvatore , Terzo Mario , Vorraro Giovanni
Published: October 2014

This paper presents an activity concerning a theoretical/experimental analysis of a new measurement system of the chain strength functional for the control of the electrically assisted bicycles. Such systems are characterized by a driving torque due to the contribution of an electric motor and of the rider. The electrical assistance is commonly regulated taking into account informations such as chain ring rotation, bicycle speed and/or the torque given by the rider. As a consequence, suitable measurements have to be made on board in order to handle the assistance performances and to improve drivability.
Jewelry Fabrication via Selective Laser Melting of Glass
Authors: Fateri Miranda , Gebhardt Andreas
Published: October 2014

Selective Laser Melting (SLM) is one of the Additive Manufacturing (AM) technologies applicable for producing complex geometries which are typically expensive or difficult to fabricate using conventional methods. This process has been extensively investigated experimentally for various metals and the fabrication process parameters have been established for different applications; however, fabricating 3D glass objects using SLM technology has remained a challenge so far although it could have many applications. This paper presents a summery on various experimental evaluations of a material database incorporating the build parameters of glass powder using the SLM process for jewelry applications.
Integration of Topological and Functional Optimization in Design for Additive Manufacturing
Authors: Tang Yunlong , Hascoet Jean-Yves , Zhao Yaoyao Fiona
Published: October 2014

Additive manufacturing (AM) technologies has brought unprecedented freedom to the fabrication of functional parts with high complex, multi-material and gradient density structure. However, currently only traditional design methods are available for AM design process, which do not take full advantage of AM capabilities. Therefore, a new design method with the consideration of all aspects of AM advantages is urgently in need. A detailed literature review on traditional design methods is presented with focused attention on the potential of using these methods to design functional parts for additive manufacturing processes. Based on thorough understanding and comparison of current structure design methods, a new design approach that integrates topological and functional optimizations for AM products is presented. With this method, an essential link is established between topological optimization result and various functional parameters of complex structure. Parts can be designed in multi levels for multi functions simultaneously. This design method provides an important foundation for future research on designing AM products with improved multiple functions and optimized topology.
Visualising, Analysing, and Managing the Design Factory
Authors: Sinha Apurva K. , Weaver Matt , Morgan Stephen G.
Published: October 2014

In this paper, we present a framework to define, visualise, analyse and manage a design factory in a complex engineering environment. Design engineering is the core of product development and provides high leverage in cost, quality and time to market. Lean principles can be applied to gain these improvements to the design management system. However, unlike manufacturing and operations, design processes are inherently non-linear and iterative in nature. In addition, design outputs, queues and work in progress are not visible and tangible. This creates challenges in applying lean principles in the design environment. To alleviate these issues design engineering is treated as a factory and its key steps are mapped by using the gated review process. The inputs and outputs of the design factory system are identified and employed to create an effective productivity improvement dashboard. The gated review process steps are used to understand the flow of design solutions. Lean principles and structured root-cause analysis is used to create a system to visualise, analyse and manage the design factory.
Experimental Analysis of NC Fibers Sedimentation After Dehydration Process in Propellant Production
Authors: Martinez-Pastor Juan , Franco Patricio , Moratilla Domingo
Published: October 2014

During the manufacture of energetic materials, the dehydration process of nitrocellulose doughs provides a residual liquid mixture consisting of water, alcohol and nitrocellulose (NC) fibers. The separation of such fibers is required for distillation of alcohol, in order to make possible its reutilization in subsequent processes. In this work, an experimental analysis of sedimentation mechanisms of NC fibers contained in the fluid mixtures from nitrocellulose plants, is presented. The goal of the work is to obtain the time periods needed for complete sedimentation of these solid fractions (NC fibers). Cylindrical tanks with vertical or horizontal orientation are considered in this study, and the results obtained for both tank configurations are compared. From the experimental observations about sedimentation mechanisms of solid fraction in these fluid mixtures, recommendations about optimum times for NC fibers removal are proposed. These optimum times should be assumed as basic guidelines for scheduling and execution of the distillation process, due to its high influence on minimization of the overall operational costs for this process. Great discrepancies were registered between sedimentation times of NC fibers in vertical or horizontal tanks, with reductions in sedimentation rate of until 40% for recipients located in vertical orientation.
Special Design Consideration for Agitators With Example of Repeated Breakdowns
Authors: Thomas Samuel M.
Published: October 2014

The repeated failure of Agitator in the Phosphoric acid Reactor in MPC was a major incident causing high downtime and production loss. While doing the root cause analysis of this “Class A” incident many causes not considered in normal agitator design were considered and analyzed. This paper lists such special cases and the proposed solutions and calculations to be incorporated in design of critical systems with varying process fluid parameters for different applications. Agitators constitute almost 20% of rotating equipment in a fertilizer and similar plants but are given less priority compared to others until a severe failure happens. There are no standard analytical design criteria for agitator design due to large variations and uncertainties in the process conditions in the reactor or tank. Most designs are left to the EPC companies using preformatted design models based on experimental results, on the combination of few variables. (Like Power Number, Pumping Number, Geometrical ratios etc.) However, none these models considers the fluid flow conditions which changes inside the reactor which affects the agitator design in many ways like Localized flow, non-homogenous fluid, solid contents, Liquid additives or recycling etc. which can cause much higher alternating forces and bending stresses at the joints holding the blades causing fatigue and other failures. This paper gives more quantitative design calculations to determine the forces acting on the agitator and blades as listed above which can be used in similar application even with different fluids.
Exact Solutions of a Class of Two-Phase Stefan Problems in Heterogeneous Cylinders and Spheres
Authors: Layeni Olawanle P. , Ilori Olusoji , Ajayi Ebenezer O. B.
Published: October 2014

The classical Stefan problem proffers a suitable model for determining the temperature regimes as well as conjugate interfacial positions for multiphase problems. Obtaining the solutions to these problems exactly, especially in systems with cylindrical or spherical symmetry, is often an arduous task. This is largely due to inherent nonlinearities in the mathematical statements of Stefan problems.

In this paper, a tractable and effective approach is proposed. Subsequent to a recast as a system of differential-difference equations, and a methodical reduction to constant coefficient difference equations, exact similarity solutions are derived for a class of heterogeneous two-phase Stefan problems with cylindrical or spherical symmetry in one spatial dimension, under either Gaussian or hypergeometric perturbations.
Analysis of Static Strength and Failure Mode of FSSW Joint in Aluminum Alloy
Authors: Vivio Francesco , Vullo Vincenzo , Fanelli Pierluigi
Published: October 2014

In this paper an analysis of Friction Stir Spot Welds (FSSW), applied to lap joint aluminum alloy is presented. The analyses regards the structural behavior of FSSW joints in order to assess the failure mode and its dependence on mechanical properties distribution of the sheets material and, consequently, on process parameters.

FSSW joint is analyzed by means of a complex 3D FE model, which allows to evaluate, in a parametric manner, the multifaceted internal geometry of the joint and the actual distribution of material mechanical characteristics after welding. Experimental tests allowed to verify the results and to calibrate the material characteristics in the FE model.
Static Analysis and Strength Reliability of Human Femur Bone
Authors: Yakkala Viswanath , Ahmad Suhail , Mahajan Puneet , Pankaj Pankaj
Published: October 2014

The neck portion of the human femur is the most vulnerable region to attract stress-induced fractures. The loads of the human body act on the hip joint and on the greater trochanter region through abductor muscles. The bone is a natural composite and a good example of functionally graded material (FGM). This study considers a probabilistic finite element approach to assess the critical stresses in the femur under static loads. Material properties assigned to the bone model are linearly elastic, isotropic and orthotropic. Material characterization in terms of bone density is established by Computed Tomography (CT) data. The strength reliability and safety margin are obtained using relevant limit state function. Sensitivity analysis with respect to random parameters provides basis for a possible implant material characterization.