bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Tomographic Reconstruction for Microscale Object Modeling
Authors: Jin Kyung-Chan , Lee Sung-Ho , Kim Geon-Hee
Published: March 2016

When scanning a relatively high resolution, thick object using conventional computed tomography (CT), the scanning axis of the X-ray gantry and detector is approximately perpendicular to the rotation axis of the sample. However, the inner interconnections in flat 3D devices are not reconstructed correctly in regular circular CT. In this paper, we focus on 3D tomographic reconstruction of inner interconnections by CT with particular attention to off-centered circular trajectory CT. However, in off-centered circular trajectory CT, the limited tilting angles of projections result in a missing wedge artifact because the object cannot usually be tilted beyond the limit and the data in the remaining projections are not obtained. Therefore, to alleviate missing wedge artifacts, we propose a reconstruction scheme of combining by filtered back projection (FBP) and constraint-based total variation minimization (c-TVM). In the c-TVM method, the artifact of missing wedge is minimized and the reconstructed region is suppressed with high frequency details while leaving the boundaries between homogeneous regions. In our experiments, the CT system obtained the projected images from a rotating sample using a fixed-mounted X-ray source and detector. We acquired 400 rotational projection images of a vertical connection in an off-centered circular trajectory with 30° tilting angles. We then reconstructed the aligned 3D views of the sample. Finally, we demonstrated that the proposed FBP and c-TVM combination with iterative processing yields a superior 3D reconstruction model to conventional tomography.
Evaluating the Roll Stability of Articulated Vehicles Using a Phase-Plane Analysis Method
Authors: Sun Tao , He Yuping
Published: March 2016

An innovative phase-plane analysis method is proposed to assess the roll stability of articulation vehicles. It is well know that the roll instability of articulated vehicles is one of the most serious problems resulting in loss of life and property for drivers. Hence, it is necessary to develop active anti-roll systems to enhance the roll stability of articulated vehicle systems. In order to actuate the active anti-roll control for the articulated vehicle system, effectively threshold values should be determined. Conventionally, vehicle units’ lateral accelerations are used as the roll-over threshold values for active anti-roll control of articulated vehicles. Considering distinguished configurations and unique dynamic features of articulated vehicles, it is questionable whether the lateral-acceleration-based roll-over threshold of single vehicle is effective to evaluate the roll stability of articulated vehicles. In order to address the problem, case studies will be conducted to assess the roll stability of articulated vehicles using the phase-plane method. To this end, this paper will select a car-trailer system, which is represented by a nonlinear vehicle model generated using the CarSim software package. The phase-plane analysis method is used to examine the following relationships between: 1) the leading unit’s roll angle and roll angular velocity (ϕ – dϕ/dt) and 2) the trailing unit’s roll angle and roll angular velocity (ϕ′ – dϕ′/dt). Built upon the conventional phase-plane analysis method for single-unit vehicles, an innovative phase-plane analysis technique is developed in order to effectively assess the roll stability of articulated vehicles. The applicability and effectiveness of the newly developed technique is examined and demonstrated.
The Research of Noncircular Bevel Gears’ Undercut Condition
Authors: Wang Rui , Shi Kan , Xia Jiqiang , Geng Chunming
Published: March 2016

Noncircular bevel gear (NBG) is a kind of gear which can transmit spatial variable transmission ratio motion directly. It has the advantages of compactness, smooth motion, and accurate transmission. There, however, exists an urgent problem that the NBGs’ exact undercut condition is unknown. The planar noncircular gears’ undercut condition has been researched in different ways, yet the undercut condition research of NBGs is very limited [1–3]. This paper mainly aims at analyzing the undercut phenomenon with tooth profile curve evolute and finding an easy method to judge undercut. The research of this problem is meaningful because it reveals the essence of undercut in an analytical and intuitionistic way and consequently does help to judge the occurrence of the undercut of any teeth. Besides, the proper module chosen according to the undercut judging method will improve the contact ratio of NBG pairs which is good for the meshing property and bearing capacity. This paper is mainly based on analytical and computational methodology. Firstly, for a pair of NBGs, the included angle of pitch curves’ mutual tangent arc and teeth’ normal arc is researched. It can be proved that the included angle is a constant one and is equal to the tool’s tooth profile angle. It should be emphasized that the tool is limited to rack and bevel gear shaper cutter only. Then, the evolute of the tooth profile curve is researched. By analyzing the geometric and kinematic relationship between tooth profile curve, pitch curve and pitch curve’s evolute, the tooth’s every center of curvature can be calculated with the sine and cosine formula of spherical triangle. In other words, the evolute equation is derived. Also, the critical point of undercut can be calculated since the tooth profile curve’s evolute is the generative curve of the tooth profile, which means the intersection of the two curves is the critical point. Rack and bevel gear shaper cutter are discussed separately. The critical point is analyzed in spherical triangle to calculate the critical module value so that the occurrence of the undercut can be judged. Lastly, evolutes of high order spherical ellipses with specific condition are calculated with Matlab and their figures are demonstrated which can reveal the property of evolute directly. The critical module value of a pair of NBGs is calculated and their 3D models are generated by UG. It turns out that no undercut happens. The kinematical simulation is implemented in ADAMS. The actual angular velocity curve of the driven gear is very close to the ideal one. These results justify the correctness of undercut judgement method.
The Design Build Go Universal Power Hub
Authors: Coucci Alexander W. , Grandinetti Marcus R. , Leandro Trevor J. , McCusker James , Williamson Simon
Published: March 2016

The Design, Build, Go Hub (DBG) is a universal power hub that not only encapsulates the various branches of robotic engineering, but also transforms a student’s creativity into a physical product. The hub serves as both control mechanism and the power delivery system for student designs. The universal design is easily implemented to provide automation to designs including quadcopters, wheeled platforms, and mechanized robotics. This hub gives students the opportunity to gain exposure to electrical, mechanical and systems engineering, as well as how the various disciplines can be integrated into a cohesive design. Powered by a Raspberry Pi 2 microcontroller with a motor controller interface, the DBG Hub can interface with a variety of sensors, motors, servos, cameras and various other electrical components.

The mechanical system also has a vast number of possibilities by utilizing rapid prototyping such as 3D printing, vacuum forming, and machining. The DBG Hub was designed to be capable of receiving a vast amount of rapid prototyped parts for nearly any type of mechanical function. The housing, which holds the electrical system, is also a product of rapid prototyping technology. The 3D printed design allows users to create attachments with corresponding electrical components that plug into the housing for a variety of projects. The combination of rapid prototyping with the microcontroller allows the hub to take full advantage of combining the mechanical design with the electrical components. This combination is used to create systems that can sense, think and react.

Sample projects created utilizing the DBG hub as the central control unit, such as the DBG quad-copter, or the DBG land vehicle, perfectly showcase these attributes in an introductory manner. These sample projects have been designed and software created as introductory tools for students interested in engineering. The effectiveness of the hub being able to interest students in engineering will be the subject of a future study. This study will show how simplifying the incorporation of multiple engineering disciplines into one easy to use tool is the simplest and most efficient way to become more knowledgeable of the engineering field. While this study has not yet been conducted, it can still be stated that the DBG Hub is an original and groundbreaking design that will excite, promote, and, most importantly, educate students in the field of engineering.
Visualization of Steam Flow Condensation in Hydrophobic and Hydrophilic Mini-Gaps
Authors: Chen Xi , Derby Melanie M.
Published: March 2016

An experimental, flow visualization study was conducted for flow condensation in 1-mm diameter mini-gaps with a visualization window. The hydrophilic channel was composed of bare copper, while the hydrophobic channel was coated with Teflon AF™. An open loop steam experimental apparatus was constructed, and single-phase validation tests are presented. For flow condensation in the hydrophilic gap, filmwise condensation was observed for all cases with a mass flux range of 30–100 kg/m2s. In contrast, the hydrophobic channel promoted dropwise condensation at mass fluxes of 30 and 50 kg/m2s. Cycles of droplet nucleation, growth and coalescence, and sweeping were identified at both mass fluxes in the hydrophobic channel at steady state. Droplets departed at a smaller sizes and more frequently at the higher mass flux, demonstrating the effects of shear forces on droplet sweeping. Based on flow visualizations, three droplet sweeping methods were identified: interfacial shear stress, upstream droplets, and absorbing into rivulets.
A Mathematical Model With Preliminary Experiments of a Gyroscopic Ocean Wave Energy Converter
Authors: Murakami Hidenori , Rios Oscar , Amini Ardavan
Published: March 2016

Global attempts to increase generation of clean and reproducible natural energy have greatly contributed to the progress of solar, wind, biomass, and geothermal energy generation. To meet the goal set by the Renewable Portfolio Standards (RPS) in the United States, it is advisable for several of the coastal states to tap into the least explored resource: ocean-wave energy. There are many advantages to ocean-wave energy generation. First, the energy per unit area is 20 to 30 times larger compared with solar and five to ten times larger when compared to wind energy. Second, waves are more easily predicted than wind. Currently, there are several challenges with capturing ocean energy: With respect to the environment, noise pollution and effects on marine life need to be taken into consideration; with respect to design, ocean-wave power generators need to withstand large waves due to hurricanes and be designed to lessen visual pollution.

There are various methods and devices used to capture ocean wave energy. Point absorbers, such as PowerBuoy, can harness vertical or heaving motion into electricity while attenuators like Pelamis use the induced movement of its joints from the incoming waves. Unfortunately, many have few parameters that can be varied to optimize power generation and or suffer from the various challenges mentioned above. The gyroscopic ocean wave energy converter harnesses the rocking or pitching motion induced by the ocean waves and converts it into rotary motion that is then fed to a generator. Furthermore, it is a fully enclosed floating device that has several parameters that can be varied to optimize power output. Previous work has demonstrated the viability of such a device, but the theoretical modeling of these converters is still in its infancy compared to that of other ocean wave energy converters. The objective of the research presented is to fully understand the mechanisms of power generation in the gyroscopic ocean wave energy converter. Using the moving frame method, a mathematical model of the device is developed. The nonlinear equations of motion are derived through the use of this novel method and then solved numerically. The results are then used to optimize the system and identify key parameters and their effect on the output power generated. Additionally, the resulting equations serve as a tool for identifying an appropriate control strategy for the system. Finally, a scale model of a gyroscopic ocean wave energy converter is developed to validate the equations of motion that have been derived.
Extension of U* Index Theory to Nonlinear Case of Load Transfer Analysis
Authors: Pejhan Khashayar , Wang Qingguo , Wu Christine Q. , Telichev Igor
Published: March 2016

Load transfer analysis has been proved to be an effective approach for designing light weight vehicle structures in last two decades. There are two main procedures for predicting the load path in a vehicle: The stress trajectory method and the U* index theory. The first approach has shown some shortcomings in dealing with geometrical irregularities. As a result, automotive industries have mainly applied the U* index as a design tool to study the load transfer behavior in the vehicle structure. The U* index, is an indicator for the load transfer in the structure, i.e. higher U* index value indicates more significant role in the load transfer process. So, the distribution of the U* index in the structure can be used to predict the main load path in the structure. Nevertheless, this foundation of this theory is based upon the linear elasticity equations and consequently, it has always been limited to linear elastic problems in static or quasi static conditions. Eradicating this limitation and extending the U* Index theory to nonlinear elastic problems is the main objective of this study. An extension to nonlinear criteria for U* index theory is proposed in this paper. It is shown, for the very first time, that the extended nonlinear load transfer index (U*NL) is a true measure for the load transfer in the structure in a nonlinear elastic problem.
Roll-to-Roll Microcontact Printing of Flexible Aluminum Substrates Using Octadecylphosphonic Acid (ODPA)
Authors: Merian Chris , Du Xian , Hardt David , AlQahtani Hussain
Published: March 2016

Soft-lithography, or the printing of self-assembling molecular inks at micro or sub-micron scale holds the promise of large-scale surface patterning for a variety of applications. One key to the ultimate utility of this concept is continuous roll-to-roll printing on lost-cost flexible substrates. Accordingly, this paper discusses the basic processes involved in roll-to-roll printing of octadecylphosphonic acid (ODPA) on aluminum-coated PET substrates using novel cylindrical stamps cast from PDMS. In addition to printing, visualization of the pattern is achieved through controlled condensation of water vapor and by a post-printing acid etch. By using a roll-to-roll configuration, along with continuous stamps and measurements that can permit real-time online quality monitoring, this method represents a significant step forward in making soft lithography a commercially viable process.
Unusual Heat Transfer Characteristics of Supercritical Carbon Dioxide
Authors: Pidaparti Sandeep , Jarahbashi Dorrin , Anderson Mark , Ranjan Devesh
Published: March 2016

Heat transfer mechanisms in supercritical fluids is quite different due to the fact that the thermophysical properties vary drastically within a span of few degrees Celsius near the critical point. A series of integral experiments were performed to investigate the unusual turbulent heat transfer characteristics of supercritical carbon dioxide flow in round tubes under heating conditions. Wall temperatures were measured over a range of experimental parameters that varied fluid inlet temperature from 20° C to 60° C, operating pressure from 7.5 to 10.2 MPa, mass flux from 100 to 1000 kg/m2-sec and a maximum heat flux of 100 KW/m2. Measurements were made for horizontal, upward, and downward flow to study the effects of buoyancy and flow acceleration caused by large variation in density. Existing criteria to predict the influence of buoyancy suggested that the experimental data can be classified into three regimes, namely normal, deteriorated, and enhanced heat transfer. Localized deterioration in heat transfer was characterized by a sharp increase in wall temperature and observed mainly in the case of upward flow due to reduction in the turbulent shear stress. Enhanced heat transfer regime was characterized by smooth variation in wall temperature and observed in the case of downward flow due to increase in the turbulent shear stress. Flow stratification occurred in horizontal flow resulting in a circumferential variation in wall temperature. Thermocouples mounted 180° apart on the tube revealed that wall temperatures on the top side are significantly higher than the bottom side of the tube. When the bulk temperature is much higher than the pseudocritical temperature, normal heat transfer was observed for all three tube orientations indicating that the buoyancy effects were negligible. Deterioration and enhancement in heat transfer were also observed in downward and upward cases respectively due to the flow acceleration effects. This occurred in the cases where outlet fluid density was much lower than the inlet fluid density causing the flow to accelerate. In the case of upward flow, this acceleration enhanced the turbulent shear stress and heat transfer. The large experimental database was used to evaluate the existing popular heat transfer correlations for supercritical fluids.
On the Scaling of Bubble Cluster Collapse in Cloud Cavitating Flow Around a Slender Projectile
Authors: Wang Yiwei , Huang Chenguang , Wu Xiaocui
Published: March 2016

The scaling law of bubble cluster collapse in cloud cavitating flow around a slender projectile is investigated in the present paper. The influence of compressibility is mainly discussed. Firstly the governing parameters are obtained by dimensional analysis, and the numerical method is established in order to verify the similarity law and obtain the influence of parameters based on a mixture approach with Singhal cavitation model. Moreover, the similarity law is validated by numerical simulations. Two main factors of compressibility of mixture fluid, including compressibility of non-condensable gas and phase change, are studied, respectively. Results indicated that the phase change has little influence on both flowing and collapse pressure. In the condition that the variation range of the mixture compressibility is small, the compressibility of non-condensable gas has notable impact the local collapse pressure peaks, however the macroscopic flow pattern does not change.
Phase Change and Magneto-Rheology of a Suspension Composed of Magnetic Rod-Like Particles
Authors: Satoh Akira
Published: March 2016

Magnetic particle suspensions have a great potential as an application in engineering fields and therefore a variety of studies on these functional fluid have been conducted in various fields, including the traditional fluid engineering field and the recent bioengineering field such as an application to a drug delivery system. The main application target in the fluid engineering field may be mechanical dampers and actuators. Magneto-rheological properties significantly depend on the formation of aggregates of magnetic particles. In the present study, we focus on a ferromagnetic rod-like particle suspension to discuss the phase change of aggregate structures of magnetic rod-like particles and the magneto-rheological properties that are strongly dependent on the formation of aggregate structures. The characteristics of the phase change are mainly investigated by Monte Carlo simulations for thermodynamic equilibrium and the magneto-rheological properties are done by Brownian dynamics simulations in a simple shear flow situation. From the latter simulations, we discuss mainly the dependence of the magneto-rheological effect on the phase change of aggregate structures. In a weak applied magnetic field, magnetic rod-like particles tend to aggregate to form raft-like clusters if the magnetic particle-particle interaction is much stronger than thermal energy. If the magnetic field strength is increased, these raft-like clusters drastically dissociate into single-moving particles at a certain value of the magnetic field strength, that is, the phase change in aggregate structures arises. The net viscosity and viscosity components exhibit complex dependence on the magnetic field strength, which is mainly due to the raft-like cluster formation of magnetic particles.
Computer Assisted Design and Analysis of Shedding Mechanism of Powerloom Machineries
Authors: Sundaram Karibeeran Shanmuga , Prakash M. , Alaguraja Ramachandiran , Radhakrishnan Muruganandhan
Published: March 2016

Cloth has always been the most worldwide of all imported and exported commodities. It is an enlightening example of the movement of knowledge, skills, goods and investment across wide geographic seats. South Asia has been dominant for making of these worldwide interactions over period. This capacity grants advanced research that discovers the dynamic ways in which various textile production and trade regions generated the ‘first globalization’. A series of specialists connect this worldwide commodity with the dramatic political and economic alterations that characterised the India in the recent centuries. Together, the papers transform our understanding of the contribution of South Asian cloth, specifically Indian cloth to make the modern world economy. India is the largest share of its exports being textiles and apparels to the world. Also weaving is second only to agriculture sector in terms of providing employment in India. This paper a simple spreadsheet program method of calculations for the complete kinematics and dynamic analysis of the shedding mechanism of the classical powerloom is presented. Shedding is one of the important processes used in weaving technology of textile machineries. Most of the powerlooms of India uses staubli’s M5 module for shedding. These modules are activated through the traditional slider-crank mechanism. The source energy for these modules is through electric motor coupled with clutch and resulting output is shedding action of warp threads of cloth. Objective of this work is to address the kinematics and Dynamics simulation of linkage assembly of shedding mechanism of textile machinery considering all the links of the model as rigid one. Also this paper examines the effect of dynamic forces on various joints of conventional kinematic model. Subsequently the optimisation of mechanism is carried out by varying the design factor ratio of the slider crank mechanism. Length of connecting rod to radius of the crank shaft has been taken into account for defining design factor ratio for the analysis. Altered varieties of models having various design factors are modeled using 3D modeling package Solidworks. Simulation test results and force analysis of these models were carried out using ADAMS. Being a single degree of freedom mechanism as defined by its crank angle, the spreadsheet program can be used to answer what - if? situation queries through tables and graphical plots to evaluate variations of key motion and loading parameters with changes in the design factor. Thus, it allows for the conduct of parameter studies in selecting optimum crank-and-connecting-rod linkage dimensions and speeds. Thus, this work provides an alternative solution and scope for further research in shedding mechanism’s simulation analysis.
Modification of Doublet Modes in a Circular Disc Constrained by Cyclic Symmetric Features
Authors: Tsai Sung-Han , Chang Jen-Yuan (James)
Published: March 2016

From design perspective, structural modification including material modification and geometry modification in a brake system is the most common approach in reducing the brake squeal. Research of this paper will focus on the modification of the largest noise-generating part in motorcycle’s brake system-the circular disc rotor, based on an existing product available in Taiwan. To reach the best geometry design of a circular disc rotor for specific vibration reduction criteria, parametric studies will be carried out in understanding effects of two evenly distributed modifications in the disc — the bolts and ribs. This paper aims to find a criterion in dealing with the design of a pattern on a disk through finite element analyses and experimental modal analyses. From which results, a new criterion for frequency splitting is developed and a mode-veering phenomenon is observed. The outcome has engineering application in reducing specific squeal noise caused by split doublet modes and shifting natural frequencies of a brake disc without creating a new one.
Optimized Design of Structural Components Realized Through Additive Manufacturing
Authors: Baglioni Stefano , Braccesi Claudio , Cianetti Filippo , Conti Paolo , Rossi Gianluca
Published: March 2016

Nowadays Additive Manufacturing (AM) is going through a very fast development, spreading in many different mechanical contexts. The main advantages of this technology are: production costs reduction (prototype realization time reduction, raw material consumption reduction, almost zero manpower needed...), significant reliability (compared to the standard production process) and last but not least extreme freedom in product shape design. The last characteristic makes it possible to adopt new design approach focusing on component shape and material distribution optimization; a new design paradigm must be developed to fully take advantage of these opportunities: the designer can develop new concepts with very complex shapes and sophisticated topological solution owing to opportunities yielded by AM with in mind only the week limitations given by this technology.

In detail this work aims to highlight a new design strategy that consist of a combination of structural optimization tools (Topology Optimization TO) and non-contact stress field measurement technique (based on thermo-elasticity). The goal is to develop an iterative design procedures which links the design shape optimization with the experimental stress evaluation, allowing a wise material distribution in order to enhance the resistance.

The idea is to accomplish an initial designing phase, letting the designer free to define a first rough design concept taking into account the information provided by the TO to exploit the material in the best way. Then, the concept must be verified in both: model numerical F.E.M. analysis and prototype experimental evaluation of the stress field. Eventually, according to the verification analysis results, the model will be modified to reach the desired requirements in terms of allowed deformation, stress resistance and fatigue life.

The paper will display the optimization technique iterative process (based on Solid Isotropic Material with Penalization – SIMP – scheme) in a general way and through a practical example. As a reference, this methodology has been applied to a specific test case in order to design and optimize a new concept of a structural mechanical component of a mountain bike. The component was, first realized as a prototype in thermoplastic material and finally designed to be realized in metal for in field application.
Analysis and Optimization of a Spring Based Clamping System
Authors: Landi Luca , Braccesi Claudio , Cianetti Filippo , Lucertini Simone
Published: March 2016

Clamping systems based on a spring mechanism are widely used in tooling machine industry due to its simplicity, low cost and high reliability.

This paper explores the theoretical formulation of a general clamping mechanism based on direct spring actuation, in terms of the two different requirements: a proper clamping force and a limited maximum stress for a better fatigue duration.

First the influence of the main “key design parameters” on the mechanism characteristic will be recovered, the results show clearly that, the simple re-engineering of typical solution does not meet the requirements for a new multi-purpose tooling machine.

Moreover the improved performance obtainable for the clamping system using a “preloaded mechanism” will be evidenced thorough an analytical formulation taking into account the different behaviors of the mechanism during the preloading phase and the clamping phase.

The goodness of the new analytical model will be verified through analytical and FEM non-linear model comparison for an industrial clamping system based on a flexural spring both in terms of clamping force and of fatigue durability.
Experimental Investigation of Thermal Properties of Hybrid Glass Fiber-Sisal Reinforced Epoxy Composites
Authors: Palanikumar K. , Prabhudass J. M. , Sailesh Ashwin
Published: March 2016

Composite materials are preferred in all engineering applications, because of their superior properties over the traditional materials. Among composite materials, Natural fiber reinforced polymer finds rapid development in industrial applications and many areas of research. In this paper, thermal properties of Sisal-Glass fiber reinforced epoxy composites are studied to assess the influence of different fiber orientation. Thermal properties of the composite are analyzed using Thermo Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) to investigate the influence of change in fiber orientation.
Effect of Paper Property on Mechanical Property of Paper Tube
Authors: Suda Mitsunori , Kitamura Takanori , Wongpajan Ratchaneekorn , Zhang Zhiyuan
Published: March 2016

Paper recycling is an effective way in reducing deforestation and energy consumption. Therefore recycling paper and paper products has been widely applied in many areas, such as packaging industry, film rolls, adhesive-tape industry, furniture decoration and temporary structures in building. They can be produced into various structure according to different requirement, such as paper tube, corrugated paperboard and normal paperboard. Paper-tubes gain more and more applications as a traditional structure due to their excellent mechanical property and environmentally friendly property. In order to meet various needs of paper-tube and produce high performance paper-tubes, designing for paper-tubes fabrication is needed. It is necessary to research the lateral compression strength of paper tube because various paper-tubes are used as packages, cores, poles and structure materials. To establish a relation of mechanical property between paperboards and paper-tubes is an important aspect. The current study is to investigate this relation. Paperboards are built from cellulose fibers jointed by hydrogen bonds and some additional elements like talc. The fibers are distributed randomly on the paperboards. However due to the tension action during fabrication process, more fibers are distributed in machine rolling direction which is defined as machine direction (MD, TD for transverse direction). The material expresses obvious anisotropic property. On the other hand, due to the laminated structure of paper materials, it is possible to generate interlaminar fracture in the usage process, especially in the construction made of paper such as paper tubes. The mechanical property of three kinds of paperboards used for paper-tubes fabrication was investigated included tension, compression and peeling combining with anisotropic property.

These three kinds of paperboards have different mechanical properties but same dimension for paper-tubes fabrications. By this method, the effects of different properties including tension, compression and peeling on mechanical property of paper-tube could be evaluated. A series of paper-tubes with different layers was fabricated and the lateral compression test was carried out and evaluated. The fracture form of paper-tubes and fracture position on paper-tube were discussed together with paperboards. The cause of delamination behavior of laminated paper was analysis based on the detailed observation. The optical observation were employed to evaluate the fracture properties of paper-tubes after lateral compression test. It was found that the initial fracture of paper-tubes occurred inside the paperboards rather than between layers and the peeling property of paperboard has a signification effects on lateral compression property of paper-tubes.
A Conservative Integral for Calculating Intensities of Singularities at 3D Piezoelectric Bonded Joints
Authors: Luangarpa Chonlada , Koguchi Hideo
Published: March 2016

In the present study, a conservative integral based on the Betti reciprocal principle is extended for calculating the intensities of singularities at a vertex of the interface in three-dimensional piezoelectric bonded joints. Eigenanalysis formulated using a three-dimensional finite element method (FEM) is used to calculate the order of stress singularity, angular variables of mechanical displacements, stresses, electric displacements and electric potential. A model with applied both mechanical and electrical loading conditions are considered. In order to investigate the influence of mesh refinement and integral area on the accuracy of the results, models with various element sizes and integral areas are used. The results are compared with those obtained from conventional FEM, in which using extremely refined meshes near the singular point.
Action, Practice and Research in Project Based Learning in an Industrial Engineering and Management Program
Authors: Alves Anabela C. , Leão Celina P.
Published: March 2016

Engineering is a profession that suffers from rapid obsolescence because of constantly new market needs. Therefore, the engineering education curriculum must be adapted to accommodate change and to prepare as well as possible new engineers. To achieve this, Project-Based Learning (PBL) as an active learning methodology, assumes greater importance.

PBL has been implemented for a decade (since 2004/05) in the first semester of the first and fourth year of the Master Degree in Industrial Engineering and Management (IEM) at University of Minho, Portugal, by a team of IEM teachers. This paper describes this last decade of teaching, learning and researching in a PBL environment in this degree. PBL engages students in their own learning. In IEM program, PBL also engaged teachers in improving their teaching methods by questioning continuously these. Throughout ten years, the coordination team of IEM program faced many challenges and brought significant contributions to discussion, researching on how PBL process in IEM could be improved and studying different PBL models for different students’ needs. By following this path, this paper disseminates the practices researched in PBL process of IEM program and the benefits founded by applying this learning methodology through an analysis of the results of this research published in international conferences, journals and books (more than 70 publications). In light of the results achieved, as well as feedback from researchers and students, the authors believe that PBL is one of the best practices for student learning and teacher engagement.
Various Approaches to Numerical Discretization of Thermal Model With Phase Change
Authors: Mauder Tomas , Klimes Lubomir , Charvat Pavel , Stetina Josef
Published: March 2016

Phase change materials are nowadays used in a wide range of technical applications such as energy storage, building temperature comfort, food-freezing, etc. The accurate modelling of this process is important for the performance and usability of many technologies. Analytical solutions can be used only for simple heat transfer problems which make the numerical methods the only possible way how to deal with complex multidimensional cases. This paper deals with the comparison of commonly used numerical schemes for heat diffusion with phase change and its parallel computation possibilities.
Research on Residual Strength of Corroded Tubing of Gas Well With Sustained Casing Pressure
Authors: Sun Li , Fan Jianchun , Meng Xing , Zhang Ximing , Sun Yuting , Liu Di , Yang Zhou
Published: March 2016

Corrosion and sustained casing pressure have serious threats to the integrity of tubing of gas well. Researching the residual strength of corroded tubing has great significance to ensure the safety of gas well. The finite element method was used to study the relationships between residual strength and corrosion defects size, internal pressure, external pressure, axial load. The results show that, for tubing with uniform corrosion, the defect depth, internal pressure and external pressure have greater impacts on the von Mises equivalent stress of tubing, and the defect width and defect length have little effects on it. For tubing with pitting corrosion, the defect depth, internal pressure and external pressure have greater impacts on the von Mises equivalent stress of tubing, while the defect radius has little effect on it. These simulation data were fitted into the functions of residual strength of corroded tubing according to different corrosion morphology types. Both of the verifications of the fitting results show that most of the error between the original calculation data and the fitting calculation data is less than 4%. The fitting formulas can be used conveniently to evaluate the safety of the tubing of gas well with sustained casing pressure.
Fuzzy Rule Based Modeling for Surface Roughness in Machining of Titanium Alloy Using Nano Coated Carbide Inserts
Authors: Nithyanandam J. , Palanikumar K. , Das Sushil Lal
Published: March 2016

Titanium and its alloys are used in many industrial and engineering applications because of their good properties, such as high strength to weight ratio, excellent fracture and corrosion resistance. The major application of titanium has been in the aerospace industry. When turning of titanium alloys with conventional tools, the tool wear rate increases, because of high chemical reactivity and strong adhesion between the tool and work piece materials. The nano coated carbide cutting tool is used for the turning experiment. The cutting parameter for the experimental works are cutting speed, feed rate, nose radius, and depth of cut. Fuzzy logic modeling is used for the prediction of surface roughness in machining of titanium alloy. From the results, the Fuzzy logic model is the best suited method for modeling the turning parameters of titanium alloy by using Nanocoated carbide tools.
Theoretical and Experimental Estimation of Inter-Segmental Clothing Ventilation and Impact on Human Segmental Heat Losses
Authors: Ismail Nagham Bilal , Ghaddar Nesreen , Ghali Kamel
Published: March 2016

Air exchange between a specific garment and the environment could occur 1) through the fabric with the environment, 2) through garment apertures with the environment, and 3) between local body parts’ microclimates. The first mechanism is related to the fabric properties and the flow characteristics around the human body. The second mechanism is induced by buoyancy and pressure alteration due to external wind. The third mechanism named inter-segmental ventilation occurs between different clothing sections caused by position of apertures, relative wind, fabric permeability and microclimate size of connected clothed segments. The objective of this work is to develop a simplified accurate model that solves coupled momentum, mass and heat balances including buoyancy for the connected clothed upper human body to predict inter-segmental ventilation and assess its impact on the air flow characteristics in the microclimate layer and on local ventilation rates. This model is coupled to the bioheat model to predict the effect of the inter-segmental ventilation on the heat losses from the body and on bringing the thermal comfort. The model is validated by performing an improved experimental method on a thermal manikin using the tracer gas method at different wind speeds for permeable clothing.
Thermal Performance of a Borehole Heat Exchanger Located in Guayaquil-Ecuador Using Novel Heat Transfer Fluids
Authors: Soriano Guillermo , Siguenza Diego
Published: March 2016

An analysis of thermal performance of a vertical Borehole Heat Exchanger (BHE) from a close loop Ground Source Heat Pump (GSHP) located in Guayaquil-Ecuador is presented. The project aims to assess the influence of using novels heat transfer fluids such as nanofluids, slurries with microencapsulated phase change materials and a mixture of both. The BHEs sensitive evaluation is performed by a mathematical model in a finite element analysis by using computational tools; where, the piping array is studied in one dimension scenario meanwhile its surroundings grout and ground volumes are presented as a three dimensional scheme. Therefore, an optimized model design can be achieved which would allow to study the feasibility of GSHP in buildings and industries in Guayaquil-Ecuador.
Energy Conversion Analysis of a Novel Solar Thermochemical System Coupled With Fuel Cells
Authors: Vinck Ian , Ozalp Nesrin
Published: March 2016

Fossil fuels have been the main supply of power generation for use in manufacturing, transportation, residential and commercial sectors. However, environmentally adverse effects of fossil fuel conversion systems combined with pending shortage raise major concerns. As a promising approach to tackle these challenges, this paper presents a novel energy conversion system comprising of a solar thermal reactor coupled with hydrogen fuel cell and carbon fuel cell for electricity generation. The system uses concentrated solar energy for high temperature heat which upgrades the calorific value of the feedstock by 8%. The paper describes the components and characteristics of the proposed concept and models the energy flow of this system. A comparison based on unit mass feedstock supply is made with conventional Brayton cycles for electricity production. The results show that the extent of acetylene byproduct conversion in the solar reactor is of crucial importance to ensure competitiveness. Depending on the fuel cells efficiency and even more on the extent of byproduct formation, the results show that the overall chemical-to-electrical efficiency of this combined system ranges from 35 to 58%.
Coordinating College-Wide Instructional Change Through Faculty Communities
Authors: Herman Geoffrey L. , Hahn Laura , West Matthew
Published: March 2016

In February 2012, the College of Engineering created the Strategic Instructional Initiatives Program (SIIP) to transform and revitalize the core engineering courses at the University of Illinois at Urbana-Champaign. As SIIP has evolved, we have learned that in order to achieve these goals, we must first focus on creating collaborative teaching cultures. This effort has sparked the rapid spread of Research-Based Instructional Strategies across the college and created a thriving community of faculty invested in improving undergraduate instruction. In this paper, we describe the current policies and procedures that we use to direct SIIP. In particular, we will focus on the structure of the leadership team and how we have fostered deep collaborations among faculty developers, education researchers, and engineering faculty. We conclude by presenting an evaluation of the program.
Long Term Simulation of Horizontal Ground Heat Exchanger for Ground Source Heat Pump
Authors: Kayaci Nurullah , Demir Hakan , Atayılmaz Ş. Özgür , Ağra Özden
Published: March 2016

The earth is an energy resource which has more suitable and stable temperatures than air. Ground Source Heat Pumps (GSHPs) were developed to use ground energy for residential heating. The most important part of a GSHP is the Ground Heat Exchanger (GHE) that consists of pipes buried in the soil and is used for transferring heat between the soil and the heat exchanger of the GSHP. Soil composition, density, moisture and burial depth of pipes affect the size of a GHE. There are plenty of works on ground source heat pumps and ground heat exchangers in the literature. Most of the works on ground heat exchangers are based on the heat transfer in the soil and temperature distribution around the coil. Some of the works for thermo-economic optimization of thermal systems are based on thermodynamic cycles. GHEs is commonly sized according to short time (one year or less) simulation algorithms. Variation of soil temperature in long time period is more important and, therefore, long term simulation is required to be assure the performance of the GSHP system. In this study, long time (10 years) simulation for parallel pipe GHE of a GSHP system was performed numerically with dynamical boundary conditions. In the numerical study ANSYS CFD package was used. This package uses a technique based on control volume theory to convert the governing equations to algebraic equations so they can be solved numerically. The control volume technique works by performing the integration of the governing equations about each control volume, and then generates discretization of the equations which conserve each quantity based on control volume. Thermal boundary conditions can be defined in four different types in ANSYS Fluent: Constant heat flux, constant temperature, convection-radiation and convection. In this study, periodic variation of air temperature boundary at upper surface condition is applied, the lateral and bottom surface of the solution domain are defined as adiabatic wall type boundary condition; the pipe inner surface is taken as wall with a constant heat flux. In order to provide the periodic variation of air temperature boundary at upper surface condition a User Defined Function (UDF) was written and interpreted in ANSYS Fluent. Likewise, a UDF was also written to give constant heat flux intermittently for the pipe inner surface.

Constant heat flux of 10, 20, 30 W per unit length of pipe used for calculations. Effects of distance between pipes and thermal conductivity on temperature distribution in the soil were investigated. Heat transfer in the soil is time dependent three dimensional heat conduction with dynamical boundary conditions. Temperature distribution in soil were obtained and storage effect of the soil has also been investigated. An optimization methodology based on long term simulation of GHE was suggested.
Interfacial Electrical Shear Stresses Induce Electrohydrodynamic Flows Inside Droplets Actuated by Electrowetting
Authors: Salman W. M. , Ali H. A. , Abdelsalam M. S. , El-Dosoky M. F. F. , Abdelgawad M.
Published: March 2016

In this paper, we numerically investigated electrohydrodynamic flows generated inside droplets undergoing electrowetting. We prove that interfacial shear stresses at the droplet interface are capable, alone, of generating internal electrohydrodynamic flow inside the droplet contrary to previous reports which refer such flows to electrothermal effects. The obtained fluid flow pattern agrees well with previously reported experimental results at the low frequency range of 8∼15 kHz where the effect of all other phenomena (electrothermal, Marangoni, oscillation) are negligible. We studied the effect of applied voltage, frequency, and electrical conductivity of the droplet on the magnitude of the velocity of generated flows. The results obtained will be useful in choosing best conditions to enhance mixing inside droplets while at the same time avoiding temperature rise associated with electrothermal flows which are incompatible with some biological applications.