bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Material Anisotropy on Long Glass Fiber Reinforced Thermoplastics Composite Wheel: Dynamic Impact Simulation
Authors: Wan X. F. , Pan Y. , Liu X. D. , Shan Y. C.
Published: March 2016

As the unsprung components of vehicle, lightweight wheel plays a significance role for handling stability and riding comfort. Besides, the energy saving effect of lightweight design for wheel is 1.2 to 1.3 times as much as that of components without rotating. Therefore, the lightweight design of wheel is an inevitable development tendency in future. For the wheel composed by long-fiber reinforced composites through injection process, the difference of fiber distribution and orientation at various positions leads to anisotropy on the macro performance. This paper explores a new type of high-performance thermoplastic composites (LGFTs) material reinforced by long glass fiber for lightweight wheel design. The dynamic impact simulations on the LGFT wheel with isotropic properties and anisotropic properties are conducted according to the ISO procedure, using the software Moldflow, Digimat, and Abaqus. The comparison of the simulation results demonstrates that the anisotropic properties of material have a significant effect on the impact characteristics of the wheel. The research in this paper is beneficial to improve the accuracy of the impact simulation on LGFT wheel, and also provides foundation for further lightweight design of the wheel.
Adsorption Characteristics of Modified MiL-101(Cr) for Gas (Mainly CH4) Storage Applications
Authors: Teo How Wei Benjamin , Chakraborty Anutosh , Ooi Kim Tiow
Published: March 2016

As promising material for gas storage applications, MIL-101(Cr) can further be modified by doping with alkali metal (Li+, Na+, K+) ions. However, the doping concentration should be optimized below 10% to improve the methane adsorption. This article presents (i) the synthesis of MIL-101 (Cr) Metal Organic Frameworks, (ii) the characterization of the proposed doped adsorbent materials by X-ray Diffraction, Scanning Electron Microscopy, N2 Adsorption, Thermo-Gravimetric Analyzer, and (iii) the measurements of methane uptakes for the temperatures ranging from 125 K to 303 K and pressures up to 10 bar. It is found that the Na+ doped MIL-101(Cr) exhibits CH4 uptake capacity of (i) 295 cm3/cm3 at 10 bar and 160 K and (ii) 95 cm3/cm3 at 10 bar at 298 K. This information is important to design adsorbed natural gas (ANG) storage tank under ANG-LNG (liquefied natural gas) coupling conditions.
Experimental and Computational Studies of Gravity-Driven Dense Granular Flows
Authors: Chilamkurti Yesaswi N. , Gould Richard D.
Published: March 2016

The current paper focusses on the characterization of gravity-driven dry granular flows in cylindrical tubes. With a motive of using dense particulate media as heat transfer fluids (HTF), the study was primarily focused to address the characteristics of flow regimes with a packing fraction of ∼60%. Experiments were conducted to understand the effects of different flow parameters, including: tube radius, tube inclination, tube length and exit diameter. These studies were conducted on two types of spherical particles — glass and ceramic — with mean diameters of 150 μm and 300 μm respectively. The experimental data was correlated with the semi-empirical equation based on Beverloo’s law. In addition, the same flow configuration was studied through three-dimensional computer simulations by implementing the Discrete Element Method for the Lagrangian modelling of particles. A soft-particle formulation was used with Hertz-Mindilin contact models to resolve the interaction forces between particles. The simulation results were used to examine the velocity, shear rate and packing fraction profiles to study the detailed flow dynamics. Curve-fits were developed for the mean velocity profiles which could be used in developing hydrodynamic analogies for granular flows. The current work thus identifies the basic features of gravity driven dense granular flows that could form a basis for defining their rheology.
Photonically Sintered PZT Energy Harvester
Authors: Ouyang Jing , Penmetcha Anirudh R. , Cormier Denis , Borkholder David A.
Published: March 2016

This paper reports an Aerosol-Jet printed micro scale Lead Zirconate Titanate (PZT) energy harvester directly sintered on a low melting point substrate in less than 1 msec using photonic sintering technology. To improve the output signal, d33 piezoelectric mode was employed by patterning silver electrodes as an interdigitated structure on top of a PZT film. The size of the device is 15.5 mm × 13.5 mm × 0.2 mm. Up to 2.4 V was measured at 145 MPa tensile bending stress level in the device after poling at 180 °C for 2 hours with an electric field of 30 kV/cm. Using an oscillating stress (∼2.5 Hz) of approximately 145 MPa, the power as a function of load was determined by connecting the device with various series resistive loads. A maximal power of 0.1 μW was generated when driving into a 10 MΩ load. A PZT energy harvester, for the first time, is demonstrated which has been directly printed and sintered on a low melting temperature flexible substrate without a film transfer processes. This not only dramatically simplifies the fabrication process, but expands the possible substrate materials for PZT energy harvesters.
Synthesis of Concave Helical Compression Springs
Authors: Gandham Naresh Kumar , Zhou Hong
Published: March 2016

Helical compression springs are used to resist compressive forces or store energy in push mode. They are found in many applications that include automotive, aerospace and medical devices. The common configuration of helical compression springs is straight cylindrical shape that has constant coil diameter, constant pitch and constant spring rate. Unlike cylindrical helical compression springs, concave helical compression springs have a larger diameter at each end and a smaller diameter in the middle of the spring. The variable coil diameter enables them to produce desired load deflection characteristics, reduce solid height, buckling and surging, and keep them centered on a larger diameter hole. The unique features of concave helical compression springs also raise their synthesis challenges. In this paper, a method is introduced to synthesize concave helical compression springs. The variable coil diameter of a concave helical compression spring is described by a spline curve. A cylinder with variable diameter is generated by revolving the spline curve on spring axis. The concave helical compression spring is then modeled by wrapping a spring wire on the variable diameter cylinder. The synthesis of a concave helical compression spring is systemized as the optimization of the geometric control parameters of its wrapped spring wire. A synthesis example is presented in the paper to verify the effectiveness and demonstrate the procedure of the introduced method.
Heat-Transfer Analysis of Visco-Elastic Giesekus Fluid in a Duct Between Parallel Plates and in a Straight Pipe of a Circular Cross-Section
Authors: AlMelhi Sara N. , Khezzar Lyes , Alshehhi Mohamed , Filali Abdelkader
Published: March 2016

This work aims to conduct numerical simulation to investigate the convective heat transfer of viscoelastic fluids obeying Giesekus model flowing either along straight pipe of circular cross-section or within the space between parallel plates with constant heat flux thermal boundary condition and neglected viscous dissipation. The numerical technique used is based on finite element software (ANSYS Polyflow 14.0) and the obtained numerical solutions are compared against the analytical solution available in literature. The effect of the rheological parameters on the heat transfer enhancement is discussed.
Profiling a Cylindrical Roller Bearing Oil-Film Thickness Distribution With Ultrasound
Authors: Li Meng , Chen Li , Jing Minqing , Liu Heng , Liu Yi , Qi Shemiao
Published: March 2016

The rollers and raceways in cylindrical roller bearings are separated by an extremely thin lubricant film over a narrow region, which is critical to performance. The ultrasound method has been applied successfully to a range of bearings including journal and ball bearings. But the actual maximum speed that can be measured is limited by the repetition frequency of the ultrasonic pulse. Otherwise, a single measurement point cannot image the thickness distribution of the cylindrical roller bearing. This paper describes the measurement of lubricant-film thickness distribution in a roller bearing by moving the ultrasound transducer. A new ultrasonic pulser-receiver is used to get enough effective measurement points. For a range of loads and speeds, the oil-film thicknesses of four positions along the roller are measured. The influences of the rotating speed and radial load on the film thickness measurement are consistent with the theoretical predictions. The limits of the PRR used in measurements are discussed and the averaging effect of the transducer focal zone size is observed.
Influence of Semi Cone Angle on Performance of a Non-Recessed Hybrid Conical Journal Bearing
Authors: Khakse Prashant G. , Phalle Vikas M. , Mantha S. S.
Published: March 2016

The present paper describes the analytical approach to find the static and dynamic performance characteristics of a newly configured non-recess hole-entry hybrid conical journal bearing, considering the speed effect of journal compensated with capillary restrictors. Capillary restrictors are placed in the holes which are drilled over the periphery of the conical journal bearing. These holes are placed at an angle of 30 degree in the circumferential direction. The modified Reynolds equation which governs the lubricant flow in the clearance space of journal and bearing is solved by using Finite Element Method (FEM). The performance characteristics for the non-recess hole-entry hybrid conical journal bearing have been shown for wide range of restrictor design parameter (C̄s2 = 0.02–0.1) in terms of bearing flow, direct fluid film stiffness and direct fluid film damping coefficient for different semi cone angles γ = 5deg, 10 deg, 20 deg and 30 deg. The results obtained from the simulation indicates that the non-recess hole-entry hybrid conical journal bearing depicts important performance characteristics for bearing flow (Q) and fluid film stiffness which may be useful for bearing designer. However, the non-recess hole-entry hydrostatic conical journal bearing shows desirable performance for fluid film damping coefficient.
Computational Simulation Study on the Viscous Drag of the Automotive Wet Clutch for Prediction and Control
Authors: Sung In-Ha , Ryu Jin Seok
Published: March 2016

The reduction of drag torque is an important issue in terms of improving transmission efficiency. Drag torque in a wet clutch occurs because viscous automatic transmission fluid flow narrow gap between friction plate and separate plate. The main purpose of this study is to observe the effects of the various parameters on the drag torque using finite element simulation.

In this study, the simulation analysis reveals that as the rotational speed increases, the drag torque generally increases to a critical point and then decreases sharply at a high speed regime. Depth of groove on the friction plate plays an important role in controlling drag torque peak. An increase in the depth of groove causes a decrease in shear stress; thus, the drag torque also decreases according to Newton’s law of viscosity.

Also, an observation of the effect of the angle of groove pattern shape shows that the drag torque changes with groove pattern shape. Therefore, the optimum angle of the groove pattern should be determined carefully, considering both the clutch performance and drag reduction.

It is expected that the results from this study can be very useful as a database for clutch design and to predict the drag torque for the initial design with respect to various clutch parameters.
On the Development of a 3D Printer for Combinatorial Structural Composite Research
Authors: Allameh Seyed
Published: March 2016

Bioinspired materials have enabled the fabrication of tough lightweight structures for load- and impact-bearing applications of which an example is fiber-reinforced plastics use in aerospace. If applied to the field of construction, biomimicked composites can save lives, otherwise lost to earthquakes and other disasters that cause collapse of buildings. The main culprit is the low resistance of structures exposed to dynamic shear stresses, typical of earthquakes. Recent work on the application of biomimicry to structural composites has clearly shown the advantage of these materials in resisting dynamic shear. Adding natural or synthetic reinforcement fibers may alleviate the need for conventional steel rebars and make it possible to print buildings by conventional 3D printing technology. The main hurdles are to find the right type of composite that is compatible with 3D printing and the right process for deposition of such material. In the past, combination of carbon fiber, glue and concrete has been demonstrated to enhance the toughness of resulting structural composites. Inspired by the microstructure of oyster and mother of pearl, layering of these materials mitigates the localization of deformation by distributing the imposed displacement over a large area. The intricate structure of these layers, and the minute details of the interfaces are important for affecting good dynamic shear resistance. In nacre, a partial slip of sandwiched layers occurs before it stops and deformation is transferred to the adjacent area. This energy-absorption capability underlies the high-toughness behavior of nacre and similar structures. By mimicking nacre, bone and tooth, it is possible to benefit from their good properties, however, it is important to determine the type of material, layering scheme, geometry, and other factors that affect mechanical properties. A recently-developed medium-sized 3D printer was developed to deposit structural materials. These include cement, plaster, polymer and clay. Combinatorial structural composite research (CSCR) comprising the simultaneous fabrication and characterization of multiple specimens with different microstructures allows fair comparison of mechanical properties of various structural composites. Novel application of deposition techniques to the extrusion of plaster, cement and clay paves the way to layer these materials along with glue and fibers in desired schemes. Use of ANOVA tables in the selection of various types of ceramics, polymers and reinforcement materials for the fabrication of different composites will be discussed. In addition to selection of the type of the materials, deposition schemes such as those of solid and hollow structures, different layer thickness applications, and the effect of timing will be elucidated. Microscopy conducted on the fractured surfaces enables the investigation of the mechanisms of fracture and failure for these CSCR composites. The details of experiments conducted, microscopy performed and the results of mechanical tests will be presented.
Vibration Reduction Using a Nonlinear Attachment Including an Active Damper With Delay
Authors: Bellizzi Sergio , Chung Kwok W.
Published: March 2016

This paper presents the interest of a nonlinear passive absorber coupled to a semi-active damper with delay for vibration isolation of harmonic disturbances. The passive absorber consists of an essentially nonlinear oscillator (nonlinear energy sink [NES]), having the task to transfer the energy from the main structure to the semi-active device. The semi-active device consists of an active viscous damper with semi-active strategy control including delay. A theoretical/numerical analysis based on complexification and averaging methods together with multipe scale method is performed. It is shown that the approach is able to predict the behaviour of the system including time delay. The influence of the time delay on the efficiency of semi-active nonlinear absorber is studied. It is shown that time-delay could be used as a design parameter to improve the control of the vibration of the primary system suppressing strongly modulated regimes through periodic regimes.
Stability Analysis of a Macroscopic Traffic Flow Model for Adaptive Cruise Control Systems
Authors: Porfyri K. N. , Nikolos I. K. , Delis A. I. , Papageorgiou M.
Published: March 2016

Since the early days of traffic engineering, traffic flow stability has attracted a lot of attention, as the frequent occurrence of traffic jams, caused by small perturbations in traffic flow such as a sudden deceleration of a vehicle, deteriorate the performance of traffic flow and the utilization of the available infrastructure. Such traffic jams are usually related to instabilities in traffic flow, resulting in the formation of stop-and-go waves, propagating upstream the traffic flow. Emerging technologies in the field of Vehicle Automation and Communication Systems (VACS), such as Adaptive Cruise Control (ACC) systems, appear to be a remedy to reduce the amplitude or to eliminate the formation of such traffic instabilities. To this end, this work aims to derive a stability threshold of a novel macroscopic model, developed to simulate the flow of ACC-equipped vehicles, and study the impact of such vehicles on the stabilization of the traffic flow, with respect to small perturbations. The adopted macroscopic approach reflecting ACC traffic dynamics is based on the gas-kinetic (GKT) traffic flow model. The analytic results show that ACC vehicles enhance the stabilization of the traffic flow; the instability region is very narrow and by reducing the ACC time-gap setting it moves to higher values of density.
Mechatronics Implementation of Inverse Dynamics-Based Controller for an Off-Road UGV
Authors: Salama Mostafa , Vantsevich Vladimir V.
Published: March 2016

This paper presents a project developed at the University of Alabama at Birmingham (UAB) aimed to design, implement, and test an off-road Unmanned Ground Vehicle (UGV) with individually controlled four drive wheels that operate in stochastic terrain conditions.

An all-wheel drive off-road UGV equipped with individual electric dc motors for each wheel offers tremendous potential to control the torque delivered to each individual wheel in order to maximize UGV slip efficiency by minimizing slip power losses. As previous studies showed, this can be achieved by maintaining all drive wheels slippages the same. Utilizing this approach, an analytical method to control angular velocities of all wheels was developed to provide the same slippages of the four wheels. This model-based method was implemented in an inverse dynamics-based control algorithm of the UGV to overcome stochastic terrain conditions and minimize wheel slip power losses and maintain a given velocity profile.

In this paper, mechanical and electrical components and control algorithm of the UGV are described in order to achieve the objective. Optical encoders built-in each dc motor are used to measure the actual angular velocity of each wheel. A fifth wheel rotary encoder sensor is attached to the chassis to measure the distance travel and estimate the longitudinal velocity of the UGV. In addition, the UGV is equipped with four electric current sensors to measure the current draw from each dc motor at various load conditions. Four motor drivers are used to control the dc motors using National Instruments single-board RIO controller. Moreover, power system diagrams and controller pinout connections are presented in detail and thus explain how all these components are integrated in a mechatronic system.

The inverse dynamics control algorithm is implemented in real-time to control each dc motors individually. The integrated mechatronics system is distinguished by its robustness to stochastic external disturbances as shown in the previous papers. It also shows a promising adaptability to disturbances in wheel load torques and changes in stochastic terrain properties. The proposed approach, modeling and hardware implementation opens up a new way to the optimization and control of both unmanned ground vehicle dynamics and vehicle energy efficiency by optimizing and controlling individual power distribution to the drive wheels.
Design and Numerical Analysis of a Vehicle Armour Against Bullets and Shaped Charges
Authors: Kayki M. Ömer , Kayaci Nurullah , Özbeyaz Kerim
Published: March 2016

Armored vehicles are used to carry soldiers and machinery in combat environment in safety. As a result of the experience of a military force involved in the missions in combat areas, armoring of military-vehicle should be durable against bullet impacts and shaped charge explosions. These vehicles should provide required protection of soldiers and equipment against penetration and explosion and also have good mobility (moveable capability). In order to achieve this, the vehicle must be lightweight. The most suitable material should be selected and the most suitable geometry should be designed to achieve this goal. In this study; different material combinations and different geometries are simulated using the finite element method and smooth particle hydrodynamics. Different caliber bullets are impacted into armor and their penetration affects are observed. Shaped charge explosive also used. As a result of this simulation, the material combinations are optimized to achieve the best armor.
Design and Characteristics of the Micro-Hydrokinetic Turbine System
Authors: Riglin Jacob , Daskiran Cosan , Oblas Nick , Schleicher W. Chris , Oztekin Alparslan
Published: March 2016

Small, hydrokinetic systems generating between 0.5 and 10 kW of power allow for the potential of portable power generation. An optimized propeller turbine approximately 0.6826 m in diameter and a diffuser with an area ratio of 1.31 were used to produce a prototype for preliminary testing. The optimized diffuser augmented hydrokinetic turbine was investigated numerically to predict power and thrust curves for comparison during experimental testing. A gear box with a 10:1 gear ratio was selected for converting torque to angular velocity. A DC permanent magnet generator was selected for mechanical-electrical power conversion. At the ideal generator operating conditions consisting of a shaft rotation rate of 1150 RPM, a voltage of 48 V, and current of approximately 8 A, 375 W of power may be generated at a river flow speed of 1.5 m/s. Numerical predictions coupled with component efficiencies yield a system efficiency of approximately 0.61 before DC/DC conversion and 0.52 after DC/DC conversion.
The Folding Course for the Tensegrity Basic Unit
Authors: Liu Heping , Li Xu , Cheng Jianjun , Yuan Li , Yuan Ye , Li Quanhe , Luo Ani
Published: March 2016

The tensegrity structure with characteristics of light weight and little compression volume is a hot spot for research in architecture and spaceflight. The tensegrity basic unit is the foundation of other tensegrity structure. The tensegrity basic unit is analyzed in the text in order to provide methods for research on other tensegrity structure. At first, node coordinates of the nodes and connectivity matrix are adopted to set up the math expressions of vectors of all the bars and strings. After structural characteristics of the tensegrity basic unit are analyzed, the two folding methods are presented. The driving method where lengths of all the bars are constant and the level strings are shortened to fold the structure is analyzed in detail. Changes of length, velocity and acceleration of every member are researched in the course of folding the structure. Geometrical relationships among the members are adopted to set up the equilibrium equations of the nodes. With the equations, changes for the internal forces of all members are computed in the folding course of the structure. Applications of the folding methods to a tensegrity mast are researched. Through analysis in the text, methods for setting up math model of the tensegrity basic unit and folding it are obtained. The methods obtained in the text can be applied as a reference to research on other tensegrity structures.
Fast CT-FFR Analysis Method for the Coronary Artery Based on 4D-CT Image Analysis and Structural and Fluid Analysis
Authors: Kato Mitsuaki , Hirohata Kenji , Kano Akira , Higashi Shinya , Goryu Akihiro , Hongo Takuya , Kaminaga Shigeo , Fujisawa Yasuko
Published: March 2016

Non invasive fractional flow reserve derived from CT coronary angiography (CT-FFR) has to date been typically performed using the principles of computational fluid analysis in which a lumped parameter coronary vascular bed model is assigned to represent the impedance of the downstream coronary vascular networks absent in the computational domain for each coronary outlet. This approach may have a number of limitations. It may not account for the impact of the myocardial contraction and relaxation during the cardiac cycle, patient-specific boundary conditions for coronary artery outlets and vessel stiffness. We have developed a novel approach based on 4D-CT image tracking (registration) and structural and fluid analysis based on one dimensional mechanical model, to address these issues. In our approach, we analyzed the deformation variation of vessels and the volume variation of vessels to better define boundary conditions and stiffness of vessels. We focused on the blood flow and vessel deformation of coronary arteries and aorta near coronary arteries in the diastolic cardiac phase from 70% to 100 %. The blood flow variation of coronary arteries relates to the deformation of vessels, such as expansion and contraction of the cross-sectional area, during this period where resistance is stable, pressure loss is approximately proportional to flow. We used a statistical estimation method based on a hierarchical Bayes model to integrate 4D-CT measurements and structural and fluid analysis data. Under these analysis conditions, we performed structural and fluid analysis to determine pressure, flow rate and CT-FFR. Furthermore, the reduced-order model based on fluid analysis was studied in order to shorten the computational time for 4D-CT-FFR analysis. The consistency of this method has been verified by a comparison of 4D-CT-FFR analysis results derived from five clinical 4D-CT datasets with invasive measurements of FFR. Additionally, phantom experiments of flexible tubes with and without stenosis using pulsating pumps, flow sensors and pressure sensors were performed. Our results show that the proposed 4D-CT-FFR analysis method has the potential to accurately estimate the effect of coronary artery stenosis on blood flow.
Performance Study on Vortex Tube Air Intake Filter in Gas Turbine
Authors: Sun Tao , Sun Peng , Sun Lanxin , Luan Yigang , Zhang Mingfei
Published: March 2016

A new vortex tube structure with small length-diameter ratio, low resistance coefficient and high efficiency based on the basic structure and principle of the helicopter vortex tube is designed by numerical computation and experimental study in this paper. The average value of error between the resistance experiment and numerical simulation is within 5.6%. This indicates the resistance mathematic model can estimate the resistance of the vortex tube very well. It provided a feasible way for the optimal design of the vortex tube.
Prediction of Rice Husk Particulate-Filled Polymer Composite Properties Using a Representative Volume Element (RVE) Model
Authors: Pochanard Pandhita , Saigal Anil
Published: March 2016

In this study, a numerical representative volume element (RVE) model was used to predict the mechanical properties of a Rice Husk Particulate (RHP)-Epoxy composite for use as an alternative material in non-critical applications. Seven different analytical models Counto, Ishai-Cohen, Halpin-Tsai, Nielsen, Nicolais, Modified Nicolais and Pukanszky were used as comparison tools for the numerical model.

The mechanical properties estimated for 0%, 10% and 30% RHP-Epoxy composites using the numerical and analytical models are in general agreement with each other. Using the analytical models, it was calculated that an increase in volume percentage of RHP to 30% led to continual reduction in elastic Young’s modulus and ultimate tensile strength of the composite. The numerical RVE models also predicted a similar trend between filler volume percentage and material properties.

Overall, the results of this study suggest that RHP can be used to reduce the composite raw material costs by replacing the more expensive polymer content with agricultural waste products with limited compromise to the composite’s mechanical properties.
Usage of Revision Control Tools in Capstone Senior Design Courses
Authors: Meyers Bryan T. , Hensel Edward , DeBartolo Elizabeth
Published: March 2016

The capstone project serves as the culminating experience of most engineering programs. Collaborative design and documentation tools are an integral component of a modern product design and development environment. The Engineering Design Guide and Environment (EDGE), is a web-based system which provides engineers with tools for collaboration on multidisciplinary projects. The EDGE system includes version-controlled repositories for project documentation and design files. By examining the history of changes to these repositories, it is possible to view the usage trends of the system and their relationship to curriculum structure. This paper explores these usage trends with respect to the transition from a quarter-based to a semester-based calendar, the cycle of project deliverables within an academic term, and the transition from a one-day-per-week meeting pattern to a two-day-per-week meeting pattern.
Evaluation of Rotational Speed Control System for Water Driven Spindle With Disturbance Observer
Authors: Hayashi Akio , Nakao Yohichi
Published: March 2016

In ultra-precision machining to produce various precision products such as lenses or mirrors, the single-point diamond cutting is mainly carried out to achieve the high accuracy and high quality machined surfaces. Thus, the precise rotation accuracy is required to the spindle of the ultra-precision machining tool.

The water driven spindle had been developed for the precision machining tool spindle. This spindle is driven by the torque of water flow power. Then, the rotational speed can be controlled by supplied flow rate of water. However, the rotational spindle speed during cutting operation is changed due to the influence of the cutting forces during the machining processes. The change in the rotational speed causes the change in the cutting speed, as a result, it degrades the machined surface quality as well.

In order to reveal and reduce the influence of this phenomenon, the mathematical model of the rotational speed control system for water driven spindle was derived. This rotational speed control system consists of the water driven spindle and the flow control valve. From the simulation results using a derived transfer function of the rotational speed control system, it is clarified that the rotational speed changes depending on the external load torque.

Then, based on the mathematical model, the feedback rotational speed control system with a conventional P-I controller is designed. The effectiveness of the proposed feedback control system is verified by the turning tests. Furthermore, a disturbance observer to minimize the influence of cutting forces on the rotational speed was added to the feedback control system.

As a result, this paper shows the performance of the rotational speed control system.
The Simulation of Natural Ventilation of Buildings With Different Location of Windows/Openings
Authors: Idris A. , Huynh B. P. , Abdullah Z.
Published: March 2016

Ventilation is a process of changing air in an enclosed space. Air should continuously be withdrawn and replaced by fresh air from a clean external source to maintain internal good air quality, which may referred to air quality within and around the building structures. In natural ventilation the air flow is due through cracks in the building envelope or purposely installed openings. Its can save significant amount of fossil fuel based energy by reducing the needs for mechanical ventilation and air conditioning. Numerical predictions of air velocities and the flow patterns inside the building are determined. To achieve optimum efficiency of natural ventilation, the building design should start from the climatic conditions and orography of the construction to ensure the building permeability to the outside airflow to absorb heat from indoors to reduce temperatures. Effective ventilation in a building will affects the occupant health and productivity. In this work, computational simulation is performed on a real-sized box-room with dimensions 5 m × 5 m × 5 m. Single-sided ventilation is considered whereby openings are located only on the same wall. Two opening of the total area 4 m2 are differently arranged, resulting in 16 configurations to be investigated. A logarithmic wind profile upwind of the building is employed. A commercial Computational Fluid Dynamics (CFD) software package CFD-ACE of ESI group is used. A Reynolds Average Navier Stokes (RANS) turbulence model & LES turbulence model are used to predict the air’s flow rate and air flow pattern. The governing equations for large eddy motion were obtained by filtering the Navier-Stokes and continuity equations. The computational domain was constructed had a height of 4H, width of 9H and length of 13H (H=5m), sufficiently large to avoid disturbance of air flow around the building. From the overall results, the lowest and the highest ventilation rates were obtained with windward opening and leeward opening respectively. The location and arrangement of opening affects ventilation and air flow pattern.
Methotrexate Loaded Magnetic Nanoparticles as a Targeted Drug Delivery Device
Authors: Saeednia L. , Asmatulu R.
Published: March 2016

Targeted drug delivery systems have been shown to be promising alternative for the conventional drug delivery methods. Among numerous nanocarriers developed for therapeutic applications, iron oxide magnetic nanoparticles have attracted considerable attention. Fe3O4 (magnetite) is one of the most commonly used iron oxide in biomedical applications due to its biocompatibility and can be easily produced in research and industrial laboratories. The core/shell structure of magnetic nanoparticles allows the surface coating to avoid their agglomeration. Moreover, coating of Fe3O4 nanoparticles provide functional groups and consequently make the bioconjugation to the therapeutic agents. Coating magnetic nanoparticles with a biopolymer will also increase biocompatibility. Coating magnetic nanoparticles with a biopolymer will also increase biocompatibility. Chitosan can easily conjugate to the surface of magnetic nanoparticles and provide amine and hydroxyl groups for the further conjugation of the therapeutic drug. In this study, Fe3O4 magnetic nanoparticles were fabricated and were coated with chitosan via in-situ method. Prepared chitosan coated magnetic nanoparticles then were loaded with methotrexate (anti-cancer drug) through adsorption. The size and morphology of synthesized magnetic nanoparticles were evaluated using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The chemical structure of bare and chitosan coated magnetic nanoparticles was analyzed by Fourier Transforms Infrared (FTIR). Methotrexate loading efficiency of chitosan coated nanoparticles was also evaluated. Cytotoxicity of nanoparticles was also studied in-vitro. The results confirmed the surface coating with chitosan and methotrexate loading. The synthesize chitosan coated magnetic nanoparticles showed promising application for cancer treatment.
Control of Heat Integrated Distillation Employed by Cryogenic Air Separation Using Decentralized Simple PID Controllers
Authors: Elzouka Mahmoud , Elgohary Mohammed , Attia Abdelhamid
Published: March 2016

Coupling cryogenic air separation plant to industrial processes imposes demand change on the air separation process. Therefore, control of cryogenic air separation plant is a must for stable operation. In this research, we introduce a control scheme for heat integrated distillation which is the main process of cryogenic air separation. The control is achieved via decentralized PID controllers, and its performance is investigated using numerical simulation. Sizing of distillation columns, control valves and heat exchanger were undertaken to simulate industrial air separation plant. In order to verify control system performance, five different control scenarios were studied, including switching between full load to part load, and switching between full production of oxygen to full production of nitrogen, which has not been reported in literature. The simulation results show satisfactory performance of control system facing the disturbing scenarios. However, in severe transition cases (i.e. transition from full liquid nitrogen to full liquid oxygen production), liquid level in the low pressure column base increased excessively and approached safe operating limits. This side effect requires care in controllers tuning, or even introducing level interlocks.
Modeling of Crack Propagation Behavior of High Density Polyethylene by Using Crack Layer Theory: Parametric Study
Authors: Wee Jung-Wook , Choi Byoung-Ho
Published: March 2016

Creep and fatigue slow crack propagation of engineering thermoplastics display continuous or discontinuous manner depending on the test condition. It could be simulated accurately by use of crack layer theory with theoretical backgrounds. But many input parameters complexify the use of CL theory. Thus the investigation on the effect of material parameters on the CL growth is necessary for the comprehensive understanding. In this paper, a parametric study of CL growth simulation of single edge notched tension specimen in creep condition was performed. Several material parameters were varied so that the effect of input parameters on the CL growth behavior could be understood. Total lifetime is used to figure out the effect of the parameters quantitatively. This study would be beneficial to understand the effect of material parameters on the slow crack growth behavior of high density polyethylene.
Asymptotic Effective Piezoelectric Coefficient Solution of Piezoresponse Force Microscopy for a Transversely Isotropic Piezoelectric Film
Authors: Wang J. H. , Chen C. Q.
Published: March 2016

Based on the coupled theory, a simple explicit solution of piezoresponse force microscopy (PFM) in determining the effective piezoelectric coefficient for an ultra-thin transversely isotropic piezoelectric film bonded to a rigid conducting substrate is obtained, using the Taylor expansion and homogeneous assumption. And it is found to be exactly the same as the well-known result for the case of piezoelectric thin film clamped between flat rigid electrodes for homogeneous external electric field. The electric charge and the distance from the image charge model are also derived and the influences of the film thickness and substrate permittivity on the effective piezoelectric coefficient are then discussed. The obtained results can be used to quantitatively interpret the PFM signals and directly detect the piezoelectric constant through PFM for an ultra-thin film or supply important information for constructing a reliable formula to describe the thickness effect.
Improving Dynamic Fault Tree Method for Complex System Reliability Analysis: Case Study of a Wind Turbine
Authors: Asghari Jafar , Pourgol Mohammad Mohammad , Salehpour Oskouyi Farzin
Published: March 2016

Fault Tree Analysis (FTA) is one of the most developed techniques in reliability studies; however static analysis is not able to encompass the dynamic behavior of complex systems. To overcome this problem, Dynamic Fault Tree (DFT) analysis is suggested in recent researches. The main motivation of this study is a comparative study on differences between Static Fault Tree (SFT) and DFT models of a typical mechanical system (case study of a wind turbine). Also, this paper is aimed to interpretation of the results and sufficiency analysis of SFT to model this system. This study, first presents a SFT analysis for a wind turbine system. Then, DFT is developed for the system. Monte Carlo simulation based method is applied for its analysis. The comparison showed that the DFT method presents more useful and realistic model of a wind turbine system. The proposed method improved the analysis through modification of dynamic gates.
An Axiomatic Design Interpretation on the Use of Response Surface Methodology to Solve Coupled Designs
Authors: Fradinho João , Mourão António , Gabriel-Santos António , Cavique Miguel , Gonçalves-Coelho António
Published: March 2016

The most important design decisions are made in the outset of the designing process, when the knowledge about the final design solution is usually scarce and therefore uncertainty is high. According to the independence axiom of Axiomatic Design (AD), design solutions are classified in the following three basic types: uncoupled, decoupled and coupled, the former being the best type and the latter the poorest. As a rule, coupled designs should be avoided, not only because they infringe the independence axiom but also because their information content is hard to compute. Nonetheless, we argue that the occurrence of coupled solutions is noteworthy in general design, although we recognize that they are questionable and that many times they could be easily avoided. Our motivation is to contribute for changing the current state of affairs by showing how to use the minimum information content axiom to make early decisions in the development of coupled designs. One of the general engineering approaches to deal with multiple-FR, multiple-DP designs is the Response Surface Methodology (RSM). We will show in our paper how RSM can be used to deal with coupled designs as if they were uncoupled. The conclusion is that one can graphically compute the information content of coupled designs with two DPs and an arbitrary number of FRs by using multiple RSM. This means that RSM can be interpreted at the light of Axiomatic Design, and embodies an appropriate approach to support decision-making in the case of coupled designs.
Application of Anytime Control to an Inherently Unstable Physical System
Authors: Maxwell Wayne , Ferri Al , Ferri Bonnie
Published: March 2016

This paper extends the use of closed-loop anytime control to systems that are inherently unstable in the open-loop. Previous work has shown that anytime control is very effective in compensating for occasional missed deadlines in the computer processor. When misses occur, the control law is truncated or partially executed. However, the previous work assumed that the open-loop system was stable. In this paper, the anytime strategy is applied to an inverted pendulum system. An LQR controller with estimated state feedback is designed and decomposed into two stages. Both stages are implemented most of the time, but in a small percentage of time, only the first stage is applied, with the resulting closed-loop system being unstable for short periods of time. The statistical performance of the closed-loop system is studied using Monte-Carlo simulations. It is seen that, on average, the closed-loop performance is very close to that of the full-order controller as long as the miss rate is relatively small. However, the variance of the response shows much higher dependence on the miss rate, suggesting that the response becomes more unpredictable. At a critical value of miss rate, the closed-loop system is unstable. The critical miss rate found through simulation is seen to correlate well with the results of a deterministic stability analysis. The statistics on the settling time are also studied, and shown to grow longer as the miss rate increases. The transient behavior of the system is studied for a range of initial conditions.
On the Laws and Theories of Sliding Friction
Authors: Saka Nannaji
Published: March 2016

The many seminal contributions made by Professor Nam P. Suh to the theories of wear, such as the delamination wear and the solution wear, are well known. The contributions made by him and his associates to the theories of friction, however, are less known; but they are equally significant. In this article, I first briefly survey, to provide an historical context, the laws and theories of sliding friction as proposed over the past centuries and decades. Then the contributions of Prof. Suh and his associates in recent decades are reviewed. Specifically, the role of wear particles in the frictional phenomena of dry and boundary-lubricated sliding is examined. A novel concept of undulating, or patterned, surfaces has been advanced to minimize friction in both dry and boundary-lubricated sliding. The undulating surfaces trap wear debris and thus minimize plowing friction in dry sliding, above the transition temperature in boundary-lubricated sliding, and even in hydrodynamic bearings during start/stop operations. The concept is especially appropriate for heavily loaded tribological systems with tighter clearances in which the likelihood of seizure is imminent.
Experimental Analysis of Diesel Engine Exhaust Gas Coupled With Water Desalination for Improved Potable Water Production
Authors: Panchal Hitesh , Patel Vipul , Prajapati Vinod , Patel Dharmendra , Patel Haresh , Patel Sachin
Published: March 2016

Exhaust gas temperature of diesel engine is higher compared with a petrol engine and also creates higher pollution in the environment. Exhaust gas recirculation system and many other systems have used for reuse of exhaust gas to improve the performance of diesel engine, but the use of diesel engine for production of potable water production is still unattended by the researchers. The main aim of this research work is to use the waste heat of exhaust gas for potable water production from the low capacity desalination system integrated with evaporator and condenser unit. In this work, single pass evaporator and water cooled condenser used for evaporation and condensation of saline water were designed and fabricated by locally available materials. The experiments were performed on a 10 HP Diesel engine with varying the load to get potable water. It has found that, 4.2 Liter/hr of potable water is obtained from the exhaust gas without varying the performance of the engine. Also, it has found that, temperature of saline water is heated more than 70 degrees Celsius in the condenser unit.
Enhancement of Heat Transfer Performance in Nuclear Fuel Rod Using Nanofluids and Surface Roughness Technique
Authors: Liu Kang , Paul Titan C. , Carrilho Leo A. , Khan Jamil A.
Published: March 2016

The experimental investigations were carried out of a pressurized water nuclear reactor (PWR) with enhanced surface using different concentration (0.5 and 2.0 vol%) of ZnO/DI-water based nanofluids as a coolant. The experimental setup consisted of a flow loop with a nuclear fuel rod section that was heated by electrical current. The fuel rod surfaces were termed as two-dimensional surface roughness (square transverse ribbed surface) and three-dimensional surface roughness (diamond shaped blocks). The variation in temperature of nuclear fuel rod was measured along the length of a specified section. Heat transfer coefficient was calculated by measuring heat flux and temperature differences between surface and bulk fluid. The experimental results of nanofluids were compared with the coolant as a DI-water data. The maximum heat transfer coefficient enhancement was achieved 33% at Re = 1.15 × 105 for fuel rod with three-dimensional surface roughness using 2.0 vol% nanofluids compared to DI-water.