bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano Investigation of Cracks in Tungsten-Doped Diamond-Like Carbon (DLC) Coatings
Authors: Abou-Hanna Jeries , Carlson John , Lozano Jose´
Published: April 2008

Tungsten-doped diamond-like carbon (DLC) coatings have been magnetron sputtered onto 52100 steel blocks with chromium and chromium / tungsten carbide compound interlayers. The surface finish (Ra) of the substrate before deposition was 0.102 to 0.203 μm. The effect on the growth of the film of this substrate finish as well as surface contaminants is investigated using SEM and TEM. In areas of greatest substrate roughness, the coatings exhibited cracks from near the columnar structured chromium interlayer through the coating thickness. STEM EDS analysis shows chemistry variations at the interlayers to be minimal. In the areas with surface contaminants, cracks are observed in the film at an approximately 45° angle to the substrate.
Floor Reliability With Respect to “Slip and Fall”
Authors: Barnett Ralph Lipsey , Poczynok Peter Joseph
Published: April 2008

For a given community of walkers and a specific type of ambulation, force-plate studies have established the required level of horizontal resistance for stable locomotion. This stochastic floor loading is resisted by friction forces which must be great enough to prevent slipping. A statistical characterization of frictional resistance has recently been developed using extreme value statistics. Reliability theory provides a method for combining the floor loading and friction resistance which, for the first time, enables one to determine in a rational manner the probability of slipping. This paper presents a formula describing the “slip and fall” reliability of a floor/footwear couple.
The Effect of Electrode Shape and Force on the Contact Resistance of Spot Welded Joints
Authors: Esme Ugur , Cakmak AyCa
Published: April 2008

Contact resistance is an important parameter in the control of electrical spot welding. Here, a large current is passed through two water cooled copper electrodes which also clamp the sheets to be welded [1]. The contact resistance should not be too high, otherwise too much current is diverted to previously formed, neighbouring spot welds, and can make nugget formation difficult to control in the early part of the welding cycle. However, if it is too low, nugget formation is not completed at the interface. Therefore, the parameters that affect the contact resistance must be known and it must be compatible with the welding conditions [2]. The present paper reports the relationship between contact resistance, force, and electrode shape. A series of experiments were carried out using aluminium and steel specimens with different thicknesses to measure the faying surface and electrode-workpiece contact resistances.
Relationship Between Vibrations and Mechanical Seal Failures in Centrifugal Pumps
Authors: Stefanko David B. , Leishear Robert A.
Published: April 2008

A reduction of radial vibrations in mechanical seals increases the life of the seals in centrifugal pumps. Mechanical seals consist of two smooth seal faces. One face is stationary with respect to the pump. The other rotates. Between the faces a fluid film evaporates as the fluid moves radially. Ideally, the film evaporates as it reaches the outer surface of the seal faces, thereby preventing leakage from the pump and effectively lubricating the two surfaces. Relative vibrations between the two surfaces affect the fluid film, damage the faces, and decrease the life of the seals. In a series of industrial applications, different techniques were used to minimize vibration, and the life of the seals was shown to significantly increase. The operating speed was controlled in one case, the bearing design was replaced in another case, and the stiffness of the pump was altered in still another case. The common corrective action in each case was a reduction in vibration.
Investigation of High Temperature Mechanical Properties for Improved Finite Element Analysis Simulations of Forged Railroad Wheels
Authors: Dedmon Steven , Pilch James , Lonsdale Cameron
Published: April 2008

Finite element analysis (FEA) programs depend on accurate evaluation of mechanical and physical properties for determination of thermo-mechanical characteristics of wheel designs. For wheel residual stress analyses, both property types are equally important. Also important is knowledge of the anisotropy of properties in a design. For this paper, the authors tested AAR M107/M208 Class “C” steel ingot material and an as-forged (but untreated) wheel. The information presented includes elevated temperature mechanical properties of ingot material taken in circumferential, radial and axial orientations at two depth positions. High temperature mechanical property data (not currently found in the literature beyond 1800F) is also included for the ingot steel. Untreated as-forged AAR Class “C” material mechanical properties were evaluated at temperatures up to 2000F, and at the rim, plate and hub locations. High temperature mechanical property data for heat treated micro-alloy AAR Class “C” wheels are also presented.
Heat Transfer in an Annular Fin With Coordinate Dependent Thermal Conductivity
Authors: Aziz A.
Published: April 2008

Some new exact analytical solutions are reported for heat transfer in an annular fin of rectangular profile with coordinate dependent thermal conductivity. A power law type of dependence on radial coordinate is assumed. The analysis assumes a constant base temperature and an insulated tip. Solutions are developed for the temperature distribution, the heat transfer rate, the fin efficiency, and the fin effectiveness. These solutions appear in terms of Airy wave functions or modified Bessel functions or hyperbolic functions or power functions depending on the exponent of the power law variation. Numerical results are presented to illustrate the effect of coordinate dependent thermal conductivity on the thermal performance of the fin. Comparison of exact and results based on the average thermal conductivity model reveals that the latter is in error by as much as 56 percent in a specific situation. The fin model used here is applicable to some contemporary engineering applications where fins made of heterogeneous materials are used. The analysis can be extended to other profile shapes and different thermal boundary conditions.
Simplified Heat Transfer Analysis in Metal Foam With Low-Conductivity Fluid
Authors: Dukhan Nihad , Pico´n-Feliciano Rube´n
Published: April 2008

The use of open-cell metal foam in contemporary technologies is increasing rapidly. Certain simplifying assumptions for the combined conduction/convection heat transfer analysis in metal foam have not been exploited. Solving the complete, and coupled, fluid flow and heat transfer governing equations numerically is time consuming. A simplified analytical model for the heat transfer in open-cell metal foam cooled by a low-conductivity fluid is presented. The model assumes local thermal equilibrium between the solid and fluid phases in the foam, and neglects the conduction in the fluid. The local thermal equilibrium assumption is supported by previous studies performed by other workers. The velocity profile in the foam is taken as non-Darcean slug flow. An approximate solution for the temperature profile in the foam is obtained using a similarity transform. The solution for the temperature profile is represented by the error function, which decays in what looks like an exponential fashion as the distance from the heat base increases. The model along with the simplifying assumptions were verified by direct experiment using air and two aluminum foam samples heated from below, for a range of Reynolds numbers. Each foam sample was 5.08 cm-thick in the flow direction. One sample had a pore density of ten pores per inch while the other had twenty pores per inch. Very good agreement was found between the analytical and the experimental results for a considerable range of Reynolds number, with the agreement being generally better for higher Reynolds numbers, and for foam with higher surface area density.
A Nonlinear Reduced Order Model for Estimation and Control of Vacuum Arc Remelting of Metal Alloys
Authors: Beaman Joseph J. , Williamson Rodney L. , Melgaard David K. , Hamel Jon
Published: April 2008

Vacuum arc remelting (VAR) is an industrial metallurgical process widely used throughout the specialty metals industry to cast large alloy ingots. The VAR process is carried out in a vacuum with the aim of melting a large consumable electrode (.4 m in diameter and 3000 kg in mass and larger) in such a way that that the resulting ingot has improved homogeneity. The VAR control problem consists of adjusting arc current to control electrode melt rate, which also depends on the electrode temperature distribution and adjusting electrode ram speed to control the arc gap between the electrode and the ingot. The process is governed by a 1 dimensional heat conduction partial differential equation with a moving boundary, which leads to an infinite dimensional, nonlinear system. In addition to the process nonlinearity, the inputs and all of the available measurements are corrupted with noise. In order to design a controller and a Kalman based estimator for this process, integral methods are used to derive a set of two coupled nonlinear ordinary differential equations in time, which capture the steady state and transient characteristics of melting in a VAR furnace. The model with the experimentally measured noise is then used to construct an estimator and a controller. The system can be described by two state variables that change in time: thermal boundary layer and melted length or alternatively electrode gap. The reduced order model compares favorably to an accurate finite difference model as well as melting data acquired for Ti-6Al-4V. It will be shown how this model can be used to obtain dynamic closed loop melt rate control while simultaneously controlling electrode gap. This controller and estimator were tested on a laboratory furnace at Timet.
Developing Complete Prediction Capability for Thermal Damages in Finish Machining of a Hardened Steel
Authors: Shi Jing , Liu C. Richard
Published: April 2008

The material thermal damages in hard turning can be classified as re-tempering and re-quenching, and the capability of predicting both damages is critical to obtaining optimal machining parameters for best part service performance. In this study, thermal damages were represented by material hardness change, and models for re-quenching and re-tempering were constructed through heat treatment experiments. The model for re-tempering describes hardness change based on material thermal history, while the re-quenching model defines material hardness as a function of material quenching temperature. In the meantime, a valid finite element (FE) model was adopted to calculate the material temperature histories in 3D hard turning. The obtained thermal histories were fed into the damage models, and thus the distributions of thermal damages beneath machined surfaces could be predicted.
Adaptive Resonant Mode Acoustic Controller
Authors: Smith Adam K. , Vipperman Jeffrey S. , Budny Daniel D.
Published: April 2008

Helmhotz resonators are popular devices used for passive noise control. These apparatus can be designed to produce a maximum reduction over a narrow frequency range. The frequency of the resonator is dependent upon its volume and shape. Schemes have been proposed to adapt Helmholtz resonators, through changing physical parameters, such as volume and neck area. A recent study by Bisnette and Vipperman (2004) has modeled the passive Helmholtz resonators and realized them electronically in a process that is similar to positive position feedback control in structures. One key difference is the need for phase compensation of the speaker dynamics, which is accomplished with an all-pass filter. Recent extensions to this control method have examined the advantages of using band-pass versus the low-pass resonant filters as well as higher-order Butterworth bandpass filters. Bandpass filters are found to simplify the multi-modal design process by reducing interaction of adjacent modes. Additional refinements include the adaptation of system parameters. By adapting controller gain, damping and control frequency are examined and optimized. Adaptation of system parameters is greatly facilitated through the electronic realization.
Effect of Metal Coating on FRP Blade Lightning Failure for Wind Power Generators
Authors: Sakamoto H. , Takebayashi A. , Hanai M.
Published: April 2008

In Japan, with the recent increase in wind power generator installations, the incidence of lightning damage to FRP blades is increasing. Lightning damage is a significant issue in Japan since lightning in Japan seems severer than that in Europe or the US. In Kochi, Japan, six 600-750 kW grade generators have been installed, and some have been damaged by lightning several times. To resolve this problem, the Kochi University of Technology received a request in 2002 from the Kochi prefectural government for research into lightning protection. After surveying the literature and questioning related organizations such as NREL and Toray USA, experiments to protect against lightning damage to FRP blades of wind power generators were planned. Half size models and two 1/4 parts of a full size 250kW blade were prepared as specimens for this research. The method investigated to protect against lightning damage was metal coating. The aim being to protect against blade failure by using metal coating in actual field situations; by using a 1/2 size model and the full size blade specimens in an experimental situation. As in previous experiments, these ones were mainly conducted in the Toshiba Hamakawasaki High Voltage High Power Testing Laboratory. This Testing Laboratory is one of the biggest test laboratories for experiments involving high voltages and large currents.
Reduction of Rotating Imbalance Measurement Variation Resulting From Test Apparatus Redesign
Authors: Sweeney Shannon K. , Fisher Kenneth J.
Published: April 2008

A case study is presented describing an undergraduate MET capstone design project aimed at reducing the measurement variation of rotating imbalance during the testing of vehicular powertrain products. Primary focus involved the redesign of the rotor assembly interfacing the balance machine and the product. The project entailed the implementation of innovative statistical methods discovered during the ongoing applied research activities of the faculty advisor. These methods were conveyed to the students who were charged with their application during the project. Tasks assigned to the students included the evaluation of existing measurement variation, identification of sources of measurement variation, redesign of the test apparatus to reduce the sources of variation, and quantification of the impact of redesign on measurement variation. The redesign of the rotor assembly and the marked reduction in measurement variation resulting from the design changes are described within the paper. The case study provides an example of the successful integration of technology development derived during the advising faculty’s innovative applied research with technology application by students during a successful undergraduate capstone student design experience.
Boiling Curves and Visual Observations of Subcooled Flow Boiling of Water Over a Horizontal Plate Heater in a Rectangular Channel
Authors: Lee Ho Sung , O’Neill Andrew T.
Published: April 2008

A 20-mm-width × 30-mm-length flat copper heater in a 30-mm-width × 20-mm-height cross-sectional rectangular channel was used to simulate the forced convection flow and subcooled flow boiling in standard engine cooling systems. To visualize the effects of velocity, subcooling, and pressure, a high-speed camera was used. The subcooling ranged from 10°C to 50°C, the velocity from 0.5 m/s to 4 m/s, the pressure from 1 atm to 2.6 atm, and the heat flux from 0 W/cm2 to 80 W/cm2. The measured forced convection and boiling curves of water were presented along with high-speed photographs.
Impulse-Frequency Response and EIS Based NDE for Characterizing Bond Integrity of Adhesive Joints Subjected to Environmental Degradation
Authors: Anakapalli Manoj , Mantena P. Raju , Al-Ostaz Ahmed , Hwang S. Jimmy
Published: April 2008

Single-Lap Joint (SLJ) and three-point end-notched flexure (ENF) joint configurations were used to bond 1” × 1/8″ (25.4mm × 3.175mm) aluminum 2024 T-4 adherends using a range of 3M™ high performance pressure sensitive adhesives (Adhesives 69, 73 and 85) and VHB™ acrylic foam tapes (Foam 41, 50, 52). Batches of bonded specimens were subjected to two types of aggressive environments simulating extreme service conditions: freeze-thaw cycling from 10°F to 50°F at 6 cycles per day (ASTM C666 Procedure A) for 21 days with samples immersed in water; heat-cool cycling (with 90% of maximum recommended temperature by the manufacturer of both acrylic foam and adhesive transfer tapes attained at 70% relative humidity) and 3 cycles per day for 21 days. Electrochemical Impedance Spectroscopy (EIS) and Fast Fourier Transform (FFT) based impulse frequency response vibration Non-Destructive Evaluation (NDE) techniques were used to monitor overall bond integrity.
Quasi-Static Lap Shear and Dynamic Impact of High Performance VHB™ Acrylic Foam and Adhesive Transfer Tape Bonded Aluminum Joints Subjected to Environmental Degradation
Authors: Anakapalli Manoj , Mantena P. Raju , Al-Ostaz Ahmed , Hwang S. Jimmy
Published: April 2008

A range of 3M™ VHB™ acrylic foam tapes and high performance adhesive transfer tapes were used to bond 1” × 1/8″ (25.4 mm × 3.175 mm) aluminum 2024 T-4 adherends in single-lap joint (SLJ) and three-point end-notched flexure (ENF) configurations. Three types of 0.045” thick double-coated acrylic foam tapes: Foam 41, 50 and 52 (firm, soft and softer), and three types of adhesive transfer tapes: Adhesives 69, 73 and 85 (0.005”, 0.01” and 0.005” thick, respectively) were used for this study. The samples were subjected to two types of aggressive environments simulating extreme service conditions: freeze-thaw cycling from 10°F to 50°F at 6 cycles per day (ASTM C666 Procedure A) for 21 days with samples immersed in water; heat-cool cycling (with 90% of maximum recommended temperature by the manufacturer of both acrylic foam and adhesive transfer tapes attained at 70% relative humidity) and 3 cycles per day for 21 days. Initially the impulse-frequency response vibration and electrochemical impedance spectroscopy (EIS) techniques were used for monitoring bond quality nondestructively and selecting the best out of 250 fabricated samples. After obtaining baseline data, the specimens were subjected to quasi-static lap-shear and dynamic impact loading to compare their lap-shear failure loads and shear energy along with the impact load and energy absorbed.
Design Process Error-Proofing: Strategies for Reducing Quality Loss in Product Development
Authors: Chao Lawrence P. , Ishii Kosuke
Published: April 2008

Design errors are a major source of quality loss in industry today. “Design Process Error-Proofing” seeks to prevent errors during product development by adapting quality management techniques. Poka-yoke solutions used in manufacturing and operation aim to prevent mistakes from occurring or detect them immediately after they are committed. The goal of design process error-proofing is to extend this strategy and develop innovative structured methods and tools that understand, predict, and prevent design errors. Because the research topic is fairly new, case studies are used to both explain and demonstrate the usefulness of solutions. Through a series of design initiatives at leading global organizations, important lessons were identified in the treatment of design errors. This paper discusses these error-proofing strategies and results.
Design of a Bistable Compliant Locking Mechanism for New Generation Mirror Actuators
Authors: Somraj Phaniendra , Hsu Hung-Yao
Published: April 2008

A New Generation Spherical Actuator is designed for rear view mirrors in modern automobiles. The present paper portrays the design of a bistable compliant locking mechanism for this New Generation Mirror Actuator. A Functionally binary pinned-pinned segment is also designed for bistability. Discussion on related topics like bistable mechanisms, compliant mechanisms and rigid body mechanisms becomes the foundation for this research. A testing rig is constructed here to test the design. The design met the required attributes to be compliant and bistable, and it also emphasized on decreasing the number of parts in the whole assembly of the spherical actuator to minimize the total production cost.
A Study on a Intelligent Controller for Vibration Control of Semi-Active Suspension System
Authors: Ke Zhang , Shiming Wang
Published: April 2008

The physical model of semi-active quarter-coach suspension was established based on the theories of Buckingham’s Pi theorem in this paper. According to the characteristics of the semi-active suspension, a new intelligent control algorithm based on the Fuzzy logic control and cerebellar model articulation control techniques-Fuzzy cerebellar model articulation control (FCMAC) was presented and used to perform online control of semi-active suspension for the first time, novel weight-update laws were derived that guarantee the stability of closed-loop system, both information retrieval and learning rules were described by algebraic equations in matrix form. The results of experiment of closed -loop excited by three typical vibration signals showed that FCMAC control strategy can reduce the value of mean square root of vertical acceleration for semi-active suspension system to be lower 23%, 25% and 18% compared with the traditional control strategy such as PID.
Electrorheological Response of Polyaniline Particles Embedded in Cross-Linked Poly(Dimethyl Siloxane) Networks
Authors: Hiamtup Piyanooth , Sirivat Anuvat
Published: April 2008

Electrorheological characteristics of poly (dimethyl siloxane) (PDMS) networks containing camphorsulfonic acid (CSA) doped-polyaniline (PANI) particles were investigated. Samples were prepared by dispersing fine polyaniline particles into cross-linked PDMS. Rheological properties of the PANI/PDMS blends were studied in the oscillatory shear mode in order to study the effects of electric field strength, crosslink density of the matrix, particle concentration, and operating temperature on their electromechanical responses. The electrostriction of the blends were observed as a result of an attractive force among polarized particles embedded in the network. The sensitivity values of blends are defined as the storage moduli at any applied electric field subtracted by those values at zero electric field, and divided by the moduli at zero field. They were found to increase about 10-50% when electric field strength was increased to 2 kV/mm. These moduli values increased with particle concentration and temperature but they decreased with crosslink density of the matrices.
Apparent Wall Slip in Capillary Rheometry of Viscoplastic Liquids
Authors: Souza Mendes Paulo R. , Siffert Jose´ R. R. , Dutra Eduardo S. S.
Published: April 2008

We employ a recently proposed viscosity function (Souza Mendes and Dutra, 2004) to analyze the fully developed flow of yield-stress liquids through tubes. We first show that its dimensionless form gives rise to the so-called jump number, a novel material property that measures the shear rate jump that the material undergoes as the yield stress is reached. We integrate numerically the momentum conservation equation that governs this flow together with the generalized Newtonian Liquid model and the above mentioned viscosity function. We obtain velocity and viscosity profiles for the entire range of the jump number. We show that the friction factor f.Re curves display sharp peaks as the shear stress value at the tube wall approaches the yield stress. Finally, we demonstrate the existence of sharp flow rate increases (or apparent slip) as the wall shear stress is increased in the vicinity of the yield stress.
Plate Electroporation: A Numerical Study of Factors Affecting Thermal Damage
Authors: Becker S. M. , Kuznetsov A. V.
Published: April 2008

Electroporation is an approach used to enhance the transport of large molecules to cell cytosol in which a targeted tissue region is exposed to a series of electric pulses. The cell membrane, which normally acts as a barrier to large molecule transport into the cell interior, is temporarily destabilized due to the development of pores in the cell membrane. Consequently agents that are ordinarily unable enter the cell are able to pass through the cell membrane. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with joule heating. This paper explores the thermal effects of various geometric, biological, and electroporation pulse parameters including the blood vessel presence and size, plate electrode configuration, and pulse duration and frequency. A three-dimensional transient finite volume model of in vivo parallel plate electroporation of liver tissue is used to develop a better understanding of the underlying relationships between the physical parameters involved with tissue electroporation and resulting thermal damage potential.
Performance Comparison of Numerical Procedures for Efficiently Solving a Microscale Heat Transport Equation During Femtosecond Laser Heating of Nanoscale Metal Films
Authors: Kumar Ravi Ranjan , McDonough J. M. , Mengu¨c¸ M. P. , Kunadian Illayathambi
Published: April 2008

An alternative discretization and solution procedure for implicitly solving a 3-D microscale heat transport equation during femtosecond laser heating of nanoscale metal films has been developed (Kunadian et al. [1]). The proposed numerical technique directly solves a single partial differential equation, unlike other techniques available in the literature which splits the equation into a system of two equations and then apply discretization. The present paper investigates performance of its split and unsplit methods of solution via numerical experiments using Gauss–Seidel, conjugate gradient, generalized minimal residual and δ-form Douglas–Gunn time-splitting methods to compare the computational cost involved in these methods. The comparison suggests that the unsplit method [1] employing δ-form Douglas–Gunn spatial time-splitting is the most efficient way in terms of CPU time taken to complete the simulation of solving the 3-D time dependent microscale heat transport equation.
Evaluation of Thermal and Mechanical Properties of Carbon Nano Fiber Reinforced SC-15 Epoxy
Authors: Pervin Farhana , Zhou Yuanxin , Rangaree Vijay , Jelanee Shaikh
Published: April 2008

In the present investigation we have developed a novel technique to fabricate nanocomposite materials containing SC-15 epoxy resin and carbon nano fiber (CNF). A high intensity ultrasonic liquid processor was used to obtain a homogeneous molecular mixture of epoxy resin and carbon nano fiber. The carbon nano fibers were infused into the part A of SC-15 (Diglycidylether of Bisphenol A) through sonic cavitations and then mixed with part B of SC-15 (cycloaliphatic amine hardener) using a high speed mechanical agitator. The trapped air and reaction volatiles were removed from the reaction mixture using high vacuum. TGA, DMA and 3-point bending tests were performed on unfilled, 1wt. %, 2wt. % and 4wt. % CNF filled SC-15 epoxy to identify the loading effect on thermal and mechanical properties of the composites. The flexural results indicate that both modulus and strength increased with increasing loading percentage of CNF. DMA studies also revealed that filling the carbon nano fiber into epoxy can improve storage modulus and Tg compared to neat system. However, TGA results show that thermal stability of composite insensitive to the fiber content. The fracture surfaces, dispersions and morphological changes of composites were studied by scanning electron microscope (SEM). These results indicate that the carbon nano fiber is about 200nm in the diameter and 20–100um in the length and are nearly uniformly dispersed over the entire volume of the resin.
Integrating Technical Communications Into an Early Design Course
Authors: Bannerot Richard , Wilson Chad , Hodges Colley
Published: April 2008

This paper describes the integration of a significant amount of instruction and technical communications assignments into an early design course in the BSME program at the University of Houston. While many of the examples presented in this paper were initially introduced into the course without outside involvement, many more have been developed and the initial assignments have been improved through collaborations with the recently established University of Houston Writing Center (2000) and the even newer (2004) Technical Communications Across the Curriculum Program in the Cullen College of Engineering. Approximately 55% of an individual’s course grade is based on a variety of team (18%) and individual (37%) writing and presentation assignments. In many ways, these assignments are similar to those given in a traditional technical communications course. The difference is that many of these assignments are directly linked to course material including, the design process, working in teams on design-fabricate-and-compete projects, engineering ethics, and intellectual property issues. The paper provides details of these activities (including examples of assignments) and the results from student surveys requesting feedback on their effectiveness.
Development of a Nanosystems Engineering Degree
Authors: Hegab H. , Palmer J. , Napper S.
Published: April 2008

Nanotechnology is science at the molecular level. Like biotechnology and information technology, it has tremendous potential to greatly change the world in which we live. Nanosystems engineering can be considered the branch of engineering that deals with materials and devices smaller than 100 nanometers (1 nanometer is a billionth of a meter), especially with the manipulation of individual molecules. Student interest and industry growth in this field highlight the need for a baccalaureate program in this area. The College of Engineering and Science at Louisiana Tech University has developed a new undergraduate degree in nanosystems engineering. The main objectives of this program are (a) to train undergraduate students in experimental, theoretical, and computational aspects of engineering and science as applied to the development and use of nanotechnology; and (b) renovate and revitalize traditional engineering curricula such as mechanical engineering or materials science/ engineering through new nanosystems courses and instructional modules. We describe a new undergraduate Bachelor of Science in Nanosystems Engineering curriculum which has a strong interdisciplinary emphasis. The Nanosystems Engineering Program draws on the strengths of all the basic sciences (chemistry, physics, and biology) and existing integrated engineering and science programs within the college at the freshman and sophomore levels. Graduates with a nanosystems engineering degree will have many opportunities at the boundaries of traditional engineering due to the cross-disciplinary nature of their degree. We expect many of the graduates of this program may choose to pursue research-based careers by moving on to graduate study or working at government laboratories and/or research centers. Graduates who wish to work in a commercial environment will find ever expanding opportunities in the many new nanotechnology companies that are emerging.
Characterization of Mn-Zn Magnetic Fluid for Cooling Applications at Ambient Temperature
Authors: Gutierrez Gustavo , Catan˜o Juan , Melendez Carmen , Perales-Perez Oscar , Tomar M. S. , Calderon Eric
Published: April 2008

There are presently many applications using nanofluids in thermal engineering. Some examples include the use of nanoparticles in conventional coolants to enhance heat transfer rate by increasing its thermal conductivity. Other applications include the sealing of bearing cases and sealing of rotary shafts. Even at low weight concentration, thermal conductivity increases significantly. In biotechnology, magnetic nanoparticles have been proposed for thermal treatment of tumor using nanoshells and alternating magnetic fields to generate heat in localized points. This paper evaluates the use of aqueous ferrofluid composed of MnxZn1−xFe2O4 nanoparticles for cooling applications in the ambient temperature range. The use of ferromagnetic fluid for cooling applications represents an encouraging alternative to traditional methods; the fact that the fluid can be pumped with no moving mechanical parts, using the magnetocaloric effect, can be a great advantage for many applications where maintenance or power consumption are undesirable. A magnetic fluid suitable for this specific application has to have certain specific properties, like low Curie temperature, high magnetization, low viscosity and high specific heat. The selection of this ferrofluid is made based on its low Curie temperature (Tc), high saturation magnetization (Ms), low viscosity and high specific heat. The selection of a Mn-Zn ferrite-based aqueous ferrofluid was made based on its low Curie temperature compared with more commercially common magnetite-based ones. The synthesis of the ferrite nanoparticles was carried out by chemical precipitation and the process is described further on. Magnetic characterization of MnxZn1−xFe2O4 nanoparticles included the determination of Ms as a function of composition at 300K and the dependence of Ms with temperature for a specific ‘x’ value. Both types of measurements were carried out by using SQUID (Superconducting Quantum Interference Device) magnetometer.
Projection Network for Unsupervised Pattern Classification
Authors: Li C. James , Jansuwan C.
Published: April 2008

Projection network, being a non-linear dynamic system itself, has been shown to be superior to static classifiers such as neural networks in some applications where noise is significant. However it is a supervised classifier by nature. To extend its utility for unsupervised classification, this study proposes an unsupervised pattern classifier integrating a clustering algorithm based on DBSCAN and a dynamic classifier based on the projection network. The former is used to form clusters out of un-labeled data and eliminate outliers. Then, significant clusters in terms of size are identified. Subsequently, a system of projection networks is established to recognize all the significant clusters. The unsupervised classifier is tested with three well-known benchmark data sets (by ignoring data labels during training) including the Fisher’s iris data, the heart disease data and the credit screening data and the results are compared to those of supervised classifiers based on the projection network. The difference in performance is small. However, the ability of unsupervised classification comes at a price of a more complex classifier system and the need of data pre-conditioning. The former is because more than one cluster could be formed for a class and therefore more computational units are needed for the classifier, and the latter is because increased similarity of data after clustering increases the chances of numerical instability in the least square algorithm used to initialize the classifier.
Air Flow Turbulent Fluctuations in a Centrifugal Fan
Authors: Sierra F. Z. , Lara H. C. , Kubiak J. , Siqueiros J. , Garcia J. C. , Urquiza G.
Published: April 2008

In this work air flow turbulent fluctuations within the volute-impeller interaction region in a centrifugal fan are analyzed. The fan is part of one group of four similar units that provide the necessary air into a steam generator, in a power plant of 70 MW capacity. A numerical approach based on the finite volume method has been employed to solve the full set of Navier-Stokes equations in 3-D. Multiple reference frame was used to simulate the circular motion of the rotor inside the volute which remained static as well as the air entrance and exit sections. The whole domain was divided into 1.350 × 106 cells. Additional terms due to centrifugal and Coriolis forces were taken into account in the computation. The turbulence was addressed using one model based on renormalized group theory, RNG. Emphasis is focused on describing the velocity field within the annulus in between the rotor and the volute and its fluctuations. One first set of results indicate that the highest velocities appear in the region close to the blades tip, but they decay immediately after entering the annular volute-impeller region. Over there, the flow develops into two zones which are well defined through dynamic and static pressure contours. The results show how the magnitude of turbulence intensity varies according to different operation conditions of the fan, taking as fixed parameter the pressure at exit. The behavior of turbulence in the radial direction for a number of flow sections, starting from the cutter at the exit of the fan are examined as well.
A Variational-Asymptotic Cell Method for Periodically Heterogeneous Materials
Authors: Yu Wenbin
Published: April 2008

A new cell method, variational-asymptotic cell method (VACM), is developed to homogenize periodically heterogenous anisotropic materials based on the variational asymptotic method. The variational asymptotic method is a mathematical technique to synthesize both merits of variational methods and asymptotic methods by carrying out the asymptotic expansion of the functional governing the physical problem. Taking advantage of the small parameter (the periodicity in this case) inherent in the heterogenous solids, we can use the variational asymptotic method to systematically obtain the effective material properties. The main advantages of VACM are that: a) it does not rely on ad hoc assumptions; b) it has the same rigor as mathematical homogenization theories; c) its numerical implementation is straightforward because of its variational nature; d) it can calculate different material properties in different directions simultaneously without multiple analyses. To illustrate the application of VACM, a binary composite with two orthotropic layers are studied analytically, and a closed-form solution is given for effective stiffness matrix and the corresponding effective engineering constants. It is shown that VACM can reproduce the results of a mathematical homogenization theory.
Nano-Gap Piezoelectric Resonators for Mechanical RF Magnetic Field Modulation
Authors: White C. D. , Piazza G. , Stephanou P. J. , Pisano A. P.
Published: April 2008

Novel piezoelectric MEMS resonators with magnetic shielding have been developed to mechanically generate RF magnetic fields in the MHz frequency range from static magnetic fields. Thermally evaporated thin film nickel iron (NiFe) (10 to 20 nm) was deposited with a saturation flux density of 0.5 T, coercivity of 500 A/m and a high relative permeability of 3.7 × 103. Aluminum nitride (AlN) resonators developed for high frequency operation, resonate in a contour mode to increase and decrease a gap surrounding the resonator. This gap, 200 to 350 nm, is formed using a silicon sidewall deposition as a sacrificial spacer. Resonators with frequencies up to 60 MHz have been fabricated and tested.
Non-Equilibrium Molecular Dynamics Approach for Nano-Electro-Mechanical Systems: Nano-Fluidics and Its Applications
Authors: Kim Changsung Sean
Published: April 2008

A three-dimensional non-equilibrium molecular dynamics code has been developed and evaluated to provide fundamental understandings of nano-fluidics at molecular level. Intermolecular energy and force between fluid-fluid and fluid-wall particles were all included. Molecular dynamics results were verified by simulating both homogeneous and heterogeneous flows in a nano-tube and then compared with the classical Navier-Stokes solution with non-slip wall boundary conditions. At equilibration state, the macroscopic parameters were calculated using the statistical calculation. Liquid argon fluids within platinum walls were simulated for a homogeneous system. Also positively charged particles are mixed with water-like solvent particles to investigate the non-Newtonian behavior of the heterogeneous fluid. For an electrowetting phenomenon, a positive charged droplet moving on the negative charged ultra thin film was successfully simulated and compared with a macroscopic experiment. Nano-jetting mechanism was identified by simulating droplet ejection, breakup, wetting, and drying process in a consequent manner. In addition, conceptual nano/micropumps using electrowetting phenomenon are simulated. The present molecular dynamics approach showed its promising capability for the wide range of NEMS/MEMS applications
Characterizing the Effect of 319 Aluminum Microstructure on Machinability: Part 1 — Model Development
Authors: Hu Xuefei , Sutherland John W. , Boileau James M.
Published: April 2008

This two-part paper is directed at the development of a machining force model that addresses key microstructural features of 319 Aluminum. In Part 1 of this paper, a machining force model is presented that incorporates microstructural effects. Secondary Dendrite Arm Spacing (SDAS) is identified as a significant microstructure feature of 319 aluminum in terms of machinability, and the SDAS is related to the solidification rate. A new material constitutive relationship that incorporates SDAS microstructure effects is proposed. In Part 2 of this paper, the results from material tests and machining experiments are presented. A new methodology for estimating parameters within the material constitutive model is described, and force model predictions are compared with the results from machining tests. The comparison reveals an excellent agreement between measured and predicted forces.
Singulation of Electronic Packages With Abrasive Waterjets
Authors: Hashish Mohamed
Published: April 2008

Abrasive waterjets were used for the first time to commercially singulate electronic chips such as those used for flash memory cards found in digital cameras, cell phones, and USB storage devices. Cutting these components requires high cutting speed, high edge quality, accuracy, and precision. For example, a minimal accuracy needed is about 0.1-mm and a minimum Cpk of 1.33. A relatively small AWJ (~ 0.38 mm) was successfully used to accurately cut chips at speeds of 20 mm/s to 60 mm/s. It was determined that the use of machine vision is critical to meeting the accuracy requirements. The cutting process consisted of piercing starting holes and then cutting shaped pattern cuts to contour the chip components. Drilling holes was performed without delamination and the cutting speed was optimized to meet the intricate chip geometry. Because of the relatively high volume of components to be cut, requiring around the clock duty, process and machine reliability are of critical importance. This paper discusses the results and observation of the cutting process as well as the performance of the system.
Human Behavior in Evacuating a Building: A Problem Definition
Authors: Sillem Simone , Wiersma J. W. F. , Ale B. J. M.
Published: April 2008

There are different phases in which attempts can be made to prevent an emergency situation from happening or to fight its consequences when it does occur. These phases describe all activities that are aimed at increasing safety and can be represented schematically. This representation is called the safety chain. This paper looks at the phases of the safety chain where human behavior in evacuation can be influenced to mitigate the outcomes of an occurring emergency situation. A literature research has been done and the problems with human behavior are identified. Possibilities for further research are given, as well as the contours of a research project that will be carried out by the end of this year at Delft University of Technology.
Design Recommendations for Controlling the Jam-Clearing Hazard on Recycling Industry Balers
Authors: Mick T. , Means K. , Etherton J. , Powers J. , McKenzie E. A.
Published: April 2008

Between 1986 and 2002, there were 43 fatalities in the United States to operators of recycling industry balers. Of these fatalities, 29 involved horizontal balers that were baling paper and cardboard (Taylor, 2002). Balers often become jammed while the baling process is occurring, and the only way to remove the jam is manually. This requires an employee to place a limb of their body into the jamming area and remove the material that is causing the jam. While lockout and tagout procedures reduce the risk of hazardous energy being released, they can still be easily bypassed, ignored, or forgotten. Recent efforts to reduce machine-related injury and death involve the development of a control system for these machines that automatically detects hazardous operating conditions and responds accordingly. The system is being developed at the National Institute for Occupational Safety and Health (NIOSH). This system, JamAlert, automatically terminates the power to the machine when a jam is detected. JamAlert detects a jam by observing both the strain that is experienced by the shear bar of the baler and the hydraulic pressure at which the ram is operating. The strain that is experienced by the baler shear bar when a jam is initiated was calculated in this study through laboratory testing and finite element modeling. Design recommendations are presented on how best to tune the JamAlert’s operating program to most effectively control the jam-clearing hazard.
Ergonomics of Learning in a Very Descriptive Applied Human Factors Course
Authors: Rathod Mulchand S.
Published: April 2008

Teaching profession continues to hold its status as a noble profession and university faculty are held with high esteem by the general population. Some faculty teaching in engineering and technical programs have begun to address the pedagogy of learning in recent years. This is supported by a number of initiatives at the national level. Besides funding of such activities by organizations such as the National Science Foundation, engineering professional societies have created forums and awards to recognize and promote teaching and learning of engineering subject matter. This paper addresses an experiment in improved learning by students of a subject matter that is very descriptive and non-traditional as compared to most engineering subjects. The applied human factors course is an elective course for engineering technology (ET) students and a required course for the (non-technical) industrial design students from the College of Fine, Performing, and Communication Arts (CFPCA) at Wayne State University (WSU). Technical students are more comfortable with equations and formulas where as the non-technical students have practically no exposure to such things. Setting for this course was a multi-media distance learning laboratory and the teacher had an important task of not just covering the material, but to increase student interest to optimize their learning. Although all the teaching material for the course was prepared for presentation in power point, after a discussion with the class, it was decided to make the learning process different from the traditional teaching. The class was divided in three groups and each group was given a reading assignment covering one third of the material to be covered in each class session. Each group met on a regular basis going over its assignment and breaking up the task for each team member to lead presentation and discussion for the next class. Learning objectives addressed in the course included team work, effective communication, system design and implementation, continued student participation, and effective learning for long term retention besides the contents of the subject matter. Overall, students really felt they were learning a lot and achieving unexpected new presentation skills. This paper would summarize a very positive experience of all dealing with learning pedagogy.