bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Efficacy of a New Research-Oriented Peer Mentoring Program: YOU’RE@CU
Authors: Tsai Janet Y. , Kotys-Schwartz Daria , Ferguson Virginia , Louie Beverly
Published: August 2012

At the University of Colorado, Boulder, a new program designed to link graduate students with 1st and 2nd year undergraduate students through engineering research projects and mentoring relationships was initiated in Spring 2011. Your Own Undergraduate Research Experience at the University of Colorado (YOU’RE@CU) has three main goals: (1) increase retention of undergraduate students in engineering, particularly women and underrepresented minorities (URMs); (2) excite undergraduate student interest in research projects and future careers in academia or industry; (3) provide graduate students with training and hands-on mentoring experience with the expectation that this will positively influence graduate student choices to seek a career in academia. This paper illustrates the details of the YOU’RE@CU program during its pilot implementation in Spring 2011. The assessment strategy and methods are also explained, with presentation of qualitative data and discussion of the overall data analysis process.
Compression and Hysteresis Curves of Nonlinear Polyurethane Foams Under Different Densities, Strain Rates and Different Environmental Conditions
Authors: Alzoubi M. F. , Tanbour E. Y. , Al-Waked R.
Published: August 2012

Polyurethane (PU) closed cell foam samples with different densities were tested under loading and unloading compression tests at different temperatures and strain rates. Quasi-static compression tests were performed using the Lloyd LR5K Plus instrument at strain rates ranges from 0.033–0.267 s−1. Tests were conducted in a pre´cised enclosure to control the dependency of PU foam cells on temperature and humidity. In order to have an accurate comparison in compression and hysteresis curves for all tests; all PU foam samples were selected intentionally from the same foam block but with different location densities. Furthermore, all foam samples were tested in the direction of foam rise (thickness). First, PU foam samples were compressed with a circular platen up to 70% strain at different strain rates and different temperatures. Then, the platen was raised completely from the foam samples. During the experiment; stress-strain responses were measured and plotted for loading and unloading curves to determine stored energy, dissipation energy and peak stresses were calculated at 70% strain. Results have shown that PU foam sample responses under compression testing gets softer at higher temperatures when conducted at a constant strain rates. At constant temperatures, PU foam samples get harder at higher slip rates. Finally, both stored and dissipation energies were found to be dependent heavily on foam density, ambient temperature and strain rate.
Statistically Designed Beam Deflection Lab
Authors: Smith Natasha , Mativo John Mutungi
Published: August 2012

Two vital skills for an engineering graduate are the abilities to reason and communicate effectively. Laboratory work is one of the principle ways in which students exercise these competencies. In a typical undergraduate engineering course (particularly those at the freshman or sophomore level), laboratory exercises are often designed for students (rather than by them). They must simply follow procedures to find pre-determined results in order to “drive home” theoretical concepts. As a result, students are left with a poor concept of the purpose and power of experimentation, and consequently the laboratory experience detracts from rather than bolstering their critical thinking skills. A one factor at a time approach is often the default method for undergraduate engineering experiments, and while it is relevant for acquiring initial skills at the freshmen and sophomore levels, the approach may only promote lower level thinking skills. Even so, these experiences are pivoting in establishing sound engineering practices among students. In addition, statistical design of experiments could be explored for implementation for junior and senior level design courses. This project sought to provide an example of higher order thinking by performing a statistically-designed beam deflection experiment. The experimental objectives were to determine if load, span, geometry, and material affected the deflection of simply supported beams and to identify significant nuisance factors. Key nuisance effects included support stiffness, the reaction measurement procedure, and the effect of built-up members. In conclusion, the paper points out how undergraduate students could benefit from exposure and participation in such a design of experiments process even though students were not involved in this study originally.
Performance of a Multiple Stage EHD Gas Pump in a Square Channel
Authors: Mazumder A. K. M. Monayem H. , Lai F. C.
Published: August 2012

Earlier studies have shown that an electric field in the form of corona discharge can effectively produce air flow. Using this technique, it has been demonstrated that an electrohydrodynamic (EHD) gas pump can produce gas flows with a maximum velocity of 5 m/s. Its maximum performance of 34 L/s/W is better than that of conventional cooling fans used in personal computers. In this study, an EHD pump with two stages, each stage with 28 emitting electrodes, is tested for a wide range of operating voltages starting from the corona threshold voltage up to 28 kV for further improvement in its performance. To seek the relation between the pump performance and number of stages, the EHD gas pump is critically evaluated by experimental measurements and numerical simulations. The maximum performance of 34 L/s/W is achieved by using a total of 56 electrodes with 0.5 inch wide grounded plate in each stage.
Characterization of In-Pipe Acoustic Wave for Water Leak Detection
Authors: Khalifa Atia E. , Ben-Mansour Rached , Youcef-Toumi Kamal , Choi Changrak
Published: August 2012

This paper presents experimental observations on the characteristics of the acoustic signal propagation and attenuation inside water-filled pipes. An acoustic source (exciter) is mounted on the internal pipe wall, at a fixed location, and produces a tonal sound to simulate a leak noise with controlled frequency and amplitude, under different flow conditions. A hydrophone is aligned with the pipe centerline and can be re-positioned to capture the acoustic signal at different locations. Results showed that the wave attenuation depends on the source frequency and the line pressure. High frequency signals get attenuated more with increasing distance from the source. The optimum location to place the hydrophone for capturing the acoustic signal is not at the vicinity of source location. The optimum location also depends on the frequency and line pressure. It was also observed that the attenuation of the acoustic waves is higher in more flexible pipes like PVC ones.
Development of an Angularly Oscillating Wave Energy Converter
Authors: Yang Yingchen , Reyes Ruben , Gonzalez Carlos , Echevarria Sergio
Published: August 2012

The averaged power density of ocean waves is about 25 times as high as that of solar or winds. Yet, energy harvesting from ocean waves is far less competitive than that from solar and winds nowadays. The primary hurdle is the high installation/maintenance cost associated with wave energy harvesting devices. The present research focuses on the development of a wave energy converter (WEC) that is expected to have negligibly low cost on installation and maintenance. To achieve this goal, a new working mechanism is applied. The enabled WEC is a surface-floating device. It can be loosely anchored to the seabed through single-point slack mooring; that makes the installation as easy as anchoring a boat. The WEC uses wave-enabled angular oscillation to harvest energy. Such angular oscillation directly turns into nearly the same angular oscillation between the rotor and stator of a specially designed electric generator. The whole system is encapsulated in a rigid and watertight buoy — the hull of the WEC, thus the WEC is corrosion free. Furthermore, the only parts that subject to wear in the entire system are a couple of high-endurance bearings, which may make the WEC maintenance free in its designed lifespan (e.g., 5 years). In this paper, we present and discuss the design and testing of our first prototype WEC. Experimental exploration from hydrodynamic perspective was conducted in a wave tank to improve the shape design of the buoy, which plays a critical role on exciting large angular oscillation of the WEC in waves. Numerical simulation from electromagnetic perspective was carried out to guide the design of the electric generator; the resulted generator is capable of working efficiently in slow angular oscillation mode (e.g., at 1 Hz or lower).
A Design Approach for Improving the Vibroacoustic Characteristics of Plate Structures
Authors: Alshabatat Nabeel T. , Naghshineh Koorosh
Published: August 2012

This paper presents a design method to optimize the natural frequencies and to minimize the radiated sound power from vibrating plate-like structures. The design method involves creating dimples on the surface of the structure. The dimple can be defined as a local modification in the surface of a structure which has a spherical shape. Creating dimples does not change structural mass but affects its stiffness. Also, addition of dimples alters the plate mode shapes and as a result changes the radiated sound power from the plate. This method is cost-effective in comparison with other structural dynamics modification methods because it can be achieved through a one-step manufacturing method and because it enhances the dynamic behavior of platelike structures without additional weight or added joints.
Separation of Magnetic Beads in a Microfluidic Device: Modeling and Experimentation
Authors: Tsai Scott S. H. , Wexler Jason S. , Griffiths Ian M. , Stone Howard A.
Published: August 2012

We describe a microfluidic system that uses a magnetic field to deflect paramagnetic beads in the direction normal to the flow. Through modeling and experimentation, we study this system to separate beads by their magnetic properties and size. We also use a similar system to move the beads from one fluid stream to an adjacent miscible stream.
New Correlations for Thermal Resistances of Vertical Single U-Shape Ground Heat Exchanger
Authors: Liao Quan , Zhou Chao , Cui Wenzhi , Jen Tien-Chien
Published: August 2012

The effective pipe-to-borehole and pipe-to-pipe thermal resistances of vertical single U-shape ground heat exchanger are numerically studied. The non-uniform temperature distributions along perimeter of both borehole and outside diameter of two pipes are taken into account to evaluate both the pipe-to-borehole and pipe-to-pipe thermal resistances. The best-fit correlations for these two thermal resistances are proposed and compared with the available equations in the literature. It is found that the present correlations of effective pipe-to-borehole and pipe-to-pipe thermal resistances are more accurate than those of available formulas.
Using NURBs-Based Metamodels as Surrogate Spine Models for More Efficient Probabilistic Analysis
Authors: Pickett Bethany , Turner Cameron J. , Petrella Anthony
Published: August 2012

Probabilistic simulation methods have allowed for many advancements in the field of biomechanics, especially for the human spine. To accurately model a complex system such as the spine, the model must account for the differences that occur from one specimen to the next. These differences in material properties and anatomical shapes are described probabilistically. Accurately modeling the effects of these differences is important in biomechanics as no two people are exactly alike, yet building individual models of every person is impractical. Several authors have conducted research into more accurate ways to model biomechanical systems such as the spine, however the computational expense of performing analysis and optimization with these probabilistic simulation models still remains an issue, particularly with respect to the underlying Monte Carlo simulations. The research described in this paper investigates the use of Non-Uniform Rational B-splines (NURBs) based metamodels to reduce the cost of expensive probabilistic simulation models of the spine for analysis and optimization. Metamodels are simply mathematical approximations of a model or in other words, a model of models. Metamodels are widely used to represent the behavior of complex systems based on limited data from the original system model. Metamodels are often more computationally efficient to store and analyze than the original system models which they approximate. Using a Functional Spinal Unit (FSU) Finite Element Model, two different probabilistic NURBs-based metamodeling methods were developed and tested. Through the use of metamodels, a promising approach for reducing the computational time of running a Monte Carlo simulation was discovered.
Effects of Annealing on CuInGaSe2 Solar Cell Prepared by Magnetron Sputtering
Authors: Hexin Luan , Daming Zhuang , Jiang Liu
Published: August 2012

CuInxGa1−xSe2 (CIGSe) thin films have been deposited by magnetron sputtering from a CIGSe target and annealed in Se (Selenium) vapor atmosphere. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Raman, X-ray Fluorescence (XRF), Hall tester were used to observe and analyze the compositions, microstructures, surface morphologies and electronic properties of the films. After annealing, the performance of CIGSe films can be improved. The crystalline quality and electronic properties of annealed CIGSe films changed when the annealing temperature increases up to 350°C. CIGSe film with single chalcopyrite structure can be obtained when annealing temperature increases up to 400°C for 120 minutes. Se could be added into the thin films while annealing in Se vapor atmosphere. Cu-Se phase forms at the beginning of annealing and decreased with the increase of annealing time. In this work a cell with efficiency of 7.69% based on the sputtered and annealed CIGSe absorber was obtained.
Images Analysis of Horizontal Two-Phase Slug Flows
Authors: Morales R. E. M. , da Silva M. J. , Santos E. N. , Dorini L. , do Amaral C. E. F. , Alves R. F.
Published: August 2012

Multi-phase flow measurements are very common in industrial applications especially of the oil and gas industry. In order to study such pattern one can apply many different techniques such as capacitive probes, X-ray and gamma ray tomography, ultrasound transducers, wire-mesh sensors and high speed videometry. This article describes experimental study of water-air slug in horizontal pipes through non-intrusive image analysis technique. A flow test section comprising of a pipe of 26 mm internal diameter and 9 m long was employed to generate slug flows under controlled conditions. The behavior of the flow was studied using gas and liquid velocities between 0.3 m/s and 2 m/s with 6000 images (500×232 pixels) for each case. The algorithm comprises the automatic analysis of a sequence of frames in MatLab to measure flow characteristics such as Taylor bubble velocity and frequency applying morphological treatment. Finally, the parameters measured through the high speed videometry were compared with theoretical predictions showing that such method can be used to validate other types of sensors in experimental conditions.
Sustainability of Fiber Reinforced Composites: Status and Vision for Future
Authors: Kalla Devi K. , Dhanasekaran P. S. , Zhang Bangwei , Asmatulu Ramazan
Published: August 2012

Fiber reinforced polymer (FRP) composite products offer many significant environmental benefits such as light weight, superior mechanical properties, extended service life, low maintenance and resistance to corrosion. But until now it has been difficult to compare sustainability of different FRP materials and production for processes. Concern for the environment, both in terms of limiting the use of finite resources and the need to manage waste disposal, has led to increasing pressure to recycle materials. This paper focuses on two issues that must be addressed to ensure continued growth in FRP usage is the disposal of waste generated during product manufacturing and the disposal of the products at the end of their useful life. The major cost drivers for FRPs are labor and raw materials. The use of recycled FRPS offers low-cost raw materials. This paper presents a review of the current status and outlook of FRP composites recycling and re-manufacturing techniques. A future vision for the use of FRP composites with sustainability applications is underway at many university research institutes and in industries. This paper will also state the sustainability problems of fiber reinforced composite products, and potential solutions.
Numerical Simulations of Non-Newtonian Geophysical Flows Using Smoothed Particle Hydrodynamics (SPH) Method: A Rheological Analysis
Authors: Basu Debashis , Das Kaushik , Janetzke Ron , Green Steve
Published: August 2012

This paper presents computational results for two-dimensional (2-D) simulations of geophysical flows using the Smoothed Particle Hydrodynamics (SPH) method. The basic equations solved are the incompressible mass conservation and Navier-Stokes equations, and the discretization is carried out using the SPH method. The simulations are carried out for two problems. The first problem involved a 2-D dam-break problem with mud flow. The second problem involved non-Newtonian flow of deformable landslide on a mild slope. In both the simulations, the flow is assumed to be incompressible. In the present study, the mud flow materials are represented as non-Newtonian fluids with a Bingham model. The effects of the rheological formulation are assessed for the predicted mudflow shape. The simulation results are compared with the experimental data available in open literature. The velocity profiles and the free surface shape are in good agreement with the experimental data. To distinguish between the non-Newtonian model simulations and the Newtonian model, the dam-break simulations were also carried out using water and Newtonian models. The simulations reveal several distinctive flow features between the Newtonian and non-Newtonian approaches. The results of the simulations are of engineering interest in mitigation of natural hazards such as debris flows.
Virtual Robustness Evaluation of Turbine Structure Assemblies Using 3D Scanner Data
Authors: Forslund Anders , So¨derberg Rikard , Lo¨o¨f Johan , Galvez Alejandro Vega
Published: August 2012

In this paper, the functional robustness of a jet engine component is investigated. Located at the rear part of the engine, the Turbine Rear Structure (TRS) provides a support structure for the low-pressure shaft, while redirecting the exhaust flow from the low-pressure turbine to the exit nozzle. For larger engines, TRSs are fabricated assemblies consisting of cast, wrought and sheet metal parts. In a case study, virtual tools are used to examine how geometrical variation in cast parts of the TRS assembly affects performance. Variation data are obtained by scanning cast parts in a 3D laser scanner. The resulting data are fed into a CAD model as surface point parameters. The parts are then assembled virtually using CAT software. The assemblies are subsequently fed into a simulation platform where they are meshed, and CFD and FEM are used to evaluate the structural and aerodynamic effects of the variation. To quantitatively analyze the effects of variation, five cast parts with different geometrical variations are virtually assembled into 25 geometries and analyzed with respect to sixteen functional properties. Results show that geometric variation has a noticeable effect on performance. We believe this approach to be a useful tool in engine design. Being able to virtually examine the geometrical robustness of a design in early phases reduces the need for redesign loops. This leads not only to faster and less expensive product development, but also to better and more reliable engine designs.
Discrete Pressure Controls in IC Engine Lubricating Pumps
Authors: Rundo Massimo , Squarcini Raffaele
Published: August 2012

The paper presents two displacement controls for IC Engine lubricating vane pumps. The main feature is the variable setting of the absolute pressure limiter that can switch from a high to a low level when a minimum threshold value of engine speed or oil temperature is exceeded. This is obtained by venting the displacement actuator of the pump by means of a two positions electrovalve or a temperature sensitive valve. Aim is the reduction of the circuit pressure in the less critical engine operating conditions in order to decrease the absorbed torque. These controls are contrasted with a traditional fixed setting device in terms of overall energy absorbed by the pump in the NEDC cycle. Comparisons are performed with a lumped parameters simulation model able to replicate the operating conditions encountered by the pump during the driving cycle, in terms of oil temperature and circuit permeability. Outcomes from simulation have been validated by experimental tests on pumps prototypes. Tests have been performed on a rig where the load on the pump is generated by a proportional throttle valve controlled in a closed loop in order to reproduce, for each temperature and velocity condition, the resistance of the lubricating circuit. The study brings to evidence that with both systems a significant reduction of the absorbed energy can be achieved in the NEDC without detrimental effects on engine lubrication.
Effect of Radiation on Heat Transfer in Open-Cell Foams at High Temperature
Authors: Tseng Charles C. , Sikorski Ruth L. , Viskanta R. , Chen Ming Y.
Published: August 2012

There are a variety of foams that can be used in thermal protection and/or thermal insulation systems. At high temperature (> 1000 K) thermal radiation may be important or dominate heat transfer in the foam; however, studies based on more detailed thermal radiation analysis are limited. In this paper foams are considered to be semitransparent, because radiation can penetrate through the pore (or void) space and/or foam skeleton (solid matrix), depending on the materials from which the foams are made. Of particular interest of this study is to understand how the properties such as foam material its density, porosity, etc. affect thermal and radiant energy transfer. Physical and mathematical models are developed to account for conduction and radiation (absorption, emission and scattering) in the porous material. The spectral extinction coefficients of SiC foams are measured experimentally in the laboratory at room temperature, and the radiative transfer equation is solved using the spherical harmonics P1 and the Rosseland diffusion approximations. Parametric calculations have been carried out, and the results are reported in the paper for a range of parameters characterizing heat transfer in SiC foams of different porosities to identify desirable conditions for effectively reducing heat transfer in potential thermal protection concepts.
Designs of Multiple Microchannel Heat Transfer Systems
Authors: Zhang Jingru , Lin Po Ting , Jaluria Yogesh
Published: August 2012

In this paper, two different configurations of multiple microchannel heat sinks with fluid flow are investigated for electronic cooling: straight and U-shaped channel designs. Numerical models are utilized to study the multiphysics behavior in the microchannels and validated by comparisons with experimental results. Three responses, including thermal resistance, pressure drop, and maximum temperature, are parametrically modeled with respect to various variables such as dimensions of the channels, total number of channels, and flow rate. Multi-objective optimization problems, which minimize the thermal resistance and the pressure drop simultaneously, are formulated and studied. Physical constraints in terms of channel height, maximum temperature, and pressure are further investigated. The Pareto frontiers are studied and the trade-off behavior between the thermal resistance and the pressure drop are discussed.
Reliability-Based Optimal Cluster Mill Pass Scheduling
Authors: Malik Arif , Sanders John , Grandhi Ramana , Zipf Mark
Published: August 2012

Optimal pass-scheduling on cluster-type cold rolling mills, use to process flat metals, presents added challenges over conventional (vertical-stack) mills due to the complexity of roll arrangements. Cluster-type rolling mills not only pose difficulties in modeling deflections occurring in the multi-roll stack, they also impose the burden of modeling more sophisticated mechanisms used to adjust rolling force distribution and achieve desired strip flatness. In a competitive global market for very thin gauge strip, an advantage is gained through use of efficient mathematical set-up models that can adequately optimize the flatness actuators according to the target gauge reductions for each rolling pass. The mill’s process control computer should therefore determine a gauge reduction schedule leading to minimum number of passes, while simultaneously assigning nominal flatness control actuator set-points. Although recent developments in roll-stack deflection modeling using simplified, mixed finite element techniques have enabled more efficient roll-stack deflection modeling in 20-high and other cluster mills, the optimal pass-schedule problem is still complicated by the abundance of geometric and mechanical property variations in the strip or sheet to be processed. Furthermore, problems with strip flatness frequently arise because of uncertainties in roll diameter profiles resulting from variations in the roll grinding and roll wear patterns. In this paper, we extend recent work in pass schedule optimization (through improved rollstack deflection) by applying First Order Reliability Methods to rigorously account for various rolling process uncertainties. The results allow predictive probability constraints for strip flatness to be included in the optimization problem, thus enabling mill operators some insight and control into the likelihood of achieving desired strip flatness for a given rolling pass schedule.
Effects of High Initial Engine Start Up Speeds in Isothermal Fluid Flow and Piston Skirts EHL
Authors: Qasim Syed Adnan , Malik M. Afzaal
Published: August 2012

In the medium and high speed normal engine operating conditions a fully established elastohydrodynamic lubricating (EHL) film between the piston skirts and cylinder liner surfaces reduces friction and prevents adhesive wear. In the initial engine start up the absence of EHL film causes wear of piston skirts, especially at high speeds. In a few initial cold engine start up cycles, a highly efficient cooling system may not let the temperature to rise significantly and affect the viscosity and other characteristics of a lubricant. In view of the vulnerability of piston skirts to adhesive wear at high initial engine start up speeds, the hydrodynamic and EHL of piston skirts is modeled numerically. A 2-D Reynolds equation is solved by coupling the secondary piston motion and using a finite difference scheme. Transient hydrodynamic film thickness profiles are generated at a relatively high engine start up speed. In the EHL regime, the profiles of rising hydrodynamic pressures and film thicknesses are predicted by using the inverse solution technique in fully flooded conditions. The study is extended to a range of high engine start up speeds while using a fairly viscous engine lubricant. Numerical simulations show significant changes in the piston eccentricities and film thickness profiles in the hydrodynamic and EHL regimes at different start up speeds. Such variations alter the hydrodynamic and EHL pressures and visibly affect the load carrying capacity of the lubricant. This study suggests to optimize the high engine start up speed for the given viscosity grade engine lubricant when considering the vulnerability of skirts and liner surfaces to adhesive wear in the initial engine start up.
Long-Term Performance of Solid Oxide Stacks With Electrode-Supported Cells Operating in the Steam Electrolysis Mode
Authors: O’Brien J. E. , O’Brien R. C. , Zhang X. , Tao G. G. , Butler B. J.
Published: August 2012

Performance characterization and durability testing have been completed on two five-cell high-temperature electrolysis stacks constructed with advanced cell and stack technologies. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. The per-cell active area is 100 cm2. The stack is internally manifolded with compliant seals. Treated metallic interconnects with integral flow channels separate the cells and electrode gases. Stack compression is accomplished by means of a custom spring-loaded test fixture. Initial stack performance characterization was determined through a series of DC potential sweeps in both fuel cell and electrolysis modes of operation. Results of these sweeps indicated very good initial performance, with area-specific resistance values less than 0.5 Ω.cm2. Long-term durability testing was performed with a test duration of 1000 hours. Overall performance degradation was less than 10% over the 1000-hour period. Final stack performance characterization was again determined by a series of DC potential sweeps at the same flow conditions as the initial sweeps in both electrolysis and fuel cell modes of operation. A final sweep in the fuel cell mode indicated a power density of 0.356 W/cm2, with average per-cell voltage of 0.71 V at a current of 50 A.
Testing and Performance Analysis of NASA 5 cm by 5 cm Bi-Supported Solid Oxide Electrolysis Cells Operated in Both Fuel Cell and Steam Electrolysis Modes
Authors: O’Brien R. C. , O’Brien J. E. , Stoots C. M. , Zhang X. , Farmer S. C. , Cable T. L. , Setlock J. A.
Published: August 2012

A series of 5 cm by 5 cm bi-supported Solid Oxide Electrolysis Cells (SOEC) were produced by NASA for the Idaho National Laboratory (INL) and tested under the INL High Temperature Steam Electrolysis program. The results from the experimental demonstration of cell operation for both hydrogen production and operation as fuel cells is presented. An overview of the cell technology, test apparatus and performance analysis is also provided.
Incorporation of Hands-On Activities in Learning Nanomaterials
Authors: Jiao Lihong Heidi , Barakat Nael
Published: August 2012

For decades, nanomaterials, especially nanoparticles, have received extensive attention from the research community and have gained increasing importance in many industries. Growing production and utilization of nanomaterials result in a significant need for a relevant and skilled workforce. To meet these growing needs, the course “Fundamentals of Nanotechnology” was developed in the School of Engineering (SOE) at Grand Valley State University (GVSU) as one part of the Nanotechnology curriculum development plan sponsored by the National Science Foundation (NSF). Nanomaterials is one of the main topics covered in this course. Many concepts related to nanomaterials are both theoretical and abstract, which are difficult for students to grasp. This paper describes the hands-on lab activities incorporated to enhance the students’ learning and mastery of the subject. Through these hands-on activities, students learned to synthesize zero-dimensional and two-dimensional nanomaterials and characterized different properties of these nanomaterials. Students explored the physical and optical properties of nanoparticles, particle-to-particle aggregation, and applications of nanoparticles as sensors used in different fields. This paper presents the role of these hands-on activities in enhancing the students’ understanding of the theoretical nanomaterial concepts. These lab activities were assessed and results of this assessment from the first offering of the course are presented.
Features of a Trust Model for a Complex System
Authors: Hall Simin , McQuay William , Vance Eric
Published: August 2012

This research focuses on trustworthiness assessment and trust judgment in a complex system such as a distributed sensing system. In our previous IMECE paper, we employed an interdisciplinary approach to highlight trustworthiness characteristics and trust measurements in social sciences and cyberspace. In this paper, we elaborate on these findings and present features of existing models we can leverage in different applications. Trust properties and rules reported in this study are extracted from three classes of trust models that met our design constraints. These models are gleaned from the literature pertaining to wireless sensor networks, social networks, e-commerce, mobile ad-hoc, peer-to-peer, and distributed network services. The trust model provides upfront quantitative assurance and trustworthiness metrics for architecting/engineering new systems as well as a situation awareness/management assessment metrics once the system is deployed.
A Micro-Combined Heat and Power Laboratory for Experiments in Applied Thermodynamics
Authors: Flotterud John D. , Damm Christopher J. , Steffes Benjamin J. , Pfaff Jennifer J. , Duffy Matthew J. , Kaiser Michael A.
Published: August 2012

The purpose of this paper is to describe a micro-combined heat and power system, sized for residential distributed power generation, which was designed, constructed, and installed in the Advanced Energy Technologies Laboratory at the Milwaukee School of Engineering. The installation began as a Mechanical Engineering senior design project, in which students evaluated potential methods for distributed residential combined heat and power systems. Potential systems were evaluated based on cost-effectiveness in supplying the energy requirements of a typical residence in Milwaukee, WI, and they were also judged on their environmental impacts. Initial feasibility studies, undertaken with consideration of Milwaukee’s climatic conditions, found that a natural gas-fired, reciprocating engine-generator set with heat recovery exchangers could best meet the energy needs of a typical residence in a cost-effective manner. Following the design, fabrication, and installation of the system in the laboratory, the team designed and performed experiments to quantify the system performance. The system is currently configured to deliver 2 kW of electric power and 6 kW of thermal power, achieving an overall efficiency of 72%. The system is now used in two courses: Applied Thermodynamics, and Advanced Energy Technologies. During the cogeneration laboratories performed in these courses, students decide which measurements are needed and use the collected data to compute performance parameters, to complete an energy balance, and to perform a second-law analysis of the system.
Mixing Performance of Sewage Treatment Mixer at Different Rotational Speed
Authors: Fei Tian , Shi Wei-dong , Chen Bin , Cao Wei-dong
Published: August 2012

To investigate the mixing performance of submersible mixer, fluid in the pool mixed by sewage treatment mixer under three different rotational speeds were simulated using Fluent 6.3. Unstructured tetrahedron grid, MRF technology, RNG k–ε turbulence model and SIMPLE algorithm were adopted in the simulation. The velocity distributions on each section were analyzed, and the effective axial propelled distance and disturbance radius of water section of the sewage treatment mixer were studied. Using CFD, the optimum rotational speed of the mixer can be determined based on criteria for the velocity field in the pool. The way it is formulated now suggests that 740 r/min is the optimum speed. It will provide a reference for practical engineering applications of sewage treatment mixer.
Obtaining Experimental Closure for the VAT-Based Energy Equations Modeling a Heat Sink as a Porous Medium
Authors: Geb David J. , Chu Jonathan , Zhou Feng , Catton Ivan
Published: August 2012

Experimentally determining internal heat transfer coefficients in porous structures has been a challenge in the design of heat exchangers. In this study, a novel combined experimental and computational method for determining the internal heat transfer coefficient within a heat sink is explored and results are obtained for air flow through basic pin fin heat sinks. These measurements along with the pressure drop allow for thermal-fluid modeling of a heat sink by closing the Volume Averaging Theory (VAT)-based governing equations, providing an avenue towards optimization. To obtain the heat transfer coefficient the solid phase is subjected to a step change in heat generation rate via induction heating, while the fluid flows through under steady state conditions. The fluid phase temperature response is measured. The heat transfer coefficient is determined by comparing the results of a numerical simulation based on volume averaging theory with the experimental results. The only information needed is the basic material properties, the flow rate, and the experimental data. The computational procedure alleviates the need for internal solid and fluid phase temperature measurements, which are difficult to make and can disturb the solid-fluid interaction. Moreover, a simple analysis allows us to proceed without knowledge of the heat generation rate, which is difficult to determine precisely. Multiple pin fin heat sink morphologies were selected for this study. Moreover, volume averaging theory scaling arguments allow a single correlation for both the heat transfer coefficient and friction factor that encompass a wide range of pin fin morphologies. It is expected that a precise tool for experimental closure of the VAT-based equations modeling a heat sink as a porous medium will allow for better modeling, and subsequent optimization, of heat sinks.
Enhancing the Performance of Photovoltaic Powered Reverse Osmosis Desalination Systems by Active Thermal Management
Authors: Kelley Leah , Bilton Amy M. , Dubowsky Steven
Published: August 2012

Reverse osmosis (RO) is a well-known process for desalinating seawater and brackish groundwater. Desalination is energy-intensive, so using photovoltaic (PV) panels to power the process is an attractive and cost-effective concept, especially for community-scale systems. Increasing the system efficiency will lower the total cost of water produced, making the systems more economically competitive for a greater number of geographic locations. It is noted in this paper that the amount of water produced by a PV-powered RO (PVRO) system can be increased if the temperatures of the solar panel and the reverse osmosis feed water are actively managed. For a given level of solar radiation, a photovoltaic panel produces more power at a lower temperature. Also, for a given power, an RO system produces more clean water at a higher input (feed) water temperature. An active thermal management system is needed to exploit these complementary characteristics by cooling the solar panel and warming the RO feed water, increasing the amount of fresh water produced. This can be accomplished by running the RO feed water through a heat exchanger attached to the back of the solar panel, cooling it. Furthermore, the ability to cool the solar panels permits the addition of low-cost, flat-plate concentrating mirrors to be used with the PV panels, which further increases the PV power output. The flow of the water through the respective units must be actively controlled as there are limits for the maximum temperatures of both the RO water and PV panels. In this paper, a concept for an active PVRO thermal control system is presented. Simulations and experimental results show the effectiveness of this approach. In experiment, a 57% increase in fresh water production was achieved. These experimental results agree well with simulation models.
Measurements in Solid Propellant Plumes at Ambient Conditions
Authors: Height Jonathan L. , Donaldson Burl A. , Gill Walter , Parigger Christian G.
Published: August 2012

The study of aluminum particle ignition in an open atmosphere propellant burn is of particular interest when considering accident scenarios for rockets carrying high-value payloads. This study investigates the temperature of an open atmosphere Atlas V solid propellant burn as a function of height from the burning surface. Two instruments were used to infer this temperature: a two-color pyrometer and a spectrometer. The spectra were fitted to a model of energy states for aluminum monoxide. The temperature which provided the best match between the model and data was taken as the reaction temperature. Emissions above 30 inches from the surface of the propellant were not sufficiently strong for data reduction, perhaps obscured by the alumina smoke cloud. The temperature distribution in the plume increased slightly with distance from the burning surface, presumably indicating the delay in ignition and heat release from the larger aluminum particles in the propellant. The pyrometer and spectrometer results were found to be in excellent agreement indicating plume temperatures in the range of 2300K to 3000K.
Tracer Gas Mapping of a Beverage Cart Wake in a Twin Aisle Aircraft Cabin
Authors: Trupka A. Tristan , Hosni Mohammad H. , Jones Byron W.
Published: August 2012

An experimental study is performed in a mockup Boeing 767 cabin section consisting of eleven rows with seven seats per row. Carbon Dioxide (CO2) tracer gas is injected at a constant flow rate at a location of interest until concentrations in the cabin reach steady state. Ventilation equipment and flow rates representative of an actual aircraft are used for all experiments. Seats in the mockup are occupied by thermal manikins to simulate passenger heat load. A motorized beverage cart traverses the length of the cabin aisle passing by the injection location. The concentrations of tracer gas displaced by the cart are measured at locations throughout the cabin. Comparing these measurements to baseline readings taken with no cart movement, a map of the degree to which contaminant transport is affected by the beverage cart is calculated. The cabin mockup is supplied by 100% outdoor air through actual Boeing supply ductwork and linear diffusers along the cabin length above the aisles. The CO2 level is measured in the inlet air, measurement locations in the cabin, and exhaust air using nondispersive infrared (NDIR) sensors. Measured results are reported for all (54) seat locations downstream of the cart traverse/injection location for an injection location near the rear of the cabin. Analogous measurements are also conducted examining the effect of variation in cart speed and modified injection location.
An Investigation on the Mechanical Property of Unidirectional Basalt Fiber Composites
Authors: Hayakawa Tohru , Zhang Zhiyuan , Yang Yuqiu , Hamada Hiroyuki
Published: August 2012

Due to its low price and high mechanical property, basalt fiber (BF) is emerging as a novel reinforcement for fiber reinforced polymer (FRP) instead of glass fiber. The research about basalt fiber reinforced composites (BFRP) is insufficient in particularly for the long term life. Therefore, in order to apply BFRP into practical use, the current study was focused on mechanical property and their durable property. Firstly, one layer and six layers laminated unidirectional basalt fiber fabric reinforced unsaturated polyester were made by hand-layup method and tested by tensile, 3-point bending, short span bending and drill hole experiments. On the other hand, for the unidirectional basalt fiber fabric reinforced epoxy which are expected to be used in civil engineering, water and alkali solution immersion at various temperatures were carried out. The evolution of the mechanical properties along with ageing time was investigated. The results indicate that it is needed to improve the interface property between basalt fiber and polymer through surface treatment for enhanced durability performance.
Impact-Cutting and Regenerative Chatter in Robotic Grinding
Authors: Hazel Bruce , Rafieian Farzad , Liu Zhaoheng
Published: August 2012

This paper presents a study on the dynamic behavior of a flexible robot performing a grinding process. The ultimate goal is to understand whether regenerative chatter is the source of divergent vibrations observed when machining with a compliant robot. An important nonlinear characteristic of the dynamic response of the system is found and is included in the conventional approach to chatter analysis. Robotic machining is represented by a SDOF model. The steady-state response of this model to external forces is found to be repetitive impacts. The existence of this process is justified theoretically without invoking any self-exciting regenerative effect. High-speed camera observations during operation confirm the existence of such a vibro-impact process. To investigate stability, the robotic holder’s dynamic equation is excited by a forcing function representing impulse forces during cutting impacts. Response to regenerative impact cutting forces is simulated. Zones of stable/unstable cutting were identified. This suggests that the regenerative mechanism may explain the onset of divergent vibrations in the application under study. Established regenerative chatter theory predicts an extensive stable cutting zone for a flexible robotic holder. A regenerative mechanism then would not be a probable source of instability. Considering that conventional analysis is based on linear responses, the existence of vibro-impact nonlinearity is illustrated and its effect is analyzed. This results in a more realistic stable cutting zone, better matching our experience.
Replenishment of Ultrathin Liquid Perfluoropolyether Z Films on Solid Surfaces
Authors: Mayeed Mohammed S. , Kato Takahisa
Published: August 2012

Applying the reptation algorithm to a simplified perfluoropolyether Z off-lattice polymer model an NVT Monte Carlo simulation has been performed. Bulk condition has been simulated first to compare the average radius of gyration with the bulk experimental results. Then the model is tested for its ability to describe dynamics. After this, it is applied to observe the replenishment of ultrathin (4 nm thickness) liquid films on solid flat carbon surfaces. The replenishment rate for trenches of different widths (8, 12 and 16 nm for molecular weight of 3840 g/mol and 12 nm for molecular weights of 2500 and 1700 g/mol) between two films of perfluoropolyether Z from the Monte Carlo simulation are compared to those obtained solving the diffusion equation using the experimental diffusion coefficients of Ma et al. with room condition in both the cases. Replenishment per Monte Carlo cycle seems to be a constant multiple of replenishment per second at least up to 2 nm replenished film thickness of the trenches over the carbon surface. Considerable good agreement has been achieved here between the experimental results and the dynamics of molecules using reptation moves in the ultrathin liquid films on solid surfaces.
Algorithm of Launched Vehicles Mass Calculation at the Early Stage of Designing
Authors: Gaynutdinova A. , Gaynutdinova T.
Published: August 2012

Launching mass of pilotless vehicle bounds with flight path. Required fuel mass depends from flight trajectory. Design calculation of vehicle mass and flight trajectory are in close bind. We suggest numerical algorithm of design calculation of vehicle flight mass and optimal characteristics of flight trajectory – initial flight-path angle and flight time to target.
Nano-Solutions or Macro-Failures? An Application of the Public Values Failure Model to the Purification of Water With Nanotechnologies
Authors: Schuelke-Leech Beth-Anne
Published: August 2012

New scientific discoveries and technologies can provide substantial benefits for addressing societal problems. They can also pose new challenges and risks. This paper presents the Public Values Failure Model (PVFM) which can assist engineers, managers, and policymakers in considering the broader implications of their work and technology’s impact on society. This model assists in identifying the public values associated with a problem and evaluating the potential public values failures associated with a proposed technical solution. The PVFM is demonstrated using the case of the application of nanotechnologies to water purification.