bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Subtalar Arthrodesis Alignment on Ankle Biomechanics
Authors: Jastifer James R. , Gustafson Peter A. , Gorman Robert R.
Published: October 2013

Background: The position, axis, and control of each lower extremity joint intimately affects adjacent joint function as well as whole limb performance. There is little describing the biomechanics of subtalar arthrodesis and none describing the effect that subtalar arthrodesis position has on ankle biomechanics. The purpose of the current study is to establish this effect on sagittal plane ankle biomechanics.

Methods: A study was performed utilizing a three-dimensional, validated, computational model of the lower extremity. A subtalar arthrodesis was simulated from 20 degrees of varus to 20 degrees of valgus. For each of these subtalar arthrodesis positions, the ankle dorsiflexor and plantarflexor muscles’ fiber force, moment arm, and moments were calculated throughout a physiologic range of motion.

Results: Throughout ankle range of motion, plantarflexion and dorsiflexion strength varies with subtalar arthrodesis position. When the ankle joint is in neutral position, plantarflexion strength is maximized in 10 degrees of subtalar valgus and strength varies by a maximum of 2.6% from the peak 221 Nm. In a similar manner, with the ankle joint in neutral position, dorsiflexion strength is maximized with a subtalar joint arthrodesis in 5 degrees of valgus and strength varies by a maximum of 7.5% from the peak 46.8 Nm. The change in strength is due to affected muscle fiber force generating capacities and muscle moment arms.

Conclusion: The clinical significance of this study is that subtalar arthrodesis in a position of 5–10 degrees subtalar valgus has biomechanical advantage. This supports previous clinical outcome studies and offers biomechanical rationale for their generally favorable outcomes.
Temperature Effect on Low Velocity Impact of Nanoclay Reinforced Polymers
Authors: Bayar Selen , Delale Feridun , Liaw Benjamin
Published: October 2013

The main objective of this study is to ascertain the effect of temperature on nanoclay reinforced polymers subjected to low velocity impact loads. Most of the studies for low velocity drop weight tests are on fiber or fabric reinforced polymers. In recent years nanoadditives such as nanoclay have been used to improve the fire retardation of composites. The low velocity drop weight testing undertaken under this research has the distinct goal of obtaining base line data for impact analysis of nanoclay reinforced polymers. First, polypropylene 3371 (PP) resin specimens with dimensions of 4″×4″×(1/8)″ reinforced with varying weight fractions of nanoclay (0%, 0.2%, 1%, 3%, 6% and 10%) and instrumented with strain gages were subjected to low velocity impact tests. The low velocity impact tests were carried out at an energy level appropriate for nanoadditive reinforced polymers and at various temperatures, from −65°F (−54°C) to 160°F (71°C). The variation of contact force, specimen deflection and energy imparted to the specimen with time and the variation of contact force with displacement were obtained at each temperature. Depending on the drop height, the weight used and the percentage of nanoclay reinforcement, the following was observed: some specimens were penetrated (P), some cracked (F) and some visually remained virtually intact (NP), that is, they were not penetrated. The results of the low velocity impact tests indicate that high temperatures affect polypropylene significantly and practically eliminate the effect of nanoclay reinforcement. As a consequence the specimens show ductile behavior and were not penetrated. However, at room and low temperatures the effect of nanoclay reinforcement is discernable and addition of nanoclay makes the specimens more brittle, resulting in penetration of most of them.
Teaching Kinematics and Kinetics From a Project-Based Experience Analyzing Sci-Fi Motion Pictures: A Star Trek Example
Authors: Kobus C. J. , Chang Y. P.
Published: October 2013

In engineering subjects both simple and complex, retention is an issue. Interested students appear to excel in such subjects, but the retention rates for everyone else suffer somewhat. In this paper an example is laid out of how to utilize motion pictures, and specifically the scientific errors therein, to create interesting problems that this author has found helps in student retention of complex engineering material. Why linking elements of entertainment aids in retention is due to creating emotionally arousing stimuli that enhances memory for central details, as has been shown in neurological studies. The example here focuses on dynamics in general, and calculating kinematic and kinetic elements in particular. The problem from motion pictures is both interesting and complex enough to engage students in a meaningful experience where engineering tools are utilized.
Direct Measurement of the Local Current Density Under Land-Channel Areas With Partially-Catalyzed MEAs
Authors: Jia Shan , Liu Hongtan
Published: October 2013

In a PEM fuel cell, local current density can vary drastically under the land and channel areas. The non-uniform current density distribution not only affects the overall performance of the fuel cell, but also leads to the local temperature and concentration differentiation on the MEA, which can cause problems such as membrane dehydration and catalyst degradations at certain locations. In order to investigate the local current performance, the objective of this work is to directly measure the local current density variations across the land and channel at the cathode in a PEM fuel cell with partially-catalyzed MEAs.

First, the cathode flow plate is specially designed with a single-serpentine channel structure, and the gas diffusion electrode at cathode side is cut to fit this flow field size (5.0cm×1.3cm). Then five different partially-catalyzed MEAs with 1mm width corresponding to different locations from the middle of the gas channel to the middle of the land area are made. Fuel cells with each of the partially-catalyzed MEAs have been tested and the results provide the lateral current density distribution across the channel and the land areas. In the high cell voltage region, local current density is highest under the center of the land area and decreases toward the center of the channel area; while in the low cell voltage region local current density is highest under the middle of the channel area and decrease toward the center of the land area. Different flow rates are tested at the cathode side of the cell to study their effects on the local current density performance along the land-channel direction. And the results show that the flow rate barely has the effect on the current at the high cell voltage region, while it plays a significant role at the low voltage region due to the mass transport effect.
Predictions of the Periodic Response of a Single-Degree-of-Freedom Foam-Mass System by Using Incremental Harmonic Balance
Authors: Azizi Yousof , Davies Patricia , Bajaj Anil K.
Published: October 2013

Vehicle occupants are exposed to low frequency vibration that can cause fatigue, lower back pain, spine injuries. Therefore, understanding the behavior of a seat-occupant system is important in order to minimize these undesirable vibrations. The properties of seating foam affect the response of the occupant, so there is a need for good models of seat-occupant systems through which the effects of foam properties on the dynamic response can be directly evaluated. In order to understand the role of flexible polyurethane foam in characterizing the complex seat-occupant system behavior better, the response of a single-degree-of-freedom foam-mass system, which is the simplest model representing a seat-occupant system, is studied. The incremental harmonic balance method is used to determine the steady-state behavior of the foam-mass system subjected to sinusoidal base excitation. This method is used to reduce the time required to generate the steady-state response at the driving frequency and at harmonics of the driving frequency from that required when using direct time-integration of the governing equations to determine the steady state response. Using this method, the effects of different viscoelastic models, riding masses, base excitation levels and damping coefficients on the response are investigated.
Thermal Analysis of Cancerous Breast Model
Authors: Chanmugam Arjun , Hatwar Rajeev , Herman Cila
Published: October 2013

Breast cancer is one of the most common and dangerous cancers. Subsurface breast cancer lesions generate more heat and have increased blood supply when compared to healthy tissue, and this temperature rise is mirrored in the skin surface temperature. The rise in temperature on the skin surface, caused by the cancerous lesion, can be measured noninvasively using infrared thermography, which can be used as a diagnostic tool to detect the presence of a lesion. However, its diagnostic ability is limited when image interpretation relies on qualitative principles. In this study, we present a quantitative thermal analysis of breast cancer using a 3D computational model of the breast. The COMSOL FEM software was used to carry out the analysis. The effect of various parameters (tumor size, location, metabolic heat generation and blood perfusion rate) on the surface temperature distribution (which can be measured with infrared thermography) has been analyzed. Key defining features of the surface temperature profile have been identified, which can be used to estimate the size and location of the tumor based on (measured) surface temperature data. In addition, we employed a dynamic cooling process, to analyze surface temperature distributions during cooling and thermal recovery as a function of time. In this study, the effect of the cooling temperature on the enhancement of the temperature differences between normal tissue and cancerous lesions is evaluated. This study demonstrates that a quantification of temperature distributions by computational modeling, combined with thermographic imaging and dynamic cooling can be an important tool in the early detection of breast cancer.
Effect of Nonideal Solution Behavior on Desalination of a Sodium Chloride (NaCl) Solution and Comparison to Seawater
Authors: Mistry Karan H. , Lienhard John H.
Published: October 2013

Proper evaluation of the Gibbs free energy and other properties of seawater and other aqueous solutions is essential in the analysis of desalination systems. Standard seawater has been studied extensively and property data are readily accessible. However, many aqueous solutions requiring desalination have significantly different composition from seawater and seawater data is generally not accurate for these solutions. Experimental data for a given aqueous solution may be unavailable under the conditions of interest. Therefore, there is a need to model relevant physical properties from chemical thermodynamic principles. In particular, for solutions that are not ideal, the activity and fugacity coefficients must be considered. In this paper, the effect of nonidealities in sodium chloride (NaCl) solutions is considered through a parametric study of the least work of separation for a desalination system. This study is used to determine the conditions under which the ideal solution approximation is valid and also to determine when an NaCl solution is a good approximation to standard seawater. It is found that the ideal solution approximation is reasonable within ranges of salinities and recovery ratios typical of those found in the seawater desalination industry because many of the nonidealities cancel out, but not because the solution behaves ideally. Additionally, it is found that NaCl solutions closely approximate natural seawater only at salinities typically found in seawater and not for salinities found in typical brackish waters.
Experimental Validation of Temperature Distributions Across a Heat Exchanger for a Thermoelectric Generator
Authors: Dove Megan , Pandit Jaideep , Ekkad Srinath , Huxtable Scott
Published: October 2013

Thermoelectric generators (TEGs) are currently a topic of interest in the field of energy harvesting for automobiles. In applying TEGs to the outside of the exhaust tailpipe of a vehicle, the difference in temperature between the hot exhaust gases and the automobile coolant can be used to generate a small amount of electrical power to be used in the vehicle. The amount of power is anticipated to be a few hundred watts based on the temperatures expected and the properties of the materials for the TEG. This study focuses on developing efficient heat exchanger modules in order to maximize the power generation for a given vehicle and TEG. A computational fluid dynamics (CFD) model run by the authors has provided performance predictions for various cases on the cooling side of the heat exchanger. This paper discusses the setup and results of the experimental validation for the CFD model for the proposed TEG heat exchanger module.
Exergetic Analysis of an Air Conditioning System by Absorption for Transport Vehicles
Authors: Almeida Antonio Gabriel S. , dos Santos Arthur B. , Torres Ednildo Andrade
Published: October 2013

A traditional vehicular air conditioning system using vapor compression increases fuel consumption by at least 15%, while provoking a reduction in engine power. Whereas an internal combustion engine converts about 30% of the energy into mechanical energy, about 35% is released in the form of exhaust gas and 25% is dissipated through the cooling system, and approximately 50% of the available fuel energy is released as heat to the environment. This heat could be used by an absorption refrigeration system, which requires a high temperature source to provide the vaporization of the refrigerant and decoupling from the absorbent solution.

The main objective of this paper is to present a thermodynamic evaluation of the use of heat recovery in internal combustion engines, Diesel cycle, to drive an air conditioning absorption refrigerator for vehicles using the pair water-ammonia. An energy and exergy analysis, applying the First and Second Law of Thermodynamics to the systems involved, is developed in a simulator to evaluate the technical feasibility of using this system to weatherize large vehicles. It identifies the points of the system where the highest irreversibility is found, thus enabling the power focused on reducing such losses. By using asimulation, we hope to determine the basis for the assembly of a prototype vehicular air conditioning system by absorption in transport vehicles.
Flow Boiling Characteristics of Dilute Emulsion in Microchannel
Authors: Morshed A. K. M. M. , Paul Titan C. , Fang Ruixian , Khan Jamil A.
Published: October 2013

Effect of dispersed low boiling point liquid on flow boiling performance of DI water in a microchannel has been investigated experimentally. Experiments were carried out in a single microchannel having hydraulic diameter 672 μm and also in a parallel microchannel having hydraulic diameter of each channel 500 μm. Emulsion was prepared by dispersing FC-72 in de-ionized (DI) water. Both single-phase and two-phase convective heat transfer experiments were performed at different flow rates for different volume fraction of the dispersing liquid. Results from the pure DI water were used as the base line data. It was found that presence of the dispersed low boiling point liquid doesn’t show any significant effect in two-phase convective flow, whereas in single-phase region HTC decreases marginally. Temperature gradient present along the axial direction of the microchannel was observed to reduce for the emulsion compared to the pure DI water.
Sequential Perturbation Uncertainty Propagation in Thermal-Fluid Applications
Authors: Manteufel Randall D.
Published: October 2013

A challenge in an undergraduate mechanical engineering curriculum is having students demonstrate “an ability to design and conduct experiments, as well as analyze and interpret data” as required for ABET accreditation. It is expected that students be able to identify and quantify sources of uncertainty, propagate uncertainties to intermediate and final results, interpret the relative importance of uncertainty sources, and develop experimental strategies to reduce the uncertainties in the final results. A spreadsheet application is presented that helps students learn these concepts and “see” what drives the uncertainty in the final results. The method known as sequential perturbation is used and shown to greatly reduce the tediousness of the calculations. As presented, the method significantly reduces the complexity of uncertainty analysis by eliminating the need to differentiate relationships between primary measurements and inferred measurements. Differentiation of complex relationships is often tedious and error-prone. The method is applied to three thermal-fluid application problems. Feedback from students is presented and is positive. The method summarized here should help students learn about the propagation of uncertainties and help demonstrate meeting ABET outcome “b”. The method can be extended beyond laboratory classes and is shown to be useful in design of experiments.
Domestic Hot Water Storage Tank: Design and Analysis for Improving Thermal Stratification
Authors: Devore Nathan , Yip Henry , Rhee Jinny
Published: October 2013

Experimental designs for a solar domestic hot water storage system were built in efforts to maximize thermal stratification within the tank. A stratified thermal store has been shown by prior literature to maximize temperature of the hot water drawn from the tank while simultaneously increasing the temperature delta required for effective heat transfer from the solar panels, thereby improving the annual performance of domestic solar hot water heating systems (DSHWH) by 30%–60%. Our design incorporates partitions, thermal diodes, and a coiled heat exchanger enclosed in an annulus. The thermal diodes are passive devices that promote natural convection currents of hot water upwards, while inhibiting reverse flow and mixing. Several variations of heat exchanger coils, diodes and partitions were simulated using ANSYS Computational Fluid Dynamics, and benchmarked using experimental data. The results revealed that the optimum design incorporated two partitions separated by a specific distance with four diodes for each partition. In addition, it was discovered that varying the length and diameter of the thermal diodes greatly affected the temperature distribution. The thermal diodes and partitions were used to maintain stratification for long periods of time by facilitating natural convective currents and taking advantage of the buoyancy effect. The results of the experiment and simulations proved that incorporating these elements into the design can greatly improve the thermal performance and temperature stratification of a domestic hot water storage tank.
Silicon Carbide Solar Receiver for Residential Scale Concentrated Solar Power
Authors: Neber Matthew , Lee Hohyun
Published: October 2013

The benefits of Concentrated Solar Power (CSP) systems include the ability to use them in combined cycles such as Combined Cooling Heat and Power (CCHP), and direct AC power generation. While this is done with success for utility scale power production, there are currently no systems offering this for residential scale, distributable power systems. In prior research, a low-cost high-temperature cavity receiver for a wide variety of applications was developed by employing silicon carbide [1]. The proposed design takes advantage of exclusive manufacturing techniques for ceramics such as machining in the green state and sintering multiple simple parts together to form a single complex part. Serious consideration has gone into designing a receiver that will be universally compatible with a number of applications. Some applications include using the receiver in a combined cycle power generation, as a chemical reactor, or for combined heat and power. The focus of this research is to analyze system metrics for a CCHP dish-Brayton system that is feasible for residential scale use. Preliminary research shows that an adequately sized system could provide a single family home with 2.5 kW of electricity and another 7 kW of process heating that could be used for absorption chilling or hot water and space heating. Cost analysis on the system will be performed to quantify its economic viability. Results on the analysis for multiple process heating applications will be presented along with the proposed design.
Flow Control Using Alternating Magnetic Fields During Crystal Growth From a Melt
Authors: Huang Yue , Davis Kenneth E. , Houchens Brent C.
Published: October 2013

Flow control during bulk melt crystal growth is desirable for producing ternary alloy semiconductors with tunable lattice parameters and bandgap energy, providing custom materials for specific electro-optical applications. Segregation between constituent elements in the melt, be it through preferential rejection at the growth front or density variations, limits the growth rate and the uniformity in the crystal. External alternating magnetic fields are employed to stir the electrically conducting melt. While mixing is desired, turbulent flow is generally not. Precise control is required to maintain a laminar melt flow while providing sufficient mixing. Stirring via a rotating magnetic field (RMF) and a three-coil traveling magnetic field (TMF) is modeled and compared for a cylindrical melt confined in an ampule. The RMF imposes a body force in the azimuthal direction while the TMF induces primarily radial and axial body forces. The magnetic fields are effectively decoupled from the flow fields due to the small magnetic Reynolds number. Therefore, the magnetic fields are first determined using a finite element solver. The flows are then solved by a spectral element model of the Navier-Stokes equations including an electromagnetic body force term.
Toward Clinically Applicable Steady-Hand Eye Robot for Vitreoretinal Surgery
Authors: He Xingchi , Roppenecker Daniel , Gierlach Dominikus , Balicki Marcin , Olds Kevin , Gehlbach Peter , Handa James , Taylor Russell , Iordachita Iulian
Published: October 2013

This paper reports new developments and optimizations for clinical use of the Steady-Hand Eye Robot for vitreoretinal surgery. Vitreoretinal surgery requires precise micro-manipulation of delicate tissues. Surgical performance is limited by physiological hand tremor, fatigue, poor kinesthetic feedback, as well as patient movement. The previously developed Steady-Hand Eye Robot has been extensively used in in vivo experiments. Several safety and ergonomic limitations observed in the in vivo environment serve as motivation for a novel robot wrist design. The new robot wrist consists of a symmetric remote center of motion (RCM) tilt mechanism and a slim tool holder with a quick release mechanism for the surgical instruments. The RCM tilt mechanism provides a tilt motion range of ±45° and a stiffness of 21 N/mm. Two different release force thresholds for the quick release mechanism were designed. The soft configuration requires 2–3 N to retract the surgical instruments while the hard configuration requires 5–6 N.
Evaluation of CFD Simulations of Film Cooling Performance in the Showerhead Region of a Turbine Vane Including Conjugate Effects
Authors: Dyson Thomas E. , Bogard David G. , Bradshaw Sean D.
Published: October 2013

Computational simulations using RANS and the k-ω SST turbulence model were performed to complement experimental measurements of overall cooling effectiveness and adiabatic film effectiveness for a film cooled turbine vane airfoil. Particular attention was placed on the showerhead. The design made use of five rows of showerhead holes and a single gill row on both pressure and suction sides. The simulated geometry also included the internal impingement cooling configuration. Internal and external boundary conditions were matched to experiments using the same vane model. To correctly simulate conjugate heat transfer effects, the experimental vane model was constructed to match the Biot number for engine conditions. Computational predictions of the overall and adiabatic effectiveness were compared to experimental measurements from both the conducting vane and a model constructed from low conductivity foam. The results show that the k-ω SST RANS model over-predicts both adiabatic and overall effectiveness due in part to limited jet diffusion. The simulations were also used to investigate heat transfer augmentation, which is difficult to measure experimentally in the showerhead region. The results showed substantial augmentation of 1.5 or more over large portions of the leading edge, with many areas exceeding 2.0. However, the simulations also showed a reduction in heat transfer (i.e., hf/h0 < 1) for locations beneath the coolant jets. This result was likely due to Taw being an inappropriate driving temperature for separated jets.
Failure Mode Transition During Delamination of Thick Unidirectional L-Shaped Composite Laminates
Authors: Yavas Denizhan , Gozluklu Burak , Coker Demirkan
Published: October 2013

Curved composite laminates such as L-beams are frequently used in wind turbine blade structures such as spars and ribs. It is widely assumed that delamination initiates at the curved region of the L-shaped laminate leading to loss of loading carrying capacity. However, as shown in this paper, under certain conditions a second failure mode in thick L-shaped laminates is observed in which a secondary crack initiates at the arm region. Delamination in L-shaped laminates is modeled using a sequential analysis with implicit analysis followed by explicit dynamic (explicit) finite element analysis in conjunction with cohesive zone methods. The 2-D model consists of 24 plies of unidirectional CFRP laminate with an initial crack at the center of curved region. Loading is applied parallel to one arm quasi-statically and the observed delamination occurs dynamically. For thin laminates and larger precracks, delamination starts from the initial crack and propagates towards the arms. For thicker L-shaped laminates and smaller precracks at the center of curved region, formation of secondary crack in the arm region is observed. Therefore the size of the initial crack as a function of thickness at the center of the curved region mainly decides the failure mode.
Modeling of Micro Electron Beam Welding With Melting and Evaporation
Authors: Gajapath Satya S. , Mitra Sushanta K. , Mendez Patricio F.
Published: October 2013

Integrating the components at micro and nano levels is becoming a challenge as the demand to scale the devices further down grows, especially in the micro-electronics and medical industry. The current use of microwelding technology using laser and electron beams suffers from a major set back of excessive surface ablation. The present paper proposes using electron beam as a volume heating source to avoid surface ablation and arrives at the conditions to micro-weld successfully through numerical analysis.
Investigation of the Effects of Flame Holder on the Combustion Characteristics of a Flat Flame Micro Combustor
Authors: Turkeli-Ramadan Zerrin , Sharma Rajnish N. , Raine Robert R.
Published: October 2013

Different flame holder materials and geometric parameters (pore size, thickness etc.) were experimentally tested in terms of pressure loss and combustion characteristics for the micro combustor of the ultra micro gas turbine (UMGT). Alumina ceramic porous plates, sintered stainless steel and perforated plates were used as flame holders within a 46 mm quartz walled micro combustor. The range of the average pore size of the porous plates and the sintered stainless steel plates are between 100 μm to 580 μm with an average porosity of 43∼54% and thickness of 1 mm to 4 mm. The perforated plate had a hole diameter of 1 mm and the distance between the centres of the holes was 2 mm. It was observed that the pore size and the thickness affect the pressure loss. However, at low incoming flow velocities all the flame holders had pressure losses of less than 5%. Flat flame combustion was achieved with all the different flame holders, but it stabilized at different incoming velocities and air to fuel ratios, according to different flame holder material and geometric parameters.
Evaluation of Pulse Jet Mixer Concentration Profiles to Track Slurry Suspension
Authors: Bamberger Judith Ann
Published: October 2013

A series of tests were conducted to evaluate the mixing performance of pulse jet mixers. A pulse-jet mixing system involves an array of pulse tubes with nozzles directed toward the vessel floor inside the mixing vessel. Fluid is expelled from the pulse tubes during the drive portion of the PJM cycle. Fluid refills into the pulse tubes during the refill portion of the PJM cycle. This cyclical process can be used to mix slurries.

Concentration profiles as a function of location and elevation in the tank were taken during the pulse jet mixer cycle at several radial locations within the mixing vessel: at the center, near the wall, and half-way between the center and the wall. The data are being examined to determine how the time during the cycle affects the solids suspension and settling. Examples will be presented for several particle types, concentrations, and pulse-jet operating conditions.
Development of a Toolkit for the Analysis and Design of Composite Pressure Vessels
Authors: Ledesma Elias , Aceves Salvador M. , Espinoza-Loza Francisco , Ravani Bahram
Published: October 2013

This work presents the development of a toolkit for the analysis and design of composite pressure vessels. The toolkit is developed in APDL (ANSYS parametric design language) to work inside ANSYS. In addition to the macros in APDL, a graphical user interface is developed in Tk/Tcl to access the toolkit. The toolkit includes a tool for composite material analysis with the method of cells, developed and implemented to get laminae properties from fiber and matrix properties. A shell elements tool and a hexahedral elements tool were implemented to generate 3D type 3 (metal lined) or type 4 (plastic lined) fiber reinforced pressure vessel models. A mixed Tsai-Wu and maximum stress tool was also implemented in the toolkit to predict composite failure. In addition to these tools, there are two scripts to model honeycomb as well as an algorithm to perform a netting analysis.
Turning of SAE 1050 Steel With Vegetable Base Cutting Fluid
Authors: da Silva Rosemar Batista , Machado Álisson Rocha , de Oliveira Almeida Déborah , Ezugwu Emmanuel O.
Published: October 2013

The study of cutting fluid performance in turning is of great importance because its optimization characteristics has associated benefits such as improved tool life and overall quality of machined components as well as reduction in power consumption during machining. However, there are recent concerns with the use of cutting fluids from the environmental and health standpoints. Since environmental legislation has become more rigorous, the option for “green machining” attracts the interest of several manufacturing companies. It is important to consider the cost of machining which is associated with tool wear, depending on the cutting environment. The use of vegetable oil may be an interesting alternative to minimize the health and environmental problems associated with cutting fluids without compromising machining performance. This paper presents a comparative study of mineral and vegetable cutting fluids in terms of tool wear after turning SAE 1050 steel grade with cemented carbide cutting tools. Constant depth of cut of 2mm and variable cutting speed (200 and 350 m/min) and feed rate (0.20 and 0.32 mm/rev) were employed. Test results suggest that is possible to achieve improvement in machinability of the material and increase tool life by using vegetable cutting fluid during machining. Tool life increased by about 85% when machining with vegetable-based fluids compared to mineral-based fluids. Analysis of the worn tools, however, revealed a more uniform wear on the worn flank face when machining with mineral-based fluids.
A High-Precision Control System Used for Optical Efficiency Measurements of Parabolic Trough Collectors at NREL
Authors: Zhu Guangdong , Netter Judy , Gray Allison
Published: October 2013

The testing facility called the Outdoor Collector Test Loop (OCTL), which is located at the Solar Industrial Mesa Top Area (SIMTA) of National Renewable Energy Lab (NREL), measures the optical efficiency of parabolic trough collectors. It uses a dual-axis, large-payload solar tracker to hold a parabolic trough collector module and track the sun. Due to the growing need for measurement accuracy and efficiency, a new tracking control system for the tracker has been acquired and successfully commissioned as of February 2012. As part of the customization needed to address the unique testing requirements at the OCTL, new tracking modes have been designed and embedded into the new controller. In particular, the incidence angle modifier (IAM) and fixed-azimuth modes allows the OCTL to readily measure the IAM values for a trough collector, significantly improving the speed and efficiency of IAM data collection compared to the previous controller (with test times of days versus weeks). The Siemens S7 1200 PLC integrates various hardware components (such as the hydraulic pump, encoders, sun sensor and wind sensor) through corresponding communication channels, and a Simatic HMI panel provides a powerful user-friendly interface for operation, monitoring, and diagnostics. In addition, NREL integrated the Siemens tracking control program with the existing LabVIEW program that serves as a user interface of the thermal fluid loop, and calibrated the tracking platform as a whole to characterize its tracking accuracy. At last, the challenges and opportunities for the control system in the area of concentrating solar power (CSP) are briefly discussed.
A Review of the Development of Wind Turbine Generators Across the World
Authors: Goudarzi N. , Zhu W. D.
Published: October 2013

Wind power as a source of green and abundant energy has acquired a great momentum across the world and is proposed as one of the main new world power sources. In the last few decades, wind turbines with different generators have been developed to increase the maximum power capture, minimize the costs, and expand the use of the wind turbines in both onshore and offshore applications. This paper studies the development of different types of wind turbine generator technologies and discusses the advantages and disadvantages of each type. In addition, a comparison of different generator designs based on the technical data and market trends is provided. To better understand the development of generator concepts on the market, the market trends of current large generators with a capacity of 2.5 MW and above across the world are evaluated.
High Speed Routing of Woven Carbon Fiber Reinforced Epoxy Laminates
Authors: Meshreki M. , Sadek A. , Attia M. H.
Published: October 2013

Little is known about the high speed routing of Carbon Fiber Reinforced Polymers (CFRP). Most of the work in the literature has focused on the drilling of CFRP. In this paper, an extensive experimental study has been conducted to better understand the dynamic, tribological, and thermal characteristics of high speed milling of CFRPs, in the range of 10,000 to 40,000 rpm (200 to 800 m/min, for 6.35 mm end-mill). The material used was a quasi-isotropic laminate comprising 35 plies of woven graphite epoxy. The tool wear was investigated on the flank and the rake faces. The machined slots were characterized in terms of straightness errors, dimensional errors, surface roughness, and delamination. The tool over-hang controls the tool dynamics, in this high speed range, and significantly affect various quality attributes of the produced holes; roughness, dimensional errors, and straightness. Similar trends were observed for the forces and the temperatures, whereby there is a given speed at which they reach a minimum and then they start to increase for higher speeds. The machining force and temperature trends with varying speeds and feeds are controlled by the chip load, the specific cutting pressures, and the effect of the frictional forces. The increased tool wear was found to directly affect the cutting forces and consequently lead to high delamination and surface roughness. The milled surface quality was mainly controlled by the feed rate. Limited surface delamination was observed due to the low axial forces associated with the routing process.
Development of a Smart Tire System and its Use in Improving the Performance of a Collision Mitigation Braking System
Authors: Singh Kanwar Bharat , Arat Mustafa Ali , Taheri Saied
Published: October 2013

At present, the commercially available tire monitoring systems are not equipped to sense and transmit high speed dynamic variables used for real-time active safety control systems. Hence, today’s vehicle control systems are limited by the lack of knowledge of critical tire-road states (i.e. the kinematic conditions of the tire to its dynamic properties). From aforementioned discussion, it is clear that some method of estimating tire-road contact parameters would be greatly desirable. Existing tire-road friction estimation approaches often require certain levels of vehicle longitudinal and/or lateral motion to satisfy the persistence of excitation condition for reliable estimations. Such excitations may undesirably interfere with vehicle motion controls. This paper presents a novel development and implementation of a real-time tire-road contact parameter estimation methodology using acceleration signals from a smart tire. The proposed method characterizes the terrain using the measured frequency response of the tire vibrations and provides the capability to estimate the tire road friction coefficient under extremely lower levels of force utilization. Under higher levels of force excitation (high slip conditions), the increased vibration levels due to the stick/slip phenomenon linked to the tread block vibration modes make the proposed tire vibrations based method unsuitable. Therefore for high slip conditions, a tire-road friction model-based parameter estimation approach is proposed. Hence an integrated approach using the smart tire based friction estimator and the model based estimator gives us the capability to reliably estimate friction for a wider range of excitations. Considering the strong interdependence between the operating road surface condition and the instantaneous forces and moments generated; this real time estimate of the tire-road friction coefficient is expected to play a pivotal role in improving the performance of a number of vehicle control systems. In particular, this paper focuses on the possibility of enhancing the performance of collision mitigation braking systems.
Mechanics of Buckled Structure MEMS for Actuation and Energy Harvesting Applications
Authors: Porter Daniel A. , Gowrishetty Usha R. , Phelps Isaac J. , Walsh Kevin M. , Berfield Thomas A.
Published: October 2013

Buckled structures offer many great benefits to microelectromechanical systems (MEMS), using naturally occurring residual stresses to provide structures with switchable stable states capable of large transverse deflections. In this work a simple, circular bi-layer diaphragm style of buckled MEMS devices is discussed. The buckling behavior of the system, including buckling height and switching criteria, is modeled and analyzed in ANSYS, then compared with theoretical equations and experimental measurements. Results of this work will help to yield optimal design parameters for both energy harvesting and actuation MEMS applications.
Experimental Study of Enhanced Steam Generation Through Electrolysis in Glow Discharge Mode
Authors: Sharma Neeraj , Diaz Gerardo , Leal-Quiros Edbertho
Published: October 2013

Electric discharges through liquids initiate various chemical and physical processes which can be utilized in efficient treatment of waste water and generation of steam. In the present paper, generation of heat in an electrolytic cell operating in glow discharge mode has been studied. It is observed that glow discharge mode constitutes an efficient process for steam generation.

The electric current between the electrodes reduces dramatically in the glow discharge mode and the voltage between the electrodes increases to open circuit voltage. The decrease in current can be explained by decrease in overall electrical conductivity of the system with the formation of a vapor film around the cathode. This vapor film is partially ionized because of the presence of locally high electric field near the cathode. It is this ionization process that results in a visible glow around the cathode and an increased rate of volumetric heat generation.
Parameter Estimation of a Rotating Beam Under a Kalman Filtering Framework
Authors: Atmeh Ghassan M. , Hasan Zeaid
Published: October 2013

The current study presents the problem of state and parameter estimation of flexible structures under a Kalman filtering framework. Inspired from a previous publication by the authors, the work presented here tackles the issue of practically acquiring the natural frequency of a flexible structure for structural health monitoring purposes. The Kalman filter theory is introduced where the linear Kalman filter and the unscnted Kalman filter algorithms are explained. An example of estimating the dynamics of a simply supported beam, modeled using the finite element method, is first discussed for the purpose of establishing the effectiveness of the Kalman filtering approach in dynamic structural systems. A more complicated system consisting of a flexible appendage attached at one end to a rotating hub is then introduced. The system dynamics are modeled using the finite element method, which is incorporated in a computer simulation where the Kalman filter is applied to estimate not only the appendage dynamics, but its parameters as well; specifically its natural frequency. The purpose of the work is to establish a practical method of acquiring the natural frequency for a flexible structure to accommodate a structural health monitoring system. Results show that the Kalman filter is a viable option for estimating the natural frequency of flexible structure.
Acoustic and Vibration Responses of Lexan Plate Constructions
Authors: Al-Zubi Mohammad , Ayorinde Emmanuel , Dundar Akif , Witus Gary
Published: October 2013

Lexan, a commercial form of polycarbonate resin thermoplastic, has some acoustic and vibration damping capabilities, among other properties, which have recommended it for building, vehicle and appliance constructions. However, along the lines of intelligently designed periodic-structure materials, with more recent understanding, these capabilities can be enhanced in different ways, but there has not been a systematic exploration of this process. Such could be useful in the consideration of possible meta-material applications of lexan constructions. This paper makes a report on work in which some construction patterns of lexan structures are tested. Deductions are made from the results in order to aid in the beneficial design of such structures for vibration and acoustic containment.
Modern Challenges in Converting a Traditional Engineering Class Into a Fully Online Course
Authors: McCaslin Sara , Brown Fredericka
Published: October 2013

The demand for engineering courses in online format is growing for both undergraduate and graduate level coursework. Because of the abundance of software tools available for creating virtual learning environments, online courses are rapidly evolving past the posting of hour-long lectures in video format to lecture notes that are interactive, instant self-assessment feedback, and teaching modules that are fully ADA compliant. This paper explores the challenges faced by faculty members in creating a fully online course that can effectively present challenging, engaging material that solidly focuses on student learning objectives and provides authentic assessment of those same objectives.
Development of the New Drafting and Computer Aided Design Standards for Mechanical Engineering Program
Authors: Joo Sung-Hwan
Published: October 2013

The paper provides the method to develop the drafting and CAD standards for mechanical engineering program based on the systemic approach.

The drafting has been used since the early stage of engineering. Lots of drafting technique has been developed and standardized. Recently, Computer Aided Design (CAD) software has been used widely in academia and industries too. Because of these reasons, every mechanical engineering program offers Drafting and CAD courses to its students. Some programs even have their own Drafting and CAD standards. However, it is not easy to develop the Drafting and CAD standard for whole program. It needs a careful plan to develop the standards. It needs to meet the certain requirements. Those requirements are 1) It needs to meet ASME Y14/ANSI Y14 standard as much as possible, 2) Students should be able to understand the standards and apply the rules to their own drawing and CAD models, 3) Any instructors should be able to give the proper feedback to students about their drawing using the standards, 4) Graduating students should be able to adopt the standard of their company easily.

To meet these requirements, some preliminary work must be done. 1) Understanding of ASME Y14 is needed, 2) Expertise of one or more CAD software packages is required, 3) Students’ level of understanding the ASME Y14 standards needs to be measured, 4) Feedback from industries is required. Each steps of development of Drafting and CAD standards are explained using real example of students work.