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Articles 151 - 180 of 253

Full-Text Articles in Mechanical Engineering

Numerical Simulation Model On Irreversibility Of Shock-Wave Process, Longhao Huang Oct 2013

Numerical Simulation Model On Irreversibility Of Shock-Wave Process, Longhao Huang

Master's Theses (2009 -)

The objective of this research is to develop a better understanding of the irreversibilities associated with the shock compaction of matter, especially as a result of impact. Due to complex shock processes, experimentation alone cannot fix the material state, since properties such as internal energy, entropy as well as the shock process are not measurable. Thus, in addition to experimentation, analytical and numerical methods are also used to completely characterize the shock process, although they are restricted by underlying constitutive assumptions. Instead of using artificial irreversibility, such as artificial viscosity to simplify and stabilize the numeric shock model, this work …


An Investigation Of Phase-Change Effects During Rapid Compression Machine Experiments, Colin Banyon Oct 2013

An Investigation Of Phase-Change Effects During Rapid Compression Machine Experiments, Colin Banyon

Master's Theses (2009 -)

Rapid compression machines (RCMs) are well characterized laboratory scale devices capable of achieving internal combustion (IC) engine relevant thermodynamic environments. These machines are often used to collect ignition delay times as targets for gas-phase chemical kinetic fuel autoigntion models. Modern RCMs utilize creviced piston(s) to improve charge homogeneity and allow for an adequate validation of detailed chemistry mechanisms against experiments using computationally efficient, homogeneous reactor models (HRMs). Conventionally, experiments are preformed by introducing a premixed gas of fuel + oxidizer + diluent into the machine, which is compressed volumetrically via a piston. Experiments investigating low-vapor pressure fuels (e.g. diesels, biodiesels, …


Admittance Selection For Force Guided Assembly With Optimal Motion, Fernando Rodriguez Anton Oct 2013

Admittance Selection For Force Guided Assembly With Optimal Motion, Fernando Rodriguez Anton

Master's Theses (2009 -)

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Current robots lack the precise relative positioning necessary to complete automatic assembly tasks. Several solutions have been proposed. Some approaches use complex vision and force sensing systems to generate corrective motion if misalignment is present in the assembly task. Other solutions rely on generating elastic behavior, known as compliance, between the end eector and the held movable part. This compliant mechanism helps guide the movable part of the assembly into its proper position. The project focuses on designing a process by which passive compliant systems can achieve successful assembly for a range of misalignment and generate error-reducing motion that …


Theoretical Analysis Of Torsionally Vibrating Microcantilevers For Chemical Sensor Applications In Viscous Liquids, Tao Cai Oct 2013

Theoretical Analysis Of Torsionally Vibrating Microcantilevers For Chemical Sensor Applications In Viscous Liquids, Tao Cai

Dissertations (1934 -)

Dynamically driven microcantilevers excited in the transverse (or out-of-plane) direction are widely used as highly sensitive chemical sensing platforms in various applications. While these devices work very well in air, their performance in liquids is not efficient because of the combination of increased viscous damping and effective fluid mass. In order to improve the characteristics of microcantilevers in liquid environments, some other vibration modes such as the torsional mode and lateral (or in-plane) flexural mode have been proposed.
In this work, the characteristics of torsionally vibrating rectangular microcantilevers with length L, width b and thickness h in viscous liquids are …


Profile Synthesis Of Planar Variable Joints, Brian James Slaboch Sep 2013

Profile Synthesis Of Planar Variable Joints, Brian James Slaboch

Dissertations (1934 -)

Reconfigurable mechanisms provide quick changeover and reduced costs for low volume manufacturing applications. In addition, these mechanisms provide added flexibility in the context of a constrained environment. A subset of planar reconfigurable mechanisms use variable joints to provide this added adaptability.

In this dissertation, the profile synthesis of planar variable joints that change from a rotational motion to a translational motion was investigated. A method was developed to perform automated profile synthesis. It was shown that combinations of higher variable joints can be used to create kinematically equivalent variable joints that are geometrically different.

The results were used to create …


A Multi-Scale Approach To A Greater Understanding Of The Behavior Of Heterogeneous Materials Under Dynamic Loading, Andrew J. Van Vooren Jul 2013

A Multi-Scale Approach To A Greater Understanding Of The Behavior Of Heterogeneous Materials Under Dynamic Loading, Andrew J. Van Vooren

Master's Theses (2009 -)

The penetration of granular materials is of interest to a variety of different fields, and is an active area of research. The objective of this project is to gain understanding of the dynamics of a projectile penetrating into a granular material. To do this, experiments were run and a numerical model was created.

A dart gun was used to accelerate an aluminum dart to velocities around 100 m/s, which then impacted a target tank filled with Ottawa sand. The dart flew along a view window, which allowed for a recording of the penetration event using a high speed camera. Pressure …


Dynamic Modeling Of A Belt Driven Electromechanical Xy Plotter Cutter, Joseph V. Prisco Jul 2013

Dynamic Modeling Of A Belt Driven Electromechanical Xy Plotter Cutter, Joseph V. Prisco

Master's Theses (2009 -)

Current industrial XY plotter cutters that use a belt driven gantry for the X motion and media feed for the Y motion sometimes have performance issues in cutting out high quality shapes. Mathematical models for these plotter cutters are not publicly available and thus the parameters critical to cut quality are not well understood. This thesis develops a dynamic, electromechanical model for the gantry arm and media feed using first principles and a non-linear friction model. These models are independently simulated and experimentally verified. In order to verify the effectiveness of the individual models, they are combined with a control …


Flame Temperature Imaging Of A Low Nox Burner Via Laser Rayleigh Scattering, Nicholas A. Smith Jul 2013

Flame Temperature Imaging Of A Low Nox Burner Via Laser Rayleigh Scattering, Nicholas A. Smith

Master's Theses (2009 -)

Federal and global legislation are requiring increasingly stringent emission regulation on household appliances and in particular water heater burners. Emissions like NOx (NO and NO2) are a growing concern due to their adverse health effects and contribution to tropospheric ozone, acid rain, and smog formation. As NOx is more closely controlled, appliance manufacturers are developing low emission burners for use in water heaters.

Flame temperature is strongly correlated to NOx production. Hence, characterizing flame temperatures in new burners is a key part of improving upon burners used today and the development of future burners. Temperature measurements applied to a new, …


Modeling And Testing Of An R-23/R-134a Mixed Refrigerant System For Low Temperature Refrigeration, Nicholas Hugh, Margaret Mathison, Anthony Bowman Jan 2013

Modeling And Testing Of An R-23/R-134a Mixed Refrigerant System For Low Temperature Refrigeration, Nicholas Hugh, Margaret Mathison, Anthony Bowman

Mechanical Engineering Faculty Research and Publications

Low temperature refrigeration storage equipment in the biotechnology industry typically uses cascade refrigeration to achieve evaporating temperatures of -80 °C (-112 °F) or below. Current systems utilize multiple compressors leading to high energy consumption. Equipment operating costs contribute significantly to the total operating costs of biotechnology companies and therefore motivate the development of more efficient alternatives for low temperature refrigeration. This paper describes a single compressor R-23/R-134a mixed refrigerant cycle that has been designed to extract a load of 0.256 kW (873.5 Btu/hr) from a conditioned space at -80 °C (-112 °F). The designed system compresses a mixture of the …


Using Remote Access For Sharing Experiences In A Machine Design Laboratory, Mark L. Nagurka, Fernando Rodriguez Anton, Richard W. Marklin Jr. Jan 2013

Using Remote Access For Sharing Experiences In A Machine Design Laboratory, Mark L. Nagurka, Fernando Rodriguez Anton, Richard W. Marklin Jr.

Mechanical Engineering Faculty Research and Publications

A new Machine Design Laboratory at Marquette University has been created to foster student exploration and promote “hands-on” and “minds-on” learning. Laboratory experiments have been developed to give students practical experiences and expose them to physical hardware, actual tools, and design challenges. Students face a range of real-world tasks: identify and select components, measure parameters (dimensions, speed, force), distinguish between normal and used (worn) components and between proper and abnormal behavior, reverse engineer systems, and justify design choices. The experiments serve to motivate the theory, spark interest, and promote discovery learning in the subject of machine design.

This paper presents …


Equation Of State And Isentropic Releasem Of Aluminum Foam And Fluoropolymer Composites, John Borg, Warren R. Maines, Mike Nixon, Lalit Chhabildas Jan 2013

Equation Of State And Isentropic Releasem Of Aluminum Foam And Fluoropolymer Composites, John Borg, Warren R. Maines, Mike Nixon, Lalit Chhabildas

Mechanical Engineering Faculty Research and Publications

There is considerable interest in developing a better understanding of the dynamic behavior of heterogeneous materials. This study investigates and compares the dynamic response of 20 and 47% dense aluminum foam systems with and without a polytetrafluoroethylene (PTFE or Teflon) fill. Experiments on 47% foam were conduced in a 60 mm bore gun in a reverse ballistic configuration at velocities ranging from 350 m/s to 2.5 km/s. The particle velocity of the backside of the anvil was monitored with a VISAR system. Mesoscale simulations are in good agreement with the available experimental data. Both the experimental and simulated data are …


Aquaponics: A Sustainable Food Production System That Provides Research Projects For Undergraduate Engineering Students, Richard W. Marklin Jr., Margaret Mathison, Brooke K. Mayer, Mark L. Nagurka, Vikram Cariapa, Jay Schabelski Jan 2013

Aquaponics: A Sustainable Food Production System That Provides Research Projects For Undergraduate Engineering Students, Richard W. Marklin Jr., Margaret Mathison, Brooke K. Mayer, Mark L. Nagurka, Vikram Cariapa, Jay Schabelski

Mechanical Engineering Faculty Research and Publications

Aquaponics is a closed-loop, recirculating water system in which plants and fish grow together mutualistically. Aquaponics resembles a natural river or lake basin in which fish waste serves as nutrients for the plants, which in turn clean the water for the fish. Tilapia and salad greens or herbs are common fish and plants grown in an aquaponics system. The external inputs to an aquaponics system are fish food, minimal amount of water, and energy for lighting and heating the water for the fish and plants.

Aquaponics is a sustainable, efficient system to raise fish protein and vegetables for human consumption. …


Improving Student Learning Through Use Of An In-Class Material Processing Design Project, Joseph P. Domblesky, James A. Rice, Jay R. Goldberg, Mark L. Nagurka Jan 2013

Improving Student Learning Through Use Of An In-Class Material Processing Design Project, Joseph P. Domblesky, James A. Rice, Jay R. Goldberg, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

At Marquette University, hybrid project-based learning has been implemented in an undergraduate mechanical engineering course on materials processing and forming using a team-based approach. The goals of the project are to 1) introduce more active and student-centered activities to improve student engagement and mastery of core concepts, 2) increase students' confidence in their ability to apply what they learned in the course to solving real-world problems, 3) enable students to gain experience using engineering software as part of the learning process and in applications context. While use of process modeling software in materials processing and manufacturing courses is not entirely …


Freehand Sketching For Engineers: A Pilot Study, Richard W. Marklin Jr., Jay R. Goldberg, Mark L. Nagurka Jan 2013

Freehand Sketching For Engineers: A Pilot Study, Richard W. Marklin Jr., Jay R. Goldberg, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper describes a pilot study to evaluate Freehand Sketching for Engineers, a one credit, five week course taught to undergraduate engineering students. The short-term goal of this course was to improve engineering students’ freehand sketching ability and to assess their progress with metrics. The long-term objective (desired learning outcome) of this course is to improve the creativity and innovation of student design projects by enhancing students’ ability to visualize their ideas with freehand sketches. The class met two days a week for 75 min per day. Students were taught to draw simple objects such as electrical boxes, with orthographic, …


Analysis Of Laminated Anisotropic Plates And Shells Via A Modified Complementary Energy Principle Approach, Martin Claude Domfang Jan 2013

Analysis Of Laminated Anisotropic Plates And Shells Via A Modified Complementary Energy Principle Approach, Martin Claude Domfang

Dissertations (1934 -)

The present work is concerned with the finite element structural analysis of laminated anisotropic plates and shells. New elements based on a modified complementary energy principle are proposed to improve the analysis of such composite structures. Third order deformation plate and shell models incorporating a convergence parameter are developed to govern the general displacement field.

An eight-node isoparametric quadrilateral element with two independent cross-sectional rotations and three normal displacements is utilized to describe the displacement field. The present modified complementary energy formulation incorporates a number of in-plane strain functions of various orders. The corresponding in-plane stresses for each lamina are …


A Simple Model For The In-Plane Rotational Response Of A Disk Resonator In Liquid: Resonant Frequency, Quality Factor, And Optimal Geometry, Mohomad S. Sotoudegan, Stephen M. Heinrich, Fabien Josse, Nicholas J. Nigro, Isabelle Dufour, Oliver Brand Jan 2013

A Simple Model For The In-Plane Rotational Response Of A Disk Resonator In Liquid: Resonant Frequency, Quality Factor, And Optimal Geometry, Mohomad S. Sotoudegan, Stephen M. Heinrich, Fabien Josse, Nicholas J. Nigro, Isabelle Dufour, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.


Sand Penetration: A Near Nose Investigation Of A Sand Penetration Event, Andrew Van Vooren, John Borg, Joshua Felts Jan 2013

Sand Penetration: A Near Nose Investigation Of A Sand Penetration Event, Andrew Van Vooren, John Borg, Joshua Felts

Mechanical Engineering Faculty Research and Publications

This paper presents experimental and computational results of a long-rod penetrating dry granular sand at velocities near 100 m/s. The objective of this work is to develop a fundamental understanding of the formation and transmission of dynamic force chains, and the motion and fracture of the individual sand grains as the projectile passes. This is accomplished by launching a projectile along a view window, backed by sand, in order to directly view and photograph the projectile/sand interactions. Within the sand system, a two-wave structure was observed, composed of a compaction wave (bow shock) that detaches from the dart and moves …


Discovery Learning Experiments In A New Machine Design Laboratory, Mark L. Nagurka, Fernando Rodriguez Anton Jan 2013

Discovery Learning Experiments In A New Machine Design Laboratory, Mark L. Nagurka, Fernando Rodriguez Anton

Mechanical Engineering Faculty Research and Publications

A new Machine Design Laboratory at Marquette University has been created to foster student exploration with hardware and real-world systems. The Laboratory incorporates areas for teaching and training, and has been designed to promote “hands-on” and “minds-on” learning. It reflects the spirit of transformational learning that is a theme in the College of Engineering.

The goal was to create discovery learning oriented experiments for a required junior-level “Design of Machine Elements” course in mechanical engineering that would give students practical experiences and expose them to physical hardware, actual tools, and real-world design challenges. In the experiments students face a range …


Powered Transtibial Prosthetic Device Control System Design, Implementation And Testing, Jinming Sun Oct 2012

Powered Transtibial Prosthetic Device Control System Design, Implementation And Testing, Jinming Sun

Master's Theses (2009 -)

A powered lower limb prosthesis, which consists of a four bar mechanism, a torsional spring and a brushed DC motor, was previously designed and fabricated. To regulate the motor power input, a two level controller was proposed and built. The control algorithm includes a higher level finite state controller and lower level PID controllers. To implement the control system, a digital signal processor (DSP) control board and MATLAB Simulink were used to realize the higher level control and a DC motor controller was used to realize the lower level PID control. Sensors were selected to provide the required feedback. The …


Enhancing The Engineering Curriculum: Defining Discovery Learning At Marquette University, Jay R. Goldberg, Mark L. Nagurka Oct 2012

Enhancing The Engineering Curriculum: Defining Discovery Learning At Marquette University, Jay R. Goldberg, Mark L. Nagurka

Biomedical Engineering Faculty Research and Publications

This paper summarizes the results of our investigation into the feasibility of increasing the level of discovery learning in the College of Engineering (COE) at Marquette University. We review the education literature, document examples of discovery learning currently practiced in the COE and other schools, and propose a Marquette COE-specific definition of discovery learn-ing. Based on our assessment of the benefits, costs, and tradeoffs associated with increasing the level of discovery learning, we pre-sent several recommendations and identify resources required for implementation. These recommendations may be helpful in enhancing engineering education at other schools.


Mechanism State Matrices For Spatial Reconfigurable Mechanisms, Philip A. Voglewede, Brian Korves, Brian Slaboch Aug 2012

Mechanism State Matrices For Spatial Reconfigurable Mechanisms, Philip A. Voglewede, Brian Korves, Brian Slaboch

Mechanical Engineering Faculty Research and Publications

This paper improves augmented mechanism state matrices by replacing joint code with screw system notation. The proposed substitution allows for a more specific description of the joints in the mechanism and the capability to describe both spatial and planar mechanisms. Examples are provided which elucidate the proposed approach.


Configuration Space Analysis And Synthesis Of Planar Variable Kinematic Joints, Brian Slaboch, Philip A. Voglewede Aug 2012

Configuration Space Analysis And Synthesis Of Planar Variable Kinematic Joints, Brian Slaboch, Philip A. Voglewede

Mechanical Engineering Faculty Research and Publications

No abstract provided.


A Dynamic Model Of A Belt Driven Electromechanical Xy Plotter Cutter, Joseph Prisco, Philip A. Voglewede Aug 2012

A Dynamic Model Of A Belt Driven Electromechanical Xy Plotter Cutter, Joseph Prisco, Philip A. Voglewede

Mechanical Engineering Faculty Research and Publications

No abstract provided.


Controller Design And Preliminary Testing Of A Powered Below-Knee Prosthetic Device, Philip A. Voglewede, Jinming Sun Aug 2012

Controller Design And Preliminary Testing Of A Powered Below-Knee Prosthetic Device, Philip A. Voglewede, Jinming Sun

Mechanical Engineering Faculty Research and Publications

No abstract provided.


Ergonomic Design Of An Aerial Bucket For Ingress And Egress, Bianca M. Bain Jul 2012

Ergonomic Design Of An Aerial Bucket For Ingress And Egress, Bianca M. Bain

Master's Theses (2009 -)

Electric utility companies across the US have been using aerial bucket trucks for line work and troubleshooting for decades. The use of these trucks eliminates the need for workers to climb utility poles in order to repair or maintain lines. Poor ingress and egress design can lead to acute injuries (slips and falls) as well as cumulative injury (musculoskeletal disorders (MSDs)). Utility companies want to know the best combination of steps and handlebars for aerial bucket ingress and egress that would minimize the risk of injury. American National Standards Institute (ANSI) standard – ANSI/SIA A92.2-2009, sets design requirements for aerial …


Are Posture Data From Simulated Tasks Representative Of Field Conditions? Case Study For Overhead Electric Utility Workers, Cristiane Shinohara Moriguichi, Leticia Carnaz, Luiz Carlos De Miranda Jr, Richard W. Marklin, Helenice Jane Cote Gil Coury Jan 2012

Are Posture Data From Simulated Tasks Representative Of Field Conditions? Case Study For Overhead Electric Utility Workers, Cristiane Shinohara Moriguichi, Leticia Carnaz, Luiz Carlos De Miranda Jr, Richard W. Marklin, Helenice Jane Cote Gil Coury

Mechanical Engineering Faculty Research and Publications

Many ergonomics studies are conducted in laboratory-simulated work environments to assess risks for the development of musculoskeletal disorders under more controlled conditions. However, the simulated conditions could be of questionable validity with respect to reproduction of field conditions involving risk factors. The objective of this study was to verify whether the postures recorded for neck extension/flexion and upper arm elevation of overhead electric utility workers in a simulated environment were similar to those recorded in a field environment. Of the three frequently performed tasks analysed, two presented similar exposure in both conditions. However, differences were identified for a more complex …


An In Vitro Comparative Study Of Intracanal Fluid Motion And Wall Shear Stress Induced By Ultrasonic And Polymer Rotary Finishing Files In A Simulated Root Canal Model, Jon Koch, John Borg, Abby Mattson, Kris Olsen, James Bahcall Jan 2012

An In Vitro Comparative Study Of Intracanal Fluid Motion And Wall Shear Stress Induced By Ultrasonic And Polymer Rotary Finishing Files In A Simulated Root Canal Model, Jon Koch, John Borg, Abby Mattson, Kris Olsen, James Bahcall

Mechanical Engineering Faculty Research and Publications

Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was …


High Temperature Thermodynamic Properties Of Znte(S), Robert F. Brebrick Dec 2011

High Temperature Thermodynamic Properties Of Znte(S), Robert F. Brebrick

Mechanical Engineering Faculty Research and Publications

We have gathered the partial pressure, Knudsen cell, and emf measurements on ZnTe(s) from which the Gibbs energy of formation can be calculated. Published partial pressures of diatomic tellurium have been adjusted to take account of a subsequently published third law analysis of tellurium. The equation used to calculate the total pressure from the rate of mass loss from an extensive set of Knudsen cell measurements has been corrected to give a 5% increase in total pressure and the Gibbs energy of formation has been recalculated. A high temperature heat capacity for ZnTe(s) has been selected from the published data. …


Gait Verification Using Knee Acceleration Signals, L. W. Hang, C. Y. Hong, C. W. Yen, D. J. Chang, Mark L. Nagurka Nov 2011

Gait Verification Using Knee Acceleration Signals, L. W. Hang, C. Y. Hong, C. W. Yen, D. J. Chang, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

A novel gait recognition method for biometric applications is proposed. The approach has the following distinct features. First, gait patterns are determined via knee acceleration signals, circumventing difficulties associated with conventional vision-based gait recognition methods. Second, an automatic procedure to extract gait features from acceleration signals is developed that employs a multiple-template classification method. Consequently, the proposed approach can adjust the sensitivity and specificity of the gait recognition system with great flexibility. Experimental results from 35 subjects demonstrate the potential of the approach for successful recognition. By setting sensitivity to be 0.95 and 0.90, the resulting specificity ranges from 1 …


Investigation Of Aluminum Equation Of State Generation, Aaron Ward Oct 2011

Investigation Of Aluminum Equation Of State Generation, Aaron Ward

Master's Theses (2009 -)

There are many forms and methods to construct equations of state, EOSs. These methods are usually tailored for the particular problem of interest. Here, the EOSs of interest are those used in modeling shock responses. These EOSs cover a wide range of physical characteristics such as detonation and explosions, armor and anti-armor materials, and space structures protection. Aluminum will be the primary focus of this work. Aluminum was chosen because it has been studied in great length in the shock regime and is a common component in shock experiments and space type vehicles.