Mechanical Engineering Commons^™

Drive Signal Development For The Thermoacoustic Loudspeaker, Troy Bouman

Dissertations, Master's Theses and Master's Reports

Carbon nanotube thermophones can create acoustic waves from 1 Hz to 100 kHz. The thermoacoustic effect that allows for this non-vibrating sound source is naturally inefficient. Prior efforts have not explored their true efficiency (i.e. the ratio of the total acoustic power to the electrical input power). All previous works have used the ratio of sound pressure to input electrical power. A method for true power efficiency measurement is shown using a fully anechoic technique. True efficiency data are presented for five different drive signal processing techniques: standard alternating current (AC), direct current added to AC (DCAC), amplitude modulation of …

Finite Element Modeling Of Active And Passive Behavior Of The Human Tibialis Anterior: A Preliminary Approach, David Joda

Dissertations, Master's Theses and Master's Reports

This research project serves as exploratory work in the field of computational human biomechanics. A connection between muscular force and intramuscular pressure (IMP) has been uncovered that could prove invaluable in medical diagnostics as a method to circumvent the use of electromyography.

Preliminary finite element simulations were conducted to model the human tibialis anterior muscle in passive lengthening and active contraction. These simulations, totaling over 50 unique runs, utilized a novel constitutive model developed within the IMP research group. Volumetric strain, reaction forces, and pressure gradients were compared to data acquired from ongoing in vivo human experiments. A mechanism for …

Design, Fabrication And Analysis Of An Auxiliary Power Unit On A Heavy-Duty Truck To Power The Hvac Systems Of The Truck During Driver Off-Duty Conditions, Rohan Milind Kalurkar

Dissertations, Master's Theses and Master's Reports

Currently, one of the biggest challenges the world is facing is energy insufficiency. One of the contributors to energy consumption in United States are the idling semi-trailer trucks. In May 2001, President Bush issued The National Energy Policy in which he directed The Environmental Protection Agency (EPA) and Department of Transportation (DOT) to reduce the idling of trucks. This was done in order to reduce energy consumption by lowering fuel consumption and emissions coming out of semi-trailer trucks in the United States of America.

This project deals with the efforts of installing an Auxiliary Power Unit (APU) as a device …

Development And Operation Of A Mobile Test Facility For Education, Christopher Davis

Dissertations, Master's Theses and Master's Reports

The automotive industry saw a large shift towards vehicle electrification after the turn of the century. It became necessary to ensure that new and existing engineers were qualified to design and calibrate these new systems. To ensure this training, Michigan Tech received a grant to develop a curriculum based around vehicle electrification. As part of this agenda, the Michigan Tech Mobile Laboratory was developed to provide hands-on training for professional engineers and technicians in hybrid electric vehicles and vehicle electrification. The Mobile Lab has since then increased the scope of the delivered curriculum to include other automotive areas and even …

Anthropomorphic Robotic Ankle-Foot Prosthesis With Active Dorsiflexion- Plantarflexion And Inversion-Eversion, Evandro Ficanha

Dissertations, Master's Theses and Master's Reports

The main goal of the research presented in this paper is the development of a powered ankle-foot prosthesis with anthropomorphic characteristics to facilitate turning, walking on irregular grounds, and reducing secondary injuries on bellow knee amputees. The research includes the study of the gait in unimpaired human subjects that includes the kinetics and kinematics of the ankle during different types of gait, in different gait speeds at different turning maneuvers. The development of a robotic ankle-foot prosthesis with two active degrees of freedom (DOF) controlled using admittance and impedance controllers is presented. Also, a novel testing apparatus for estimation of …

Transient Thermoelectric Supercooling: Isosceles Current Pulses From A Response Surface Perspective And The Performance Effects Of Pulse Cooling A Heat Generating Mass, Alfred Piggott

Dissertations, Master's Theses and Master's Reports

With increased public interest in protecting the environment, scientists and engineers aim to improve energy conversion efficiency. Thermoelectrics offer many advantages as thermal management technology. When compared to vapor compression refrigeration, above approximately 200 to 600 watts, cost in dollars per watt as well as COP are not advantageous for thermoelectrics. The goal of this work was to determine if optimized pulse supercooling operation could improve cooling capacity or efficiency of a thermoelectric device. The basis of this research is a thermal-electrical analogy based modeling study using SPICE. Two models were developed. The first model, a standalone thermocouple with no …

Elementary Assessments And Simulations Based Proposals For New Heat Transfer Correlations And Flow Regime Maps For Annular/Stratified Regime Of Shear Driven Internal Condensing Flows, Siddharth Ravikumar

Dissertations, Master's Theses and Master's Reports

Contemporary cooling applications necessitate the use of mm-scale shear driven flow condenser designs which also need to ensure substantial heat transfer rates for a wide range of flow conditions. Some modern shear driven flow condensers must meet the requirements of small size and large heat flux removal capability for variety of flow conditions. For this, effective estimates of heat transfer rate correlations and correlations for estimating the length of the annular regime are essential. Existing heat transfer correlations are built based on semi-empirical approaches which are primarily supported by large data sets, which are often mixed with insufficient explanation and …