Mechanical Engineering Commons^™

Effects Of Noise, Reverberation And Foreign Accent On Native And Non-Native Listeners’ Performance Of English Speech Comprehension, Zhao Ellen Peng, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

A large number of non-native English speakers may be found in American classrooms, both as listeners and talkers. Little is known about how this population comprehends speech in realistic adverse acoustical conditions. A study was conducted to investigate the effects of background noise level (BNL), reverberation time (RT), and talker foreign accent on native and non-native listeners' speech comprehension, while controlling for English language abilities. A total of 115 adult listeners completed comprehension tasks under 15 acoustic conditions: three BNLs (RC-30, RC-40, and RC-50) and five RTs (from 0.4 to 1.2 s). Fifty-six listeners were tested with speech from native …

Design And Optimization Of Membrane-Type Acoustic Metamaterials, Matthew G. Blevins

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

One of the most common problems in noise control is the attenuation of low frequency noise. Typical solutions require barriers with high density and/or thickness. Membrane-type acoustic metamaterials are a novel type of engineered material capable of high low-frequency transmission loss despite their small thickness and light weight. These materials are ideally suited to applications with strict size and weight limitations such as aircraft, automobiles, and buildings. The transmission loss profile can be manipulated by changing the micro-level substructure, stacking multiple unit cells, or by creating multi-celled arrays. To date, analysis has focused primarily on experimental studies in plane-wave tubes …

An Evaluation Of Agricultural Tractors Hydraulic Lift Performance, Grant W. Melotz

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The current OECD Code 2 detailing the procedures for the hydraulic lift test of agricultural tractors, section 4.3, published lift values that were sometimes unattainable. The static weight of 2WD, two wheel drive, and MFWD, mechanical front wheel drive, tractors and the amount of lifting force have increased at a greater rate than the amount of static weight on the front axle. This increase in lifting force has led to a decrease in the percent of weight as the upward support force on the front axle of a tractor. Many of the 2WD and MFWD unballasted tractors tested at the …

Tractor Measurement And Data Acquisition System For Hydraulic Power, Draft Force, And Power Take-Off Torque, James Roeber

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Numerous advancements in machinery performance of agricultural tractors have been made in recent years. The Organisation for Economic Co-operation and Development (OECD) tests predetermined points (e.g., maximum power and torque) for drawbar, Power Take-Off (PTO), and hydraulic power as separate tests for tractor performance. Testing methods with the tractor operating at a steady state have been done for years, which were uncharacteristic of agricultural tractor operations in field conditions. As part of this thesis work, field usable data acquisition systems (DAQs) were developed to record implement energy consumption (e.g., drawbar loading, PTO torque, and hydraulic power). The system used LabVIEW …

Mild Traumatic Brain Injury: Combined In Silico And In Vitro Studies, Yi Hua

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Mild traumatic brain injury (TBI) is a significant public health concern worldwide and has attracted significant attention due to high-impact sport as well as improvised explosive devices used in military conflicts. The earliest sign of mild TBI is associated with cognitive, behavioral and physical/somatic changes, which are commonly invisible to existing medical techniques. Thus it is essential to target mechanisms of mild TBI and its associated damage measures for earlier diagnosis/treatment and enhanced protection strategies.

In this work, the mechanism of blast-induced mild TBI was inspected through integrated in silico and in vitro models. A three-dimensional (3D) human head model …

Improving Radiation And Stress Corrosion Cracking Resistance Of Austenitic Stainless Steels By Laser Shock Peening, Qiaofeng Lu

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Structural alloys for Generation-IV nuclear reactors need to endure a high neutron dose, high temperature, and corrosive coolant. Austenitic stainless steels, particularly the oxide-dispersion-strengthened (ODS) austenitic steels, are promising candidate materials, but they suffer several limits such as irradiation damage and stress corrosion cracking (SCC). This research applies a laser shock peening (LSP) process to improve the radiation and SCC resistance of austenitic stainless steels in simulated nuclear reactor environments. A high density dislocation networks, stacking faults and twin boundaries were generated in the surface region of 304 steels by the shock wave-material interactions in the LSP process. In-situ TEM …

Automated Mini-Channel Platform For Studying Plant Root Environments, Kevin F. Kreis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Plants are crucial to our lives; they provide us with building materials, oxygen, and food. A season’s crop yield can be significantly affected by local environmental factors. Farming practices currently focus on using fertilizer, pesticides, monitoring water availability, and genetic modification of the plant to increase crop yield. Improving fundamental understanding of plant root interactions with their local soil environment, or rhizosphere, will help improve crop yield. Studying such interactions is challenging because roots are underground, making it difficult to observe interactions and to manipulate the local soil environment.

The goal of this thesis is to develop an automated mini-channel …

Design Of Medical Devices For Diagnostics In The Gastrointestinal System, Charles R. Welch

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents the design, controls, and testing of two systems: a novel colonoscope locomotion design for diagnostics, and a biosensor capsule that implants a sensor in the small intestine. Each system requires special design considerations for use in the gastrointestinal system.

Colonoscopy procedures are recommended as a screening for colon cancer and related conditions after the age of 50. The need for an improved colonoscope that reduces the colonoscopy time and patient discomfort is apparent. The semi-autonomous device presented here could likely reduce the colonoscopy procedure time by allowing the physician to focus more on the diagnosis and less …

Leidenfrost Energy Barriers, James Peck, Anton Hassebrook, Craig Zuhlke, Troy P. Anderson, Dennis R. Alexander, George Gogos, Sidy Ndao

UCARE: Research Products

In this work, an “Energy Barrier” was created to control the motion of Leidenfrost droplets. This barrier was created by functionalizing a portion of a mirror-polished stainless steel 304 surface with Femtosecond Laser Surface Processing (FLSP). FLSP results in superhydrophilic, hierarchical, micro- and nanostructures which are highly wetting and thus have an increased Leidenfrost temperature. Water droplets in the film boiling state were deposited, and propelled by gravity towards the Energy Barrier interface. Room temperature droplets were deposited over a range of surface temperatures beginning with the Leidenfrost temperature of mirror-polished stainless steel 304 and culminating at the Leidenfrost temperature …

Modeling Of Methane Tank Depressurization In Cold Weather, Brittney Bridger-Burton, Kevin D. Cole

UCARE: Research Products

Non-metallic tanks are used in industry to store and transfer gasses such as methane. As the tanks are emptied, the properties of the gas change, causing heat transfer with the tank wall. When emptied while at low temperatures, liquid condensation can form and the tank lining can reach a critically low temperature, causing fracture to the tank wall. In this study, the emptying of methane in cold weather conditions from a non-metallic tank was modelled using Aspen Tech Software. A full tank of methane, at 250 bar and 288 K, was cooled to the following starting temperatures: 263, 253, 243, …

Molecular Combing Of Dna Nanofibers And Comparison To Electrospinning, Tanner L. Buresh

UCARE: Research Products

The goal of these experiments was to create DNA nanofibers through the method of molecular combing (MC) and then compare the MC fibers to fibers created with electrospinning (ES). The experiment was designed and initial samples were created. After confirming that the method would succeed in creating DNA fibers, several parametric studies were performed in order to optimize the experiment and create the most uniform fibers possible. The parametric studies were done on the following variables: substrate material, pH level of DNA solution, and DNA solution concentration. After completion of all experiments, it was determined that although fibers could be …

Drag Reduction Using Femtosecond Laser Surface Processing: Experimental Setup, Derek Wallin, Henry Ems, Craig Zuhlke, Dennis R. Alexander, George Gogos, Sidy Ndao

UCARE: Research Products

The experimental setup for developing a system to test the drag effects of different superhydrophorbicities. This is used to revise the current Moody Chart and redefine fluid drag in a pipe.

Fluid drag reduction is important in many applications such as reducing the power requirement to pump a fluid through a channel or pipe. The Center for Electro-Optics and Functionalized Surfaces (CEFS) at the University of Nebraska – Lincoln uses a femtosecond laser to functionalize 304 stainless Steel to become superhydrophilic or superhydrophobic The Processing produces microscale and nanoscale surface roughness that when treated with siloxanes becomes superhydrophobic. Small vortices …

Development Of A Robust Setup For The Study Of Wetting Characteristics Of Low Melting Point Metals, John D. Casias, Ethan Allan Davis, Sidy Ndao

UCARE: Research Products

• Energy use is very inefficient

• Approx. 60% rejected mostly in the form of waste heat

• Low melting point metals are promising for applications in thermal energy management, conversion, and storage

Design And Testing Of Robotic Capsule Biosensors In The Small Intestine, Zachary Bram

Robotics and Mechanical Systems Design

Biosensors are a tool that is growing in usage and is sought out by doctors and patients alike for being a non-invasive method to monitor health. The data that can be collected from these sensors can be analyzed by doctors that are away from patients, or even by patients that do not have the ability to see a doctor. The purpose of this work is to design and test a biosensor capsule that can attach itself to the inner wall of the small intestine for a short period of time before exiting the body. This research project was a continuation …

Method For Hyper-Polarizing Nuclear Spns At Arbtrary Magnetic Felds, Carlos A. Meriles, Daniela Pagliero, Abdelghani Laraoui

Department of Mechanical and Materials Engineering: Faculty Publications

A method of dynamically polarizing the nuclear spin host of nitrogen-vacancy (NV) centers in diamond is provided. The method uses optical, microwave and radio-frequency pulses to recursively transfer spin polarization from the NV electronic spin. Nitrogen nuclear spin initialization approaching 80% at room temperature is demonstrated both in ensemble and single NV centers without relying on level anti-crossings. This makes the method applicable at arbitrary magnetic fields.

Nebraska Summary: S1059a Massey Ferguson 7715s, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1073 New Holland T7.175, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1098 New Holland T6.145, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2171: John Deere 9520rx, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1075 New Holland T7.210, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1122 Massey Ferguson 6715s, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1063 Massey Ferguson 7718, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1102 New Holland T6.180, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1095 Case-Ih Maxxum 135, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1083 Case-Ih Puma 200, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2162a: New Holland T9.645, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1060a Massey Ferguson S7715s, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1072 Challenger Mt545e, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1114 John Deere 6195m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Temperature-Dependent Helium Ion-Beam Mixing In An Amorphous Sioc/Crystalline Fe Composite, Qing Su, Lloyd Price, Lin Shao, Michael Nastasi

Department of Mechanical and Materials Engineering: Faculty Publications

Temperature dependent He-irradiation-induced ion-beam mixing between amorphous silicon oxycarbide (SiOC) and crystalline Fe was examined with a transmission electron microscope (TEM) and via Rutherford backscattering spectrometry (RBS). The Fe marker layer (7.2 ± 0.8 nm) was placed in between two amorphous SiOC layers (200 nm). The amount of ion-beam mixing after 298, 473, 673, 873, and 1073 K irradiation was investigated. Both TEM and RBS results showed no ion-beam mixing between Fe and SiOC after 473 and 673 K irradiation and a very trivial amount of ion-beam mixing (~2 nm) after 298 K irradiation. At irradiation temperatures higher than 873 …