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2004

University of Nebraska - Lincoln

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Articles 1 - 30 of 148

Full-Text Articles in Mechanical Engineering

Dec 2004, Tractor Museum Dec 2004

Dec 2004, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Introductions Treasurer's Report Curator's Report

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Thermodynamic Analysis Of Separation Systems, Yaşar Demirel Dec 2004

Thermodynamic Analysis Of Separation Systems, Yaşar Demirel

Papers in Thermal Mechanics

Separation systems mainly involve interfacial mass and heat transfer as well as mixing. Distillation is a major separation system by means of heat supplied from a higher temperature level at the reboiler and rejected in the condenser at a lower temperature level. Therefore, it resembles a heat engine producing a separation work with a rather low efficiency. Lost work (energy) in separation systems is due to irreversible processes of heat, mass transfer, and mixing, and is directly related to entropy production according to the Gouy-Stodola principle. In many separation systems of absorption, desorption, extraction, and membrane separation, the major irreversibility …

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Edge-Cracked Orthotropic Bimaterial Butt Joint Under Antiplane Singularity, Xiangfa Wu, Yuris A. Dzenis, Emrah Gokdag Nov 2004

Edge-Cracked Orthotropic Bimaterial Butt Joint Under Antiplane Singularity, Xiangfa Wu, Yuris A. Dzenis, Emrah Gokdag

Department of Engineering Mechanics: Faculty Publications

Explicit elastic solutions are given for an edge-cracked orthotropic bimaterial butt joint under antiplane singularity of a screw dislocation and a line-force. During the procedure, conformal mapping and known dislocation solution are utilized for constructing the fundamental solution to the present problem. Stress intensity factor (SIF) and energy release rate (ERR) of the edge-cracked butt joint are given in closed-form. In limiting cases, results provided in this work cover those in literature.

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Screw Dislocation Interacting With Interfacial Edge-Cracks In Piezoelectric Bimaterial Strips, Xiangfa Wu, Yuris A. Dzenis, Bradley D. Rinschen Nov 2004

Screw Dislocation Interacting With Interfacial Edge-Cracks In Piezoelectric Bimaterial Strips, Xiangfa Wu, Yuris A. Dzenis, Bradley D. Rinschen

Department of Engineering Mechanics: Faculty Publications

This paper is concerned with the interaction between an interfacial edge-crack and a screw dislocation under out-of-plane mechanical and in-plane electric loading in a piezoelectric bimaterial strip. In addition to a discontinuous electric potential across the slip plane, the dislocation is subjected to a line-force and a line-charge at the core. Under the framework of linear piezoelectricity, the out-of-plane displacement and in-plane electric potentials are constructed in closed-form by means of conformal mapping technique and the known solution for screw dislocation in cracked piezoelectric bimaterial. The intensity factors (IFs) and energy release rate (ERR) are derived explicitly.

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Exergy Use In Bioenergetics, Yaşar Demirel Nov 2004

Exergy Use In Bioenergetics, Yaşar Demirel

Papers in Analytical Chemistry

Every developed and adapted biological system extracts useful energy from outside, converts, stores it, and uses for muscular contraction, substrate transport, protein synthesis, and other energy utilizing processes. This energy management in a living cell is called the bioenergetics, and the useful energy is the exergy, which is destroyed in every irreversible process because of the entropy production. The converted exergy is the adenosine triphosphate (ATP) produced through the oxidative phosphorylation coupled to respiration in which the exergy originates from oxidation of reducing equivalents of nutrients. A living cell uses the ATP for all the energy demanding activities; it has …

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Oct 2004, Tractor Museum Oct 2004

Oct 2004, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Old Trusty Show New Paint Scheme History of Ag Engineering Department

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Science For Stewardship: Multidisciplinary Research On Uss Arizona, Matthew A. Russell, Larry E. Murphy, Donald L. Johnson, Timothy J. Foecke, Pamela J. Morris, Raphy Mitchell Oct 2004

Science For Stewardship: Multidisciplinary Research On Uss Arizona, Matthew A. Russell, Larry E. Murphy, Donald L. Johnson, Timothy J. Foecke, Pamela J. Morris, Raphy Mitchell

Department of Mechanical and Materials Engineering: Faculty Publications

The National Park Service’s Submerged Resources Center and USS Arizona Memorial are conducting and coordinating research directed at understanding the nature and rate of natural processes affecting the deterioration of the USS Arizona in Pearl Harbor, Hawaii. The USS Arizona Preservation Project is designed to be multi-year, interdisciplinary and cumulative, with each element contributing to developing an overall management strategy designed to minimize environmental hazard from fuel oil release and provide the basic research required to make informed management decisions for long-term preservation. The primary project focus is toward acquiring requisite data for understanding the complex corrosion and deterioration processes …

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The Effect Of Heterogeneity On Plane Wave Propagation Through Layered Composites, X. Chen, Namas Chandra Aug 2004

The Effect Of Heterogeneity On Plane Wave Propagation Through Layered Composites, X. Chen, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

When laminated composites are subjected to impact loading, the material response is critically determined by the interactions of multiple waves generated at the laminate interfaces. Due to the high complexity arising from the architectural details of composites, layered heterogeneous materials have been studied as the model system to understand the impact behavior of engineering composites. Previously, the present authors have developed an analytical solution to the problem of plate impact of layered systems; plate impact test is a standard boundary value problem used to study high velocity impact behavior both in the elastic and shock wave regimes. In this paper, …

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Spinning Continuous Fibers For Nanotechnology, Yuris A. Dzenis Jun 2004

Spinning Continuous Fibers For Nanotechnology, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

Nanotubes of carbon and other materials are arguably the most fascinating materials playing an important role in nanotechnology today. Their unique mechanical, electronic, and other properties are expected to result in revolutionary new materials and devices. However, these nanomaterials, produced mostly by synthetic bottom-up methods, are discontinuous objects, and this leads to difficulties with their alignment, assembly, and processing into applications. Partly because of this, and despite considerable effort, a viable carbon nanotube–reinforced supernanocomposite is yet to be demonstrated. Advanced continuous fibers produced a revolution in the field of structural materials and composites in the last few decades as a …

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Re-Examination Of “Missing Strain” During Superplastic Deformation Of Aa7475, M. J. Tan, C. L. Chen, Namas Chandra Jun 2004

Re-Examination Of “Missing Strain” During Superplastic Deformation Of Aa7475, M. J. Tan, C. L. Chen, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

“Missing strain,” a discrepancy between the total macroscopic strain and the strain contributed by grain boundary sliding (GBS) during superplastic deformation, appears to exist in previous investigations. In this work, the contri¬bution of GBS (ξGBS) and intragranular strain (ξIG) were simultaneously measured using scratch test conducted on AA7475 samples after deformation at 500 °C at initial strain rate of 10-3 s-1. The result shows that the missing strain results most probably from the neglect of the intragranular strain as well as the anisotropic GBS-induced underesti¬mation of ξGBS. The calculation of ξ …

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Jun 2004, Tractor Museum Jun 2004

Jun 2004, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Vinod Gupta Gift Camp Creek Swap Meet UNL Signage to Museum

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Nebraska Summary S466: Massey Ferguson 6480 Diesel 32-Speed, Nebraska Tractor Test Lab May 2004

Nebraska Summary S466: Massey Ferguson 6480 Diesel 32-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Mar 2004, Tractor Museum Mar 2004

Mar 2004, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Curator's Report Director's Report Treasurer's Report

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Jan 2004, Tractor Museum Jan 2004

Jan 2004, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

NE Museum Budget Cuts Selling Farmall H Husker Harvest Days

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Bar Clamp Having Ergonomic Handle, M. Susan Hallbeck, Myung-Chul Jung Jan 2004

Bar Clamp Having Ergonomic Handle, M. Susan Hallbeck, Myung-Chul Jung

Department of Mechanical and Materials Engineering: Faculty Publications

The present invention generally relates to a handle assembly for a hand operable bar clamp having a fixed jaw, a movable jaw and a drive for translating the movable jaw towards the fixed jaw. The assembly includes a handgrip and a trigger handle. The handgrip having an elongated rear portion has a generally rounded surface and being contoured to complement the natural transverse curve pf a human palm. The trigger handle is pivotal with respect to the handgrip. The trigger handle included an elongated front portion having a rounded front surface and being contoured to complement the natural palmer curve …

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Engineering Mechanics Department Newsletter -- Winter 2004 Jan 2004

Engineering Mechanics Department Newsletter -- Winter 2004

Engineering Mechanics Department: Information

Engineering Mechanics Hosts National Conference
Dzenis Awarded McBroom Professorship
EM Faculty News
EM Faculty Earn College Awards
EM Blackshirts
EM Mourns the Loss of Two Emeriti: Ralph Ekstrom 1923-2003 and Walter Erbach 1919-2003

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Continuum Modeling Of Cell Membranes, Eveline Baesu, R. E. Rudd, J. Belak, M. Mcelfresh Jan 2004

Continuum Modeling Of Cell Membranes, Eveline Baesu, R. E. Rudd, J. Belak, M. Mcelfresh

Department of Engineering Mechanics: Faculty Publications

In this paper, we develop a finite-deformation model for cell membranes with a view toward characterizing the local mechanical response of membranes in atomic force microscope (AFM) experiments. The membrane is modeled as a 2-D fluid continuum endowed with bending resistance. The general theory is used to obtain equations that describe axisymmetric equilibrium states. The membrane is assumed to enclose a fluid medium, which transmits hydrostatic pressure to the membrane, and a point load is applied at the pole to simulate an AFM probe. Both types of loading are associated with a potential and the problem is then cast in …

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Planetary Cliff Descent Using Cooperative Robots, Erik Mumm, Shane Farritor, Paola Pirjanian, Chris Leger, Paul Schenker Jan 2004

Planetary Cliff Descent Using Cooperative Robots, Erik Mumm, Shane Farritor, Paola Pirjanian, Chris Leger, Paul Schenker

Department of Mechanical and Materials Engineering: Faculty Publications

Future robotic planetary exploration will need to traverse geographically diverse and challenging terrain. Cliffs, ravines, and fissures are of great scientific interest because they may contain important data regarding past water flow and past life.
Highly sloped terrain is difficult and often impossible to safely navigate using a single robot. This paper describes a control system for a team of three robots that access cliff walls at inclines up to 70°. Two robot assistants, or anchors, lower a third robot, called the rappeller, down the cliff using tethers. The anchors use actively controlled winches to first assist the rappeller in …

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A Helical Tow Model And Numerical Simulation Of On-Line Thermal Curing Of Thermoset Composites In Filament Winding, Xuefeng Wang, David Y.S. Lou, Negli Zhang` Jan 2004

A Helical Tow Model And Numerical Simulation Of On-Line Thermal Curing Of Thermoset Composites In Filament Winding, Xuefeng Wang, David Y.S. Lou, Negli Zhang`

Department of Mechanical and Materials Engineering: Faculty Publications

A helical tow model of on-line curing of thermoset composites in winding is developed and solved numerically. Actual shape of tow in winding process is considered, and consequently, the modeling of the on-line curing process is more realistic. A numerical grid generation method is developed for the complicated geometry. Transformations of three-dimensional energy equation and its boundary conditions from physical domain to computational domain are performed, which are crucial in numerical grid generation method when an anisotropic medium is involved. A set of concise and regular equations is obtained. The numerical simulation results show that the helical tow model, in …

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Computer Programs For Temperature In Fins And Slab Bodies With The Method Of Green’S Functions, Kevin D. Cole Jan 2004

Computer Programs For Temperature In Fins And Slab Bodies With The Method Of Green’S Functions, Kevin D. Cole

Department of Mechanical and Materials Engineering: Faculty Publications

Heat conduction in fins and slab bodies, a traditional undergraduate topic, is treated with the Green’s function (GF) method. A variety of boundary conditions and heating conditions are included. Computer programs are described which are designed to improve student learning of the GF method. The programs are available from the author.

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Nebraska Summary: S544 Case-Ih Mxu115 Ltd, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary: S544 Case-Ih Mxu115 Ltd, 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 …

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Test 1840: Agco Lt75 Diesel, Nebraska Tractor Test Lab Jan 2004

Test 1840: Agco Lt75 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Test 1841: Agco Lt90 Diesel, Nebraska Tractor Test Lab Jan 2004

Test 1841: Agco Lt90 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Nebraska Summary: S525 New Holland Tl 90a, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary: S525 New Holland Tl 90a, 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 …

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Nebraska Summary 446: Agco Rt135 Powermaxx Diesel, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary 446: Agco Rt135 Powermaxx Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Nebraska Summary 476: Agco Rt 100 Powrmaxx Diesel, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary 476: Agco Rt 100 Powrmaxx Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Nebraska Summary 520: Agco Rt140a Quadrashift Diesel, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary 520: Agco Rt140a Quadrashift Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Nebraska Summary S450: Case Ih Jx 1060c, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary S450: Case Ih Jx 1060c, 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 …

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Nebraska Summary 447: Agco Rt150 Powermaxx Diesel, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary 447: Agco Rt150 Powermaxx Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Nebraska Summary 522: Agco Rt155a Quadrashift Diesel, Nebraska Tractor Test Lab Jan 2004

Nebraska Summary 522: Agco Rt155a Quadrashift Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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