Mechanical Engineering Commons^™

Single-Sided Crash Cushion System, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A single-sided crash attenuation cushion system having an impact head and three stage energy absorption mechanism. The energy absorbing mechanism has a mandrel for deforming thin-walled tubes in a controlled collapse to absorb impact forces from a colliding vehicle. The third stage of the absorption mechanism includes an additional deformable compressible tube between the fixed-object hazard and the thin walled tubes.

Tribo-Surface Characteristics Of Al-B4c And Al-Sic Composites Worn Under Different Contact Pressures, Haseeb Asma

Haseeb ASMA

Tribo-surface characteristics of two aluminium metal matrix composites (Al-MMC) of compositions Al-13 vol%B4C and Al-13 vol%SiC sliding against a commercial phenolic brake pad have been investigated under dry conditions. The wear tests were carried out using a pin-on-disc type apparatus at a linear speed of 1.62 ms(-1) under contact pressures ranging from 0.75 to 3.00 MPa. The coefficient of friction was recorded on line. Wear rates were calculated from mass loss measurements. Scanning electron microscope equipped with energy dispersive X-ray spectroscopy was used to examine the tribo-surface. It is found that wear rate of both composites increases with increasing contact …

Modeling Of The Effects Of Athermal Flow Strength And Activation Energy For Dislocation Glide An The Nanoindentation Creep Of Nickel Thin Film At Room Temperature, Haseeb Asma

Haseeb ASMA

Nanoindentation creep behaviour of nickel at room temperature has been modeled based on the obstacle-controlled dislocation glide mechanism. Using the model, the effects of two important materials parameters viz. the activation free energy required by dislocation to overcome an obstacle without any aid from external stress, Delta F and the athermal flow strength, tau(0), which is the flow strength of solids at 0 K are systematically studied. It has been found that Delta F plays a dominant role in room temperature creep properties of nickel. The role of Delta F is particularly dominant in determining the time dependent deformation. On …

End Splice Assembly For Box-Beam Guardrail And Terminal Systemis, John D. Reid, John R. Rohde, Dean L. Sicking, King K. Mak

Department of Mechanical and Materials Engineering: Faculty Publications

An end splice assembly for a box-beam guardrail and terminal system having a first stage rail element and a second stage rail element. The assembly has two major connecting components. Upper and lower bent plate channels and upper and lower channel splice plates. The channels and plates have side walls which extend laterally to one another when the two rail elements are mated. The channels and plates are fastened together to provide moment strength to the splice within the system.

Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings, Hai Ni, Xiaodong Li

Faculty Publications

Nano-/micronecklaces with SiO₂ beads in boron strings were synthesized by simply sublimating the desired powders in a sealed quartz tube at high temperature. The boron strings have a rectangular cross section with width varying from 80to1000nm while the SiO₂ beads bear either spindle or spherical shape with a size ranging from 100nmto5μm. The spacing between the SiO₂ beads is uniform in each boron string. Both the boron strings and the SiO₂ beads are amorphous and free of defects. The supersaturated vapors of silicon and oxygen induced the SiO₂ bead formation.

Preparation Of High-Strength Nanometer Scale Twinned Coating And Foil, Xinghang Zhang, Amit Misra, Michael Nastasi, Richard G. Hoagland

Department of Mechanical and Materials Engineering: Faculty Publications

Very high strength single phase stainless steel coating has been prepared by magnetron sputtering onto a substrate. The coating has a unique microstructure of nanometer spaced twins that are parallel to each other and to the substrate surface. For cases where the coating and substrate do not bind strongly, the coating can be peeled off to provide foil.

Modeling And Representation Of Geometric Tolerances Information In Integrated Measurement Processes, Xiaoping Zhao, T. M. Kethara Pasupathy, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

Modeling and representation of geometric tolerances information across an enterprise is viable due to the advances in Internet technologies and increasing integration requirements from industry. In Integrated Measurement Processes (IMP), geometric tolerances data model must support different models from several well-defined standards: including ASME Y14.5M-1994, STEP, DMIS, and others. In this paper, we propose a layered conformance level geometric tolerances representation model. This model uses the widely applied ASME Y14.5M-1994 as its foundation layer by abstracting most information from this standard. The additional geometric tolerances information defined by DMIS and STEP is incorporated into this model to form corresponding conformance …

Flexible Tools For Specifying Design Variation, Trichy Pasupathy, Xiaoping Zhao, Robert Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

This paper describes flexible tools for specifying design variations that are based on nonuniform profile tolerance definitions. These tools specify bounds of design performance that can be used for negotiation among engineers in a collaborative design process. These specification methods allow for the capture of many different design functions that are not easily described with current tool designs. In addition, these specification methods lend themselves to efficient verification methods. Profile tolerance definitions provide the most general variation controls for complex mechanical surfaces. Common design practices and engineering standards for profile tolerances exhibit many weaknesses and limitations. We present a rationale …

Nanoparticle-Induced Negative Differential Resistance And Memory Effect In Polymer Bistable Light-Emitting Device, Ricky J. Tseng, Jianyong Ouyang, Chih-Wei Chu, Jinsong Huang, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Recently, electrical bistability was demonstrated in polymer thin films incorporated with metal nanoparticles [J. Ouyang, C. W. Chu, C. R. Szmanda, L. P. Ma, and Y. Yang, Nat. Mater. 3, 918 (2004)]. In this letter, we show the evidence that electrons are the dominant charge carriers in these bistable devices. Direct integration of bistable polymer layer with a light-emitting polymer layer shows a unique light-emitting property modulated by the electrical bistability. A unique negative differential resistance induced by the charged gold nanoparticles is observed due to the charge trapping effect from the nanoparticles when interfaced with the light-emitting layer.

The Role Of Electrospinning In The Emerging Field Of Nanomedicine, S. Y. Chew, Y. Wen, Yuris A. Dzenis, K. W. Leong

Department of Mechanical and Materials Engineering: Faculty Publications

The fact that in vivo the extracellular matrix or substratum with which cells interact often includes topography at the nanoscale underscores the importance of investigating cell-substrate interactions and performing cell culture at the submicron scale. An important and exciting direction of research in nanomedicine would be to gain an understanding and exploit the cellular response to nanostructures. Electrospinning is a simple and versatile technique that can produce a macroporous scaffold comprising randomly oriented or aligned nanofibers. It can also accommodate the incorporation of drug delivery function into the fibrous scaffold. Endowed with both topographical and biochemical signals such electrospun nanofibrous …

Piezoelectromagnetic Waves In A Ceramic Plate Between Two Ceramic Half-Spaces, S. N. Jiang, Q. Jiang, X. F. Li, S. H. Guo, H. G. Zhou, J. S. Chang

Department of Mechanical and Materials Engineering: Faculty Publications

We analyze the propagation of piezoelectromagnetic waves guided by a plate of polarized ceramics between two ceramic half-spaces. An exact dispersion relation is obtained, which reduces to a few known elastic, electromagnetic, and quasistatic piezoelectric wave solutions in the literature as special cases. Numerical solutions to the equation that determines the dispersion relation show the existence of guided waves. The results are useful for acoustic wave and microwave devices.

Non-Operative Management Of Posterior Tibialis Tendon Dysfunction: Design Of A Randomized Clinical Trial [Nct00279630], Kornelia Kulig, Amy B. Pomrantz, Judith M. Burnfield, Stephen F. Reischl, Susan Mais-Requejo, David B. Thordarson, Ronald W. Smith

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Posterior tibialis tendon dysfunction (PTTD) is a common cause of foot pain and dysfunction in adults. Clinical observations strongly suggest that the condition is progressive. There are currently no controlled studies evaluating the effectiveness of exercise, orthoses, or orthoses and exercise on Stage I or IIA PTTD. Our study will explore the effectiveness of an eccentric versus concentric strengthening intervention to results obtained with the use of orthoses alone. Findings from this study will guide the development of more efficacious PTTD intervention programs and contribute to enhanced function and quality of life in persons with posterior tibialis tendon dysfunction. …

Efficient Inverted Polymer Solar Cells, G. Li, C.-W. Chu, V. Shrotriya, Jinsong Huang, Y. Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We investigate the effect of interfacial buffer layers—vanadium oxide (V₂O₅) and cesium carbonate (Cs₂CO₃)—on the performance of polymer solar cells based on regioregular poly-(3-hexylthiophene) and [6,6]-phenyl C₆₀ butyric acid methyl ester blend. The polarity of solar cells can be controlled by the relative positions of these two interfacial layers. Efficient inverted polymer solar cells were fabricated with the structure of indium tin oxide (ITO)/Cs₂CO₃/polymer blend/vanadium oxide (V₂O₅)/aluminum (Al). Short-circuit current of 8.42 mA/cm2, open-circuit voltage of 0.56 V, and power conversion efficiency of …

Improving The Power Efficiency Of White Light-Emitting Diode By Doping Electron Transport Material, Jinsong Huang, Wei-Jen Hou, Juo-Hao Li, Gang Li, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Highly efficient white light emission was realized via the partial energy transfer from blue host polyfluorene (PF) to orange light emission dopant rubrene. A more balanced charge transport was achieved by adding an electron transport material, 2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD), into the PF-rubrene system to enhance the electron transportation. Efficiency improvement by as much as a factor of 2 has been observed through the addition of PBD. These devices can easily reach high luminance at low driving voltages, thus achieving high power efficiency at high luminance (14.8, 13.5, and 12.0 lm/W at the luminances of 1000, 2000, and 4000 cd/m², …

In Vivo Laparoscopic Robotics, Mark E. Rentschler, Stephen R. Platt, Jason Dumpert, Shane M. Farritor, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

Robotic laparoscopic surgery is evolving to include in vivo robotic assistants. The impetus for the development of this technology is to provide surgeons with additional viewpoints and unconstrained manipulators that improve safety and reduce patient trauma. A family of these robots have been developed to provide vision and task assistance. Fixed-base and mobile robots have been designed and tested in animal models with much success. A cholecystectomy, prostatectomy, and nephrectomy have all been performed with the assistance of these robots. These early successful tests show how in vivo laparoscopic robotics may be part of the next advancement in surgical technology.

Test 1881: Mccormick Xtx 200/Mtx 185 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1890: John Deere 8530 Ivt, Nebraska Tractor Test Lab, John Deere

Nebraska Tractor Tests

No abstract provided.

Test 1889: John Deere 8430t 16 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1873: John Deere 8430 16 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1874: John Deere 8430 Ivt, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1883: Agco Lt75a Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1882: Mccormick Xtx 215 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1880: Mccormick Xtx 185/Mccormick Mtx 165 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1875: Challenger Mt 635b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1876: Challenger Mt 645b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1877: Challenger Mt 655b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1878: Challenger Mt 665b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1891: Kubota L5030 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1885: John Deere 8230 Diesel 16-Speed, 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 1886: John Deere 8230t Diesel 16-Speed, 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 …