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Carbon Diffusion In Steels: A Numerical Analysis Based On Direct Integration Of The Flux, Olga Karabelchtchlkova, Richard D. Sisson Jr. Dec 2006

Carbon Diffusion In Steels: A Numerical Analysis Based On Direct Integration Of The Flux, Olga Karabelchtchlkova, Richard D. Sisson Jr.

Mechanical Engineering Faculty Publications

In the early 1970s, Professor Dayananda developed a technique for the direct integration of fluxes from the concentration profiles in vapor-solid diffusion couples to determine diffusion coefficients and atomic mobilities. As part of a project to control and optimize the industrial carburization process in mild- and low-alloyed steels, a modified integration analysis was applied to determine the mass transfer coefficient in the gas boundary layer and carbon diffusivity in austenite. Because carbon flux and surface carbon content vary with time during single-stage carburizing even with a fixed carbon potential in the atmosphere, a mass balance at the gas-solid interface must ...


Guest Editorial, Yongho Sohn, Carelyn Campbell, John E. Morral, Richard D. Sisson Dec 2006

Guest Editorial, Yongho Sohn, Carelyn Campbell, John E. Morral, Richard D. Sisson

Mechanical Engineering Faculty Publications

No abstract provided.


Fatigue Crack Growth Mechanisms At The Microstructure Scale In Al-Si-Mg Cast Alloys: Mechanisms In Regions Ii And Iii, Diana A. Lados, Diran Apelian, J. Fred Major Aug 2006

Fatigue Crack Growth Mechanisms At The Microstructure Scale In Al-Si-Mg Cast Alloys: Mechanisms In Regions Ii And Iii, Diana A. Lados, Diran Apelian, J. Fred Major

Mechanical Engineering Faculty Publications

The fatigue crack growth behavior in Regions 11 and III of crack growth was investigated for hypoeutectic and eutectic Al-Si-Mg cast alloys. To isolate and establish the mechanistic contributions of characteristic microstructural features (dendritic α-Al matrix, eutectic phases, Mg-Si strengthening precipitates), alloys with various Si content/morphology, grain size level, and matrix strength were studied; the effect of secondary dendrite arm spacing (SDAS) was also assessed. In Regions 11 and III of crack growth, the observed changes in the fracture surface appearance were associated with changes in crack growth mechanisms at the microstructural scale (from a linear advance predominantly through ...


Fluidized Bed Heat Treatment Of Cast Al-Si-Cu-Mg Alloys, S. K. Chaudhury, Diran Apelian Jul 2006

Fluidized Bed Heat Treatment Of Cast Al-Si-Cu-Mg Alloys, S. K. Chaudhury, Diran Apelian

Mechanical Engineering Faculty Publications

The effects of fluidized bed heat treatment on the microstructural and mechanical properties of Al-SiCu-Mg cast alloys, namely, 354 and 319, were studied. The heating rate in fluidized beds (FBs) is greater vis-a-vis conventional electrical resistance furnaces (CFs). The high heating rate in FBs increases the kinetics of metallurgical phenomena such as Si fragmentation and spherodization during solution heat treatment, as well as the precipitation rate of phases such as Al5Cu2Mg8Si6 and Al2Cu during aging. It is observed that the dissolution rate of phases such as Mg2Si and A15Cu2Mg8Si6 takes place very rapidly. The solution heat treatment of 319 alloy ...


Design And Development Of A Transhumeral Prosthetic Mounting System, Michael Bertini, Zachary Dominguez, Joshua Morin, Elizabeth Palumbo Apr 2006

Design And Development Of A Transhumeral Prosthetic Mounting System, Michael Bertini, Zachary Dominguez, Joshua Morin, Elizabeth Palumbo

Assistive Technology Resource Center Projects

For those with amputations, prostheses are important tools which are needed to perform many activities of daily living. Ideally, a prosthesis enables the user to perform activities with the same freedom as a physically able person. For those with trans-humeral amputations, however, effective prosthesis use is often hindered by the complexity of the glenohumeral joint. Current methods of prosthesis attachment for those with trans-humeral amputations severely limit load bearing capability. The goal of this project was to design, analyze, manufacture, and test a device that increases current axial and torsional load bearing capability without limiting the range of motion in ...


The Design And Manufacture Of An Elevating/Articulating Manual Wheelchair Legrest, Eric Couture Apr 2006

The Design And Manufacture Of An Elevating/Articulating Manual Wheelchair Legrest, Eric Couture

Assistive Technology Resource Center Projects

For people bound to a wheelchair, the ability to elevate one's legs is as much a comfort concern as it is a health concern. The elevation of one's legs changes the user's sitting position, thereby increasing their comfort level while at the same time increasing circulation, ultimately aiding in the prevention of pressure sores and lower extremity swelling. Unfortunately, the motion of current legrests on manual wheelchairs does not accurately match the motion of the user's lower leg. This mismatch of motion causes the legrest to push up on the leg, shortening it while applying torque ...


Authors' Reply To Reply Of Discussion On "Nucleation Mechanism Of Eutectic Phases In Aluminum-Silicon Hypoeutectic Alloys", S. Shankar, Makhlouf M. Makhlouf Apr 2006

Authors' Reply To Reply Of Discussion On "Nucleation Mechanism Of Eutectic Phases In Aluminum-Silicon Hypoeutectic Alloys", S. Shankar, Makhlouf M. Makhlouf

Mechanical Engineering Faculty Publications

No abstract provided.


Design Of A Power-Assist Hemiplegic Wheelchair, Keith Liadis Mar 2006

Design Of A Power-Assist Hemiplegic Wheelchair, Keith Liadis

Assistive Technology Resource Center Projects

Current one-handed manual wheelchairs are difficult to propel because one arm can only provide half the power that is ascertained in a two-handed manual wheelchair. A power-assisted hemiplegic (one-sided paralysis) wheelchair was developed that can effectively be propelled with one arm while remaining maneuverable, lightweight, and foldable. An existing manual wheelchair was minimally modified and fitted with powerassisted components that could alternatively be attached to a wide range of manual wheelchairs. The design implements a motor and gear train to power the wheel on the user’s affected side, encoders on both rear wheels to track wheel position, and a ...


Effects Of Rapid Heating On Solutionizing Characteristics Of Al-Si-Mg Alloys Using A Fluidized Bed, S. K. Chaudhury, Diran Apelian Mar 2006

Effects Of Rapid Heating On Solutionizing Characteristics Of Al-Si-Mg Alloys Using A Fluidized Bed, S. K. Chaudhury, Diran Apelian

Mechanical Engineering Faculty Publications

Effects of rapid heat transfer using a fluidized bed on the heat-treating response of Al-Si-Mg alloys (both unmodified and Sr modified) were investigated. The heating rate in the fluidized bed is greater than in conventional air convective furnaces. Particle size analyses of eutectic Si showed that the high heating rate during fluidized bed solution heat treatment causes faster fragmentation and spherodization of Si particles compared to conventional air convective furnaces. The mechanism of Si fragmentation through fluidized bed processing is through both brittle fracture and neck formation and its propagation. In contrast to this, the mechanism of Si fragmentation using ...


The Effect Of Residual Stress On The Fatigue Crack Growth Behavior Of Al-Si-Mg Cast Alloys - Mechanisms And Corrective Mathematical Models, Diana A. Lados, Diran Apelian Jan 2006

The Effect Of Residual Stress On The Fatigue Crack Growth Behavior Of Al-Si-Mg Cast Alloys - Mechanisms And Corrective Mathematical Models, Diana A. Lados, Diran Apelian

Mechanical Engineering Faculty Publications

The fatigue crack growth (FCG) behavior of various types of alloys is significantly affected by the presence of residual stress induced by manufacturing and post-manufacturing processes. There is a qualitative understanding of the effects of residual stress on fatigue behavior, but the effects are not comprehensively quantified or accounted for. The difficulty in quantifying these effects is largely due to the complexity of residual-stress measurements (especially considering that parts produced in similar conditions can have different residual-stress levels) and the lack of mathematical models able to convert experimental data with residual stress into residual-stress-free data. This article provides experimental, testing ...


Reza Abbaschian - 2006 President Of, Asm International, Diran Apelian Jan 2006

Reza Abbaschian - 2006 President Of, Asm International, Diran Apelian

Mechanical Engineering Faculty Publications

No abstract provided.