# Mechanical Engineering Commons™

Articles 1 - 6 of 6

## Full-Text Articles in Mechanical Engineering

Die Soldering: Mechanism Of The Interface Reaction Between Molten Aluminum Alloy And Tool Steel, Sumanth Shankar, Diran Apelian Jun 2002

#### Die Soldering: Mechanism Of The Interface Reaction Between Molten Aluminum Alloy And Tool Steel, Sumanth Shankar, Diran Apelian

##### Mechanical Engineering Faculty Publications

Die soldering is the result when molten aluminum sticks to the surface of the die material and remains there after the ejection of the part; it results in considerable economic and production losses in the casting industry, and is a major quality detractor. In order to alleviate or mitigate die soldering, one must have a thorough understanding of the mechanism by which the aluminum sticks to the die material. A key question is whether the die soldering reaction is diffusion controlled or interface controlled. A set of diffusion couple experiments between molten aluminum alloy and the ferrous die was carried ...

Mathematical Modeling And Computer Simulation Of The Rotating Impeller Particle Flotation Process: Part I. Fluid Flow, Mohammed D. Maniruzzaman, Makhlouf M. Makhlouf Apr 2002

#### Mathematical Modeling And Computer Simulation Of The Rotating Impeller Particle Flotation Process: Part I. Fluid Flow, Mohammed D. Maniruzzaman, Makhlouf M. Makhlouf

##### Mechanical Engineering Faculty Publications

Removal of unwanted particles from molten metal by flotation is one of the most useful melt cleansing techniques used by the foundry industry. An effective way of flotation of particles in a melt relies on purging a gas into the molten metal through holes in a rotating impeller. Impeller rotation creates turbulence inside the melt, which helps agglomerate the impurity particles and. thereby, enhances their removal from the melt. In addition, turbulence increases the probability of particles attaching to the rising gas bubbles and, therefore, enhances the chance of their removal from the molten metal. A mathematical model has been ...

Mathematical Modeling And Computer Simulation Of The Rotating Impeller Particle Flotation Process: Part Ii. Particle Agglomeration And Flotation, Mohammed D. Maniruzzaman, Makhlouf M. Makhlouf Apr 2002

#### Mathematical Modeling And Computer Simulation Of The Rotating Impeller Particle Flotation Process: Part Ii. Particle Agglomeration And Flotation, Mohammed D. Maniruzzaman, Makhlouf M. Makhlouf

##### Mechanical Engineering Faculty Publications

Effective removal of unwanted particles from a molten metal alloy by flotation relies on purging a gas into the melt through a rotating impeller. This device is commonly known as a rotary degasser. Unwanted particles in the melt attach to the rising gas bubbles and rise to the slag layer where they are removed from the metal bulk. In addition, the turbulence created by the rotating impeller causes the randomly distributed solid particles to agglomerate into relatively large clusters. These clusters float up or settle down due to the difference between their density and that of the melt. A mathematical ...

Investigation Of Fatigue Crack Initiation In Ti-6al-4v During Tensile-Tensile Fatigue, Svetlana G. Ivanova, Ronald R. Biederman, Richard D. Sisson Jr. Apr 2002

#### Investigation Of Fatigue Crack Initiation In Ti-6al-4v During Tensile-Tensile Fatigue, Svetlana G. Ivanova, Ronald R. Biederman, Richard D. Sisson Jr.

##### Mechanical Engineering Faculty Publications

Fatigue crack initiation in Ti-6Al-4V has been investigated in high cycle fatigue (HCF) and low cycle fatigue (LCF) regimes at stress ratio R = 0.1 using the replication technique. In all four tested α/β microstructures, the crack was initiated by fracture of equiaxed alpha grain. Fractured alpha grains are seen on the fracture surface as flat facets with features characteristic of cleavage fracture. In the regime of low stress amplitudes and in the absence of reverse loading, cleavage fracture contributes to crack initiation and early stages of crack growth in Ti-6Al-4V. This mechanism is discussed in relation to the ...

Lotka-Volterra System In A Random Environment, Mikhail F. Dimentberg Mar 2002

#### Lotka-Volterra System In A Random Environment, Mikhail F. Dimentberg

##### Mechanical Engineering Faculty Publications

Classical Lotka-Volterra (LV) model for oscillatory behavior of population sizes of two interacting species (predator-prey or parasite-host pairs) is conservative. This may imply unrealistically high sensitivity of the system's behavior to environmental variations. Thus, a generalized LV model is considered with the equation for preys' reproduction containing the following additional terms: quadratic "damping'' term that accounts for interspecies competition, and term with white-noise random variations of the preys' reproduction factor that simulates the environmental variations. An exact solution is obtained for the corresponding Fokker-Planck-Kolmogorov equation for stationary probability densities (PDF's) of the population sizes. It shows that both ...

Jan 2002

#### A Model-Based Fault Detection And Diagnosis Scheme For Distributed Parameter Systems: A Learning Systems Approach, Michael A. Demetriou

##### Mechanical Engineering Faculty Publications

In this note, fault detection techniques based on finite dimensional results are extended and applied to a class of infinite dimensional dynamical systems. This special class of systems assumes linear plant dynamics having an abrupt additive perturbation as the fault. This fault is assumed to be linear in the (unknown) constant (and possibly functional) parameters. An observer-based model estimate is proposed which serves to monitor the system's dynamics for unanticipated failures, and its well posedness is summarized. Using a Lyapunov synthesis approach extended and applied to infinite dimensional systems, a stable adaptive fault diagnosis (fault parameter learning) scheme is ...