Analysis and calculation of macrosegregation in a casting ingot. MPS solidification model. Volume 1: Formulation and analysis

The physical and numerical formulation of a model for the horizontal solidification of a binary alloy is described. It can be applied in an ingot. The major purpose of the model is to calculate macrosegregation in a casting ingot which results from flow of interdendritic liquid during solidification. The flow, driven by solidification contractions and by gravity acting on density gradients in the interdendritic liquid, was modeled as flow through a porous medium. The symbols used are defined. The physical formulation of the problem leading to a set of equations which can be used to obtain: (1) the pressure field; (2) the velocity field: (3) mass flow and (4) solute flow in the solid plus liquid zone during solidification is presented. With these established, the model calculates macrosegregation after solidification is complete. The numerical techniques used to obtain solution on a computational grid are presented. Results, evaluation of the results, and recommendations for future development of the model are given. The macrosegregation and flow field predictions for tin-lead, aluminum-copper, and tin-bismuth alloys are included as well as comparisons of some of the predictions with published predictions or with empirical data

MPS solidification model. Analysis and calculation of macrosegregation in a casting ingot

Work performed on several existing solidification models for which computer codes and documentation were developed is presented. The models describe the solidification of alloys in which there is a time varying zone of coexisting solid and liquid phases; i.e., the S/L zone. The primary purpose of the models is to calculate macrosegregation in a casting or ingot which results from flow of interdendritic liquid in this S/L zone during solidification. The flow, driven by solidification contractions and by gravity acting on density gradients in the interdendritic liquid, is modeled as flow through a porous medium. In Model 1, the steady state model, the heat flow characteristics are those of steady state solidification; i.e., the S/L zone is of constant width and it moves at a constant velocity relative to the mold. In Model 2, the unsteady state model, the width and rate of movement of the S/L zone are allowed to vary with time as it moves through the ingot. Each of these models exists in two versions. Models 1 and 2 are applicable to binary alloys; models 1M and 2M are applicable to multicomponent alloys

Camp Reading: Logistics of a Revolutionary War Winter Encampment

No abstract is available at this time

Acute Otitis Media

Acute otitis media (AOM) is a common childhood illness that almost every child experiences by the time that they are five years of age. AOM is a self-limiting condition in which analgesics are thought to be efficient in treating the pain in these children. Literature was reviewed and the information that was compiled was presented as a PowerPoint presentationto a local group of mothers with children under the age of 6 years. This information explained the anatomy of the ear, the risk factors for AOM, treatment options, and preventative measures for AOM. As a future Nurse Practitioner, it is imperative that we understand what the needs of the parents are for the children that we are evaluating. It is our duty to provide the education needed and to share in the informed decision making process with the parents when a child is faced with an illness. We need to empower parents and providers to take a stand in a time where overprescribing is a global issue and leading us down a pathway of drug resistance. This is a multifactoral condition where guidelines are in place, but now must be revisited to ensure parents are aware of the treatment plans used to effectively manage AOM

Alien Registration- Poirier, Marie Helene A. (Greenville, Piscataquis County)

https://digitalmaine.com/alien_docs/8433/thumbnail.jp

Explaining the magnetic moment reduction of Fullerene encapsulated Gadolinium through a theoretical model

We propose a Theoretical model accounting for the recently observed reduced magnetic moment of Gadolinium in fullerenes. While this reduction has been observed also for other trivalent rare-hearth atoms (Dy3+, Er3+, Ho3+) in fullerenes and can be ascribed to crystal field effects, the explanation of this phenomena for Gd3+ is not straightforward due to the sphericity of its ground state (S=7/2, L=0). In our model the momentum lowering is the result of a subtle interplay between hybridisation and spin-orbit interaction