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

Computer simulation of macrosegregation in directionally solidified circular ingots

The formulation and employment of a computer code designed to simulate the directional solidification of lead-rich Pb-Sn alloys in the form of an ingot with a uniform and circular cross-section are described. The formulation is for steady-state solidification in which convection in the all-liquid zone is ignored. Particular attention was given to designing a code to simulate the effect of a subtle variation of temperature in the radial direction. This is important because a very small temperature difference between the center and the surface of the ingot (e.g., less than 0.5 C ) is enough to cause substantial convection within the mushy-zone when the solidification rate is approximately 0.001 to 0.0001 cm/s

On Whose Authority?: Linguists\u27 Claim of Expertise to Interpret Statutes

This Article sketches some of the ideas and issues involved in the claims of the Law and Linguistics Consortium and others. It focuses mostly on these linguists\u27 claim of interpretive authority, but also on the particular theory of language that they offer. The question of their claim to objectivity also surfaces later in this essay. On all counts, a single inquiry sums it up: On whose terms have these linguists been authorized

Name Calling: Identifying Stigma in the Civil Union/Marriage Distinction Commentary

The Connecticut marriage equality case, Kerrigan v. Comm’r of Public Health, turns on a threshold determination that the state legislature’s distinction between “civil union” and “marriage” creates a cognizable injury of constitutional dimension. The court’s short explanation of its conclusion hinges on two social facts. First, “marriage” names a long-standing, complex, and revered social institution, while “civil union” is a new name with virtually no history. Second, the “civil union”/“marriage” distinction is framed against a historical background of stereotyping, prejudice, and discrimination against gay men and lesbians. The court’s explanation, while accurate, is all too brief. This Article elaborates some aspects of everyday naming practices involving social identity and kinship, in order to assist us in understanding the injury that comes from mandating two distinct names for the core family relationship. It considers (1) the problem of family identity underlying Juliet’s “What’s in a name” soliloquy in William Shakespeare’s play Romeo and Juliet; (2) Louis Althusser’s concept of interpellation; (3) the feminist critique of language and names, focusing in particular on the “Miss”/“Mrs.”/“Ms.” controversy; and (4) the way in which concrete, diffuse, everyday social practices of naming and recognition are multiscalar, and interact with larger legal and social structures around recognition, dominance, and subordination. With these considerations in mind, it is easier to see that the “civil union”/“marriage” distinction has a cultural meaning that will create a stigmatic injury by reinforcing and activating dormant, dispersed sites of stereotyping and prejudice against gay men and lesbians. Moreover, the distinction will reinforce a preexisting sense of secondclass status, which is arguably a violation of a broad version of a guarantee of dignity under a principle of equal protection. The “civil union”/“marriage” distinction thus involves and facilitates name calling and identifying stigma—just as the Connecticut Supreme Court concluded