Finite element analysis of nonisothermal polymer processing operations

A finite element formulation for the analysis of polymer processing is presented and its use in some typical situation including entry flow, transient Couette flow, and the Graetz (forced convection) problem is illustrated. The element formulations are constructed on the premise that momentum convection can be neglected (polymer melt flows typically have very low Reynolds' numbers), but that convective heat transfer may be significant (high Peclet numbers). Nonisothermal effects are considered important in polymer processing, due in part to the significant heating which may occur due to viscous dissipation, and also to the very strong influence of temperature on fluid viscosity. The flow is treated as Newtonian with the flow field being coupled to the heat transfer equation only through the viscous heat generation

Chemorheology of reactive systems: Finite element analysis

The equations which govern the nonisothermal flow of reactive fluids are outlined, and the means by which finite element analysis is used to solve these equations for the sort of arbitrary boundary conditions encountered in industrial practice are described. The performance of the computer code is illustrated by several trial problems, selected more for their value in providing insight to polymer processing flows than as practical production problems. Although a good deal remains to be learned as to the performance and proper use of this numerical technique, it is undeniably useful in providing better understanding of today's complicated polymer processing problems

BS-ISO helical gear fatigue life estimation and wear quantitative features analysis

Original article can be found at: http://www3.interscience.wiley.com/ Copyright Blackwell Publishing. DOI: 10.1111/j.1475-1305.2008.00457.xLack of representative theoretical models for gear wear causes difficulties in their useful lifetime prediction. Critical operating parameters, such as loading and lubrication, affect the wear process in a very complex manner and lead the theoretical modelling to an imperfect zone of assumptions. Complexities in gear wear mathematical modelling allow the researchers to use approximations for useful lifetime calculations. On the basis of modelling approximations and assumptions, organizations, such as American Gear Manufacturers' Association (AGMA) and British Standards (BS), provide gear useful lifetime formulations. In these formulations, the useful lifetime values are estimated by means of experimentation that is controlled with known gear operating conditions and physical dimensions. However, for useful lifetime estimation and validation, these standards have not considered any experimental approach that represents the actual gear wear. In this paper, an effort is made to validate the competency of standard's gear useful lifetime formulation. For this purpose, an approach that is able to provide an idea about actual gear wear is used. During the effort, BS-ISO 6336-2 standard formulation is used for helical gear useful lifetime estimation under linear pitting fatigue conditions. The used formulation is validated by using wear quantitative feature analysis that is able to provide actual gear wear quantitative trends. The obtained wear quantitative trends fairly validate the lifetime estimation of BS-ISO 6336-2 standard.Peer reviewe

Merging Illustrations and Printing on Big Paper

How to guide for some of the printing utilities in the AI lab. Describes how TEX tiles are processed and how some illustrations may be merged into the final copy. Also describes how to use TEX to print on 8.5x14 (legal) and 11x17 size paper.MIT Artificial Intelligence Laborator

Developing a Labor Epidural Information Course for First Time Mothers

In the field of anesthesia, an epidural is the most common fonn of analgesia for laboring mothers. Legally, in order for an anesthesia provider to place an epidural, the parturient must be educated regarding this form of analgesia. Most anesthesia providers do educate their patients regarding epidurals. However, several problems arise with current procedures including a majority of the education taking place while the mother is in labor and being provided by someone other than anesthesia personnel. These problems pose questions such as: (A) ls this the most efficacious time to educate expecting mothers, (B) Does the parturient truly understanding the risks and benefits of epidural analgesia, and (C) Who should be providing this education? The plan for this project will be to develop an antenatal educational course for expectant mothers using power point presentation as well as visual aids. The course will discuss labor analgesic techniques with its core focus on epidurals. An anesthesia provider will also explain the goals, benefits, risks and complications of epidural analgesia Anticipated results of this project will be to provide appropriate education to expectant mothers at a better time and under conditions that are more comfortable. The women completing this course will understand both positive and negative aspects of choosing an epidural for labor as well as have an opportunity to ask questions. Another wonderful benefit with this timely education will be a decreased amount of anxiety felt by parturients as they enter the hospital on that special da

Numerical analysis of projectile impact in woven texile structures

Computer codes were developed for simulating the dynamic fracture and viscoelastic constitutive response due to stress wave interaction and reflections caused by ballistic impact on woven textiles. The method, which was developed for use in the design and analysis of protection devices for personnel armor, has potential for use in studies of rotor blade burst containment at high velocity. Alterations in coding required for burst containment problems are discussed

Treating Objects like Women: The Impact of Terror Management and Objectification on the Perception of Women's Faces

According to terror management theory, humans are threatened by the awareness of death and counter this threat by investing in cultural systems that make them feel like they are more than mortal animals. Based on this proposition, it has been argued that women's bodies pose a unique existential threat, as they remind humans of their similarity to other biological organisms. However, no research thus far has examined how death awareness impacts perceptual assessments of women. The current study examined the effect of heightened death-awareness on perceptions of women's faces, utilizing face-morphing techniques that create a range of artificial-to-real faces. Results indicated that following a death-awareness induction, participants perceived artificial female faces as less artificial, but not necessarily more attractive. MS did not predict perceptions of male faces. These results suggest that existential concerns about death have an impact on perceptual assessments of women

Finite element modeling of nonisothermal polymer flows

A finite element formulation designed to simulate polymer melt flows in which both conductive and convective heat transfer are important is described, and the numerical model is illustrated by means of computer experiments using extruder drag flow and entry flow as trial problems. Fluid incompressibility is enforced by a penalty treatment of the element pressures, and the thermal convective transport is modeled by conventional Galerkin and optimal upwind treatments