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Analysis Of Solid-Liquid Phase Change Under Pulsed Heating, S. Krishnan, J. Y. Murthy, S V. Garimella

CTRC Research Publications

Solid/liquid phase change occurring in a rectangular container with and without metal foams subjected to periodic pulsed heating is investigated. Natural convection in the melt is considered. Volume-averaged mass and momentum equations are employed, with the Brinkman–Forchheimer extension to Darcy’s law used to model the porous resistance. A local thermal nonequilibrium model, assuming equilibrium melting at the pore scale, is employed for energy transport through the metal foams and the interstitial phase change material (PCM). Separate volumeaveraged energy equations for the foam and the PCM are written and are closed using a heat transfer coefficient. The enthalpy method is employed …

Numerical And Experimental Investigation Of Solidification Shrinkage, D. Sun, S V. Garimella

CTRC Research Publications

The solidification heat transfer, melt convection, and volume shrinkage in the casting of an energetic material are analyzed through numerical modeling and experimental investigation. The shrinkage resulting from phase change is considered through the volume-of-fluid method. The model is validated against an analytical solution and then applied to study the volume contraction during the casting of trinitrotoluene (TNT). Good agreement is obtained between experimental results and predictions of temperatures at selected locations as well as shrinkage shape. New casting conditions are suggested based on the analysis, and improved results are observed both numerically and experimentally.

Correlation Energy In A Spin-Polarized Two-Dimensional Electron Liquid In The High-Density Limit, S. Chesi, G. F. Giuliani

Department of Physics and Astronomy Faculty Publications

We have obtained an analytic expression for the ring diagram contribution to the correlation energy of a two-dimensional electron liquid as a function of the uniform fractional spin polarization. Our results can be used to improve the interpolation formulas which represent the basic ingredient for the construction of modern spin-density functionals in two dimensions.

Single Spike Solutions For Strings On S-2 And S-3, R. Ishizeki, M. Kruczenski

Department of Physics and Astronomy Faculty Publications

We study solutions for rigidly rotating strings on a two-sphere. Among them we find two limiting cases that have a particular interest, one is the already known giant magnon and the other we call the single spike solution. The limiting behavior of this last solution is a string infinitely wrapped around the equator. It differs from that solution by the existence of a single spike of height (theta) over bar that points toward the north pole. We study its properties and compute its energy E and angular momentum J as a function of (theta) over bar. We further generalize the …

Bond-Propagation Algorithm For Thermodynamic Functions In General Two-Dimensional Ising Models, Y. L. Loh, E. W. Carlson, M. Y. J. Tan

Department of Physics and Astronomy Faculty Publications

Recently, we developed and implemented the bond-propagation algorithm for calculating the partition function and correlation functions of random-bond Ising models in two dimensions [Y. L. Loh and E. W. Carlson, Phys. Rev. Lett. 97, 227205 (2006)]. The algorithm is the fastest available for calculating these quantities near the percolation threshold. In this paper, we show how to extend the bond-propagation algorithm to directly calculate thermodynamic functions by applying the algorithm to derivatives of the partition function and we derive explicit expressions for this transformation. We also discuss variations of the original bond-propagation procedure within the larger context of Y del …

Quantum Phase Transition In The Quantum Compass Model, H. D. Chen, C. Fang, J. P. Hu, H. Yao

Department of Physics and Astronomy Faculty Publications

In this work, we show that the quantum compass model on a square lattice can be mapped to a fermionic model with local-density interaction. We introduce a mean-field approximation where the most important fluctuations, those perpendicular to the ordering direction, are taken into account exactly. It is found that the quantum phase transition point at J(x)=J(z) marks a first-order phase transition. We also show that the mean-field result is robust against the remaining fluctuation corrections up to the second order.

Current And Future Status Of Chemistry Collections And Chemistry Libraries At Arl Institutions, Jeremy R. Garritano

Libraries Research Publications

The process of consolidating science and technology branch libraries in academic institutions is not new, but with ease of access to electronic resources, and with shrinking budgets and interdisciplinary research the norm, the idea of consolidation has become more attractive in the past decade. This article reports on the results of a 2005 survey of Association of Research Libraries (ARL) institutions and the status of their chemistry-related library resources and facilities. The past, present, and future of these chemistry collections will be discussed with emphasis on those having consolidated in the last ten years or those who plan to consolidate …

William Freeman Myrick Goss Library Of The History Of Engineering, Sammie L. Morris

Libraries Research Publications

An essay profiling the history, development, and strengths of the William Freeman Myrick Goss Library of the History of Engineering at Purdue University Libraries. General information on special collections holdings of the Purdue University Libraries is also included.

Biopoem, Wongsakorn Chanseawrassamee

Journal of Southeast Asian American Education and Advancement

No abstract provided.

Influence Of Speed Limits On Roadway Safety In Indiana, Nataliya V. Malyshkina, Fred L. Mannering, Samuel Labi

JTRP Technical Reports

The influence of speed limits on roadway safety is an extremely important social issue and is subject to an extensive debate in the State of Indiana and nationwide. With roughly 900 fatalities and sixty thousand injuries annually in Indiana, traffic accidents place an incredible social and economic burden on the state. Still, speed limits posted on highways and other roads are routinely exceeded as individual drivers try to balance safety and mobility (speed) as well as risks of penalties from enforcement efforts. This research explores the relationship between speed limits and roadway safety. Specifically, the research focuses on the influence …

Deriving The Cost Impacts Of Indiana's Storm Water Rule 13 On Indot Maintenance Facility Operations, Lynn A. Corson

JTRP Technical Reports

The objectives of this research were: 1. To classify maintenance facilities by ten or fewer “typologies” (categories) to analyze storm water collection and drainage from the sites and to estimate the cost of installing or implementing Best Management Practices (BMPs), identified by INDOT, to prevent or reduce contamination of the drainage that migrates to waters of the state; 2. To prepare an Environmental Management System (EMS) modeled on the ISO 14001 Standard and “pilot” the EMS in an INDOT District; conduct EMS Awareness training for affected employees. The research included the conduct of on-site operations and environmental assessments at 50 …

Safety Conscious Planning In Indiana: Predicting Safety Benefits In Corridor Studies, Volume 1: Research Report, Andrzej P. Tarko, Muhammad Asif Iqbal, Michal Adam Inerowicz, Hong Liang, Gopal Panicker

JTRP Technical Reports

INDOT units responsible for planning and pre-engineering analysis consider safety implications of studied alternative roadway and road network solutions to the extent allowed by the available tools. This project is meant to enhance the available tools of predicting crash frequencies in future road networks to improve the quality of safety consideration in intermediate and long-term road planning.

Safety Performance Functions are widely used to estimate and predict road safety at intersections and on segments. Evaluation of the performance of the functions developed for regions other than Indiana indicated that only full recalibration, which is in fact equivalent to developing own …

Sisters In Science: Conversations With Black Women Scientists On Race, Gender, And Their Passion For Science, Diann Jordan

Purdue University Press Books

Author Diann Jordan took a journey to find out what inspired and daunted black women in their desire to become scientists in America. Letting 18 prominent black women scientists talk for themselves, Sisters in Science becomes an oral history stretching across decades and disciplines and desires. From Yvonne Clark, the first black woman to be awarded a B.S. in mechanical engineering to Georgia Dunston, a microbiologist who is researching the genetic code for her race, to Shirley Jackson, whose aspiration led to the presidency of Rensselaer Polytechnic Institute, Jordan has created a significant record of women who persevered to become …

Novel Evolutionary Global Optimization Algorithms And Their Applications, Hualin Wang, Okan Ersoy

Department of Electrical and Computer Engineering Technical Reports

The gray code optimization (GCO) algorithm is a deterministic global optimization algorithm based on integer representation. It utilizes the adjacency property of Gray code representation. By controlling the number of bits flipped, it searches through the space effciently. A further development of the GCO algorithm is conducted in this research to avoid getting stuck in local minima. To further improve the performance, and take the advantage of cheaper but more powerful CPUs, a parallel computation paradigm using MPI is implemented. Analysis of the mechanism of the GCO algorithm indicated that it can be modeled by mixture gaussian. This led to …

Realizing Privacy-Preserving Features In Hippocratic Databases, Yasin Laura-Silva, Walid G. Aref

Department of Computer Science Technical Reports

No abstract provided.

Traveling Salesman Problem: A Foveating Pyramid Model, Zygmunt Pizlo, Emil Stefanov, John Saalweachter, Zheng Li, Yll Haxhimusa, Walter G. Kropatsch

The Journal of Problem Solving

We tested human performance on the Euclidean Traveling Salesman Problem using problems with 6–50 cities. Results confirmed our earlier findings that: (a) the time of solving a problem is proportional to the number of cities, and (b) the solution error grows very slowly with the number of cities. We formulated a new version of a pyramid model. The new model has an adaptive spatial structure, and it simulates visual acuity and visual attention. Specifically, the model solves the E-TSP problem sequentially by moving attention from city to city, the same way human subjects do. The model includes a parameter representing …

Perceptual Or Analytical Processing? Evidence From Children's And Adult's Performance On The Euclidean Traveling Salesperson Problem, Iris Van Rooij, Alissa Schactman, Helena Kadlec, Ulrike Stege

The Journal of Problem Solving

The Euclidean Traveling Salesperson Problem (E-TSP) is a useful task to study how humans optimize when faced with computational intractability. It has been found that humans are capable of finding high-quality solutions for E TSP in a relatively short time and with seemingly little cognitive effort. This observation has led to two general proposals: The high quality of performance on E-TSP reflects (a) the output of automatic and innate perceptual processes or (b) a fundamentally intelligent approach to the task by humans. An experiment was performed to compare performance of three age groups (7- year-olds, 12-year-olds, and adults). Our findings …

A Comparison Of Heuristic And Human Performance On Open Versions Of The Traveling Salesperson Problem, James N. Macgregor, Edward P. Chronicle, Thomas C. Ormerod

The Journal of Problem Solving

We compared the performance of three heuristics with that of subjects on variants of a well-known combinatorial optimization task, the Traveling Salesperson Problem (TSP). The present task consisted of finding the shortest path through an array of points from one side of the array to the other. Like the standard TSP, the task is computationally intractable and, as with the standard TSP, people appear to be able to find good solutions with relative ease. The three heuristics used mechanisms that have been cited as potentially relevant in human performance in the standard task. These were: convex hull, nearest neighbor, and …

Are Individual Differences In Performance On Perceptual And Cognitive Optimization Problems Determined By General Intelligence?, Nicholas R. Burns, Michael D. Lee, Douglas Vickers

The Journal of Problem Solving

Studies of human problem solving have traditionally used deterministic tasks that require the execution of a systematic series of steps to reach a rational and optimal solution. Most real-world problems, however, are characterized by uncertainty, the need to consider an enormous number of variables and possible courses of action at each stage in solving the problem, and the need to optimize the solution subject to multiple interacting constraints. There are reliable individual differences in people’s abilities to solve such realistic problems. It also seems likely that people’s ability to solve these difficult problems reflects, or depends on, their intelligence. We …

Contents

The Journal of Problem Solving

No abstract provided.

Compressed Text Indexing And Range Searching, Yu-Feng Chien, Wing-Kai Hon, Rahul Shah, Jeffrey S. Vitter

Department of Computer Science Technical Reports

No abstract provided.

An Ocean View Of The Early Cenozoic Greenhouse World, Ellen Thomas, Henk Brinkhuis, Matthew Huber, Ursula Röhl

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

No abstract provided.

Portrayal Of Mathematicians In Fictional Works, Daniel Dotson

CLCWeb: Comparative Literature and Culture

In his article "Portrayal of Mathematicians in Fictional Works," Daniel Dotson explores how people with mathematical abilities -- including mathematicians, mathematics teachers, mathematically-inclined youths, cryptographers, and more -- are portrayed in novels, films, television programs, and a play. A summary table of the characters gives a short description of each of them, the title of the work in which they appeared, and the format of the work. Characters were analyzed to see if they possessed any of ten personality traits: obsessive, having major mental health problems, withdrawn, brave, timid, socially inept, arrogant, uses math to escape reality, out of touch, …

Place*: A Distributed Spatio-Temporal Data Stream Management System For Moving Objects, Xiaopeng Xiong, Hicham G. Elmongui, Xiaoyong Chai, Walid G. Aref

Department of Computer Science Technical Reports

No abstract provided.

The Effectiveness Of Problem-Based Instruction: A Comparative Study Of Instructional Methods And Student Characteristics, John R. Mergendoller, Nan L. Maxwell, Yolanda Bellisimo

Interdisciplinary Journal of Problem-Based Learning

This study compared the effectiveness of problem-based learning (PBL) and traditional instructional approaches in developing high-school students’ macroeconomics knowledge and examined whether PBL was differentially effective with students demonstrating different levels of four aptitudes: verbal ability, interest in economics, preference for group work, and problem-solving efficacy. Over all, PBL was found to be a more effective instructional approach for teaching macroeconomics than traditional lecture–discussion (p = .05). Additional analyses provided evidence that PBL was more effective than traditional instruction with students of average verbal ability and below, students who were more interested in learning economics, and students who were most …

The Effect Of A Problem-Centered, Enculturating Experience On Doctoral Students’ Self-Efficacy, Joanna C. Dunlap

Interdisciplinary Journal of Problem-Based Learning

Preparing students to be effective leaders in their organizational and professional settings is a common goal of leadership preparation programs. However, students often lack confidence to share their knowledge and expertise in public forums. This study addressed whether the use of the rich environments for active learning (REAL) instructional model increased students’ self-efficacy regarding contributing to the professional community of practice through scholarship (i.e., research and study) and publication. Twelve doctoral students preparing to be educational leaders published an online journal. This study demonstrated how engaging students in problem-centered, enculturating activities that reflected the true nature of educational leadership and …

Perceptions Of The Value Of Problem-Based Learning Among Students With Special Needs And Their Teachers, Brian R. Belland, Peggy A. Ertmer, Krista D. Simons

Interdisciplinary Journal of Problem-Based Learning

While problem-based learning (PBL) has been found to be effective with gifted and average students (Hmelo-Silver, 2004), little is known about its impact on students with special needs. This study examines the perceptions of middle-school students with mild, moderate, and severe disabilities and of their teachers regarding the value of participating in a PBL unit. The unit focused on the physical accessibility of a low-SES, rural community where the students’ school was located.We used the constant comparative method (Glaser & Strauss, 1967) to analyze interview data, and used observation data and artifacts to triangulate interview comments. Among the noteworthy findings …

Advances In Mesoscale Thermal Management Technologies For Microelectronics, Suresh Garimella

Other Nanotechnology Publications

This paper presents recent advances in a number of novel, high-performance cooling techniques for emerging electronics applications Critical enabling thermal management technologies covered include microchannel transport and micropumps, jet impingement, miniatur flat heat pipes, transient phase change energy storage systems, piezoelectric fans, and prediction of interface contact conductance. (c) 2005 Elsevier Ltd. All rights reserved.

Slam: Sleep-Wake Aware Local Monitoring In Sensor Networks, Issa Khalil, Saurabh Bagchi, Ness B. Shroff

Department of Electrical and Computer Engineering Technical Reports

Sleep-wake protocols are critical in sensor networks to ensure long-lived operation. However, an open problem is how to develop efficient mechanisms that can be incorporated with sleep-wake protocols to ensure both longlived operation and a high degree of security. Our contribution in this paper is to address this problem by using local monitoring, a powerful technique for detecting and mitigating control/data attacks in sensor networks. In local monitoring, a node oversee part of the traffic going in and out of its neighbors to determine if the behavior is suspicious, such as, delay in forwarding a packet. However, a direct application …

Energy-Efficient Distributed Consturctions Of Minimum Spanning Tree For Wireless Ad-Hoc Networks, Maleq Khan, Gopal Pandurangan, V. S. Anil Kumar

Department of Computer Science Technical Reports

No abstract provided.