Engineering Commons^™

Angular Momentum In Human Walking, Marko Popovic, Hugh Herr

Marko B. Popovic

Angular momentum is a conserved physical quantity for isolated systems where no external moments act about a bodyʼs center of mass (CM). However, in the case of legged locomotion, where the body interacts with the environment (ground reaction forces), there is no a priori reason for this relationship to hold. A key hypothesis in this paper is that angular momentum is highly regulated throughout the walking cycle about all three spatial directions [ (t) ≈0], and therefore horizontal ground reaction forces and the center of pressure trajectory can be explained predominantly through an analysis that assumes zero net moment about …

The Direct Patterning Of Nanoporous Interlayer Dielectric Insulator Films By Nanoimprint Lithography, Alamgir Karim

Alamgir Karim

No abstract provided.

Does Faculty Research Improve Undergraduate Teaching: An Analysis Of Existing And Potential Synergies, Michael Prince, R. Felder, R. Brent

Michael J. Prince

No abstract provided.

A Canonical Seed Assignment Model For Key Predistribution In Wireless Sensor Networks, Patrick Tague, Radha Poovendran

Patrick Tague

A promising solution for trust establishment in wireless sensor networks is the assignment of cryptographic seeds (keys, secrets, etc.) to sensor nodes prior to network deployment, known as key predistribution. In this article, we propose a canonical seed assignment model for key predistribution characterizing seed assignment in terms of the probability distribution describing the number of nodes receiving each seed and the algorithm for seed assignment. In addition, we present a sampling framework for seed assignment algorithms in the canonical model. We propose a probabilistic k-connectivity model for randomly deployed secure networks using spatial statistics and geometric random graph theory.We …

Optimal Roughness For Minimal Adhesion, Nancy Burnham, D-L Liu, J Martin

Nancy A. Burnham

Roughness has a significant affect on adhesion. The authors used a single-asperity model to describe a smooth tip in contact with a rough surface and predicted that an optimal size of asperity yields a minimum of adhesion. Experimentally, adhesive forces on silicon wafers with varying roughness were measured using atomic-force-microscopy cantilevers with varying tip radii. It was found that minima do exist, and for all tip radii, the adhesion falls significantly for roughness greater than 1–2nm and drops at higher roughness for larger tips. This work should help minimize stiction in microelectromechanical systems and progress the understanding of nanoscale-contact mechanics.

Tailed Forisomes Of Canavalia Gladiata: A New Model To Study Ca2+-Driven Protein Contractility, Winfried Peters, Michael Knoblauch, Stephen Warmann, Reinhard Schnetter, Amy Shen, William Pickard

Winfried S. Peters

Simulations Of Bubble Column Reactors Using A Volume Of Fluid Approach: Effect Of Air Distributor, Abid Akhtar

Abid Akhtar Mr

Two- and three-dimensional numerical simulations have been performed on a laboratory scale bubble column reactor using a volume-of-fluid approach. The effect of hole-size and superficial gas velocity on the bubble size distribution and their trajectories has been investigated on a 20 cm diameter and 1 m high cylindrical reactor. All simulations were performed in a transient manner using a FLUENT solver. Surface tension between two phases has been modelled as a body force with a constant value. Turbulence was modelled using the k-(epsilon) turbulence approach. A comparison between simulation predictions and the reported experimental studies has shown a good agreement.

The Ibm Rational Unified Process For System Z, Or Making Development On System Z More Agile, Cécile Péraire, Mike Mike Edwards, Angelo Fernandes, Enrico Mancin, Kathy Carroll

Cécile Péraire

No abstract provided.

The Influence Of Amino Acid Sequence And Functionality On The Binding Process Of Peptides Onto Gold Surfaces, Gustavo Carri

Gustavo A. Carri

We present a molecular dynamics study of the binding process of peptide A3 (AYSSGAPPMPPF) and other similar peptides onto gold surfaces, and identify the functions of many amino acids. Our results provide a clear picture of the separate regimes present in the binding process: diffusion, anchoring, crawling and binding. Moreover, we explored the roles of individual residues. We found that tyrosine, methionine, and phenylalanine are strong binding residues; serine serves as an effective anchoring residue; proline acts as a dynamic anchoring point, while glycine and alanine give flexibility to the peptide backbone. We then show that our findings apply to …

The Many Faces Of Inductive Teaching And Learning, Michael Prince, R. Felder

Michael J. Prince

No abstract provided.

A Roadmap To Method Development, Cécile Péraire

Cécile Péraire

No abstract provided.

3d Thoracoscopic Ultrasound Volume Measurement Validation In An Ex Vivo And In Vivo Porcine Model Of Lung Tumours, V. Hornblower, E. Yu, A. Fenster, J. Battista, R. Malthaner

Edward Yu

The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial "tumours" were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the "tumours" were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the …

The Ibm Rational Unified Process For System Z, Cécile Péraire, Mike Edwards, Angelo Fernandes, Enrico Mancin, Kathy Carroll

Cécile Péraire

No abstract provided.

The Difficulty Factors Approach To The Design Of Lessons In Intelligent Tutor Curricula, Ryan Baker, Albert Corbett, Kenneth Koedinger

Ryan S.J.d. Baker

We present an approach to designing intelligent tutoring systems, termed the Difficulty Factors Approach. In this approach, the designer investigates, at each iteration of the design cycle, which skills and concepts are difficult for students, and what factors underlie those difficulties. We show that this approach complements existing design principles, producing data that helps designers apply principles in context. We also show that by continuing to investigate student difficulties throughout the design process, it is possible to discover difficulty factors initially obscured by other difficulty factors. We give an example of the application of the Difficulty Factors Approach in the …

Enhancing Design Learning Using Groupware, Andrew Wodehouse, Ozgur Eris, Hillary Grierson, Ade Mabogunje

Ozgur Eris

Project work is increasingly used to help engineering students integrate, apply and expand on knowledge gained from theoretical classes in their curriculum and expose students to `real world' tasks. To help facilitate this process, the department of Design, Manufacture and Engineering Management at the University of Strathclyde has developed a web-based groupware product called LauLima to help students store, share, structure and apply information when they are working in design teams. This paper describes a distributed design project class in which LauLima has been deployed in accordance with a Design Knowledge Framework that describes how design knowledge is generated and …