Engineering Commons^™

Collaborative Research: An Integrated Microstructure-Based Approach To Property Prediction For Cement-Based Materials, Eric N. Landis

University of Maine Office of Research Administration: Grant Reports

The project is a collaborative effort between the research groups at the University of Maine and the University of California, Davis. It represents a convergence of 3D micro-structural imaging with discrete element computational modeling to address the need for quantitative links between salient micro-structural properties and bulk material performance. High-resolution 3D images of material microstructure will be produced using x-ray microtomography (XMT). These images will be used to examine the micromechanical response of cement composites to mechanical loading and drying shrinkage. 3D deformation fields and internal crack distributions will be measured at selected loading stages and correlated with the spatial …

Energy Modeling Of Wireless Sensor Nodes Based On Petri Nets, Ali Shareef, Yifeng Zhu

Graduate Student Scholarly and Creative Submissions

Energy minimization is of great importance in wireless sensor networks in extending the battery lifetime. Accurately understanding the energy consumption characteristics of each sensor node is a critical step for the design of energy saving strategies. This paper develops a detailed probabilistic model based on Petri nets to evaluate the energy consumption of a wireless sensor node. The model factors critical components of a sensor node, including processors with emerging energy-saving features, wireless communication components, and an open or closed workload generator. Experimental results show that this model is more flexible and accurate than Markov models. The model provides a …

Sensors: Detecting Microbial Pathogens With Novel Surface Acoustic Wave Devices In Liquid Environments, Mauricio Pereira Da Cunha, Paul J. Millard

University of Maine Office of Research Administration: Grant Reports

This SENSORS proposal integrates research and education to exploit the sensitivity of a new family of LGX crystal devices operated in novel Shear Horizontal Surface Acoustic Wave (SH-SAW) propagation directions by combining them with highly selective molecular padlock probes to detect specific nucleic acid sequences associated with bacteria such as Escherichia coli O157:H7, Salmonella typhi, and Vibrio cholerae in aqueous solutions. The anticipated fundamental advances in sensor science and engineering will be relevant to numerous applications, including rapid response to bioterrorism, healthcare, epidemiology, agriculture, food safety, and pollution avoidance and mitigation.

This SENSORS program builds upon the initial proof-of-concept …

Monitoring Dynamic Spatial Fields Using Responsive Geosensor Networks, Michael Warboys, Silvia Nittel

University of Maine Office of Research Administration: Grant Reports

Many environmental phenomena (e.g., changes in global levels of atmospheric carbon dioxide) can be modeled as variations of attributes over regions of space and time, called dynamic spatial fields. The goal of this project is to provide efficient ways for sensor networks to monitor such fields, and to report significant changes in them. The focus is on "qualitative" changes, such as splitting of areas or emergence of holes in a region of study. The approach is to develop qualitative and topological methods to deal with changes. Qualitative properties form a small, discrete space, whereas quantitative values form a large, continuous …

Sst: Integrated Fluorocarbon Microsensor System Using Catalytic Modification, M. Clayton Wheeler

University of Maine Office of Research Administration: Grant Reports

Selective, sensitive, and reliable sensors are urgently needed to detect air-borne halogenated volatile organic compounds (VOCs). This broad class of compounds includes chlorine, fluorine, bromine, and iodine containing hydrocarbons used as solvents, refrigerants, herbicides, and more recently as chemical warfare agents (CWAs). It is important to be able to detect very low concentrations of halocarbon solvents and insecticides because of their acute health effects even in very low concentrations. For instance, the nerve agent sarin (isopropyl methylphosphonofluoridate), first developed as an insecticide by German chemists in 1938, is so toxic that a ten minute exposure at an airborne concentration of …

Contract Documents For Earleys Bridge Substructure Replacement In The Town Of Willimantic, Maine, Calderwood Engineering, Etc., Eric T. Calderwood

Maine Town Documents

No abstract provided.