A single protein based nanobiosensor for odorant recognition

We propose a nanosensor with a biological active part able to identify specific odorants. The biological part should be constituted by olfactory receptors pertaining to the G protein-coupled receptors, the most efficient natural sensors for odorant discrimination. Modeling, design, and experiments performed for proving the concept are reported and discussed.     

Gravity Force in Capillary Flow Through Open Channels

Certain conditions of superficial properties can provoke spontaneous movement of liquids at corners such as liquid filaments. The understanding of this type of fluid dynamics phenomena is very important in many areas, for example, oil recovery or design of gathering systems of condensed fluids with capillary forces. In previous studies, several models were developed for formation and advancing of filaments at horizontal corners neglecting the gravity force. The objective of this investigation was to provide a mathematical tool to estimate the influence of gravity and to establish a clear approach for taking this effect into account or not. The proposed model is developed from a differential equation applied to an open corner for Poiseuille flow. It provides good agreement with experimental values with a maximum deviation of 3.3%.     

Methane emissions from riverine and swampy coastal wetlands: influence of open and macrophyte‐infested areas

The atmospheric concentration of methane (CH₄) exerts a strong influence on the global climate. Notably, wetlands are important CH₄ sources, whose emission represents an ecosystem process depending on such wetland characteristics as organic matter, temperature, pH, methanogenesis and CH₄ oxidation, all of which vary on the basis of the type of wetland. Methane fluxes were investigated in a preliminary study in the region, using the chamber method in the open water and macrophyte‐infested wetlands of swampy and riverine types in Kilifi, a coastal district in Kenya, Africa. Despite a lack of significant interactions, the macrophyte‐infested areas emitted the highest quantity of methane of about 21.96 ± 0.04 mg CH₄ m^?2 day^?1, compared with the water areas that emitted about 19.35 ± 0.05 mg CH₄ m^?2 day^?1. The preliminary CH₄ fluxes measured in this study are below the range reported from previous wetland field experiments in the tropics and temperate regions, indicating the need to conduct a series of similar experiments to produce more precise total estimates in the entire region.     

Predictive modeling of an energy-absorbing sandwich structural concept using the building block approach

An energy-absorbing composite sandwich structural concept, comprised of a deep honeycomb core with carbon/epoxy facesheets, is subject to through-thickness crushing and penetration using a cylindrical pole. With the aid of the building block approach, the response of the structure is predicted by analysis supported by test evidence. Experiments are conducted at various levels of complexity, from the coupon level used to generate material properties to be used as input in the finite element models, through the element level used to calibrate the analysis models, and up to the component level to validate them. LS-DYNA is used to perform the analyses, including material models MAT 54 for the facesheets, MAT 126 for the honeycomb, and tie-break contact for the adhesive. Material models and contact formulations require extensive calibration of modeling parameters at the lower and intermediate levels of the building block pyramid, but eventually enable the prediction of the full-scale structure.     

Modeling the human knee for assistive technologies

In this paper, we use motion capture technology together with an EMG-driven musculoskeletal model of the knee joint to predict muscle behavior during human dynamic movements. We propose a muscle model based on infinitely stiff tendons and show this allows speeding up 250?times the computation of muscle force and the resulting joint moment calculation with no loss of accuracy with respect to the previously developed elastic-tendon model. We then integrate our previously developed method for the estimation of 3-D musculotendon kinematics in the proposed EMG-driven model. This new code enabled the creation of a standalone EMG-driven model that was implemented and run on an embedded system for applications in assistive technologies such as myoelectrically controlled prostheses and orthoses.     

A Centralized MAC Protocol for QoS Support in UWB-Based Wireless Networks

In this paper we introduce a novel MAC protocol that provides Quality of Service (QoS) support for multimedia traffic in UWB-based wireless local area networks. The proposed protocol allocates transmission opportunities to QoS and best effort traffic using a set of scheduling and resource control algorithms. The algorithms account for the UWB characteristics such as the co-existence of multiple simultaneous transmissions as well as the possibility of dynamically assigning the nodes' transmission rate and power. The simulation results show that the proposed protocol can provide QoS support while optimizing resource utilization. Yuechun Chu received her B.Sc. degree in electrical engineering from Shanghai University, China, in 1996 and M.Sc. degree in electrical engineering from University of Science and Technology of China in 1999. She is currently pursuing the Ph.D. degree in the department of electrical and computer engineering at the University of Massachusetts Amherst. Her research interests include MAC protocol design for UWB-based networks, wireless multimedia applications, and architectures and protocols for wireless networks with QoS guarantees. Aura Ganz is currently an Associate Professor and Director of the Multimedia Networks Laboratory at the ECE Department, University of Massachusetts at Amherst. She has experience in topics related to multimedia wireless networks, optical networks and ubiquitous computing. The research results are validated by a combination of analytical, simulation and prototyping tools. She has published a book “Multimedia Wireless Networks: Technologies, Standards and QoS” (Prentice Hall) and authored over one hundred and fifty peer reviewed publications. Dr. Ganz received her BSc, MSc and Ph.D degrees in Computer Science from the Technion in Israel.     

A percolative simulation of dielectric-like breakdown

Dielectric-like degradation of thin-film conductors is simulated up to final breakdown within a biased percolation model. As relevant indicators we take the damage pattern, current distribution, resistance variation, failure lifetime and relative resistance fluctuations. The results show that biased percolation predicts well several known features taking place close to the abrupt failure of thin films in close agreement with available experimental results.     

Monte Carlo Simulation of Electronic Noise in Semiconductor Materials and Devices Operating under Cyclostationary Conditions

To qualify the feasibility of standard semiconductor materials and Schottky-barrier diodes (SBDs) for THz high-order harmonics generation and extraction, the noise-to-signal ratio is calculated by the Monte Carlo method. Heavily doped GaAs SBDs are found to exhibit conditions for frequency mixing and harmonics extraction which are definitively superior to those of bulk materials.     

Why you shouldn't study security [security education]

A colleague recently mentioned that his son was looking for a PhD program and was considering security as a topic. The immediate reaction from the security researchers present was something to this effect: "No, don't. There are so many other, more interesting things in the world." This might sound like a group of disappointed people, but as far as I know, we all thoroughly enjoy working in the field and by no means regret it as a career choice.