Lab-on-a-chip workshop activities for secondary school students

The ability to engage and inspire younger generations in novel areas of science is important for bringing new researchers into a burgeoning field, such as lab-on-a-chip. We recently held a lab-on-a-chip workshop for secondary school students, for which we developed a number of hands-on activities that explained various aspects of microfluidic technology, including fabrication (milling and moulding of microfluidic devices, and wax printing of microfluidic paper-based analytical devices, so-called μPADs), flow regimes (gradient formation via diffusive mixing), and applications (tissue analysis and μPADs). Questionnaires completed by the students indicated that they found the workshop both interesting and informative, with all activities proving successful, while providing feedback that could be incorporated into later iterations of the event

RAINBOW TRAPPING EFFECT IN 2D AXISYMMETRIC BROADBAND ACOUSTIC ENERGY HARVESTERS

Acoustic energy harvesters (AEHs) collect otherwise unused ambient acoustic waves for conversion into useful electrical energy. This promising technology has potential applications ranging from grid-independent electronics to structural health monitoring systems. AEHs capture specific acoustic frequencies of interest using structures with frequency-matched component geometries. Despite the multitude of potential geometries suitable for AEH structures, existing AEH research has predominantly focused on the acoustic wave trapping performance of unidimensional or linear bidimensional AEH structures. This study intended to broaden AEH bandwidth and capture efficiency by investigating the acoustic rainbow trapping performance of a novel 2D axisymmetric AEH design. A Finite Element Method (FEM) approach was employed using COMSOL Multiphysics® v5.5 to evaluate the acoustic wave trapping performance of various groove, cylindrical pillar, and circular hole-based unit cell geometries across the 100 kHz - 220 kHz frequency range. The grooved unit cell groove/plate depth ratio and overall plate depth were optimized. A FEM simulation analyzed the acoustic rainbow trapping performance of a 2D axisymmetric AEH design comprised of a gradient array of these optimized unit cells. These FEM results were validated using an array of piezoMEMS sensors mounted to an aluminum AEH prototype. The prototype displayed reliably predictable acoustic frequency trapping at defined locations. Through these results, this study demonstrated the viability of 2D axisymmetric AEHs in enhancing the acoustic rainbow trapping effect across a broadband frequency range of interest. However, there is much opportunity to refine this AEH design. This proof of concept presents a strong impetus for furthering 2D axisymmetric AEH research

Git as an Encrypted Distributed Version Control System

This thesis develops and presents a secure Git implementation, Git Virtual Vault (GV2), for users of Git to work on sensitive projects with repositories located in unsecure distributed environments, such as in cloud computing. This scenario is common within the Department of Defense, as much work is of a sensitive nature. In order to provide security to Git, additional functionality is added for confidentiality and integrity protection. This thesis examines existing Git encryption implementations and baselines their performance compared to unencrypted Git. Real-world Git repositories are examined to characterize typical Git usage and determine if the existing Git encryption implementations are capable of efficient performance with regards to typical Git usage. This research shows that the existing Git encryption implementations do not provide efficient performance. This research develops an improved secure Git implementation, GV2, with transparent authenticated encryption. The fundamental contribution of this research is developing GV2 to perform Git garbage collection on plaintext data before encrypting the data. The result is a secure Git implementation that is transparent to the user with only a minor performance penalty, compared to unencrypted Git

Coupling Ground Penetrating Radar Applications with Continually Changing Decomposing Human Remains

Locating the clandestine burial of human remains has long perplexed law enforcement officials involved in crime scene investigations, and continues to bewilder all the scientific disciplines that have been incorporated into their search and recovery. Locating concealed human remains can often be compared to the proverbial search for a needle in the haystack. Many notable forensic specialists and law enforcement agencies, in an effort to alleviate some of the bewilderment that commonly accompanies the search for a buried body, suggest that multidisciplinary search efforts are becoming more of a necessity, and less of an option. Research at the University of Tennessee’s Anthropological Research Facility (ARF) in Knoxville supports this theory through a collaborative research effort directed toward the development of more efficient and effective methods in the search for, and detection of, buried human remains. The Department of Anthropology, in conjunction with the University’s Department of Biosystems Engineering and Environmental Science, has correlated the use of ground penetrating radar (GPR) with postmortem processes of decomposing human targets. Two and three dimensional imagery programs were utilized to optimize the analysis and interpretation of the data acquired over the past eight months. The processed images were then compared to models of human decompositional stages. The results of this research support and acknowledge that GPR is only capable of enhancing field methods in the search for clandestine burials, and when coupled with target-specific geophysical imagery software, contributes valuable working knowledge in regards to the contents of the burial itself. Hence, such resources can only be seen as beneficial to a search teams’ endeavors

NASA Tech Briefs, February 1996

Topics covered include: Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Reports

NASA Tech Briefs, December 1999

Topics include: Imaging/Videos/Cameras; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Books and Reports

Upper Paleozoic to Lower Mesozoic Tetrapod Ichnology Revisited : Photogrammetry and Relative Depth Pattern Inferences on Functional Prevalence of Autopodia

In recent years photogrammetry has become an essential tool in the study of tetrapod footprints. Morphological analyses of footprints are interpretative; thus, researchers should use as much information as possible in order to eventually provide an objective conclusion. In this regard, photogrammetry is an extremely helpful tool to avoid potential biases and to better present ichnological data. We review the use of this technique in several Permian and Triassic tetrapod ichnological studies, with considerations on (1) ichnotaxonomy, (2) track-trackmaker correlation, (3) locomotion and/or behavior, (4) substrate induced effects, and (5) preservation of the fossil record and heritage. Furthermore, based on the available three-dimensional (3D) data on Permian and Triassic material, we present a first qualitative interpretation of relative depth patterns and the related functional prevalence (most deeply impressed area) within footprints. We identified three main groups: (1) anamniote, captorhinomorph/parareptile tracks (medial-median functional prevalence), (2) diapsid tracks (median functional prevalence), and (3) synapsid tracks (median-lateral functional prevalence). The use of 3D photogrammetric models brings new light to the tetrapod footprint record, helping to better understand tetrapod communities throughout the late Paleozoic (and the end-Guadalupian and end-Permian extinctions) and the tetrapod recovery during the early Mesozoic