Forensic anthropologists normally examine bone from a variety of medicolegal contexts. The skeletal remains may in some cases be highly fragmented or taphonomically modified, making it difficult to sort bone from non-bone material. In these cases, the forensic anthropologist may rely on microscopic or destructive chemical analyses to sort the material. However, these techniques are costly and time-intensive, prompting the use of nondestructive analytical methods in distinguishing bone and teeth from non-bone materials in a limited number of cases. The proposed analytical techniques are limited in that they rely on an examination of the major elements in the material, and do not sort out all materials with a similar chemical composition to bone/teeth. To date, no methods have been proposed for the use of handheld Xray fluorescence (HHXRF) spectrometry in discriminating human and nonhuman bone/teeth from non-bone materials. The purpose of this research was to develop a method for the use of HHXRF spectrometry in forensic anthropology specifically related to distinguishing human and nonhuman bone and teeth from non-bone materials of a similar chemical composition using multivariate statistical analyses: principal components analysis (PCA), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), and hierarchical cluster analysis (HCA). This was accomplished in two phases. Phase 1 consisted of a Reliability Test and involved sampling a single human long bone in thirty locations. Multiple spectra were collected at each location to examine the reliability of the instrument in detecting the elements both within a single site and between multiple sites. The results of the Reliability Test indicated that HHXRF consistently detected the major and minor elements found on the surface of a human bone. iv These results were used for Phase 2, designated the Accuracy Test, which involved analyzing a set of materials compiled from the literature to test the accuracy of the technique in discriminating bone (human and nonhuman) and non-bone samples (other biological and nonbiological). The results of the Accuracy Test indicate that osseous and dental tissue can be distinguished from non-bone material of similar chemical composition with a high degree of accuracy (94%) when data is collected from several locations on a sample and analyzed separately during multivariate statistical analyses. Overall, it was not possible to discriminate rock apatite and synthetic hydroxyapatite (synthetic bone) from bone. However, this technique successfully discriminated other non-bone materials that are chemically similar to bone, such as ivory and octocoral, which previous methods focusing on only a comparison of Ca/P ratios were unable to distinguish from bone.

Distance education is the fastest growing educational modality because of advances information technology has made over the past 25 years. Adult learners have become the fastest growing population in distance education. Adult learners, through technical tools and devices they use on the job, have become more digitally literate and mobile, making the ability to access class work on the go a necessity. Mobile learning or m-learning (learning that uses wireless, portable, mobile computing, and communication devices) is becoming an extension of distance learning, providing a channel for students to learn, communicate, and access educational material outside the traditional classroom environment. For adult learners, this modality allows them to take advantage of accessing material using mobile devices they use for job related activities. Despite the portability and readiness to information mobile devices provide its users, cognitive and physical ergonomic issues may impact learner performance. These issues may stem from information overload and physical discomfort from extended use of the mobile device which may negatively affect the overall success and satisfaction of m-learning environments. The purpose of this study was to examine the relationship between physical ergonomic discomfort, subjective workload, physiological response, and the impact on student performance while using mobile technology to read course material. Activity Theory was used as the theoretical foundation that guided the study. Eighty-four research participants, all over the age of 25, read a passage using one of two distance education modalities: desktop computer or mobile device. While reading the passage, one of three task load levels was imposed on participants: none, low or high. Each participant endured three trials, repeating the same task for each trial. After each trial, participants completed an achievement test and the NASA-TLX assessment. The results from this study provided evidence that mobile learning technologies with increased levels of task load introduced physical ergonomic discomfort and affected perceptions of mental workload in participants. The study also provided evidence that mobile learning technologies with increased levels of task load affected the performance (reading and learning) of participants. Study results provided insight into capabilities and limitations of students in their use of mobile devices for educational purposes. The limitations identified need to be further examined to aid in building successful m-learning environments with the goal of mobile device usage not affecting student performance.

The intent of this thesis is to analyze obsidian artifacts from Chiquiuitan, Guatemala to see if the samples can be traced to known obsidian sources in the Maya region based on their unique chemical elements. Another aspect of this analysis is to determine the accuracy and validity of the Handheld XRF instrument on small and irregular obsidian samples. Furthermore, sourcing analysis allows researchers to acquire information about trade, exchange, and acquisition patterns of the material and gives researchers indications to prehistoric, social, and economic features.

<p>Arsenic (As) is an element that is well known for its toxic capabilities. It is odorless and colorless and is known to contaminate the drinking water of populations in several parts of the world. Routine monitoring of arsenic exposure is usually performed with urine, hair or nail, where samples are collected for laboratory analysis. Arsenic’s strong affinity to keratin rich tissues make skin another possible measurement site, in addition to the latter two tissues mentioned above. In some cases, skin samples are extracted for analysis. This is painful and invasive and is not ideal for <em>in vivo</em> monitoring of arsenic. The ability to quantify elemental concentration non-destructively is the major calling card of x-ray fluorescence (XRF). To that end, work was started on development of XRF detection systems for arsenic. The technique has shown promise for other elements and dramatic improvements in As detection capabilities were previously found when going from a radioisotope-based x-ray source to an x-ray tube based approach.</p> <p>This thesis documents the comparison of three x-ray tube based detection systems intended for the measurement of arsenic in skin. Two benchtop systems were used, with a) extended development of the previously assembled system and b) the first use of a separate detection system. Two handheld x-ray analyzers (portable detection systems) were also investigated in stand mode, where they were attached to a purpose-built mounting stand, provided by the manufacturer, during all analysis. Polyester resin phantoms were used to model arsenic in skin and a nylon backing was used to represent as bulk tissue behind skin. During the course of the work, modifications were made to the laboratory setup associated with the benchtop approaches.</p> <p>A benchtop polychromatic Mo anode x-ray tube based x-ray fluorescence (XRF) detection system was the first system used in this work. Through modifications to the existing design of the system, the lowest minimum detection limit (MDL) achievable was found to be (0.611±0.001) ppm normalized to gross scatter, where ppm is ug of arsenic per gram of dry weight (resin). The measurement time was ~1800 seconds real time. The equivalent (skin) and whole body effective doses delivered were (19±3) uSv and (163±47) uSv respectively. The corresponding direct (un-normalized) MDL was (0.499±0.002) ppm, in agreement with that found previously. Modifications to the system allowed a reduction in the localized effective dose delivered, to achieve this MDL, from (0.64±0.03) uSv previously to (0.14±0.04) uSv here.</p> <p>Next, the current work investigated two handheld x-ray analyzers provided by InnovX. A PiN diode detector based Alpha 4000S model unit (W anode x-ray tube) and a Silicon Drift Detector (SDD) based Delta model (Au anode x-ray tube). Both units were operated in benchtop mode: they were mounted in a stand and a phantom was placed on a kapton exit window. The lowest gross-scatter normalized and direct detection limit with the Alpha 4000S unit was (1.649±0.002) ppm and (1.651±0.002) ppm respectively. The equivalent and whole body effective doses delivered were found to be (9.4±2.2) mSv and (94±22) uSv respectively. The localized effective dose was (6.4±1.5) X 10^-3 uSv. By comparison, the Delta unit produced a gross-scatter and direct normalized detection limit of (0.570±0.002) ppm and (0.558±0.002) ppm respectively. The equivalent dose delivered was found to be (19.0±9.0) mSv. The corresponding localized and whole body effective doses delivered were (9.7±4.6) X 10^-3 uSv and (190±90) uSv respectively.</p> <p>The last system used in the current research was a monochromatic Ag anode x-ray tube based XRF setup. A doubly curved crystal (DCC) was used to select the Ag K-alpha line and focused the beam to a spot size of mm² at the focal length. The phantoms were placed at a farther distance where the beam had expanded to a larger area. The lowest Compton scatter normalized detection limit with the Si(Li) detector was found to be (0.696±0.002) ppm. After characterizing its performance in a range of energies, a silicon drift detector was also used on this system. It had the benefit of higher throughput capabilities and superior resolution. The housing of the detector was sufficiently small that it could be placed closer to the phantom surface than the Si(Li) detector. The lowest Compton-scatter normalized detection limit with the SDD was (0.441±0.003) ppm in 1800 seconds real time. The equivalent dose was found to be (11±2) mSv and the localized and whole body effective doses were found to be (3.92±0.87) X 10^-3 uSv and (110±23) uSv respectively. A significantly lower system dead time was observed with the SDD. Finally, Monte Carlo simulations of the system were performed to evaluate the performance of three ratios when their phantom measurement values were compared against simulations of skin. Results were found to be in agreement to withinin vivo concentration of arsenic in skin (ICRP).</p> <p>Finally, EDXRF measurements were performed on bulk cores of skin, <em>ex vivo</em>. While it was not possible to detect arsenic in the samples, due to the samples being collected from members of the public as opposed to an exposed population, a depth profile of numerous skin samples, starting from the surface and running straight down, was obtained for calcium, iron and copper.</p> / Doctor of Philosophy (PhD)

Microelectromechanical systems (MEMS) technology allows the realization of mechanical parts, sensors, actuators and electronics on silicon substrate. An attractive utilization of MEMS is to develop micro instruments for chemical analysis. An example is gas chromatography (GC) which is widely used in food, environmental, pharmaceutical, petroleum/refining, forensic/security, and flavors and fragrances industries. A MEMS-based micro GC (µGC) provides capabilities for quantitative analysis of complex chemical mixtures in the field with very short analysis time and small amounts of consumables. The aim of this research effort is to enhance the sensitivity and selectivity of µGC instruments by implementing chemical amplification method known as preconcentration. A micro preconcentrator (µPC) extracts the target analytes from the sample matrix, concentrates them, and injects them into the separation column for analysis. This work resulted in the development of silicon-glass bonded chips consisting of 7 mm x 7 mm x 0.38 mm multiport cavity with thousands of embedded 3D microstructures (to achieve high surface-to-volume ratio) coated with polymeric thin film adsorbents. Deep reactive ion etching (DRIE) was the enabling technology for the realization of µPCs. Several coating methods, such as inkjet printing of polymers and polymer precipitation from solution have been utilized to coat complex geometrical structures. One major outcome was the development of cobweb adsorbent structure. Moreover, the porous polymeric adsorbent Tenax TA in the film form was characterized, for the first time, for μPC application and shown to have similar properties to that of the granular form. Several μPC designs were experimentally evaluated for their performance in concentrating volatile organic compounds, including cancer biomarkers, Propofol (anesthetic agent), environmental pollutants, and chemical warfare simulants. The possibility of utilizing the μPCs in practical applications such breath analysis was also demonstrated. / Ph. D.

Constructing common ground and the associated convergent conceptual change is critical to cooperative work and learning. Convergent conceptual change is achieved as participants in a conversation update common ground through presentations, repairs, and acceptances of utterances. People employ available techniques that utilize the least collaborative effort for current purposes. Although sharing physical co-presence of interlocutors' facial expressions doesn't make grounding more efficient even in more open-ended and less task-focused dialogues, visual co-presence of the addressee's workspace is essential to work-related tasks, such as information transmission and collaborative problem-solving. However, handheld-mediated collaborative activity makes sharing the workspace challenging, especially when we consider that handhelds possess small screens and permit activities of a distributed nature. In a handheld-mediated classroom, a teacher must be able to check students' work for various reasons (e.g., grading, checking whether they are following directions correctly or paying attention) and at various phases of the activity. Gazing into the small screen of a handheld over someone's shoulder is a tricky task at best. The teacher may misread the information on the screen and thus provide incorrect feedback. Another challenge involves the difficulty inherent in latecomers joining the collaborative activity when each student is involved with his or her individual and small screen. This exclusion from joining on-going activity can reduce the chance of student's vicarious and serendipitous learning. Although such events may occur naturally in the learning environment, they become important concerns when one attempts to focus collaborative activities with handheld devices. I therefore created a new handheld network service called "Look," which is designed to facilitate the acquisition of common ground and allow a latecomer to do meaningful monitoring of ongoing conversation about the workspace. I tested empirically the value of this shared physical/virtual context in the task of creating common ground by examining task performance and conversation quality. / Ph. D.

<p>Advancements in retinal imaging technologies have drastically improved the quality of eye care in the past couple decades. Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) are two examples of critical imaging modalities for the diagnosis of retinal pathologies. However current-generation SLO and OCT systems have limitations in diagnostic capability due to the following factors: the use of bulky tabletop systems, monochromatic imaging, and resolution degradation due to ocular aberrations and diffraction. </p><p>Bulky tabletop SLO and OCT systems are incapable of imaging patients that are supine, under anesthesia, or otherwise unable to maintain the required posture and fixation. Monochromatic SLO and OCT imaging prevents the identification of various color-specific diagnostic markers visible with color fundus photography like those of neovascular age-related macular degeneration. Resolution degradation due to ocular aberrations and diffraction has prevented the imaging of photoreceptors close to the fovea without the use of adaptive optics (AO), which require bulky and expensive components that limit the potential for widespread clinical use. </p><p>In this dissertation, techniques for extending the diagnostic capability of SLO and OCT systems are developed. These techniques include design strategies for miniaturizing and combining SLO and OCT to permit multi-modal, lightweight handheld probes to extend high quality retinal imaging to pediatric eye care. In addition, a method for extending true color retinal imaging to SLO to enable high-contrast, depth-resolved, high-fidelity color fundus imaging is demonstrated using a supercontinuum light source. Finally, the development and combination of SLO with a super-resolution confocal microscopy technique known as optical photon reassignment (OPRA) is demonstrated to enable high-resolution imaging of retinal photoreceptors without the use of adaptive optics.</p> / Dissertation

Approved for public release, distribution is unlimited / This thesis studies the feasibility of developing a closed-loop shipboard sensor calibration system with two main objectives. The first objective was to reduce the number of personnel required to calibrate a shipboard sensor by 50%. The second was to reduce the time required to complete the calibration process by 60%. This was achieved by displaying the sensor data and the calibration standard data on a tablet PC. Wireless technology was used to transmit the data from the sensor and the calibration standard to the tablet PC. The data from the sensor is sent via IEEE 802.11b wireless LAN using DataSocket protocol and the calibration standard is sent via Bluetooth protocol. The technology can be installed and used on current ships in the United States Navy. Four software programs were developed to accomplish these goals. One program runs on the tablet PC and the other three run on the network capable application processor (NCAP). These four programs accomplish the goals stated. / Lieutenant, United States Navy

Master of Science / Department of Geology / Matthew Totten / The Woodford shale is recognized as an abundant source rock across Oklahoma and much of the midcontinent (Lambert, 1990), and up to 8% of the world’s hydrocarbon reserves are estimated to have been sourced by the Woodford and its equivalents (Fritz et al, 1991). The Woodford shale is far more complex than other Devonian black shales found in North America due to the presence of alternating bands of chert-like amorphous silica and silica-rich shale. Analysis of chert and its possible role in gas generation and storage in shales has been largely overlooked. The goal of this study is to determine if chert size, amounts, or polycrystallinity can be indicators of thermal maturity within the Woodford shale. Handheld XRF analysis was conducted on the whole rock samples, and a mudrock specific sodium bisulfate fusion was used to separate the non-clay fraction. SEM was performed on the resulting separates to study and observe changes in chert fabric, grain-size, and amount. No correlations were observed to indicate that chert is an indicator of thermal maturity within the Woodford shale. Increase in chert growth and amount was also not detected within the size fractions as thermal maturity increases. Handheld XRF proved to be a good proxy for quick, onsite analysis of silica concentrations, as well as the amount of organic matter within drill core. This could be beneficial as hydraulic fracking produces best results in areas of higher silica content, and the wells with the highest organic matter have the highest potential for petroleum accumulations.

Dans cette thèse, j'aborde la question de l'interaction gestuelle sur dispositif mobile. Ces dispositifs, à présent communs, se distinguent des ordinateurs conventionnels principalement par leurs périphériques d'interaction avec l'utilisateur (écrans de taille restreinte mais tactiles, capteurs divers tels que les accéléromètres) ainsi que par le contexte dans lequel ils sont utilisés. Le travail que je présente est une exploration du vaste domaine des techniques d'interaction sur ces dispositifs mobiles. Je structure cet espace en me concentrant sur les techniques à base d'accéléromètres pour lesquelles je propose une taxonomie. Son pouvoir descriptif et discriminant est validé par la classification de trente-sept techniques d'interaction de la littérature. La suite de mon travail se penche sur la réalisation de techniques d'interaction gestuelles pour ces dispositifs mobiles. Avec TouchOver, je montre qu'il est possible de tirer parti de manière complémentaire de deux canaux d'entrée (écran tactile et accéléromètres) pour ajouter un état au glissé du doigt, permettant ainsi d'enrichir cette interaction. Enfin, je m'intéresse aux menus sur dispositif mobile et propose une nouvelle forme de menus gestuels. Je présente leur réalisation avec la bibliothèque logicielle GeLATI qui permet leur intégration à une boîte à outils de développement d'interface graphique préexistante. * / In this thesis, we address the question of gesture interaction on mobile device. These devices, now common, differ from conventional computers primarily by the input devices the user interact with (screen size small but tactile, various sensors such as accelerometers) as well as the context in which they are used. The work presented here is an exploration of the vast area of interaction techniques on these mobile devices. First we try to structure this space by focusing on the techniques based on accelerometers for which we propose a taxonomy. Its descriptive and discriminant power is validated by and the classification of thirty-seven interaction techniques in the literature. Second we focus on the achievement of gestural interaction techniques for these mobile devices. With TouchOver, we show that it is possible to take advantage of complementary two-channels input (touch screen and accelerometers) to add a state to the finger-drag, thus enriching the interaction. Finally, we focus on mobile device menus and offer a new form of sign language menus. We discuss their implementation with the GeLATI software library that allows their integration into a pre-existing GUI toolkit.