Magnetic-Visual Sensor Fusion-based Dense 3D Reconstruction and Localization for Endoscopic Capsule Robots

Reliable and real-time 3D reconstruction and localization functionality is a crucial prerequisite for the navigation of actively controlled capsule endoscopic robots as an emerging, minimally invasive diagnostic and therapeutic technology for use in the gastrointestinal (GI) tract. In this study, we propose a fully dense, non-rigidly deformable, strictly real-time, intraoperative map fusion approach for actively controlled endoscopic capsule robot applications which combines magnetic and vision-based localization, with non-rigid deformations based frame-to-model map fusion. The performance of the proposed method is demonstrated using four different ex-vivo porcine stomach models. Across different trajectories of varying speed and complexity, and four different endoscopic cameras, the root mean square surface reconstruction errors 1.58 to 2.17 cm.Comment: submitted to IROS 201

Instrumentation of sampling aircraft for measurement of launch vehicle effluents

An aircraft was selected and instrumented to measure effluents emitted from large solid propellant rockets during launch activities. The considerations involved in aircraft selection, sampling probes, and instrumentation are discussed with respect to obtaining valid airborne measurements. Discussions of the data acquisition system used, the instrument power system, and operational sampling procedures are included. Representative measurements obtained from an actual rocket launch monitoring activity are also presented

Emerging technologies for the non-invasive characterization of physical-mechanical properties of tablets

The density, porosity, breaking force, viscoelastic properties, and the presence or absence of any structural defects or irregularities are important physical-mechanical quality attributes of popular solid dosage forms like tablets. The irregularities associated with these attributes may influence the drug product functionality. Thus, an accurate and efficient characterization of these properties is critical for successful development and manufacturing of a robust tablets. These properties are mainly analyzed and monitored with traditional pharmacopeial and non-pharmacopeial methods. Such methods are associated with several challenges such as lack of spatial resolution, efficiency, or sample-sparing attributes. Recent advances in technology, design, instrumentation, and software have led to the emergence of newer techniques for non-invasive characterization of physical-mechanical properties of tablets. These techniques include near infrared spectroscopy, Raman spectroscopy, X-ray microtomography, nuclear magnetic resonance (NMR) imaging, terahertz pulsed imaging, laser-induced breakdown spectroscopy, and various acoustic- and thermal-based techniques. Such state-of-the-art techniques are currently applied at various stages of development and manufacturing of tablets at industrial scale. Each technique has specific advantages or challenges with respect to operational efficiency and cost, compared to traditional analytical methods. Currently, most of these techniques are used as secondary analytical tools to support the traditional methods in characterizing or monitoring tablet quality attributes. Therefore, further development in the instrumentation and software, and studies on the applications are necessary for their adoption in routine analysis and monitoring of tablet physical-mechanical properties

Thermal dosimetry for bladder hyperthermia treatment. An overview.

The urinary bladder is a fluid-filled organ. This makes, on the one hand, the internal surface of the bladder wall relatively easy to heat and ensures in most cases a relatively homogeneous temperature distribution; on the other hand the variable volume, organ motion, and moving fluid cause artefacts for most non-invasive thermometry methods, and require additional efforts in planning accurate thermal treatment of bladder cancer. We give an overview of the thermometry methods currently used and investigated for hyperthermia treatments of bladder cancer, and discuss their advantages and disadvantages within the context of the specific disease (muscle-invasive or non-muscle-invasive bladder cancer) and the heating technique used. The role of treatment simulation to determine the thermal dose delivered is also discussed. Generally speaking, invasive measurement methods are more accurate than non-invasive methods, but provide more limited spatial information; therefore, a combination of both is desirable, preferably supplemented by simulations. Current efforts at research and clinical centres continue to improve non-invasive thermometry methods and the reliability of treatment planning and control software. Due to the challenges in measuring temperature across the non-stationary bladder wall and surrounding tissues, more research is needed to increase our knowledge about the penetration depth and typical heating pattern of the various hyperthermia devices, in order to further improve treatments. The ability to better determine the delivered thermal dose will enable clinicians to investigate the optimal treatment parameters, and consequentially, to give better controlled, thus even more reliable and effective, thermal treatments

Investigations on corrosion monitor reliability, calibration, and coverage

Thickness loss due to internal corrosion and erosion is a critical issue in ferromagnetic steel structures that can cause catastrophic failures. Ultrasonic thickness gauges are widely used for the detection of wall thickness. Recently permanently installed ultrasonic sensors have become popular for the inspection of areas suspected to undergo wall thickness loss. However, these are limited by the high cost and requirement of coupling agents. To address these problems, a novel cost-effective, and smart corrosion monitor based on the magnetic eddy current technique is developed in this research. The performance and reliability of the monitor to track internal wall thickness loss is tested successfully through accelerated and real-life aging corrosion tests. Due to the handling and safety issues associated with the powerful magnets in magnetic techniques, a particle swarm-based optimisation method is proposed and validated through two test cases. The results indicate that the area of the magnetic excitation circuit could be reduced by 38% without compromising the sensitivity. The reliability of the corrosion monitor is improved by utilising the active redundancy approach to identify and isolate faults in sensors. A real-life aging test is conducted for eight months in an ambient environment through an accelerated corrosion setup. The results obtained from the two corrosion monitors confirm that the proposed corrosion monitor is reliable for tracking the thickness loss. The corrosion monitor is found to be stable against environmental variations. A new in-situ calibration method based on zero-crossing frequency feature is introduced to evaluate the in-situ relative permeability. The thickness of the test specimen could be estimated with an accuracy of ± 0.6 mm. The series of studies conducted in the project reveal that the magnetic corrosion monitor has the capability to detect and quantify uniform wall thickness loss reliably

Development of Novel Analytical Methods with the Aim of Forensic Analyte Detection using Ultra-Thin Layer Chromatography, Surface Enhanced Raman Spectroscopy, and Magneto-Elastic Wire Sensing

The purpose of this dissertation is to develop analytical methods that aid in the detection of forensic analytes. Forensic analytes require methods with increased sensitivity and low limit of detection capabilities. Improvements in separation techniques, surface enhanced Raman spectroscopic techniques, and wire-less gas sensing can each assist in the detection of trace evidence. When surface enhanced Raman is coupled with thin-layer chromatography a mixture of compounds can be separated and transferred to a metal substrate to be detected using Raman spectroscopy. Surface enhanced Raman scattering enhances the Raman signal intensity by placing a metal substrate in close proximity to an analyte. The new method gives a chemically specific intensified signal along with a chromatographic separation. A traditional separation is performed on a TLC plate, allowed to dry, wetted with a solvent, placed in contact with a metal substrate, and detected using Raman. More efficient chromatographic platforms can be implemented with this method. New efficient chromatographic platforms are also beneficial to the detection of forensic analytes. Recently, photolithographically nanofabricated open system pillar arrays have proved to be more efficient separation platforms when compared to traditional TLC. These platforms are a form of ultra-thin layer chromatography. This dissertation describes the effects of manipulation on the inter-pillar gap distances with respect to band dispersion. The studies herein manipulate the pillar arrays in order to optimize the separation platform. The third method developed involved gas sensing of volatile organic compounds. An amorphous ferromagnetic micro-wire was coated with a polymer, where the polymer swelled in response to the gas introduced. When the gas caused the polymer to swell a differential stress response was applied on the micro-wire. The fabricated sensor was tested on simple organic gases but has capabilities to detect low concentrations of low vapor pressure forensic analytes. All three projects were significant advancements in analytical method development. The analytes used were either fluorescent dyes or volatile organic compounds to test feasibility of each method. More efficient chromatographic platforms were fabricated, surface enhanced Raman was coupled to TLC, and a micro-wire gas sensor was calibrated for the studies performed in this dissertation

Process monitoring and visualization solutions for hot-melt extrusion : a review

Objectives: Hot-melt extrusion (HME) is applied as a continuous pharmaceutical manufacturing process for the production of a variety of dosage forms and formulations. To ensure the continuity of this process, the quality of the extrudates must be assessed continuously during manufacturing. The objective of this review is to provide an overview and evaluation of the available process analytical techniques which can be applied in hot-melt extrusion. Key Findings: Pharmaceutical extruders are equipped with traditional (univariate) process monitoring tools, observing barrel and die temperatures, throughput, screw speed, torque, drive amperage, melt pressure and melt temperature. The relevance of several spectroscopic process analytical techniques for monitoring and control of pharmaceutical HME has been explored recently. Nevertheless, many other sensors visualizing HME and measuring diverse critical product and process parameters with potential use in pharmaceutical extrusion are available, and were thoroughly studied in polymer extrusion. The implementation of process analytical tools in HME serves two purposes: (1) improving process understanding by monitoring and visualizing the material behaviour and (2) monitoring and analysing critical product and process parameters for process control, allowing to maintain a desired process state and guaranteeing the quality of the end product. Summary: This review is the first to provide an evaluation of the process analytical tools applied for pharmaceutical HME monitoring and control, and discusses techniques that have been used in polymer extrusion having potential for monitoring and control of pharmaceutical HME

Status of the NASA YF-12 Propulsion Research Program

The YF-12 research program was initiated to establish a technology base for the design of an efficient propulsion system for supersonic cruise aircraft. The major technology areas under investigation in this program are inlet design analysis, propulsion system steady-state performance, propulsion system dynamic performance, inlet and engine control systems, and airframe/propulsion system interactions. The objectives, technical approach, and status of the YF-12 propulsion program are discussed. Also discussed are the results obtained to date by the NASA Ames, Lewis, and Dryden research centers. The expected technical results and proposed future programs are also given. Propulsion system configurations are shown

Portable “lab-on-chip” platform for bovine mastitis diagnosis in raw milk

Tese de Doutoramento em Ciências Veterinárias, Especialidade de Ciências Biológicas e BiomédicasBovine mastitis is an economic burden for farmers mostly because of decreased milk yield, premature culling and cost of veterinary treatments. The identification of mastitis pathogens is of major importance in order for adequate control measures to be taken, to reduce the risk of appearance of chronic infections, and to target antimicrobial therapy. The aim of this study was to develop and validate a sensitive method for magnetic detection of Streptococcus agalactiae, Streptococcus uberis, Staphylococcus aureus and Staphylococcus epidermidis in raw milk samples. Mastitic milk samples were collected aseptically from 81 cows with subclinical mastitis, from 12 Portuguese dairy farms. Ninety one quarter milk samples were selected based on bacteriological results. All samples were submitted to PCR analysis. In parallel, these milk samples were mixed with a solution combining specific antibodies and magnetic nanoparticles, to be analyzed using a lab-on-a-chip magnetoresistive cytometer, with microfluidics sample handling. This immunological recognition was able to detect bacterial presence above 100 cfu/ ml, depending on antibody and targeted bacteria. Comparison with PCR results showed sensitivities of 73% and 41%, specificity values of 25% and 57%, and PPV values of 35% and 54% for magnetic identification of streptococci species with an anti-S. agalactiae antibody and an anti-GB Streptococcus antibody, respectively. Regarding staphylococci species, the sensitivity values found were of 57.1% and 79.3%, specificities of 75% and 50%, and PPV values of 40% and 95.8% for magnetic identification with an anti-S. aureus antibody and an anti-Staphylococcus spp. antibody, respectively. Both bacterial genus studies translated a fair expectation for a “cow-side” use application, making this integrated platform of potential use after further improvements for fast bacteriological infection screening. Some constraints are described as well as the method´s limitations in bacterial quantification.RESUMO - Plataforma portátil “lab-on-chip” para diagnosticar mastite bovina em leite crú - A mastite bovina representa um custo económico relevante para os produtores de leite principalmente devido ao decréscimo da produção leiteira, abate prematuro e custos associados ao tratamento veterinário. Consequentemente, a identificação atempada dos agentes etiológicos é crítica para a implementação de medidas de controlo adequadas, redução do risco de infecções crónicas e aplicação de uma terapia microbiana específica. O objectivo deste estudo foi desenvolver e validar um método de detecção magnética capaz de identificar Streptococcus agalactiae, Streptococcus uberis, Staphylococcus aureus e Staphylococcus epidermidis em amostras de leite crú. As amostras de leite mastítico utilizadas foram recolhidas de 81 animais com mastite subclínica, de 12 explorações leiteiras nacionais. As amostras de leite de 91 quartos de úbere foram selecionadas tendo em conta os resultados bacteriológicos. Todas as amostras foram analisadas por PCR e pelo citómetro magnetoresistivo “lab-on-chip”, tendo sido necessário neste caso, adicionar uma solução com partículas magnéticas funcionalizadas com anticorpos específicos. Este reconhecimento imunológico detectou presença bacteriana acima das 100 ufc/ml, dependendo do anticorpo e da bactéria-alvo. Comparando com os resultados da análise por PCR, este método de detecção magnética apresentou sensibilidades de 73% e 41%, valores de especificidade de 25% e 57%, e valores VPP de 35% e 54% para identificar espécies de Streptococcus com os anticorpos anti-S. agalactiae e anti-GB Streptococcus, respectivamente. No que diz respeito às espécies de Staphylococcus, os valores de sensibilidade encontrados foram de 57.1% e 79.3%, de 75% e 50% para a especificidade, e de 40% e 95.8% para VPP com os anticorpos anti-S. aureus e anti-Staphylococcus spp., respectivamente. Os dois estudos apontam para uma potencial utilização do tipo “cow-side”, tornando a plataforma integrada potencialmente utilizável para uma rápida monitorização de infecção bacteriológica, após melhorias futuras. O método desenvolvido apresenta algumas restrições e limitações relativamente à quantificação bacteriana