Supercritical Water Oxidation: Testing Of Aqueous Wastewater Solutions For Space Applications

Future extended-duration space missions will only be practicable with effective life support systems that incorporate resource reclamation technologies from bio[1]waste streams. In the case of water reclamation during these missions, Supercritical Water Oxidation (SCWO) has been proposed as an attractive technology. In SCWO processes, organic waste compounds are oxidized in water above its critical point at 374°C and 22 MPa. This work focuses on the SCWO of ersatz wastewater (EWW) streams that simulate waste streams typically observed during International Space Station (ISS) isolated crew missions. A tubular reactor was designed and built at NASA’s Glenn Research Center (NASA-GRC) to allow the oxidation of a continuous flow of ersatz waste at isobaric supercritical conditions. A description of the reactor design and the operational procedures for the heat-up, injection, and establishment of steady-state conditions are presented. The oxidizer in these tests, air (21% O2 with balanced N2) was used and “fuel” (i.e., EWW at different levels of dilution) were independently heated and pressurized as they entered the reactor in a co-flow configuration at supercritical conditions. Experiments were performed at reactor set point temperatures and pressures ranging from 550-610°C and 26-28 MPawith air flows ranging from 0.75 to 2.5 standard liters per minute (SLPM) and fuel flows ranging from 2.0 to 4.0 mL/min. Qualitative assessments of the extent of conversion (odor, foaming, turbidity) are discussed along with quantitative measurements using Raman spectroscopy and Total Organic Carbon (TOC) analysis. Additional co-fuel experiments using ethanol were conducted to increase internal bulk temperatures for conversion of the dilute EWW stream. The overall results of the EWW tests concluded that with appropriate reaction temperatures, equivalence ratios favoring excess air, and residence time of 55 seconds to 93 seconds, near 100% TOC conversion could be achieved. An additional preliminary study for less complex mixtures using urea-aqueous solutions was conducted. Preliminary results show a similar trend in the EWW results, but with challenges in maintaining sufficient bulk fluid temperatures due to reactor constraints, thus limiting complete conversion of ammonia. Preliminary on-time gas measurements taken presents great potential for future gas analysis from detections of CO2 and NO

The Effect of Moderate Parkinson's Disease on the Biomechanics of Compensatory Backwards Stepping

Postural instability leading to falls is one of the major unmet needs in the treatment of Parkinson's disease (PD). The progression of postural instability is not well understood, and a better understanding of the biomechanics underlying the progression of postural instability may be instrumental in the development of more sensitive clinical measures of postural instability and fall risk in PD. The biomechanical analysis of the response to a balance perturbation provides an opportunity to better understand postural instability in PD. This study examined the compensatory stepping response to a backwards pull in participants with moderate PD compared to age-range matched healthy controls. The first study investigated the overall response to a balance disturbance in moderate PD, and found that patients with moderate PD utilized more steps to regain balance, had a longer weight shift time, and used a base-width neutral step as a strategy to regain balance, compared to controls. The second study further investigated the compensatory response by focusing on the preparation phase and found that participants with moderate PD used multiple anticipatory postural adjustments (APAs), resulting in longer liftoff times and significantly different movement in the center of pressure prior to liftoff compared to healthy controls. The third study investigated the effects of PD and step strategy (single step, multiple steps, and a base-width neutral step) on balance recovery and found that participants with moderate PD took significantly longer to recover balance, and that the type of strategy used to respond to the disturbance significantly impacted recovery time. Additionally, the use of a base-width neutral step as the first step in the response emerged as a strategy that has not been previously documented and significantly delays balance recovery. These results suggest that moderate PD significantly impairs the compensatory response to a backwards pull. Furthermore, this impairment could be attributed to a delay in the preparation phase of the step response. This delay was associated with the use of multiple anticipatory postural adjustments and/or the use of a base-width neutral step as the first step in the response. Further study should examine the progression of impairment in these compensatory responses across PD severity levels, and the correlation with fall risk

Compound Control of Electromagnetic Linear Actuator Based on Fuzzy Switching

Due to the motion control system of electromagnetic linear actuator (EMLA) is a nonlinear system with poor controllability, single control strategy has been difficult to meet the requirements of its control. A compound control strategy based on inverse system control (ISC) and proportional-integral (PI) is designed in this paper. Switching between two algorithms, which is based on the fuzzy rules, prevents the control algorithm to jitter and jump. System model is build under Matlab/Simulink to do simulation analysis. The designed controller is integrated into the system simulation model and the system software of digital signal processor (DSP) controller. Simulation and test results show that the compound control strategy using fuzzy switching rules achieves the smooth transition of two control algorithms, and the goal of any position location, and continuous adjustment in 0~4mm lift. Positioning accuracy is up to ± 0.02mm, while the response time is less than 10ms

Abnormal Neuromuscular Fatigue and Motor Performance of the Knee Extensors Post Stroke

Stroke causes paresis in leg muscles, such as the knee extensors, that significantly impairs motor control and function during tasks such as walking. Reduced endurance and increased kinematic asymmetries during walking over time indicate paretic musculature may fatigue more quickly than non-paretic musculature. The primary purpose of this study was to identify abnormalities in neuromuscular fatigue (reduction in force over time) of the paretic knee extensors and associate them with motor performance. We investigated the effects of repeated six second isometric submaximal (30% of maximum voluntary contraction) knee extensor fatiguing contractions on task failure and motor performance in ten chronic stroke subjects and compared them to ten, healthy controls. A systematic criterion determined task failure. We recorded knee extensor torque, stretch reflex responses, surface electromyography (EMG) of agonist (rectus femoris and vastus medialis) and antagonist (medial hamstring) knee extensor muscles, and muscle fiber conduction velocity (CV) of the vastus lateralis muscle as interpretive measures of neuromuscular fatigue. A power spectral density analysis of the intermittent target torque estimated the effect of fatigue on force fluctuations. Two isometric submaximal torque tracking tasks performed before and after fatigue provided direct measures of fatigue on force variability and error. Stroke subjects failed the fatiguing task significantly sooner than control subjects. In controls, averaged rectified EMG amplitude significantly increased and CV significantly reduced with fatigue, while no changes occurred in stroke. Fatigue caused a spectral shift toward higher force fluctuation frequencies in control but not stroke subjects. Time to task failure in stroke subjects negatively correlated with their walking speed. Additionally, pre-fatigue torque variability and error was greater in stroke than control subjects, and increased significantly with fatigue. In summary, paretic knee extensors have increased neuromuscular fatigability of the paretic knee extensors which relates to walking speed. The interpretative measures suggest that central factors may contribute more to time-to-task failure as compared to peripheral (muscular factors) in stroke survivors. Performance data demonstrate pre and post-fatigue impairments in sub-maximal force regulation. Taken together, these data demonstrate previously un-described impairments in paretic knee extensor force generation and regulation that could contribute to motor dysfunction post stroke

DESIGN OF A CUSTOM SOFTWARE APPLICATION TO MONITOR AND COMMUNICATE CNC MACHINING PROCESS INFORMATION TO AID IN CHATTER IDENTIFICATION

In any manufacturing environment, it is important to be able to monitor the Computer Numerical Control (CNC) machining process so that high quality parts can be produced in the least amount of time in order to be profitable. This involves acquiring the proper parameters needed from the machine\u27s controller, which can prove to be difficult with proprietary machine tools that tend to limit access to the internal data collected by the controller. This closed approach to controller design also means that many technological advances that have recently become prevalent in society are not being adopted in the manufacturing industry, preventing the interoperability between hardware and software components and adding to the shortcomings in communicating the necessary machining parameters to machine operators. The project described in this thesis offers a solution to some of the communication, productivity, and part quality problems in the American manufacturing industry by providing a custom software application that integrates MTConnect, an emerging interoperable data communication standard, with proprietary data acquisition tools and custom sensors to monitor and communicate CNC machining process information. The application described in this thesis was designed to aid in the identification of chatter conditions to the machine operator and to other users to take action for chatter suppression and avoidance. Chatter is an undesirable phenomenon that can reduce part quality and increase tool wear. These consequences result in higher costs to replace damaged parts and tools as well as increasing the amount of machine downtime which can reduce a company\u27s overall productivity. Once chatter is detected in the audible frequency range, damage to the workpiece has already occurred. Therefore, an early identification and communication method with the machine tool is warranted to easily monitor the machine in the event of impending dynamic part damage. This application was developed to provide a means to monitor cutting conditions to reduce and prevent chatter in the machining process and to aid in analysis to avoid subsequent unstable operating conditions. Preserving part quality and productivity in manufacturing is also dependent on accurate information provided about the specific parts involved in the machining process. In addition to monitoring the process, this application facilitates the communication of part-specific information by improving the input and tracking of part numbers, and organizes the machining process information in a central location according to the specific part. Improving the part tracking process can aid in the organization of data to analyze the machining process for increased quality in future operations. The application can also be customized for other implementations, which can benefit many different industrial manufacturing facilities as well as academics in performing experimental research. It is important for the manufacturing industry and its partners in academia to be able to bridge the communication gap to increase the knowledge of the machining process and therefore manufacturing productivity and profitability

Advanced photonic crystal enhanced microscopy

This study seeks to expand the field of photonic crystal enhanced microscopy by extending simple proof-of-concept experiments to advanced biological applications. There are four distinct projects that are related to a central theme: sophisticated microscope instrumentation for photonic crystal biosensing. Also included in this study is a comprehensive list of software that I have written in order to control and optimize various instruments and data processing, including the band diagram transmission set-up, enhanced fluorescence label-free microscope and objective coupled label-free microscope. In the initial project, I demonstrate the first hybrid total internal reflection and photonic crystal microscope. This imaging system benefits from the low background signal of total internal reflection in addition to the enhanced fluorescence effect of photonic crystals at resonance. The noise of this system is shown to be dominated by the TiO$_2$ layer autofluorescence which increases exponentially with increasing illumination intensity because of the enhanced electric field in the TiO$_2$ layer. The response of the fluorophores with increasing laser power is measured, and a linear fluorescence response within 30\%-90\% of the maximum laser output power is observed, implying that the emission signal of the fluorophores could be intensified further by the photonic crystal enhanced fluorescence phenomena. Data acquired outside of this range did not create a statistically significant set of measurements as shown in the histograms, standard deviations and number of acquired traces. The second project is an angle-scanning technique that I developed that can be used with photonic crystal sensors in order to create 3D tomographic fluorescence and label-free images. Using photonic crystal enhanced fluorescence, this method measures the distance a fluorophore resides from the surface. For photonic crystal-based label-free biosensing, it constructs 3D refractive index maps. Simulations using rigorous coupled waveguide analysis reinforce the validity of the concept, and they are used as a visual aid when describing the decay of the evanescent field profile with angle. A microarray of fluorescent spots is used to demonstrate how to acquire and process the data for the technique. The procedure is applied to the processed spot array, which shows an unexpected nonlinear trend. The small molecule binding assumption that is used in one of the steps is validated with numerical simulations as well. The next project is the process I have developed to maximize the label-free sensitivity of transparent photonic crystal devices. The spectroscopic instrument that I built to acquire full band diagrams automatically is described, and included in this section is the software that handles the data acquisition and post-processing analysis. The band diagrams and corresponding wavelengths of minimum transmission for an ERv1 device in air, water and isopropyl alcohol are recorded and the label-free sensitivity, also known as the change in resonance wavelength per bulk refractive index unit, is plotted against angle. This analysis demonstrates that the highest sensitivities for both transverse electric and transverse magnetic polarizations occur at normal incidence. This trend is reinforced further with computational software simulations. The band diagram work expands to the angle of minimum transmission curves, which typically are employed when using high-resolution microscopes. The study indicates that the optimal placement of the source center wavelength is slightly red-shifted from the point of inflection of the band diagram and that a narrow band source yields slightly higher angle sensitivity. These results are used to direct the design of photonic crystal enhanced instruments. In the final phase of this study, I record the improvements that I have made to the current photonic crystal enhanced microscope, which is also known as the enhanced fluorescence and label-free microscope. These include the modifications of the optical design, software interface, data acquisition and post-acquisition data processing routines. Also, I characterize and address the current limitations of the system, such as spatial resolution, limit of detection, source of noise and image defects. Label-free images that are acquired with the current angle-scanning tool are shown. The protocol for the enhanced fluorescence and label-free microscope contributed to the design of the new objective coupled label-free microscope, which I have built specifically for the application of high-resolution label-free cell imaging

BIOMECHANICAL MARKERS AS INDICATORS OF POSTURAL INSTABILITY PROGRESSION IN PARKINSON'S DISEASE

The long term objective of this research is to identify quantitative biomechanical parameters of postural instability in patients with Parkinson’s disease (PD) that can in turn be used to assess fall risk. Currently, clinical assessments in PD are not sufficiently sensitive to predict fall risk, making a history of falls to be the best predictor of a future fall. Identifying biomechanical measures to predict risk of falls in PD would provide a quantitative justification to implement fall-reducing therapies prior to a first fall and help prevent the associated debilitating fractures or even morbidity. While past biomechanical studies have shown the presence of balance deficits in PD patients, which often include a broad spectrum of disease stages, compared to healthy controls (HC), no studies have assessed whether such parameters can distinguish the onset of postural instability prior to clinical presentation, and if such parameters persist following clinical presentation of postural instability. Toward this end this study had three goals: • Determine if biomechanical assessment of a quasi-static task, postural sway, could provide preclinical indication of postural instability in PD. • Define a mathematical model (based on principal component analysis, PCA) with biomechanical and clinical measures as inputs to quantitatively score earlier postural instability presence and progression in PD. • Investigate if biomechanical assessment of a dynamic task, gait initiation, could provide preclinical indication of postural instability in PD. Specific Aim 1 determined that some biomechanical postural sway variables showed evidence of preclinical postural instability and increased with PD progression. This aim distinguished mild PD (Hoehn and Yahr stage (H&Y) 2, without postural deficits) compared to HC suggesting preclinical indication of postural instability, and confirmed these parameters persisted in moderate PD (H&Y 3, with postural deficits). Specifically, trajectory, variation, and peak measures of the center of pressure (COP) during postural sway showed significant differences (p < .05) in mild PD compared to healthy controls, and these differences persisted in moderate PD. Schwab and England clinical score best correlated with the COP biomechanical measures. These results suggest that postural sway COP measures may provide preclinical indication of balance deficits in PD and increase with clinical PD progression. Specific Aim 2 defined a PCA model based on biomechanical measures of postural sway and clinical measures in mild PD, moderate PD, and HC. PCA modeling based on a correlation matrix structure identified both biomechanical and clinical measures as the primary drivers of variation in the data set. Further, a PCA model based on these selected parameters was able to significantly differentiate (p < .05) all 3 groups, suggesting PCA scores may help with preclinical indication of postural instability (mild PD versus HC) and could be sensitive to clinical disease progression (mild PD versus moderate PD and moderate PD versus HC). AP sway path length and a velocity parameter were the 2 primary measures that explained the variability in the data set, suggesting further investigation of these parameters and mathematical models for scoring postural instability progression is warranted. Specific Aim 3 determined that a velocity measure from biomechanical assessment of gait initiation (peak COP velocity towards the swing foot during locomotion) showed evidence of preclinical postural instability in PD. Because balance is a complex task, having a better understanding of both quasi-static (postural sway) and dynamic (gait initiation) tasks can provide further insight about balance deficits resulting from PD. Several temporal and kinematic parameters changed with increasing disease progression, with significant difference in moderate PD versus HC, but missed significance in mild PD compared to HC. Total Unified Parkinson’s Disease Rating Scale (UPDRS) and Pull Test clinical scores best correlated with the biomechanical measures of the gait initiation response. These results suggest dynamic biomechanical assessment may provide additional information in quantifying preclinical postural instability and progression in PD. In summary, reducing fall risk in PD is a high priority effort to maintain quality of life by allowing continued independence and safe mobility. Since no effective screening method exists to measure fall risk, our team is developing a multi-factorial method to detect postural instability through clinical balance assessment, and in doing so, provide the justification for implementing fall reducing therapies before potentially debilitating falls begin

Optická kontrola průmyslového výrobku

The implementation of algorithms based on computer vision to the industry has brought great advantages when carrying out inspections of industrial products, that is why this document focuses on the realization of a 3D inspection of an object through the method of Photometric Stereo. A method that is based on taking images under different lighting directions, thus allowing estimating the map of the surface of the object under inspection. To develop this method, a light ring from the Smart Light company with its respective controller and a Basler monochrome camera was implemented. During the development of this master's thesis, it was possible to observe the operation of each of the stages to carry out the inspection, in this case, the capture of images, the reconstruction method, and the calibration process to convert pixels to real units and thus to be able to compare the dimensions obtained by the algorithm concerning the real measurements of the object. Finally, the response of the system to objects that differ from one another concerning geometry, size, or material is analyzed and thus the precision of the approach used is verified.Implementace algoritmů založených na počítačovém vidění v průmyslu přinesla velké výhody při provádění inspekcí průmyslových produktů, proto se tento dokument zaměřuje na realizaci 3D inspekce objektu metodou fotometrického sterea. Metoda, která je založena na pořizování snímků v různých směrech osvětlení, což umožňuje odhadnout mapu povrchu kontrolovaného objektu. K vývoji této metody byl využit segmentový prstencový osvětlovač od společnosti Smart Light s příslušným ovladačem a monochromatickou kamerou Basler. Během vývoje této diplomové práce je možné sledovat provoz každé z fází provádění kontroly, v tomto případě pořizování snímků, metodu rekonstrukce a proces kalibrace pro převod pixelů na skutečné jednotky, a tak být schopen porovnat rozměry získané algoritmem týkajícím se skutečných měření objektu. Nakonec je analyzována odezva systému na objekty, které se navzájem liší, pokud jde o geometrii, velikost nebo materiál, a ověřuje se tak přesnost použitého přístupu.450 - Katedra kybernetiky a biomedicínského inženýrstvívýborn

High-resolution continuous-flow analysis setup for water isotopic measurement from ice cores using laser spectroscopy

Here we present an experimental setup for water stable isotope (&delta;¹⁸O and δD) continuous-flow measurements and provide metrics defining the performance of the setup during a major ice core measurement campaign (Roosevelt Island Climate Evolution; RICE). We also use the metrics to compare alternate systems. Our setup is the first continuous-flow laser spectroscopy system that is using off-axis integrated cavity output spectroscopy (OA-ICOS; analyzer manufactured by Los Gatos Research, LGR) in combination with an evaporation unit to continuously analyze water samples from an ice core. <br><br> A Water Vapor Isotope Standard Source (WVISS) calibration unit, manufactured by LGR, was modified to (1) enable measurements on several water standards, (2) increase the temporal resolution by reducing the response time and (3) reduce the influence from memory effects. While this setup was designed for the continuous-flow analysis (CFA) of ice cores, it can also continuously analyze other liquid or vapor sources. <br><br> The custom setups provide a shorter response time (~ 54 and 18 s for 2013 and 2014 setup, respectively) compared to the original WVISS unit (~ 62 s), which is an improvement in measurement resolution. Another improvement compared to the original WVISS is that the custom setups have a reduced memory effect. <br><br> Stability tests comparing the custom and WVISS setups were performed and Allan deviations (&sigma;_Allan) were calculated to determine precision at different averaging times. For the custom 2013 setup the precision after integration times of 10³ s is 0.060 and 0.070 &permil; for δ¹⁸O and δD, respectively. The corresponding &sigma;_Allan values for the custom 2014 setup are 0.030, 0.060 and 0.043 &permil; for &delta;¹⁸O, δD and &delta;¹⁷O, respectively. For the WVISS setup the precision is 0.035, 0.070 and 0.042 &permil; after 10³ s for δ¹⁸O, δD and &delta;¹⁷O, respectively. Both the custom setups and WVISS setup are influenced by instrumental drift with δ¹⁸O being more drift sensitive than δD. The &sigma;_Allan values for δ¹⁸O are 0.30 and 0.18 &permil; for the custom 2013 and WVISS setup, respectively, after averaging times of 10⁴ s (2.78 h). Using response time tests and stability tests, we show that the custom setups are more responsive (shorter response time), whereas the University of Copenhagen (UC) setup is more stable. More broadly, comparisons of different setups address the challenge of integrating vaporizer/spectrometer isotope measurement systems into a CFA campaign with many other analytical instruments