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Research on enhancing the utilization of digital multispectral data and geographic information systems in global habitability studies

The University of Kansas Applied Remote Sensing (KARS) program is engaged in a continuing long term research and development effort designed to reveal and facilitate new applications of remote sensing technology for decision makers in governmental agencies and private firms. Some objectives of the program follows. The development of new modes of analyzing multispectral scanner, aerial camera, thermal scanner, and radar data, singly or in concert in order to more effectively use these systems. Merge data derived from remote sensing with data derived from conventional sources in geographic information systems to facilitate better environmental planning. Stimulation of the application of the products of remote sensing systems to problems of resource management and environmental quality now being addressed in NASA's Global Habitability directive. The application of remote sensing techniques and analysis and geographic information systems technology to the solution of significant concerns of state and local officials and private industry. The guidance, assistance and stimulation of faculty, staff and students in the utilization of information from the Earth Resources Satellite (LANDSAT) and Aircraft Programs of NASA in research, education, and public service activities carried at the University of Kansas.

Martinko, E. A.↗

Recent Advances in Thermoplastic Puncture-Healing Polymers

Self-healing materials provide a route for enhanced damage tolerance in materials for aerospace applications. In particular, puncture-healing upon impact has the potential to mitigate significant damage caused by high velocity micrometeoroid impacts. This type of material also has the potential to improve damage tolerance in load bearing structures to enhance vehicle health and aircraft durability. The materials being studied are those capable of instantaneous puncture healing, providing a mechanism for mechanical property retention in lightweight structures. These systems have demonstrated healing capability following penetration of fast moving projectiles -- velocities that range from 9 mm bullets shot from a gun (approx.330 m/sec) to close to micrometeoroid debris velocities of 4800 m/sec. In this presentation, we report on a suite of polymeric materials possessing this characteristic. Figure 1 illustrates the puncture healing concept. Puncture healing in these materials is dependent upon how the combination of a polymer's viscoelastic properties responds to the energy input resulting from the puncture event. Projectile penetration increases the temperature in the vicinity of the impact. Self-healing behavior occurs following puncture, whereby energy must be transferred to the material during impact both elastically and inelastically, thus establishing two requirements for puncture healing to occur: a.) The need for the puncture event to produce a local melt state in the polymer material and b.) The molten material has to have sufficient melt elasticity to snap back and close the hole. 1,2 Previous ballistic testing studies revealed that Surlyn materials warmed up to a temperature approx.98 C during projectile puncture (3 C higher than it s melting temperature). 1,2 The temperature increase produces a localized flow state and the melt elasticity to snap back thus sealing the hole. Table 1 lists the commercially polymers studied here, together with their physical properties. The polymers were selected based on chemical structure, tensile strengths, tensile moduli, glass transition temperature, melting temperatures, and impact strength. The thermal properties of the polymers were characterized by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Mechanical properties were assessed by a Sintech 2W instron according to ASTM D1708 or D638 at crosshead speeds of 5.08 cm/min. 7.6 cm x 7.6 cm panels of the different materials were prepared and ballistic testing was performed at various temperatures. The panels were shot with a .223 caliber semiautomatic rifle from a distance of 23 meters at various temperatures. Chronographs were used to measure initial and final bullet velocity. Temperatures at the site of impact were measured using a FLIR ThermaCAM S60 thermal camera. A Vision Research model Phantom 9 high speed video camera was used to capture high speed video footage of ballistics testing.

Gordon, K. L.↗

Design and Preliminary Testing of the International Docking Adapter's Peripheral Docking Target

The International Docking Adapter's Peripheral Docking Target (PDT) was designed to allow a docking spacecraft to judge its alignment relative to the docking system. The PDT was designed to be compatible with relative sensors using visible cameras, thermal imagers, or Light Detection and Ranging (LIDAR) technologies. The conceptual design team tested prototype designs and materials to determine the contrast requirements for the features. This paper will discuss the design of the PDT, the methodology and results of the tests, and the conclusions pertaining to PDT design that were drawn from testing.

Foster, Christopher W.↗

Advanced in In Situ Inspection of Automated Fiber Placement Systems

Automated Fiber Placement (AFP) systems have been developed to help take advantage of the tailorability of composite structures in aerospace applications. AFP systems allow the repeatable placement of uncured, spool fed, preimpregnated carbon fiber tape (tows) onto substrates in desired thicknesses and orientations. This automated process can incur defects, such as overlapping tow lines, which can severely undermine the structural integrity of the part. Current defect detection and abatement methods are very labor intensive, and still mostly rely on human manual inspection. Proposed is a thermographic in situ inspection technique which monitors tow placement with an on board thermal camera using the preheated substrate as a through transmission heat source. An investigation of the concept is conducted, and preliminary laboratory results are presented. Also included will be a brief overview of other emerging technologies that tackle the same issue. Keywords: Automated Fiber Placement, Manufacturing defects, Thermography

Juarez, Peter D.↗

Transition measurements of upper and lower rotor blade surfaces in forward flight with thermography

Thermography allows for imaging the location of laminar-to-turbulent boundary layer transition on surfaces in air flows. The determination of BL transition of rotor blades was done in 2017 on the lower surface of a rotor blade in forward flight in the NASA Langley 14- by 22-Foot Subsonic Tunnel Subsonic Wind Tunnel. This article reports on the follow-on experiment in the same facility and the same blades where thermography was performed on both upper and lower surface synchronously, with the upper surface mapped throughout the full azimuthal range. Blade-tracking rotating mirrors were used for each thermal camera and were synchronized for simultaneous image acquisition. Furthermore, the Differential Infrared Thermography (DIT) technique depicts the unsteady nature of the BL transition in forward flight. Results are presented and discussed. These data are the first ever recorded of both surfaces of a rotor in forward flight.

Boundary layer transition↗

Light-concentrating microcone array for improving performance of infrared imaging devices

Light-harvesting low-index (n=1.6) microconical arrays are proposed for increasing the sensitivity and the signal-to-noise ratio (SNR) of mid-wave infrared (MWIR) focal plane arrays (FPAs) used in thermal cameras. Numerical modeling showed a 3-D Power enhancement factor ~ 50 in MWIR for 10° tapered microcones with Dt/Db = 60 μm/8μm and h=150μm, where Dt and Db are the top and bottom diameters of microcones, respectively. Such microconical arrays were fabricated in photoresist by using a nanoscribe tool directly on top of the front-illuminated Ni/Si Schottky-barrier, and three-fold enhancement in the photocurrent response was observed. The proposed approach permits increase of the SNR and the operation temperature of the MWIR imaging devices.

Astratov, Vasily N.↗

Laser Beam Welding Benchmark Experiments Performed in Reduced Gravity and Vacuum

Laser beam welding (LBW) is affected by the extreme temperatures, reduced pressure, and reduced gravity present in space environments. Gravity and pressure especially influence its melt pool and solidification dynamics. A compact, modular vacuum chamber adaptable to flight platforms from parabolic to orbital currently hosts an experiment to investigate the combined influence of reduced gravity and pressure on LBW. A swappable cartridge contains a rotating platen on which customizable workpieces can be welded under vacuum, greatly increasing experimental throughput. Instrumentation includes weld and thermal cameras observing the process, thermocouples placed on workpieces, accelerometers, and vacuum sensors. Experimental data gathered during the welding process will be combined with post-flight nondestructive evaluation, metallography, and mechanical testing to provide validation datasets for computational modeling. Phase I of this effort involves a parabolic flight campaign in low gravity while an anticipated Phase II would proceed to in-space demonstration to access extended duration microgravity.

in-space welding↗

Utilization of Unmanned Aircraft Systems for Environmental Purposes at the Savannah River Site – 26578

Born in the 1950s, the Savannah River Plant was constructed as a plutonium and tritium production plant. As the Cold War era came and went, a change of direction was signaled when the name of the facility changed from Savannah River Plant to Savannah River Site (1989) – the main mission at Savannah River shifted from “production” to “cleanup.” The Department of Energy is responsible for managing the 310 square miles of land that is the Savannah River Site and the cleanup/remediation activities that occur. The Savannah River National Laboratory utilizes unmanned aircraft systems to assist with some of those environmental monitoring and remediation activities. One function of unmanned aircraft systems at the Savannah River National Laboratory is conducting aerial photography and videography. Various infrastructure evaluations have been performed with unmanned aircraft – facility rooftop inspections, water tower lock verifications, earthen dam surveys, etc. An unmanned aircraft system has been used for progress footage of remediation projects – Dunbarton Bay remediation, Saltstone Disposal Unit construction, etc. Thermal cameras on an unmanned aircraft system are used to help identify cracks/leaks in structures from vantage points not readily accessible by personnel. Virtual tours of different waste units are conducted with unmanned aircraft systems for Site groups and federal/state regulators to save costs and travel time. Additionally, advanced remote sensing technologies are used on unmanned aircraft systems at the Savannah River Site. Light Detection and Ranging uses laser pulses to measure distances to the Earth's surface or other targets to create highly detailed topographic maps that accurately portray terrain (e.g., elevation changes, slopes, and contours). Data collection with a Light Detection and Ranging unit mounted on an unmanned aircraft system is quick and efficient – large-area surveys are conducted in shorter time frames. Because Light Detection and Ranging can penetrate through foliage and vegetation to ground level, it is being used in conjunction with a watershed model to study the General Separations Area of the Site to determine stormwater flow volume and direction, monitor stream stability, and forecast river flow behavior. A hyperspectral camera captures a wide spectrum of electromagnetic wavelengths across numerous narrow bands, beyond what the human eye can see. It provides detailed spectral information about the objects or surfaces in an image, which can be used to identify and analyze materials based on their spectral signatures. A hyperspectral camera mounted on an unmanned aircraft system has been used at the Savannah River Site for non-destructive evaluation of concrete and concrete structures. Unmanned aircraft systems at the Savannah River Site are also used for the application of herbicide on identified rooftops. P-Reactor and R-Reactor are entombed nuclear reactors at the Savannah River Site. Unwanted vegetation is often present on these rooftops – over time roots can penetrate seams, cracks, and joints of the general roof and concrete caps, leading to water ingress and deterioration of the structural components. For time and cost efficiencies as well as in the interest of personnel safety, an unmanned aircraft is used to dispense herbicide on rooftop areas where vegetation is noticed to help alleviate the issues/hazards.

Lorier, Troy [Savannah River National Laboratory (↗

Novel soft x-ray multi-energy camera to study thermal plasmas on WEST

A multi-energy soft x-ray (SXR) pinhole camera has been built, calibrated and deployed on the WEST tokamak to aid the study of thermal plasmas. This novel imaging diagnostic technique employs a 2D pixelated x-ray detector in which the lower energy threshold for photon detection can be adjusted independently on each pixel. This innovation allows the simultaneous measurement of x-rays with space, time and energy resolution. Measurements at lower energy (2–6 keV) dominated by tungsten line emission are used to estimate the tungsten concentration and the plasma ΔZ eff . Measurements at higher energy (11–18 keV), where only continuum emission is present, are employed to infer the plasma electron temperature. Other applications of this powerful diagnostic include the determination of the plasma SXR centroid vertical position, characterization of tungsten UFOs and various real-time measurements.

electron temperature↗

Pan and Tilt Platform for a Thermal Vacuum Video Camera

The purpose of the Space Simulation Test Engineering (SSTE) Section at NASA Goddard Space Flight Center is "to provide full service test support, engineering expertise, and state-of-the-art facilities to perform simulated space and thermal cycle testing of Earth orbit and deep space flight hardware"(ref. 1). During the Integration & Testing phase of space flight projects, flight hardware must successfully demonstrate its functionality under conditions similar to the actual environment experienced in space. When testing hardware with mechanical components, such as antenna extensions, door openings, or solar panel deployments, visual observation would allow test personnel to verify mechanical operations in real-time. A video camera can supply data that the usual sensors inside a TV chamber cannot provide. Since mechanical functional testing could affect multiple regions of a test item, a camera with a fixed position may not be able to monitor and record the performance of different components of a mechanism, especially for large test items. By mounting the camera to a Pan and Tilt Platform, the camera can cover a larger area and its field-of-view (FOV) will increase significantly. This paper details the design process for the Pan and Tilt Platform.

Lui, Yan↗

Novel imaging technique for thermal neutrons using a fast optical camera

A novel imaging technique for thermal neutrons using a fast optical camera is presented. Thermal neutrons are reacted with 6 Lithium to produce a pair of 2.73 MeV tritium and 2.05 MeV alpha particles, which in turn interact in a thin layer of LYSO crystal scintillator to produce a localized flash of light. These photons are directed by a pair of lenses to a micro-channel plate intensifier, and its output is connected to the optical camera, TPX3CAM. The results from the camera are reconstructed through a custom algorithm. Various cutting parameters were found through data analysis to eliminate the background, and they were shown effective in matching the simulated rate of the neutron source. The system is fast with 40 ns decay time and allows free-space light collection, both vastly enhances flexibility of neutron detection.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Influencing Activity of Bats by Dimly Lighting Wind Turbine Surfaces with Ultraviolet Light

Wind energy producers need deployable devices for wind turbines that prevent bat fatalities. Based on the speculation that bats approach turbines after visually mistaking them for trees, we tested a potential light-based deterrence method. It is likely that the affected bats see ultraviolet (UV) light at low intensities. Here, we present the results of a multi-month experiment to cast dim, flickering UV light across wind turbine surfaces at night. Our objectives were to refine and test a practical system for dimly UV-illuminating turbines while testing whether the experimental UV treatment influenced the activity of bats, birds, and insects. We mounted upward-facing UV light arrays on turbines and used thermal-imaging cameras to quantify the presence and activity of night-flying animals. The results demonstrated that the turbines can be lit to the highest reaches of the blades with “invisible” UV light, and the animal responses to such experimental treatment can be concurrently monitored. The UV treatment did not significantly change nighttime bat, insect, or bird activity at the wind turbine. Our findings show how observing flying animals with thermal cameras at night can help test emerging technologies intended to variably affect their behaviors around wind turbines.

17 WIND ENERGY↗

An in-depth assessment of internal contamination in the Wide Field/Planetary Camera

Following thermal vacuum/thermal balance testing, a gray haze was discovered on the corners of the Hubble Space Telescope Wide-Field/Planetary Camera aperture window. The phenomenon was suggested to be a result of molecular transport from a low-outgassig structural adhesive. Detailed analysis, both chemical and analytical, were conducted to assess the formation of the haze. Each material was considered individually, as it was not known if the actual contamination was a result of one, many, or possibly none of the materials considered. Results of the analytical assessment and the comparison with the chemical analyses provided incontrovertible evidence as to the cause of the window haze. The resultant cleanup and subsequent elimination of the problem are also addressed.

Maag, Carl↗

Lessons Learned from the Wide Field Camera 3 TV1 and TV2 Thermal Vacuum Test Campaigns

The Wide Field Camera 3 (WFC3) instrument has undergone two complete thermal vacuum tests (TV1 and TV2), during which valuable lessons were learned regarding test configuration, test execution, model capabilities, and modeling practices. The very complex thermal design of WFC3 produced a number of challenging aspects to ground testing with numerous ThermoElectric Coolers and heat pipes, not all of which were functional. Lessons learned during TV1 resulted in significant upgrades to the model capabilities and a change in the test environment approach for TV2. These upgrades proved invaluable during TV2 when pretest modeling assumptions proved to be false. Each of the lessons learned relate to one of two following broad statements: 1. Ensure the design can be tested and that the effect of non-flight like conditions is well understood, particularly with respect to non passive devices (TECs, Heat Pipes, etc) 2. Ensure that the model is sufficiently detailed and is capable of predicting off-nominal behavior and the power dissipation of any thermal devices, especially TECs This paper outlines a number of the lessons learned over these two test campaigns with respect to the thermal design, model, and test configuration and presents recommendations for future tests.

Peabody, Hume↗

Plateaus and Sinuous Ridges as the Fingerprints of Lava Flow Inflation in the Eastern Tharsis Plains of Mars

The Tharsis Montes rift aprons are composed of outpourings of lava from chaotic terrains to the northeast and southwest flank of each volcano. Sinuous and branching channel networks that are present on the rift aprons suggest the possibility of fluvial processes in their development, or erosion by rapidly emplaced lavas, but the style of lava flow emplacement throughout rift apron development is not clearly understood. To better characterize the style of lava emplacement and role of fluvial processes in rift apron development, we conducted morphological mapping of the Pavonis Mons southwest rift apron and the eastern Tharsis plains using images from the High Resolution Imaging Science Experiment (HiRISE), Mars Orbiter Camera (MOC), Context Camera (CTX), Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) along with the Mars Orbiter Laser Altimeter (MOLA) Precision Experiment Data Records (PEDRs) and gridded data. Our approach was to: (1) search for depositional fans at the slope break between the rift apron and adjacent low slope plains; (2) determine if there is evidence that previously formed deposits might have been buried by plains units; (3) characterize the Tharsis plains morphologies east of Pavonis Mons; and (4) assess their relationship to the rift apron units. We have not identified topographically significant depositional fans, nor did we observe evidence to suggest that plains units have buried older rift apron units. Flow features associated with the rift apron are observed to continue across the slope break onto the plains. In this area, the plains are composed of a variety of small fissures and low shield vents around which broad channel-fed and tube-fed flows have been identified. We also find broad, flat-topped plateaus and sinuous ridges mixed among the channels, tubes and vents. Flat-topped plateaus and sinuous ridges are morphologies that are analogous to those observed on the coastal plain of Hawai'i, where lava flows have advanced from the volcano's several degree flank onto the nearly zero degree coastal plain. When local volumetric flow rates are low, flow fronts tend to spread laterally and often thicken via endogenous growth, or inflation, of the sheet-like flow units. If flow advance is restricted by existing topography into narrow pathways, inflation can be focused into sinuous, elongate ridges. The presence of plateaus and ridges-emplaced from the rift zones, across the plains to the east of Pavonis Mons-and a lack of fan-like features, or evidence for their burial, are consistent with rift apron lavas crossing a slope break with low local volumetric flow rates that led to inflation of sheet-like and tube-fed lava flows.

Bleacher, Jacob E.↗

The effects of thermal gradients on the Mars Observer Camera primary mirror

The paper discusses the effect of thermal gradients on the optical performance of the primary mirror of Mars Observer Camera (MOC), which will be launched on the Mars Observer spacecraft in September 1992. It was found that mild temperature gradients can have a large effect on the mirror surface figure, even for relatively low coefficient-of-thermal-expansion materials. However, in the case of the MOC primary mirror, it was found that the radius of curvature (ROC) of the reflective surface of the mirror changed in a nearly linear fashion with the radial temperature gradient, with little additional aberration. A solid-state ROC controller using the thermal gradient effect was implemented and verified.

Applewhite, Roger W.↗

Thermal History Mapping Technology for Turbine Engine Diagnostics

The infusion of ceramic matrix composites (CMCs) in next generation gas turbines represents daunting challenges as the failure of protective coating, known as Environmental Barrier Coating (EBC), means little remnant life of CMC components. Consequently reliable lifing is critical to the success of CMC components. Accurate thermal mapping of EBC in rig and engine test is of paramount importance because temperature is the most critical variable for EBC life. Current temperature measurement technologies include thermocouples, pyrometers, IR cameras, and thermal paints. Thermocouples require a passage to access the components and pyrometers and IR cameras require line-of-sight. Thermal paints are based on color-sensitive pigments that visually indicate the temperature that a component experienced. Thermal paints do not require line-of-sight, however, they have a low resolution and a limited temperature capability (~1400°C). Thermal history coating is based on oxide ceramic which luminesces when excited with a light source. The luminescence changes when the material's structure changes triggered by heat impact. The maximum temperature to which the material was exposed can be determined from the luminescence change. This paper describes the principles of this new technique and demonstrates its capabilities for EBCs exposed to excess of 1500°C.

Lee, Kang N.↗

Performance of Compact Pulsed Thermal Imaging System for In-Service Applications. Pulsed thermal tomography nondestructive examination of additively manufactured reactor materials and components

Additive manufacturing (AM) is an emerging method for cost-efficient fabrication of complex topology nuclear reactor parts from high-strength corrosion resistance alloys, such as stainless steel and Inconel. AM of metallic structures for nuclear energy applications is currently based on laser powder bed fusion (LPBF) process, which has the capability of melting metallic powder and net shaping the structures with relatively high precision. Some of the challenges with using LPBF method for nuclear manufacturing include the possibility of introducing pores into metallic structures. Integrity of AM structures needs to be evaluated nondestructively because material flaws could lead to premature failures due to creep in high temperature nuclear reactor environment. Currently, there exist limited capabilities to evaluate actual AM structures nondestructively. Pulsed Thermography (PT) imaging provides a capability for non-destructive evaluation (NDE) of sub-surface defects in arbitrary size structures. The PT method is based on recording material surface temperature transients with infrared (IR) camera following thermal pulse delivered on material surface with flash light. The PT method has advantages for NDE of actual AM structures because the method involves one-sided non-contact measurements and fast processing of large sample areas captured in one image. The data cube of PT measurements consists of surface temperature taken at sequential time intervals T(x,y,t). Material defects can be detected either by analyzing the thermograms T(x,y,t) data cube, or by using thermal tomography (TT) algorithm to obtain 3D spatial reconstruction of thermal effusivity e(x,y,z). To reduce the cost and enable in-service NDE in spatially constrained environment, it is highly desirable to develop PT with compact and inexpensive IR camera. Following initial qualification of an AM component for deployment in a nuclear reactor, a compact PT system can also be used for in-service nondestructive evaluation (NDE) applications. However, data cube obtained with PT based on compact IR camera suffers from strong thermal noises and loss of features due to relatively low sampling rate. In this report we describe two unsupervised machine learning (ML) algorithms for enhancement of PT images obtained with compact IR camera. In one approach, we introduce Sparse Coding Discrete Cosine Transform (SC/DCT) algorithm to remove additive white Gaussian noise (AWGN) from spatial thermal effusivity reconstructions. In another approach we introduce a Spatial Temporal Denoised Thermal Source Separation (STDTSS) ML algorithm to process thermograms. The STDTSS algorithm consists of spatial and temporal denoising using Gaussian and Savitzky–Golay filtering, followed by the matrix decomposition using Principal Component Analysis (PCA), and Independent Component Analysis (ICA) to automatically detect flaws. In the work described in this report, we constructed a compact PT system using a relatively small and low-cost FLIR A65 camera, consisting on uncooled microbolometer detector. Performance of SC/DCT algorithm was demonstrated on enhancing TT images of Inconel 718 AM plate. Performance of the STDTSS methods was investigated using thermography data obtained from imaging stainless steel 316L specimens produced with LPBF method with imprinted calibrated porosity defects.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗