Publications

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Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

Manufacturing of integrated circuits (ICs) using a split foundry process expands design space in IC fabrication by employing unique capabilities of multiple foundries and provides added security for IC designers [1] Defect localization and root cause analysis is critical to failure identification and implementation of corrective actions. In addition to split-foundry fabrication, the device addressed in this publication is .comprised of 8 metal layers, aluminum test pads, and tungsten thru-silicon vias (TSVs) making the circuit area > 68% metal. This manuscript addresses the failure analysis efforts involved in root cause analysis, failure analysis findings, and the corrective actions implemented to eliminate these failure mechanisms from occurring in future product.

The Rim-to-Rim Wearables At The Canyon for Health (R2R WATCH) study examines metrics recordable on commercial off the shelf (COTS) devices that are most relevant and reliable for the earliest possible indication of a health or performance decline. This is accomplished through collaboration between Sandia National Laboratories (SNL) and The University of New Mexico (UNM) where the two organizations team up to collect physiological, cognitive, and biological markers from volunteer hikers who attempt the Rim-to-Rim (R2R) hike at the Grand Canyon. Three forms of data are collected as hikers travel from rim to rim: physiological data through wearable devices, cognitive data through a cognitive task taken every 3 hours, and blood samples obtained before and after completing the hike. Data is collected from both civilian and warfighter hikers. Once the data is obtained, it is analyzed to understand the effectiveness of each COTS device and the validity of the data collected. We also aim to identify which physiological and cognitive phenomena collected by wearable devices are the most relatable to overall health and task performance in extreme environments, and of these ascertain which markers provide the earliest yet reliable indication of health decline. Finally, we analyze the data for significant differences between civilians’ and warfighters’ markers and the relationship to performance. This is a study funded by the Defense Threat Reduction Agency (DTRA, Project CB10359) and the University of New Mexico (The main portion of the R2R WATCH study is funded by DTRA. UNM is currently funding all activities related to bloodwork. DTRA, Project CB10359; SAND2017-1872 C). This paper describes the experimental design and methodology for the first year of the R2R WATCH project.

A human readiness levels (HRL) scale provides a framework to factor in the human dimension during technology development. This framework promotes careful consideration of the human as a part of the system throughout the product lifecycle. Insufficient attention to the human component of the system can lead to added costs, delayed deliverables, system failure, and even the loss of human life in high-consequence systems. We make the economic and technical justification for using an HRL scale by evaluating a reactive case study within a national laboratory. We create a historical technology readiness level (TRL) adoption roadmap to forecast a potential HRL adoption roadmap. We identify characteristics of organizations that are most likely to adopt the scale and conclude by recommending several project management tactics to ensure successful implementation.

Scattering environment conditions, such as fog, pose a challenge for many detection and surveillance active sensing operations in both ground and air platforms. For example, current autonomous vehicles rely on a range of optical sensors that are affected by degraded visual environments. Real-world fog conditions can vary widely depending on the location and environmental conditions during its creation. In our previous work we have shown benefits for increasing signal and range through scattering environments such as fog utilizing polarized light, specifically circular polarization. In this work we investigate the effect of changing fog particle sizes and distributions on polarization persistence for both circularly and linearly polarized light via simulation. We present polarization tracking Monte Carlo results for a range of realistic monodisperse particle sizes as well as varying particle size distributions as a model of scattering environments. We systematically vary the monodisperse particle size, mean particle size of a distribution, particle size distribution width, and number of distribution lobes (bi-modal), as they affect polarized light transmission through a scattering environment. We show that circular polarization signal persists better than linear polarization signal for most variations of the particle distribution parameters.

Scattering environment conditions, such as fog, pose a challenge for many detection and surveillance active sensing operations in both ground and air platforms. For example, current autonomous vehicles rely on a range of optical sensors that are affected by degraded visual environments. Real-world fog conditions can vary widely depending on the location and environmental conditions during its creation. In our previous work we have shown benefits for increasing signal and range through scattering environments such as fog utilizing polarized light, specifically circular polarization. In this work we investigate the effect of changing fog particle sizes and distributions on polarization persistence for both circularly and linearly polarized light via simulation. We present polarization tracking Monte Carlo results for a range of realistic monodisperse particle sizes as well as varying particle size distributions as a model of scattering environments. We systematically vary the monodisperse particle size, mean particle size of a distribution, particle size distribution width, and number of distribution lobes (bi-modal), as they affect polarized light transmission through a scattering environment. We show that circular polarization signal persists better than linear polarization signal for most variations of the particle distribution parameters.

Degraded visual environments are a serious concern for modern sensing and surveillance systems. Fog is of interest due to the frequency of its formation along our coastlines disrupting border security and surveillance. Fog presents hurdles in intelligence and reconnaissance by preventing data collection with optical systems for extended periods. We will present recent results from our work in operating optical systems in our controlled fog experimental chamber. This facility is a 180-foot-long, 10-foot-wide, and 10-foot-Tall structure that has over 60 spray nozzles to achieve uniform aerosol coverage with various particle size, distributions, and densities. We will discuss the physical formation of fog in nature and how our generated fog compares. In addition, we will discuss fog distributions and characterization techniques. We will investigate the biases of different methods and discuss the different techniques that are appropriate for realistic environments. Finally, we will compare the data obtained from our characterization studies against accepted models (e.g., MODTRAN) and validate the usage of this unique capability as a controlled experimental realization of natural fog formations. By proving the capability, we will enable the testing and validation of future fog penetrating optical systems and providing a platform for performing optical propagation experimentation in a known, stable, and controlled environment.

Children with autism spectrum disorders (ASD) and their unaffected siblings (US) are frequent targets of social bullying, which leads to severe physical, emotional, and social consequences. Understanding the risk factors is essential for developing preventative measures. We suggest that one such risk factor may be a difficulty to discriminate different biological body movements (BBM), a task that requires fast and flexible processing and interpretation of complex visual cues, especially during social interactions. Deficits in cognition of BBM have been reported in ASD. Since US display an autism endophenotype we expect that they will also display deficits in social interpretation of BBM. Methods. Participants: 8 US, 8 matched TD children, age 7-14; Tasks/Measurements: Social Blue Man Task: Narrative interpretation with a Latent Dirichlet Allocation [LDA] analysis; Social Experience Questionnaires with children and parents. Results. The US displayed as compared to TD: (i) low self-awareness of social bullying in contrast to high parental reports; (ii) reduced speed in identifying social cues; (iii) lower quality and repetitious wording in social interaction narratives (LDA). Conclusions. US demonstrate social endophenotype of autism reflected in delayed identification, interpretation and verbalization of social cues; these may constitute a high risk factor for becoming a victim of social bullying.

We present a new, non-destructive electrical technique, Power Spectrum Analysis (PSA). PSA as described here uses off-normal biasing, an unconventional way of powering microelectronics devices. PSA with off-normal biasing can be used to detect subtle differences between microelectronic devices. These differences, in many cases, cannot be detected by conventional electrical testing. In this paper, we highlight PSA applications related to aging and counterfeit detection.

We present a new, non-destructive electrical technique, Power Spectrum Analysis (PSA). PSA as described here uses off-normal biasing, an unconventional way of powering microelectronics devices. PSA with off-normal biasing can be used to detect subtle differences between microelectronic devices. These differences, in many cases, cannot be detected by conventional electrical testing. In this paper, we highlight PSA applications related to aging and counterfeit detection.

Recent Magnetized Liner Inertial Fusion experiments at the Sandia National Laboratories Z pulsed power facility have featured a PDV (Photonic Doppler Velocimetry) diagnostic in the final power feed section for measuring load current. In this paper, we report on an anomalous pressure that is detected on this PDV diagnostic very early in time during the current ramp. Early time load currents that are greater than both B-dot upstream current measurements and existing Z machine circuit models by at least 1 MA would be necessary to describe the measured early time velocity of the PDV flyer. This leads us to infer that the pressure producing the early time PDV flyer motion cannot be attributed to the magnetic pressure of the load current but rather to an anomalous pressure. Using the MHD code ALEGRA, we are able to compute a time-dependent anomalous pressure function, which when added to the magnetic pressure of the load current, yields simulated flyer velocities that are in excellent agreement with the PDV measurement. We also provide plausible explanations for what could be the origin of the anomalous pressure.

The thermal degradation of two polyurethane elastomers was investigated via thermal gravimetric analysis coupled with gas chromatography/ma ss spectrometry. Decomposition occur s in a multi - step fashion with similar onset temperatures for both materials. Apparent activation energy plots were calculated inside Model - Free Kinetics software and utilized to construct conversion and isothermal conversion tables . These tables predicted material degradation as a function of temperature and time. Isothermal experiments were performed and found to be in good agreement with the predictions made from the Model - Free Kinetic s software package. Volatile products evolved during the multistep decomposition were captured at various times and analyzed using the coupled gas chromatography/mass spectrometry system . This analysis demonstrated strong correlation between the degradation products and known decomposition mechanisms for polyurethanes.

Since our last paper, cyber attacks have shown no evidence of declining in frequency or sophistication. We claim that applying isolation zones is an effective way to defend cyber systems; our team proposes a simulation and mathematical model that provide numerical data that supports this claim. This paper extends our earlier cyber zone defense (CZD) framework in two critical ways. First, we relax our assumption that zones completely isolate nodes and consider interzone boundaries to be porous. Second, we investigate methods to estimate one of the legacy parameters inherited from our earlier work and the new porosity parameter. The extended simulation and model more closely approximate real world cyber systems and have lower residuals than our previous investigation.

Silicon-based metal-oxide-semiconductor quantum dots are prominent candidates for high-fidelity, manufacturable qubits. Due to silicon's band structure, additional low-energy states persist in these devices, presenting both challenges and opportunities. Although the physics governing these valley states has been the subject of intense study, quantitative agreement between experiment and theory remains elusive. Here, we present data from an experiment probing the valley states of quantum dot devices and develop a theory that is in quantitative agreement with both this and a recently reported experiment. Through sampling millions of realistic cases of interface roughness, our method provides evidence that the valley physics between the two samples is essentially the same.

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The Sandia Data Archive (SDA) format is special implementation the HDF5 (Hierarchal Data Format, version 5) standard. Archive files store data in records identified with a unique text label. Primitive records store numeric, logical, and character arrays of arbitrary size and dimensionality. Compound records store composite MAT- LAB variables--cell arrays, structures, and objects--with arbitrary nesting. External records allow text/binary files to be stored alongside archived data or division of a large file into smaller archives for transmission. This report documents version 1.1 of the SDA standard, which adds support for structure and object arrays. The basic principles of SDA remain unchanged from version 1.0, with minor enhancements and bug fixes. The Sandia Mat lab AnalysiS Hierarchy (SMASH) toolbox uses SDA extensively; support utilities from the toolbox are highlighted here. Although the SDA format is designed around MATLAB, its use of HDF5 allows adoption in other computer languages.

We present simulation and experimental results showing circular polarization is more tolerant of optical collection geometry (field of view and collection area) variations than linear polarization for forward-scattering environments. Circular polarization also persists superiorly in the forward-scattering environment compared to linear polarization by maintaining its degree of polarization better through increasing optical thicknesses. In contrast, both linear and circular polarizations are susceptible to collection geometry variations for isotropic-scattering (Rayleigh regime) environments, and linear polarization maintains a small advantage in polarization persistence. Simulations and measurements are presented for laboratory-based environments of polystyrene microspheres in water. Particle diameters were 0.0824 μm (for isotropic-scattering) and 1.925 μm (for forward-scattering) with an illumination wavelength of 543.5 nm.