317 research outputs found

    Remote robot manipulator coupled with remote-controlled guide vehicle for soil sampling in hazardous waste sites

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    The important initial step for remediation of hazardous waste is contaminant analysis since the cleanup operation can not begin until the contaminants in hazardous waste sites have been clearly identified. Ames Laboratory, one of the U.S. Department of Energy sites, has developed a robotic sampling system for automation of real-time contaminant analysis in situ which will provide the advantage of lowering the cost per sample, eliminating personnel exposure to hazardous environments, and allowing quicker results. Successful accomplishment of real-time contaminant analysis will require a remote manipulator to perform the sampling tasks in remote and unstructured surroundings, and a remote-controlled guide vehicle to move a remote manipulator into the desired sampling location;This thesis focuses on the design and construction of a remote-controlled guide vehicle to move the robotic sampling system into the contaminated field to obtain soil samples at the desired locations, the development of an integrated dynamic model of a remote manipulator, the identification of dynamic parameters in the integrated dynamic model, and the design of a mobile robotic sampling system. A four-wheeled vehicle prototype has been constructed and its performance tested manually in the field to verify the design requirements. To remotely control the vehicle, mechanical requirements to activate the brake, throttle, transmission, and steering linkages were determined based on experimental results. A teleoperated control utilizing hundred feet long umbilical cords was first employed to remotely control the vehicle. Next, the vehicle was modified to remotely operate in the field by radio control without the aid of long umbilical cords, satisfying all the design specifications;To reduce modeling error in the robotic system, the integrated dynamic system comprised of a remote manipulator (located on a trailer pulled by the remote-controlled guide vehicle) and its drive system has been modeled. The friction model as a function of velocity is included. The dynamic parameters such as velocity-dependent friction and gravity torque in the integrated dynamic model have been determined based on experimental results;Finally, a robotic arm, a sampling tool, and a soil recovery fixture for a mobile robotic sampling system to be mounted on the remote-controlled guide vehicle have been designed and analyzed. The integrated dynamic model for the robotic arm (mounted on the remote-controlled guide vehicle) and its drive system has also been developed

    Fresnel-type Solid Immersion Lens for efficient light collection from quantum defects in diamond

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    Quantum defects in diamonds have been studied as a promising resource for quantum science. The subtractive fabrication process for improving photon collection efficiency often require excessive milling time that can adversely affect the fabrication accuracy. We designed and fabricated a Fresnel-type solid immersion lens using the focused ion beam. For a 5.8 um-deep Nitrogen-vacancy (NV-) center, the milling time was highly reduced (1/3 compared to a hemispherical structure), while retaining high photon collection efficiency (> 2.24 compared to a flat surface). In numerical simulation, this benefit of the proposed structure is expected for a wide range of milling depths.Comment: 16 pages, 9 figure

    Neutron XS Library Generation of ENDF/B-VIII.0 for MOC code STREAM and Monte Carlo code MCS

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    Department of Nuclear EngineeringIn this paper, the verification and validation of ENDF/B-VIII.0 XS data uses STREAM code and MCS code. ENDF/B-VIII.0 XS data compare with ENDF/B-VII.1 XS data. In the case of a library of unique nuclear data for STREAM, the neutron transport analysis code, ENDF files for each nuclide were produced in Group-wise XS using NJOY code system, and in the second step, STREAM XS Library was produced using STREAM library production system, NTOS. Using this multi-group nuclear data production system, STREAM XS library was produced for all nuclides based on ENDF/B-VII.1 nuclear data library and ENDF/B-VIII.0 nuclear data library. To assess the accuracy of the library, STREAM code and MCS code were simultaneously compared for each ENDF version. For the validation, each of benchmarks are used, NCA benchmark, VERA benchmark and ICSBEP benchmark. NCA benchmark analysis, which is the critical experiments performed at the Toshiba Nuclear Critical Assembly (NCA) critical facility. Each benchmark was compared in STREAM and MCS, and NCA benchmark analysis include tungsten gray rods demonstrates the accuracy of STREAM code???s pin power distribution. STREAM code nuclear source used the both of ENDF/B-VIII.0 and ENDF/B-VII.1, and their results compared with each of MCS code results. When STREAM's results were compared for each version of ENDF, NCA benchmark found that the difference of the effective multiplication factor was within 100 pcm for the problem, confirming that ENDF/B-VIII.0 STREAM XS Library was properly produced. Also in case of VERA benchmark and ICSBEP benchmark, the difference of the effective multiplication factor was within 300 pcm for the problem with ENDF/B-VII.1 XS Library results and ENDF/B-VIII.0 XS Library results. The accuracy of STREAM results was verified by comparing them with the MCS results of the same problem for each result.ope

    Smooth Model Predictive Path Integral Control without Smoothing

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    We present a sampling-based control approach that can generate smooth actions for general nonlinear systems without external smoothing algorithms. Model Predictive Path Integral (MPPI) control has been utilized in numerous robotic applications due to its appealing characteristics to solve non-convex optimization problems. However, the stochastic nature of sampling-based methods can cause significant chattering in the resulting commands. Chattering becomes more prominent in cases where the environment changes rapidly, possibly even causing the MPPI to diverge. To address this issue, we propose a method that seamlessly combines MPPI with an input-lifting strategy. In addition, we introduce a new action cost to smooth control sequence during trajectory rollouts while preserving the information theoretic interpretation of MPPI, which was derived from non-affine dynamics. We validate our method in two nonlinear control tasks with neural network dynamics: a pendulum swing-up task and a challenging autonomous driving task. The experimental results demonstrate that our method outperforms the MPPI baselines with additionally applied smoothing algorithms.Comment: Accepted to IEEE Robotics and Automation Letters (and IROS 2022). Our video can be found at https://youtu.be/ibIks6ExGw

    Attentional Avoidance for Guilty Knowledge Among Deceptive Individuals

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    The purpose of the present study is to differentiate between innocent suspects who have knowledge of crime information and guilty suspects. The study investigated eye-movement differences among three groups: a guilty group who took part in a mock crime, an innocent-aware group who did not commit a mock crime but were exposed to the crime stimuli, and an innocent-unaware group who neither committed a mock crime nor had crime-relevant information. Each group's eye movements were tracked while all participants viewed stimuli (crime-relevant, crime-irrelevant, and neutral). The results revealed that the guilty group not only viewed all stimuli later than the other groups, they also viewed crime-relevant and crime-irrelevant stimuli for a shorter time period than the innocent-aware group; the innocent-aware group focused their attention on crime-relevant and crime-irrelevant stimuli longer than neutral stimuli, and the innocent-unaware group showed no differences in their attention focus among all types of stimuli. This present study suggests that guilty individuals show attentional avoidance from all stimuli in a lie detection situation, whereas innocent-aware and innocent-unaware individuals did not show avoidance responses

    Algorithmic decomposition for efficient multiple nuclear spin detection in diamond

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    Efficiently detecting and characterizing individual spins in solid-state hosts is an essential step to expand the fields of quantum sensing and quantum information processing. While selective detection and control of a few 13C nuclear spins in diamond have been demonstrated using the electron spin of nitrogen-vacancy (NV) centers, a reliable, efficient, and automatic characterization method is desired. Here, we develop an automated algorithmic method for decomposing spectral data to identify and characterize multiple nuclear spins in diamond. We demonstrate efficient nuclear spin identification and accurate reproduction of hyperfine interaction components for both virtual and experimental nuclear spectroscopy data. We conduct a systematic analysis of this methodology and discuss the range of hyperfine interaction components of each nuclear spin that the method can efficiently detect. The result demonstrates a systematic approach that automatically detects nuclear spins with the aid of computational methods, facilitating the future scalability of devices.Comment: 4 figures, 2 table

    Enhanced osteogenesis of human urine-derived stem cells by direct delivery of 30Kc19α–Lin28A protein

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    Urine-derived stem cells (USCs) are a promising source for regenerative medicine because of their advantages such as easy and non-invasive collection from the human body, stable expansion, and the potential to differentiate into multiple lineages, including osteoblasts. In this study, we propose a strategy to enhance the osteogenic potential of human USCs using Lin28A, a transcription factor that inhibits let-7 miRNA processing. To address concerns regarding the safety of foreign gene integration and potential risk of tumorigenicity, we intracellularly delivered Lin28A as a recombinant protein fused with a cell-penetrating and protein-stabilizing protein, 30Kc19α. 30Kc19α–Lin28A fusion protein exhibited improved thermal stability and was delivered into USCs without significant cytotoxicity. 30Kc19α–Lin28A treatment elevated calcium deposition and upregulated several osteoblast-specific gene expressions in USCs derived from multiple donors. Our results indicate that intracellularly delivered 30Kc19α–Lin28A enhances the osteoblastic differentiation of human USCs by affecting the transcriptional regulatory network involved in metabolic reprogramming and stem cell potency. Therefore, 30Kc19α–Lin28A may provide a technical advancement toward developing clinically feasible strategies for bone regeneration
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