Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “BOS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Materials Data on Th(BOs)4 by Materials Project

Th(OsB)4 crystallizes in the tetragonal P4_2/n space group. The structure is three-dimensional. Th4+ is bonded in a 8-coordinate geometry to eight equivalent Os1- atoms. All Th–Os bond lengths are 3.23 Å. Os1- is bonded in a 4-coordinate geometry to two equivalent Th4+ and four equivalent B atoms. There are a spread of Os–B bond distances ranging from 2.14–2.19 Å. B is bonded in a 5-coordinate geometry to four equivalent Os1- and one B atom. The B–B bond length is 1.80 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th(BOs)2 by Materials Project

Th(OsB)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Th4+ is bonded in a 4-coordinate geometry to four equivalent Os2- atoms. All Th–Os bond lengths are 3.04 Å. Os2- is bonded in a 4-coordinate geometry to two equivalent Th4+ and four equivalent B atoms. There are two shorter (2.10 Å) and two longer (2.18 Å) Os–B bond lengths. B is bonded to four equivalent Os2- atoms to form a mixture of distorted edge and corner-sharing BOs4 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(BOs)4 by Materials Project

U(OsB)4 crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. U6+ is bonded in a 12-coordinate geometry to twelve equivalent Os+1.50- atoms. There are a spread of U–Os bond distances ranging from 2.93–3.27 Å. Os+1.50- is bonded in a 5-coordinate geometry to three equivalent U6+ and five equivalent B atoms. There are a spread of Os–B bond distances ranging from 2.16–2.28 Å. B is bonded in a 6-coordinate geometry to five equivalent Os+1.50- and one B atom. The B–B bond length is 1.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on La2Al(BOs)2 by Materials Project

La2Al(OsB)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 6-coordinate geometry to one Os+1.50- and five B3- atoms. The La–Os bond length is 3.20 Å. There are a spread of La–B bond distances ranging from 2.77–3.03 Å. In the second La3+ site, La3+ is bonded in a 4-coordinate geometry to four B3- atoms. There are a spread of La–B bond distances ranging from 2.88–3.11 Å. There are two inequivalent Os+1.50- sites. In the first Os+1.50- site, Os+1.50- is bonded in a 5-coordinate geometry to three equivalent Al3+ and two B3- atoms. There are a spread of Os–Al bond distances ranging from 2.65–2.77 Å. There are one shorter (2.02 Å) and one longer (2.13 Å) Os–B bond lengths. In the second Os+1.50- site, Os+1.50- is bonded in a 4-coordinate geometry to one La3+, one Al3+, and three B3- atoms. The Os–Al bond length is 2.58 Å. There are one shorter (2.01 Å) and two longer (2.13 Å) Os–B bond lengths. Al3+ is bonded in a 4-coordinate geometry to four Os+1.50- atoms. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded to five La3+ and two Os+1.50- atoms to form a mixture of distorted edge and corner-sharing BLa5Os2 pentagonal bipyramids. In the second B3- site, B3- is bonded in a 7-coordinate geometry to four La3+ and three Os+1.50- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on Pr(BOs)4 by Materials Project

Pr(OsB)4 crystallizes in the tetragonal P4_2/n space group. The structure is three-dimensional. Pr3+ is bonded in a 8-coordinate geometry to eight equivalent Os+0.75- atoms. There are four shorter (3.22 Å) and four longer (3.23 Å) Pr–Os bond lengths. Os+0.75- is bonded in a 4-coordinate geometry to two equivalent Pr3+ and four equivalent B atoms. There are a spread of Os–B bond distances ranging from 2.14–2.18 Å. B is bonded in a 5-coordinate geometry to four equivalent Os+0.75- and one B atom. The B–B bond length is 1.78 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd(BOs)2 by Materials Project

Nd(OsB)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Nd3+ is bonded in a 4-coordinate geometry to four equivalent Os+1.50- atoms. All Nd–Os bond lengths are 3.05 Å. Os+1.50- is bonded in a 4-coordinate geometry to two equivalent Nd3+ and four equivalent B atoms. There are two shorter (2.10 Å) and two longer (2.18 Å) Os–B bond lengths. B is bonded to four equivalent Os+1.50- atoms to form a mixture of distorted edge and corner-sharing BOs4 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Gd(BOs)2 by Materials Project

Gd(OsB)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Gd3+ is bonded in a 4-coordinate geometry to four equivalent Os+1.50- atoms. All Gd–Os bond lengths are 3.02 Å. Os+1.50- is bonded in a 4-coordinate geometry to two equivalent Gd3+ and four equivalent B atoms. There are two shorter (2.08 Å) and two longer (2.18 Å) Os–B bond lengths. B is bonded in a 4-coordinate geometry to four equivalent Os+1.50- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2026

BOS Gas Detection Pipeline (Integrated System for Optical Hydrogen Detection Using Background Oriented Schlieren and Machine Learning) [SWR-26-007]

This software is the world's first integrated background oriented schlieren and machine learning-based leak detection system. The system provides real time visualization of gas leaks and machine learning interpenetration of leak severity. The software is supplemented by SWR-25-177, "gpu_piv (Graphics Processing Unit Accelerated Background Oriented Schlieren Algorithm", also developed by the National Laboratory of the Rockies. SEE DOECODE ID 182832.

Palin, Ian [National Laboratory of the Rockies (NL↗
NASA NTRS2016

Background Oriented Schlieren (BOS) of a Supersonic Aircraft in Flight

This article describes the development and use of Background Oriented Schlieren on a full-scale supersonic jet in flight. A series of flight tests was performed in October, 2014 and February 2015 using the flora of the desert floor in the Supersonic Flight Corridor on the Edwards Air Force Base as a background. Flight planning was designed based on the camera resolution, the mean size and color of the predominant plants, and the navigation and coordination of two aircraft. Software used to process the image data was improved with additional utilities. The planning proved to be effective and the vast majority of the passes of the target aircraft were successfully recorded. Results were obtained that are the most detailed schlieren imagery of an aircraft in flight to date.

Schlieren imaging↗
NASA NTRS2016

Comparison of Cross Correlation and Optical Flow Methods for Processing Retroreflective and Natural Background BOS Data

Background oriented schlieren images have historically been generated by calculating the observed pixel displacement between an image pair using normalized cross-correlation methods. This work uses optical flow data reduction methods to solve the displacement fields. A well established method used in the computer vision community, optical flow is the apparent brightness motion in an image sequence. The regularization method of Horn and Schunck is used to create schlieren images using two data sets: a supersonic shockjet plume interaction at the NASA Ames Unitary Plan Wind Tunnel, and a transonic flight test of a T-38 using a naturally occurring background performed in conjunction with NASA Ames and Armstrong research centers. Results are presented and contrasted with those using normalized cross-correlation methods. The optical flow images are found to provided significantly more detail at a decreased computational time.

schlieren↗
NASA NTRS2016

Background Oriented Schlieren (BOS) of a Supersonic Aircraft In Flight

This article describes the development and use of Background Oriented Schlieren on a full-scale supersonic jet in flight. A series of flight tests was performed in October, 2014 and February 2015 using the flora of the desert floor in the Supersonic Flight Corridor on the Edwards Air Force Base as a background. Flight planning was designed based on the camera resolution, the mean size and color of the predominant plants, and the navigation and coordination of two aircraft. Software used to process the image data was improved with additional utilities. The planning proved to be effective and the vast majority of the passes of the target aircraft were successfully recorded. Results were obtained that are the most detailed schlieren imagery of an aircraft in flight to date.

Heineck, James T.↗
NASA NTRS2019

Real-Time Background Oriented Schlieren: Catching Up With Knife Edge Schlieren

Background Oriented Schlieren (BOS) is a widely used technique that provides density gradient information in flow fields of interest, without imposing stringent optical quality requirements on the facility/experiment windows and/or optics used in the BOS setup. Typically, the BOS reference image is acquired before the test begins (flow off) and then the "live" image data are acquired during the actual testing/experiment (flow on). The raw BOS image data, while displayed in real-time as they are acquired from the camera, unfortunately provide little if any visual indication of the density gradients in the flow. Generally, the "live" images must be processed off-line after the testing is completed, providing no indication of the success of the BOS setup and no feedback on the operational success of the test. Advances in computer processing hardware enables the implementation of real-time processing and display of the BOS image data. Two different approaches to implementing the real-time BOS (RT-BOS) processing capability are described herein. First, a traditional multi-core Central Processing Unit (CPU) based approach using scheduled parallel threads is used to build a RT-BOS processing engine. In the second approach, a Graphical Processing Unit (GPU) approach is used to costruct a RT-BOS processing engine. Generally, high core count CPU processors can provide a useful processing rate for RT-BOS. However, the GPU based approach exceeds the processing capability of the CPU approach, at a fraction of the cost. The GPU approach places no restrictions on the Host PC processing capability, except that it be capable of acquiring the BOS image data from the camera in real-time.

Wernet, Mark P.↗
DOE OSTI2014

Land-Based Wind Plant Balance-of-System Cost Drivers and Sensitivities (Poster)

With Balance of System (BOS) costs contributing up to 30% of the installed capital cost, it is fundamental to understand the BOS costs for wind projects as well as potential cost trends for larger turbines. NREL developed a BOS model using project cost estimates developed by industry partners. Aspects of BOS covered include engineering and permitting, foundations for various wind turbines, transportation, civil work, and electrical arrays. The data introduce new scaling relationships for each BOS component to estimate cost as a function of turbine parameters and size, project parameters and size, and geographic characteristics. Based on the new BOS model, an analysis to understand the non‐turbine wind plant costs associated with turbine sizes ranging from 1-6 MW and wind plant sizes ranging from 100-1000 MW has been conducted. This analysis establishes a more robust baseline cost estimate, identifies the largest cost components of wind project BOS, and explores the sensitivity of the capital investment cost and the levelized cost of energy to permutations in each BOS cost element. This presentation shows results from the model that illustrate the potential impact of turbine size and project size on the cost of energy from US wind plants.

17 WIND ENERGY↗
NASA NTRSDate not supplied

Accuracy of Center of Pressure Determination via Motion Capture

BACKGROUND: This study was conducted to support the stability assessment for tasks in lunar gravity and exercises on a Vibration Isolation and Stabilization (VIS) system in microgravity based on the dynamic feasibility criterion of whether the calculated position of the center of pressure (COP) falls within the base of support (BOS) which outlines the subject’s feet. Motion capture data combined with biomechanical modeling and simulation allows the forces and moments between the human and the VIS platform to be computed and the position of the COP as well as the location and shape of the BOS to be determined. The goal of this study was to assess the accuracy of the COP trajectory calculated using motion capture-based data. METHODS AND RESULTS: To obtain the dynamic quantities from which COP is calculated, motion capture data is first collected in the 1g lab environment by recording the trajectories of passive retroreflective markers placed on a subject during exercise or performance of a given task. The OpenSim [1] inverse kinematics (IK) tool is used to fit a scaled subject model to recorded marker trajectories while minimizing marker error to obtain joint angles. Then, a custom OpenSim plugin [2] is used to determine the subject’s time-varying moment of inertia and its time derivative, center of mass (CM) position, velocity, and acceleration, as well as the angular momentum and its time derivative relative to the subject’s CM. Some of these quantities are not needed for modeling tasks performed on a stationary lunar surface but, due to the moving exercise platform, are needed to model VIS response to the subject’s motion. Hand positions, used in calculating a cable force if present, are recorded as well. These quantities are used to calculate the total force (F ⃗^((plate) )) and moment (M ⃗^((plate) )) exerted by the lunar surface or the VIS plate on the subject’s shoe soles. COP is then calculated from the following equations: r_x^((cop) )= M_z^((plate) )/F_y^((plate) ) and r_z^((cop) )= 〖-M〗_x^((plate) )/F_y^((plate) ), where the y axis is normal to the surface. COP accuracy for feasibility assessments is then determined by whether it falls within the BOS, which is also computed by the plugin. To study the accuracy of COP calculated from motion capture, we first investigated whether COP remained within the BOS, as it must, for exercises performed in the 1g lab environment. Standard exercises such as back squat and deadlift were analyzed, as well as more explosive exercises including hang clean and press. Cases in which the COP exited the BOS indicated that COP accuracy required further investigation. In this study, an exercise device with cables was used, so cable force modeling accuracy should also be considered. In a separate study, we collected motion capture and force plate data for twenty-seven motions not involving an exercise device. About a third were genuine countermeasures exercises (e.g., hang clean and press), some were relevant for lunar tasks (e.g., object pick up), and the rest were of a “unit test” nature (e.g., swaying back and forth or side to side). Motion capture-based COP positions were compared with force plate measured COP. We found that while force plate measured COP remained within the BOS, motion capture-based COP was observed to briefly exit the BOS on occasion. Techniques to mitigate IK artifacts and filtering of calculated data could be used to improve the agreement of calculated and measured results, resolving excursions from the BOS within this dataset. The mean error between calculated and measured COP was found to be less than 6 mm. Additionally, we derived and investigated equations for the COP in terms of the cable force, cable location, as well as the human CM position, acceleration, and angular momentum with respect to the CM, and analyzed them for sensitivity to errors in individual quantities. Several were found, but the most significant one was that when the vertical force on the feet approaches zero, indicating a near-detachment or ‘jump off’ condition, errors are amplified. This is consistent with the observation that in the absence of pressure, the concept of the center of pressure would become meaningless.

C A Bell↗
NASA NTRS1978

Cost of photovoltaic energy systems as determined by balance-of-system costs

The effect of the balance-of-system (BOS), i.e., the total system less the modules, on photo-voltaic energy system costs is discussed for multikilowatt, flat-plate systems. Present BOS costs are in the range of 10 to 16 dollars per peak watt (1978 dollars). BOS costs represent approximately 50% of total system cost. The possibility of future BOS cost reduction is examined. It is concluded that, given the nature of BOS costs and the lack of comprehensive national effort focussed on cost reduction, it is unlikely that BOS costs will decline greatly in the next several years. This prognosis is contrasted with the expectations of the Department of Energy National Photovoltaic Program goals and pending legislation in the Congress which require a BOS cost reduction of an order of magnitude or more by the mid-1980s.

Rosenblum, L.↗