Analyzing the discharge regime of a large tropical river through remote sensing, ground-based climatic data, and modeling

This study demonstrates the potential for applying passive microwave satellite sensor data to infer the discharge dynamics of large river systems using the main stem Amazon as a test case. The methodology combines (1) interpolated ground-based meteorological station data, (2) horizontally and vertically polarized temperature differences (HVPTD) from the 37-GHz scanning multichannel microwave radiometer (SMMR) aboard the Nimbus 7 satellite, and (3) a calibrated water balance/water transport model (WBM/WTM). Monthly HVPTD values at 0.25° (latitude by longitude) resolution were resampled spatially and temporally to produce an enhanced HVPTD time series at 0.5° resolution for the period May 1979 through February 1985. Enhanced HVPTD values were regressed against monthly discharge derived from the WBM/WTM for each of 40 grid cells along the main stem over a calibration period from May 1979 to February 1983 to provide a spatially contiguous estimate of time-varying discharge. HVPTD-estimated flows generated for a validation period from March 1983 to February 1985 were found to be in good agreement with both observed arid modeled discharges over a 1400-km section of the main stem Amazon. This span of river is bounded downstream by a region of tidal influence and upstream by low sensor response associated with dense forest canopy. Both the WBM/WTM and HVPTD-derived flow rates reflect the significant impact of the 1982–1983 El Niño-;Southern Oscillation (ENSO) event on water balances within the drainage basin

Advanced Camera Lowering Device for ITS Maintenance

IA 65A0560 Task 3213The California Department of Transportation (Caltrans), in an effort to satisfy mandated Intelligent Transportation System (ITS) performance goals and consistency with MAP-21 performance management targets, is deploying an increasing number of Closed-Circuit TV (CCTV) cameras to monitor traffic and conditions on California\u2019s roadways. These CCTV cameras are typically mounted along the highway on top of high poles and need to be accessed periodically for service and repair to keep these sophisticated systems functional. Many of these Caltrans camera system sites are difficult to access due to traffic hazards, roadside obstacles, and greater pole heights. Challenging access sites like these require additional time, cost, and exposure to unsafe conditions, which can contribute to delayed or deferred camera maintenance and repairs. Caltrans is expanding their application of pole-mounted Camera Lowering Devices (CLDs) systems in an effort to facilitate access to these problematic camera sites. Caltrans commonly deploys Halo-style CLD products. This research introduces Caltrans to the use of a detachable type of CLD product that offers additional benefits, such as eliminating the potential of binding, reducing communication cabling requirements, allowing the mounting of ancillary items such as antennas and microwave vehicle detection systems (MVDS), and supporting the retrofitting of existing camera poles. This research project supports the deployment and evaluation of both an internal and external MG2 CLD systems on Caltrans highways. This report documents the installation, training, and performance of these research MG2 systems in association with Caltrans District 3 Maintenance and Transportation Management Center (TMC) personnel. These MG2 CLD systems have proven to be easy to use, performed effectively, and provide significant cost and safety benefits to Caltrans maintenance when accessing ITS camera systems on the highway. Based on the successful deployment of these MG2 CLD systems, it is the recommendation of this report that Caltrans consider the qualification and expanded use of the MG2 CLD systems in the future

Hybrid HVDC circuit breaker with self-powered gate drives

The ever increasing electric power demand and the advent of renewable energy sources have revived the interest in high-voltage direct current (HVDC) multi-terminal networks. However, the absence of a suitable circuit breaker or fault tolerant VSC station topologies with the required characteristics (such as operating speed) have, until recently, been an obstacle in the development of large scale multi-terminal networks for HVDC. This paper presents a hybrid HVDC circuit breaker concept which is capable of meeting the requirements of HVDC networks. Simulation results are presented which are validated by experimental results taken from a 2.5kV, 700A rated laboratory prototype

Summertime surface energy balance fluxes at two Beijing sites

Summertime (June to August 2015) radiative and turbulent heat fluxes were measured concurrently at two sites (urban and suburban) in Beijing. The urban site has slightly lower incoming and outgoing shortwave radiation, lower atmospheric transmissivity and a lower surface albedo compared to the suburban site. Both sites receive similar incoming longwave radiation. Although the suburban site had larger daytime outgoing longwave radiation (L_↑), differences in the daily mean L_↑ values are small, as the urban site has higher nocturnal L_↑. Overall, both the midday and daily mean net all-wave radiation (Q^*) for the two sites are nearly equal. However, there are significant differences between the sites in the surface energy partitioning. The urban site has smaller turbulent sensible heat (Q_H) (21-25% of Q^* (midday – daily)) and latent heat (Q_E) fluxes (21-45% of Q^*). Whereas, the suburban proportions of Q^* are Q_H 32-32% and Q_E 39-66%. The daily (midday) mean Bowen ratio (Q_H⁄Q_E ) was 0.56 and 0.49 (0.98 and 0.83) for the urban and suburban sites, respectively. These values are low compared to other urban and suburban areas with similar or larger fractions of vegetated cover. Likely these are caused by the widespread external water use for road cleaning/wetting, greenbelts, and air conditioners. Our suburban site has quite different land cover to most previous suburban studies as crop irrigation supplements rainfall. These results are important in enhancing our understanding of surface–atmosphere energy exchanges in Chinese cities, and can aid the development and evaluation of urban climate models and inform urban planning strategies in the context of rapid global urbanization and climate change

Initial optical transition radiation measurements of the electron beam for the Boeing Free-Electron Laser experiment

The potential for characterization of electron beams at {approximately}100 MeV at the Boeing Free-Electron Laser (FEL) facility by optical transition radiation (OTR) techniques has been demonstrated as an important complement to other diagnostic means. Electron beam properties such as spatial profile and position, current intensity, emittance, and energy were made accessible in an on-line manner. Initial examples including transport through the 5-m wiggler and the resolution of Cerenkov radiation and spontaneous emission radiation competitive sources are discussed. 11 refs., 13 figs

Data-Driven Analysis of Departure Procedures for Aviation Noise Mitigation

13-C-AJFF-GIT-054This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license https://creativecommons.org/licenses/by/4.0/. The paper first appeared in Engineering Proceedings. Citation: Bhanpato, J.; Puranik, T.G.; Mavris, D.N. Data-Driven Analysis of Departure Procedures for Aviation Noise Mitigation. Eng. Proc. 2021, 13, 2. https://doi.org/10.3390/ engproc2021013002The mitigation of aviation environmental effects is one of the key requirements for sustainable aviation growth. Among various mitigation strategies, Noise Abatement Departure Procedures (NADPs) are a popular and effective measure undertaken by several operators. However, a large variation in departure procedures is observed in real operations. This study demonstrates the use of OpenSky ADS-B departure data for comparison and quantification of the differences in trajectories and the resulting community noise impact between real-world operations and NADPs. Trajectory comparison is accomplished in order to gain insights into the similarity between NADPs and real-world procedures. Clustering algorithms are employed to identify representative departure procedures, enabling efficient high-fidelity noise modeling. Finally, noise results are compared in order to quantify the difference in environmental impacts arising from variability in real-world trajectories. The methodology developed enables more efficient and accurate environmental analyses, thereby laying the foundation for future impact assessment and mitigation efforts

Measurements of Nitrile Rubber Absorption of Hydrocarbons: Trends for Sustainable Aviation Fuel Compatibility

13-C-AJFE-UD-026, 035This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as: Measurements of Nitrile Rubber Absorption of Hydrocarbons: Trends for Sustainable Aviation Fuel Compatibility Conor Faulhaber, Christopher Borland, Randall Boehm, and Joshua Heyne Energy & Fuels 2023 37 (13), 9207-9219. https://doi.org/10.1021/acs.energyfuels.3c00781he commercial aviation sector is seeking to reach net zero CO2 emissions by 2050, with sustainable aviation fuel (SAF) being the most important lever. However, SAF is currently limited by ASTM specifications to a maximum of 50%v blending with conventional jet fuel. One reason for the current blend limit is motivation to maintain o-ring swelling consistent with 100% petroleum fuel. This work explores the relationships between o-ring swelling of SAF blend components, model compounds, and various blends in nitrile rubber compared to conventional fuel swelling. Specifically, optical dilatometry measurements were used to gather swell propensity data for 39 different hydrocarbon dopants at 8%v in an iso-alkane solution, 4 dopants at 7 different concentrations, and 19 different fuels or fuel blends. This study also highlights the advantages of using swell measurements, such as those employed here, as a quality control metric instead of the current 8%v aromatics requirement. Notably, the potential is shown to maintain swelling in the conventional fuel range with fuels composed of less than 8%v aromatics

Error Quantification of the Arrhenius Blending Rule for Viscosity of Hydrocarbon Mixtures

13-C-AJFE-UD-26This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as: Boehm RC, Hauck F, Yang Z, Wanstall CT and Heyne JS (2022), Error quantification of the Arrhenius blending rule for viscosity of hydrocarbon mixtures. Front. Energy Res. https://doi.org/10.3389/fenrg.2022.1074699Six hundred and seventy-five measurements of dynamic viscosity and density have been used to assess the prediction error of the Arrhenius blending rule for kinematic viscosity of hydrocarbon mixtures. Major trends within the data show that mixture complexity\u2013binary to hundreds of components\u2014and temperature are more important determinants of prediction error than differences in molecular size or hydrogen saturation between the components of the mixtures

Comparison of the Human Transcriptional Response to Three Hypoxic Environments

DTFAWA-10-C-00080Hypoxia awareness training is a standard facet of military aviator training that is performed to familiarize aviators with the symptoms of hypoxia. The three most common training devices are the hypobaric altitude chamber (AC), the normobaric reduced oxygen breathing device (ROBD), and the normobaric reduced oxygen breathing environment (ROBE). The AC creates hypoxic conditions using reduced atmospheric pressure. The ROBD and ROBE create normobaric hypoxic conditions by supplying a controlled reduced-oxygen gas mixture to trainees who don an aviation-style breathing mask or occupy a sealed chamber, respectively. To determine if differences in the transcriptional response to each of these training devices exist, blood ribonucleic acid (RNA) samples from ten volunteer participants were analyzed by microarray. The resulting gene expression measures were screened for significant changes across time points within and across device runs. Few genes were significant in these comparisons; the most significant differences between timepoints were observed in small nucleolar RNAs and noncoding RNAs, as well as one microRNA and one transfer RNA. The transcriptional response to each training device differs slightly as determined by differences in transcription between time points. However, the role of these transcriptional changes is unclear, as little information exists as to their function or role in the hypoxic response. As all the examined methods induced hypoxic symptoms, and very little difference was observed in gene expression between methods, this limited study did not detect the presence of substantial differences between hypoxia awareness training devices. Future studies using more sensitive sequencing-based gene expression analysis techniques and larger sample sizes may improve the detection of transcriptional differences induced by each training device

Limits of Identification Using VUV Spectroscopy Applied to C8H18 Isomers Isolated by GC 7GC

13-C-AJFE-UD-026This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as: Bell DC, Feldhausen J, Spieles AJ, Boehm RC, Heyne JS. Limits of identification using VUV spectroscopy applied to C8H18 isomers isolated by GC 7GC. Talanta. 2023 Jun 1;258:124451. https://doi.org/10.1016/j.talanta.2023.124451The vacuum ultraviolet detector for gas chromatography can be used to identify structural differences between isomers with similar chromatographic elution times, which adds detail to characterization, valuable for prescreening of sustainable aviation fuel candidates. Although this capability has been introduced elsewhere, vacuum ultraviolet spectroscopy for saturated hydrocarbons has been examined minimally, as the similarities between their spectra are much less significant than their aromatic counterparts. The fidelity with which structural differences can be identified has been unclear. In this work, all possible structural isomers of C8H18 are measured and determined to have unambiguously unique vacuum ultraviolet spectra. Using a statistically based residual comparison approach, the concentration limits at which the spectral differences are interpretable are tested in both a controlled study and a real fuel application. The concentration limit at which the spectral differences between C8H18 isomers are unambiguous is below 0.40% by mass and less than 0.20% with human discretion in our experimental configuration