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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.

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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Tree growth, transpiration, and water-use efficiency between shoreline and upland red maple (Acer rubrum) trees in a coastal forest

Coastal shoreline forests are vulnerable to seawater exposure, the impacts of which will increase due to sea-level rise, but the longterm adaption strategies and vulnerability of coastal forests are not well understood. We used whole-tree transpiration, leaf water potential, tree-ring width, and tree-ring d13C (a proxy for intrinsic water use efficiency, iWUE) to examine the long-term adaption strategies of red maple (Acer rubrum) trees at the coastal interface (i.e., shoreline) and nearby upland in Maryland, USA. Red maple trees that grew along the shoreline and were exposed to slightly saline water (up to two PSU) had higher transpiration rates than those growing in the nearby upland forest during a wet year, but these differences disappeared during a normal precipitation year. Shoreline trees grew more slowly than upland trees over the last four decades, but these growth differences have disappeared in the last six years. Shoreline and upland trees had similar variation in iWUE, indicating that higher transpiration rates of the seawater exposed trees did not translate into differences in water use efficiency. There were no differences in predawn and midday water potential between upland and shoreline trees, suggesting no water stress occurs in shoreline trees. These findings indicate that urrent soil salinity is below the threshold to constrain coastal red maple physiological activities.

Wang, Wenzhi↗
DOE OSTI2018

Sono-photodynamic modality for cancer treatment using bio-degradable bio-conjugated sonnelux nanocomposite in tumor-bearing mice: Activated cancer therapy using light and ultrasound

Highlights: • An up-to-date cancer therapy: Sono-photodynamic therapy (SPDT) in combination with sonnelux (SLux) as a sono-photosensitizer loaded on folic acid conjugated nanographene oxide nanoparticles (FA-NGO- SLux). • A novel nanomaterial with great potential as effective drug delivery system in targeting sono-photo-dynamic-therapy (SPDT). The underlying work was conducted aiming at cancer targeted therapy using the sono-photodynamic therapy (SPDT) in combination with sonnelux (SLux) as a sono-photosensitizer loaded on folic acid conjugated nanographene oxide nanoparticles (FA-NGO-SLux) as an up-to-date treating cancer modality. Study was conducted on A total of 130 male Swiss albino mice with age 60–65 day, weighing 20 ± 25 g, inoculated with Ehrlich ascites carcinoma (EAC) subdivided into 13 group. Two sources of energy were used; namely infrared laser and Ultrasound (pulsed and continuous wave mode). Results revealed that Nano-SLux is a potential photosensitizer and sonosensitizer for photodynamic or sonodynamic treatment of Ehrlich ascites tumor tissue. Nano-SLux can play important roles in inhibiting tumor growth and even inducing cell death, which might be attributed to Photo and/or sono-chemical activation mechanism. Infra-red laser in combination with ultrasound in the presence of Nano- SLux has a potential antitumor effect. Sonocation followed by light photon irradiation proves its excellent efficiency as an anticancer therapy. The results suggest that folic acid-conjugated nano-graphene oxide loaded with sono-photo-sensitizers (FA–NGO–SPSs) could be used as a novel nanomaterial with great potential as effective drug delivery system in targeting sono-photo-dynamic-therapy (SPDT).

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Microstructural analysis of recycled concrete using X-ray microtomography

This paper reports an investigation of the recycled concrete (RC) microstructure using synchrotron microtomography (μCT) at the Advanced Light Source combined with Scanning Electron Microscopy analysis. The study evaluated the influence of 50% of recycled concrete aggregate (RCA) and its water absorption compensation on the RC microstructure. The following variables were studied: a) the compressive strength of the original concrete used to obtain the RCA (40 and 80 MPa) and b) the initial moisture condition of the RCA (Saturated Surface Dry and Oven Dry). The microtomographic images showed the mixtures cast with RCA in the dry condition developed an evident macropore network surrounding the RCA particle that was not observed in the mixtures using RCA in the SSD condition. SEM images confirmed the initial findings from μCT and showed that the thickness of the interfacial transition zone in RC is in the same order of magnitude as the reference concrete.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Surface Pb nanoparticle aggregation, coalescence and differential capacitance in a deep eutectic solvent using a simultaneous sample-rotated small angle x-ray scattering and electrochemical methods approach [Surface Pb nanoparticle aggregation, coalescence and differential capacitance in a deep eutectic solvent using a simultaneous grazing transmission small angle x-ray scattering and electrochemical methods approach]

Nanoparticle electrodeposition is a simple and scalable approach to synthesizing supported nanoparticles. Used with a deep eutectic solvent (DES), surface nanoparticles can be assembled and exhibit unique surface charge separation when the DES is adsorbed on the nanoparticle surface. Key to understanding and controlling the assembly and the capacitance is a thorough understanding of surface particle mobility and charge screening, which requires an in-situ approach. In this study, Pb particle formation, size, shape and capacitance are resolved in a 1:2 choline Cl – : urea deep eutectic solvent whilst sweeping the cell potential in the range: 0.2 V to –1.2 V (vs. Ag/AgCl). These system parameters were resolved using a complementary suite of sample-rotated small angle X-ray scattering (SR-SAXS) and electrochemical impedance spectroscopy (EIS), which are presented and discussed in detail. This approach is able to show that both particle and ion transport are impeded in the DES, as aggregation occurs over the course of 6 minutes, and dissolved Pb ions accumulate and remain near the surface after a nucleation pulse is applied. The DES-Pb interactions strongly depend on the cell potential as evidenced by the specific differential capacitance of the Pb deposit, which has a maximum value of 2.5 +/– 0.5 F g –1 at –1.0 V vs. Ag/AgCl. Together, the SR-SAXS-EIS approach is able to characterize the unique nanoparticle capacitance, mobility and ion mobility in a DES and can be used to study a wide range of nanoparticle deposition systems in-situ .

36 MATERIALS SCIENCE↗
DOE OSTI2023

Optimizing Phase Change Composite Thermal Energy Storage Using the Thermal Ragone Framework

The thermal Ragone framework can be applied to the design of thermal energy storage heat exchangers to identifying relationships between their power requirements and energy capabilities. This presentation focuses on the design of planar thermal energy storage heat exchangers with phase change materials and thermal conductivity additives. Finite-difference models were used to optimize thermal storage heat exchanger designs focusing on key design parameters of conductivity additive volume fraction, spacing between tubes, and the phase transition temperatures. Design trends were developed for optimal designs based on varying thermal power requirements. To aid in future device design, models of reduced complexity were developed with the ability to predict optimal designs with computational speeds up to 5,000 times faster than finite-difference models.

ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION,↗
DOE OSTI2017

Determination of origin and intended use of plutonium metal using nuclear forensic techniques

Nuclear forensics techniques, including micro-XRF, gamma spectrometry, trace elemental analysis and isotopic/chronometric characterization were used to interrogate two, potentially related plutonium metal foils. These samples were submitted for analysis with only limited production information, and a comprehensive suite of forensic analyses were performed. Resulting analytical data was paired with available reactor model and historical information to provide insight into the materials’ properties, origins, and likely intended uses. Both were super-grade plutonium, containing less than 3% 240 Pu, and age-dating suggested that most recent chemical purification occurred in 1948 and 1955 for the respective metals. Additional consideration of reactor modelling feedback and trace elemental observables indicate plausible U.S. reactor origin associated with the Hanford site production efforts. In conclusion, based on this investigation, the most likely intended use for these plutonium foils was 239 Pu fission foil targets for physics experiments, such as cross-section measurements, etc.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗