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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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Drinking water infrastructure in urban settings is increasingly affected by population growth and disruptions like extreme weather events. This study explores how the integration of direct wastewater reuse can help to maintain drinking water service when the system is compromised.
Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.
The kinetics of PL blinking for isolated PbS/CdS nanocrystals changes with the photon excitation energy, with PL blinking increasing in frequency and changing from a two-state to a multistate on/off switching when the excitation energy changes from 1S h –1S e (≈1.4 eV) to 1P h –1P e (≈2.4 eV).
Investigations into bulk heterojunction organic solar cells have demonstrated that molecular mixing within domains and at interfaces significantly impacts device performance. However, these studies often use broad performance metrics that blur fundamental structure–function mechanisms – in particular the role of the mixed phase in charge generation versus charge extraction. In this work, we present a new analysis based on time-delayed collection field that separately quantifies each fundamental step in the charge generation process. Additionally, we present a novel resonant X-ray scattering analysis to quantify the state of the three-phase nanostructure (phase volumes and their compositions) as it exists in the devices. We find that in a model semicrystalline system, decreasing the mixed phase interface between pure donor and pure acceptor domains has little effect on the efficiency of charge transfer (CT) state formation but instead dramatically increases the efficiency of CT state separation. While charge extraction efficiencies are affected as well, this has only a minor impact on device performance. With both structure and properties quantitatively resolved for the first time on the exact same devices, we determine a simultaneous >99% (anti)correlation between (mixed)pure phase volume and charge separation efficiency, with values fitting well to an exponential saturation model. This result plus our ability to eliminate other possible contributing factors provides strong evidence of a causal relationship that reducing interfacial mixed phases to establish a steep energy gradient between pure phases aids in charge generation and extraction in organic solar cells.
Lone-pair covalency can faciliate dynamic tilting of MBr 6 octahedra and increase dynamic structural instabilities.
A new set of equations describing Donnan equilibrium predicts that increased Donnan exclusion in charged polymer networks can occur at high salt concentrations.
The dissociation constants of organic acids decrease (p K a values increase) when they are confined within silica nanopores filled with aqueous solutions. Nanoconfinement stabilizes the protonated species.
This work highlights lignin-derivable, thermoplastic, non-isocyanate polyurethanes as potential alternatives to petroleum-derived analogues with increased toughness and processability due to the functionality of lignin-aromatics (methoxy groups).
X-ray absorption spectroscopy and variable temperature magnetometry show evidence of 4f-orbital mixing in Cp′ 3 Eu, which increases its magnetic susceptibility.
Nickel oxide nanocubes with increased (100) surface facet presence (NiO(100)) were synthesized through a molten salt synthesis procedure to probe their oxygen evolution reaction (OER) activity in order to investigate the relationship between the surface facet and OER performance. While altering the synthesis parameters to decrease NiO(100) particle sizes and agglomeration, a polycrystalline NiO nanoparticle system formed from using Li2O as a Lux-Flood base (labelled Li2O-MSS NiO, where MSS stands for molten salt synthesis). This novel synthesis was further elaborated and the obtained materials were also tested for OER activity. After thorough structural characterization to determine crystallinity, lattice spacings, and elemental distribution, their OER activity was compared versus high surface area NiO(111) nanosheets in a three-electrode rotating disk electrode (RDE) system. The activity trend of (111) > Li2O-MSS > (100) was observed. This decrease in activity of the nanocube and polycrystalline samples was explained by differences between theoretical and experimental conditions, differences in ink rheology and resulting catalyst layer properties, and significant agglomeration seen in the imaging of the sample. Methods for improving the OER activity of these samples are discussed in the conclusion of this study.
A mutation of the axial methionine to leucine unexpectedly lowered the reduction potential of type 1 copper in small laccase, attributable to the presence of water. Two additional mutations removed the water, increasing the potential and activity.
LncRNAs (long non-coding RNAs) are thought to play a significant role in cellular homeostasis during development and disease by interacting with CMPs (chromatin-modifying proteins). We recently showed that following transient focal ischemia, the expression of many lncRNAs was altered significantly in rat brain. We currently analyzed whether focal ischemia also alters the association of lncRNAs with the CMPs Sin3A and coREST (corepressors of the RE-1 silencing transcription factor). RIP (RNA immunoprecipitation) combined with lncRNA microarray analysis showed that 177 of the 2497 lncRNAs expressed in rat cerebral cortex showed significantly increased binding to either Sin3A or coREST following ischemia compared with sham. Of these, 26 lncRNAs enriched with Sin3A and 11 lncRNAs enriched with coREST were also up-regulated in their expressions after ischemia. A majority of the lncRNAs enriched with these CMPs were intergenic in origin. Evaluation of the expression profiles of corresponding protein-coding genes showed that their expression levels correlate with those of the lncRNAs with which they shared a common locus. This is the first study to show that stroke-induced lncRNAs might associate with CMPs to modulate the post-ischemic epigenetic landscape.
The US Virgin Islands, like many other small island nations, face significant challenges related to its energy supply. Their dependency on imported fossil fuels not only drives up energy costs, but also contributes to different environmental problems. Nevertheless, their generally sunny and windy climate makes this archipelago an ideal location for renewable energy development. Increasing the use of sources such as wind, and solar can help reduce their energy dependency, lower their levelized cost of electricity, and improve the health and wellbeing of local communities. In this paper, an optimal dispatcher is employed to analyze the implications on energy security of employing different technology options according to the plans of the local system operator. In this context, short term stability is ensured by inserting operational constraints in the energy management system based on stability analysis developed in PSCAD. The results highlight the usefulness of integrating PV and battery system, while further analysis are required to justify integrating wind power.
During the past few years, due to the growth of electric power consumption, generation costs as well as rises in the level of greenhouse gases efficiency bring special focus on distributed generation. Developing distributed generation resources, especially renewable energy resources, is one of the safest ways to solve such problem. These resources have been decentralised by being installed close to the houses producing few kilowatts. Therefore, there are no losses in transmission lines and provide response for demand. Based on their benefits, the use of such energy resources should be developed in the future, but its management and optimal use is a major challenge. This has become one of the main concerns ofenergy systems researchers. In the current study, an innovative model is provided as a strategic management. It is intended to optimise the operation in smart homes consisting of generation units such as a wind turbine, solar panels, storages, and un/controllable loads. The main objective of this optimisation management is to maximise microgrid profitability for 24 h. The overall results of the model proved that the profit of microgrid increased significantly.
Here, combined antiretroviral therapy (cART) suppress HIV-1 viral replication, such that viral load in plasma remains below the limit of detection in standard assays. However, intermittent episodes of transient viremia (blips) occur in a set of HIV-patients. Given that follicular hyperplasia occurs during lymphoid inflammation as a normal response to infection, it is hypothesised that when the diameter of the lymph node follicle (LNF) increases and crosses a critical size, a viral blip occurs due to cryptic viremia. To study this hypothesis, a theoretical analysis of a mathematical model is performed to find the conditions for virus suppression in all compartments and different scenarios of LNF size changes are simulated. According to the analysis, blips with duration of around 30 days arise when the diameter rise rate is between 0.02 and 0.03 days –1 . Moreover, the final diameter of the site is directly related to the steady states of the virus load after the occurrence of a blip. When the value of R 0 is around 2.1, to have a steady-state below the limit of detection after the viral blip, the maximum final diameters should be greater than 0.7 mm so that there is a relative loss of connection between compartments.
The Pohang Light Source (PLS) storage ring is a synchrotron light source with the emittance of 18.9 nm at 2.5 GeV and has delivered vacuum ultraviolet and soft x-rays during the past 15 years. We investigate a lattice design for the 3 GeV ring for an upgrade project that keeps the existing tunnel. We investigate a double bend achromat (DBA) structure that provides the reduction of emittance by a factor of 3 and the increase of the number of straight section by a factor of 2 than the existing PLS lattice. We present several characteristics on the beam dynamics, dynamic aperture, and optics matching in the low-emittance lattice which includes squeezed space between magnets. Present PLS lattice has 12 long straight sections of 6.8 m long and the lattice is modified to provide the additional 12 short straight sections of 3.7 m long by eliminating a bending magnet in the middle of the cell of the present triplet bending achromat lattice. Thus, the new lattice consists of a total of 24 straight sections that consist of 12x6.8 and 12x3.7 m long straight sections, which can provide the spaces for the 4- and 2-m-long insertion devices. We present the design results in detail for a DBA lattice in 281.82 m long circumference. It is shown that the emittance of 6.2 nm in the lattice can be achieved by allowing nonzero dispersions in the straight sections. The lattice provides high brilliance at the photon energy of a few 10 keV that meets the requirements by synchrotron radiation users; however, it may require a strong focusing and become sensitive to machine errors and effects of insertion devices. Thus, we investigated the dynamic aperture in the lattice by a simulation method and achieved an optimal tune under the strength of sextupole magnets of 500 T/m{sup 2} for the low-emittance ring. We also performed the lattice tunings to restore the optics due to the errors in the low-emittance ring. In result, our designed lattice shows a good optimization in terms of emittance, brilliance, and circumference as a light source for a 3 GeV.
The electron field emission (EFE) properties of microcrystalline diamond (MCD) films are significantly enhanced due to the Fe coating and post-annealing processes. The 900 Degree-Sign C post-annealed Fe coated diamond films exhibit the best EFE properties, with a turn on field (E{sub 0}) of 3.42 V/{mu}m and attain EFE current density (J{sub e}) of 170 {mu}A/cm{sup 2} at 7.5 V/{mu}m. Scanning tunnelling spectroscopy (STS) in current imaging tunnelling spectroscopy mode clearly shows the increased number density of emission sites in Fe-coated and post-annealed MCD films than the as-prepared ones. Emission is seen from the boundaries of the Fe (or Fe{sub 3}C) nanoparticles formed during the annealing process. In STS measurement, the normalized conductance (dI/dV/I/V) versus V curves indicate nearly metallic band gap, at the boundaries of Fe (or Fe{sub 3}C) nanoparticles. Microstructural analysis indicates that the mechanism for improved EFE properties is due to the formation of nanographite that surrounds the Fe (or Fe{sub 3}C) nanoparticles.
Single Nitrogen-Vacancy (NV) centers in diamond close to the crystal surface are very promising magnetic field sensors with very high sensitivity. Here, we report the enhanced creation of very shallow (less than 3 nm below the diamond surface) NV centers by using fluorine and oxygen plasma treatment. We observe a four fold increase—from 0.11% to about 0.45% in the production yield when the sample surface is terminated with fluorine or oxygen atoms. This effect is explained by the stabilization of the NV's negative charge state which is influenced by the various defects present on the diamond surface.