Microstructural characterization of a thin film ZrN diffusion barrier in an As-fabricated U–7Mo/Al matrix dispersion fuel plate
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Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others.
A strategy for creating nanostructured films is the alignment of nanoparticles into ordered superstructures as living organisms synthesize biomaterials with superior physical properties using nanoparticle building blocks. We synthesized nanostructured films of Cu{sub 2}O of variable grain size by establishing the condition of supersaturation for creation of nanoparticles of copper which deposited as nanograined films and which was then oxidized. This technique has the advantage of being compatible with conventional vacuum processes for electronic device fabrication. The Cu{sub 2}O film samples consisted of a secondary structure of spherical particles of almost uniform size, each particle being an agglomerate of primary nanocrystals. Fractal analysis of the AFM images of the samples is carried out for studying the aggregation mechanism. Grain size tuning of the nanostructured Cu{sub 2}O films has been studied using XRD, and micro-Raman and photoluminescence spectroscopy.
Measurements are conducted to identify the motion of tungsten and helium atoms during the formation of tungsten fuzz. In a first series of experiments the mobility of helium within the growing fuzz was measured by adding 3 He to the different stages of plasma exposure under conditions that promoted tungsten fuzz growth. Ion beam analysis was used to quantify the amount of 3 He remaining in the samples following the plasma exposure. The results indicate that the retention of helium in bubbles within tungsten is a dynamic process with direct implantation rather than diffusion into the bubbles, best describing the motion of the helium atoms. In the second experiment, an isotopically enriched layer of tungsten (~92.99% 182 W) is deposited on the surface of a bulk tungsten sample with the natural abundance of the isotopes. This sample is then exposed to helium plasma at the conditions necessary to support the formation of tungsten 'fuzz'. Depth profiles of the concentration of each of the tungsten isotopes are obtained using secondary ion mass spectrometry (SIMS) before and after the plasma exposure. The depth profiles clearly show mixing of tungsten atoms from the bulk sample toward the surface of the fuzz. Lastly, this supports a physical picture of the dynamic behavior of helium bubbles which, also, causes an enhanced mixing of tungsten atoms.
With the data samples taken at center-of-mass energies from 2.00 to 3.08 GeV with the BESIII detector at the BEPCII collider, a partial wave analysis on the e + e − → π + π − π 0 process is performed. The Born cross sections for e + e − → π + π − π 0 and its intermediate processes e + e − → ρ π and ρ ( 1450 ) π are measured as functions of s . The results for e + e − → π + π − π 0 are consistent with previous results measured with the initial state radiation method within one standard deviation, and improve the uncertainty by a factor of ten. By fitting the line shapes of the Born cross sections for the e + e − → ρ π and e + e − → ρ ( 1450 ) π , a structure with mass M = 2119 ± 11 ± 15 MeV / c 2 and width Γ = 69 ± 30 ± 5 MeV is observed with a significance of 5.9 σ , where the first uncertainties are statistical and the second ones are systematic. This structure can be interpreted as an excited ω state. Published by the American Physical Society 2024
Mass spectrometry imaging (MSI) is a transformative imaging method that supports the untargeted, quantitative measurement of the chemical composition and spatial heterogeneity of complex samples with broad applications in life sciences, bioenergy, and health. While MSI data can be routinely collected, its broad application is currently limited by the lack of easily accessible analysis methods that can process data of the size, volume, diversity, and complexity generated by MSI experiments. The development and application of cutting-edge analytical methods is a core driver in MSI research for new scientific discoveries, medical diagnostics, and commercial-innovation. However, the lack of means to share, apply, and reproduce analyses hinders the broad application, validation, and use of novel MSI analysis methods. To address this central challenge, we introduce the Berkeley Analysis and Storage Toolkit (BASTet), a novel framework for shareable and reproducible data analysis that supports standardized data and analysis interfaces, integrated data storage, data provenance, workflow management, and a broad set of integrated tools. Based on BASTet, we describe the extension of the OpenMSI mass spectrometry imaging science gateway to enable web-based sharing, reuse, analysis, and visualization of data analyses and derived data products. Here, we demonstrate the application of BASTet and OpenMSI in practice to identify and compare characteristic substructures in the mouse brain based on their chemical composition measured via MSI.
There is a need for real-time process monitoring and person-portable in-field tools for the determination of the hydrogen /deuterium ratio (H/D) in heavy water production facilities. Current methods for H/D determination require periodic sampling and analysis. This approach does not provide the opportunity for continuous monitoring and verification by the IAEA and is relatively expensive, error prone and inefficient.
Washington River Protection Solutions, LLC (WRPS) contracted Pacific Northwest National Laboratory (PNNL) in support of their maturation testing and analysis to develop and deploy an ambient temperature solidification/stabilization process for low-activity waste (LAW) (referred to as “grout” in this report). The intent of this effort is to support a sample-and-send regulatory and processing strategy in the Hanford 200 West Area, specifically considering grout waste forms disposal at Hanford in the Integrated Disposal Facility (IDF). Currently the disposal of grouted LAW is not an option because the IDF is not permitted to receive this waste form. The material presented in this report is intended to help inform the U.S. Department of Energy (DOE), the site operating contractors, regulatory agencies, and stakeholders of the future implications of IDF disposal of a grouted LAW waste form, specifically for the behavior of nitrate (NO 3 - ) and nitrite (NO 2 - ) at the Hanford. The only calculation of nitrate release from a hypothetical grouted LAW inventory in the IDF showed that the overall release was slightly above the compliance limit of 45 mg/L nitrate and 3.32 mg/L nitrate after 1000 years (Asmussen et al. 2019). As such, uncertainty around the impact of nitrate and nitrite release from the IDF was identified in the recent National Academies of Sciences study of Hanford supplemental LAW by both the national laboratory team and Hanford stakeholders (Bates et al. 2023). However, these calculations (and others for the IDF involving secondary waste grout) may be conservative as no nitrate and nitrite retention in the grout waste form was assumed, nor any attenuation in the subsurface. There is evidence from the literature of processes that can attenuate nitrate migration both in the waste form and in the Hanford subsurface. If found to be technically defensible and likely to occur in the IDF and associated subsurface, then these processes should be included in modeling of the IDF to represent the behavior of nitrate and nitrite more accurately. Doing so would remove unnecessary conservatism in the modeling projections and reduce the uncertainty in assessments of facility compliance of a grouted LAW waste form in the IDF.
The purpose of this experiment was to evaluate how circadian clock regulation impacts carbon partitioning between storage, growth, and product synthesis in Synechococcus elongatus PCC 7942 in providing insights to strategies for enhanced bioproduction. Culture samples were collected at 0, 0.5, 1, 2, 4, 6, and 8 hours for extracellular sucrose analysis. Circadian metabolomics data was acquired using a Agilent single quadrupole gas chromatography-mass spectrometer and processed using Agilent Mass Hunter for targeted sucrose quantification. Metabolomic analysis of PCC 7942 light-dark cycle cultures transitioned to constant light revealed distinct temporal patterns in sucrose production. Processed metabolomic datasets are openly accessible from the PNNL DataHub project dataset download page and contain secondary processed GC-MS results files and supporting metadata materials linked to relevant source code information supporting data transparency and reuse.
The detailed mechanisms of the sealing of a single fracture, from hydration to almost complete closure by increase of confining pressure, as monitored from in situ synchrotron X-ray microtomography during the flow of carbonated water, is here shown for the first time. Different mechanisms play the key role at different stages in the evolution of the fracture. Hydration mechanically weakens the surfaces of the fracture and induces a first closure due to microcracking at the asperity contacts, increasing their size and creating choke points. Increase in confining stress promptly hydraulically seals the fracture by closing the main choke point, with a relative small deformation of the sample. Finally, the more pervasive mechanical deformation observed at higher stresses almost completely seals the whole fracture. The evolution of the sample has been described and quantified using 4D image processing, focusing on the evolution of aperture and digital volume correlation. Hydraulic properties of the sample at different stages have been modeled via Stokes flow simulation, and the results compared to the morphometric analysis, finding positive correlations with the average fracture aperture variation along the flowpath in function of confining pressure. Opalinus Clay is found to be a rock markedly prone to sealing in case of flow with carbonated water; this behavior is the result of the large fraction of clays and of its microstructure, lacking both cementing phases and large stiff particles. CO2 in this sample has no evident role in the evolution of the fracture; chemically induced weathering on the surface has not been detected, in contrast with the behavior observed in samples with carbonates as cementing phase.
Genomics has transformed our understanding of the genetic architecture of traits and the genetic variation present in plants. Here, we present a review of how RNA-seq can be performed to tackle research challenges addressed by plant sciences. We discuss the importance of experimental design in RNA-seq, including considerations for sampling and replication, to avoid pitfalls and wasted resources. Approaches for processing RNA-seq data include quality control and counting features, and we describe common approaches and variations. Though differential gene expression analysis is the most common analysis of RNA-seq data, we review multiple methods for assessing gene expression, including detecting allele-specific gene expression and building co-expression networks. With the production of more RNA-seq data, strategies for integrating these data into genetic mapping pipelines is of increased interest. Finally, special considerations for RNA-seq analysis and interpretation in plants are needed, due to the high genome complexity common across plants. By incorporating informed decisions throughout an RNA-seq experiment, we can increase the knowledge gained.
To represent the loads spectra of general aviation aircraft operating in the Continental United States, VG and VGH data collected since 1963 in eight operational categories were processed and analyzed. Adequacy of data sample and current operational categories, and parameter distributions required for valid data extrapolation were studied along with envelopes of equal probability of exceeding the normal load factor (n sub z) versus airspeed for gust and maneuver loads and the probability of exceeding current design maneuver, gust, and landing impact n sub z limits. The significant findings are included.
The Microgravity and Materials Processing Facility (MMPF) of the Space Station is examined. The MMPF is designed to accommodate individual experiments and associated hardware and is to be housed in the Manufacturing and Technology Laboratory Module. The objectives of the microgravity and materials processing study and the user, experiment/equipment, MMPF system requirements, and programmatics and planning development tasks of the study are described. Consideration is given to the acceleration environment, on-orbit sample preparation and analysis, mission-time-line analyses, and payload complement trades. Diagrams of the MMPF are presented.
A study of differences between the morning and evening monthly rainfall for 5 x 5 deg cells over the oceans from the SSM/I data has been conducted. The monthly rainfalls are estimated from the technique given by Wilheit et al. The difference between the morning and evening monthly rainfall arises due to the various random errors involved in the retrieval process, the sampling error in the observations, and the diurnal component of oceanic rainfall. The diurnal component is weak but clearly visible when averaged over large areas and for long time periods. The analysis shows that morning rainfall is consistently greater than evening rainfall. The Northern Hemisphere seem to have a larger diurnal variation than does the Southern Hemisphere. The maximum ratio between the morning and evening monthly rainfall is 1.7 while 1.2 is the more typical value.
At least two questions arise in developing a life-detection strategy: What do we look for and what will positive detection tell us? Unfortunately, many 'biomarkers' are not conclusive markers of biology. For example, sugars, amino acids, polycyclic aromatic hydrocarbons (PAH) and certain bacteria-like morphologies can all be produced non-biologically. Inferences of life following the detection of several inconclusive biomarkers in one sample will always be questioned. Although DNA, RNA and proteins are excellent markers of biology, and preserved on Earth for several millions of years, their survival over longer periods of time is low. Ideally, we should target biomarkers which are both stable over time and formed exclusively from biological processes, i.e. a 'category 1' biomarker under the new classification system of Mckay. We have used antibodies to detect category 1 and other biomarkers in rock samples. Extraction takes a few minutes and analysis a few hours. We have presented use of new antibodies to detect hopanes and have shown proof of operation during martian gravity.
The International Space Station Materials and Processes (ISS M&P) team has multiple material samples on MISSE 6, 7 and 8 to observe Low Earth Orbit (LEO) environmental effects on Space Station materials. Optical properties, thickness/mass loss, surface elemental analysis, visual and microscopic analysis for surface change are some of the techniques employed in this investigation. The ISS M&P team has participated in previous MISSE activities in order to better characterize the LEO effects on Space Station materials. This investigation will further this effort. Results for the following MISSE 6 samples materials will be presented: a comparison of anodize and chemical conversion coatings on various aluminum alloys, electroless nickel; AZ93 white ceramic thermal control coating with and without Teflon; Hyzod(TM) polycarbonate used to temporarily protect ISS windows; Russian quartz window material; reformulated Teflon (TM) coated Beta Cloth (Teflon TM without perfluorooctanoic acid (PFOA)) and a Dutch version of beta cloth. Discussion for current and future MISSE materials experiments will be presented. MISSE 7 samples are: deionized water sealed anodized aluminum Photofoil(TM); indium tin oxide (ITO)- coated Kapton(TM) used as thermo-optical surfaces; mechanically scribed tin-plated beryllium-copper samples for "tin pest" growth ( alpha/Beta transformation); Crew Exploration Vehicle (CEV) parachute soft goods. MISSE 8 sample: exposed "scrim cloth" (fiberglass weave) from the ISS solar array wing material, Davlyn fiberglass sleeve material, Permacel and Intertape protective tapes, and ITO-coated Kapton.
The Mars Science Laboratory (MSL) Rover, Curiosity spent approx 150 sols at Yellowknife Bay (YKB) studying a section of fluvio-lacustrine sedimentary rocks (with potential indications of volcanic influence), informally known as the Yellowknife Bay formation. YKB lies in a distal region of the Peace Vallis alluvial fan, which extends from the northern rim of Gale Crater toward the dune field at the base of Mt Sharp. Sedimentological and stratigraphic observations are consistent with the Yellowknife Bay formation being part of a distal fan deposit, which could be as young as middle Hesperian to even early Amazonian in age (approx 3.5 to 2.5 Ga). The Yellowknife Bay formation hosts a unit of mudstone called the Sheepbed member. Curiosity obtained powdered rock samples from two drill holes in the Sheepbed Member, named John Klein and Cumberland, and delivered them to instruments in Curiosity. Data from CheMin, a combined X-ray diffraction (XRD)/X-ray fluorescence instrument (XRF), has allowed detailed mineralogical analysis of mudstone powders revealing a clay mineral component of approx 20 wt.% in each sample. The clay minerals are important indicators of paleoenvironmental conditions and sensitive recorders of post-depositional alteration processes. The XRD pattern of John Klein reveals a 021 band consistent with a trioctahedral phyllosilicate. A broad peak at approx 10A with a slight inflexion at approx 12A indicates the presence of 2:1 type clay minerals in the John Klein sample. The trioctahedral nature of the clay minerals, breadth of the basal reflection, and presence of a minor component with larger basal spacing suggests that John Klein contains a trioctahedral smectite (probably saponite), whose interlayer is largely collapsed because of the low-humidity conditions. The XRD patterns show no evidence of corrensite (mixed-layer chlorite/smectite) or chlorite, which are typical diagenetic products of trioctahedral smectites when subjected to burial and heating >60degC in the presence of water. Given estimated geothermal gradients on Mars temperatures <60 degC might still be consistent with (but do not require) moderate burial. However, our ability to identify interstratified minerals is greatly limited by the lack of access to traditional treatments methods used in the lab (e.g., ethylene glycol solvation). Our preferred explanation for the origin of trioctahedral smectites in Sheepbed mudstone is in situ production via reaction of olivine, water and Si-bearing amorphous material, an important mudstone component detected by XRD. Elevated levels of magnetite in the Sheepbed and the trioctahedral monomineralic nature of the clay minerals support this model. These observations, combined with previous studies of olivine stability, support the persistence of circum-neutral hydrous conditions for thousands of years at YKB.
The Mars Science Laboratory (MSL) Rover, Curiosity spent approx 150 sols at Yellowknife Bay (YKB) studying a section of fluvio-lacustrine sedimentary rocks (with potential indications of volcanic influence), informally known as the Yellowknife Bay formation. YKB lies in a distal region of the Peace Vallis alluvial fan, which extends from the northern rim of Gale Crater toward the dune field at the base of Mt Sharp. Sedimentological and stratigraphic observations are consistent with the Yellowknife Bay formation being part of a distal fan deposit, which could be as young as middle Hesperian to even early Amazonian in age (approx. 3.5 to 2.5 Ga). The Yellowknife Bay formation hosts a unit of mudstone called the Sheepbed member. Curiosity obtained powdered rock samples from two drill holes in the Sheepbed Member, named John Klein and Cumberland, and delivered them to instruments in Curiosity. Data from CheMin, a combined X-ray diffraction (XRD)/X-ray fluorescence instrument (XRF), has allowed detailed mineralogical analysis of mudstone powders revealing a clay mineral component of approx. 20 wt.% in each sample. The clay minerals are important indicators of paleoenvironmental conditions and sensitive recorders of post-depositional alteration processes. The XRD pattern of John Klein reveals a 02l band consistent with a trioctahedral phyllosilicate. A broad peak at approx. 10A with a slight inflexion at approx. 12A indicates the presence of 2:1 type clay minerals in the John Klein sample. The trioctahedral nature of the clay minerals, breadth of the basal reflection, and presence of a minor component with larger basal spacing suggests that John Klein contains a trioctahedral smectite (probably saponite), whose interlayer is largely collapsed because of the low-humidity conditions. The XRD patterns show no evidence of corrensite (mixed-layer chlorite/smectite) or chlorite, which are typical diagenetic products of trioctahedral smectites when subjected to burial and heating >60 C in the presence of water. Given estimated geothermal gradients on Mars temperatures <60 C might still be consistent with (but do not require) moderate burial. However, our ability to identify interstratified minerals is greatly limited by the lack of access to traditional treatments methods used in the lab (e.g., ethylene glycol solvation). Our preferred explanation for the origin of trioctahedral smectites in Sheepbed mudstone is in situ production via reaction of olivine, water and Si-bearing amorphous material, an important mudstone component detected by XRD. Elevated levels of magnetite in the Sheepbed and the trioctahedral monomineralic nature of the clay minerals support this model. These observations, combined with previous studies of olivine stability, support the persistence of circum-neutral hydrous conditions for thousands of years at YKB.