A Comparative XAFS Study of Gold-thiolate Nanoparticles and Nanoclusters
Abstract not provided
Chevrier, D. M.↗
SEARCH · Engineering Papers
Results for “Comparative Study”
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Exploring Secondary Markets to Improve Circularity: A Comparative Case Study of Photovoltaics and Hard-Disk Drives
Each year renewable energy generation increases notably with solar panel installations, but these panels have a limited lifespan and will produce between 2 and 4 million metric tons of waste by 2040. Similarly, there are currently between 20 to 70 million hard-disk drives (HDDs) reaching end-of-life (EOL) annually. The circular economy (CE) strives to recycle and reuse materials that are rare and expensive to obtain, minimizing waste. However, studying the potential circularity of photovoltaics (PV) and HDDs requires various data, for instance, on the maturity of the secondhand markets. In this context, the objective of the present study is to identify the current state of secondhand PV and HDD markets. After conducting a literature review, an automated data collection process was set up for that purpose. The analysis of the literature and collected data assess the maturity of the secondhand PV modules and HDDs markets and highlight differences between them.
agent-based modelling↗
Vortex motion induced losses in tantalum resonators
Tantalum (Ta)-based superconducting circuits have been demonstrated to enable ultrahigh qubit quality factors (𝑄), motivating a careful study of the microscopic origin of the remaining losses that limit their performance. We have recently shown that the losses in Ta-based resonators are dominated by two-level systems at low microwave powers and millikelvin temperatures. We also observe that some devices exhibit loss that is exponentially activated at a lower temperature inconsistent with the superconducting critical temperature (T 𝑐 ) of the constituent film. Specifically, dc resistivity measurements show a T 𝑐 of over 4 K, while microwave measurements of resonators fabricated from these films show losses that increase exponentially with temperature with an activation energy as low as 0.3 K. Here, in this study, we present a comparative study of the structural and thermodynamic properties of Ta-based resonators and identify vortex motion-induced loss as the source of thermally activated microwave loss. Through careful magnetoresistance and x-ray diffraction measurements, we observe that the increased loss occurs for films that are in the clean limit, where the superconducting coherence length (𝜉) is shorter than the mean free path (𝑙). Vortex motion-induced losses are suppressed for films in the dirty limit, which show evidence of structural defects that can pin vortices. We verify this hypothesis by explicitly pinning vortices via patterning, and we find that we can suppress the loss by microfabrication.
36 MATERIALS SCIENCE↗
Comparative model study of two-photon deterministic passive quantum logical gates
We use the 'modes of the universe' approach to study a cavity-mediated two-photon logical gate recently proposed by Koshino, Ishizaka, and Nakamura. We clarify the relationship between the more commonly used input-output formalism and that of Koshino et al. and show that some elements of this gate had been anticipated by other authors. We conclude that their proposed gate can work both in the good and bad cavity limits, provided only that the pulses are long enough. Our formalism allows us to estimate analytically the size of the various error terms and to follow the spectral evolution of the field+cavity system in the course of the interaction.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Comparative imaging study in ultrasound, MRI, CT, and DSA using a multimodality renal artery phantom
Purpose: A range of anatomically realistic multimodality renal artery phantoms consisting of vessels with varying degrees of stenosis was developed and evaluated using four imaging techniques currently used to detect renal artery stenosis (RAS). The spatial resolution required to visualize vascular geometry and the velocity detection performance required to adequately characterize blood flow in patients suffering from RAS are currently ill-defined, with the result that no one imaging modality has emerged as a gold standard technique for screening for this disease. Methods: The phantoms, which contained a range of stenosis values (0%, 30%, 50%, 70%, and 85%), were designed for use with ultrasound, magnetic resonance imaging, x-ray computed tomography, and x-ray digital subtraction angiography. The construction materials used were optimized with respect to their ultrasonic speed of sound and attenuation coefficient, MR relaxometry (T{sub 1},T{sub 2}) properties, and Hounsfield number/x-ray attenuation coefficient, with a design capable of tolerating high-pressure pulsatile flow. Fiducial targets, incorporated into the phantoms to allow for registration of images among modalities, were chosen to minimize geometric distortions. Results: High quality distortion-free images of the phantoms with good contrast between vessel lumen, fiducial markers, and background tissue to visualize all stenoses were obtained with each modality. Quantitative assessments of the grade of stenosis revealed significant discrepancies between modalities, with each underestimating the stenosis severity for the higher-stenosed phantoms (70% and 85%) by up to 14%, with the greatest discrepancy attributable to DSA. Conclusions: The design and construction of a range of anatomically realistic renal artery phantoms containing varying degrees of stenosis is described. Images obtained using the main four diagnostic techniques used to detect RAS were free from artifacts and exhibited adequate contrast to allow for quantitative measurements of the degree of stenosis in each phantom. Such multimodality phantoms may prove useful in evaluating current and emerging US, MRI, CT, and DSA technology.
60 APPLIED LIFE SCIENCES↗
Comparative Policy Study for Green Buildings in U.S. and China
Prominent barriers facing the U.S. green building industry include the fact that government bodies that supervise health, fire safety, land, and other public operations are slow to revise codes to accommodate green building (regulatory barrier). In China, the lack of a green building professional accreditation process similar to the Leadership in Energy and Environmental Design (LEED) AP process limits the green building workforce capacity development (informational barrier). The main policies highlighted in this report to tackle these barriers are 1) comprehensive codes and labeling plan (informational, institutional), 2) government-led targets and demonstrations (risk), 3) education and awareness programs (informational), 4) fiscal policy that supports green building investment (financial), and 5) integrated design promotion (institutional, financial).
29 ENERGY PLANNING, POLICY, AND ECONOMY↗
Progress on Fabrication of Planar Diffusion Couples with Representative TRISO PyC/SiC Microstructure
Release of fission products from tristructural-isotropic (TRISO) coated particle fuel limits the fuel’s operational lifetime and creates potential safety and maintenance concerns. A need for diffusion analysis in representative TRISO layers exists to provide fuel performance models with high fidelity data to improve fuel performance and efficiency. An effort has been initiated to better understand fission product transport in, and release from, quality TRISO fuel by investigating diffusion couples with representative pyrocarbon (PyC) and silicon carbide (SiC). Here planar PyC/SiC diffusion couples are being developed with representative PyC/SiC layers using a fluidized bed chemical vapor deposition (FBCVD) system identical to those used to produce laboratory-scale TRISO fuel for the Advanced Gas Reactor Fuel Qualification and Development Program’s (AGR) first fuel irradiation. The diffusivity of silver, the silver and palladium system, europium, and strontium in the PyC/SiC will be studied at elevated temperatures and under high temperature neutron irradiation. The study also includes a comparative study of PyC/SiC diffusion couples with varying TRISO layer properties to understand the influence of SiC microstructure (grain size) and the PyC/SiC interface on fission product transport. The first step in accomplishing these goals is the development of the planar diffusion couples. The diffusion couple construction consists of multiple steps which includes fabrication of the primary PyC/SiC structures with targeted layer properties, introduction of fission product species and seal coating to create an isolated system. Coating development has shown planar PyC/SiC diffusion couples with similar properties to AGR TRISO fuel can be produced. A summary of the coating development process, characterization methods, and status are presented.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
PathTrace and MPVEASI: A Path Analysis Comparative Validation Study
Developed in 2018, PathTrace is a software package built with the intention of making path analysis simple and intuitive. PathTrace is a top-down pathway analysis software where a user is able to explore vulnerable pathways into a facility. The intention of utilizing a software tool like PathTrace is to characterize an existing physical protection system (PPS) and to upgrade the system to achieve a high level of response interruption, or probability of interruption (P I ) of the adversary. There are four steps for conducting path analysis using PathTrace. The first step is to identify an image to use to build the model and scale the model within PathTrace using a section of known distance (wall or fence perimeter, for example). The scaling process will produce a grid of cells through which the user is able to build a model. The second step is to fill out the grid of cells with four categories of materials: Barriers, Detection Areas, Jumps, and Targets. These materials apply associated delay and detection values to the cells in which they are applied. The third step is to represent the adversary and response forces. The adversaries are represented by their capabilities in interacting with the materials identified in step two, and the response is represented by how quickly they will be able to respond to an adversary attack. Finally, the user is able to take all of the information from the previous three steps and perform a Most Vulnerable Path (MVP) analysis. In this stage, the user is able to visualize vulnerable adversary pathways and reason about how to upgrade these pathways to provide a high level of P I .
97 MATHEMATICS AND COMPUTING↗
Comparative surface studies of oxygen passivated FeCo nanoparticles and this films
N/A
36 MATERIALS SCIENCE↗
Comparative Computational Study of Solid-solid Interface in Liquid- and Solid-electrolyte Based Batteries.
Abstract not provided.
Leung, Kevin↗
Comparative Reliability Study on Thermal Energy Storage Systems for Integrated Energy Systems
Explore the source record for details and available documents.
Sabatino, Samantha↗
History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies
Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Efficacy and Safety of Two Different n-Butyl-2-Cyanoacrylates for the Embolization of Varicoceles: A Prospective, Randomized, Blinded Study
Purpose: This was a prospective, randomized, blinded comparative study of the efficacy and safety of two different n-butyl-2-cyanoacrylates (NBCAs) for embolization of varicoceles. Methods: A total of 112 insufficient spermatic veins (left-sided, n = 84; right-sided, n = 28) that were diagnosed in 83 adult males were prospectively randomized for blinded embolization with NBCA (n = 54; Histoacryl, Braun, Germany) or NBCA-MS (n = 58; Glubran2, General Enterprise Marketing, Viareggio, Lucca, Italy). Handling, embolic efficacy, and safety of both NBCAs were compared according the fulfillment of a standardized embolization plan, the occlusive effect on the spermatic vein, and the sticking to the microcatheter. Statistical analysis was performed with the Mann-Whitney U test and the Fisher's exact test. Results: Patients of both study arms were comparable for age and clinical indication. Spermatic vein characteristics were comparable for varicocele classification and embolization side. Both NBCAs were equally efficient in occluding the spermatic vein and blocking reflux (NBCA, n = 54/54, 100% vs. NBCA-MS, n = 54/57, 94.7%; P = 0.244). The embolization plan could be accomplished in an equal number of veins for both groups (NBCA, n = 45/54, 83.3% vs. NBCA-MS, n = 41/58, 70.7%; P = 0.124). Adhesiveness of the glue to the microcatheter was the same in both NBCA groups (NBCA, n = 25/54, 46.3% vs. NBCA-MS, n = 29/58, 50%; P = 0.71). No glue-related complications were noted. Conclusions: NBCA and NBCA-MS are equally efficient and safe glues for embolization of varicoceles.
61 RADIATION PROTECTION AND DOSIMETRY↗
A comparative density functional study on electrical properties of layered penta-graphene
We present a comparative study of the influence of the number of layers, the biaxial strain in the range of −3% to 3%, and the stacking misalignments on the electronic properties of a new 2D carbon allotrope, penta-graphene (PG), based on hybrid-functional method within the density functional theory (DFT). In comparison with local exchange-correlation approximation in the DFT, the hybrid-functional provides an accurate description on the degree of p{sub z} orbitals localization and bandgap. Importantly, the predicted bandgap of few-layer PG has a weak layer dependence. The bandgap of monolayer PG is 3.27 eV, approximately equal to those of GaN and ZnO; and the bandgap of few-layer PG decreases slowly with the number of layers (N) and converge to 2.57 eV when N ≥ 4. Our calculations using HSE06 functional on few-layer PG reveal that bandgap engineering by stacking misalignment can further tune the bandgap down to 1.37 eV. Importantly, there is no direct-to-indirect bandgap transition in PG by varying strain, layer number, and stacking misalignment. Owing to its tunable, robustly direct, and wide bandgap characteristics, few-layer PG is promising for optoelectronic and photovoltaic applications.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Evolutionary analyses of non-family genes in plants
There are a large number of non-family (NF) genes that do not cluster into families with three or more members per genome. While gene families have been extensively studied, a systematic analysis of NF genes has not been reported. We performed comparative studies on NF genes in 14 plant species. Based on the clustering of protein sequences, we identified ~94,000 NF genes across these species that were divided into five evolutionary groups: Viridiplantae-wide, angiosperm-specific, monocot-specific, dicot-specific, and those that were species-specific. Our analysis revealed that the NF genes resulted largely from less frequent gene duplications and/or a higher rate of gene loss after segmental duplication relative to genes in both low-copy-number families (LF; 3 10 copies per genome) and high-copy-number families (HF; >10 copies). Furthermore, we identified functions enriched in the NF gene set as compared with the HF genes. We found that NF genes were involved in essential biological processes shared by all plant lineages (e.g., photosynthesis and translation), as well as gene regulation and stress responses associated with phylogenetic diversification. In particular, our analysis of an Arabidopsis protein-protein interaction network revealed that hub proteins with the top 10% most connections were over-represented in the NF set relative to the HF set. This research highlights the roles that NF genes may play in evolutionary and functional genomics research.
Ye, Chuyu↗
Transport of Poly(n-butylcyano-acrylate) nanoparticles across the blood-brain barrier in vitro and their influence on barrier integrity
Research highlights: {yields} Poly(n-butylcyano-acrylate) (PBCA) nanoparticles may be promising drug carriers. {yields} Influence of PBCA nanoparticles on the integrity of the blood-brain barrier in vitro. {yields} PBCA nanoparticles lead to a reversible disruption of the BBB in vitro after 4 h. {yields} Potential application as time-dependent and specific opener of the BBB. -- Abstract: In previous studies it was shown that polysorbate 80(PS80)-coated poly(n-butylcyano-acrylate) nanoparticles (PBCA-NP) are able to cross the blood-brain barrier (BBB) in vitro and in vivo. In order to explore and extend the potential applications of PBCA-NP as drug carriers, it is important to ascertain their effect on the BBB. The objective of the present study was to determine the effect of PS80-coated PBCA-NP on the BBB integrity of a porcine in vitro model. This has been investigated by monitoring the development of the transendothelial electrical resistance (TEER) after the addition of PBCA-NP employing impedance spectroscopy. Additionally, the integrity of the BBB in vitro was verified by measuring the passage of the reference substances {sup 14}C-sucrose and FITC-BSA after addition of PBCA-NP. In this study we will show that the application of PS80-coated PBCA-NP leads to a reversible disruption of the barrier after 4 h. The observed disruption of the barrier could also be confirmed by {sup 14}C-sucrose and FITC-BSA permeability studies. Comparing the TEER and permeability studies the lowest resistances and maximal values for permeabilities were both observed after 4 h. These results indicate that PS80-coated PBCA-NP might be suitable for the use as drug carriers. The reversible disruption also offers the possibility to use these particles as specific opener of the BBB. Instead of incorporating the therapeutic agents into the NP, the drugs may cross the BBB after being applied simultaneously with the PBCA-NP.
60 APPLIED LIFE SCIENCES↗
Conservation and diversity in the secondary forward photodynamics of red/green cyanobacteriochromes
Cyanobacteriochromes (CBCRs) are photosensitive proteins that are distantly related to the phytochrome family of photoreceptors and, like phytochromes, exhibit photoactivity initiated by the excited-state photoisomerization of a covalently bound bilin chromophore. The canonical red/green photoswitching sub-family is the most studied class of CBCRs studied to date. Recently, a comparative study of the ultrafast (100 fs–10 ns) forward photodynamics of nine red/green photoswitching CBCR domains isolated from Nostoc punctiforme were reported (S. M. Gottlieb, P. W. Kim, C.-W. Chang, S. J. Hanke, R. J. Hayer, N. C. Rockwell, S. S. Martin, J. C. Lagarias and D. S. Larsen, Conservation and Diversity in the Primary Forward Photodynamics of Red/Green Cyanobacteriochromes, Biochemistry, 2015, 54, 1028–1042). We extend this study by characterizing the secondary (10 ns–1 ms) forward photodynamics of eight red/green photoswitching CBCRs from N. punctiforme with broadband time-resolved absorption spectroscopy. We demonstrate that the dynamics of these representative red/green CBCRs can be separated into two coexisting pathways involving a photoactive pathway that is successful in generating the terminal light-adapted 15E P g population and an unsuccessful pathway that stalls after generating a meta-stable Lumi-O f intermediate. The photoactive pathway evolves through a similar mechanism from excitation of the dark-adapted 15Z P r state to generate a far-red absorbing Lumi-R f and then via a succession of blue-shifting photointermediates to ultimately generate the 15E P g state. This suggests a steady deviation from planarity of the bilin chromophore during the dynamics. While, the general mechanism for this evolution is conserved among these CBCBs, the timescales of these dynamics deviate significantly. Only half of the characterized CBCRs exhibit the unproductive pathways due to photoexcitation of dark-adapted 15Z P o sub-population that upon photoexcitation generates a meta-stable Lumi-O f intermediate, which eventually decays back to the 15Z P o subpopulation. 15Z P o is ascribed the horizontal Asp657 configuration that disrupts H-bonding with the chromophore in the dark-adapted state; its presence can be identified via enhanced absorption of high-energy tail of the electronic absorption spectrum.
59 BASIC BIOLOGICAL SCIENCES↗
Comparative ion insertion study into a nanostructured vanadium oxide in aqueous salt solutions
We present a comparative study for the electrochemical insertion of different cations into a nanostructured vanadium oxide material. The oxide is hydrothemally synthesized and electrically characterized by variable temperature measurements. The electrochemical reactions are performed in aqueous chloride solutions of lithium, sodium, potassium, and ammonium, and the electrochemical behavior of various cycles are correlated with visual changes in the vanadium oxide nanosheets as observed by scanning electron microscopy. We note an increase in the specific charge per cycle in the cases of sodium and ammonium ions only, correlated with minimal physical changes to the nanosheets. The differing behavior of the various ions has implications for their use in electrical energy storage applications.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗