Early Stage Of Deposition Research Articles

Early stages of polycrystalline diamond deposition: laser reflectance at substrates with growing nanodiamonds.

The chemical vapor deposition of polycrystalline diamond (PCD) films is typically done on substrates seeded with diamond nanoparticles. Specular laser reflectance has been used in tandem with a continuous film model to monitor the thickness of these films during their deposition. However, approaches to gain information on properties that strongly affect film morphology, such as the areal density of seeds, remain largely unexplored. This work outlines a strategy for using laser reflectance measurements to refine the monitoring of film thickness during deposition, estimate the mean equivalent radii and the areal density of seeds, and estimate growth incubation periods. We present a general model based on the Rayleigh theory of scattering for laser reflectance at substrates with growing nanoparticles that captures the early stages of PCD deposition. We test our model experimentally by depositing diamond under identical conditions on silicon substrates with various seed densities and by comparing seed densities obtained by scanning electron microscopy to those determined by our strategy. We also explore the different deposition stages for which our model and a continuous film model can be used safely. In addition to providing guidelines for characterizing PCD deposition, this work may also advance the general understanding of nanoparticle growth and formation.

Mathematical Modeling of Wax Deposition in Field-Scale Crude Oil Pipeline Systems

The formation of solid wax crystals, which interlock and form a gel-like layer on the inner wall of the crude oil pipeline, influences the transportation of waxy crude oil. The deposited layer grows continuously and hardens during the oil transportation, reducing the effective inside diameter of the crude oil pipeline and the flow rate. In extreme cases, the deposited layer may block the crude oil pipeline leading to a loss of production and capital investment. In this paper, wax deposition from multiphase flow in field-scale oil pipeline transport systems has been studied. The novelty of this work is to develop a mathematical model that incorporates water-in-oil emulsions, wax precipitation kinetics, molecular diffusion, and shear dispersion to enable accurate predictions of both the wax deposit growth rate and aging of the deposit. The coupled nonlinear partial differential equations governing the flow are discretized in time by a second-order semi-implicit time discretization scheme based on the Adams-Bashforth and Crank-Nicolson methods, which completely decouples the computation of the governing equations. The resulting temporal schemes are discretized in space by the bivariate spectral collocation method based on Chebyshev-Gauss-Lobatto grid points and simulated in MATLAB software to obtain the profiles of the flow variables. The simulation results are presented in graphical and in tabular forms and discussed. This study found that the deposit thickness is directly proportional to the Reynolds number and inversely proportional to the mass Grashof number, Schmidt number, and Weber number. Deposit aging is rampant during the early stages of wax deposition, after which it stabilizes at a specific value as time elapses. A deposition model to predict the wax deposit thickness and aging is proposed in this study. The findings of this study will help in making informed decisions on the planning of pigging operations, thermal insulation, and other remediation techniques to be applied in controlling wax deposition in field-scale crude oil pipeline systems.

Adherence of Escherichia coli and blood elements in titanium discs submitted to anodic oxidation. In vitro study

Modifications of implants by means of surface treatments are performed to optimize the biochemical interactions of the bone deposition process. However, if on the one hand they favor the adhesion of blood elements, on the other hand they can also enable the formation of biofilm. This study evaluated the adherence of blood cells and Escherichia coli in titanium discs submitted to surface treatments by anodic oxidation (OA), sandblasting followed by acid etching (JAT) compared with untreated discs (Li). To evaluate the adherence of microorganisms were performed: atomic force microscopy; Field Emission Gun Scanning Electron Microscopy (FEG-SEM); biofilm formation was evaluated by spectrophotometer turbidity analysis and colony forming unit (CFU/mL) before and after simulated brushing. For blood cell adherence, the blood collected from a patient was deposited and fixed on the discs and analyzed in the FEG-SEM being classified according to the "Blood Element Adherence Index". The results showed a slight increase in the adhesion of microorganisms in samples treated by anodic oxidation. However, the microorganisms were distributed singly and not in conglomerates, with no biofilm formation unlike the Li group. Regarding the adherence of blood elements, the Li group showed higher adherence and lower amount was found in the JAT group, but there was no statistically significant difference between the groups. The results of this study suggest that anodic oxidation treatment may favor the adherence of blood cells and fibrin mesh, contributing to the early stages of bone deposition.

Early striatal amyloid signal in Down Syndrome: Comparison of PiB and Florbetapir PET

AbstractBackgroundPET amyloid [11C]PiB imaging has revealed early detection of Ab in the striatum in individuals with Down Syndrome (DS), a group carrying genetic risk for AD. The goal of this investigation is to examine striatal binding of [11C]PiB and [18F]florbetapir (FBP) to determine if similar striatal uptake profiles are observed in individuals with DS.MethodsPET scans were acquired as part of the Alzheimer’s Biomarker Consortium – Down Syndrome (ABC‐DS) study. DS participants were scanned with either PiB (n=204; ages 25‐56 yrs) or FBP (n=84; ages 40‐85 yrs) at seven academic sites. SUVR images were created with acquisition times of 50‐70min for both radiotracers, using a cerebellar reference region. ROIs were defined for the anterior ventral striatum (AVS) and the full cortex (CTX). SUVR was then converted to centiloids (CL) using published methods (Klunk 2015) with DS‐specific modifications, including AVS extraction and approximate CL_AVS. Aβ(+) was defined using a threshold of 18.1 CL in CTX ROI, categorizing Aβ(‐) and Aβ(+) groups. Comparisons across PiB and FBP examined 1) the proportion of CL_AVS values exceeding the threshold in the Aβ(‐) group and 2) the difference between SUVR_AVS and SUVR_CTX in the Aβ(+) group.Results58/204 subjects (PiB) and 72/84 subjects (FBP) were Aβ(+), with differences in Aβ(+) presumably due to greater age and advanced neurodegeneration in the FBP group. For the Aβ(‐) comparison, elevated CL_AVS was detected in 16/146 (PiB) and 0/12 (FBP). The average CL_AVS of those that exceeded the threshold was 37.0±12.7 CL (PiB) (mean±SD). For the Aβ(+) comparison, 52/58 (PiB) and 52/72 (FBP) had CL_AVS greater than their CL_CTX. The average difference between SUVR_AVS and SUVR_CTX for the Aβ(+) group was 0.50±0.39 SUVR (46.9±36.8 CL) (PiB) and 0.08±0.18 SUVR (14.2±31.0 CL) (FBP).ConclusionsPiB PET exhibited higher uptake in the striatum during early stages of amyloid deposition. PiB revealed a 6x greater difference than FBP between striatal to cortical SUVR in the Aβ(+) group. Neuropathological investigation is ongoing to characterize these differences in striatal binding in DS. Despite this difference in early‐stage binding, both PiB and FBP demonstrate sensitivity for determining the presence of Aβ in DS.

Carbon isotopes of n-alkanes allow for estimation of the CO2 pressure in the Early Jurassic - A case study from lacustrine shale and cannel boghead in the Dachanggou Basin, Xinjiang, Northwest China

The carbon isotope composition of sedimentary organic matter (OM) records abundant climate and environmental information, and a case from the Early Jurassic Badaowan Formation (northern Xinjiang) in Northwest China based on the integration of organic petrography, biomarkers, the carbon isotope composition of n-alkanes and the total organic carbon of coal and oil shale is presented. The results show that total organic carbon isotopes (δ13CTOC) are affected by the OM source composition, while carbon isotopes of n-alkanes show different variations. The fractionation of the two types of isotopes responds differently with varying precision to climate and environmental changes. The OM source is the main factor causing the fractionation of total organic carbon isotopes, and the fractionation of δ13C of n-alkanes reflects atmospheric CO2 pressure (pCO2). According to the covariation between the δ13C of n-alkanes in C3 plants and pCO2, the pCO2 during the deposition of oil shale and coal in the Lower Jurassic Badaowan Formation is restored. In the early stage of oil shale deposition, a higher pCO2 corresponds to a higher inertinite content, pointing to an increase in the fire frequency. Some of the lacustrine cannel boghead interbedded with oil shale is also correlated with a high pCO2, promoting biological productivity in lakes (including the surrounding hinterland) and the formation of lacustrine cannel boghead. The sedimentary archive variation in pCO2 exhibits periodicity, and lacustrine shale has the potential to act as a registering fluctuation of pCO2 at a higher resolution.

Sediment provenance of the Lulehe Formation in the Qaidam basin: Insight to initial Cenozoic deposition and deformation in northern Tibetan plateau

AbstractUnravelling early Cenozoic basin development in northern Tibetan Plateau remains crucial to understanding continental deformation mechanisms and to assessing models of plateau growth. We target coarse‐grained red beds from the Cenozoic basal Lulehe Formation in the Qaidam basin by combining conglomerate clast compositions, paleocurrent determinations, sandstone petrography, heavy mineral analysis and detrital zircon U–Pb geochronology to characterize sediment provenance and the relationship between deformation and deposition. The red beds are dominated by matrix‐supported, poorly sorted clastic rocks, implying low compositional and textural maturity and short transport distances. Although most sandstones have high (meta)sedimentary lithic fragment contents and abundant heavy minerals of metamorphic origin (e.g., garnet, epidote and chlorite), spatiotemporal differences in detrital compositions are evident. Detrital zircon grains mainly have Phanerozoic ages (210–280 Ma and 390–480 Ma), but Proterozoic ages (750–1000 Ma, 1700–2000 Ma and 2300–2500 Ma) are also prominent in some samples. Analysed strata display dissimilar (including south‐, north‐ and west‐directed) paleocurrent orientations. These results demonstrate that the Cenozoic basal deposits were derived from localized, spatially diverse sources with small drainage networks. We advocate that initial sedimentary filling in the northern Qaidam basin was fed by parent‐rocks from the North Qaidam‐South Qilian belts and the pre‐Cenozoic basement within the Qaidam terrane interior, rather than southern distant Eastern Kunlun regions. Seismic and drilling well stratigraphic data indicate the presence of paleohighs and syn‐sedimentary reverse faults and noteworthy diversity in sediment thickness of the Lulehe Formation, revealing that the Qaidam terrane exhibited as several isolated depocenters, rather than a coherent basin, in the early stage of the Cenozoic deposition. We suggest the Cenozoic Qaidam basin to have developed in a contractional deformation regime, which supports models with synchronous deformation throughout most of Tibet shortly after the India‐Eurasia collision.

Last Interglacial decadal sea surface temperature variability in the eastern Mediterranean

The Last Interglacial (~129,000–116,000 years ago) is the most recent geologic period with a warmer-than-present climate. Proxy-based temperature reconstructions from this interval can help contextualize natural climate variability in our currently warming world, especially if they can define changes on decadal timescales. Here, we established a ~4.800-year-long record of sea surface temperature (SST) variability from the eastern Mediterranean Sea at 1–4-year resolution by applying mass spectrometry imaging of long-chain alkenones to a finely laminated organic-matter-rich sapropel deposited during the Last Interglacial. We observe the highest amplitude of decadal variability in the early stage of sapropel deposition, plausibly due to reduced vertical mixing of the highly stratified water column. With the subsequent reorganization of oceanographic conditions in the later stage of sapropel deposition, when SST forcing resembled the modern situation, we observe that the maximum amplitude of reconstructed decadal variability did not exceed the range of the recent period of warming climate. The more gradual, centennial SST trends reveal that the maximal centennial scale SST increase in our Last Interglacial record is below the projected temperature warming in the twenty-first century.

Quantitative analysis of circulating levels of vimentin, clusterin and fibulin-5 in patients with pseudoexfoliation syndrome and glaucoma

Pseudoexfoliation (PEX) is a multifactorial age-related disease involving deposition of extracellular fibrillar material on anterior ocular tissues. If left untreated, the early stage of deposition termed as pseudoexfoliation syndrome (PEXS) may lead to the advanced stage of pseudoexfoliation glaucoma (PEXG) characterised by increased intraocular pressure, damage to the optic nerve and subsequent irreversible blindness. The etiology of PEX is complex and identification of novel factors associated with the disease is needed. This study aimed to identify the involvement of vimentin in pseudoexfoliation pathology and assess the levels of vimentin, clusterin and fibulin-5 in the circulating fluids of PEX patients compared to controls. Eighty-seven participants (35 controls, 35 PEXS and 17 PEXG) were enrolled for this case-control study. The expression of vimentin in lens capsules of patients and age-sex matched controls was assayed by qRT-PCR, western blotting and immunohistochemistry. Aqueous humor (AH) vimentin levels and plasma levels of vimentin, clusterin and fibulin-5 were assayed through ELISA. Increased vimentin was observed in the lens capsule of patients compared to controls at mRNA and protein levels. Compared to control (11.5 ± 1.4 ng/ml [±SEM]), the AH vimentin concentrations were significantly higher (ANOVA p = 0.01) in PEXS (16.4 ± 1.8 ng/ml) and PEXG (20.1 ± 2.5 ng/ml). Compared to controls (372.2 ± 15.1 ng/ml), plasma vimentin levels were significantly higher (ANOVA, p < 0.001) in PEXS (449.9 ± 15.7 ng/ml) and PEXG (535.5 ± 25.0 ng/ml). The plasma and aqueous humor levels of vimentin showed a positive correlation of 0.31. The plasma levels of clusterin were 298.9 ± 19.0 μg/ml, 367.8 ± 25.6 μg/ml and 272.9 ± 16.8 μg/ml in controls, PEXS and PEXG, respectively and were significantly higher in PEXS (p = 0.03) compared to control. Plasma fibulin-5 levels were 149 ± 32.2 pg/ml, 187.6 ± 32.3 pg/ml and 203.8 ± 27.3 pg/ml in controls, PEXS and PEXG, respectively and there was no significant difference in its levels between the groups (ANOVA p = 0.49). In conclusion, vimentin is upregulated in PEX affected eyes. Increased vimentin levels in plasma and AH differentiate PEXS and PEXG from controls.

High-resolution magnetostratigraphic records of the pliocene sedimentary successions in Yengisar section, NW China, and its tectonic implications

The Neogene strata upward-coarsening sandstone and conglomerate sequences at the periphery of the Northeastern Pamir record the intense uplift of the paleosurface of the building mountains. To further improve our knowledge of source-sink processes, a detailed magnetostratigraphic investigation was carried out along the Yengisar section, which is located at the southwestern margin of the Tarim Basin. The new high-resolution magnetostratigraphic data revealed that the Artux Formation was deposited from 4.9 Ma to 1.9 Ma with three sedimentation rates changes. The variations in sedimentation rate may be due to the pulsating exhumation of the Western Kunlun Mountain, caused by the northward motion of the Pamir salient. By integrating the evidences from the seismic reflection profile and other magnetostratigraphic investigations in this region, the basal age of the Xiyu Formation and the early stages of growth strata deposition were estimated at ∼1.9 and 1.45 Ma, respectively. Based on the data, we propose that the progradation of the Xiyu Formation and the migration of the deformation front are the two independent responses of the sink region to the uplift events of the source region.

Early transverse tubule involvement in cardiomyocytes in hereditary transthyretin amyloidosis: a possible cause of cardiac events

BackgroundCardiac involvement is one of the most frequent and fatal manifestations of hereditary transthyretin (ATTRv) amyloidosis. This study sought to clarify the pathogenesis of ATTRv amyloidosis, specifically, how transthyretin (TTR) amyloid begins to deposit in cardiomyocytes and how this deposition progresses in these cells. MethodsWe analyzed autopsy cardiac tissues from five patients with ATTRv amyloidosis by using confocal microscopy with thioflavin S staining and immunofluorescence and electron microscopy to demonstrate the pattern of TTR amyloid deposition in cardiomyocytes. ResultsWe demonstrated predominant amyloid deposition in the transverse tubules (t-tubules) of cardiomyocytes at the early stage of TTR amyloid deposition. Also, a pattern of the progression of amyloid deposition from deeply invaginated extracellular matrix, that is, t-tubules, to cell surface extracellular matrix, that is, basement membrane, was noted. Three-dimensional confocal microscopic images revealed the abnormal architecture of the t-tubules with nodular swelling, branching, and confluence in the cardiomyocytes with amyloid deposition. Double immunofluorescence staining with anti-TTR antibody and CACNA1C antibody demonstrated reduced voltage-dependent calcium channels around amyloid deposition. ConclusionsOur pathological study demonstrated that t-tubule involvement is an early event in cardiomyocytes in the pathogenesis of ATTRv amyloidosis. This finding may indicate that disruption of t-tubules in cardiomyocytes may contribute to the pathogenesis of cardiac events including heart failure and arrhythmia.

Thickness Dependence of Cu-layer-based Transparent Heaters

In this study, ultrathin (4-40 nm) Cu-layer-based transparent heaters prepared on glass substrates were investigated for cost-effective applications. The Cu heaters were embedded between ZnO layers serving as anti-reflection and anti-corrosion layers. The Cu layer thicknesses varied in the range of 4-40 nm, and the corresponding structural, electrical, optical and thermal properties were evaluated. Cu was found to follow the Volmer-Weber 3D growth mode in the early deposition stage, where isolated islands grow and coalesce to form a continuous layer at ~12 nm. In the thickness regime of discontinuous Cu layers, a significant increase in sheet resistance was observed due to the reduced current paths and the high severity of electron scattering at the Cu/ZnO interfaces. Because of light absorption associated with the localized surface plasmon resonance (LSPR) in the presence of pores in the films, visible transparency peaks near the thickness of the complete film-closure, beyond which stronger light absorption decreases transparency. The sheet resistance of the transparent heaters was modulated in the range of 0.8-96.2 Ω/sq. The heating characteristics well follow Joule’s law which predicts a higher temperature for a lower-resistance heater at a given voltage. The measured temperature-power relation is linear, from which the important heater parameter of convective heat transfer coefficient is extracted.

Cell and dendrite growth of tungsten by atmospheric pressure chemical vapor deposition

In this study, tungsten coatings are deposited at 300–610 °C from WF6 and H2 by atmospheric pressure chemical vapor deposition (APCVD). Tungsten powders adheres to the furnace walls (cold wall furnace) in every deposition, regardless of whether the coating is dense or not. These tungsten powders are proved to be produced by homogeneous reactions in gas phase near the substrate and adheres to the furnace inner wall as they move with the fluid. The presence of tungsten powders when depositing dense tungsten coatings indicates that the homogeneous reactions contribute to the growth of dense tungsten coatings; with this premise, the kinetics, structure and growth mode of tungsten coatings in APCVD system are discussed. Activation energy of 28.7 and 61.9 kJ/mol corresponded to rate-limiting steps of the diffusion of the tungsten atoms in gas phase, and the dissociation of H2. The<100>orientated columnar grains along the growth direction (GD) are main-branches. Not all but majority of the small grains intercalated between the columnar grains orient in the direction close to<111>along the GD, and these small grains are proved to be parts of second-branches. In the early stage of deposition, the<100>orientated grains compete with each other due to the growth of the cell tips in width. Raised areas are found on the surfaces of pyramids, and the microstructure of the growth interface shows that flat interface is prone to curved when there are more favorable growth conditions ahead. These results reveal that homogeneous reactions lead to the cell and dendrite growth mode of tungsten coatings in APCVD system.

Homoepitaxial overgrowth of (111) diamond films on Au-coated and Ni-coated substrates

Homoepitaxial growth of (111)-oriented diamond films on the Au-coated and Ni-coated diamond substrates by microwave plasma chemical vapor deposition (CVD) has been investigated. The process is involved with overgrowth of CVD diamond on Au and Ni islands formed by hydrogen plasma annealing of the 20 nm Au and Ni film coatings on diamond substrates. Cross-sectional transmission electron microscopy (TEM) observations show that both of the Au and Ni islands as single crystallites are in epitaxy with diamond substrate and no diamond growth occurs on top of those islands in the early stage of diamond deposition. The overgrowth of diamond over the metal islands results in excellent coalescence to form a continuous film with a lower defect density than the film without the metal coating. With such Au and Ni islands, the film stress can be further relaxed as shown with Raman spectroscopy.

Stress Analysis of Tungsten Deposition in a 3D Trench Mold With Regard to Initial Nuclei Shape

Tungsten has been commonly used for fine interconnects due to its good gap-filling characteristics in 3D molds, such as trench patterns. However, tungsten shows high deposition stress. This causes mold distortion because tungsten has low ad-atom mobility, and diffusion-driven relaxation does not occur. To reduce tungsten’s deposition stress, the shape of the nuclei can be controlled, which is an effective way to suppress the mechanical deformation caused by the formation of a grain boundary between free surfaces during the coalescence stage. In this study, elliptical tungsten nuclei with various aspect ratios, which suppress coalescence in the early stage of deposition, were proposed to reduce the deposition stress. Stress was calculated using the finite element method (FEM) in the range of 0.5 to 8 radius ratios of the tungsten nuclei. The bending of the trench mold was calculated due to tungsten stress and additional coalescence between films during the filling process. As a result, the wider the elliptical nucleus was, the lower the film stress, and mold bending between line patterns was also reduced. The defects in the depth and width of the periodic trench influenced the mold bending in the early growth stage and the stage of coalescence between films, respectively.

Protonation of graphene oxide electrolyte during electrophoresis and effects on deposited film properties

Electrophoretic deposition (EPD) is widely used to prepare graphene oxide (GO) thin films. However, changes in the GO electrolyte under different EPD parameters and its impact on film properties are yet to be investigated. In this study, we report on GO solution separation into a clear supernatant and sediment through a voltage dependent sedimentation process. We relate the observed sedimentation to the dual effect of electrophoresis and water electrolysis at the electrode interface, which contributes to the protonation of GO at the anode. Current measurements during EPD indicate that the anodic deposition at low potentials is controlled by the concentration change of GO in the electrolyte. Conversely, at higher potentials, delamination of coating due to gas evolution has a significant influence on film growth. Spectroscopic and microscopic measurements reveal that the deposited layers at all potentials were GO. However, X-ray photoemission spectra (XPS) show reduced amounts of oxygen functionalities of films obtained at the early stages of deposition for lower potentials. This we relate to GO flake-size effects as opposed to an interface reduction reported in literature. These results present new insight into electrophoresis and associated surface and chemical structure of deposited GO. Additionally, it also provides a cost effective, scalable method of separating GO in bulk from solution during its synthesis and in applications where separation of the GO-based final product is required.

Silica Shell Growth on Vitreophobic Gold Nanoparticles Probed by Plasmon Resonance Dynamics

The early stages of silica deposition on vitreophobic citrate-capped gold nanoparticles (AuNPs) are studied using in situ optical spectroscopy supported by electron microscopy and hydrodynamic size...

First-Principles Calculation and Multi-Scale Observation for a Carbon Deposition on a SOFC Anode Near the Interface

Carbon deposition site in the Ni/YSZ was studied through microscale observation and first-principles calculation. Early stage of carbon deposition was appropriate reaction to determine the active site because the carbon worked as a visible marker. SEM observation showed that the carbon deposition was progressed not in the overall Ni surface but in the specific sites such as the Ni/YSZ interfaces at low temperature. STEM-HAADF showed that the graphite layer was not found on the Ni(111) surface but on the Ni(112) surface, indicating that the unsaturated step facets such as Ni(112) enhanced the carbon deposition. Similar trends were found in the first-principles calculation. The CH adsorption energy in the Ni(112) facet was higher than that in the Ni(111) facet. In addition, it was suggested that the YSZ structure also influenced the carbon deposition as well as the Ni facet.

Robust 2D Simulation of Morphological Evolution in Lithium-Metal Batteries

The lithium-metal battery is drawing a lot of attention being among the top candidates for the next-generation batteries. This is due to the possibility of achieving high redox potential and specific capacity. While lithium plating is the key to the high specific capacity, the surface morphology deteriorates over cycles due to evolution of dendrites and dead lithium1. This results in capacity loss as well as safety risk due to the possibility of internal short-circuit caused by dendrites piercing through the separator2. Unfortunately, there is still a lack of understanding of the conditions that lead to such undesired interfacial phenomena. To understand and minimize these phenomena, it is crucial to have detailed physics-based 2D model and ability to perform robust simulations. Recently, we have provided well-defined 2D models relevant for lithium metal battery and elucidated the significance of rigorous convergence analysis3.In the present work, we will discuss the morphological evolution over cycles as predicted by the proposed 2D moving boundary model using experimentally relevant parameters and conditions. One of the goals of this work is to find experimentally relevant conditions that lead to dendritic growth and gain insights into changes in surface morphology as the cell is cycled. The model equations are obtained through rigorous mathematical formulation of the relevant physical phenomena, and lithium seed, which is observed at the early stage of lithium deposition, is considered in the initial geometry for the simulation. The geometrical parameters used are based on experimental measurements reported in the literature4. In addition to the robust simulation with in-house moving boundary model codes, COMSOL Multiphysics, a commonly used commercial solver for battery simulations, is also used and results are compared. In particular, both phase field and moving mesh methods will be compared. Effect of parameters, and the choice of algorithms will be critically analyzed. Acknowledgments This research was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy (DoE) through the Advanced Battery Materials Research Program (Battery500 Consortium). Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. References K. N. Wood, E. Kazyak, A. F. Chadwick, K. H. Chen, J. G. Zhang, K. Thornton, and N. P. Dasgupta, ACS Cent. Sci., 2, 790-801 (2016).J. Liu, Z. Bao, Y. Cui, E. Dufek, J. B. Goodenough, P. Khalifah, Q. Li, B. Liaw, P. Liu, A. Manthiram, Y. S. Meng, V. R. Subramanian, M. F. Toney, V. V. Viswanathan, M. S. Whittingham, J. Xiao, W. Xu, J. Yang, X. Yang, and J. Zhang, Nat. Energy, 14 180-186 (2019).K. Shah, A. Subramaniam, L. Mishra, T. Jang, M. Z. Bazant, R. D. Braatz, and V. R. Subramanian, J. Electrochem. Soc., 167, 133501 (2020).A. Pei, G. Zheng, F. Shi, Y. Li, and Y. Cui., Nano Lett., 17, 1132-1139 (2017).

Variations of cooling performance on turbine vanes due to incipient particle deposition

In this paper, to demonstrate the deposition effects on cooling performance, the changing patterns of film cooling due to particle deposition are numerically investigated on a turbine vane that is cooled by an array of film-holes. The uniqueness of this work is addressing the cooling performance at an early deposition stage, in which deposits are relatively slight. The build-ups of the deposits are simulated by moving grid nodes on the wall boundaries. Results show that in addition to particle velocity, the blowing conditions and wall temperatures are two important factors to determine the deposition patterns. Increasing coolant-to-mainstream mass flow ratios and lowering wall temperatures can help inhibit the growth of deposits. In addition, the modifications of the vane profile due to incipient deposition are completely different from those with excessive deposition. Although flow fields are less sensitive to the early-stage deposits in the subsonic vane passage, cooling effectiveness is significantly changed and the changes are linked to the mass flow ratios. Compared to the cooling performance from a non-deposition case, reduced cooling performance due to incipient deposition is found at a low mass flow ratio of 1.09%, while cooling performance is improved at moderate and high mass flow ratios of 1.64% and 2.06%.

Lattice Boltzmann multicomponent model for direct-writing printing

We introduce a mesoscale approach for the simulation of multicomponent flows to model the direct-writing printing process, along with the early stage of ink deposition. As an application scenario, alginate solutions at different concentrations are numerically investigated alongside processing parameters, such as apparent viscosity, extrusion rate, and print head velocity. The present approach offers useful insights on the ink rheological effects upon printed products, susceptible to geometric accuracy and shear stress, by manufacturing processes such as the direct-writing printing for complex photonic circuitry, bioscaffold fabrication, and tissue engineering.