Scale Growth Research Articles

Contribution of Y2O3/Hf co-doping to alumina scale growth on oxide dispersion strengthened Co-based superalloy

Effect of Y2O3/Hf co-doping on the growth of the alumina scale formed on an oxide dispersion strengthened (ODS) Co-10Ni-20Cr-15Al (at%) superalloy at 900 °C in air was investigated. On both superalloys with and without Y2O3/Hf co-doping, a distinctive layered alumina scale consisting of an outer θ-alumina and an inner α-alumina was formed. Y2O3/Hf co-doping could reduce the oxidation growth rate of the θ- and α-alumina layers and improve the spallation resistance of the scale by suppressing the formation of interfacial pores. The reactive element effect in the θ-alumina has been initially elucidated in detail with the aid of 3D-AP characterization.

An efficient visual exploration approach of geospatial vector big data on the web map

The visual exploration of geospatial vector data has become an increasingly important part of the management and analysis of geospatial vector big data (GVBD). With the rapid growth of data scale, it is difficult to realize efficient visual exploration of GVBD by current visualization technologies even if parallel distributed computing technology is adopted. To fill the gap, this paper proposes a visual exploration approach of GVBD on the web map. In this approach, we propose the display-driven computing model and combine the traditional data-driven computing method to design an adaptive real-time visualization algorithm. At the same time, we design a pixel-quad-R tree spatial index structure. Finally, we realize the multilevel real-time interactive visual exploration of GVBD in a single machine by constructing the index offline to support the online computation for visualization, and all the visualization results can be calculated in real-time without the external cache occupation. The experimental results show that the approach outperforms current mainstream visualization methods and obtains the visualization results at any zoom level within 0.5 s, which can be well applied to multilevel real-time interactive visual exploration of the billion-scale GVBD.

Oxidation behaviour of Zr added hypereutectic Nb-19Si-5Mo-20Ti alloy

The influence of Zr (3 at%) addition on non-isothermal and isothermal oxidation behaviour of the Nb-19Si-5Mo-20Ti (base alloy) has been investigated. During heating in a thermogravimetric analyser to 1300 °C in air, the mass-gain begins at ∼600 °C, and shows a more gradual rise as well as a lower peak value for the Zr-containing alloy compared to the base alloy. Furthermore, the Zr-containing alloy exhibits superior oxidation resistance in isothermal test for 24 h at 1100 °C, but not at 900 °C and 1200 °C, probably due to the differences in oxide scale growth kinetics and defect density. The oxidation products have been identified as Nb2O5, SiO2, TiO2, MoO2, TiNb2O7, Ti2Nb10O29 for both the alloys, with ZrO2 being additionally observed in the Zr-containing alloy. Analysis of the isothermal oxidation kinetics suggests an initial stage of interface-reaction controlled rapid mass increase followed by parabolic behaviour, where oxygen diffusion through the oxide scale is apparently rate-controlling. Slow down to parabolic kinetics is ascribed to the formation of a SiO2-rich compact oxide scale. The oxide scale becomes protective due to reduced oxygen anion diffusivity in Nb2O5 having Mo, Ti and Zr as substitutional solute, along with the formation of ZrO2 and TiO2 with Pilling-Bedworth ratio less than 2.

Dynamic trajectory partition optimization method based on historical trajectory data

Partitioning dynamic trajectory data can improve the efficiency and accuracy of trajectory data processing, provide a foundation for trajectory data mining and analysis. However, with the continuous growth of trajectory data scales and the urgent demand for trajectory query efficiency and accuracy, partitioning methods have become crucial. The partitioning method of dynamic trajectory data faces significant challenges in terms of spatiotemporal trajectory locality, partition load balancing, and partition time. To address these challenges, we propose a method based on historical trajectory pre-partitioning, which can store data more effectively in distributed systems. We partition similar historical trajectory data to achieve preliminary partitioning of the data. In addition, we also construct a cost model to ensure that the workload of each partition is close to consistency. Extensive experiments have demonstrated the excellent partitioning efficiency and query efficiency achieved by our design compared to other partitioning methods.

Co-WO3 composite coating on ferritic stainless steel interconnects

In order to apply Co-WO3 composite coating to SUS 430 steel interconnects for solid oxide fuel cell (SOFC) interconnects, a combination of electrophoresis and electroplating is used, followed by thermal energy exposure to ambient temperature at 800 ℃ for up to 5 weeks. The thermal growth of the oxide scale displays a tri-layer structure with a Cr2O3 layer in the inner part, a CoWO4 layer in the middle and (Co,Fe)3O4 and Co3O4 layer in the outer part. Co-WO3 coating produces an oxide layer that not only prevents Cr2O3 development and outward transport of Cr species but also enhances the electrical behavior of the surface scale.

Spectra scaling of velocity components and pressure–strain correlations for hypersonic boundary layers at a range of wall-to-recovery temperatures

Flow similarity is one of the most desirable features for turbulence under different conditions. For hypersonic boundary layers, different wall temperatures are known to change the turbulence evolution by influencing the intercomponent energy transfer, while the flow similarity has received less attention. Based on direct numerical simulations, this work investigates the spectral distribution of velocity components and pressure–strain correlations for hypersonic boundary layers at Mach 6 and wall-to-recovery temperature ratios equal to 0.3, 0.5, 0.76, and 1. The wall-normal evolution of turbulent structures is compared by the spectra peak scale λSP, wall-normal location ySP, and the vertical profiles of peak scale λP. For all cases, the peak scale profiles exhibit linear increases with a height of 0.1≤y/δ≤0.25. The linear growth of the turbulence scale in the logarithmic region indicates the existence of self-similar structures, and the agreement of peak scales in the outer scaling suggests the flow similarity under different wall temperatures. Likewise, the streamwise pressure–strain term has the peak scale profile linearly dependent on the height for the same vertical range 0.1≤y/δ≤0.25 with velocity components, while the wall-normal and spanwise terms exhibit both linear and constant vertical dependence depending on the wall temperatures. With the increase in wall temperature, the peak scale exhibits broader constant vertical dependence and narrower linear vertical dependence. The cospectral analysis further confirms that the pressure–strain correlations are maximized at different spanwise-vertical aspect ratios of turbulence structures.

Summary of the 2022 Report on Cardiovascular Health and Diseases in China.

Recent decades have seen the remarkable development of China in medical accessibility and quality index, and the application of a number of new advanced cardiovascular technologies benefits more patients. However, according to the Annual Report on Cardiovascular Health and Diseases in China published in this article, which was organized and summarized by National Center for Cardiovascular Diseases, there is still a huge population living with risk factors of cardiovascular diseases (CVD), and the morbidity and mortality of CVD are increasing. It is estimated that there are around 330 million patients suffering from CVD currently, including 245 million of hypertension, 13 million of stroke, 45.3 million of peripheral artery disease, 11.39 million of coronary heart disease (CHD), 8.9 million of heart failure, 5 million of pulmonary heart disease, 4.87 million of atrial fibrillation, 2.5 million of rheumatic heart disease, and 2 million of congenital heart disease. Tobacco use, diet and nutrition factors, physical activity, overweight and obesity, and psychological factors are what affect cardiovascular health, while hypertension, dyslipidemia, diabetes, chronic kidney disease, metabolic syndrome, and air pollution are the risk factors for CVD. In this article, in addition to risk factors for CVD, we also report the epidemiological trends of CVD, including CHD, cerebrovascular disease, arrhythmias, valvular heart disease, congenital heart disease, cardiomyopathy, heart failure, pulmonary vascular disease and venous thromboembolism, and aortic and peripheral artery diseases, as well as the basic research and medical device development in CVD. In a word, China has entered a new stage of transforming from high-speed development focusing on scale growth to high-quality development emphasizing on strategic and key technological development to curb the trend of increasing incidence and mortality of CVD.

On the high temperature oxidation behavior of AlCrBN/TiAlNbSiN multilayer coatings with addition of boron and silicon

Developing a TiAlN-based hard coating with a multilayer structure comprising multiple nitride components shows potential to enhance the overall performance of high temperature applications. In this study, multi-target cathodic arc evaporation was utilized to deposit multilayer coatings comprising of nanostructured AlCrN/TiAlNbN and AlCrBN/TiAlNbSiN. The focus of this study is to analyze how the different coatings undergo structural changes due to the growth of oxide scale and diffusion processes that take place during oxidation when subjected to high temperatures of 900 °C, and the roles of B and Si addition in their oxidation resistance were examined. The deposited AlCrN/TiAlNbN coating showed a typical columnar structure with nanolayer stacking (average bilayer periodic thickness ~ 14.8 nm). The surface formed an oxide layer rich in titanium oxide, while the internal oxide layer of the AlCrN/TiAlNbN coating that underwent oxidation contained mixed metal oxides with a dominant composition of Al2O3, which hindered additional oxidation. The AlCrBN/TiAlNbSiN coatings, which had average bilayer periodic thickness 11.4 nm ~12.2 nm, showed fine-fibrous growth morphologies and refining effects of B and Si in the AlCrBN/TiAlNbSiN coatings, and they possessed better high temperature oxidation resistance thang that of AlCrN/TiAlNbN. Due to the formation of a protective oxidized layer with a combination of metal oxides, which minimizes the inward diffusion of oxygen during oxidation, the AlCrBN/TiAlNbSiN coating with a thicker AlCrBN layer exhibited the highest resistance to oxidation compared to the other coatings studied.

Supersonic spray derived Cu–Co oxide coating on SUS441 to protect the metallic interconnect and to increase stability of SOFC cathode

The interconnects for solid oxide fuel cells (SOFCs) are usually ferritic stainless steels such as SUS441. These steels have issues of oxidation and Cr diffusion under the operational high temperatures, which can cause serious deterioration of the cathode performance. In order to improve the electrode stability and the oxidation resistivity, this work deposits Cu–Co oxide coating on SUS441 interconnects via room-temperature supersonic spray using fine CuCo2O4 spinel-based oxide powders synthesized via a combustion process. The coating can significantly inhibit the growth of chromium oxide scale on the steel surface and increase the interconnect conductivity by a factor of 4.4 in 200-hr oxidation test in air. The coating effectively prevents Cr diffusion to the cell composed of La0·6Sr0·4FeO3-δ electrode and La0·8Sr0.2Ga0.8Mg0·2O3-δ electrolyte. As a result, the coating substantially increases the cathode performance by reducing the interfacial polarization resistance and improving the stability in 100-hr test at 800 °C. This study demonstrates that this high-performance protective Cu–Co oxide coating has a promising application prospect for SOFC interconnects.

Computational Modeling of Walking Beam Type Reheat Furnace for the Prediction of Slab Heating and Scale Formation

Abstract Computational modeling using the high-viscosity laminar flow approach was applied to study the effect of slab crossing time on slab heating and scale growth. Simulation of an existing industrial walking beam reheating furnace with four zones, outer refractory body, skid, slab, and fluid zone is considered. The fuel used was a mixture of coke oven and blast furnace gas. Preheated air is supplied co-axially with the fuel mixture. The combustion simulation is performed using the constrained equilibrium mixture fraction model. From the results, it has been observed that with an increase in slab residence time, the slab temperature and scale growth increase across the slab. For the system considered, with a fuel mass flowrate of 70,000 kg/h, 150–180 min of slab crossing time is appropriate to obtain desired slab temperature at the discharge end. The overall equivalence ratio is taken as Φ = 1 (fuel/air ratio is the same as stoichiometric ratio). The maximum slab scale thickness is evaluated as 2.4 mm at the discharged end for 180 min of slab crossing time.

QuickFPS: Architecture and Algorithm Co-Design for Farthest Point Sampling in Large-Scale Point Clouds

Point clouds have been employed extensively in machine perception applications. Farthest point sampling (FPS) is a critical kernel for point cloud processing. With the rapid growth of point cloud scale, FPS introduces a large number of memory accesses, which become the bottleneck of the large-scale point cloud processing. In this paper, we present QuickFPS, an architecture and algorithm co-design of farthest point sampling in large-scale point clouds. First, We systemically analyze the characteristics of FPS and put forward a bucket-based farthest point sampling algorithm. The algorithm introduces a two-level tree data structure to organize the large-scale point cloud into multiple buckets. By using two mechanisms named merged computation and implicit computation for the buckets, the external memory accesses and compute cost are significantly reduced. Then, we design an efficient domain-specific accelerator for farthest point sampling in large-scale point clouds. The accelerator takes advantage of different forms of parallelism and further improves the accelerator’s efficiency. Finally, we evaluate QuickFPS with several widely used point cloud datasets, which include small-scale and large-scale point clouds (up to 120,000 points). Overall, QuickFPS achieves performance speedups of 43.4x and 12.2x compared to GTX 1080Ti GPU and state-of-the-art point cloud accelerator PointAcc, respectively.

AI Empowered Net-RCA for 6G

6G is envisioned to offer higher data rate, improved reliability, ubiquitous AI services, and support massive scale of connected devices. As a consequence, 6G will be much more complex than its predecessors. The growth of the system scale and complexity as well as the coexistence with the legacy networks and the diversified service requirements will inevitably incur huge maintenance cost and efforts for future 6G networks. Network Root Cause Analysis (Net-RCA) plays a critical role in identifying root causes of network faults. In this article, we first give an introduction about the envisioned 6G networks. Next, we discuss the challenges and potential solutions of 6G network operation and management, and comprehensively survey existing RCA methods. Then we propose an artificial intelligence (AI)- empowered Net-RCA framework for 6G. Performance comparisons on both synthetic and real-world network data are carried out to demonstrate that the proposed method outperforms the existing method considerably.

Abundance of natural resources, government scale and green economic growth: An empirical study on urban resource curse

Based on panel data of Chinese cities in 2000–2020, this study analyzed the impact of natural resources abundance on green economic growth at the urban level, and also examined the mediated effect of government scale. The findings of the study reveal that: The “resource curse” phenomenon in China's various cities is significant. The relationship between environmental regulation intensity and green economic growth presented as “U-shaped curve”. The impeding effect of industrial structure, as well as the promoting effect of factors such as economic openness level, technical innovation and physical capital investment on the development of green economy were significant. However, the marketization level and education level did not show significant impact on green economic growth. Natural resources abundance can produce “curse” effect on green economic growth by promoting the expansion of government expenditure scale and government personnel scale. Government institutional reform policies can effectively alleviate the “resource curse” phenomenon in various cities. Therefore, this study argued that optimizing the government internal expenditure structure, reshaping the political incentive structure and reducing administrative regulations in the natural resources industries were effective ways to optimize the government expenditure scale and alleviate the urban “resource curse”. Scientifically determining the government personnel scale, reducing the scope and intensity of government intervention, and fully leveraging the public's social supervision function were effective ways to optimize the government personnel scale and alleviate the “Resource curse” of cities.

Typology Mapping of Small Border Islands in the Context of Optimizing the Role as a Center for Regional Growth and Environmental Supporting Capacity in Anambas Islands Regency

As an autonomous region consisting of a cluster of small islands in the northern border area of the Unitary State of the Republic of Indonesia, Anambas Islands Regency has a remote geographical location, inadequate transportation conditions, and limitations in providing infrastructure, especially basic service infrastructure. The implication of the role as an autonomous region, raises the existence of growth centers on a district scale and other scale growth centers along with economic activities in them on several existing small islands. The role as a growth center on small islands requires the continued provision of sufficient production and distribution resources to meet population consumption growth. The sustainability of the carrying capacity of the environment on the one hand is faced with the role and function of small border islands as regional growth centers that have the potential to develop in the future on the other hand. Based on these problems, it is necessary to map the typology of small islands in order to optimize the role as a center for regional growth and environmental carrying capacity in Anambas Islands Regency. By mapping the typology of small border islands, policy directions for sustainable regional development can be determined for each small border island.

Fear of missing out dan personal growth initiative pada mahasiswa

Abstrak. Students’ inability to adapt can cause students to become stressed and pessimistic. Students who feel stressed and pessimistic indicate that the student has poor Personal Growth Initiative (PGI) and will more easily experience Fear of Missing Out (FoMO). The purpose of this research is to see the relationship between FoMOt and PGI in students. The respondents of this research were 394 students who were studying in Indonesia. The sampling technique uses convenience sampling. This research was measured using the Fear of Missing Out Scale (FoMOS) and Personal Growth Initiative Scale-II (PGIS-II). The results of the analysis were carried out using a correlation test with a value of r=0.009; p=0.853 (p>0.05) does not show a relationship between FoMO and PGI in students. The results of this research show that high or low levels of PGI are not necessarily influenced by the level of FoMO in students. Keyword: Child of divorce, defense mechanism, psychological well-being

Evaluation of Post-Larval Diets for Indoor Weaned Largemouth Bass (Micropterus salmoides).

This study aimed to evaluate different commercial diets (Otohime C1, Aller Futura (AF), Biomar Inicio Plus (BIP)) and one experimental feed (EF) in terms of their effectiveness as post-larval diets for indoor weaned largemouth bass, LMB (Micropterus salmoides). Key variations in the content of nutritive values were monounsaturated fatty acid (MUFA) and highly unsaturated FA (HUFA) ω3. Fish were fed with one of four tested diets from the 33rd to the 40th day post-hatch (DPH). Biometric indices, digestive enzyme-specific activities, thyroid hormone status, and mRNA expression of genes coding for skeleton, neuron, and muscle growth were analyzed. The lowest skeletal deformity rate and highest survival among the treatments were seen in BIP-fed fish. Dietary lipids, with an appropriate balance between MUFA and polyunsaturated FA (PUFA), alongside amino acid balance, were shown to be the main contributors to the growth of the skeleton and/or fish survival. On the other hand, fish growth is correlated with fish digestive capacity and feed moisture percent rather than feed quality. Unexpectedly, BIP-fed fish were attributed with the lowest expression of skeleton differentiation markers, which may reflect the sacrifice of scale and/or cranium growth at the expense of somatic growth. This study highlights the role of non-marine ingredients in the nutrition of post-larval LMB.

Reynolds number dependence of azimuthal and streamwise pipe flow structures

This paper revisits the study by Baileyet al.(J. Fluid Mech., vol. 615, 2008, pp. 121–138), adopting a higher-fidelity calibration approach to reveal subtle flow variations with Reynolds numbers that were not discernible previously. The paper aims therefore to provide insights into the characteristics of azimuthal and streamwise pipe flow structures adopting two-point joint statistics and spectral analysis for shear Reynolds numbers in the range$2\times {10^3}\le {Re_\tau }\le {16\times {10^3}}$, where${Re_\tau }$is based on the wall friction velocity$u_{\tau }$, the pipe radius$R$, and the fluid kinematic viscosity$\nu$. The streamwise velocity fluctuations were measured at four wall-normal locations,$0.1\le {x_{{2}}/R}\le {0.7}$, covering the logarithmic and core regions of fully developed turbulent pipe flow based on 35–41 azimuthal probe separations using, simultaneously, two single hot-wire probes. A uniquein situcalibration approach for both probes was adopted where a potential flow was insured, resulting in consistent and precise pipe flow data. The azimuthal velocity correlation, the cross-power spectral density and the coherence function of the streamwise velocity fluctuations are discussed, revealing a clear dependence of the azimuthal scales of the large and very large flow motions on the wall-normal location, the azimuthal separation, the streamwise wavenumber and the Reynolds number. Along the logarithmic region, a linear growth of the azimuthal scales of the large- and very-large-scale structures was observed; however, they do scale nonlinearly and reach their maximum sizes in the core region, i.e. near the centreline of the pipe. Additionally, the streamwise very-large- and large-scale motions were evaluated using the premultiplied energy spectra, showing wavelengths${\approx }{18R}$and${\approx }{3R}$for${Re_{\tau }}\approx {16\times {10^3}}$at half of the pipe radius, respectively.

Towards Sustainable Development: Investigating the Heterogeneity and Driving Factors of Green Total Factor Productivity in Coal Enterprises

Understanding the heterogeneity and driving factors of green total factor productivity (GTFP) in coal enterprises can provide guidance for policy design regarding the sustainable development of coal in the future. In contrast to previous research at the macro level, we adopt and extend the data envelopment analysis method to measure and quantitatively decompose the GTFP of coal enterprises, examine inter-enterprise heterogeneity at multiple levels, explain the effects of the key driving factors and moderating factors of GTFP in theory, and subsequently conduct empirical testing using data obtained from 639 coal enterprises in China. The results indicate that there is significant inter-enterprise heterogeneity in GTFP in terms of enterprise scale, enterprise growth stage, government–enterprise collusion (GEC), and regional differences. The enterprise scale and enterprise growth stage have significantly positive effects on GTFP, while GEC has a significantly negative effect on GTFP. Technological progress, scale efficiency, and pure technical efficiency have moderating effects on enterprise scale, enterprise growth stage, and GEC. The results have valuable policy implications; it is necessary for the government to allocate significant resources towards thoroughly examining the potential effects arising from the heterogeneity of GTFP among coal enterprises, to weaken control over the aggregate target, and to strengthen the use of market-oriented policy instruments.

Protectionism's impact on embodied energy flows among 43 countries: An assessment based on input-output structural decomposition model

Free trade has made developed economies transfer a great deal of energy-intensive industries to developing economies, which induces more energy consumption in developing economies. The global spread of COVID-19 has led to trade protectionism that directly undermine the international free trade system. This paper is aimed to explore how trade protectionist measures affect global embodied energy flows, taking the case for 43 typical economies. Firstly, we combine the multi-regional input-output analysis and scenario analysis to construct an accounting framework of embodied energy consumption under free trade and restricted trade scenarios. The impact of trade protection on 43 economies' energy flows is discussed from the perspective of industrial sectors and disaggregated value chain links. Secondly, the role of technology, structure and scale factors in the protection's impact on embodied energy consumption is discussed based on structural decomposition analysis. The results indicate that under the scenario of trade-free, global energy consumption is 3880.91 million tons of oil equivalent. Under the scenario of trade-restricted, global energy consumption is 4435.56 million tons of oil equivalent, and global trade protection measures would increase global energy consumption by 554.65 million tons of oil equivalent. Trade of final products, trade of last-stage intermediate products and trade of other-stage intermediate products of the value chain contributed 42.7%, 40.5% and 16.8%, respectively, with the manufacturing industry facing the biggest impact. For emerging developing economies, such as China and Russia, their domestic energy consumption would decrease by 193.52 and 163.74 million tons of oil equivalent due to export tightening, respectively, while for developed economies, trade protection would result in an increase of 343.31 million tons of oil equivalent in EU countries. In addition, structural change and scale growth are the main factors that promote energy consumption growth under the trade restriction scenario, making it increase by 66% and 21% respectively.

Effect of Si2BC3N additions on the oxidation of Ta4HfC5 ceramics at 900–1100 °C

Si2BC3N content held the key on the oxidation scale growth and damage mechanism of Ta4HfC5 ceramics oxidized at 900–1100 °C. Si2BC3N addition increased the oxidation scale thickness due to the micro-pores generated by BN(C) oxidation constructing oxygen-diffusion channel. However, Ta4HfC5-10 wt% Si2BC3N showed better oxidation resistance in the Ta4HfC5-5–20 wt% Si2BC3N ceramics, resulting from the dynamic equilibrium of pores healing and tantalum-hafnium silicate glass generation. Generally, Ta4HfC5 tended to oxidize firstly followed by the oxidation of Si2BC3N, whereas oxidizing products of Si2BC3N like substantial B2O3 and few SiO2 were insufficient to the formation of dense oxide scale at 900–1100 °C.