Smoothing Spline ANOVA Models and their Applications in Complex and Massive Datasets

Complex and massive datasets can be easily accessed using the newly developed data acquisition technology. In spite of the fact that the smoothing spline ANOVA models have proven to be useful in a variety of fields, these datasets impose the challenges on the applications of the models. In this chapter, we present a selected review of the smoothing spline ANOVA models and highlight some challenges and opportunities in massive datasets. We review two approaches to significantly reduce the computational costs of fitting the model. One real case study is used to illustrate the performance of the reviewed methods

Evaluation of left ventricular function in patients with coronary slow flow: A systematic review and meta-analysis

Background: Coronary slow flow (CSF) is an angiographic finding defined as delayed distal vessel perfusion without severe stenosis of the epicardial coronary arteries. However, definite alterations in left ventricular (LV) function in patients with CSF remains inconsistent. This study aimed to clarify the changes in LV function in patients with CSF and explore the factors that may influence LV function. Methods: PubMed, Embase, and Cochrane Library databases were systematically searched. Standardized mean differences and 95% confidence intervals (CI) for the LV function parameters were calculated. Subgroup analysis, meta-regression analysis, and correlation analysis were performed to explore the factors influencing LV function. Results: Twenty-two studies (1101 patients with CSF) were included after searching three databases. In patients with CSF, LV ejection function in patients with CSF was marginally lower (61.8%; 95% CI: 61.0%, 62.7%), global longitudinal strain was decreased (–18.2%; 95% CI: –16.7%, –19.7%). Furthermore, left atrial diameter, left atrial volume index, and E/e′ were significantly increased, while E/A and e’ were significantly decreased. The mean thrombolysis in myocardial infarction frame count (TFC) was linearly associated with LV function; the larger the mean TFC, the greater the impairment of LV function. Conclusions: Left ventricular systolic and diastolic functions were impaired in patients with CSF, and this impairment was aggravated with increasing mean TFC

Size-induced axial band structure and directional flow of a ternary-size granular material in a 3-D horizontal rotating drum

Differences in the material property of the granular material induce segregation which inevitably influences both natural and industrial processes. To understand the dynamical segregation behavior, the band structure, and also the spatial redistribution of particles induced by the size differences of the particles, a ternary-size granular mixture in a three-dimensional rotating drum operating in the rolling flow regime is numerically simulated using the discrete element method. The results demonstrate that (i) the axial bands of the medium particles are spatially sandwiched in between those of the large and small ones; (ii) the total mass in the active and passive regions is a global parameter independent of segregation; (iii) nearly one-third of all the particles are in the active region, with the small particles having the highest mass fraction; (iv) the axial bands initially appear near the end wall, then become wider and purer in the particular species with time as more axial bands form toward the axial center; and (v) the medium particle type exhibits segregation later and has the narrowest axial bandwidth and least purity in the bands. Compared to the binary-size system, the presence of the medium particle type slightly increases the total mass in the active region, leads to larger mass fractions of the small and large particle types in the active region, and enhances the axial segregation in the system. The results obtained in the current work provide valuable insights regarding size segregation, and band structure and formation in the rotating drum with polydisperse particles.NRF (Natl Research Foundation, S’pore)Published versio

Research on the Application of Reductive Active Learning Method in the Design of Transmission Teaching Aids

In view of the dual pressure of examination oriented and extra-curricular counseling in primary education, this paper discusses the relationship between knowledge acquisition and perceptual experience through the design of teaching aids according to the educational concept of reductive active learning method. Based on life style as logic, the interesting transmission mode is established, and the mechanical knowledge related to force and transmission is transformed into teaching aids that conform to the cognitive law of children aged 6-12. Children get sensory experience through practical operation. Therefore, it enriches the content of science course in primary school, and establishes the perceptual experience foundation for the later learning of mathematics, machinery and physics

Research on the Application of Reductive Active Learning Method in the Design of Transmission Teaching Aids

In view of the dual pressure of examination oriented and extra-curricular counseling in primary education, this paper discusses the relationship between knowledge acquisition and perceptual experience through the design of teaching aids according to the educational concept of reductive active learning method. Based on life style as logic, the interesting transmission mode is established, and the mechanical knowledge related to force and transmission is transformed into teaching aids that conform to the cognitive law of children aged 6-12. Children get sensory experience through practical operation. Therefore, it enriches the content of science course in primary school, and establishes the perceptual experience foundation for the later learning of mathematics, machinery and physics

Impact of multi-hole-wall air coupling with air-staged technology on H2S evolution during pulverized coal combustion

The multi-hole-wall air coupling with air-staged technology (MH&AS) was developed for pulverized coal combustion to affect a simultaneous realization of multiple benefits, including prevention of high-temperature corrosion, highly efficient burning of pulverized coal, and low NOx emissions. In this work, the impact of MH&AS on H2S evolution under different conditions was investigated by applying a laboratory-scale MH&AS furnace to test its feasibility for preventing high-temperature corrosion. Some important inclusions were obtained: (i) the lack of multi-hole-wall air for Daheng (DH) coal combustion resulted in H2S concentration exceeding the critical value (namely, 100 ppm) causing high-temperature corrosion, but H2S near the wall could be completely eliminated with a multi-hole-wall air ratio (αm) of 0.1; (ii) the higher the pyrite content of the coal sample was or the smaller the particle size, the larger the H2S concentration near the wall; (iii) the four reactions leading to H2S formation were validated by Gibbs free energy and chemical equilibrium constant calculations. This study affirms the efficiency of MH&AS in mitigating the high-temperature associated with air-staged combustion

Detailed kinetic modeling of H₂S formation during fuel-rich combustion of pulverized coal

The paper presents a detailed kinetic study on H2S formation during fuel-rich combustion of pulverized coal via tube furnace experiment and kinetic analysis with Chemkin. A new detailed kinetic model involving 34 species and 115 reactions was developed, with emphasis on CS2 as a source for H2S. The novel model was validated using experimental data with respect to the concentration distributions of H2, CO, H2O, CO2, SO2, H2S, COS and CS2. Sensitivity analysis shows that H2S concentration was very sensitive to reactions (2) H2S + H = SH + H2, (89) SO2 + CO = SO + CO2, (104) COS + H2O = H2S + CO2, (62) HOSO (+M) = H + SO2 (+M), (103) CS2 + H2O = H2S + COS, etc. Also, SH, S, and SO were the key free radicals for H2S production. Rate of production analysis (ROP) were also performed, which indicate that SH was the most important precursor of H2S. Based on the detailed kinetic model and ROP analysis, the simplified reaction path of H2S formation was constructed. Finally, the new model was compared with the Leeds University sulfur chemistry model. The two models have the same key free radicals and four major elementary reactions. The main difference is that CS2 was a notable source for H2S in our model targeted for coal combustion, and should be given special attention.The work was supported by the National Natural Science Foundation of China (Grant No. 51706151); Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (STIP) (Grant No. 2019L0147); and Major Special Projects for the Innovative Demonstration Zone Construction of National Sustainable Development Agenda in Taiyuan

Reaction Mechanism for Sulfur Species during Pulverized Coal Combustion

Low-NOx combustion technologies are widely applied in pulverized coal-fired boilers. But it promotes the formation of high concentration of H₂S, which is one of the main reasons for high-temperature corrosion. To limit the H₂S formation, it is urgently necessary to reveal the evolution behavior of the sulfur species. In this work, the reaction mechanism for sulfur species was investigated using a tube-heating furnace for low-sulfur bituminous coal combustion. In the primary stage of combustion, the O₂ concentration decreased sharply. Meanwhile, the sulfur species of SO₂, H₂S, COS and CS₂, and significant amount of reductive gases CO and H₂, were generated. After the sulfur release finished, the distribution of the sulfur species in the downstream region depended on only the gas-phase reactions. With the reduction of CO and H₂, part of SO₂ was converted to H₂S and COS. There also exited some shift relationships among SO₂, H₂S, COS, and CS₂ in the presence of abundant of CO₂ and H₂O. On the basis of the experimental results and the principles of Gibbs free energy and chemical equilibrium constant, a new gas-phase reaction mechanism for sulfur species, consisting of 9 reactions, was established. Furthermore, the kinetic parameters were also determined by a strict mathematical optimization process, and the predication errors for sulfur species were within 20%. The new built mechanism was expected to provide great assistance for the control of H₂S formation and the prevention of the high-temperature corrosion