How to Control Hydrodynamic Force on Fluidic Pinball via Deep Reinforcement Learning

Deep reinforcement learning (DRL) for fluidic pinball, three individually rotating cylinders in the uniform flow arranged in an equilaterally triangular configuration, can learn the efficient flow control strategies due to the validity of self-learning and data-driven state estimation for complex fluid dynamic problems. In this work, we present a DRL-based real-time feedback strategy to control the hydrodynamic force on fluidic pinball, i.e., force extremum and tracking, from cylinders' rotation. By adequately designing reward functions and encoding historical observations, and after automatic learning of thousands of iterations, the DRL-based control was shown to make reasonable and valid control decisions in nonparametric control parameter space, which is comparable to and even better than the optimal policy found through lengthy brute-force searching. Subsequently, one of these results was analyzed by a machine learning model that enabled us to shed light on the basis of decision-making and physical mechanisms of the force tracking process. The finding from this work can control hydrodynamic force on the operation of fluidic pinball system and potentially pave the way for exploring efficient active flow control strategies in other complex fluid dynamic problems

Liquid metal embrittlement of a dual-phase Al0.7CoCrFeNi high-entropy alloy exposed to oxygen-saturated lead-bismuth eutectic

This paper reports a new liquid metal embrittlement (LME) system in which a dual-phase Al0.7CoCrFeNi (equimolar fraction) high-entropy alloy (HEA) is embrittled by lead-bismuth eutectic (LBE) at 350 and 500°C. At 350°C, (Ni, Al)-rich BCC phase is embrittled, leading to intragrain cracking within this phase, while the predominant cracking mode changes to BCC/FCC phase boundary decohesion at 500°C. At both temperatures, cracks are rarely seen in the (Co, Cr, Fe)-rich FCC phase, indicating that this phase is immune to LME. Furthermore, the results suggest a transition from an adsorption-dominated LME mechanism at 350°C to a phase boundary wetting-dominated LME mechanism at 500°C

1,25-Dihydroxyvitamin D inhibits hepatic diacyglycerol accumulation and ameliorates metabolic dysfunction in polycystic ovary syndrome rat models

Introduction: We aimed to evaluate the influence of 1,25-dihydroxyvitamin D (1,25(OH)2D) on metabolic dysfunction and elucidate its underlying mechanism using a rat model of polycystic ovary syndrome (PCOS).Methods: Twenty-four Sprague-Dawley rats were randomly divided into four groups: control group (CON, 2 ml/kg of oral 0.5% CMC), 1,25VD group (oral 0.5% CMC and 2.5 ug/kg intraperitoneal 1,25(OH)2D), PCOS group (1 mg/kg oral letrozole), PCOS+1,25VD group (1 mg/kg oral letrozole orally 2.5 ug/kg intraperitoneal 1,25(OH)2D). The treatments were administered for 8 weeks. Body weight, estrus cycle, insulin tolerance, and oral glucose tolerance of the rats in the different groups were assessed. The rats were euthanized at the 8th weeks, and plasma, ovarian, and liver samples were collected and analyzed. The hepatic lipid profile was characterized using HPLC/MRM.Results: Letrozole-induced PCOS rats exhibited increased weight, insulin resistance, postprandial glucose abnormalities, and dyslipidemia. Compared with the PCOS group rats, the PCOS+1,25VD group rats showed reduced body weight, increased sensitivity to insulin, decreased postprandial glucose, and elevated levels of high-density lipoprotein cholesterol. Moreover, abnormally increased liver concentrations of total diacylglycerol (DG) and DG species in the PCOS rats were reversed by treatment with 1,25(OH)2D. Additionally, hepatic DG and insulin sensitivity were correlated.Conclusion: 1,25(OH)2D inhibited hepatic DG accumulation and ameliorated metabolic dysfunction in PCOS rat models

Regulating the coordination mode of Ti atoms in the beta zeolite framework to enhance the 1-Hexene Epoxidation

Regulating the Ti active sites in titanosilicates with different coordination modes is of prime scientific and industrial significance to the rational design of efficient catalysts for olefin epoxidation. In this study, the Ti species in Ti-beta zeolite catalysts (open/closed tetra-coordinated Ti sites, hexa-coordinated Ti species, and TiO2) were keenly controlled via the dealumination-metallization approach. By multiple characterizations, kinetics study, and multivariate model analysis, it is found that the open tetra-coordinated framework Ti(OH)(OSi)3 species contribute more to the catalytic performance for 1-hexene epoxidation with H2O2. Moreover, the Ti-beta with rich open tetra-coordinated Ti(OH)(OSi)3 species showed significantly improved reaction performance (TON: 401, conversion: 64%, selectivity: 98%, H2O2 efficiency: 97%) with lower apparent activation energy. This study not only opens up new prospects for the design of efficient titanosilicates by modifying Ti microenvironments but also proposes the strategy to improve the content of open tetra-coordinated Ti sites

OCT-Precoding Combined with LDPC-Coding Scheme for 128 QAM MB-OFDM UWBoF System

In this paper, we proposed a coding scheme based on orthogonal cyclic transpose (OCT) precoding combined with low-density parity check (LDPC) code to improve the transmission performance of 128-quadrature amplitude modulation multiband orthogonal-frequency-division-multiplexing ultrawide band over fiber (128 QAM MB-OFDM UWBoF) system. The proposed scheme could not only improve the performance of the system but also average the signal-to-noise ratio (SNR) of subcarriers and reduce the difference among subchannels in practical application. The simulation results showed that compared with the traditional scheme, the receiver performance of this scheme was improved by 2.7 dB when the LDPC-coding rate was 87.5% through 70 km standard single mode fiber (SSMF) transmission and the bit error rate (BER) was 3.8 × 10−3. Besides, the constellation distribution was more convergent and uniform

Intergranular precipitation-enhanced wetting and phase transformation in an Al0.4CoCrFeNi high-entropy alloy exposed to lead-bismuth eutectic

After exposure to oxygen-poor (10^-13–10^-14 wt%) liquid lead-bismuth eutectic (LBE) at 500°C for 500 h, LBE penetrates more than one order of magnitude deeper in an FCC Al0.4CoCrFeNi high-entropy alloy (HEA) deco-rated with a network of BCC (Ni, Al)-rich intergranular (IG) precipitates than in a single-phase, FCC Al0.3CoCrFeNi HEA without the IG precipitate network. This deterioration of corrosion resistance is attributed to the energetic nature of the BCC/FCC interphase boundaries (IBs) and resultant IB wetting. The LBE ingress film selectively leaches nickel located at those low-indexed crystalline planes, resulting in phase transformation from FCC to BCC structure.National Natural Science Foundation of China, United States Department of Energy, Office of Nuclear Energy's Nuclear Energy University Program

Retrospective clinical study of renin-angiotensin system blockers in lung cancer patients with hypertension

Purpose Renin-angiotensin system blockers (RASBs), which include angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-2 receptor 1 blockers (ARBs), have been reported to be associated with lung cancer metastasis, radiotherapy and chemotherapy. Until now, very limited clinical data for RASBs’ diagnostic and prognostic effects has existed for lung cancer chemotherapy in Chinese patients. Methods There were a total of 678 lung cancer patients with hypertension, of which 461 (68%) were in the non-RASBs group and 217 (32%) were in the RASBs group. Patients’ gender, age, smoking status, histologic differentiation, tumor size, pathological grade, lymph node metastasis, pathological stage and progression-free survival (PFS) were retrospectively analyzed between these two groups. The clinical effects of ACEIs and ARBs in lung cancer patients were compared via t tests, and χ2 test, and potential prognostic factors for progression-free survival (PFS) were evaluated by Kaplan–Meier analysis. Results Significant differences were observed in lymph node metastasis between the RASBs and non-RASBs groups. The RASBs group (62.8% vs 71.7%, p = 0.037) and ARBs group (60.0% vs 71.7%, p = 0.030) had lower lymph node metastasis, and patients with RASBs had a lower pathological stage than those in non-RASBs groups (67.1% vs 77.4%, p = 0.044 ). The PFS of the RASBs (10.7 vs. 6.7 months, p = 0.040) and ACEIs (12.9 vs 6.7 months, p = 0.021) groups were longer than that of the non-RASBs group, while no statistical difference was shown between the ACEIs and ARBs groups. Moreover, the significant results of PFS were further confirmed in pathological stage III–IV patients. In the non-RASB group, 55% of patients took calcium channel blockers (CCBs), and the ACEIs group have a significantly longer PFS compared to the non-CCBs group (6.4 vs 12.9 months, p = 0.036). Conclusion In this study, we showed that the use of RASBs is a positive factor for pathological stage and prognosis of lung cancer patients. Therefore, it is necessary to actively evaluate medical history, especially the use of anti-hypertension medication, in patients with lung cancer and reflect medical history in the treatment and management plans of these patients

Interfacial superstructures and chemical bonding transitions at metal-ceramic interfaces

Metal-ceramic interfaces are scientifically interesting and technologically important. However, the transition of chemical bonding character from a metal to a nonoxide ceramic is not well understood. The effects of solute segregation and interfacial structural transitions are even more elusive. In this study, aberration-corrected electron microscopy is combined with atomic-resolution energy-dispersive x-ray and electron energy loss spectroscopy to investigate Ti-, V-, and Cr-segregated WC-Co interfaces as model systems. The experiments reveal the general anisotropic formation of reconstructed trilayer-like superstructures with segregant-specific compositional profiles that facilitate the transition from covalent to metallic electronic structures. Density functional theory calculations confirm the gradual increasing metallicity from WC to Co in the interfacial trilayers via increasing metallic solute concentration. This study uncovers unprecedented details of the sophisticated interfacial superstructures at metal-ceramic interfaces. It sheds light on how a metal transits to a ceramic at a "general" interface with strong segregation