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Diesel vehicles have caused serious environmental problems in China. Hence, the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI standard. To fulfill this stringent legislation, two major technical routes, including the exhaust gas recirculation (EGR) and high-efficiency selective catalytic reduction (SCR) routes, have been developed for diesel engines. Moreover, complicated aftertreatment technologies have also been developed, including use of a diesel oxidation catalyst (DOC) for controlling carbon monoxide (CO) and hydrocarbon (HC) emissions, diesel particulate filter (DPF) for particle mass (PM) emission control, SCR for the control of NOx emission, and an ammonia slip catalyst (ASC) for the control of unreacted NH

Zijia Liu,1 Guangyan Xu,1 Yuelun Zhang,2 Hanyu Duan,3 Yuanyuan Zhu,4 Li Xu1 1Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China; 2Medical Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China; 3Department of Anesthesiology, Tibet Autonomous Region People’s Hospital, Lhasa, People’s Republic of China; 4Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of ChinaCorrespondence: Li Xu, Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100730, People’s Republic of China, Tel +86 10 6915 2020, Fax +86 10 6915 5580, Email pumchxuli@163.comPurpose: Guidelines have not recommended routine transthoracic echocardiography (TTE) for elderly patients prior to noncardiac surgery. We aimed to evaluate the significance of preoperative TTE to predict perioperative cardiac complications (PCCs) for elderly patients with coronary artery disease (CAD) undergoing noncardiac surgery.Patients and methods: We retrospectively reviewed 2204 patients over 65 years of age with CAD who underwent TTE before intermediate- or high-risk noncardiac surgery in a teaching hospital in China between September 2013 and August 2019. The revised cardiac risk index (RCRI) was assessed. PCCs comprised acute coronary syndrome, heart failure, new-onset severe arrhythmia, nonfatal cardiac arrest, and cardiac death. Logistic regression was used to build the prediction model for PCCs. Discrimination was evaluated using receiver operating characteristic curves, and a nomogram of the predictive model was constructed.Results: PCCs occurred in 189 (8.6%) patients. Multivariable analysis showed that eight clinical risk factors (age, history of myocardial infarction, insulin therapy for diabetes, New York Heart Association classification, preoperative serum creatinine, preoperative electrocardiogram ST-T abnormality and pathological Q wave, and American Society of Anesthesiologists classification) and five TTE parameters (left atrial anteroposterior dimension, left ventricular ejection fraction, left ventricular diastolic dysfunction, pulmonary hypertension, and regional ventricular wall motion abnormality) were associated with PCCs. The receiver operating characteristic curve for the clinical plus TTE model provided better discrimination for PCCs compared with the RCRI model (area under the curve: 0.731 vs 0.564; P < 0.001) and the clinical model (area under the curve: 0.731 vs 0.697, P = 0.001), respectively. The clinical plus TTE model was presented as a prognostic nomogram.Conclusion: Preoperative TTE may help predict PCCs in elderly patients with CAD undergoing noncardiac surgery, and the prognostic nomogram from this study appeared to be useful for the assessment of perioperative cardiac risk.Keywords: transthoracic echocardiography, elderly, coronary artery disease, noncardiac surgery, perioperative cardiac complication

Selective catalytic reduction of NO

Stressed plants and polymer production can emit many unsaturated volatile organic esters (UVOEs). However, secondary organic aerosol (SOA) formation of UVOEs remains unclear, especially under complex ambient conditions. In this study, we mainly investigated ethyl methacrylate (EM) ozonolysis. Results showed that a substantial increase in secondary H2SO4 particles promoted SOA formation with increasing SO2. An important reason was that the homogeneous nucleation of more H2SO4 at high SO2 level provided greater surface area and volume for SOA condensation. However, increased primary H2SO4 with seed acidity enhanced EM uptake but reduced SOA formation. This was ascribed to the fact that the ozonolysis of more adsorbed EM was hampered with the formation of surface H2SO4 at higher particle acidity. Moreover, the increase in secondary H2SO4 particle via homogeneous nucleation favored to the oligomerization of oxidation products, whereas the increasing of primary H2SO4 with acidity in the presence of seed tended to promote the functionalization conversion products. This study indicated that the role of increased H2SO4 to EM-derived SOA may not be the same under different ambient conditions, which helps to advance our understanding of the complicated roles of H2SO4 in the formation of EM-derived SOA.

Ammonia leakage from the aftertreatment of diesel vehicles arouses serious environmental concerns, thus demanding a high-efficiency ammonia elimination catalyst. In the present work, the mechanism ...

The role of silver species in the H2-assisted NH3 selective catalytic reduction of NOx (H2-NH3-SCR) over Ag/Al2O3 catalysts was investigated by operando spectroscopy (DRIFTS-MS and DR-UV–Vis) and Density Functional Theory (DFT) calculation. UV–Vis analysis showed that several kinds of silver species were present on the Ag/Al2O3, including dispersed silver cations, partially oxidized silver clusters, metallic silver clusters, and silver nanoparticles. Operando DRIFTS-MS experiments showed that the reduction of NOx was dependent on the formation rate of nitrates, which was closely related to the silver content, H2 concentration, and reaction temperature. Notably, operando DR-UV–Vis experiments unambiguously confirmed that the metallic silver clusters were the active sites for nitrates formation, and the reduction of silver nitrates was much slower than NO oxidation. DFT calculations further revealed that reducing silver nitrates required higher energy barriers than NO oxidation, while H2 dissociation could occur on metallic silver clusters with a moderate energy barrier. In conclusion, metallic silver clusters contributed to the formation of nitrates and H2 dissociation, and the reduction of silver nitrates was the rate-determining step in the overall H2-NH3-SCR reaction.

Ag/Al2O3 catalysts containing different precipitable silver compounds (AgCl, Ag2SO4, and Ag3PO4) were synthesized and investigated for NOx reduction in H2-assisted C3H6-selective catalytic reduction (SCR). The samples were systematically characterized by N2 adsorption, X-ray diffraction (XRD), UV–Vis, X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). N2 adsorption revealed that the introduction of anions (Cl–, SO42–, and PO43–) did not significantly affect the surface and structural properties of the Al2O3 support. However, XRD patterns and HR-TEM images indicated that the addition of Cl– anions caused the agglomeration of silver species to form large AgCl particles on the AgCl/Al2O3 catalysts. In contrast, the silver species dispersed well on Ag2SO4/Al2O3 and Ag3PO4/Al2O3 catalysts. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that partial oxidation of C3H6 on Ag2SO4/Al2O3 produced large amounts of reactive enolic species, while it tended to yield inert formate on AgCl/Al2O3. As a result, Ag2SO4/Al2O3 catalysts, especially 3% Ag2SO4/Al2O3, exhibited superior water and sulfur tolerance in H2-assisted C3H6-SCR.

Zijia Liu,1 Guangyan Xu,1 Li Xu,1 Yuelun Zhang,2 Yuguang Huang1 1Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, People’s Republic of China; 2Central Research Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, People’s Republic of ChinaCorrespondence: Li Xu Tel +86 10 6915 2020Fax +86 10 6915 5580Email pumchxuli@163.comPurpose: Ever-increasing noncardiac surgeries are performed in patients aged 80 years or over with coronary artery disease (CAD). The objective of the study was to explore the incidence and risk factors of perioperative cardiac complications (PCCs) for the oldest-old patients with CAD undergoing noncardiac surgery, which have not been evaluated previously.Patients and Methods: A total of 547 patients, aged over 80 years, with a history of CAD who underwent noncardiac surgery were enrolled in this retrospective study. Perioperative clinical variables were extracted from the electronic medical records database. The primary outcome was the occurrence of PCCs intraoperatively or within 30 days postoperatively, defined as any of the following complications: acute coronary syndrome, heart failure, new-onset severe arrhythmia, nonfatal cardiac arrest, and cardiac death. Multivariate logistic regression analysis and multivariate Cox regression model were both performed to estimate the risk factors of PCCs. The incidence of PCCs overtime was illustrated by the Kaplan–Meier curve with a stratified Log-rank test.Results: One hundred six (19.4%) patients developed at least one PCC, and 15 (2.7%) patients developed cardiac death. The independent risk factors contributing to PCCs were age ≧85 years; body mass index ≧30 kg/m2; the history of angina within 6 months; metabolic equivalents < 4; hypertension without regular treatment; preoperative ST-T segment abnormality; anesthesia time > 3 h and drainage ≧200 mL within 24 h postoperatively.Conclusion: The incidence of PCCs in elderly patients over 80 years with CAD who underwent noncardiac surgery was high. Comprehensive preoperative evaluation, skilled surgical technique, and regular postoperative monitoring may help to reduce the occurrence of PCCs in this high-risk population.Keywords: oldest-old, coronary artery disease, noncardiac surgery, perioperative, cardiac complications

In this work, the Cu-SSZ-39 catalyst was sulfated at different temperatures (200 °C, 400 °C or 600 °C) in the presence of water to investigate the effects of sulfation on its catalytic performance in NH3-SCR. Sulfation at 200 °C and 400 °C resulted in a significant decrease in NOx conversion at low temperatures, while sulfation at 600 °C showed only slight effect on the SCR activity of Cu-SSZ-39. The coverage of active sites by H2SO4 was the main reason for the deactivation of the catalyst sulfated at 200 °C and 400 °C, while the formation of stable CuSO4 species should also be responsible for the catalytic activity loss of the catalysts sulfated at 200 °C, 400 °C and 600 °C. After regeneration at 600 °C, the activities of the sulfated catalysts could be recovered partially but were still lower than those of the fresh catalysts, due to the formation of stable sulfated Cu species.

A series of cerium-doped iron–titanium composite oxide catalysts (FeCeaTi, a = 0.1–1.0) prepared by a urea homogeneous precipitation method were investigated for selective catalytic reduction of NOx with NH3 (NH3-SCR). Over all the FeCeaTi samples, a promotion effect for NOx reduction was induced by the introduction of cerium, with the FeCe0.3Ti catalyst exhibiting the best catalytic performance, even at a high GHSV of 250 000 h−1. As indicated by kinetic studies, interestingly, the FeCe0.3Ti catalyst exhibited a higher activation energy for the NH3-SCR process while possessing a pre-exponential factor three orders of magnitude higher than that of FeTi. Going deeper, extensive characterization including N2-physisorption, XRD, Raman, NH3/NOx-TPD, XPS, EPR, and H2-TPR was carried out. XRD and Raman results showed that the introduction of suitable amounts of Ce into the FeTi samples promoted the dispersion of Fe and Ti. Such higher dispersion of these two components increased the capacities for NOx adsorption and activation and weakly bonded ammonia over FeCe0.3Ti, thus promoting the occurrence of the L–H pathway of NH3-SCR at low temperatures. H2-TPR results indicated that the reduction of FeCe0.3Ti occurred at a higher temperature than that of FeTi, which may be a reason for its higher activation energy for NH3-SCR.

Intraoperative hypothermia is a common complication during operations and is associated with several adverse events. Postoperative cognitive dysfunction (POCD) and its adverse consequences have drawn increasing attention in recent years. There are currently no relevant studies investigating the correlation between intraoperative hypothermia and POCD. The aim of this study was to assess the effects of intraoperative hypothermia on postoperative cognitive function in rats undergoing exploratory laparotomies and to investigate the possible related mechanisms. We used the Y-maze and Morris Water Maze (MWM) tests to assess the rats’ postoperative spatial working memory, spatial learning, and memory. The morphological changes in hippocampal neurons were examined by haematoxylin-eosin (HE) staining and hippocampal synaptic plasticity-related protein expression. Activity-regulated cytoskeletal-associated protein (Arc), cyclic adenosine monophosphate-response element-binding protein (CREB), S133-phosphorylated CREB (p-CREB [S133]), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor 1 (AMPAR1), and S831-phosphorylated AMPAR1 (p-AMPAR1 [S831]) were evaluated by Western blotting. Our results suggest a correlation between intraoperative hypothermia and POCD in rats and that intraoperative hypothermia may lead to POCD regarding impairments in spatial working memory, spatial learning, and memory. POCD induced by intraoperative hypothermia might be due to hippocampal neurons damage and decreased expression of synaptic plasticity-related proteins Arc, p-CREB (S133), and p-AMPAR1 (S831).

A mesoporous LaCoO

Based on the finite-time switching control method, the transition process of the vertical take-off and landing (VTOL) UAV is studied, the flight control of the take-off and climb sections. For the dynamic characteristics of the transition mode, a single constant system model can no longer meet the requirements, so it is modeled as a switching system characterized by multiple modalities. Based on the average dwell time method, sufficient conditions are given for stabilizing the longitudinal motion flight control system in a limited time. Simulation results show that the designed switching control law can make the VTOL UAV effectively and achieve smooth transition during the take-off and climbing phase of VOTL UAV.

This paper investigates the nonidentical parallel production line scheduling problem derived from an axle housing machining workshop of an axle manufacturer. The characteristics of axle housing machining lines are analyzed, and a nonidentical parallel line scheduling model with a jumping process operation (NPPLS-JP), which considers mixed model production, machine eligibility constraints, and fuzzy due dates, is established so as to minimize the makespan and earliness/tardiness penalty cost. While the physical structures of the parallel lines in the NPPLS-JP model are symmetric, the production capacities and process capabilities are asymmetric for different models. Different from the general parallel line scheduling problem, NPPLS-JP allows for a job to transfer to another production line to complete the subsequent operations (i.e., jumping process operations), and the transfer is unidirectional. The significance of the NPPLS-JP model is that it meets the demands of multivariety mixed model production and makes full use of the capacities of parallel production lines. Aiming to solve the NPPLS-JP problem, we propose a hybrid algorithm named the multi-objective grey wolf optimizer based on decomposition (MOGWO/D). This new algorithm combines the GWO with the multi-objective evolutionary algorithm based on decomposition (MOEA/D) to balance the exploration and exploitation abilities of the original MOEA/D. Furthermore, coding and decoding rules are developed according to the features of the NPPLS-JP problem. To evaluate the effectiveness of the proposed MOGWO/D algorithm, a set of instances with different job scales, job types, and production scenarios is designed, and the results are compared with those of three other famous multi-objective optimization algorithms. The experimental results show that the proposed MOGWO/D algorithm exhibits superiority in most instances.

In this research, the focus is on the adaptive fuzzy neural networks (NNs) control of the single-link flexible robot manipulator, which achieves accurate trajectory tracking and improves the speed of position tracking. Firstly, in order to establish a single-link flexible model, the lumped spring-mass method and Lagrangian equation are used. Secondly, a full-state feedback control is proposed. Aiming at achieving the control objective, the Lyapunov stability method proves that the closed-loop system is uniformly ultimately bounded. Finally, Numerical simulations are carried out to verify the performance of the fuzzy NNs control. Furthermore, the control performance is compared with the proportion derivative control.

The mechanism of H2-assisted NH3-selective catalytic reduction (SCR) over Ag/Al2O3 was systematically investigated by kinetic measurements and in situ diffuse reflectance infrared Fourier transform...

For the problem of motion state estimation of mobile target tracked by sensor nodes, the information-weighted Kalman consensus filter (IKCF) is introduced for sensor networks with switching communication topologies. In order to improve the dynamic performance of the IKCF, the low-pass consensus filtering algorithm is used to estimate the motion acceleration of the target. Moreover, an improved low-pass consensus filter is proposed to make the estimated motion accelerations converge to a smaller range. With low-pass consensus filtering for measured motion accelerations, the switched linear system of collective estimation errors of the IKCF is derived. Furthermore, it is proved that the switched linear system of collective estimation errors is globally uniformly asymptotically stable with a weighted $${l_2}$$-gain. Consequently, the conclusion is deduced that estimations of the target motion state can achieve consensus and converge to the target motion state within a bounded region as $$t \rightarrow \infty $$ under switching topologies. Finally, the effectiveness of the proposed approaches is illustrated by several illustrative examples.

Adsorption is an efficient method for atmospheric NOx abatement under ambient conditions; however, traditional adsorbents suffer from limited adsorption capacity and byproduct formation. Developing a low-cost material with high capacity for atmospheric NO2 elimination remains a challenge. Here, we synthesized a nanodispersed Mn3O4/γ-Al2O3 (Mn/Al) material that exhibits excellent ability to remove NO2. The 10 wt % Mn/Al sample showed the highest removal capacity, with 247.6 mgNO2/gMn/Al, which is superior to that of activated carbon (42.6 mgNO2/g). There were no byproducts produced when Mn/Al was tested with ppb-level NO2. The NO2 abatement mechanism with Mn/Al is different from physisorption or chemisorption. NO2 removal is mainly a catalytic process in air, during which surface hydroxyls and lattice oxygen are involved in the oxidation of NO2 to nitrate. In contrast, a chemical reaction between Mn3+ and NO2 is dominant in N2, where Mn3+ is converted into Mn4+ and NO2 is reduced to nitrite. Washing with deionized water is an effective and convenient method for the regeneration of saturated Mn/Al, and an 86% adsorption capacity was recovered after one washing. The results suggest that this low-cost Mn/Al material with easy preparation and regeneration is a promising candidate material for atmospheric NO2 elimination.

The sulfur tolerance of Ag/Al2O3 catalysts in H2-assisted C3H6-SCR was investigated by UV–vis, TPR, TPSR, DRIFTS-MS, and DFT calculations. Ag/Al2O3 with higher silver loadings exhibited better deNOx performance and sulfur tolerance, especially the 4% Ag/Al2O3 catalyst. UV–vis and H2-TPR revealed that highly dispersed Ag+ cations were predominant on 2% Ag/Al2O3, while more metallic Ag clusters with large sizes were present on the 4% Ag/Al2O3. After exposure to SO2, large amounts of sulfates were adsorbed on the Ag sites and Al sites of the Ag/Al2O3 surface. The sulfates were reduced to H2S and SO2 in a reducing atmosphere, while they showed little decomposition under real SCR reaction conditions. DRIFTS-MS experiments showed that sulfate species transferred rapidly between Ag sites and Al sites on the Ag/Al2O3 catalysts with higher amounts of Ag clusters. DFT calculations revealed that Ag1 cations show stronger affinity for sulfate species than Ag clusters, thus resulting in blockage by sulfates at the Ag-O-Al interface. Such blocking by sulfates suppressed the activation of C3H6 as well as the formation of -NCO species, and thus severely inhibited the deNOx performance of 2% Ag/Al2O3. In contrast, the rapid mobility of sulfate species on 4% Ag/Al2O3 made more active sites available for the formation of key intermediates of HC-SCR, finally contributing to its excellent sulfur tolerance.