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Catalytic ozonation is a non-selective mineralization technology of organic matter in water by using active free radicals generated by ozone degradation. Catalytic ozonation technology can be divided into homogeneous catalytic reactions using metal ions as catalysts and heterogeneous catalytic reactions using solid catalysts. Homogeneous catalytic ozonation technology has many problems, such as low mineralization rate, secondary pollution caused by the introduction of metal ions and low utilization efficiency of oxidants, which limit its practical application. Compared with homogeneous catalytic ozonation technology, heterogeneous catalytic ozonation technology has the advantages of easy recovery, lower cost of water treatment, higher activity and improved mineralization rate of organic matter. This overview classifies and describes catalysts for heterogeneous catalytic ozonation technology, including the different types of metal oxides, metal-free catalysts, and substrates used to immobilize catalysts. In addition, the heterogeneous catalytic ozonation process involved in the multiphase complex reaction process is discussed. The effects of different parameters on the performance of heterogeneous catalytic ozonation are also discussed. [ABSTRACT FROM AUTHOR]

(1) Background: For completely lower pole renal tumors, we compared the perioperative outcomes of robotic partial nephrectomy via transperitoneal and retroperitoneal approaches. (2) Methods: Complete lower pole renal tumors were defined as tumors that received 1 point for the "L" element of the R.E.N.A.L. and located at the lower pole of kidney. After confirming consistency in baseline characteristics, oncological and functional benefits were compared. Pentafecta achievement was used to represent the perioperative optimal outcome, followed by multivariate analysis of factors associated with the lack of pentafecta achievement. (3) Results: Among 151 patients identified, 116 (77%) underwent robotic partial nephrectomy via a transperitoneal approach and 35 (23%) via a retroperitoneal approach. Patients undergoing transperitoneal robotic partial nephrectomy experienced more blood loss than those undergoing retroperitoneal robotic partial nephrectomy (50 mL vs. 40 mL, p = 0.015). No significant differences were identified for operative time (120 min vs. 120 min), ischemia time (19 min vs. 20 min), positive surgical margins (0.0% vs. 2.86%), postoperative rate of complication (12.07% vs. 5.71%). No significant differences were identified in pathologic variables, eGFR decline in postoperative 12-month (3.9% vs. 5.4%) functional follow-up. Multivariate cox analysis showed that tumor size (OR: 0.523; 95% CI: 0.371–0.736; p < 0.001) alone was independently correlated to the achievement of pentafecta. (4) Conclusions: For completely lower pole renal tumors, transperitoneal and retroperitoneal robotic partial nephrectomy provide similar outcomes. These two surgical approaches remain feasible options for these cases. [ABSTRACT FROM AUTHOR]

Flame-retardant science and technology are sciences developed to prevent the occurrence of fire, meet the needs of social safety production, and protect people's lives and property. Rigid polyurethane (PU) is a polymer formed by the additional polymerization reaction of a molecule with two or more isocyanate functional groups with a polyol containing two or more reactive hydroxyl groups under a suitable catalyst and in an appropriate ratio. Rigid polyurethane foam (RPUF) is a foam-like material with a large contact area with oxygen when burning, resulting in rapid combustion. At the same time, RPUF produces a lot of toxic gases when burning and endangers human health. Improving the flame-retardant properties of RPUF is an important theme in flame-retardant science and technology. This review discusses the development of flame-retardant RPUF through the lens of bibliometrics. A total of 194 articles are analyzed, spanning from 1963 to 2021. We describe the development and focus of this theme at different stages. The various directions of this theme are discussed through keyword co-occurrence and clustering analysis. Finally, we provide reasonable perspectives about the future research direction of this theme based on the bibliometric results. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) has received increasing attention from researchers since it was first discovered on rough silver electrode surfaces in 1974 and has promising applications in life sciences, food safety, and environmental monitoring. The discovery of graphene has stirred considerable waves in the scientific community, attracting widespread attention in theoretical research and applications. Graphene exhibits the properties of a semi-metallic material and has also been found to have Raman enhancement effects such as in metals. At the same time, it quenches the fluorescence background and improves the ratio of a Raman signal to a fluorescence signal. However, graphene single-component substrates exhibit only limited SERS effects and are difficult to use for trace detection applications. The common SERS substrates based on noble metals such as Au and Ag can produce strong electromagnetic enhancement, which results in strong SERS signals from molecules adsorbed on the surface. However, these substrates are less stable and face the challenge of long-term use. The combination of noble metals and graphene to obtain composite structures was an effective solution to the problem of poor stability and sensitivity of SERS substrates. Therefore, graphene-based SERS has been a popular topic within the last decade. This review presents a statistically based analysis of graphene-based SERS using bibliometrics. Journal and category analysis were used to understand the historical progress of the topic. Geographical distribution was used to understand the contribution of different countries and institutions to the topic. In addition, this review describes the different directions under this topic based on keyword analysis and keyword co-occurrence. The studies on this topic do not show a significant divergence. The researchers' attention has gradually shifted from investigating materials science and chemistry to practical sensing applications. At the end of the review, we summarize the main contents of this topic. In addition, several perspectives are presented based on bibliometric analysis. [ABSTRACT FROM AUTHOR]

The clutch engagement process involves three phases known as open, slipping, and locked and takes a few seconds. The engagement control program runs in an embedded control unit, in which discretization may induce oscillation and even instability in the powertrain due to an improper scheduling period for the engagement control task. To properly select the scheduling period, a methodology for control–scheduling co-design during clutch engagement is proposed. Considering the transition of the friction state from slipping to being locked, the co-design framework consists of two steps. In the first step, a stability analysis is conducted for the slipping phase based on a linearized system model enveloping the driving and driven part of the clutch, feed-forward and feedback control loop together with a zero-order signal hold element. The critical period is determined according to pole locations, and factors influencing the critical period are investigated. In the second step, real-time hardware-in-the-loop experiments are carried out to inspect the dynamic response concerning the friction state transition. A sub-boundary within the stable region is found to guarantee the control performance to satisfy the engineering requirements. In general, the vehicle jerk and clutch frictional loss increase with the increase in the scheduling period. When the scheduling period is shorter than the critical period, the rate of increase is mild. However, once the scheduling period exceeds the critical period, the rate of increase becomes very high. [ABSTRACT FROM AUTHOR]

Multispeed transmissions are helpful for improvement of the economy and drivability of electric vehicles (EVs). In this paper, we propose a two-speed transmission based on dual planetary gear mechanism, in which shifts are realized by torque transfer between two brakes located on ring gears. To synthesize the dynamic and economic performances of the vehicle, a multiobjective optimization problem is constructed for gear ratio optimization and Pareto-optimal solutions of gear ratio combinations are obtained by Nondominated sorting genetic algorithm-II (NSGA-II). In particular, the minimum electric energy consumption of the EV is calculated with a fast Dynamic Programming (DP) in each iteration. Following this, a constant-output-torque control (COTC) scheme is adopted for the torque phase and inertia phase of gearshift process to ensure constant output torque on the wheel. To enhance transient responses, the feedforward–feedback controller structure is applied and a disturbance observer is integrated to improve robustness. Simulation results demonstrate that the two-speed transmission has much better performance in terms of acceleration time and energy economy compared to the fixed-ratio transmission, and the proposed gearshift control method is able to achieve fast and smooth gear shift robustly while maintaining constant output torque. [ABSTRACT FROM AUTHOR]

The bidirectional inverting buck-boost converter (BIBBC) has a simple structure and a wide voltage ratio. It can be used in the battery supercapacitor hybrid energy storage system (BSHESS) and the motor drive system. However, the traditional continuous conduction mode (CCM) BIBBC will have severe switching loss. The triangular current mode (TCM) BIBBC can reduce the switching loss, but it will increase core loss and filter capacitance. To solve these problems, this paper proposes a new zero voltage switching (ZVS) BIBBC using a coupled inductor. This ZVS BIBBC will provide ZVS conditions for both transistors whether in positive operation or negative operation. Meanwhile, this ZVS BIBBC has small core losses and filter capacitance, and can be used simply. Finally, experimental results obtained from these BIBBC experimental prototypes are presented to validate the soft-switching achieving and the efficiency improvement performance. Experimental results show that both transistors of the ZVS BIBBC achieve ZVS turn-on conditions. The efficiency of the ZVS BIBBC increased by up to 10 percent compared to the traditional CCM BIBBC at heave load, and by up to 1.5 percent compared to the TCM BIBBC at a light load. [ABSTRACT FROM AUTHOR]