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A diazirine-based four-armed cross-linker (4CNN) with a tetrahedron geometry is presented for efficient patterning of polymeric semiconductors by photo-induced carbene insertion. After blending of 4CNN with no more than 3 % (w/w), photo-patterning of p-, n-, and ambipolar semiconducting polymers with side alkyl chains was achieved; regular patterns with size as small as 5 μm were prepared with appropriate photomasks after 365 nm irradiation for just 40 s. The interchain packing order and the thin film morphology were nearly unaltered after the cross-linking and the semiconducting properties of the patterned thin films were mostly retained. A complementary-like inverter with a gain value of 112 was constructed easily by two steps of photo-patterning of the p-type and n-type semiconducting polymers. The results show that 4CNN is a new generation of cross-linker for the photo-patterning of polymeric semiconductors for all-solution-processible flexible electronic devices.

A fluorescent probe based on the functionalized carbon quantum dots (CQDs-OPD) was successfully synthesized for selective and sensitive detection of Cu2+. Using O-phenylenediamine (OPD) as the carbon resource and N,N-dimethylformamide (DMF) as the solvent, the CQDs-OPD was prepared by the hydrothermal method. The fluorescence mechanism of CQDs-OPD was studied by the intercept method. Furthermore, the probe was characterized by TEM, UV–Vis, FT-IR and Zeta potentiometric analysis, the fluorescent probe exhibits a good fluorescence properties and stability. The prepared ratio-fluorescent probe shows a good linear range from 0 to 25 μmol/L with a lower LOD of 40 nmol/L. Moreover, the probe also has been successfully applied to the detection of Cu2+ in the real samples with the recovery rate of 96.92–97.80% and the RSD of less than 2.0%.

The transmission capacity of gas pipeline networks should be calculated and allocated to deal with the capacity booking with shippers. Technical capacities, which depend on the gas flow distribution at routes or interchange points, are calculated with a multiobjective optimization model and form a Pareto solution set in the entry/exit or point-to-point regime. Then, the commercial capacities, which can be directly applied in capacity booking, are calculated with single-objective optimization models that are transformed from the above multiobjective model based on three allocation rules and the demand of shippers. Next, peak-shaving capacities, which are daily oversupply or overdelivery amounts at inlets or deliveries, are calculated with two-stage transient optimization models. Considering the hydraulic process of a pipeline network and operating schemes of compressor stations, all the above models are mixed-integer nonlinear programming problems (MINLPs). Finally, a case study is made to demonstrate the ability of the models.

To cope with the global food shortage and insect pest, there is an urgent need to discover new pesticides with novel modes of actions. Ryanodine receptor (RyR) insecticides showed great promise in ...

In this paper, a novel systematic and integrated methodology to assess gas supply reliability is proposed based on the Monte Carlo method, statistical analysis, mathematical-probabilistic analysis, and hydraulic simulation. The method proposed has two stages. In the first stage, typical scenarios are determined. In the second stage, hydraulic simulation is conducted to calculate the flow rate in each typical scenario. The result of the gas pipeline system calculated is the average gas supply reliability in each typical scenario. To verify the feasibility, the method proposed is applied for a real natural gas pipelines network system. The comparison of the results calculated and the actual gas supply reliability based on the filed data in the evaluation period suggests the assessment results of the method proposed agree well with the filed data. Besides, the effect of different components on gas supply reliability is investigated, and the most critical component is identified. For example, the 48th unit is the most critical component for the SH terminal station, while the 119th typical scenario results in the most severe consequence which causes the loss of 175.61 × 104 m3 gas when the 119th scenario happens. This paper provides a set of scientific and reasonable gas supply reliability indexes which can evaluate the gas supply reliability from two dimensions of quantity and time.

Real-time flow estimation plays a vital role in multi-product pipeline operations, and the accuracy of real-time flow estimation is affected by noise interference and instrument accuracy and cannot be performed by direct observation of flow meter. Pipeline flow models based on the first principle method are established and employed as soft sensors of pipeline real-time flow rate. However, these models are validated by the controlled experimental pipeline, which may be ineffective regarding actual pipelines with uncertain physical parameters. In this paper, a novel approach integrating data-driven and model-driven method is proposed to estimate the flow rate of petroleum products on-line. The difference between the theoretical model and actual state of a pipeline is accounted for by the friction coefficient, and on-line calibration is achieved by solving multi-objective optimisation problems with asynchronous operation data. The flow state of the pipeline is obtained in real time by the particle filter when new pressure observations with noise become available. The estimation performance of local pressure mutation points is improved by adopting the recurrent nonlinear autoregressive neural network modelling blue of the data-driven method. The effectiveness of the proposed method is evaluated blue by examining actual data of the pipeline over a period of time. The prediction results of some other model-driven and data-driven methods are also compared to blue that of the proposed method. The results blue indicate that the proposed method improves the accuracy and reliability of the product flow rate estimations even under unforeseen operation conditions.

In recent years, with the goal of “carbon peaking and carbon neutralization”, the CO2 flooding technology in carbon capture, utilization, and storage (CCUs) has been paid great attention to the oil fields. However, the CO2 flooding of crude oil may produce foams in the oil and gas separation process. In addition, the precipitation of wax components in crude oil might enhance the stability characteristics of these foams and lower the separator’s efficiency. Based on a crude oil depressurization foaming device, the influence of wax crystals on the bursting of oil foam was studied using simulated oil, and the microstructure of the wax crystal and foam liquid film was observed using freeze-etching and microscopic observation. In addition, the gas–liquid interface model of the wax oil was established by a molecular dynamics (MD) simulation to analyze the influence mechanism of wax crystals on foam drainage and gas diffusion among foams in the microlayer. The results show that the precipitation of wax crystals overall reduces the rate of defoaming and drainage and increases the grain diameter of the foam. The formation and growth of the wax crystal-shaped network impede the flow of liquid in the drainage channel and stabilize the foam. Moreover, it impedes the diffusion of CO2 among foams, inhibiting the bursting of the foams. The results of the combined experiments and MD simulation verify the accuracy and applicability of the molecular model, which further clarifies the effect of wax crystals on foam stability and its mechanism of action on foam film. These findings are a benchmark for the enhancement of defoaming and separation efficiency and a theoretical framework for future study and modeling.

An innovative molecular imprinted polymer based on KH-570 modified SiO2-coated cadmium telluride quantum dots was prepared as fluorescence sensor for sulfadimidine (SM2) sensitive and selective detection. The quantum dots were firstly encapsulated in silica by sol–gel process, and then the double bond was modified on the surface of silica with KH-570. Finally, the molecular imprinted layer was synthesized on the surface of silica by template molecule, methacrylic acid (MAA) and ethylene glycol dimethyl acrylate. The fluorescence sensors showed good structure when characterized by SEM. Besides, the fluorescence sensors showed a good linear range from 10 to 80 μmol.L−1 with a lower LOD of 0.42 μmol.L−1. These sensors were successfully applied to detect SM2 in the water samples with a recovery rate from 91.6% to 97.8% and the relative standard deviation less than 2.5%, indicating that fluorescence sensors have the potential application in the detection of real samples.

In this paper, a new methodology is proposed to realize real-time unsteady flow estimation for a multi-product pipeline system. Integrating transient flow model, adaptive control theory, and adaptive filter, this method is developed to solve the contradiction between the efficiency and accuracy in traditional model-based methods. In terms of improving computational efficiency, the linear flow model based on frequency response and difference transforming is established to replace the traditional nonlinear flow model for transient flow state estimation. To reduce the deviation between actual observations and linear model estimates, we first introduce a model-free adaptive control method as linear compensation of the reduced order unsteady flow state model. To overcome the interference of observation noise, the Kalman filter method is applied to the modified state space model to obtain the one-step-ahead transient flow estimation. The proposed method is applied to the transient flow state estimation of a multi-product pipeline system and compared with the model-based method and two data-driven methods. The proposed method can reduce the deviation of transient flow estimation between the reduced order linear model and the traditional nonlinear model to less than 0.5% under unforeseen conditions and shows strong robustness to noise interference and parameter drift.

Background. Autogenous tooth transplantation is a reliable method for repairing missing teeth. Although it recently became a recognized and feasible treatment method in dentistry, the long-term efficacy of root canal therapy (RCT) has not been well confirmed. This study is aimed at determining whether RCT has a good effect on the success rate of teeth with complete roots in autogenous tooth transplantation. Materials and Methods. Data were collected from the Korea University Guro Hospital. Data of patients who underwent autogenous tooth transplantation within 9 years were collected. We selected 29 teeth with complete roots as the research subjects in our study. None of the patients had any systemic diseases. All cases in this study were obtained with patient permission. Results. According to the tooth vitality test, the autogenous teeth tested negative in dental pulp test and function. Nine of the 29 teeth with autogenous tooth transplantation were treated with RCT and survived throughout the observation period. However, 20 autogenous teeth were not treated with RCT, and eight of them did not survive. All statistical analyses were performed using IBM SPSS 20.0. The null hypothesis was rejected ( p < 0.05 ). Conclusion. For complete root teeth, the success rate after autogenous tooth transplantation after RCT is higher than that of teeth not treated with RCT.

This paper proposes a digital twin solution for unsteady flow state estimation in a pumping station. Digital twin is expected to accurately estimate the real-time hydraulic parameters of blind spots of the pumping station system even under some adverse conditions including the interference of observation noise and model parameters drift. To solve these challenges, a digital twin framework integrating the model-driven method, control theory and data-driven method is presented. In this framework, an unsteady flow state estimation method combining frequency domain analysis and generalized predictive control theory is developed for the first time, which is superior to traditional time-domain numerical discrete methods in terms of computational efficiency and anti-noise interference. In the model parameter calibration process, the novelty concerns modeling of the optimization problem considering the dynamic operation control of the station and unsteady flow of pipelines. And this process is accomplished through the comprehensive application of the model-free adaptive control algorithm, the transient flow model and the particle swarm optimization algorithm. This work is applied to a pumping station in a product pipeline to verify its effectiveness in estimating the transient flow state of data blind spots and map the dynamic operation behavior under the interference of colored noise and parameter drift.

To cope with the global food shortage and insect pest, there is an urgent need to discover new pesticides with novel modes of actions. Ryanodine receptor (RyR) insecticides showed great promise in integrated pest management. Herein, we report the synthesis of novel anthranilic diamide derivatives incorporating pyrrole moieties targeting at insect RyRs. The structures were confirmed by

This paper addresses how to optimize detailed schedules of a multiproduct pipeline network. A continuous-time mixed integer linear programming (MILP) formulation is developed to seek the minimum makespan of transportation tasks. Operation constraints about sequence of products, size of single-product batches, flow rate of delivery and injection operations, pumping rate of pipeline segments, batch tracking, conditions of implementing injection or delivery operations, inventory management of stations and consumer markets’ demand are all satisfied. The MILP formulation is illustrated by three pipeline networks. Results show the proposed MILP model has a better performance than previous works.

The fluorescence mechanism of dual-emission carbon quantum dots (DCQDs) is investigated by the improved intercept method, of which the DCQDs with high quantum yield are synthesized by hydrothermal method by using the precursor of sulfadiazine. The research of the morphology, chemical properties and fluorescence properties on DCQDs, shows that DCQDs have graphene-like structure and well-resolved lattice fringes, and that DCQDs fluorescence emission as well intensity has reversibility between acid and alkaline. Based on the ultraviolet absorption spectrum (UV–vis) of the DCQDs, the band gap of DCQDs is estimated by the improved intercept method. Then, the change law of DCQDs emission wavelength at different excitation wavelengths is studied by using the estimated band gap. It is found that the improved intercept method is well consisted with the emission change law of DCQDs at different excitation wavelengths. In addition, the influence of different concentration of Fe3+ on the estimated band gap of DCQDs shows that the Fe3+ has big influence on the band gap of 3.99 eV and 3.06 eV but almost no effect on band gap of 4.93 eV and 3.67 eV. It indicates that the quenching of Fe3+ to DCQDs may be due to the band gap caused by surface defect is changed by Fe3+. Also, DCQDs are used as probe to detect Fe3+ and used as spray ink. Thereby, the improved intercept method may provide a new direction for researching the fluorescence mechanism of carbon quantum dots.

Waxy crude oil exhibits shear-dependent and time-dependent thixotropic behavior below the threshold temperature. Various models have been proposed to describe this type of behavior in previous lite...

When several kinds of crude oil need to be transported, the batch pipelining is a better choice than the “single-pipeline-single-oil” and blending pipelining due to its advantages. In the batch pipelining process, to avoid the frequent operations on the pumps and control valves, the flow rate is generally inconstant in practice. All previous studies simplify the flow rate distribution as a constant one, which largely deviates from the engineering practice. Focused on this point, based on the features of the batch pipelining in practice, the gradient-type flow rate distribution model and corresponding calculation approach are proposed in this paper. The accuracy of this model and corresponding calculation approach are verified by the field data, and it indicates that the accuracy of numerical results can meet the engineering requirement. Further, the thermal characteristics of the batch pipelining are found by numerical simulation and the further analysis is carried out to make these characteristics more convincing. Finally, the shortcoming of the step-type flow rate distribution with simple expression is pointed out. It is found that the adoption of the step-type flow rate distribution in the simulation would introduce a prominent deviation when the change period of flow rate is relatively long. To overcome this shortcoming, the proposed gradient-type flow rate distribution, whose accuracy is higher, is an alternative method.

In this paper, a double-pipe heat exchanger with a series of corrugated tubes as inner tubes is studied for the adequate cooling of thermal-hydrolyzed sludge. A numerical model, built on the Spalart-Allmaras model, is validated to have the ability for characterizing the flow and heat transfer performance of sludge. The influencing factors, including the flow parameters of the sludge and cooling water, and the geometric configurations of the corrugated tube are parametrically investigated. The ratio of Nusselt number (Nu/Nu0), the coefficient of flow resistance (f/f0) of the sludge, the synthesis factor of performance (η) and the ratio of the heat transfer increase over the pump power increase ( ζ ) are used as the performance assessment indexes. The results show that increasing Resludge can negatively affect η and η tends to be stable when Rewater is higher than 1.2 × 104. Decreasing S/D and increasing H/D result in a higher ratio of flow resistance f/f0 and a higher ratio of Nu/Nu0. The corrugation height (H) shows a larger effect than the corrugation length (S). In practical applications, the optimal flow rates of the sludge for the studied corrugated tubes are recommended to be within the range of 1.2–1.5 m/s.

CO2 flooding crude oil may generate abundant foams in oil field separators after depressurization. A large amount of foams occupies most of the space in a separator and spends much time to burst, which, in turn, reduces the separation efficiency of the separator. Moreover, the incomplete gas-liquid separation will cause corrosion in the downstream pipeline, and damage both the pump and the compressor. Based on the self-development crude oil depressurization foaming device and the CO2 flooding crude oil, this paper studies the evolution of foam and analyzes the function mechanism of asphaltene and wax crystal on defoaming and drainage of crude oil quantitatively. The experimental results show a law that the rate of defoaming and drainage increase at the initial stage and then decrease, which is available for different crude oils. So, the paper proposes a kinetics model of the defoaming and drainage based on the three-degree polynomial function innovatively, which not only describes the evolution of foam volume, but also indicates the change of foam drainage rate. Meanwhile, the experiments found that asphaltene promoted the stability of foams by being adsorbed on foam film in the process of liquid drainage. Wax crystal reduced the fluidity of drainage, which decreased the defoaming and discharging rate. But the wax crystal with specific structures reduced the stability of foams. It is significant to explore the foaming and defoaming mechanism of crude oil for providing references for the improvement of separator efficiency and the development of separation technology.

The effect of nonionic surfactant (Tween 80) concentration on the evolution of drop size distributions (DSDs) of oil/water dispersion in a stirred tank was investigated experimentally and numerically. It was found that as the surfactant concentration increases, the mean droplet size decreases, the number density of small droplets increases and the dispersion stability is enhanced. It could be attributed to the augmentation of the breakage frequency caused by a dramatic reduction of interfacial tension and the suppression of the coalescence efficiency by an immobilized interface. When applying population balance equation (PBE) to surfactant dispersions, the effect of surfactant concentration was characterized by its influence on both breakage and coalescence process. The combined effect of surfactant molecules, drop size, and the number density of droplets on the turbulence intensity was considered in the breakage model. Models of coalescence time that consider partially mobile and immobile interfaces were employed to describe the film drainage at surfactant concentrations below and above CMC (critical micelle concentration) respectively. The effect of surfactant concentration on the critical film thickness was probed by adjusting the Hamaker constant and measuring the interfacial tension, while its influence on the coalescence efficiency was investigated by further balancing the contact and coalescence time. Both the predicted Sauter mean diameter and cumulative DSD agree with the experimentally measured values at different surfactant concentrations, while the discrepancies that exist could be due to the underestimation of coalescence rate between small droplets.

Recently, spinel ferrites have attracted much attention due to their various redox states, great electrochemical stability, and pseudocapacitive behavior. Herein, NiFe 2 O 4 /MoS 2 composite material with excellent electrochemical properties was smart-designed and successfully synthesized via a facile solution reaction and freeze-dried process for the first time. The composite combines the advantages of both MoS 2 nanosheets and NiFe 2 O 4 nanoparticles, showing enhanced capacitive performance than MoS 2 nanosheets and NiFe 2 O 4 nanoparticles and surpassed some of the previously reported materials. A maximum specific capacitance (506 F/g at 1 A/g) of NiFe 2 O 4 /MoS 2 composite was obtained, and the electrode can kept over 90.7% (at 5 A/g) of capacitance after 3000 cycles. The excellent electrochemical performance is attributed to the synergistic effect of MoS 2 nanosheets and NiFe 2 O 4 nanoparticles. Moreover, this complex material could be used in other advanced energy storage and conversion systems, such as Li-ion batteries, Li-air batteries, Na-ion hybrid capacitors, hydrogen evolution reaction catalysts, etc.

A multiproduct pipeline is an economical way for transporting several products from a single source to multiple delivery stations over a long distance. This paper addresses how to optimize detailed schedules of a multiproduct pipeline. A discrete-time mixed integer linear programming model is developed, which adopts a novel objective function to seek the minimum summation of pumping rate variations in every pipeline segment along a pipeline during a scheduling horizon. The feasibility of the new objective function is demonstrated in theory. A conclusion is drawn that the more stable pumping rate of a pipeline segment is, the lower frictional loss for pumping products is. Besides operational constraints, two sets of special constraints are introduced into the model for improving the operability and practicability of detailed schedules. One is the stopping and running duration limitations of injection operations and another one is the flow rate stability requirements of injection and delivery operations. The proposed MILP model is successfully tested on two real world multiproduct pipelines using CPLEX as solver.

For the purpose of investigating the effect of dispersed phase on turbulence characteristics, both CFD simulation and experiments from particle image velocimetry (PIV) on flow field at different dilute liquid-liquid dispersion are performed. CFD simulation is established by coupling mixture model and empirical mean drop size for two phase mixing. Turbulent kinetic energy (TKE) and energy dissipations rate (EDR) are discussed as key parameters. With the addition of dispersed phase, CFD results indicate that TKE decrease when EDR increase in impeller region and both decrease in circulation region; while experimental results shows both TKE and EDR increase in the full flow range. Trend reflected from CFD results is supposed to be the suppression on velocities fluctuation by enlarged density and viscosity of the dispersed phase, and the enhancement of energy dissipation rate by viscosity. Further work concerning the dynamics of drop distribution evolution (coupling Population Balance Equations, PBE) in CFD simulation is particularly demanded, where the effect of drop behaviors including random motion, breakage and coalescence on turbulence intensity could be discussed.

Due to new mechanism of action and ecofriendly characteristics, dicarboxamide insecticides have attracted more and more attentions in modern pest management. A series of 20 dual chiral N-cyano sulfilimines containing two centers (carbon and sulfur) were designed and synthesized. All title compounds were determined by 1H NMR, high-resolution mass spectrometry (HRMS) and optical polarimeter. The preliminary results indicated that some of them exhibited favourable insecticidal activities against oriental armyworm (Pseudaletia separata Walker). These isomers exhibited different impact on activity following the sequence as (Sc, Ss) ≥ (Sc, Rs), and the rule of title compounds’ activity against oriental armyworm was 3-CF3 ≥ 2 CH3 4 Cl >2, 3, 4-trifluro in the anilide moiety. The results indicated that these groups such as 3-CF3, 2 CH3 4 Cl or 2, 3, 4-trifluro were inefficient to replace heptafluoroisopropyl group for high larvicidal activity, which provided some guidance for the further modifications of sulfiliminyl dicarboxamides.