Conventional Operation Method Research Articles

Optimizing the separation process for improved zirconia molding through liquid crystal display 3D printing

Mask stereolithography 3D printing for zirconia ceramics has attracted increasing attention in the industrial manufacturing due to their advantages of complex shapes, precisely controlled internal structures and fine surface effects. However, high refractive index and expensive equipment cost have always affected its development. Herein, we combine liquid crystal display (LCD) light curing 3D printing with zirconia molding, which is free from environmental and price limitations. In the conventional method of operation, the cured layer is bonded to the bottom and cannot be manufactured. We put forward a strategy for optimizing separation process and investigate the mechanism of the separation process in depth for high-quality zirconia ceramics LCD 3D printing. The results show that the controlled adjustment of the surface free energy can achieve a great reduction in the separation force, which enabled the successful printing of zirconia ceramics based on LCD. The effect of physical properties of the separation membrane on the separation process was studied and the solid content and 3D printing parameters of ceramic paste were optimized. When the solid content is 72.5 wt%, high quality zirconia ceramic parts with flexural strength of 255 MPa and relative density of 98.1 % can be obtained. This work provides new ideas for the convenient customization of zirconia ceramics in many fields.

Adaptive identification method of new energy grid operation risk based on linear decision function

The current conventional risk identification method of new energy grid operation mainly achieves risk identification by mining equipment status information, which leads to poor identification effect due to the lack of effective extraction of abnormal data features. In this regard, a linear decision function-based adaptive risk identification method for new energy grid operation is proposed. The data flow model is constructed by combining the linear decision function, and the features of interval abnormal data and fluctuating abnormal data are extracted. A sliding window model is constructed, and the unsupervised model is used to realize the effective update of new energy grid operation data. In the experiments, the proposed method is verified for recognition accuracy. The experimental results show that when the proposed method is used to identify the risk of grid operation, the effective data mis-deletion rate of the algorithm is low and has a more desirable identification effect.

A Hybrid Magneto‐Optic Capacitive Memory with Picosecond Writing Time

AbstractThe long‐term future of information storage requires the use of sustainable nanomaterials in architectures operating at high frequencies. Interfaces can play a key role in this pursuit via emergent functionalities that break out from conventional operation methods. Here, spin‐filtering effects and photocurrents are combined at metal‐molecular‐oxide junctions in a hybrid magneto‐capacitive memory. Light exposure of metal‐fullerene‐metal oxide devices results in spin‐polarized charge trapping and the formation of a magnetic interface. Because the magnetism is generated by a photocurrent, the writing time is determined by exciton formation and splitting, electron hopping, and spin‐dependent trapping. Transient absorption spectroscopy measurements show changes in the electronic states as a function of the magnetic history of the device within picoseconds of the optical pumping. The stored information is read using time‐resolved scanning magneto optic Kerr effect measurements during microwave irradiation. The emergence of a magnetic interface in the picosecond timescale opens new paths of research to design hybrid magneto‐optic structures operating at high frequencies for sensing, computing, and information storage.

Multi-objective optimization of operation strategy in snow melting system for airfield runway using genetic algorithm: A case study in Beijing Daxing International Airport

A hydronic snow melting pavement system is an efficient and sustainable snow removal approach. However, the conventional operation method remained unclear and usually led to a waste of energy. This study developed a thermal-economic model to assess this system's economic cost and snow melting effect. The multi-objective optimization (MOO) model and genetic algorithm (GA) were adopted to optimize the operation strategy, which includes fluid temperature (FT) and idling duration (ID). The accuracy of the MOO model was verified by a convergence study. The optimal results were organized in nomograms and implemented at Beijing Daxing International Airport. The results showed that the tournament selection method performs better in MOO solving. The optimal results indicated that it would obtain a better effect to balance the economic benefit and snow melting effect by adjusting FT than ID. And the MOO model can export the appropriate strategy in response to various snowfall conditions. Specifically, the optimal strategy implementation in the case study improved the snow-free duration ratio by 126% and saved the economic cost by 7% compared to the conventional strategies. The investigation provided an alternative operation strategy to minimize the energy cost for this system while ensuring the snow melting effect.

A Linear-Active-Disturbance-Rejection-Based Vertical Takeoff and Acceleration Strategy with Simplified Vehicle Operations for Electric Vertical Takeoff and Landing Vehicles

A practical vertical takeoff and acceleration strategy is developed for manned electric vertical takeoff and landing vehicles, with a simple vehicle operation principle defined. Firstly, a 6-DOF model is established for 120 kg reduced-scale protype electric vertical takeoff and landing vehicles, with its physical control principles illustrated. Then, a simple vehicle operation method is defined for the vehicle, where the conventional operation method for fixed-wings and helicopters is considered for a friendly stick response definition for pilots with different backgrounds. The defined simple vehicle operation principles are realized by a control architecture with a linear-active-disturbance-rejection-control-based inner loop stability augmentation system and an airspeed-based mode selection outer loop. This system is then used to perform a four-stage vertical takeoff and acceleration strategy, which targets at a smooth and safe transition. The Monte Carlo simulation results and the strategy simulations prove that the proposed strategy, which achieves the design target perfectly, can be easily performed with the developed simple vehicle operation system, and that it has sufficient robustness performance to reject at least 20% of the model’s uncertainties.

Sensitivity Model-Based Optimal Decentralized Dispatching Strategy of Multi-Terminal DC Links for the Integration of Distributed Generations in Distribution Networks

This study proposes a novel decentralized operation strategy for a multi-terminal direct current (MTDC) link system to control the power flow between interconnected distribution networks. The proposed strategy is divided into two stages. First, by applying a curve-/surface-fitting technique to the network topology data, the formulas for the voltage and total line losses in the network are derived. Subsequently, the active/reactive power set-points of the MTDC link are optimized to minimize the network losses and balance the injected power from the upstream grid. The optimization model with a quadratically constrained quadratic problem is relaxed as a second-order constrained programming model using the proposed substitution process. The proposed strategy is implemented solely based on the information at the point of common coupling of the MTDC link and does not require the acquisition of any real-time data related to the distributed generator output and load demand. The effectiveness of the proposed method is verified by comparing it with a conventional centralized operation method using modified IEEE-33 test networks.

Establishment and Evaluation of a Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Pseudomonas fluorescens in Raw Milk.

Raw milk is susceptible to microbial contamination during transportation and storage. Pseudomonas fluorescens producing heat-resistant enzymes have become the most common and harmful psychrophilic microorganisms in the cold chain logistics of raw milk. To rapidly detect P. fluorescens in raw milk, the protease gene aprX was selected as a detection target to construct a set of primers with strong specificity, and a loop-mediated isothermal amplification (LAMP) assay was established. The detection thresholds of the LAMP assay for pure cultured P. fluorescens and pasteurized milk were 2.57 × 102 and 3 × 102 CFU/mL, respectively. It had the advantages over conventional method of low detection threshold, strong specificity, rapid detection, and simple operation. This LAMP assay can be used for online monitoring and on-site detection of P. fluorescens in raw milk to guarantee the quality and safety of dairy products.

Microvascular myocutaneous and cutaneous free flap reconstruction in patients with terminal esophagostomy after complicated oncological esophagus resection

Summary Background Persisting anastomotic leakage after oncological esophagectomy is a severe problem associated with high mortality and morbidity. Unfortunately, treatment options with promising results are scarce, especially when conventional operative and endoscopic methods have failed. Due to limitation of oral intake and the need for artificial nutrition, quality of life (QOL) is reduced. Microvascular myocutaneous and cutaneous free flap (MFF) reconstruction could be a promising alternative. Methods This retrospective case series presents 7 patients treated between March 2017 and November 2020 at our surgical department, with persisting postoperative anastomotic leakage without further feasible treatment options. All patients received anastomotic MFF reconstruction; used flaps and important intraoperative factors like microvascular anastomosis were evaluated. Complications and patient contentment was assessed. Results The included 7 male patients had median age of 65.15 years (range: 48–75). MFF function was adequate in 6/7 patients, one flap necrosis was encountered. Whereas 5 patients initially had good results, surgical revision was performed in 1 patient to ensure graft function. Postoperative complications appeared in 6/7 patients. Mean duration of inpatient care was 63 days (range: 24–156). At the time of evaluation, 1 patient has died of his malignant disease. No more additional nutrition was needed in 3/6 patients with adequate graft function. Most patients reported improved QOL after MFF. Conclusion MFF free flap can be an alternative treatment option for patients with terminal esophagostomy after complicated oncological esophagus resection without further treatment options. The renewed ability of oral food intake results in a significant improvement of QOL.

Construction and Application of Reservoir Flood Control Operation Rules Using the Decision Tree Algorithm

Current conventional and optimal reservoir flood control operation methods insufficiently utilize historical reservoir operation data, which include rainfall, runoff generation, and inflow from the watershed, as well as the operational experience of decision makers over many years. Therefore, this study proposed and evaluated a new method for extracting reservoir flood control operation rules from historical operation data using the C4.5 algorithm. Thus, in this paper, the C4.5 algorithm is first introduced; then, the generation of the flood control operation dataset, the construction of decision tree-based (DT-based) rules, and the subsequent design of a real-time operating scheme are detailed. A case study of the Rizhao Reservoir is then employed to demonstrate the feasibility and even superiority of the operating scheme formulated using DT-based rules. Compared with previously proposed conventional and optimal reservoir operation methods, the DT-based method has the advantages of strong and convenient adaptability, enabling decision makers to effectively guide real-time reservoir operation.

662 MICROVASCULAR MYOCUTANEOUS AND CUTANEOUS FREE FLAP RECONSTRUCTION FOR PATIENTS WITH TERMINAL ESOPHAGOSTOMY AFTER COMPLICATED ONCOLOGICAL ESOPHAGUS RESECTION

Abstract Persisting anastomotic leak after oncological esophagectomy is a severe problem associated with high mortality and morbidity. Unfortunately, treatment options with promising results are scarce especially when conventional operative and endoscopic methods have failed. Due to limitation of oral intake and need for artificial nutrition quality of life is reduced. Microvascular myocutaneous and cutaneous free flap (MFF) reconstruction could be a promising alternative. Methods This retrospective cohort study presents seven patients treated between March 2017 and November 2020 at our surgical department, with terminal esophagostomy after complicated oncological esophagus resection without further feasible treatment options. All Patients received anastomotic MFF reconstruction. We have examined postoperative outcomes, complications according to Clavien-Dindo-Classification and patient contentment with a questionnaire. Additionally, we described important procedure related facts. Results The included seven male patients had median age of 65.15 years (range: 48–75). MFF function was adequate in six out of seven patients, graft rejection appeared in one patient. Five patients initially had good results, surgical revision was performed in one patient to ensure graft function. Postoperative complications appeared in 6/7 patients (Table 1). Mean duration of inpatient care was 63 days (Range: 24–156). At time of evaluation, one patient has died cancer related. No more additional nutrition was needed in 3/6 patients with adequate graft function. The majority of patients reported an improved quality of life compared to preoperatively. Conclusion MFF free flap can be a safe and feasible treatment option for patients with terminal esophagostomy after complicated oncological esophagus resection without further treatment options or in patients with complicated postoperative course with complex combined defects. The renewed ability of oral food intake results in a significant improvement of quality of life for the patients. No procedure related mortality was observed. Number of patients with regained ability of oral intake is encouraging.

Minimally invasive plate osteosynthesis in midshaft clavicular fracture in adults

Background Clavicle fractures are common injuries in adults, accounting for 5–12% of all fractures and 44% of all shoulder fractures. Fracture of the middle third is the most common fracture in both children and adults. It is ∼80% of clavicle fractures; proximal and distal segments are secured by ligamentous and muscular attachments. Poor outcomes from conservative treatment, including nonunion, malunion, or shortening of the clavicle in displaced or comminuted fractures, have prompted a shift in treatment to surgery. There has been a trend toward operative treatment of clavicle midshaft fractures. There are various methods for treating clavicle midshaft fractures, such as intramedullary K-wires or elastic stable intramedullary nailing and plate fixation. Minimally invasive percutaneous plate osteosynthesis technique may be a good alternative as it has been proven in other long bones. Objective This study is performed to address the technique of percutaneous plating and to evaluate the radiographic and clinical outcomes in midshaft fractures of the clavicle in adults treated with minimally invasive plate osteosynthesis (MIPO). Patients and methods From December 2015 to November 2017, this prospective case series study was done at Al Azhar University Hospitals. In our study, we present the outcomes of 17 patients (12 men and five women) with acute midshaft clavicular fractures who were treated with the MIPO technique with 3.5-mm superior reconstruction plates. The patients had a mean age of 27.76 years (range, 16–45 years). The left arm was affected in nine patients the right arm in eight patients. The fractures were classified using the Robinson classification system: 10 were type 2B1 and seven were type 2B2. Results Fracture union was obtained in all patients at a mean of 11.35±1.90 weeks (range, 8–15 weeks). No delayed unions or nonunions were observed. There were no major complications such as infections, plate breakages, or neurovascular injuries. All of the patients obtained satisfactory shoulder functions. The mean Constant score was 97.47±2.45 (range, 93–100), and the mean Disability of the Arm, Shoulder, and Hand score was 1.29±1.93 (range, 0–5) at the last control visit. Conclusion This study demonstrated that the MIPO procedure that uses superior 3.5-mm reconstruction plates for midshaft clavicular fractures can be a reproducible procedure and an alternative to conventional operative methods. In addition, satisfactory clinical and radiologic outcomes were obtained without serious complications. This technique can provide excellent biological healing and optimal stabilization strength. Level of evidence Level IV, case series, treatment study.

Multi-Microgrid-Based Operation of Active Distribution Networks Considering Demand Response Programs

In a novel approach, this paper investigates the effect of demand response (DR) programs simultaneous with the multi-microgrid-based operation of active distribution networks. In the proposed model, the possibility of microgrid construction is evaluated through technical indices such as supply-adequacy, efficiency, voltage profile, and reliability as well as DR transaction costs. The multi-objective optimization problem is solved by a powerful method named non-dominated genetic algorithm-II (NSGA-II). Due to the probabilistic nature of renewable energy sources, loads, and energy prices, these are modeled using their probability density functions by Monte Carlo simulation algorithm. Also, the backward–forward load flow method is employed for obtaining the objective function parameters. The results of the proposed model are compared with the conventional operation method in various scenarios by implementing it on IEEE 69-bus test distribution system.

Modeling and optimization for the smart operation of a central chilled water system in a high-rise building

Besides meeting the cooling demands of each terminal space in a high-rise building, the smart operation of a central chilled water system is also aiming at saving more electricity. Hence, it is the key issue to distribute proper amount of chilled water to each room according to its cooling load variations, i.e. achieve hydraulic balance in the chilled water network. To save electricity consumption of both chillers and circulation pumps in operation, in this paper, a supervisory optimization model is proposed for a general chilled water system. An improved node method is also presented to simulate the hydraulic behavior of the general chilled water pipe network, which is particularly adapted for a high-rise building with faster computation speed and fine accuracy. Then the proposed model is validated in a real high-rise hotel in Shanghai. In the case study, comparing with conventional operation method (On/Off or PID control), the proposed smart operation method can save 15.4-29.3% of electricity for the chilled water system in the typical days of cooling season.

Extraction and application of energy storage operation chart in Yangtze River cascade reservoirs

Abstract Reservoir operation charts have been widely researched and applied to reservoir operation. However, these achievements are generally used for a single reservoir and have rarely been applied to cascade reservoirs. Considering the requirements of flood control and water supply, this paper studied the extraction and application of energy storage operation chart (ESOC) for cascade reservoirs. Steps in the methodology mainly include: (1) model building of cascade reservoirs operation optimization (CROO), (2) extracting ESOC based on discriminant coefficient method (DCM) and CROO model, (3) simulation operation of ESOC based on DCM, (4) choosing the optimal ESOC and verifying its efficiency through the results. Cascade reservoirs in the Yangtze River of China were selected for a case study. Compared with the conventional operation method, the simulation results show that the ESOC presents better performance in terms of power generation, guaranteed output and assurance rate. In detail, the annual power generation of ESOC can be increased by 0.9%, the total guaranteed output can be increased by 3.4% and the assurance rate can be increased by 9.6%, which indicates that the proposed ESOC method can greatly improve the hydropower energy efficiency and reliability of cascade reservoirs’ power supply.

Model Reference Adaptive Control for Hybrid Electric Vehicle With Dual Clutch Transmission Configurations

This paper proposes the use of an adaptive control of a hybrid electric vehicle with dual clutch transmission (HDCT). First, this paper shows mathematical equations for the nonlinear system. Then it presents the linearized model for the proposed system. The control objective of the model reference adaptive controller (MRAC) considered in this paper is to minimize fuel consumption and reduce torque interruption in a hybrid electric vehicle. The MRAC can be used to control the electric motor during changes in speed and gear, and the system can adapt to a model that simulates different driver patterns. The effects of using different model responses as input combinations are analyzed in an effort to exploit the over-actuation feature of the system, as is the sensitivity of the performance to various design factors. The simulation results for an HDCT demonstrate that the MRAC achieves reduced torque interruption and less vehicle jerk compared to the conventional method of operation.

Control of a hybrid electric vehicle with dual clutch transmission configurations during mode transition

Mode transitions are significant events in the operation of a hybrid electric vehicle with dual clutch transmission (HDCT). Owing to the friction induced discontinuity of the clutch torque, seamless transition is difficult to achieve. First, this paper presents mathematical equations for the nonlinear system. Then it presents the linearised model for the proposed system. The control objective of the model reference adaptive controller (MRAC) considered in this paper is to minimise fuel consumption and reduce torque interruption in a hybrid electric vehicle (HEV). The simulation and experimental results from an HDCT demonstrate that the MRAC achieves reduced torque interruption and less vehicle jerk compared to the conventional operation method, in addition to smooth and fast transition from pure electrical driving to hybrid driving.

Control of a hybrid electric vehicle with dual clutch transmission configurations during mode transition

Mode transitions are significant events in the operation of a hybrid electric vehicle with dual clutch transmission (HDCT). Owing to the friction induced discontinuity of the clutch torque, seamless transition is difficult to achieve. First, this paper presents mathematical equations for the nonlinear system. Then it presents the linearised model for the proposed system. The control objective of the model reference adaptive controller (MRAC) considered in this paper is to minimise fuel consumption and reduce torque interruption in a hybrid electric vehicle (HEV). The simulation and experimental results from an HDCT demonstrate that the MRAC achieves reduced torque interruption and less vehicle jerk compared to the conventional operation method, in addition to smooth and fast transition from pure electrical driving to hybrid driving.

Studying Operation Rules of Cascade Reservoirs Based on Multi-Dimensional Dynamics Programming

Although many optimization models and methods are applied to the optimization of reservoir operation at present, the optimal operation decision that is made through these models and methods is just a retrospective review. Due to the limitation of hydrological prediction accuracy, it is practical and feasible to obtain the suboptimal or satisfactory solution by the established operation rules in the actual reservoir operation, especially for the mid- and long-term operation. In order to obtain the optimized sample data with global optimality; and make the extracted operation rules more reasonable and reliable, this paper presents the multi-dimensional dynamic programming model of the optimal joint operation of cascade reservoirs and provides the corresponding recursive equation and the specific solving steps. Taking Li Xianjiang cascade reservoirs as a case study, seven uncertain problems in the whole operation period of the cascade reservoirs are summarized after a detailed analysis to the obtained optimal sample data, and two sub-models are put forward to solve these uncertain problems. Finally, by dividing the whole operation period into four characteristic sections, this paper extracts the operation rules of each reservoir for each section respectively. When compared the simulation results of the extracted operation rules with the conventional joint operation method; the result indicates that the power generation of the obtained rules has a certain degree of improvement both in inspection years and typical years (i.e., wet year; normal year and dry year). So, the rationality and effectiveness of the extracted operation rules are verified by the comparative analysis.

No radiological and clinical advantages with patient-specific positioning guides in total knee replacement

Background and purpose — Although the use of patient-specific positioning guides (PSPGs) in total knee replacement (TKR) in theory is promising, the technique has not yet proven its superior- ity compared with the conventional method. We compared radio- logical alignment and clinical outcome between TKR performed with the use of PSPGs and the conventional operation method.Patients and methods — 3 hospitals participated in a prospec- tive trial. 109 patients were randomized to either the conventional method or to the use of PSPGs. Postoperatively a full-length standing anteroposterior radiograph and a postoperative CT scan were taken. On the CT scan the alignments were measured for both the femoral and tibial components in the frontal, sagit- tal, and axial plane. The Knee injury and Osteoarthritis Outcome Score (KOOS), the Eurocol-5D-3L (Eq5D) descriptive system and visual analogue scale (VAS), a pain score (NRS), and range of motion (ROM) were recorded preoperatively, and at 3 months, 1, and 2 years. The operation time and length of hospital stay were recorded.Results — 90 patients were available for postoperative CT mea- surements. A statistically significant difference was found between the conventional TKR instrumentation and the use of PSPGs for the frontal femoral (mean (SD) 0.6° (1.7) vs. –0.3° (2.2), CI 0.08 to 1.69) and tibial (–0.3° (1.5) vs. 0.9° (2.1), CI –1.98 to –0.44) compo- nent angles and for the tibial alignment in the sagittal plane (–3.8° (3.0) vs. –2.2° (2.5), CI –2.72; –0.42). The proportions of outliers were similar between the groups as well as the hip–knee–ankle angle, the KOOS sub scores, the Eq5D, pain (NRS), ROM, opera- tion time, and length of hospital stay.Interpretation — The use of PSPGs requires a preoperative CT scan or MRI and the guides have an additional cost. As this study was not able to prove any extra benefit of the use of PSPGs we recommend the conventional operation method for TKR.

Robust Operation of Microgrids via Two-Stage Coordinated Energy Storage and Direct Load Control

This paper proposes a robust optimization approach for optimal operation of microgrids. The uncertain output variation of renewable energy sources (RESs) is addressed by collaboratively scheduling of energy storage (ES) and direct load control (DLC) through a two-stage complementary framework: an hour-ahead charging/discharging of ES and a quarter-hour-ahead activation of DLC. The objective is to maximize the total profit of the microgrid considering operation and maintenance costs of ES units, wind turbines and photovoltaics, and transaction with main grid and customer loads. Assuming the power output of RES randomly varies within a bounded uncertainty set, the problem is modeled to a two-stage robust optimization model and solved by a column-and-constraint generation algorithm. Compared with conventional operation methods, the ES and DLC are coordinated in different time-scales, and RES uncertainties are fully addressed during operation decision-making, ensuring the solutions to be optimal and robust for any realization of uncertainty. The proposed methodology is verified on the IEEE 33-bus distribution system through a wide range of different tests.