Optimization of Blade Geometry of Savonius Hydrokinetic Turbine Based onGenetic Algorithm

Savonius hydrokinetic turbine is a kind of turbine set which is suitable for low-velocity conditions.Unlike conventional turbines,Savonius turbines employ S-shaped blades and have simple internal structures.Therefore,there is a large space for optimizing the blade geometry.In this study,computational fluid dynamics(CFD)numerical simulation and genetic algorithm(GA)were used for the optimal design.The optimization strategies and methods were determined by comparing the results calculated by CFD with the experimental results.The weighted objective function was constructed with the maximum power coefficient Cp and the high-power coefficient range R under multiple working conditions.GA helps to find the optimal individual of the objective function.Compared the optimal scheme with the initial scheme,the overlap ratioβincreased from 0.2 to 0.202,and the clearance ratioεincreased from 0 to 0.179,the blade circumferential angleγincreased from 0°to 27°,the blade shape extended more towards the spindle.The overall power of Savonius turbines was maintained at a high level over 22%,R also increased from 0.73 to 1.02.In comparison with the initial scheme,the energy loss of the optimal scheme at high blade tip speed is greatly reduced,and this reduction is closely related to the optimization of blade geometry.As R becomes larger,Savonius turbines can adapt to the overall working conditions and meet the needs of its work in low flow rate conditions.The results of this paper can be used as a reference for the hydrodynamic optimization of Savonius turbine runners.

Optimal ship imaging for shore-based ISAR using DCF estimation

The optimal imaging time selection of ship targets for shore-based inverse synthetic aperture radar （ISAR） in high sea conditions is investigated. The optimal imaging time includes opti- mal imaging instants and optimal imaging duration. A novel method for optimal imaging instants selection based on the estimation of the Doppler centroid frequencies （DCFs） of a series of images obtained over continuous short durations is proposed. Combined with the optimal imaging duration selection scheme using the image contrast maximization criteria, this method can provide the ship images with the highest focus. Simulated and real data pro- cessing results verify the effectiveness of the proposed imaging method.

EQUIVALENCE OF THREE DIFFERENT KINDS OF OPTIMAL CONTROL PROBLEMS FOR STOKES EQUATIONS

This article presents an equivalence theorem for three different kinds of optimal control problems, which are optimal target control problems, optimal norm control problems, and optimal time control problems. Controlled systems in this study are internally controlled Stokes equations.

Considerations for Optimal Blood Pressure Target of Hypertension

Hypertension is a major risk factor for cardiovascular morbidity and mortality that has led to a huge public health burden.The optimal target of blood pressure(BP)to prevent cardiovascular complications remains unclear.Based on the results of the Systolic BP Intervention Trial(SPRINT)in 2015,the 2017 American College of Cardiology/American Heart Association guidelines for diagnosis and management of high BP in adults has changed the diagnostic threshold from 140/90 to 130/80 mmHg,and the target BP to 130/80 mmHg for nearly all hypertensive patients diagnosed using the new criteria.However,the findings from the SPRINT trial were to an extent contrasting with the results of previous large randomized controlled trials,namely Action to Control Cardiovascular Risk in Diabetes(ACCORD)and Secondary Prevention of Small Subcortical Strokes(SPS3).Besides,the 2018 European Society of Cardiology/European Society of Hypertension guidelines and the 2018 Chinese guidelines have maintained the conventional threshold and recommended target of 140/90 mmHg for most hypertensive patients.Given the special measurement of BP in the SPRINT trial and using an automated measurement system,the intensive systolic BP target of 120 mmHg provided by the SPRINT trial was not widely adopted.Most recently,the Strategy of BP Intervention in the Elderly Hypertensive Patients(STEP)trial,with a higher systolic BP target of 110 to 130 mmHg in the intensive group,confirmed the benefit and safety of intensive BP control in patients with hypertension,in accordance with the SPRINT trial.Here,the results from randomized controlled trials,meta-analyses,and other observational research studies,have been reviewed to evaluate the optimal target of BP treatment and the threshold of diagnostic criteria for hypertension.

Resource prediction and assessment based on 3D/4D big data modeling and deep integration in key ore districts of North China

The North China district has been subjected to significant research with regard to the ore-forming dynamics,processes,and quantitative forecasting of gold deposits;it accounts for the highest number of gold reserves and annual products in China.Based on the top-level design of geoscience theory and the method adopted by the National Key R&D Project(deep process and metallogenic mechanism of North China Craton(NCC)metallogenic system),this paper systematically collects and constructs the geoscience data(district,camp,and deposit scales)in four key gold districts of North China(Jiaojia-Sanshandao,Southern Zhaoping,Wulong,and Qingchengzi).The settings associated with the geological dynamics of gold deposits were quantitatively and synthetically analyzed,namely:NCC destruction,metallogenic events,genetic models,and exploration models.Three-dimensional(3D)and four-dimensional(4D)geological modeling was performed using the big data on the districts,while the district-scale 3D exploration criteria were integrated to construct a quantitative exploration model.Among them,FLAC3D modelling and the Geo Cube software(version 3.0)were used to implement the numerical simulation of the 3D geological models and the constraints of the fluid saturation parameters of the Jiaojia fault to reconstruct the 4D fault structure models of the Jiaojia fault(with a depth of 5000 m).Using Geo Cube3.0,multiple integration modules(general weights of evidence(Wof E),Boost Wof E,Fuzzy Wof E,Logistic Regression,Information Entropy,and Random Forest)and exploration criteria were integrated,while the C-V fractal classification of A,B and C targets in four districts was carried out.The research results are summarized in the following four areas:(1)Four gold districts in the study area have more than three targets(the depth is 3000 m),and the class A,B and C targets exhibit a good spatial correlation with gold bodies that are controlled by mining engineering at depths greater than 1000 m.(2)The Boost Wof E method was used to identify the target optimization in 3D spaces(at depths of 3000–5000 m)of the Jiaojia-Sanshandao,Southern Zhaoping,and Wulong districts.(3)The general Wof E method is based on the Bayesian theory in 3D space and provides robust integration and target optimization that are suitable for the Jiaojia-Sanshandao and Southern Zhaoping districts in the Jiaodong area;it can also be applied to the Wulong district in the Liaodong area using a quantitative genetic model and an exploration model.Random forest is a multi-objective integration and target optimization method for 3D spaces,and it is suitable for the complex exploration model in the Qingchengzi district of the Liaodong area.The genetic model and exploration criteria associated with the exploration model of the Qingchengzi district were constrained by the common characteristics of the gold fault structure,magmatic rock emplacement in North China,and the strata fold and interlayer detachment structure.(4)Based on the gold reserves and the 3D block unit model of the Sanshandao gold deposit in the Jiaojia-Sanshandao district,the gold contents of the 3D block units in class A and B targets of the ore concentration were estimated to be 65.5%and 25.1%,respectively.The total Au resources of the optimized targets below a depth of 3000 m were 3908 t(including 1700 t reserves),and the total Au resources of the targets at depths from 3000 to 5000 m were 936 t.The study shows that the deep gold deposits in the four gold districts of North China exhibit a strong"transport-deposition"spatial correlation with potential targets.These"transport-deposition"spatial models represent the tectonic-magmatic-hydrothermal activities of the metallogenic system associated with the NCC destruction events and indicate the Au enrichment zones.

Reactive Navigation of Underwater Mobile Robot Using ANFIS Approach in a Manifold Manner

Learning and self-adaptation ability is highly required to be integrated in path planning algorithm for underwater robot during navigation through an unspecified underwater environment. High frequency oscillations during underwater motion are responsible for nonlinearities in dynamic behavior of underwater robot as well as uncertainties in hydrodynamic coefficients. Reactive behaviors of underwater robot are designed considering the position and orientation of both target and nearest obstacle from robot s current position. Human like reasoning power and approximation based learning skill of neural based adaptive fuzzy inference system（ANFIS）has been found to be effective for underwater multivariable motion control. More than one ANFIS models are used here for achieving goal and obstacle avoidance while avoiding local minima situation in both horizontal and vertical plane of three dimensional workspace.An error gradient approach based on input-output training patterns for learning purpose has been promoted to spawn trajectory of underwater robot optimizing path length as well as time taken. The simulation and experimental results endorse sturdiness and viability of the proposed method in comparison with other navigational methodologies to negotiate with hectic conditions during motion of underwater mobile robot.

Ready-to-implement low-carbon retrofit of coal-fired power plants in China:Optimal scenarios selection based on sludge and photovoltaic utilization

Currently the flexible demand for high proportion penetration of renewable energy depends on coal-fired units(CFUs),and the large-scale phase-out of CFUs in a short time is not realistic in China.Due to urban expansion,approximately 458 Chinese coal-fired power plants(CFPPs)are now located in cities.Limited by space,urban CFUs face difficulty in becoming equipped with carbon capture and storage systems.This presents a sizeable challenge for the low-carbon transition of urban CFPPs and carbon neutral processes.Here,we present a ready-to-implement method to reduce the carbon emission of CFPPs in limited space:roof photovoltaic-assisted power generation combined with sludge cocombustion for coal-fired power generation systems(PVSCs).We also consider nonurban CFPPs with the method of roof photovoltaic-assisted power generation(PVs)only.Based on remaining life cycle analysis,we find that the PVSCs could save 28.47 Mt of coal,reduce CO_(2)emissions by 69.76 Mt,treat 125.70 Mt of sludge,and also generate 12.08 billion RMB worth of electricity revenue per year.In addition,our scenario analysis shows that PVSCs are more profitable when choosing an urban CFU with a remaining life of more than 12 years and while the sludge treatment subsidy is set at 100 RMB t
1.Under strict and lenient CFU decommissioning policies,CFUs with a remaining life of between 19 and 30 years and between 13 and 24 years should be selected for PVs,respectively.Thus,we conclude that PVSCs can not only generate economic benefits but also facilitate carbon reduction and solid waste treatment.