bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two-dimensional numerical simulation of the performance of orthopter-type wind turbine with S-shaped arc blades
Authors: Shima Takuma , Kiwata Takahiro , Kono Takaaki 
Published: May 2022

Abstract
This paper evaluates the performance of an orthopter-type wind turbine with S-shaped arc blades using two-dimensional numerical simulations. For this variable-pitch vertical-axis wind turbine, each blade rotates on its own axis while all blades rotate on the main axis. This configuration ensures that the blades rotate around their own axes by 360° for every two-full revolutions of the main rotor. The central angle φ of an S-shaped arc blade was set to 60°, 90°, 120°, or 150°. The power coefficient Cp
for a normal S-shaped arc blade is larger than that for an inverse S-shaped arc blade. The maximum power coefficient Cpmax
for the normal S-shaped arc blade with φ = 90°-120° is suitable for an orthopter-type wind turbine. The inlet angle of the wind turbine θP
was set 0°, ±5°, ±15°, or ±30°. The maximum power coefficient Cpmax
was large for θP
values of –15° to +5°. This wind turbine can achieve passive yaw control by means of a tail vane installed on the sprocket of main axis.
Preliminary flow measurements of a small-scale, vertical axis wind turbine for the analysis of blockage influence in wind tunnels
Authors: Santamaría Luis , Díaz Katia María Argüelles , Pereiras Bruno , Vega Mónica Galdo , Pérez José González , Velarde-Suáréz Sandra , Oro Jesús Manuel Fernández 
Published: May 2022

Abstract
The development of competitive lift vertical axis wind turbines (VAWTs) is yet a challenge in wind power research. New designs typically require wind tunnel testing before in site implementation. One of the major problems at the laboratory stage is the appearance of a significant flow blockage for small scale models, which affects the performance of the tested wind turbines and prevents the direct extrapolation of results to open field conditions without previous correction. Unfortunately, a suitable blockage correction for lift VAWTs has not been achieved yet, so more studies are needed in this research field to fill the gap. As part of preliminary work with this aim, a small scale VAWT prototype has been designed, constructed, and tested in a 1.15×1 m2 test section wind tunnel with a semi-closed chamber, featuring a blockage ratio of 0.37. Preliminary aerodynamic measurements were performed for different tip speed ratios on the downstream near wake using a special 3-hole pressure probe. Results show that the wake velocity profiles present a velocity increase around the prototype with a low velocity region in the windward quadrant of the turbine, indicating an important influence of the tunnel boundaries. These preliminary measurements have given an initial insight on the aerodynamic relationships between turbine performance and flow patterns. Additionally, they will help to devise an appropriate strategy for the following experiments, with the final objective of developing a blockage correction for small scaled VAWTs.
Casing treatment using oblique slots for a single-stage transonic axial compressor
Authors: Vuong Tien-Dung , Kim Kwang-Yong 
Published: May 2022

Abstract
This work presents a casing treatment design using oblique slots to improve the stability of a single-stage transonic axial compressor, NASA Stage 37. 36 individual slots are distributed uniformly on the rotors’ shroud. Numerical simulations were performed to find the effects of the casing treatment on the compressor’s stability as well as the adiabatic efficiency and pressure ratio. The oblique slots were found to effectively alleviate the negative influence of the tip leakage flow on the compressor’s performance, thus increasing the stall margin without significant sacrifices in efficiency and pressure rise. Three geometric parameters of the casing treatment were examined. The results showed that, with the oblique slots, the highest stall margin reached 13.59% - a 37% increase from the smooth casing case, with about 0.17% and 0.09% reductions in the peak efficiency and maximum pressure ratio, respectively.
Effect of side-wall ribs on heat transfer and flow characteristics in internal cooling passage of gas turbine blade
Authors: Matsuura Kensuke , Yoshida Tetsuya , Hata Daisuke , Miyabe Masahiro 
Published: May 2022

Abstract
The effect of the side-wall ribs on the heat transfer and flow characteristics in the blade internal cooling passage was conducted by both experiments and CFD calculations, and its optimal shape, arrangement and further development were investigated. It is necessary for the side-wall ribs to optimize the shape for the purpose of not increasing the total pressure loss as much as possible. In this study, Λ and V shaped side-wall ribs with aspect ratio of 1.0 were numerically and experimentally investigated. In addition, with the aim of reducing the total pressure loss, the side-wall ribs with slit which were modified by removing the central part of the Λ and V shaped ribs and those combinations were investigated. As a result, it was confirmed that the combination of V and V shaped with slit were promising and multi-objective optimization using a genetic algorithm was conducted for it. The design parameters were the angle of attack (AoA) for both V shaped with slit and V shaped side-wall ribs, the slit width of V shaped and the height of ribs. The objective functions were Nusselt number, total pressure loss coefficient and thermal performance. The optimized shape has the highest thermal performance, although there exists a strong trade-off relationship between heat transfer coefficient and total pressure loss coefficient. Moreover, the effect of aspect ratio was investigated with considering the vortices distributions in the three-dimensional space. In this study, two kinds of aspect ratio, W/H=0.5 and 2.0 were numerically investigated. As a result, it was found that W/H=0.5 is the best with respect to thermal performance due to pressure loss reduction because the interaction of vortices were suppressed. In conclusion, the side-wall ribs promote the reattachment of separated cooling air flow and the high heat transfer coefficient region can be expanded and the thermal performance can be improved.
Trajectory analysis of air-entrainment vortex in a suction sump
Authors: Noguchi T , Komatsu K , Hirata K 
Published: May 2022

Abstract
We attempt to develop the algorithm that identify the trajectory of the air strings from the image data. As a result, we reveal the behaviour of the vortex. Furthermore, we extract the air string with the longest life, and reveal its trajectory with poor regularity. In some cases, the air string tends to turn back and to attract to the pipe. But in some cases, the air string tends to move linearly and to have the trajectory that moves away from the pipe. In addition, the air string sometimes takes the trajectory that wraps around the wake along the pipe.
Nature inspired design modification of fluidic diode for wave energy harvesting device
Authors: Hithasih Doddamani , Samad Abdus , Takao Manabu 
Published: May 2022

Abstract
A fluidic diode (FD) coupled with the unidirectional turbine (UT) can improve its flow rectification operating in a bi-directional airflow. However, the shape of the FD is not standardized like other fluidic components, and they are usually problem-specific. The performance of the FD is given by diodicity, which is the ratio of pressure drop for the reverse to forward direction. This article aims to improve the performance of the FD proposed for wave energy application by modifying its shape, which is inspired by the bud of the lotus flower. The modified model is numerically studied by solving three-dimensional steady-state Reynolds Averaged Navier Stokes equations using the commercial computational fluid dynamics software ANSYS FLUENT 16.2. The proposed modification had a lesser pressure drop in both directions compared to the base model. The detailed flow physics and performance analysis of the modified FD are presented.
Effect of blade skew, endplate and casing groove on the aerodynamic performance of Wells turbine for OWC: a review
Authors: Kumar Amit , Das Tapas K. , Samad Abdus 
Published: May 2022

Abstract
The geometry modification of a bidirectional flow Wells turbine used in a wave energy converter can assist in overcoming the mammoth stall triggered by tip leakage, secondary flow on the blade surface, corner vortex, passage vortex, tip scrubbing, tip trailing edge vortex, boundary layer formation on hub and casing, and combination of all the listed making it a complex 3D flow. As the flow varies almost sinusoidally in each wave cycle in the ocean, it is inevitable to get a turbine having a higher operating range and average power output. Skewing a blade reduces the radial flow on the blade suction surface. A casing groove and endplate reduce tip leakage flow. These modifications give a significant improvement in the turbine performance. There are several design alternatives reported in the articles, and they have shown different results. In this article, the modifications and their effects are discussed in detail and concluded for future recommendations.
Research on Target Imaging Scene Simulation for Photoelectronic Tracking
Authors: Jiang Kai , Mao Zheng 
Published: May 2022

Abstract
In this paper, the 3D visual display and generation of target in optoelectronic tracking are researched by simulation. 3ds max software is used to model the target, the target model is converted into code files by Deep Exploration and added into the system model. The key point is to associate the target model track and size ratio with the actual target to approach the real battlefield environment. The image data provided by the scene building is tracked by the internal image processing algorithm of photoelectric tracking such as the Canny-based edge tracking. The experiment will compare the tracking of the same target in same algorithm but different backgrounds, and the same backgrounds but different algorithm. Result can see that through the experimental data, the application of the simulated sky background, and the proportion relationship between real target and target in simulation scene, provides a high authenticity data support for the image processing algorithm of self-propelled gun photoelectric tracking system.
The ECAP Process Simulation and Experiments with Different Back Pressures for Magnesium Alloy
Authors: Quang P 
Published: May 2022

Abstract
According to this study, the ECAP process with different BP is performed on the engineering magnesium alloy (AZ31). The effect of BP on the strain condition and flow paths may differ as the statically deformed portion of the sample passes through the strain zone. The BP application of 25, 50 and 100 MPa brings about the forward typical shear rotation of structural components in the horizontal direction. The complex (20 x 20 x 200) mm3
ECAP engine is applied with movable outer walls and specially designed sliding bottoms for low friction (moving die). The flow model is made by a cubic flow net of the DEFORM software tool on the workpiece. Structural features and initial micro-hardness measurements made on the x and y planes of the workpiece also received a special attention. Since BP leads to increased density the micro-hardness could be improved and ascribed to the change in texture.
Three-Dimensional Modeling and Simulation of Normal Knee Joint Motion
Authors: Alemayehu Dereje Gobena , Zhang Zhi , Tahir Elena , Gateau Djovensky , Ma Xing 
Published: May 2022

Abstract
Three-dimensional (3D) modeling and simulation have important applications in orthopedic surgery. This technology can be used to create a 3D model of anatomic structures that can be used as a template to perform surgical simulations preoperatively. This study was aimed to apply 3D modeling to simulate flexion of a human knee based on the normal knee joint motion that includes tibial internal rotation and femoral rollback under high degree knee flexion. A 3D knee joint model was constructed from a two-dimensional computed tomography image of a normal knee joint. Based on the reconstructed 3D model of the knee joint, simulation of knee joint flexion at 90,100,110,120,130, and 140 degrees was conducted while replicating the normal knee joint motion. The rotation, translation, and tilt wizards allow the simulation of a complex motion that happens at the human knee joint. Simulation of knee joint motion allows replication of the complex motion during a gait cycle and can offer an alternative option to in vivo experiments to simulate surgical techniques, analyse knee implants and conduct biomechanical studies. This study has demonstrated that 3D modeling and simulation technology is an important tool to study the relationship between the degree of knee flexion and femoral tunnel orientation in anterior cruciate ligament (ACL) reconstruction. Accordingly, the joint flexion angle, and the sagittal and axial drill angles should be taken into consideration in ACL reconstruction.
Bifurcation Analysis and Travelling Wave Solution for a Generalized Time Fractional KdV Equation
Authors: Wang Yan , Yang Wei , Yang Liu , Wang Nan , Yan Yongsheng , Wang Meng , Li Lingfei 
Published: May 2022

Abstract
By using bifurcation theory of planar dynamic system to a generalized time fractional KdV equation, a large number of solutions including irrational function solution, Jacobian elliptic function solution, trigonometric function solution, solitary solution as well as compacton solution are derived. Under different parametric selection, various kinds of sufficient conditions and numerical simulations are demonstrated to visualize their mechanism.
Effective Ship Domains Considering Ship Encounter Situations and Speeds
Authors: Yang Shujie , Sun Wei 
Published: May 2022

Abstract
Ship domain is an important concept in assessing navigation situation and planning collision avoidance manoeuvres of a ship. For purpose of improving the precision and adaptability of the ship domains, effective ship domains are proposed for ships with different speeds in a variety of encounter situations in this work. Firstly, the COLREGs-based division of encounter types and corresponding collision avoidance actions are further optimized. Therefore, the problem of unclear division of responsibilities caused by the intersection of relative position and relative heading is resolved. On this basis, ship domains are determined by the encounter situations and the target ship’s speed. More specifically, the ship domain is approximated to a circle, and the dependence of the domain size on the encounter situation and the target ship’s speed has been analysed and described, that enable us to determine effective ships domains for ships varying in speeds and encounter situations. The simulation results show that ships can make effective collision-avoidance actions in different encounter scenarios based on the optimized COLREGs-based division of encounter types and effective ship domains.
Design Methods for the Lethality of Fragmentation Warhead based on a Multi-Objective Optimization Algorithm
Authors: Li Xiangyu , Li Fugang , Liang Minzu , Zhang Kefan 
Published: May 2022

Abstract
Fragmentation warhead is the main weapon used to damage personnel and light armored objectives, with the lethal parameters primarily consisting of the number and velocity of fragments. Increasing the lethality of fragmentation warhead is currently the most important development direction for fragmentation warhead. The formation process of natural fragment is complicated and there are several factors that affect the properties of fragment, so there are still many techniques of developing the lethality of fragmentation warhead. In this paper, our object is to focus on the optimization design for the lethality of fragmentation warhead, based on the optimal Latin hypercube test design method and the radial basis function neural network surrogate modelling, taking the number of effective fragments per unit mass and the average kinetic energy of the effective fragments as the optimization objectives, and the explosive charge, the fragment material, the overall structure and initiation method are considered, respectively. The Pareto optimal solution sets under different design variables are obtained, and the optimal matching of multiple design parameters is realized, establishing the integration design method for “explosive - material-structure” of the fragmentation warhead. The research results can provide technical support for the structural optimization design of the fragmentation warhead.
Improved Migratory Bird Migration Algorithm for Flexible Job Shop Scheduling
Authors: Shen Liezheng , Zhen Guohui , Zhu Haiping 
Published: May 2022

Abstract
For flexible job shop scheduling, an improved migratory bird migration algorithm is proposed to minimize the maximum completion time. Firstly, global, local and random selection methods were used to initialize the population, which improved the quality of the initial solution; The structure of migratory bird group was changed by increasing leading birds, and the crossover and mutation operators were introduced to enhance the global optimization ability. And different variable neighborhood search algorithms on critical path were introduced among different bird groups, which improved the local optimization ability of and the diversity of migratory bird groups; The jumping and competition mechanisms were proposed to improve the ability of the algorithm to jump out of the local optimal solution and convergence. Finally, the simulation results of the benchmarks verified the algorithm’s searching ability and stability of the algorithm.
An Floyd-Warshall Evolution Relations Algorithm Based on Social Networks Key Groups
Authors: Gao Zhan , He Junjiang , Li Tao , Chen Yang , Fang Wenbo , Li Zhiyong 
Published: May 2022

Abstract
With the development of the society, people increasingly frequent application in social network, the formation of social networking groups become important step in people’s life. How to analyze the evolution of social network group relations become very important. In this paper, an Floyd-Warshall evolution relations algorithm based on social networks key groups is proposed. Mainly includes four parts, initial construction of social network group relations, social big data acquisition, network group relations weighting, and group relations reconstruction. Experimental results show that, by analyzing group communication frequency, group membership relationship and the number of social group members, the evolution map of social network group relationship can be obtained, which can make a more intuitive analysis and expression of the development process of social network group and the evolution of social network group relationship.
Nonlinear Spectral Unmixing of Hyperspectral Imagery Based on Hapke Model and Relevance Vector Regression Algorithm
Authors: Sun Cheng , Xing Feng , Liu Donghao , Han Jieguo , Yang Bei 
Published: May 2022

Abstract
This paper put forward a nonlinear hyperspectral imagery unmixing method based on Hapke nonlinear spectral mixture model and the relevance vector regression. This paper presents a method of relevance vector regression algorithm for unmixing of hyperspectral images. The spectrum was mixed to train the relevance vector regression algorithm according to Hapke non-linear mixing model. This method made our training process coincident with the physical feature of non-linear spectral mixing process. The experiments of smiulated data and hyperspectral imagery are conducted to validate the methods. The smiulated data and hyperspectral image was used for accuracy assessment. Results show that relevance vector regression algorithm can provide better result as compared with linear spectral unmixing model and support vector regression method. And our method provides better result with relative less relevant vector. The proposed algorithm reduced computational complexity of the spectral unmixing problem.
Modeling of Feature Selection Based on Random Forest Algorithm and Pearson Correlation Coefficient
Authors: Mei Kai , Tan Meifang , Yang Zhihui , Shi Shaoyue 
Published: May 2022

Abstract
This paper establishes a feature selection model to selects 20 molecular descriptors of compounds with the most significant influence on biological activity. Random forest algorithm was used to calculate the correlation between molecular descriptors and pIC50 values of biological activity. In this way, the top 26 molecular descriptors with high correlation were screened out. The Pearson correlation coefficient was used to analyze the 26 molecular descriptors just selected and eliminate the variables with high correlation between the independent variables. By consulting literature, the parameters such as MlogP, XlogP and TopoPSA in the selected molecular descriptors were found that had a prominent effect on the biological activity, indicating that the screening methods and results of the 20 molecular descriptors were reasonable.
Improved ALS Recommendation Algorithm Based on Interest-Value Model
Authors: Wang Zhaoyang , Huang Jianjun , Sun Hongyuan 
Published: May 2022

Abstract
In the era of big data, all kinds of information around, how to effectively get the information others want and achieve recommendation is the original purpose of recommendation algorithm, traditional recommendation has collaborative filtering, content-based, model-based recommendation algorithm. Matrix factorization recommendation algorithm solves the problems of data sparsity and low space utilization brought by dimensional explosion. ALS(Alternating Least Squares) algorithm is one of the matrix factorization and the only one recommendation algorithm implemented in Spark, which is in line with the computation method of big data distributed computing. However, in the traditional ALS, there are still some shortcomings: the determination of the number of Implicit features does not give a clear definition, the information factor is lost after matrix factorization, which leads to the poor interpretability of the decomposed matrix, and the performance parameters of the ALS model are not optimal in terms of performance. Based on the above shortcomings, the IVM-ALS(ALS Based on Interest-Value Model) based on interest-value is proposed, an interest-value model is introduced, a solution to solve the Implicit feature number is introduced, and the feasibility of the feature matrix of the subdivided item is enhanced, so as to meet the actual requirements., And improve the algorithm performance than traditional ALS.
Metamorphic Relations Recognition Method Based on Node Features and Path Features
Authors: Zhang Tongtong , Liu Jie , Yang Xiaohua , Yan Shiyu , Li Meng 
Published: May 2022

Abstract
The classification model of the metamorphic relations of the scientific computing program has four categories, of which the code model occupies an important position. We redefine a metamorphic relations, which is single-line metamorphic relations and it exists in the nuclear power program. And it is more comprehensive compared to other metamorphic relations to reflect the internal logic of the program, while node features and path features can maximize the logical structure of the programs. Based on the above situation, we started from the code layer to study the metamorphic relations, put the control flow chart as the bridge of the code and metamorphic relations, extract node features and path features control flowchart and transform the identification problem of metamorphic relations into the problem of predictive model classification. Apply the identified single-line metamorphic relations to the nuclear power field and detect the effectiveness of the software program. The results show that the method is used to enrich the study of the metamorphic relations with the code level, and further improve the degree of automation of metamorphic tests.