Study on the Relationship between Structural Aspects and Aerodynamic Characteristics of Archimedes Spiral Wind Turbines

A combined experimental and numerical research study is conducted to investigate the complex relationship between the structure and the aerodynamic performances of an Archimedes spiral wind turbine(ASWT).Two ASWTs are considered,a prototypical version and an improved version.It is shown that the latter achieves the best aerodynamic performance when the spread angles at the three sets of blades areα_(1)=30°,α_(2)=55°,α3=60°,respectively and the blade thickness is 4 mm.For a velocity V=10 m/s,a tip speed ratio(TSR)=1.58 and 2,the maximum CP values are 0.223 and 0.263 for the prototypical ASWT and improved ASWT,respectively,and the maximum C_(P) enhancement is 17.93%.For V=10 m/s and TSR=2,the CP values of the prototypical ASWT and improved ASWT are 0.225 and 0.263,respectively,with an aerodynamic performance enhancement of 16.88%.Through mutual verification of the test outcomes and numerical results,it is concluded that the proposed approach can effectively lead to aerodynamic performance improvement.

Binary Archimedes Optimization Algorithm for Computing Dominant Metric Dimension Problem

In this paper,we consider the NP-hard problem of finding the minimum dominant resolving set of graphs.A vertex set B of a connected graph G resolves G if every vertex of G is uniquely identified by its vector of distances to the vertices in B.A resolving set is dominating if every vertex of G that does not belong to B is a neighbor to some vertices in B.The dominant metric dimension of G is the cardinality number of the minimum dominant resolving set.The dominant metric dimension is computed by a binary version of the Archimedes optimization algorithm(BAOA).The objects of BAOA are binary encoded and used to represent which one of the vertices of the graph belongs to the dominant resolving set.The feasibility is enforced by repairing objects such that an additional vertex generated from vertices of G is added to B and this repairing process is iterated until B becomes the dominant resolving set.This is the first attempt to determine the dominant metric dimension problem heuristically.The proposed BAOA is compared to binary whale optimization(BWOA)and binary particle optimization(BPSO)algorithms.Computational results confirm the superiority of the BAOA for computing the dominant metric dimension.

Performance analysis of single-focus phase singularity based on elliptical reflective annulus quadrangle-element coded spiral zone plates

Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we propose an efficient methodology to combine the merit of elliptical reflective zone plates(ERZPs) and the advantage of spiral zone plates(SZPs) in establishing a specific single optical element, termed elliptical reflective annulus quadrangle-element coded spiral zone plates(ERAQSZPs) to generate single-focus phase singularity. Differing from the abrupt reflectance of the ERZPs, a series of randomly distributed nanometer apertures are adopted to realize the sinusoidal reflectance. Typically, according to our physical design, the ERAQSZPs are fabricated on a bulk substrate;therefore, the new idea can significantly reduce the difficulty in the fabrication process. Based on the Kirchhoff diffraction theory and convolution theorem, the focusing performance of ERAQSZPs is calculated. The results reveal that apart from the capability of generating optical vortices,ERAQSZPs can also integrate the function of focusing, energy selection, higher-order foci elimination, as well as high spectral resolution together. In addition, the focusing properties can be further improved by appropriately adjusting the parameters, such as zone number and the size of the consisted primitives. These findings are expected to direct a new direction toward improving the performance of optical capture, x-ray fluorescence spectra, and forbidden transition.

Terahertz quasi-perfect vortex beam with integer-order and fractional-order generated by spiral spherical harmonic axicon

We propose a new method to generate terahertz perfect vortex beam with integer-order and fractional-order. A new optical diffractive element composed of the phase combination of a spherical harmonic axicon and a spiral phase plate is designed and called spiral spherical harmonic axicon. A terahertz Gaussian beam passes through the spiral spherical harmonic axicon to generate a terahertz vortex beam. When only the topological charge number carried by spiral spherical harmonic axicon increases, the ring radius of terahertz vortex beam increases slightly, so the beam is shaped into a terahertz quasi-perfect vortex beam. Importantly, the terahertz quasi-perfect vortex beam can carry not only integer-order topological charge number but also fractional-order topological charge number. This is the first time that vortex beam and quasi-perfect vortex beam with fractional-order have been successfully realized in terahertz domain and experiment.

Motorized spiral enteroscopy:A cautious step forward in technological innovation

With the continuous advancement in medical technology,endoscopy has gained significant attention as a crucial diagnostic tool.The introduction of motorized spiral enteroscopy(MSE)represents a significant advancement in the diagnosis and treatment of small bowel diseases.While there are safety concerns and a high reliance on the operator’s skills,MSE should not be disregarded entirely.Instead,it should be considered as a supplementary endoscopic technique,particularly in situations where conventional endoscopy proves ineffective.Through continuous research and technical optimization,MSE has the potential to become an im-portant addition to the endoscopy toolbox in the future.We call on colleagues in the industry to work together to promote the improvement of MSE technology through continuous research and practice,with the aim to bring out its unique value in endoscopy while ensuring patient safety.

Device-assisted enteroscopy: Are we ready to dismiss the spiral?

Motorized spiral enteroscopy(MSE)is the latest advance in device-assisted enteroscopy.Adverse events related to MSE were discussed in a recent large systematic review and meta-analysis and were directly compared with those of balloon enteroscopy in a case-matched study and a randomized controlled trial.Following the real-life application of MSE,an unexpected safety issue emerged regarding esophageal injury and the technique has been withdrawn from the global market,despite encouraging results in terms of diagnostic and therapeutic yield.We conducted an Italian multicenter real-life prospective study,which was prematurely terminated after the withdrawal of MSE from the market.The primary goals were the evaluation of MSE performance(both diagnostic and therapeutic)and its safety in routine endoscopic practice,particularly in the early phase of introduction in the endoscopic unit.A subanalysis,which involved patients who underwent MSE after unsuccessful balloon enteroscopy,demonstrated,for the first time,the promising performance of MSE as a rescue procedure.Given its remarkable performance in clinical practice and its potential role as a backup technique following a previously failed enteroscopy,it may be more appropriate to refine and enhance MSE in the future rather than completely abandoning it.

Fusion of Spiral Convolution-LSTM for Intrusion Detection Modeling

Aiming at the problems of low accuracy and slow convergence speed of current intrusion detection models,SpiralConvolution is combined with Long Short-Term Memory Network to construct a new intrusion detection model.The dataset is first preprocessed using solo thermal encoding and normalization functions.Then the spiral convolution-Long Short-Term Memory Network model is constructed,which consists of spiral convolution,a two-layer long short-term memory network,and a classifier.It is shown through experiments that the model is characterized by high accuracy,small model computation,and fast convergence speed relative to previous deep learning models.The model uses a new neural network to achieve fast and accurate network traffic intrusion detection.The model in this paper achieves 0.9706 and 0.8432 accuracy rates on the NSL-KDD dataset and the UNSWNB-15 dataset under five classifications and ten classes,respectively.

Effectiveness of magnetic resonance imaging and spiral computed tomography in the staging and treatment prognosis of colorectal cancer

BACKGROUND Colorectal cancer(CRC)is a prevalent cancer type in clinical settings;its early signs can be difficult to detect,which often results in late-stage diagnoses in many patients.The early detection and diagnosis of CRC are crucial for improving treatment success and patient survival rates.Recently,imaging techniques have been hypothesized to be essential in managing CRC,with magnetic resonance imaging(MRI)and spiral computed tomography(SCT)playing a significant role in enhancing diagnostic and treatment approaches.AIM To explore the effectiveness of MRI and SCT in the preoperative staging of CRC and the prognosis of laparoscopic treatment.METHODS Ninety-five individuals admitted to Zhongshan Hospital Xiamen University underwent MRI and SCT and were diagnosed with CRC.The precision of MRI and SCT for the presurgical classification of CRC was assessed,and pathological staging was used as a reference.Receiver operating characteristic curves were used to evaluate the diagnostic efficacy of blood volume,blood flow,time to peak,permeability surface,blood reflux constant,volume transfer constant,and extracellular extravascular space volume fraction on the prognosis of patients with CRC.RESULTS Pathological biopsies confirmed the following CRC stages:23,23,32,and 17 at T1,T2,T3,and T4,respectively.There were 39 cases at the N0 stage,22 at N1,34 at N2,44 at M0 stage,and 51 at M1.Using pathological findings as the benchmark,the combined use of MRI and SCT for preoperative TNM staging in patients with CRC demonstrated superior sensitivity,specificity,and accuracy compared with either modality alone,with a statistically significant difference in accuracy(P<0.05).Receiver operating characteristic curve analysis revealed the predictive values for laparoscopic treatment prognosis,as indicated by the areas under the curve for blood volume,blood flow,time to peak,and permeability surface,blood reflux constant,volume transfer constant,and extracellular extravascular space volume fraction were 0.750,0.683,0.772,0.761,0.709,0.719,and 0.910,respectively.The corresponding sensitivity and specificity values were also obtained(P<0.05).CONCLUSION MRI with SCT is effective in the clinical diagnosis of patients with CRC and is worthy of clinical promotion.

Dark Matter Density Profiles of Selected Spiral Galaxies

Understanding the dark matter distribution throughout a galaxy can provide insight into its elusive nature. Numerous density profiles, such as the Navarro, Frenk and White model, have been created in an attempt to study this distribution through analyzing orbital velocities of luminous matter and modeling dark matter distributions to explain these observations. However, we are interested in a simple model to consider the significant fluctuations in rotation curves at larger radii. Therefore, our model is much simpler compared to those previously mentioned. Our model used all the observational data available for four selected galactic rotation curves. These data present a significant variation in the orbital velocity of matter at the same distances. By running real observational data through our model, we show that the density of the dark matter within them shows real complex structure, which is not suggested by other computational models. Our aim of this paper is to model this structure and then speculate as to the cause and implications of these density fluctuations.

The Origin of the Flat Rotation Curves in Spiral Galaxies: The Hidden Roles of Glitching SMDEOs and Emission of Gravitational Waves

Supermassive DEOs (SMDEOs) are cosmologically evolved objects made of irreducible incompressible supranuclear dense superfluids: The state we consider to govern the matter inside the cores of massive neutron stars. These cores are practically trapped in false vacua, rendering their detection by outside observers impossible. Based on massive parallel computations and theoretical investigations, we show that SMDEOs at the centres of spiral galaxies that are surrounded by massive rotating torii of normal matter may serve as powerful sources for gravitational waves carrying away roughly 1042 erg/s. Due to the extensive cooling by GWs, the SMDEO-Torus systems undergo glitching, through which both rotational and gravitational energies are abruptly ejected into the ambient media, during which the topologies of the embedding spacetimes change from curved into flatter ones, thereby triggering a burst gravitational energy of order 1059 erg. Also, the effects of glitches found to alter the force balance of objects in the Lagrangian-L1 region between the central SMDEO-Torus system and the bulge, enforcing the enclosed objects to develop violent motions, that may explain the origin of the rotational curve irregularities observed in the innermost part of spiral galaxies. Our study shows that the generated GWs at the centres of galaxies, which traverse billions of objects during their outward propagations throughout the entire galaxy, lose energy due to repeatedly squeezing and stretching the objects. Here, we find that these interactions may serve as damping processes that give rise to the formation of collective forces f∝m(r)/r, that point outward, endowing the objects with the observed flat rotation curves. Our approach predicts a correlation between the baryonic mass and the rotation velocities in galaxies, which is in line with the Tully-Fisher relation. The here-presented self-consistent approach explains nicely the observed rotation curves without invoking dark matter or modifying Newtonian gravitation in the low-field approximation.

Time-Varying Mesh Stiffness Calculation and Dynamic Modeling of Spiral Bevel Gear with Spalling Defects

Time-varying mesh stiffness(TVMS)is a vital internal excitation source for the spiral bevel gear(SBG)transmission system.Spalling defect often causes decrease in gear mesh stiffness and changes the dynamic characteristics of the gear system,which further increases noise and vibration.This paper aims to calculate the TVMS and establish dynamic model of SBG with spalling defect.In this study,a novel analytical model based on slice method is proposed to calculate the TVMS of SBG considering spalling defect.Subsequently,the influence of spalling defect on the TVMS is studied through a numerical simulation,and the proposed analytical model is verified by a finite element model.Besides,an 8-degrees-of-freedom dynamic model is established for SBG transmission system.Incorporating the spalling defect into TVMS,the dynamic responses of spalled SBG are analyzed.The numerical results indicate that spalling defect would cause periodic impact in time domain.Finally,an experiment is designed to verify the proposed dynamic model.The experimental results show that the spalling defect makes the response characterized by periodic impact with the rotating frequency of spalled pinion.

水平多层spiral型地埋管数值模拟研究及换热特性分析

本文基于COMSOL软件建立了水平spiral型多层地埋管群传热三维数值模拟模型,并对其换热性能和温度场进行分析研究。结果表明:对比水平spiral多层并联管群来说,远离注入端的地埋管管内温度相对较低。地埋管群周围地层温度有所升高,远离注入端的地层温度变化相对较小。地埋管群的换热量随循环流体的流速增加而增加,但增幅降低。在进行换热器设计时,应合理控制循环水的流速。3层螺旋地埋管群的换热量略高,但层间干扰明显,建议选用2层并联螺旋管群。

试论Archimedes的数学思想

依据 Archimedes的数学贡献 ,尤其是 Archimedes在求抛物线弓形面积时所创立的方法 ,分析了Archim edes的数学思想 ,认为 Archimedes既善于进行巧妙的物理论证 ,又善于进行严格的数学论证。由Archim edes的数学思想得到的启示是 :巧妙的物理论证是科学发现的重要方法 ;严格的数学论证是确立结论的必需步骤 ;要精选若干基本原理 ,作为论证的基础 ;要献身科学真理 ,不为俗世需求所动摇。

结构参数对二维Archimedes A7晶格光子晶体禁带的影响

利用平面波展开法对空气背景中介质圆柱和方柱构造的二维Archimedes A7晶格光子晶体的禁带结构随介质折射率、填充比的变化关系进行了研究,并进一步计算了介质方柱的旋转角度对完全光子禁带宽度的影响.研究发现,介质圆柱构造的Archimedes A7晶格结构在介质柱折射率最低为n=2.40时出现完全光子禁带,当n=2.60时禁带宽度达到最大值.介质方柱构造的Archimedes A7晶格结构在介质柱折射率n=3.80时完全禁带宽度达到最大值,且随着折射率的增加禁带宽度变化很小;在介质方柱折射率恒定情况下,其最大禁带宽度与旋转角度无关,但旋转后出现完全禁带的填充比范围明显扩大.

一类特殊的非Archimedes序域其构造

本文讨论了一类特殊的非Archimedes序列，这种序域可用来以简单而自然的方法定义实数，这种序域的构造方式也是自然的，自由然数集N的一种特殊保真扩张模型N出发，使用通常的分数程序来构造，本文在讨论N的保真扩张的一般方法基础上着重讨论相论容方程组方法与超滤方法。

Archimedes螺线盘转动问题的差分处理

所计算的匀质可燃Archimedes螺线盘 ,是一个在水平支撑面上发生燃喷并做定轴转动的变质量力学系统 .采用差分方法对其进行了有关计算 。

二维介质柱型Archimedes(4，8^2)复式晶格光子晶体禁带特性研究

采用平面波展开法分别模拟了空气背景下由介质圆柱和方柱构造的二维Archimedes(4,82)复式晶格光子晶体的能带结构,讨论了介质柱形状、折射率、填充比和旋转对称性等因素对完全光子禁带的影响.研究发现,当折射率在2.60到5.40之间时,介质圆柱和方柱构造的二维Archimedes(4,82)复式晶格光子晶体都出现了完全光子禁带.随着折射率的增大,最大完全禁带宽度并非随之增大而是存在峰值,介质圆柱型晶格在折射率为2.80时出现峰值;介质方柱型晶格在折射率为2.80和4.40两处出现峰值,且旋转介质方柱能够明显增大禁带宽度,同时存在最佳旋转角度.分析结果表明,在最大完全禁带处,折射率、填充比以及旋转角度等因素的变化对禁带特性的影响很小.

Two-dimensional distributed strain sensing with an Archimedean spiral arrangement in optical frequency domain reflectometry

We demonstrate a distributed two-dimensional(2D)strain-sensing system in optical frequency domain reflectometry(OFDR)with an Archimedean spiral arrangement of the sensing fiber.The Archimedean spiral describes a simple relationship between the radial radius and polar angle,such that each circle(the polar angle from0 to 2π)can sense the 2D strain in all directions.The strain between two adjacent circles can also be easily obtained because an Archimedean spiral facilitates sensing of every angle covering the full 2D range.Based on the mathematical relation of Archimedean spirals,we deduce the relationship between the one-dimensional position of the sensing fiber and 2D distribution in polar coordinates.The results of the experiment show that an Archimedean spiral arrangement system can achieve 2D strain sensing with different strain load angles.

Improved Archimedes Optimization Algorithm with Deep Learning Empowered Fall Detection System

Human fall detection(FD)acts as an important part in creating sensor based alarm system,enabling physical therapists to minimize the effect of fall events and save human lives.Generally,elderly people suffer from several diseases,and fall action is a common situation which can occur at any time.In this view,this paper presents an Improved Archimedes Optimization Algorithm with Deep Learning Empowered Fall Detection(IAOA-DLFD)model to identify the fall/non-fall events.The proposed IAOA-DLFD technique comprises different levels of pre-processing to improve the input image quality.Besides,the IAOA with Capsule Network based feature extractor is derived to produce an optimal set of feature vectors.In addition,the IAOA uses to significantly boost the overall FD performance by optimal choice of CapsNet hyperparameters.Lastly,radial basis function(RBF)network is applied for determining the proper class labels of the test images.To showcase the enhanced performance of the IAOA-DLFD technique,a wide range of experiments are executed and the outcomes stated the enhanced detection outcome of the IAOA-DLFD approach over the recent methods with the accuracy of 0.997.

Archimedes’ Principle Revisited

Based on Newton’s third law of motion, we present a different but quite general analysis of Archimedes’ principle. This analysis explains the reduction in apparent weight of a submerged object in all cases, regardless of its position in the fluid. We also study the case in which the object rests on the bottom of the container where the net hydrostatic force on it is downward, and explain where in this case the reduction in the apparent weight comes from.