Deterministic methods for prediction of tropical cyclone tracks

ABSTRACT. The paper presents a state-of-art review of different objective techniques available for tropical cyclone track prediction. A brief description of current theories of tropical cyclone motion is given. Deterministic models with statistical and dynamical methods have been discussed. Recent advances in the understanding of cyclone structure and motion aspects have led to improved prediction of tropical cyclones. There has been considerable progress in the field of prediction by dynamical methods. High resolution Limited Area Models (LAM) as well as Global Circulation Models (GCM) are now being used extensively by most of the leading operational numerical weather prediction (NWP) centres in the world The major achievements towards improvement of such models have come from improved horizontal resolution of the models, inclusion of physical processes, use of synthetic and other non-conventional data in the data assimilation schemes and nudging method for initial matching of analysed cyclone centres with corresponding observations. A brief description of further improvement in deterministic approach for prediction of tropical cyclone tracks is outlined.

Design and Control of an Adaptive Knee Joint Exoskeleton Mechanism with Buffering Function

A knee exoskeleton with an adaptive instantaneous rotation center and impact absorption is used for rehabilitation. Due to the human knee joint’s special physiological structure and motion characteristics, the exoskeleton mechanism needs to be designed for both static and dynamic aspects. Therefore, a novel knee exoskeleton mechanism was designed. To adapt to the rotation center of the knee joint, a mechanism with cross-configuration was designed according to the equivalent degree of freedom and the stiffness of the springs was calculated by its combination with gait motion, so that the average force of the human body was minimized. A dynamic model of the exoskeleton was established. To overcome the uncertainty in the parameters of the human and robotic limbs, an adaptive controller was designed and a Lyapunov stability analysis was conducted to verify the system. A simulation was conducted and experimental results show that the tracking error of the knee joint angle between the actual and desired trajectory was within the range of −1 to 1 degree and indicate the effectiveness of the controller.

Simulation Analysis of One Degree of Freedom Motion of Electromagnetic Spherical Joint based on Maxwell

In order to improve the stiffness of the spherical joint of the robot, reduce the difficulty of manufacturing and the complexity of the control system, this paper proposed a method of spherical joint and digital drive of the robot based on the electromagnetic principle. Firstly, introduces the structure and motion principle of the spherical joint of the robot, establishes the mathematical model of the spherical joint and establishes the dynamic model according to the second Lagrange equation. after that, the relationship between the number of ampire-turns of the electromagnet on the spherical joint, the attitude Angle of the rotor and the force of the rotor was obtained by simulating the single degree of freedom of the joint based on Ansys maxwell and Matlab, which provided a basis for the realization of the digital drive of the spherical joint.

3D Flexible Refinement: Structure and Motion of Flexible Proteins from Cryo-EM

Single particle cryo-EM excels in determining static structures of biological macromolecules such as proteins. However, many proteins are dynamic, with their motion inherently linked to their function. Recovering the continuous motion and detailed 3D structure of flexible proteins from cryo-EM data has remained an open challenge. We introduce 3D Flexible Refinement (3DFlex), a motion-based deep neural network model of continuous heterogeneity. 3DFlex directly exploits the knowledge that conformational variability of a protein is often the result of physical processes that transport density over space and tend to conserve mass and preserve local geometry. From 2D image data, the 3DFlex model jointly learns a single canonical 3D map, latent coordinate vectors that specify positions on the protein's conformational landscape, and a flow generator that, given a latent position as input, outputs a 3D deformation field. This deformation field convects the canonical map into appropriate conformations to explain experimental images. Applied to experimental data, 3DFlex learns non-rigid motion spanning several orders of magnitude while preserving high-resolution details of secondary structure elements. Further, 3DFlex resolves canonical maps that are improved relative to conventional refinement methods because particle images contribute to the maps coherently regardless of the conformation of the protein in the image. Together, the ability to obtain insight into motion in macromolecules, as well as the ability to resolve features that are usually lost in cryo-EM of flexible specimens, will provide new insight and allow new avenues of investigation into biomolecular structure and function.

Robotic Arm Using Servo Motor and Arduino Uno Controlled with Potentiometer

Robotic arm has been widely used in many applications, especially in industry. With this kind of advancement, the needs to introduce this technology to students at early age has increased. However, many students still consider this kind of technology as something out of reach. This project aims to create a very simple robotic arm using servo motor and materials which can be easily obtained around the household. The resulting robot is also programmable and electronically movable, thus enabling more freedom of how to move it. This in turn create a good introductory tool for the students to learn about the structure and motion of robotic arm.

Dynamic Interconversion of Metal Active Site Ensembles in Zeolite Catalysis

Catalysis science is founded on understanding the structure, number, and reactivity of active sites. Kinetic models that consider active sites to be static and noninteracting entities are routinely successful in describing the behavior of heterogeneous catalysts. Yet, active site ensembles often restructure in response to their external environment and even during steady-state catalytic turnover, sometimes requiring non-mean-field kinetic treatments to describe distance-dependent interactions among sites. Such behavior is being recognized more frequently in modern catalysis research, with the advent of experimental methods to quantify turnover rates with increasing precision, an expanding arsenal of operando characterization tools, and computational descriptions of atomic structure and motion at chemical potentials and timescales increasingly relevant to reaction conditions. This review focuses on dynamic changes to metal active site ensembles on zeolite supports, which are silica-based crystalline materials substituted with Al that generate binding sites for isolated and low-nuclearity metal site ensembles. Metal sites can become solvated and mobilized during reaction, facilitating interactions among sites that change their nuclearity and function. Such intersite communication can be regulated by the zeolite support, resulting in non-single-site and potentially non-mean-field kinetic behavior arising from mechanisms of catalytic action that combine elements of those canonically associated with homogeneous and heterogeneous catalysis. We discuss recent literature examples that document dynamic active site behavior in metal-zeolites and outline methodologies to identify and interpret such behavior. We conclude with our outlook on future research directions to develop this evolving branch of catalysis science and harness it for practical applications. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 12 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Study of Pc5 compressional waves by MMS observations

<p>Pc5 compressional waves are frequently observed in the outer magnetosphere with mirror mode features. Due to the limited spatial coverage of spacecraft, their overall structure is still poorly understood. In this work, the wave structure and motion characteristics are statistically investigated based on the MMS data from September to October 2015. During this time period, the apogees of the MMS spacecraft were located in the outer dusk magnetosphere, and the spacecraft has regular tetrahedral configuration that facilitates the application of multi-spacecraft analysis techniques. The magnetic trough boundaries are identified, and their normal direction, current density and velocity of these boundaries are calculated. We found that the magnetic trough has a magnetic bottle topology along the field line. In the r-a plane, the two boundaries has an open angle toward the radial direction.The boundaries mainly move sunward in the GSE XY plane with average speed of ~26km/s. The poloidal Alfven mode is found to be coupling with the compressional mode oscillation. It suggests that our observations could be explained by the theory of drift Alfven ballooning mirror instability.</p>

Monitoring and Analysis of Early Heart Structure of Fetus in Gynecology and Obstetrics Based on Ultrasound Image

As the core organ of cardiovascular system, fetal heart plays a very important role. With the development of pregnancy, the early fetal heart rate tends to mature, and the corresponding cardiac function tends to mature and stable. But the fetal heart is very fragile during pregnancy. Various diseases during pregnancy directly lead to fetal heart growth restriction, and even lead to fetal heart function damage. Ultrasound image diagnosis is one of the most important diagnostic methods in medical imaging. It is of great significance to detect the early heart structure of the fetus in gynecology and obstetrics. It can detect the early fetal heart in real time and noninvasively. However, the traditional ultrasonic image detection has many disadvantages in the process of application, such as many noise points, low performance of processing algorithm, which to some extent affects the detection performance of ultrasonic image detection in the detection of fetal heart structure in gynecology and obstetrics. Based on the above problems, this paper proposes an adaptive detection algorithm of superimposed moving image based on ultrasonic image detection, which can accurately extract and analyze fetal heart region when the signal-to-noise ratio of ultrasonic image sequence is low. The average anisotropy algorithm is also proposed innovatively in this paper. In order to predict the structure of fetal heart more accurately, the active heart model combining fetal heart structure and motion information is considered in the actual analysis process. Experiments show that the accuracy error of the algorithm is less than 11 pixels.