Design, Modeling, and Motion Analysis of a Novel Fluid Actuated Spherical Rolling Robot

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Seyed Amir Tafrishi ◽  
Mikhail Svinin ◽  
Esmaeil Esmaeilzadeh ◽  
Motoji Yamamoto
Keyword(s):  
Forward Direction ◽  
Motion Patterns ◽  
Design Specifications ◽  
The Core ◽  
D’Alembert Principle ◽  
Circular Pipes ◽  
Fluid Properties ◽  
Spherical Mobile Robot ◽  
The Given ◽  
Rolling Robot

This paper studies a novel fluid actuated system for a spherical mobile robot. The robot’s mechanism consists of two essential parts: circular pipes to lead spherical moving masses (cores) and an internal driving unit to propel the cores. The spherical shell of the robot is rolled by displacing the cores in the pipes filled with fluid. First, we describe the structure of the robot and derive its nonlinear dynamics using the D’Alembert principle. Next, we model the internal driving unit that actuates the core inside the pipe. The simulated driving unit is studied with respect to three important parameters—the input motor torque, the actuator size, and the fluid properties. The overall model of the robot is then used for analyzing motion patterns in the forward direction. Analytical studies show that the modeled robot can be implemented under the given design specifications.

scholarly journals On the formation and stability of fermionic dark matter halos in a cosmological framework

2020 ◽  
Author(s):  
Carlos R Argüelles ◽  
Manuel I Díaz ◽  
Andreas Krut ◽  
Rafael Yunis
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Space Distribution ◽  
Coarse Grained ◽  
Dark Matter Halos ◽  
The Core ◽  
The Galaxy ◽  
Gravitating Systems ◽  
The Given ◽  
First Time

Abstract The formation and stability of collisionless self-gravitating systems is a long standing problem, which dates back to the work of D. Lynden-Bell on violent relaxation, and extends to the issue of virialization of dark matter (DM) halos. An important prediction of such a relaxation process is that spherical equilibrium states can be described by a Fermi-Dirac phase-space distribution, when the extremization of a coarse-grained entropy is reached. In the case of DM fermions, the most general solution develops a degenerate compact core surrounded by a diluted halo. As shown recently, the latter is able to explain the galaxy rotation curves while the DM core can mimic the central black hole. A yet open problem is whether this kind of astrophysical core-halo configurations can form at all, and if they remain stable within cosmological timescales. We assess these issues by performing a thermodynamic stability analysis in the microcanonical ensemble for solutions with given particle number at halo virialization in a cosmological framework. For the first time we demonstrate that the above core-halo DM profiles are stable (i.e. maxima of entropy) and extremely long lived. We find the existence of a critical point at the onset of instability of the core-halo solutions, where the fermion-core collapses towards a supermassive black hole. For particle masses in the keV range, the core-collapse can only occur for Mvir ≳ E9M⊙ starting at zvir ≈ 10 in the given cosmological framework. Our results prove that DM halos with a core-halo morphology are a very plausible outcome within nonlinear stages of structure formation.

Fluid Mechanics Research and Engineering Application in Non-Newtonian Fluid Systems

1964 ◽  
Vol 4 (01) ◽  
pp. 56-66 ◽  
Author(s):  
L.L. Melton ◽  
W.T. Malone
Keyword(s):  
Newtonian Fluid ◽  
Pilot Plant ◽  
Scale Up ◽  
Engineering Application ◽  
Unsteady State ◽  
Hydraulic Behavior ◽  
Circular Pipes ◽  
Fluid Systems ◽  
Fluid Properties ◽  
Pilot Plant Study

Abstract Fluid mechanics research conducted with non-Newtonian fluid systems now permits prediction of the behavior of these fluid systems in both laminar and turbulent modes of flow through circular pipes. Present work concerns non-Newtonian fluid systems currently used in the hydraulic fracturing process. During fracturing treatments, an unsteady-state condition may frequently be encountered arising from' the reaction rate of a chemical additive. This condition must be evaluated in order to predict the actual behavior of a particular fluid during field application. Design and operation of the apparatus used to determine fluid-flow behavior permit obtaining data under such non-equilibrium conditions. This paper shows methods used to obtain rheology measurements, develop hydraulic relationships and evaluate chemical reactions producing unsteady-state conditions. Engineering application of this research is illustrated by employing measured rheological values and developed hydraulic relationships to produce frictional pressure loss (psi/100 ft) vs flow rate (bbl/min) charts of common tubing and casing sizes for an example fracturing fluid. How these charts and chemical reaction rate information are then combined to predict actual turbulent hydraulic behavior during unsteady-state field conditions is also discussed. Introduction Many fluids used in hydraulic fracturing contain chemical additives which impart non-Newtonian fluid properties that may drastically alter their hydraulic behavior. Equally drastic alteration in wellhead pressure, injection rate and hydraulic horsepower requirement may result from these fluid properties. Prior research conducted to relate non-Newtonian fluid properties with hydraulic behavior has not as yet produced a universal relationship, particularly for the turbulent flow region. Which of the many possible non-Newtonian fluid properties is responsible has not been conclusively established. A systematic description, suggested by Metzner, of the many possible non-Newtonian fluid properties exhibited by real - fluid behavior, and a current discussion of theoretical and applied aspects of non-Newtonian fluid technology can be found in Handbook of Fluid Dynamics. Little or no research has previously been attempted with fluids exhibiting time - dependent properties. Addition of chemicals during a fracturing treatment is often accomplished by continuously mixing and displacing the fluid. This produces a time-dependent effect or unsteady-state condition while the fluid is progressing through surface and wellbore conductors. This condition is due to solution or chemical reaction of the additive. Considerable departure from conventional methods of obtaining and interpreting data was found necessary to consider these conditions. Therefore methods were developed to obtain hydraulic behavior information under these complex, unsteady-state conditions. Relationships presented in this paper to predict hydraulic behavior of non-Newtonian fluids in circular pipes were obtained by constructing and operating a small pipeline apparatus in the manner of a pilot-plant study. These relationships are suggested as scale-up equations and are not proposed as fundamental rheological parameters. While perhaps deficient from a fundamental research viewpoint, a pilot-plant study does permit the determination and convenient evaluation of variables pertinent to a process. A pilot-plant study can result in a valid engineering application procedure even when fundamental relationships are still undefined. An excellent series of articles by Bowen has appeared in the chemical engineering literature. These give a thorough review of proposed hydraulic relationships and their limitations for non-Newtonian fluid behavior in circular pipes. A graphical method is presented to scale up data for a fluid exhibiting an anomalous hydraulic behavior in the turbulent flow region. Considerable assistance has been obtained from these articles to interpret the anomalous behavior noted during this investigation. These articles also provided assurance that a pilot plant is a practical approach to evaluate the hydraulic behavior of non-Newtonian fracturing fluids. SPEJ P. 56ˆ

scholarly journals Mind mapping as a tool of teaching English vocabulary at transport university

2021 ◽  
Vol 295 ◽  
pp. 05021
Author(s):  
Oksana Marunevich ◽  
Elmira Shefieva ◽  
Olga Bessarabova
Keyword(s):  
Educational Process ◽  
Control Group ◽  
Teaching English ◽  
Mind Mapping ◽  
New Words ◽  
The Core ◽  
Mind Maps ◽  
The Given ◽  
Core Problem ◽  
Experimental Group

The core problem of teaching English as a second language at transport university is students’ poor knowledge of vocabulary. Current solutions to the given problem such as providing word explanations and repetitive practices are ineffective. We strongly believe that the mindmapping technique proposed by Tony Buzan as a note-taking method is a novel, yet an extremely potent tool that aids students in enlarging their professional word stock by associating new vocabulary to their existing knowledge using colors, images, symbols, etc. As might have been expected, the findings of our study point towards the idea that the strong visual appeal of mind maps created by easy-to-use software boosted the educational process and helped students of the experimental group memorize more new words in contrast to students of the control group.

scholarly journals A Review of Charge Pump Topologies for the Power Management of IoT Nodes

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 480 ◽  
Author(s):  
Andrea Ballo ◽  
Alfio Dario Grasso ◽  
Gaetano Palumbo
Keyword(s):  
Internet Of Things ◽  
Power Management ◽  
Energy Harvester ◽  
State Of The Art ◽  
Charge Pump ◽  
The State ◽  
Data Driven ◽  
Design Specifications ◽  
The Given ◽  
Insight Into

With the aim of providing designer guidelines for choosing the most suitable solution, according to the given design specifications, in this paper a review of charge pump (CP) topologies for the power management of Internet of Things (IoT) nodes is presented. Power management of IoT nodes represents a challenging task, especially when the output of the energy harvester is in the order of few hundreds of millivolts. In these applications, the power management section can be profitably implemented, exploiting CPs. Indeed, presently, many different CP topologies have been presented in literature. Finally, a data-driven comparison is also provided, allowing for quantitative insight into the state-of-the-art of integrated CPs.

Study of Conceptual Design of the Extension Method for Mechanical Products

2002 ◽  
Author(s):  
Yanwei Zhao ◽  
Guoxian Zhang
Keyword(s):  
Conceptual Design ◽  
Design Method ◽  
Extension Method ◽  
The Core ◽  
Function Decomposition ◽  
Core Technology ◽  
Mechanical Products ◽  
Function Expression ◽  
The Given ◽  
Important Significance

On the foundation summing up existing intelligent conceptual design method, this paper puts forward the research content, characters, path, and method of the conceptual design of extension for mechanical products. This paper rounds the core technology of intelligent conceptual design to research the modeling method of extension design in function-principle-layout-configuration. It includes the function expression, function decomposition and synthesis, function illation and decision. The computers are utilized to simulate the human dialectic thought when resolve problems in this method. The given example shows that the extension method has been applied in the field of conceptual design for mechanical products. This method has important significance to resolve the bottleneck problem of theory studying and engineering realizing of intelligent CAD.

GENERALIZED MELZAK'S CONSTRUCTION IN THE STEINER TREE PROBLEM

2002 ◽  
Vol 12 (06) ◽  
pp. 481-488 ◽  
Author(s):  
JIA F. WENG
Keyword(s):  
Steiner Tree ◽  
Euclidean Plane ◽  
Steiner Tree Problem ◽  
Minimal Tree ◽  
Steiner Minimal Tree ◽  
The Core ◽  
Steiner Minimal Trees ◽  
Minimum Networks ◽  
Set Of Points ◽  
The Given

For a given set of points in the Euclidean plane, a minimum network (a Steiner minimal tree) can be constructed using a geometric method, called Melzak's construction. The core of the Melzak construction is to replace a pair of terminals adjacent to the same Steiner point with a new terminal. In this paper we prove that the Melzak construction can be generalized to constructing Steiner minimal trees for circles so that either the given points (terminals) are constrained on the circles or the terminal edges are tangent to the circles. Then we show that the generalized Melzak construction can be used to find minimum networks separating and surrounding circular objects or to find minimum networks connecting convex and smoothly bounded objects and avoiding convex and smoothly bounded obstacles.

scholarly journals The Role of English in the Acquisition of Intercultural Competence by Russian Students

2007 ◽  
Vol 3 (1 (3)) ◽  
pp. 77-83
Author(s):  
Valentina Golysheva
Keyword(s):  
Social Behavior ◽  
21St Century ◽  
Intercultural Competence ◽  
Core Values ◽  
Special Significance ◽  
The Core ◽  
The Given ◽  
Polite Speech

The article illustrates the interaction of the language and social behavior which has acquired special significance in the 21st century, conditioned by the development of various cultural links. Underlining the obstacles connected with the differences in the cultures and mentality of different nations in understanding the language, the author attaches importance to the investigation of the core values and ethics of the given nation. In case of England, the relevance of politeness in various forms of request and command becomes a priority.The article aims to introduce some of the mechanisms of polite command and request to Russian students of English. However, the focus of the investigation is on euphemism as an important element of polite speech.

scholarly journals LEXICAL MEANS OF VERBALIZATION OF THE ENGLISH CONCEPT HAIR

2021 ◽  
Author(s):  
N.M. Mikava
Keyword(s):  
Social Group ◽  
English Language ◽  
Body Hair ◽  
Facial Hair ◽  
The Core ◽  
The World ◽  
English Speaking ◽  
And Gender ◽  
Somatic Feature ◽  
The Given

The article is devoted to the consideration of the features of the verbalization of the concept HAIR in the English language. The purpose of the work is to examine the structure of the English concept HAIR as a fragment of the English-language picture of the world of the English-speaking society. The main attention is focused on the analysis of the language embodiment of the given concept in the naïve and professional varients of the picture of the world. The English concept HAIR is a fragment of the conceptual picture of the world, which is reflected in the language picture of the world, namely in its three fragments, verbalized by the constituents of the lexical-semantic groups, distinguished according to the somatic feature. They are head hair, facial hair, body hair. The analysis of the language and speech material showed that the structure of the English concept HAIR in the naive picture of the world is a three-component formation, which consists of a core, a nuclear zone and a periphery. The core includes such conceptual features as somatic and gender. The nuclear zone includes objective and various associative conceptual features, namely: age, thinness, protection, beauty, strength / success, value. The periphery of the concept consists of socially-identifying functions - professional, religious and social-group. The core of the concept HAIR in the professional picture of the world includes such conceptual features as somatic, gender, structure and development. The nuclear zone includes objective conceptual features, namely: health, age, protection. The periphery of the concept consists of professional, religious, and social-group social-identifying functions. Thus the periphery of the given concept in the two variants of the picture of the world is identical. The prospects for further research are seen in the consideration of the mentioned aspects of verbalization on the material of English artistic speech as well as professional discourse.

scholarly journals Overview on Image Captioning Techniques

2021 ◽  
Vol 9 (8) ◽  
pp. 1118-1123
Keyword(s):  
Computer Vision ◽  
Language Processing ◽  
Multimodal Learning ◽  
Image Captioning ◽  
Survey Paper ◽  
The Core ◽  
Deep Learning Neural Network ◽  
The Given ◽  
Source Of Information ◽  
Object Attribute

Image captioning is a process to assign a meaningful title for a given image with the help of Natural Language Processing (NLP) and Computer Vision techniques. Captioning of an image first need to identify object, attribute and relationship among these in image and second is to generate relevant description for the given image. So it require both NLP and Computer vision techniques to perform image captioning task. Due to complexity of finding relationship between the attribute of the object and its feature makes it a challenging task. Also for machine it is difficult to emulate human brain however researches have shown a prominent achievement in this field and made it easy to solve such problems. The foremost aim of this survey paper is to describe several methods to achieve the same, the core involvement of this paper is to categorise different existing approaches for image captioning, further discussed their subcategories of this method and classify them, also discussed some of their strength and limitations. This survey paper gives theoretical analysis of image captioning methods and defines some earlier and newly approach for image captioning. This survey paper is basically a source of information for researchers in order to get idea of different approaches that were developed so far in the field of image captioning. Key words : Computer Vision, Deep Learning, Neural Network, NLP, Image Captioning, Multimodal Learning.

scholarly journals The Core of the Activity Concept of Extend Didactic Unit (EDU) Technology in Teaching Geometry

2017 ◽  
Vol 6 (1) ◽  
pp. 71-76
Author(s):  
Ульянова ◽  
I. Ulyanova
Keyword(s):  
Scientific Knowledge ◽  
Logical Inference ◽  
The Core ◽  
Teaching Geometry ◽  
Technology In Teaching ◽  
The Subject ◽  
Subject Material ◽  
The Given

The core of the concept allows to characterize the specifics of any pedagogical concept and to enable the theoretical and logical inference of its key provisions. It is formed by the basic laws and principles of the concept as a system of scientific knowledge. The activity concept of the technology of extend didactic units (EDU) is based on the idea of an action enlargement, as a fundamental strategic component. Then one of the components of the core of the activity concept EDU, explaining the regularities of its functioning, is the system of an action enlargement as didactic units. The given paper is reveals the gradual construction of a final (noncomputer) model of system of this enlargement using the phased construction of the auxiliary models: informational and symbolic. Also the mechanism of an action enlargement based on this model is described. Thus the essence of the model and the mechanism of an enlargement are showed on the subject material of the school course of geometry.

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