scholarly journals EQUILIBRIUM CONDITIONS IN BEACH WAVE INTERACTION

1972 ◽  
Vol 1 (13) ◽  
pp. 62 ◽  
Author(s):  
H. Raman
Keyword(s):  
Wave Interaction ◽  
Experimental Results ◽  
Laboratory Studies ◽  
Regular Waves ◽  
Equilibrium Conditions ◽  
Wave Characteristics ◽  
New Criterion ◽  
Constant Characteristics ◽  
Stable Points

Laboratory studies were conducted in an attempt to find out a relationship between beach and wave characteristics when equilibrium conditions are reached in beach wave interaction for the simple case of regular waves acting normal to the beach. Experimental results indicate the existence of stable points on beach profiles where the coordinates of the profile do not change with time when waves of constant characteristics act on the beach. Emperical relationship between the wave and beach properties are proposed. A new criterion for classification of beach profiles is indicated.

Interaction of a Whirling Rotor with a Vibrating Stator across a Clearance Annulus

1968 ◽  
Vol 10 (1) ◽  
pp. 1-12 ◽  
Author(s):  
H. F. Black
Keyword(s):  
Dry Friction ◽  
Ball Bearing ◽  
Radial Symmetry ◽  
Experimental Results ◽  
Equilibrium Conditions ◽  
General Behaviour ◽  
Mass Unbalance ◽  
Jump Phenomena ◽  
Rotor Stator Interaction ◽  
Rotor Mass

Where a rotor runs within a clearance space, the clearance being comparable with rotor mass unbalance, the synchronous whirling behaviour of the rotor may be considerably affected by intermittent interaction with the stator at the clearance position. Discontinuity and jump phenomena may occur: in general, behaviour will be different with increasing speed from that with decreasing speed, and in either case zones may exist in which rotor-stator interaction is possible but not certain. In the analysis here presented, rotor and stator are regarded as linear multi-degree-of-freedom systems including damping; dry friction at the clearance space is taken into account. Discussion is limited to cases with radial symmetry, and interaction is assumed limited to the position of the clearance space. Polar receptances are used to establish equilibrium conditions with interaction, and speed zones are defined within which interaction may occur. Some hypothetical cases are fully explored, demonstrating that rotor-stator interactions may occur in a variety of forms and circumstances. Interactions with dry friction counterwhirling are also considered. Some experimental results on counterwhirl within a ball bearing are given and qualitatively compared with theory.

Wave Energy Hyperbaric Device for Electricity Production

2007 ◽  
Author(s):  
Segen F. Estefen ◽  
Paulo Roberto da Costa ◽  
Eliab Ricarte ◽  
Marcelo M. Pinheiro
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Experimental Results ◽  
Electricity Production ◽  
Scale Model ◽  
Small Scale ◽  
Regular Waves ◽  
Hyperbaric Chamber ◽  
Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

MAGNETOREOLOGICAL JOURNAL BEARING: EXPERIMENTAL RESULTS

2020 ◽  
Vol 3 ◽  
pp. 83-90
Author(s):  
A.S. FETISOV ◽  
V.O. TYURIN
Keyword(s):  
Experimental Study ◽  
Journal Bearing ◽  
Experimental Results ◽  
Measuring System ◽  
Information Measuring ◽  
Experimental Stand ◽  
Information Measuring System

The article presents the classification of magnetorheological devices. The classification of bearings of rotor machines is given. An experimental stand is described that includes a magnetorheological journal bearing. The information–measuring system of the experimental stand is presented. The results of experimental study is presented.

scholarly journals An Empirical Comparison of Portuguese and Multilingual BERT Models for Auto-Classification of NCM Codes in International Trade

2021 ◽  
Author(s):  
Roberta Rodrigues de Lima ◽  
Anita M. R. Fernandes ◽  
James Roberto Bombasar ◽  
Bruno Alves da Silva ◽  
Paul Crocker ◽  
...  
Keyword(s):  
International Trade ◽  
Specific Model ◽  
Experimental Results ◽  
Empirical Comparison ◽  
Correct Category ◽  
Fiscal Implications ◽  
Real Challenge

The classification of goods involved in international trade in Brazil is based on the Mercosur Common Nomenclature (NCM). The classification of these goods represents a real challenge due to the complexity involved in assigning the correct category codes especially considering the legal and fiscal implications of misclassification. This work focuses on the training of a classifier based on Bidirectional En-coder Representations from Transformers (BERT) for the tax classification of goods with NCM codes. In particular, this article presents results from using a specific Portuguese Language tuned BERT model as well results from using a Multilingual BERT. Experimental results justify the use of these models in the classification process and also that the language specific model has a slightly better performance.

scholarly journals THE DISTRIBUTION CONDITIONS, THE COMPOSITION AND STRUCTURE OF THE SOILS OF THE KHARKOV SUITE OF PALEOGENE OF THE SOUTHEAST OF BELARUS

2019 ◽  
Vol 14 (2) ◽  
pp. 60-73
Author(s):  
O. I. Galeznik ◽  
A. N. Galkin
Keyword(s):  
Statistical Data ◽  
Fine Sand ◽  
Soil Sampling ◽  
Laboratory Studies ◽  
Composition And Structure ◽  
The Republic ◽  
Size And Morphology ◽  
The City

The deposits of the Kharkov suite of Paleogene of Belarus are the soils formed at the turn of existence and regression of the last sea basin and the final establishment of the continental situation in the territory of the country. They are widely spread in the south of the republic and lie mostly at depths of 100–110 m. In the southeast of Belarus, along the valleys of large rivers, these soils often reach the surface. The latter predetermined their active use as the foundations of structures. This is especially pronounced in the city of Gomel, where a wide development of territories is currently underway, within which these soils lie at depths of less than 10 m. The purpose of the work is to characterize the conditions for the distribution of the soils of the Kharkov suite of Paleogene within the southeast of Belarus and to study the characteristics of their composition and structure. The work is based on the results of the author's field and laboratory studies, which included a description of the outcrops, pits, and well cores; soil sampling; determination of their chemical and mineral, granulometric and microaggregate compositions, moisture characteristics for the classification of clay soils, as well as the results of statistical data processing. The paper presents the typification of the soil strata of the Kharkov suite of Paleogene of the southeast of Belarus, which allowed us to isolate three characteristic sites that differ in terms of their distribution, depth, thickness of the strata and composition of the soils. Nine granulometric sand and clay differences within the isolated areas were identified. The study of chemical-mineral and granulometric compositions of soils made it possible to identify their significant changes, both in area and in the section, which is caused by confinement to various facies zones, frequent migration of the coastline, long and uneven erosion and glacier-exaction destruction. The interrelation of the mineral composition, size and morphology of sandy soil particles is analyzed, it is noted that in all their varieties medium and fine sand fractions differ in the greatest mineral diversity.

scholarly journals Kinetostatic analysis and solution classification of a class of planar tensegrity mechanisms

Robotica ◽  
2018 ◽  
Vol 37 (7) ◽  
pp. 1214-1224 ◽  
Author(s):  
P. Wenger ◽  
D. Chablat
Keyword(s):  
Static Equilibrium ◽  
Equilibrium Conditions ◽  
Geometric Conditions ◽  
Equilibrium Configurations ◽  
Groebner Base ◽  
Systematic Solution ◽  
Alternative Designs ◽  
Interesting Alternative ◽  
Solution Classification

SUMMARYTensegrity mechanisms are composed of rigid and tensile parts that are in equilibrium. They are interesting alternative designs for some applications, such as modeling musculo-skeleton systems. Tensegrity mechanisms are more difficult to analyze than classical mechanisms as the static equilibrium conditions that must be satisfied generally result in complex equations. A class of planar one-degree-of-freedom tensegrity mechanisms with three linear springs is analyzed in detail for the sake of systematic solution classifications. The kinetostatic equations are derived and solved under several loading and geometric conditions. It is shown that these mechanisms exhibit up to six equilibrium configurations, of which one or two are stable, depending on the geometric and loading conditions. Discriminant varieties and cylindrical algebraic decomposition combined with Groebner base elimination are used to classify solutions as a function of the geometric, loading, and actuator input parameters.

Application of the LDA Model to Semantic Annotation of Web-based English Educational Resources

2021 ◽  
Author(s):  
Wei Du ◽  
Haiyan Zhu ◽  
Teeraporn Saeheaw
Keyword(s):  
Topic Modeling ◽  
Basic Education ◽  
Semantic Annotation ◽  
Experimental Results ◽  
Educational Resources ◽  
Metadata Standard ◽  
Web Based ◽  
Teaching Content ◽  
Macroscopic Classification

Based on the LDA model, this paper builds a three-layer semantic model of Web English educational resources “document-topic-keyword”, models the semantic topics of resource documents, and obtains the semantic topics and keywords of document resources as the semantic labels of resources. The experimental results show that document LDA topic modeling is beneficial to the macroscopic classification of Web English educational resources. The experimental results show that LDA topic modeling of documents is useful for macroscopic cataloging of Web English educational resources, highlighting teaching priorities, difficulties, and interrelationships, while LDA modeling of teaching topics with the same teaching content expands the metadata generation method of resource description based on the basic education metadata standard and provides more information about the inherent characteristics of resources. The semantic information can be used to mine the semantic thematic features and detailed differences inherent in the resources, and the final performance analysis verifies the parallel computing advantages of the LDA model in a big data environment.

Efficient text feature extraction by integrating the average linkage and K-medoids clustering

2021 ◽  
pp. 2150151
Author(s):  
Dasong Sun
Keyword(s):  
Feature Extraction ◽  
Text Classification ◽  
Experimental Results ◽  
The Other ◽  
Central Feature ◽  
Number Of Clusters ◽  
Average Linkage ◽  
Text Feature

By clustering feature words, we can not only simplify the dimension of feature subsets, but also eliminate the redundancy of the feature. However, for a feature set with very large dimensions, the traditional [Formula: see text]-medoids algorithm is difficult to accurately estimate the value of [Formula: see text]. Moreover, the clustering results of the average linkage (AL) algorithm cannot be divided again, and the AL algorithm cannot be directly used for text classification. In order to overcome the limitations of AL and [Formula: see text]-medoids, in this paper, we combine the two algorithms together so as to be mutually complementary to each other. In particular, in order to meet the purpose of text classification, we improve the AL algorithm and propose the [Formula: see text] testing statistics to obtain the approximate number of clusters. Finally, the central feature words are preserved, and the other feature words are deleted. The experimental results show that the new algorithm largely eliminates the redundancy of the feature. Compared with the traditional TF-IDF algorithms, the performance of the text classification of the new algorithm is improved.

scholarly journals Nondestructive Evaluation of Solids Based on Deformation Wave Theory

2020 ◽  
Vol 10 (16) ◽  
pp. 5524
Author(s):  
Sanichiro Yoshida ◽  
Conor McGibboney ◽  
Tomohiro Sasaki
Keyword(s):  
Field Theory ◽  
Solitary Wave ◽  
Displacement Field ◽  
Wave Equations ◽  
Continuous Wave ◽  
Experimental Results ◽  
Electronic Speckle Pattern Interferometry ◽  
Wave Characteristics ◽  
Spatiotemporal Characteristics ◽  
Deformation Stage

The application of a recent field theory of deformation and fracture to nondestructive testing (NDT) is discussed. Based on the principle known as the symmetry of physical laws, the present field theory formulates all stages of deformation including the fracturing stage on the same theoretical basis. The formalism derives wave equations that govern the spatiotemporal characteristics of the differential displacement field of solids under deformation. The evolution from the elastic to the plastic stage of deformation is characterized by a transition from longitudinal (compression) wave to decaying longitudinal/transverse wave characteristics. The evolution from the plastic to the fracturing stage is characterized by transition from continuous wave to solitary wave characteristics. Further, the evolution from the pre-fracturing to the final fracturing stage is characterized by transition from the traveling solitary wave to stationary solitary wave characteristics. In accordance with these transitions, the criterion for deformation stage is defined as specific spatiotemporal characteristics of the differential displacement field. The optical interferometric technique, known as Electronic Speckle-Pattern Interferometry (ESPI), is discussed as an experimental tool to visualize those wave characteristics and the associated deformation-stage criteria. The wave equations are numerically solved for the elastoplastic stages, and the resultant spatiotemporal behavior of the differential displacement field is compared with the experimental results obtained by ESPI. Agreement between the experimental and numerical results validates the present methodology at least for the elastoplastic stages. The solitary wave characteristics in the fracturing stages is discussed based on the experimental results and dislocation theory.

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