scholarly journals Assembly prestress and its variation in different water depths when applied to the active elements of a flextensional transducer

2004 ◽  
Vol 53 (2) ◽  
pp. 498
Author(s):  
He Xi-Ping ◽  
Li Bin
Keyword(s):  
Active Elements ◽  
Flextensional Transducer ◽  
Water Depths

RENDIMENTO DE CULTIVARES DE CAUPI (Vigna unguiculata L Walp.) SUBMETIDAS À DIFERENTES LÂMINAS DE IRRIGAÇÃO

Irriga ◽  
1999 ◽  
Vol 4 (3) ◽  
pp. 139-144 ◽  
Author(s):  
Gianini Peixoto Bezerra Lima ◽  
José Vanglesio de Aguiar ◽  
Raimundo Nonato Távora Costa ◽  
Vital Pedro da Silva Paz
Keyword(s):  
Vigna Unguiculata ◽  
Irrigation System ◽  
Northeast Brazil ◽  
Marginal Product ◽  
Applied Water ◽  
Cowpea Cultivars ◽  
The North ◽  
Significant Difference ◽  
Caixa Postal ◽  
Water Depths

RENDIMENTO DE CULTIVARES DE CAUPI (Vigna unguiculata L Walp.) SUBMETIDAS À DIFERENTES LÂMINAS DE IRRIGAÇÃO1       Gianini Peixoto Bezerra Lima José Vanglesio de Aguiar Raimundo Nonato Távora Costa Universidade Federal do Ceará – Departamento de Engenharia Agrícola. Campus do Pici. Bloco 804. CEP 60455-760 – Fortaleza-CE Vital Pedro da Silva Paz Escola Superior de Agricultura Luiz de Queiroz – Departamento de Engenharia Rural, bolsista da FAPESP. Av. Pádua Dias, 11 – Caixa Postal 11. 13418-900 – Piracicaba-SP       1 RESUMO       O caupi é um dos cultivos mais tradicionais do Norte e Nordeste do Brasil, constituindo alimento básico nestas regiões. Com este trabalho foi possível estabelecer relações entre a quantidade de água aplicada e produtividade de grãos, para três variedades de feijão caupi submetidas a diferentes lâminas de água. Para caracterização das lâminas de água foi utilizado um sistema de irrigação por aspersão convencional em linha. O controle da irrigação foi realizado a partir de tensiômetros instalados à 15 cm de profundidade. Os resultados mostraram que: i) a cultivar João Paulo II apresentou melhores resultados de produtividade para as lâminas de água aplicadas que variaram de T1 = 291,8 mm a T5 = 141,2 mm; ii) sob condições de reduzida disponibilidade de água, ou seja, menor lâmina aplicada, não ocorreu diferença estatística  para a produtividade entre as cultivares estudadas; e iii) para as condições do estudo, a cultivar Setentão apresentou a menor taxa de redução do produto marginal.       UNITERMOS: caupi, irrigação, função de produção       LIMA, G. P. B., AGUIAR, J. V., COSTA, R. N. T., PAZ, V. P. S. Responses OF cowpea cultivars (Vigna unguiculata L Walp) at differents irrigation deficits     2 ABSTRACT       The caupi is one of the most traditional cultivation of the north and northeast - Brazil, constituting a basic food in these areas. With this work it was possible to establish relationships between the amount of water applied and productivity of grains, for three caupi varieties submitted to different irrigation sheets. To diferentiate water depths in the irrigation system, the aspersion in line was used. The control of the irrigation was accomplished using tensiometers installed to 15 cm of depth. The results showed that: i) the João Paulo II variety presented better productivity for the applied water depths; ii) under reduced conditions of water avai lability for study conditions, these was no significant difference in the productivity reached among the cultivars studied; and iii) for the conditions of the study, the variety Setentão presented the smallest rate of reduction of the marginal product.       KEYWORDS: cowpea, irrigation, production function  

MAPPING TIDAL CURRENTS AND RESIDUAL CURRENTS BY USE OF COASTAL ACOUSTIC TOMOGRAPHY

2017 ◽  
Author(s):  
Xiao-Hua Zhu ◽  
Xiao-Hua Zhu ◽  
Ze-Nan Zhu ◽  
Ze-Nan Zhu ◽  
Xinyu Guo ◽  
...  
Keyword(s):  
Shallow Water ◽  
Shallow Water Equations ◽  
Mean Amplitude ◽  
Momentum Equation ◽  
Tidal Currents ◽  
Acoustic Tomography ◽  
Mean Values ◽  
Residual Currents ◽  
Water Depths ◽  
Deep Area

A coastal acoustic tomography (CAT) experiment for mapping the tidal currents in the Zhitouyang Bay was successfully carried out with seven acoustic stations during July 12 to 13, 2009. The horizontal distributions of tidal current in the tomography domain are calculated by the inverse analysis in which the travel time differences for sound traveling reciprocally are used as data. Spatial mean amplitude ratios M2 : M4 : M6 are 1.00 : 0.15 : 0.11. The shallow-water equations are used to analyze the generation mechanisms of M4 and M6. In the deep area, velocity amplitudes of M4 measured by CAT agree well with those of M4 predicted by the advection terms in the shallow water equations, indicating that M4 in the deep area where water depths are larger than 60 m is predominantly generated by the advection terms. M6 measured by CAT and M6 predicted by the nonlinear quadratic bottom friction terms agree well in the area where water depths are less than 20 m, indicating that friction mechanisms are predominant for generating M6 in the shallow area. Dynamic analysis of the residual currents using the tidally averaged momentum equation shows that spatial mean values of the horizontal pressure gradient due to residual sea level and of the advection of residual currents together contribute about 75% of the spatial mean values of the advection by the tidal currents, indicating that residual currents in this bay are induced mainly by the nonlinear effects of tidal currents.

Segregation and speciation in the Neogene planktonic foraminiferal clade Globoconella

Paleobiology ◽  
1999 ◽  
Vol 25 (3) ◽  
pp. 383-395 ◽  
Author(s):  
Cynthia E. Schneider ◽  
James P. Kennett
Keyword(s):  
Morphological Evolution ◽  
Evolutionary Divergence ◽  
Clinal Variation ◽  
Near Surface ◽  
Surface Warming ◽  
Isotopic Analyses ◽  
Oxygen Isotopic ◽  
Morphological Differences ◽  
Middle Pliocene ◽  
Water Depths

The origin of the Neogene planktonic foraminifer Globorotalia (Globoconella) pliozea in the subtropical southwest Pacific has been attributed to its isolation resulting from intensification of the Subtropical Divergence (Tasman Front). Oxygen isotopic analyses suggest that, although the Subtropical Divergence may have played a role, the evolution of Gr. (G.) pliozea was facilitated by depth segregation of Gr. (G.) conomiozea morphotypes (low and high conical) during an interval of near-surface warming and increasing thermal gradient. Oxygen isotopic analyses suggest that low conical morphotypes of Gr. (G.) conomiozea inhabited greater depths than high conical morphotypes. Low conical forms of Gr. (G.) conomiozea are considered ancestral to the low conical species, Gr. (G.) pliozea. Oxygen isotopes indicate that Gr. (G.) pliozea inhabited greater depths than its ancestor, Gr. (G.) conomiozea.These data are consistent with depth-parapatric and depth-allopatric models, but not with a sympatric model of speciation. In the allopatric model, reproduction at different water depths acts as a barrier between morphotypes. In the parapatric model, clinal variation along a depth gradient acts as a barrier between morphotypes living at the limits of the gradient. Depth segregation in both models results in genetic isolation and evolutionary divergence. Our data support a correlation between morphological evolution and habitat changes in the Globoconella clade, implying separation of populations as a driving force for morphological evolution.Ecological segregation of morphotypes and species may be related to morphology (height of the conical angle), based on the data from Gr. (G.) conomiozea and Gr. (G.) pliozea. However, morphological differences alone do not necessarily produce depth differences. Large morphological differences between Gr. (G.) pliozea and closely related Gr. (G.) puncticulata did not result in isotopic and therefore depth differences between these species. These species coexisted at the same water depths for nearly 1 m.y. Thus, it is unlikely that the extinction of Gr. (G.) pliozea in the middle Pliocene resulted from competition with Gr. (G.) puncticulata, as previously suggested.

scholarly journals An Improved Method for Energy and Resource Assessment of Waves in Finite Water Depths

Energies ◽  
2017 ◽  
Vol 10 (8) ◽  
pp. 1188 ◽  
Author(s):  
Wanan Sheng ◽  
Hui Li ◽  
Jimmy Murphy
Keyword(s):  
Resource Assessment ◽  
Improved Method ◽  
Water Depths

Strengthening mechanism of Si, V and Ti atoms to the Ag/AlN interface: a study from first-principles calculations

2020 ◽  
Vol 22 (46) ◽  
pp. 27433-27440
Author(s):  
Wenshan Bian ◽  
Runlin Li ◽  
Weibing Guo ◽  
Haitao Xue ◽  
Xiaoming Zhang
Keyword(s):  
First Principles ◽  
Strengthening Mechanism ◽  
Interfacial Bonding ◽  
First Principles Calculations ◽  
Active Elements

Active elements play key roles in improving the interfacial bonding between Ag-based fillers and AlN ceramics.

scholarly journals Nonlinear vibrations and time delay control of an extensible slowly rotating beam

2020 ◽  
Author(s):  
Jerzy Warminski ◽  
Lukasz Kloda ◽  
Jaroslaw Latalski ◽  
Andrzej Mitura ◽  
Marcin Kowalczuk
Keyword(s):  
Time Delay ◽  
Control Strategies ◽  
Vibration Reduction ◽  
Least Action ◽  
Active Elements ◽  
Principle Of Least Action ◽  
Second Mode ◽  
Delay Control ◽  
Speed Range ◽  
System With Time Delay

AbstractNonlinear dynamics of a rotating flexible slender beam with embedded active elements is studied in the paper. Mathematical model of the structure considers possible moderate oscillations thus the motion is governed by the extended Euler–Bernoulli model that incorporates a nonlinear curvature and coupled transversal–longitudinal deformations. The Hamilton’s principle of least action is applied to derive a system of nonlinear coupled partial differential equations (PDEs) of motion. The embedded active elements are used to control or reduce beam oscillations for various dynamical conditions and rotational speed range. The control inputs generated by active elements are represented in boundary conditions as non-homogenous terms. Classical linear proportional (P) control and nonlinear cubic (C) control as well as mixed ($$P-C$$ P - C ) control strategies with time delay are analyzed for vibration reduction. Dynamics of the complete system with time delay is determined analytically solving directly the PDEs by the multiple timescale method. Natural and forced vibrations around the first and the second mode resonances demonstrating hardening and softening phenomena are studied. An impact of time delay linear and nonlinear control methods on vibration reduction for different angular speeds is presented.

scholarly journals Microplastic contamination of the drilling bivalve Hiatella arctica in Arctic rhodolith beds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Teichert ◽  
Martin G. J. Löder ◽  
Ines Pyko ◽  
Marlene Mordek ◽  
Christian Schulbert ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Water Depth ◽  
The Arctic ◽  
Polymer Composition ◽  
Bivalve Species ◽  
Filter Feeder ◽  
Hiatella Arctica ◽  
Long Term Consequences ◽  
Water Depths

AbstractThere is an increasing number of studies reporting microplastic (MP) contamination in the Arctic environment. We analysed MP abundance in samples from a marine Arctic ecosystem that has not been investigated in this context and that features a high biodiversity: hollow rhodoliths gouged by the bivalve Hiatella arctica. This bivalve is a filter feeder that potentially accumulates MPs and may therefore reflect MP contamination of the rhodolith ecosystem at northern Svalbard. Our analyses revealed that 100% of the examined specimens were contaminated with MP, ranging between one and 184 MP particles per bivalve in samples from two water depths. Polymer composition and abundance differed strongly between both water depths: samples from 40 m water depth showed a generally higher concentration of MPs and were clearly dominated by polystyrene, samples from 27 m water depth were more balanced in composition, mainly consisting of polyethylene, polyethylene terephthalate, and polypropylene. Long-term consequences of MP contamination in the investigated bivalve species and for the rhodolith bed ecosystem are yet unclear. However, the uptake of MPs may potentially impact H. arctica and consequently its functioning as ecosystem engineers in Arctic rhodolith beds.

scholarly journals Recognize Yourself—Innate Sensing of Non-LTR Retrotransposons

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 94
Author(s):  
Justine Lagisquet ◽  
Kilian Zuber ◽  
Thomas Gramberg
Keyword(s):  
Pattern Recognition ◽  
Nucleic Acid ◽  
Autoimmune Diseases ◽  
Ltr Retrotransposons ◽  
Autoinflammatory Disorders ◽  
Protective Measures ◽  
Active Elements ◽  
Enhanced Expression ◽  
Long Interspersed Element

Although mobile genetic elements, or transposons, have played an important role in genome evolution, excess activity of mobile elements can have detrimental consequences. Already, the enhanced expression of transposons-derived nucleic acids can trigger autoimmune reactions that may result in severe autoinflammatory disorders. Thus, cells contain several layers of protective measures to restrict transposons and to sense the enhanced activity of these “intragenomic pathogens”. This review focuses on our current understanding of immunogenic patterns derived from the most active elements in humans, the retrotransposons long interspersed element (LINE)-1 and Alu. We describe the role of known pattern recognition receptors in nucleic acid sensing of LINE-1 and Alu and the possible consequences for autoimmune diseases.

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