Dimerized ground states in spin-S frustrated systems

We study a family of frustrated anti-ferromagnetic spin-$S$ systems with a fully dimerized ground state. This state can be exactly obtained without the need to include any additional three-body interaction in the model. The simplest members of the family can be used as a building block to generate more complex geometries like spin tubes with a fully dimerized ground state. After present some numerical results about the phase diagram of these systems, we show that the ground state is robust against the inclusion of weak disorder in the couplings as well as several kinds of perturbations, allowing to study some other interesting models as a perturbative expansion of the exact one. A discussion on how to determine the dimerization region in terms of quantum information estimators is also presented. Finally, we explore the relation of these results with a the case of the a 4-leg spin tube which recently was proposed as the model for the description of the compound Cu$_2$Cl$_4$D$_8$C$_4$SO$_2$, delimiting the region of the parameter space where this model presents dimerization in its ground state.Comment: 10 pages, 9 figure

Phase diagram study of a dimerized spin-S zig-zag ladder

The phase diagram of a frustrated spin-$S$ zig-zag ladder is studied through different numerical and analytical methods. We show that for arbitrary $S$, there is a family of Hamiltonians for which a fully-dimerized state is an exact ground state, being the Majumdar-Ghosh point a particular member of the family. We show that the system presents a transition between a dimerized phase to a N\'eel-like phase for $S=1/2$, and spiral phases can appear for large $S$. The phase diagram is characterized by means of a generalization of the usual Mean Field Approximation (MFA). The novelty in the present implementation is to consider the strongest coupled sites as the unit cell. The gap and the excitation spectrum is analyzed through the Random Phase Approximation (RPA). Also, a perturbative treatment to obtain the critical points is discussed. Comparisons of the results with numerical methods like DMRG are also presented.Comment: 14 pages, 6 figures. Some typos were corrected, and notation was clarifie

Desempenho de genótipos de arroz irrigado em Mato Grosso do Sul.

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Monitoring of an embankment dam in southern Spain based on Sentinel-1 Time-series InSAR

Sentinel-1A/B data were freely provided by ESA through Copernicus Programme. Data have been processed by SARPROZ (Copyright (c) 2009-2020 Daniele Perissin). The satellite orbits are from ESA Quality Control Group of Sentinel-1. Research was supported by: (a) ESA Research and Service Support for providing hardware resources employed in this work, (b) ReMoDams project ESP2017-89344-R (AEI/FEDER, UE) from Spanish Ministry of Economy, Industry and Competitiveness, PAIUJA-2019/2020 and CEACTEMA from University of Jaen (Spain), and RNM-282 research group from the Junta de Andalucia (Spain), (c) ERDF through the Operational Programme for Competitiveness and Internationalisation -COMPETE 2020 Programme within project >, and by National Funds through the FCT -Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) as part of project UID/EEA/50014/2013, (d) The Ministry of Education, Youth and Sports from the National Programme of Sustainability (NPU II) project > (Czech Republic), and (e) Slovak Grant Agency VEGA under projects No. 2/0100/20.Deformation monitoring is a common practice in most of dams to ensure their structural health and safety status. Systematic monitoring is frequently carried out by means of geotechnical sensors and geodetic techniques that, although very precise an accurate, can be time-consuming and economically costly. Remote sensing techniques are proved to be very effective in assessing deformation. Changes in the structure, shell or associated infrastructures of dams, including adjacent slopes, can be efficiently recorded by using satellite Synthetic Aperture Radar Inteferometry (InSAR) techniques, in particular, Muti-Temporal InSAR time-series analyses. This is a mature technology nowadays but not very common as a routine procedure for dam monitoring. Today, thanks to the availability of spaceborne satellites with high spatial resolution SAR images and short revisit times, this technology is a powerful cost-effective way to monitor millimeter-level displacements of the dam structure and its surroundings. What is more, the potential of the technique is increased since the Copernicus C-band SAR Sentinel-1 satellites are in orbit, due to the high revisit time of 6 days and the free data availability. ReMoDams is a Spanish research project devoted to provide the deformation monitoring of several embankments dams using advances time-series InSAR techniques. One of these dams is The Arenoso dam, located in the province of Cordova (southern Spain). This dam has been monitored using Sentinel-1 SAR data since the beginning of the mission in 2014. In this paper, we show the processing of 382 SLC SAR images both in ascending and descending tracks until March 2019. The results indicate that the main displacement of the dam in this period is in the vertical direction with a rate in the order of -1 cm/year in the central part of the dam body.ESA Research and ServiceReMoDams project (AEI/FEDER, UE) from Spanish Ministry of Economy, Industry and Competitiveness ESP2017-89344-RCEACTEMA from University of Jaen (Spain)Junta de Andalucia European Commission RNM-282ERDF through the Operational Programme for Competitiveness and Internationalisation -COMPETE 2020 Programme POCI-01-0145FEDER-006961National Funds through the FCT -Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) UID/EEA/50014/2013Ministry of Education, Youth and Sports from the National Programme of Sustainability (NPU II) project "IT4Innovations excellence in science" (Czech Republic) LQ1602Vedecka grantova agentura MSVVaS SR a SAV (VEGA) 2/0100/20PAIUJA-2019/202

Avaliação de cultivares de soja no município de Querência-MT.

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CFD Analysis of Biologically-Inspired Marine Propulsors

In the present work, the design and testing of two propulsion mechanisms which emulate fish swimming are presented. The motivation comes from the high effi ciency and maneuverality that fi sh demonstrate over conventional rotary propellers. In order to know the fl uid fl ow pattern in detail, a 3D CFD model was developed. Details of the velocity and pressure fi elds were obtained, as well as the hydrodynamic forces, cruising velocity, power and effi ciency. The results obtained using this CFD model were validated with the experimental prototypes, obtaining a reasonable agreement. Once validated, the CFD model was used to analyze several confi gurations of the propelling fi n, obtaining that thunniform swimming mode is the most effi cient

Produtividade do algodoeiro em rotação com soja no sistema plantio direto.

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O algodoeiro em rotação com a soja no sistema plantio direto.

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Cultivares, densidades e espaçamentos entre fileiras na cultura do algodoeiro em Mato Grosso do Sul.

Este trabalho teve como objetivo avaliar o comportamento de quatro cultivares de algodoeiro em três locais do Estado de Mato Grosso do Sul, utilizando-se espaçamentos entre fileiras de 0,30; 0,60; 0,90 e 1,20 m, nas densidades de 4, 8, 12 e 16 plantas m-1.bitstream/item/38777/1/BP200523.pd

BRS Aroeira - Nova cultivar de algodoeiro para Mato Grosso do Sul.

bitstream/item/24861/1/COT200255.pdfDocumento on-line