Design of the Target Dump Injection Segmented (TDIS) in the framework of the High Luminosity Large Hadron Collider (HL-LHC) project

The High Luminosity Large Hadron Collider (HL-LHC) Project at CERN calls for increasing beam brightness and intensity. In this scenario, most equipment has to be redesigned and rebuilt. In particular, beam intercepting devices (such as dumps, collimators, absorbers and scrapers) have to withstand impact or scraping of the new intense HL-LHC beams without failure. Furthermore, minimizing the electromagnetic beam-device interactions is also a key design driver since they can lead to beam instabilities and excessive thermo-mechanical loading of devices. In this context, the present study assesses the conceptual design quality of the new LHC injection protection absorber, the Target Dump Injection Segmented (TDIS), from an electromagnetic and thermo-mechanical perspective. This contribution analyzes the thermo-mechanical response of the device considering two cases: an accidental beam impact scenario and another accidental scenario with complete failure of the RFcontacts. In addition, this paper presents the preliminary results from the simulation of the energy deposited by the two counter-rotating beams circulating in the device

Diagnosing order by disorder in quantum spin systems

In this paper we study the frustrated J1-J2 quantum Heisenberg model on the square lattice for J2 > 2J1, in a magnetic field. In this regime the classical system is known to have a degenerate manifold of lowest energy configurations, where standard thermal order by disorder occurs. In order to study its quantum version we use a path integral formulation in terms of coherent states. We show that the classical degeneracy in the plane transverse to the magnetic field is lifted by quantum fluctuations. Collinear states are then selected, in a similar pattern to that set by thermal order by disorder, leaving a Z2 degeneracy. A careful analysis reveals a purely quantum mechanical effect given by the tunneling between the two minima selected by fluctuations. The effective description contains two planar (XY -like) fields conjugate to the total magnetization and the difference of the two sublattice magnetizations. Disorder in either or both of these fields produces the locking of their conjugate observables. Furthermore, within this scenario we argue that the quantum state is close to a product state.Comment: 8 pages, 3 figure

Nitrogênio e regulador de crescimento no algodoeiro no sistema plantio direto.

bitstream/item/39666/1/PA-6-1998.pd

Algodoeiro em sistema plantio direto.

Tradicionalmente, para o cultivo do algodoeiro, o solo é preparado utilizando-se vários implementos e operações. Os implementos mais utilizados para o preparo do solo são: grade pesada (uma vez), grade leve (duas a três vezes) e, em muitos casos, ainda é utilizada uma grade intermediária. Este sistema de manejo leva à degradação das propriedades físicas, químicas e biológicas do solo e, paulatinamente, diminui o potencial produtivo do mesmobitstream/item/24415/1/COT2006118.pdfDocumento on-line

Espécies vegetais para cobertura de solo no cerrado de Mato Grosso.

A alternativa mais adequada às condições tropicais, no que tange ao manejo do solo, é o sistema plantio direto. Este fundamenta-se em programas de rotação de culturas e caracteriza-se pela semeadura em terreno coberto por palha e/ou plantas em crescimento e em ausência de preparo do solo, por tempo indeterminado (Hernani & Salton, 2001). Pelos resultados obtidos neste trabalho, são várias as espécies vegetais que podem ser utilizadas de forma isolada ou em consórcio para a produção de palha nas condições do cerrado de Mato Grosso.bitstream/item/24695/1/COT200597.pdfDocumento on-line

Adubação nitrogenada em cobertura e regulador de crescimento na cultura do algodoeiro em sistema plantio direto.

bitstream/item/39707/1/COT-05-1999.pd

Coastal bathymetry estimation using an ensemble of synthetic aperture radar images from Sentinel-1

In this study, coastal bathymetry is estimated with a wave ray-tracing algorithm using wave parameters retrieved from Synthetic Aperture Radar (SAR) images acquired by the Sentinel-1 satellites. The method relies on the long swell wave’s detection by SAR imagery and the wave’s properties adjustment to the underwater topography, which can be mathematically related using the linear dispersion relation. The ray-tracing algorithm tracks the shoaling waves until the wave breaking zone, using the wavelength and wave direction retrieved from the 2D directional spectra applied at consecutive sub-images. Then, by inverting the linear wave dispersion relationship, the depth is calculated based on the mean wavelength obtained for each sub-image and maintaining the wave period retrieved at the first offshore position, which is computed using a mean depth from an independent bathymetric source. The output of the algorithm is a bathymetric model that results from the interpolation of the depth computed at each tracking position to a uniform grid and the results are compared with bathymetric information from the General Bathymetric Chart of the Ocean. The use of a monthly ensemble of SAR images, instead of individual ones, to reproduce the bathymetry near Aveiro, Portugal, resulted in a smoother topography with lower relative errors, suggesting that the final bathymetric model retrieved from SAR should result from a combination of SAR images. The methodology presented here to infer the bathymetry using space-borne SAR imagery can be useful to retrieve the mean bottom topography (especially in remote areas where the traditional hydrographic surveying methods are not performed regularly) and to reproduce new underwater structures, such as banks, reefs or bars, which are important to detect for the safety of navigation.Peer Reviewe

Ultrasonographic evaluation of the supraspinous ligament in a series of ridden and unridden horses and horses with unrelated back pathology

Abstract Background Injury to the supraspinous ligament (SSL) is reported to cause back pain in the horse. The diagnosis is based on clinical examination and confirmed by ultrasonographic examination. The ultrasonographic appearance of the supraspinous ligament has been well described, but there are few studies that correlate ultrasonographic findings with clinical pain and/or pathology. This preliminary study aims to test the hypothesis that unridden horses (n = 13) have a significantly reduced frequency of occurrence of ultrasonographic changes of the SSL consistent with a diagnosis of desmitis when compared to ridden horses (n = 13) and those with clinical signs of back pain (n = 13). Results The supraspinous ligament of all horses was imaged between T(thoracic)6-T18 and ultrasonographic appearance. There was an average of 2.08 abnormal images per horse from the whole group. The average number of abnormalities in unridden horses was 4.92, in ridden horses 2.92 and in horses with clinical back pain 4.69. No lesions were found between T6 and T10 and 68% of lesions were found between T14 and T17. No significant difference (p < 0.05) was found between the three groups in the number or location of abnormal images. Conclusion The main conclusion was that every horse in this study (n = 39) had at least one site of SSL desmitis (range 2 to 11). It was clear that ultrasonographically diagnosed SSL desmitis cannot be considered as prima facie evidence of clinically significant disease and further evidence is required for a definitive diagnosis.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are