Time Reversal Mirror and Perfect Inverse Filter in a Microscopic Model for Sound Propagation

Time reversal of quantum dynamics can be achieved by a global change of the Hamiltonian sign (a hasty Loschmidt daemon), as in the Loschmidt Echo experiments in NMR, or by a local but persistent procedure (a stubborn daemon) as in the Time Reversal Mirror (TRM) used in ultrasound acoustics. While the first is limited by chaos and disorder, the last procedure seems to benefit from it. As a first step to quantify such stability we develop a procedure, the Perfect Inverse Filter (PIF), that accounts for memory effects, and we apply it to a system of coupled oscillators. In order to ensure a many-body dynamics numerically intrinsically reversible, we develop an algorithm, the pair partitioning, based on the Trotter strategy used for quantum dynamics. We analyze situations where the PIF gives substantial improvements over the TRM.Comment: Submitted to Physica

Critical boron-doping levels for generation of dislocations in synthetic diamond

Defects induced by boron doping in diamond layers were studied by transmission electron microscopy. The existence of a critical boron doping level above which defects are generated is reported. This level is found to be dependent on the CH4 /H2 molar ratios and on growth directions. The critical boron concentration lied in the 6.5–17.0 X 10 20 at/cm3 range in the direction and at 3.2 X 1021 at/cm 3 for the one. Strain related effects induced by the doping are shown not to be responsible. From the location of dislocations and their Burger vectors, a model is proposed, together with their generation mechanism.6 page

A multistage combined approach to promote diabetic wound healing in COVID-19 era

When diabetes mellitus is not properly controlled with drugs and a healthy lifestyle, it exposes patients with advanced peripheral arterial disease or critical limb ischaemia (CLI) to the most serious complications, in particular lower limb ulcers. Surgical or endovascular treatments represent the first line of intervention; in addition, the adequate management of ulcers can guarantee not only a faster wound healing but also the improvement of the patient's prognosis. To speed up this process, negative pressure wound therapy (NPWT), platelet-rich plasma (PRP), and other advanced moist wound dress- ing have been proposed. During Coronavirus disease 2019 (COVID-19) pan- demic, many patients with CLI and diabetes mellitus had difficult access to advanced treatments with a significant reduction in life expectancy. We report the cases of patients with non-healing ulcers and CLI treated with an empiric multistage approach after successful endovascular revascularisation; the post- operative course was eventful in all patients, and foot ulcers are currently in an advanced state of healing. The association between adequate revascularisation, systemic anti-inflammatory, and antibiotic therapy with the multistage advanced medications ensures healing of ulcers, limb salvage, and improvement of patient prognosis

Considerações sobre a estratigrafia do Grupo Açungui (Proterozóico Superior), Paraná, sul do Brasil

The stratigraphic order of the Açungui Group was significantly altered by thrust stacking of tectonic slices during basin closure. These slices presently show one or more regularly ordered internai lithological assemblages, which correspond to only a part of the original stratigraphic column. In Paraná, the Açungui Group is made up by the Capiru, Votuverava and Antinha Formations, each including three distinct lithologic assemblages, which are frequenüy limited by thrust faults. The Capiru Formation comprises the Juruqui, Rio Branco and Morro Grande assemblages; the Votuverava Formation comprises the Bromado, Coloninha and Saivá assemblages; and the Antinha Formation comprises the Tacaniça, Capivara and Vuturuvu assemblages. The spectrum of lithologic assemblages shows contrasting depositional environments, from very shallow carbonate platform to continental slope with turbidite deposits. Climatic conditions varied from hot and wet to glacial or subglacial.A atual estratigrafia do Grupo Açungui não é original, mas resulta do empilhamento de fatias tectônicas como conseqüência do cavalgamento que ocorreu durante o fechamento da bacia. Cada fatia contém um ou mais conjuntos iitológicos, com ordenação estratigráfica regular, e que representam partes preservadas da coluna estratigráfica original. O Grupo Açungui, do Proterozóico superior, compreende as formações Capiru, Votuverava e Antinha, cada uma com pelo menos três conjuntos litológicos distintos, na maioria das vezes separados uns dos outros por falhas de cavalgamento. A primeira compreende os conjuntos Juruqui, Rio Branco e Morro Grande, a segunda, os conjuntos Bromado, Coloninha e Saivá e o terceiro, os conjuntos Tacaniça, Capivara e Vuturuvu. Os conjuntos Iitológicos representam ambientes deposicionais os mais variados, desde plataforma com sedimentação carbonática, de águas bem rasas, até áreas de talude, com depósitos turbidíticos. O clima variou desde quente e úmido a glacial ou subglacial

Mapeamento de áreas suscetíveis a deslizamentos no município de Pato Branco, Paraná com a aplicação do modelo SHALSTAB

Este trabalho compara modelos matemáticos de estabilidade de encostas associados a técnicas de mapeamento temático em SIG. O objetivo principal foi avaliar a aplicação do modelo SHALSTAB no mapeamento de áreas suscetíveis à ocorrência de escorregamentos na região de Pato Branco, Paraná, buscando determinar a quantidade de chuva necessária para desencadear estes eventos extremos e comparar com resultados de trabalhos anteriores que determinaram os fatores de segurança das encostas dessa área. Os resultados obtidos demonstraram que ambas metodologias analisadas mostraram-se aptas como ferramenta para identificar zonas de susceptibilidade à ocorrência de escorregamento raso, uma vez que os deslizamentos ocorridos na cidade estão localizados em áreas consideradas instáveis pelos dois métodos.This paper compares mathematical models of slope stability associated with thematic mapping techniques in GIS. The main objective was to evaluate the application of SHALSTAB model in the susceptible mapping areas to the occurrence of landslides in Pato Branco, Paraná State, aiming to determine the needed amount of rain to trigger these extreme events and to compare, with previous studies results, what have determined the security factors of the slopes in this area. The results showed that both analyzed methodologies proved suitable as a tool for identifying susceptibility to the occurrence of slip shallow areas, once the slips occurred in the city are located in areas considered unstable by both methods

Deterministic analysis of slope stability in the Serra do Mar (Paraná, southern Brazil)

Abstract Number: GHZ06232

Biomedical Co-Cr-Mo Components Produced by Direct Metal Laser Sintering

Direct Metal Laser Sintering (DMLS) is an additive manufacturing technique based on a laser power source that sinters powdered materials using a 3D CAD model. The mechanical components produced by this procedure typically show higher residual porosity and poorer mechanical properties than those obtained by traditional manufacturing techniques. In this study, samples were produced by DMLS starting from a Co-Cr-Mo powder (in the \u3b3 phase) with a composition suitable for biomedical applications. Samples were submitted to hardness measurements and structural characterization. The samples showed a hardness value remarkably higher that those commonly obtained for the same cast or wrought alloys. In fact, the HRC value measured for the samples is 47 HRC, while the usual range for CAST Co-Cr-Mo is from 25 to 35 HRC. The samples microstructure was investigated by X-ray diffraction (XRD), electron microscopy (SEM and TEM) and energy dispersive microanalysis (EDX) in order to clarify the origin of this unexpected result. The laser treatment induced a melting of the metallic Co-Cr-Mo powder, generating a phase transformation from the \u3b3 (fcc) to the e (hcp) phase. The rapid cooling of the melted powder produced the formation of e (hcp) nano-lamellae inside the \u3b3 (fcc) phase. The nano-lamellae formed an intricate network responsible for the measured hardness increase. The results suggest possible innovative applications of the DMLS technique to the production of mechanical parts in the medical and dental fields, where a high degree of personalization is required