Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Geological conditioning aspects for piezocone test interpretation for stratigraphical identification in geotechnical and geo-environmental site investigation

As campanhas de investigação geotécnica e geoambiental do subsolo utilizam diversos tipos de sondagem e ensaios com objetivo de mapear a distribuição espacial das unidades e definir os parâmetros de projeto específicos para cada tipo de intervenção. A etapa de identificação da distribuição e da constituição dos materiais é comum a grande parte dos projetos e normalmente é conduzida através de sondagens em campo que produzem uma perfilagem pontual e vertical do terreno. Os estudos realizados durante esta pesquisa tiveram como principal objetivo avaliar a influência da história geológica na execução e na interpretação dos ensaios de piezocone para identificação estratigráfica. Os ensaios de piezocone sísmico foram realizados com objetivo de identificar a interface entre solos lateríticos e os não-laterítico. Os ensaios de piezocone de resistividade foram realizados principalmente para avaliação de intrusões de cunhas de águas salinas em aqüíferos sedimentares rasos. Desta forma, foram selecionadas nove áreas localizadas em regiões com diferentes condições geológicas, representativas do território brasileiro. Abrangem sedimentos quaternários das planícies litorâneas, sedimentos cenozóicos de bacias tafrogênicas e solos tropicais desenvolvidos a partir de rochas sedimentares e ígneas da Bacia do Paraná. Os locais foram selecionados em função da disponibilidade de informações adequadas às análises pretendidas. Nos sedimentos os resultados dos ensaios de piezocone foram eficazes na caracterização estratigráfica, classificação dos sedimentos e estimativa de parâmetros de projeto a partir de correlações. Nestes sedimentos, a experiência internacional, adquirida principalmente em sedimentos da América do Norte e Europa, pôde ser utilizada. Os ensaios com piezocone de resistividade foram eficazes em identificar intrusões salinas no aqüífero, contribuindo também para identificação da estratigrafia do perfil. Nestes sedimentos foram observadas relações consistentes entre a história de formação do perfil e as propriedades geotécnicas estimadas a partir da interpretação dos ensaios de piezocone. Já, nos solos tropicais, os processos de intemperísmo produzem transformações no perfil que dificultam a definição da estratigrafia, a classificação dos solos e a estimativa de parâmetros com base em correlações. Em solos tropicais, os ensaios com piezocone de resistividade foram ineficientes na identificação da profundidade do nível dágua e na definição da sequência estratigráfica, provavelmente devido à presença de óxidos de ferro e nível de água profundo. Já, os ensaios de piezocone sísmico foram eficazes para diferenciar os solos de comportamento laterítico dos de comportamento não-laterítico através da relação Go/qc. Conclui-se que o entendimento da história geológica é fundamental na interpretação dos ensaios de piezocone, principalmente na etapa de integração entre ensaios pontuais, para identificação da geometria e variabilidade dos solos. A quantidade de processos ou de variáveis independentes que contribuem para a formação do perfil de solo normalmente aumenta a variabilidade. Neste sentido, ensaios combinados, como o piezocone sísmico, onde vários parâmetros podem ser obtidos em um mesmo ponto, contribuem para minimizar os efeitos da variabilidade na estimativa de parâmetros de projetoIn situ tests for geotechnical and geo-environmental site investigation embraces a variety of soundings and tests to map and define stratigraphic logging and specific design parameters for each kind of job. Stratigraphic logging and soil classification are a common stage to all investigation programs and frequently they are performed throughout logging tests which results in local vertical information. The main objective of this research is to evaluate the influence of geological history in the interpretation of piezocone tests for stratigraphic logging. Seismic piezocone tests were carried out to try to identify difference response between lateritic and non lateritic soils. Resistivity piezocone tests were carried out to evaluate salt-water intrusion within a shallow sedimentary aquifer. In this sense, nine sites with different geologic conditions, representing extensive area from Brazil, were selected and investigated. They include quaternary sediment sequences on the brazilian coast, tafrogenic sedimentary sequences and tropical soils originated from weathering of Paraná basin sedimentary and igneous rocks. Piezocone tests were effective for stratigraphic logging, sediment classification as well as to estimate geotechnical design parameters based on correlations for sedimentary sediments. For these type of soils, the international experience developed for sedimentary soils from North America and Europe can be used. Resistivity piezocone tests were effectively useful to identify salt-water intrusion within a sedimentary aquifer and contributed to refine soil stratigraphy. Consistent relations between geologic history and geotechnical properties were established based on piezocone test results. In the other hand, the weathering process produces profile transformations in the tropical soils and imposes limitations to stratigraphy definition, soil classification and to estimate geotechnical soil parameters based on these correlations. For tropical soils, the resistivity piezocone test was not efficient to identify the groundwater level and to refine stratigraphic logging, probably due to the presence of iron oxides and deep groundwater. The seismic piezocone tests were effective to separate lateritic and non-lateritic soils throughout the relation between maximum shear modulus and poit resistance (Go/qc). It is concluded that the geological information is fundamental for the interpretation of piezocone results, especially to integrate several logging test data, to identify spatial distribution and variability of soil layers. In this sense, combined tests, such as the seismic piezocone, where more than one parameter can be measured at the same location, contribute to minimize variability effects in the estimation of geotechnical soil parameter

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 O Mapeamento Geotécnico é uma ferramenta indispensável, básica na elaboração de planejamento da ocupação, que procura caracterizar as propriedades do terreno de interesse para Engenharia e Planejamento e prever as interações entre os processos do meio físico, o homem e suas obras.  As sucessivas agressões ao meio ambiente tornam necessária a elaboração de planejamentos abrangentes, que tenham uma base geomorfológica segundo o conceito de Avaliação dos Terrenos (\"Land Evaluation\").  O presente estudo abrange a Quadrícula de Mogi-Guaçu, situada na porção centro-leste do Estado de São Paulo e com aproximadamente 715 km², sendo elaborado embasando-se nas propostas metodológicas de Zuquettte (1987) e PUCE (item 2.2.3), com modificações.  A apresentação dos resultados é feita de maneira descritiva, por meio de mapas e tabelas, incluindo, além dos mapas tradicionalmente apresentados, um mapa de sistemas de relevo, um mapa de limitações à ocupação e uma tabela com propriedades geotécnicas de interesse para a engenharia. The Geotechnical Mapping is an important tool in planning the occupation of lands. It deals with properties that are interesting to Engineering and Planning, and try to foresee the relations between the natural processes, the man and his works.  The sucessive agressions to the land has required the elaboration of a wide planning with a geomorphological base, using the concept of Land Evaluation.  The present study include the Mogi-Guaçu area, in the central-east portion of São Paulo State, with about 715 km². The work follows the Zuquette (1987) and PUCE methodologies, with modifications.  The results are presented in maps and tables, including a relief system map, a map of limitations to occupation, and a table with geotechnical properties of interest to engineering

The use of piezocone tests for high-resolution stratigraphy of Quaternary sediment sequences in the Brazilian coast

Correlations between mapping units of costal sedimentary basin and interpretation of piezocone test results are presented and discussed based on examples from Caravelas strandplain, (State of Bahia), Paranaguá (State of Paraná) and Guarujá bays (State of São Paulo), Brazil. Recognizing that the sedimentary environment was mainly controlled by sea level fluctuations led to the interpretation of transgressive and regressive sedimentary sequences, which is in a good agreement with the sea level fluctuation curves currently accepted for these regions. The interpretation of piezocone test results shows that the sedimentary sequences of Caravelas and Guarujá sites are similar and they have a good correlation to the sea level fluctuation curve accepted for Salvador region, State of Bahia. On the other hand, the piezocone test results from Paranaguá site indicate a different sedimentary sequence from the previous ones, relating to the sea level fluctuation curve accepted for Paranaguá region. The results show the high applicability of piezocone testing for stratigraphical logging and suggest that it is possible to integrate it with other current techniques used for paleo-environmental studies in Brazil, in accordance with recent approaches used in international research on the subject

Investigação de Intrusão de Água Salgada em Aqüífero Superficial a Partir de Medidas de Resistividade Elétrica

A site investigation program was carried out to detect salt-water intrusions in a shallow sedimentary aquifer based on electrical resistivity measurements. The site is located close to Paranaguá harbor, in the Paraná State, Brasil. At this site, high chloride concentration contaminated shallow water wells used to supply water for local industries. The site investigation program included a fieldwork, dipole-dipole electrical profiling, resistivity piezocone tests, physical-chemical analysis of sampled water and interpretation of borehole logs. The resistivity piezocone tests provided two simultaneous information; the soil stratigraphy at a very detailed level and a quasi-continuous resistivity profile. Both information adequately complemented dipole-dipole electrical profiling test data. The integration of all test data allowed identifying the contaminated areas as well as guided the location of new water wells to be installed in this area