Early Science Result from the Japanese Virtual Observatory: AGN and Galaxy Clustering at z = 0.3 to 3.0

We present the result of projected cross correlation analysis of AGNs and galaxies at redshifts from 0.3 to 3.0. The Japanese Virtual Observatory (JVO) was used to obtain the Subaru Suprime-Cam images and UKIDSS catalog data around AGNs. We investigated 1,809 AGNs, which is about ten times larger a sample than that used in previous studies on AGN-galaxy clustering at redshifts larger than 0.6. 90% of the AGN samples are optically-selected AGN from the SDSS and 2dF catalogs. The galaxy samples at low redshift includes many redder objects from UKIDSS survey, while at higher redshift they are mainly blue galaxies from Suprime-Cam. We found significant excess of galaxies around the AGNs at redshifts from 0.3 to 1.8. For the low redshift samples ($z<0.9$), we obtained correlation length of $r_{0} =$5--6 $h^{-1}$Mpc ($\gamma = 1.8$), which indicates that the AGNs at this redshift range reside in a similar environment around typical local galaxies. We also found that AGNs at higher redshift ranges reside in a denser environment than lower redshift AGNs; For $z=1.3 \sim 1.8$ AGNs, the cross correlation length was measured as 11$^{+6}_{-3}$ $h^{-1}$Mpc ($\gamma=1.8$). Considering that our galaxies sample is based on optical observations with Suprime-Cam at the redshift range, it is expected that blue star-forming galaxies comprise the majority of objects that are observed to be clustered around the AGNs. It is successfully demonstrated that the use of the archive through the Virtual Observatory system can provide a powerful tool for investigating the small scale environment of the intermediate redshift AGNs.Comment: accepted to PASJ, 36 pages, 21 figures, this is an accepted versio

Investigation on the petrophysical changes of a coquina core subjected to carbonate water injection

Orientadores: Osvair Vidal Trevisan, Erika Tomie Koroishi BliniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de GeociênciasResumo: Os métodos de recuperação avançada de petróleo que utilizam o CO2 como fluido de injeção acompanham alguns desafios associados às reações químicas entre a rocha, o fluido de injeção e petróleo. Estes processos frequentemente induzem mudanças substanciais nas propriedades petrofísicas (porosidade e permeabilidade) das rochas do reservatório. Um melhor entendimento destes fenômenos pode, por exemplo, diminuir potencialmente o risco de se cometer erros no desenvolvimento de um reservatório de hidrocarbonetos e também levar a uma melhor política ambiental de estocagem de CO2 no subsolo. Esta dissertação tem como objetivo investigar as mudanças nas propriedades petrofísicas de amostras de coquina de afloramento sujeitas à injeção de água carbonatada em diferentes vazões de injeção. Estas diferentes vazões foram escolhidas de modo a varrer uma maior gama de regimes de dissolução. Este trabalho consistiu em uma análise laboratorial das mudanças nas propriedades petrofísicas em coquinas devido à injeção de água carbonatada em condições de alta pressão (2.000 psi) e temperatura ambiente (18oC). As rochas utilizadas foram coquinas de afloramento análogas ao pré-sal brasileiro, e as condições de vazão variam desde 0,025 ml/min até 2 ml/min sendo que para o primeiro experimento as vazões empregadas foram: 0,1; 0,5 e 2 ml/min. Já para o segundo experimento, as vazões foram mais baixas: 0,025; 0,075; 0,1 e 2 ml/min. As definições operacionais do segundo experimento levaram em conta os desafios e aprendizados do primeiro. As mudanças visaram atingir outro regime de dissolução e uma maior quantidade e qualidade dos dados obtidos. Para a avaliação das propriedades petrofísicas, um porta-testemunho especial com seis tomadas de pressão foi utilizado acoplado a transdutores de pressão, assim como a análise dos efluentes e tomografias computadorizadas de raios-X ao longo dos experimentos. Devido ao pioneirismo e aos desafios associados à montagem experimental, diversas metodologias foram desenvolvidas em parceria com o Laboratório de Métodos Miscíveis e de Recuperação (LMMR). Foram observados aumentos de permeabilidade muito acentuados no primeiro experimento, já no segundo houve um aumento seguido por uma posterior redução brusca. Estes efeitos foram atribuídos a dissolução (no caso dos aumentos), e à precipitação (para o caso das reduções). Utilizando os resultados obtidos das propriedades petrofísicas foi possível obter uma estimativa dos valores de Péclet e Damköhler, números adimensionais que definem o regime de dissolução, que concordaram com os regimes observados através das imagens de tomografia. No primeiro experimento houve um aumento de 2,4% na porosidade e 11,8D na permeabilidade. A permeabilidade aumentou na totalidade da amostra, porém este aumento não foi uniformemente distribuído. A região próxima a face de injeção sofreu maiores aumentos, o que é esperado visto que o fluido injeção penetra na amostra quimicamente desbalanceado e conforme avança ao longo do comprimento da amostra torna-se mais estável quimicamente com a rocha. Porém, um comportamento similar foi observado na região de produção da amostra, o que indica uma grande heterogeneidade petrofísica da amostra. Foi possível observar a formação de um wormhole dominante conectando as faces de entrada e saída do testemunho por um canal preferencial com baixa resistência ao fluxo. No segundo experimento observou-se grande heterogeneidade petrofísica como no primeiro. A porosidade aumentou em 0,5% e a permeabilidade aumentou em 2,79 D. Houve a formação de um wormhole possivelmente ramificado, mas sem a formação de um canal preferencial ao fluxoAbstract: The enhanced oil recovery methods which utilize the CO2 as an injection fluid are accompanied by some challenges associated with the chemical reactions between the rock, the injection fluid and the oil. These processes frequently create substantial changes in the petrophysical properties (porosity and permeability) of the reservoir rock. A better understanding of these phenomena may, for example, potentially reduce the risk of making mistakes in the development of a hydrocarbon reservoir and also to lead to a better environmental policy of CO2 stockage underground. This dissertation has as objective to analyze the process of dissolution and the changes associated to it. Some phenomenon like the creation of preferential paths known as wormholes occur in carbonate rocks and influences in an intense way the reservoir permeability. This work consisted of a laboratory analysis the petrophysical properties changes of coquinas due to the injection of carbonate water in high pressure (2,000 psi) and room temperature (18oC) conditions. The rocks used in this work are outcrop coquinas analogous to the Brazilian pre-salt, and the flow conditions vary from 0.025 ml/min to 2 ml/min in the two experiments. The first experiment used high flow rates of 0.1; 0.5 and 2 ml/min, and the second experiment used low flow rates of 0.025; 0.075; 0.1 and 2 ml/min. To evaluate the petrophysical properties, a special coreholder with six pressure taps was coupled to pressure transducers, effluent analysis and X-ray computerized tomography were used through the experiment. Due to the pioneering and the challenges associated with the experimental setup, various methodologies were developed in association with the Laboratory of Miscible and Recuperation Methods (LMMR). Steep permeability increases were observed in the first experiment, while in the second there was an increase followed by a great decrease. These effects were attributed to the dissolution (when the permeability increased), and to the precipitation (in the cases of reduction). Using the experimental results of the petrophysical properties it was possible to estimate the values of the Péclet and Damköhler dimensionless numbers, which define the dissolution regime, and they were in agreement with the behavior observed in the tomography images. There was an increase of 2.4% in the porosity and 11.8 D in the permeability for the first experiment. The permeability increased in the whole sample, but this increase was not evenly distributed. The region close to the injection suffered the greatest increases, which is expected since the injection fluid enters the sample chemically unbalanced and as it advances through the sample length it becomes more chemically stable with the rock. However, a similar behavior was observed in the production region of the sample, which indicates a high degree of petrophysical heterogeneity of the sample. It was possible to observe the formation of a dominant wormhole connecting both inlet and outlet faces of the core and creating a preferential channel with low resistance to the flow. In the second experiment a great degree of petrophysical heterogeneity was observed as in the first experiment. Porosity increased by 0.5% and permeability by 2.79 D. There was the formation of a wormhole possibly ramified, but without the creation of a preferential channel to the flowMestradoReservatórios e GestãoMestre em Ciências e Engenharia de Petróleo134491/2016-5CNP

D6 Family Symmetry and Cold Dark Matter at LHC

We consider a non-supersymmetric extension of the standard model with a family symmetry based on D6 Z2 Z2, where one of Z2's is exactly conserved. This Z2 forbids the tree-level neutrino masses and simultaneously ensures the stability of cold dark matter candidates. From the assumption that cold dark matter is fermionic we can single out the D6 singlet right-handed neutrino as the best cold dark mater candidate. We find that an inert charged Higgs with a mass between 300 and 750 GeV decays mostly into an electron (or a positron) with a large missing energy, where the missing energy is carried away by the cold dark matter candidate. This will be a clean signal at LHC.Comment: 20 pages, 7 figure

Exit or Continue? An Empirical Analysis of SMEs in Ota-ku and Higashiosaka, Japan (Japanese)

This study investigates what types of firms and managers wish to exit or to continue in a market by focusing on two areas renowned for the high concentrations of manufacturing small and medium enterprises (SMEs) in Japan: Ota-ku in Tokyo Metropolitan and Higashiosaka in Osaka Prefecture. The results clearly indicate that high profitability and the possession of a specific technology are associated with a wish to continue in a market, while low profitability and the absence of a specific technology are associated with a wish to exit. The results also show that sole proprietor operations and small-scale businesses are associated with a desire to exit. Furthermore, it is found that firms in Ota-ku have a tendency toward a desire to exit than those in Higashiosaka.