642 research outputs found

    DIRECT NUMERICAL SIMULATION OF FLUIDIZED BED WITH IMMERSED BOUNDARY METHOD

    Get PDF
    The applicability of the immersed boundary (IB) method, which is one of direct numerical simulations (DNS) for multiphase flow analyses, has been examined to simulate a fluidized bed. The volumetric-force type IB method developed by Kajishima et al. (2001) has been applied in the present work. While particle-fluid interaction force is calculated with the surface integral of fluid stress at the interface between particle and fluid in the standard IB method, the volume integral of interaction force is used in the volumetric-force type IB method. In order to validate the present simulation code, drag force and lift force firstly were calculated with IB method. Then calculated drag coefficients were compared with values estimated with Schiller-Nauman and Ergun equations, while calculated lift coefficients were compared with the previous simulated results. The difference of drag was within approximately 1% except in the range of low Reynolds number. Thus, the accuracy of the present simulation code was confirmed. Next, simulation of fluidized bed was carried out. Since DNS requires a large computer capacity, only 400 particles were used. The particle is 1.0mm in diameter and 2650kg/m3 in density. From the simulated results, concentrated upward stream lines from the bottom wall were observed in some regions. This inhomogeneous flow would be attributed to particulate structure

    Photodisintegration cross section of ⁴He in the giant dipole resonance energy region

    Full text link
    We have performed for the first time the simultaneous measurement of the two-body and three-body photodisintegration cross sections of ⁴He in the energy range from 21.8 to 29.8 MeV using monoenergetic pulsed photons and a 4π time projection chamber containing ⁴He gas as an active target in an event-by-event mode. The photon beam was produced via the Compton backscattering of laser photons with high-energy electrons. The ⁴He(γ,p)³H and ⁴He(γ,n)³He cross sections were found to increase monotonically with energy up to 29.8 MeV, in contrast to the result of a recent theoretical calculation based on the Lorentz integral transform method that predicted a pronounced peak at around 26–27 MeV. The energy dependence of the obtained ⁴He(γ,n)³He cross section up to 26.5 MeV is marginally consistent with a Faddeev-type calculation predicting a flat pattern of the excitation function. The cross section ratio of ⁴4He(γ,p)³H to ⁴He(γ,n)³He is found to be consistent with the expected value for charge symmetry of the strong interaction within the experimental uncertainty in the measured energy range. The present results for the total and two-body cross sections of the photodisintegration of ⁴He are compared to previous experimental data and recent theoretical calculations.Murata M., Kawabata T., Adachi S., et al. Photodisintegration cross section of ⁴He in the giant dipole resonance energy region. Physical Review C 107, 21 (2023); https://doi.org/10.1103/PhysRevC.107.064317

    Photo-disintegration cross section measurements on 186^{186}W, 187^{187}Re and 188^{188}Os: Implications for the Re-Os cosmochronology

    Full text link
    Cross sections of the 186^{186}W, 187^{187}Re, 188^{188}Os(γ,n\gamma,n) reactions were measured using quasi-monochromatic photon beams from laser Compton scattering (LCS) with average energies from 7.3 to 10.9 MeV. The results are compared with the predictions of Hauser-Feshbach statistical calculations using four different sets of input parameters. In addition, the inverse neutron capture cross sections were evaluated by constraining the model parameters, especially the E1E1 strength function, on the basis of the experimental data. The present experiment helps to further constrain the correction factor FσF_{\sigma} for the neutron capture on the 9.75 keV state in 187^{187}Os. Implications of FσF_{\sigma} to the Re-Os cosmochronology are discussed with a focus on the uncertainty in the estimate of the age of the Galaxy.Comment: 11 page

    Subaru FOCAS Spectroscopic Observations of High-Redshift Supernovae

    Full text link
    We present spectra of high-redshift supernovae (SNe) that were taken with the Subaru low resolution optical spectrograph, FOCAS. These SNe were found in SN surveys with Suprime-Cam on Subaru, the CFH12k camera on the Canada-France-Hawaii Telescope (CFHT), and the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). These SN surveys specifically targeted z>1 Type Ia supernovae (SNe Ia). From the spectra of 39 candidates, we obtain redshifts for 32 candidates and spectroscopically identify 7 active candidates as probable SNe Ia, including one at z=1.35, which is the most distant SN Ia to be spectroscopically confirmed with a ground-based telescope. An additional 4 candidates are identified as likely SNe Ia from the spectrophotometric properties of their host galaxies. Seven candidates are not SNe Ia, either being SNe of another type or active galactic nuclei. When SNe Ia are observed within a week of maximum light, we find that we can spectroscopically identify most of them up to z=1.1. Beyond this redshift, very few candidates were spectroscopically identified as SNe Ia. The current generation of super red-sensitive, fringe-free CCDs will push this redshift limit higher.Comment: 19 pages, 26 figures. PASJ in press. see http://www.supernova.lbl.gov/2009ClusterSurvey/ for additional information pertaining to the HST Cluster SN Surve

    s -process branching at W 185 revised

    Get PDF
    The neutron capture cross section of the unstable s-process branching nucleus 185W has been derived from experimental data of the inverse 186W(g,n)185W photodisintegration taken with monochromatic photon beams from laser Compton scattering. The result of sigma = 553 +- 60 mb at kT = 30 keV leads to a relatively high effective neutron density in the classical s-process of N_n = 4.7 \times 10^8 cm^-3. A realistic model for the s-process in thermally pulsing AGB stars overestimates the abundance of 186Os significantly because of the relatively small neutron capture cross section of 185W.Comment: 10 pages, 3 figure

    EML4–ALK fusion transcript is not found in gastrointestinal and breast cancers

    Get PDF
    Fusion genes have been identified as chromosomal rearrangements in certain cancers, such as leukaemia, lymphoma, and sarcoma. The EML4–ALK (EML4: echinoderm microtubule-associated-protein-like 4; ALK: anaplastic lymphoma kinase) fusion gene has been identified as an oncogene in non-small-cell lung cancer (NSCLC). This study examined the presence of this fusion transcript in gastrointestinal and breast cancers. We evaluated the expression of the EML4–ALK transcript in 104 lung cancer cases and in 645 gastrointestinal and breast cancer samples. Only one of the lung cancer samples tested positive for the EML4–ALK fusion transcript, whereas none were detected in 555 gastrointestinal and 90 breast cancer cases. Our data suggest that the EML4–ALK fusion transcript is not present in gastrointestinal or breast cancers and is specific to NSCLC

    Correlations between peripheral parasite load and common clinical and laboratory alterations in dogs with visceral leishmaniasis

    Get PDF
    Intensity of peripheral parasite infection has an important role in the transmission of Leishmania spp. from one host to another. As parasite load quantification is still an expensive procedure to be used routinely in epidemiological surveillance, the use of surrogate predictors may be an important asset in the identification of dogs with high transmitting ability. The present study examined whether common clinical and laboratory alterations can serve as predictors of peripheral parasitism in dogs naturally infected with Leishmania spp. Thirty-seven dogs were examined in order to establish correlations between parasite load (PL) in multiple peripheral tissues and common clinical and laboratory findings in canine visceral leishmaniasis (CVL). Quantitative polymerase chain reaction was employed to determine PL in conjunctival swabs, ear skin, peripheral blood and buffy coat. Additionally, a series of hematological, biochemical and oxidative stress markers were quantified. Correlations between net peripheral infection and severity of clinical alterations and variation in laboratory parameters were assessed through a new analytical approach, namely Compressed Parasite Load Data (CPLD), which uses dimension reduction techniques from multivariate statistics to summarize PL across tissues into a single variable. The analysis revealed that elevation in PL is positively correlated with severity of clinical sings commonly observed in CVL, such as skin lesions, ophthalmic alterations, onycogriphosis, popliteal lymphadenomegaly and low body mass. Furthermore, increase in PL was found to be followed by intensification of non-regenerative anemia, neutrophilia, eosinopenia, hepatic injury and oxidative imbalance. These results suggest that routinely used clinical and laboratory exams can be predictive of intensity of peripheral parasite infection, which has an important implication in the identification of dogs with high transmitting ability
    corecore