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On a length-biased life distribution based on the sinh-normal model
Antonio Sanhueza,Víctor Leiva,Esteban Flores 한국통계학회 2009 Journal of the Korean Statistical Society Vol.38 No.4
In this article, we characterize a new life distribution based on the sinh-normal model. Specifically, we find the density, the distribution function, and the moments of the new model. In addition, we carry out a brief graphical analysis of its density. Furthermore, we derive some properties and transformations related to the new distribution. Moreover, we conduct a study of its hazard rate. Finally, we present an example that illustrates the obtained results and a computational implementation of these results.
J. P. Sanhueza,D. Rojas,J. García,M. F. Melendrez,E. Toledo,F. M. Castro Cerda,C. Montalba,A. F. Jaramillo 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9
In this study, three martensitic creep-resistant steels with 100, 90, and 70 ppm of boron were investigated. The experimentaldata obtained from isothermal aging and creep test at 650 °C were compared with the results of simulation conductedusing TC-PRISMA software. Tungsten was found to be the rate-controlling element in the coarsening of (Cr, Fe, W)23C6carbides; however, this result differed in terms of boron-containing steel. Several studies indicate that the low solubility ofboron in ferrite promotes boron enrichment in (Cr, Fe, W)23C6 carbide, thereby reducing its coarsening rate. However, thismechanism is not universally agreed upon. In the present study, a comparison between experimental and theoretical resultsrevealed that in boron-containing steels, the coarsening of (Cr, Fe, W)23C6 carbide is controlled probably by boron volumediffusion or by trans-interface diffusion.
Contreras, Yanett,Sanhueza, Patricio,Jackson, James M.,Guzmá,n, André,s E.,Longmore, Steven,Garay, Guido,Zhang, Qizhou,Nguyê,̃,n-Lu’o’, Quang,Tatematsu, Ken’ichi,Nakamura, Fumita American Astronomical Society 2018 The Astrophysical journal Vol.861 No.1
<P>Using Galactic Plane surveys, we have selected a massive (1200M circle dot), cold (14 K) 3.6-70 mu m dark IRDC, G331.372-00.116. This infrared dark cloud (IRDC) has the potential to form high-mass stars, and given the absence of current star formation signatures, it seems to represent the earliest stages of high-mass star formation. We have mapped the whole IRDC with the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.1 and 1.3 mm in dust continuum and line emission. The dust continuum reveals 22 cores distributed across the IRDC. In this work, we analyze the physical properties of the most massive core, ALMA1, which has no molecular outflows detected in the CO (2-1), SiO (5-4), and H2CO (3-2) lines. This core is relatively massive (M = 17.6M circle dot), subvirialized (virial parameter alpha(vir) = M-vir/M = 0.14), and is barely affected by turbulence (transonic Mach number of 1.2). Using the HCO+ (3-2) line, we find the first detection of infall signatures in a relatively massive, prestellar core (ALMA1) with the potential to form a high-mass star. We estimate an infall speed of 1.54 km s(-1) and a high accretion rate of 1.96. x. 10(-3) M circle dot yr(-1). ALMA1 is rapidly collapsing, out of virial equilibrium, which is more consistent with competitive accretion scenarios rather than the turbulent core accretion model. On the other hand, ALMA1 has a mass similar to 6 times larger than the clumps Jeans mass, as it is in an intermediate mass regime (M-J = 2.7 < M less than or similar to 30 M circle dot), contrary to what both the competitive accretion and turbulent core accretion theories predict.</P>
Zhang, Chuan-Peng,Liu, Tie,Yuan, Jinghua,Sanhueza, Patricio,Traficante, Alessio,Li, Guang-Xing,Li, Di,Tatematsu, Ken’ichi,Wang, Ke,Lee, Chang Won,Samal, Manash R.,Eden, David,Marston, Anthony,Liu, Xia American Astronomical Society 2018 The Astrophysical journal Supplement series Vol.236 No.2
<P>In order to understand the initial conditions and early evolution of star formation in a wide range of Galactic environments, we carried out an investigation of 64 Planck Galactic cold clumps (PGCCs) in the second quadrant of the Milky Way. Using the (CO)-C-13 and (CO)-O-18 J = 1-0 lines and 850 mu m continuum observations, we investigated cloud fragmentation and evolution associated with star formation. We extracted 468 clumps and 117 cores from the (CO)-C-13 line and 850 mu m continuum maps, respectively. We made use of the Bayesian distance calculator and derived the distances of all 64 PGCCs. We found that in general, the mass-size plane follows a relation of m similar to r(1.67). At a given scale, the masses of our objects are around 1/10 of that of typical Galactic massive star-forming regions. Analysis of the clump and core masses, virial parameters, densities, and mass-size relation suggests that the PGCCs in our sample have a low core formation efficiency (similar to 3.0%), and most PGCCs are likely low-mass star-forming candidates. Statistical study indicates that the 850 mu m cores are more turbulent, more optically thick, and denser than the (CO)-C-13 clumps for star formation candidates, suggesting that the 850 mu m cores are likely more appropriate future star formation candidates than the (CO)-C-13 clumps.</P>
Delva, Jorge,Andrade, Fernando H.,Sanhueza, Guillermo,Han, Yoonsun SAGE Publications 2015 International social work Vol.58 No.2
<P>To inform social work practice with adolescents who may consume alcohol, we examined if alcohol use among Chilean adolescents varied as a function of their mothers’ and their own religiosity and spirituality. Data were from 787 Chilean adolescents and their mothers. Adolescent spirituality was a protective factor against more deleterious alcohol use. Parental monitoring and alcohol using opportunities mediated the associations. The practice of religious behaviors by themselves without meaningful faith were not associated with alcohol use among adolescents. Implications for social work practice are discussed.</P>
Astrochemical Properties of Planck Cold Clumps
Tatematsu, Ken’ichi,Liu, Tie,Ohashi, Satoshi,Sanhueza, Patricio,Nguyê,̃,n Lu’o’, Quang,Hirota, Tomoya,Liu, Sheng-Yuan,Hirano, Naomi,Choi, Minho,Kang, Miju,A.Thompson, Mark,Fuller, Gary,Wu, Y Published by the University of Chicago Press for t 2017 The Astrophysical journal Supplement series Vol.228 No.2
<P>We observed 13 Planck cold clumps with the James Clerk Maxwell Telescope/SCUBA-2 and with the Nobeyama 45 m radio telescope. The N2H+ distribution obtained with the Nobeyama telescope is quite similar to SCUBA-2 dust distribution. The 82 GHz HC3N, 82 GHz CCS, and 94 GHz CCS emission are often distributed differently with respect to the N2H+ emission. The CCS emission, which is known to be abundant in starless molecular cloud cores, is often very clumpy in the observed targets. We made deep single-pointing observations in DNC, (HNC)-C-13, N2D+, and cyclic-C3H2 toward nine clumps. The detection rate of N2D+ is 50%. Furthermore, we observed the NH3 emission toward 15 Planck cold clumps to estimate the kinetic temperature, and confirmed that most targets are cold (less than or similar to 20 K). In two of the starless clumps we observed, the CCS emission is distributed as it surrounds the N2H+ core (chemically evolved gas), which resembles the case of L1544, a prestellar core showing collapse. In addition, we detected both DNC and N2D+. These two clumps are most likely on the verge of star formation. We introduce the chemical evolution factor (CEF) for starless cores to describe the chemical evolutionary stage, and analyze the observed Planck cold clumps.</P>
THE SCALING RELATIONS AND STAR FORMATION LAWS OF MINI-STARBURST COMPLEXES
Nguyê,̃,n-Lu’o, Quang,Nguyê,̃,n, Hans V. V.,Motte, Fredé,rique,Schneider, Nicola,Fujii, Michiko,Louvet, Fabien,Hill, Tracey,Sanhueza, Patricio,Chibueze, James O.,Didelon, P American Astronomical Society 2016 The Astrophysical journal Vol.833 No.1
<P>The scaling relations and star formation laws for molecular cloud complexes (MCCs) in the Milky Way are investigated. MCCs are mostly large (R> 50 pc), massive (similar to 106 M circle dot) gravitationally unbound cloud structures. We compare their masses M-gas, mass surface densities Sigma(Mgas), radii R, velocity dispersions sigma, star formation rates (SFRs), and SFR densities Sigma(SFR) with those of structures ranging from cores, clumps, and giant molecular clouds, to MCCs, and galaxies, spanning eight orders of magnitudes in size and 13 orders of magnitudes in mass. This results in the following universal relations: sigma similar to R-0.5, M-gas similar to R-2, Sigma(SFR) similar to Sigma(1.5)(Mgas) , SFR similar to M-gas(0.9) , and SFR similar to sigma(2.7) Variations in the slopes and coefficients of these relations are found at individual scales, signifying different physics acting at different scales. Additionally, there are breaks at the MCC scale in the sigma-R relation and between starburst and normal star-forming objects in the SFR-M-gas and Sigma(SFR)-Sigma(Mgas) gas relations. Therefore, we propose to use the Schmidt-Kennicutt diagram to distinguish starburst from normal star-forming structures by applying a SMgas threshold of similar to 100M circle dot pc (2) and a Sigma(SFR) threshold of 1M circle dot yr (1) kpc (2). Mini-starburst complexes are gravitationally unbound MCCs that have enhanced Sigma(SFR) (> 1M circle dot yr(-1) kpc(-2)), probably caused by dynamic events such as radiation pressure, colliding flows, or spiral arm gravitational instability. Because of dynamical evolution, gravitational boundedness does not play a significant role in regulating the star formation activity of MCCs, especially the mini-starburst complexes, which leads to the dynamical formation of massive stars and clusters. We emphasize the importance of understanding mini-starbursts in investigating the physics of starburst galaxies.</P>
The Properties of Planck Galactic Cold Clumps in the L1495 Dark Cloud
Tang, Mengyao,Liu, Tie,Qin, Sheng-Li,Kim, Kee-Tae,Wu, Yuefang,Tatematsu, Ken’ichi,Yuan, Jinghua,Wang, Ke,Parsons, Harriet,Koch, Patrick M.,Sanhueza, Patricio,Ward-Thompson, D.,Tó,th, L. Viktor,S American Astronomical Society 2018 The Astrophysical journal Vol.856 No.2