The variation of comonomers feeding profile to design the distribution of chains composition for the optimization of the mechanical properties in copolymer systems

Abstract

Context. Determining the parameters of massive stars is crucial to understand many processes in galaxies and the Universe, since these objects are important sources of ionization, chemical enrichment and momentum. 10m class telescopes enable us to perform detailed quantitative spectroscopic analyses of massive stars in other galaxies, sampling areas of different metallicity. Relating the stars to their environment is crucial to understand the physical processes ruling their formation and evolution. Aims. In preparation for the new instrumentation planned for the Gran Telescopio CANARIAS (GTC), our goal is to build a list of massive star candidates in the metal-poor irregular galaxy IC 1613. The catalogue must have very high astrometric accuracy, suitable for the current generation of multi-object spectrographs. A census of OB associations in this galaxy is also needed, to provide important additional information about the age and environment of the candidate OB stars. Methods. From observations taken with the Wide Field Camera (WFC) at the Isaac Newton Telescope (INT), we have built an astrometric and photometric catalogue of stars in IC 1613. Candidate blue massive stars are preselected by their colors. A friendsof-friends algorithm is developed to find their clustering in the galaxy. While a common physical origin for all the members of the associations cannot be ensured, this is a necessary first step to place candidate OB stars in a population context. Results. We have produced a deep catalogue of targets in IC 1613 that covers a large field of view. To achieve high astrometric accuracy, a new astrometric procedure was developed for the INT-WFC data. We also built a catalogue of OB associations in IC 1613 and found that they concentrate in the central regions, especially in the HII bubbles. The study of extinction confirms that it is patchy, with local values of color-excess above the foreground value. " ESO 2009.",,,,,,"10.1051/0004-6361/200911791",,,"http://hdl.handle.net/20.500.12104/45323","http://www.scopus.com/inward/record.url?eid=2-s2.0-68649120034&partnerID=40&md5=faa85fbdaaca529e8a0a8094382f3e39",,,,,,"3",,"Astronomy and Astrophysics",,"1015

1041",,"502",,"Scopus

WOS",,,,,,"Catalogs; Galaxies: individual: IC 1613 Astrometry; Galaxies: photometry; Galaxy: stellar content; Stars: early-type",,,,,,"The young stellar population of IC 1613 I. A new catalogue of OB associations",,"Article" "47092","123456789/35008",,"Rodríguez-Noriega, E., Instituto de Patología Infecciosa y Experimental Dr. Francisco Ruíz Sánchez, Universidad de Guadalajara, Jalisco, México.; Morfin-Otero, R., Instituto de Patología Infecciosa y Experimental Dr. Francisco Ruíz Sánchez, Universidad de Guadalajara, Jalisco, México.; Esparza-Ahumada, S., Instituto de Patología Infecciosa y Experimental Dr. Francisco Ruíz Sánchez, Universidad de Guadalajara, Jalisco, México.",,"Rodriguez-Noriega, E.

Morfin-Otero, R.

Esparza-Ahumada, S.",,"1993",,"The size of the antibiotic market in developing countries is double that seen in developed countries. There are some valid reasons for this difference, one of which is the higher frequency of diverse infections in the developing world. However, other factors are involved: for example, antibiotics are available without prescription, package insert information is poor, and there is no national antibiotic usage programme, all of which encourage inappropriate antibacterial use. When an antibiotic becomes widely prescribed by physicians, this is interpreted by the general public as meaning that the antibiotic is useful for all types of infections and the process of automedication begins. The newer quinolones, other new antibiotics, and indeed all antimicrobials should be available only by prescription. A package insert that includes all pertinent information should be provided, and each country should implement a comprehensive national antibiotic usage programme. Only through these measures will bacterial resistance be controlled and the effectiveness of each antibiotic class be maintained.",,,,,,,,,"http://hdl.handle.net/20.500.12104/45313","http://www.scopus.com/inward/record.url?eid=2-s2.0-0027179778&partnerID=40&md5=1220a0ad21fe9f9c6a44794ae861f2bc

http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med3&AN=7689450",,,,,,,,"Drugs",,"42

45",,"45 Suppl 3",,"Scopus

MEDLINE",,,,"Index Medicus;4-Quinolones;Anti-Infective Agents/tu [Therapeutic Use];Developing Countries;Drug Resistance, Microbial;Drug Utilization;Humans;Medicine;Mexico;Specialization",,,,,,,,"The use of quinolones in developing countries.",,"Review" "47099","123456789/35008",,"Arnez-Prado, A.H., Chemical Engineering Department, Universidad de Guadalajara, Blvd. Gral. Marcelino García Barragan No. 1451, Guadalajara Jalisco, 44430, Mexico; González-Ortiz, L.J., Chemistry Department, Universidad de Guadalajara, Blvd. Gral. Marcelino García Barragan No. 1451, Guadalajara Jalisco, 44430, Mexico; Aranda-García, F.J., Chemistry Department, Universidad de Guadalajara, Blvd. Gral. Marcelino García Barragan No. 1451, Guadalajara Jalisco, 44430, Mexico; Jasso-Gastinel, C.F., Chemical Engineering Department, Universidad de Guadalajara, Blvd. Gral. Marcelino García Barragan No. 1451, Guadalajara Jalisco, 44430, Mexico",,"Arnez-Prado, A.H.

Gonzalez-Ortiz, L.J.

Aranda-García, F.J.

Jasso-Gastinel, C.F.",,"2012",,"Semicontinuous seeded emulsion copolymerizations, using 5 different types of feeding profiles of comonomers (styrene/butyl acrylate, S/BA) were carried out, to vary in a gradual manner the composition of the copolymer chains formed throughout the reactions (gradient composition copolymer, GCC). For comparison, equivalent core-shell type polymeric materials were synthesized in two stages (T-S). In all reactions, the S/BA global mass ratio was: 70/30. To estimate the weight composition distribution (WCD) of the copolymer chains, the cumulative styrene content in the polymer mass was followed throughout the reaction ( 1H-NMR). Average molecular weights were determined using SEC. The differences in mechanical performance were established, carrying out a mechanodynamic (DMA), and mechanostatic characterization (stress-strain at several temperatures and, Izod testing). The area under the loss modulus curve (LA) was correlated with Izod impact strength, showing the damping superiority of the GCCs over the T-S material. At all tested temperatures (between 25 and 70 °C), the GCC materials exhibited yielding and plastic deformation, while the T-S material presented brittle fracture in that temperature interval. The WCDs were used to elucidate the differences in mechanical behaviour among GCC materials. The feeding profile variation in combination with the WCD analysis represents a novel methodology to produce tailor made copolymers. " ARKAT-USA, Inc.