6,295 research outputs found
The seroepidemiology of pertussis in Australia during an epidemic period.
No full textStudying the epidemiology of pertussis and impact of differing vaccine schedules is difficult because of differing methods of case ascertainment. The advent of internationally standardized serological diagnosis for recent infection has allowed comparison of age-specific pertussis infection among European countries and was applied in Australia at the time of a major national epidemic. In 1997 and 1998, a nationally representative serum bank using residual sera from diagnostic laboratories was established. Measurement of pertussis toxin (PT) IgG level was conducted by a reference laboratory using an enzyme-linked immunosorbent assay standardized for a number of European countries. A titre of 125 EU/ml was interpreted as indicative of recent pertussis infection. The serological data were correlated with age, gender, region and disease epidemiology in Australia. The highest prevalence of recent pertussis infection was in the 5–9 years age group, and the lowest in 1–4 and 25–64 years age groups. In the 5–14 years age group, 29·7% (5–9 years) and 14·6% (10–14 years) of the sample had serological evidence of recent infection, correlating with the pattern of epidemic notifications. The 15- to 24-year-olds had similar high titres but the same notification rate as 25- to 44-year-olds, suggesting ascertainment bias may result in under-notification in the former age group. The prevalence of high titres observed was up to 20-fold higher than some European countries during a similar time period. Although vaccination has reduced the transmission of pertussis in the youngest and most vulnerable age group, pertussis is still endemic in Australia, particularly in older children and the elderly. The Australian vaccination schedule has been changed in an attempt to address this problem, by spacing doses more widely, with the fifth dose at 15–17 years of age. Seroepidemiology for pertussis offers the potential to compare patterns of pertussis between countries and examine the impact of vaccine schedule changes independent of notification and diagnostic bia
Cr(VI) and Cr(III)-Based Conversion Coatings on Zinc
No full textWith the aims of understanding the protective mechanism of chromate conversion coatings and developing alternatives to chromate treatments, the physical natures and corrosion properties of Cr(VI) and Cr(III) treated zinc have been investigated in this work. The Cr(VI) treatments were carried out in dichromate and sulfuric acid solution with different dipping times. The Cr(III) treatments were carried out in two commercial solutions (A and B). The thickness of the coatings was measured using ellipsometry. The morphologies and the compositions of the treated zinc have been studied by means of SEM, AFM, AES, FTIR and XPS. The drying temperature influence on the corrosion performance of the Cr(VI)âtreated zinc has been investigated. The Volta potential in treated and untreated areas has been measured using scanning Kelvin probe (SKP) and SKPFM. The corrosion behavior of the Cr(VI) and Cr(III) treated zinc has been investigated using polarization, electrochemical impedance measurements (EIS), and salt spray tests. Both Cr(VI) and Cr(III) species were detected by XPS in the outermost layer of the Cr(VI) coatings, while no Cr(VI) species was found in the Cr(III) coatings. AES depth profile results show that chromium oxides are the main components in the Cr(VI) coatings. Zinc oxide is mainly located at the chromium oxides / zinc interface. The Cr(III) coating is a mixture of chromium oxides and zinc oxide. Both the Cr(VI) and the Cr(III) treatments can supply corrosion protection to zinc. The corrosion resistance of the Cr(III)-B coating is greater than that of the Cr(III)-A coating. However, the inhibition of the corrosion of zinc by Cr(VI) coating is more effective than by the Cr(III) coatings. The inhibition of the corrosion of zinc by the Cr(VI) and the Cr(III) treatments is discussed, and future research topics are suggested.Mechanical, Maritime and Materials Engineerin
“I’ll be back”: Australia’s experience of flu in 2022
No full textRaina MacIntyre and colleagues look at what we can learn from Australia’s 2022 flu seaso
Site occupation in the Cr-Ru and Cr-Os ? phases
No full textThe site occupation in the Cr-Ru and Cr-Os ? phases is computed as a function of temperature. Generally, in ? phases the larger atoms occupy the sites with larger coordinations numbers, as can be explained on the basis of atomic-size and electronic structure. However, for Cr2Ru and Cr2Os the atomic-size argument predicts that Ru and Os occupy the sites with larger coordination numbers, whereas the reasoning based on the approximate degeneracies of electronic levels predicts that Cr occupies those sites. By comparing these predictions with the theoretically computed and the experimentally measured site occupations, the atomic-size and electronic arguments can be judged on their predictive merits.Materials Science and EngineeringMechanical, Maritime and Materials Engineerin
Nonlinear influence of excess Mn on the magnetoelastic transition in (Mn,Cr)<sub>2</sub>Sb
No full textThe influence of excess Mn on the magnetoelastic ferromagnetic-to-antiferromagnetic transition Tt in the magnetocaloric compound (Mn,Cr)2Sb has been studied. With increasing excess Mn the magnetoelastic transition temperature for (Mn,Cr)2Sb initially increases and then decreases. This trend is accompanied by a strong reduction of the (Mn,Cr)Sb secondary phase. With increasing excess Mn a higher Cr content was found in the (Mn,Cr)Sb secondary phase in comparison to the matrix phase. This competition for Cr leads to a nonlinear dependence of Tt with increasing excess Mn at a fixed nominal Cr content. However, we observed that Tt depends linear on the c/a ratio for a wide range of temperatures from 170 to 350 K. A compositional diagram of the c/a ratio was constructed to assist the selection of (Mn,Cr)2Sb alloys with a desired transition temperature.RST/Fundamental Aspects of Materials and Energ
Ultradifferentiable CR Manifolds
No full textIn this article, the notion of ultradifferentiable CR manifold is introduced and an ultradifferentiable regularity result for finitely nondegenerate CR mappings is proven. Here, ultradifferentiable means with respect to Denjoy–Carleman classes defined by weight sequences. Furthermore, the regularity of infinitesimal CR automorphisms on ultradifferentiable abstract CR manifolds is investigated.© The Author(s) 201
elliegiulietti/V-Cr-Ti-for-Fusion-Reactors: Vanadium_Alloys (V-Cr-Ti)_for_Fusion_Reactors_AM_Study_Release_v1.0
No full text<h2>Vanadium Alloys (V-Cr-Ti) for Fusion Reactors AM Study</h2>
<p>This repository contains the research and experimental data related to the study on vanadium alloys (specifically V-Cr-Ti alloys, V44 and V1515) for fusion reactors using additive manufacturing (AM) techniques.</p>
<h3>Overview</h3>
<p>Vanadium alloys are potential materials for nuclear fusion reactors due to their structural durability and irradiation resistance. This study focuses on investigating the viability of V-Cr-Ti alloys for AM procedures, aiming to understand crack behaviour and optimise laser parameters for better melt track formation.</p>
<h3>Key Findings</h3>
<ul>
<li>Experimental investigations involved varying laser power and speed on V-Cr-Ti alloys (V44 and V1515) to observe crack behaviour across melt tracks on a laser powder bed fusion (LPBF) machine.</li>
<li>Main types of cracks associated with AM melt tracks were identified, including liquation cracks (LC), solidification cracks (SC), and solid-state cracks (SSC).</li>
<li>Qualitative analysis involved visually determining crack types using optical microscopes and scanning electron microscopy (SEM), while quantitative analysis measured crack density using ImageJ software.</li>
<li>Results indicate that high laser power and low laser speeds result in increased cracking, while low laser power with a mid-range of laser speeds result in less cracking and a more optimal melt track.</li>
<li>An operating window between 60 and 150 W laser power and 850 to 1500 mm/s has been identified, with further studies required for confirmation and comparison to powder processing.</li>
</ul>
<h3>Future Directions</h3>
<ul>
<li>Future studies should focus on comparing data with similar alloys, refining laser parameters, and exploring microstructural properties for deeper insights into crack formation mechanisms.</li>
<li>Sharing of experimental data to facilitate accessibility and reusability for the scientific community.</li>
</ul>
<h3>Dissertation Details</h3>
<p>Dissertation submitted to the University of Sheffield in partial fulfilment of the requirements for the degree of Master of Engineering.
Dissertation title: Vanadium Alloys for Fusion Reactors: Determining their Viability for Additive Manufacturing Procedures.
Author: Ellie Giulietti
Supervisor: Dr Russell Goodall
May 2024</p>
Kinetics of internal oxidation of Fe-Mn-Cr steel alloys
No full textSelective oxidation behaviour of Fe-Mn-Cr steel alloys annealed at 950°C in Ar plus 5 vol.% H2 atmosphere under different annealing time and dew points was studied. The Fe-Mn-Cr steel alloys are externally oxidized when annealing at dew point of -45 °C, while internally oxidized at dew points of -10 and 10 °C. The internal oxides formed in the Fe-Mn-Cr steel alloys are (Mn, Fe)O and (Cr, Mn, Fe)3O4. The kinetics of internal oxidation of Fe-Mn-Cr alloys at 950 °C is diffusion controlled and follows parabolic growth rate law. The measured kinetics of internal oxidation of Fe-Mn-Cr alloys and the concentration depth profiles of internal oxides are in good agreement with simulation results. Adding Cr to the Fe-Mn steel alloys decreases the kinetics of internal oxidation. The growth rate of internal oxidation zone can be predicted by a modified Wagner’s internal oxidation model. The external oxides formed during annealing of Fe-Mn-Cr steel alloys cannot be reduced by H2. However, an oxide-free steel surface can be obtained by first forming and then reducing a Wüstite scale.Materials Science and Engineerin
Enhanced performance of hexavalent chromium reducing cathodes in the presence of Shewanella oneidensis MR-1 and lactate
No full textBiocathodes for the reduction of the highly toxic hexavalent chromium (Cr(VI)) were investigated using Shewanella oneidensis MR-1 (MR-1) as a biocatalyst and performance was assessed in terms of current production and Cr(VI) reduction. Potentiostatically controlled experiments (?500 mV vs Ag/AgCl) showed that a mediatorless MR-1 biocathode started up under aerated conditions in the presence of lactate, received 5.5 and 1.7 times more electrons for Cr(VI) reduction over a 4 h operating period than controls without lactate and with lactate but without MR-1, respectively. Cr(VI) reduction was also enhanced, with a decrease in concentration over the 4 h operating period of 9 mg/L Cr(VI), compared to only 1 and 3 mg/L, respectively, in the controls. Riboflavin, an electron shuttle mediator naturally produced by MR-1, was also found to have a positive impact in potentiostatically controlled cathodes. Additionally, a microbial fuel cell (MFC) with MR-1 and lactate present in both anode and cathode produced a maximum current density of 32.5 mA/m2 (1000 ? external load) after receiving a 10 mg/L Cr(VI) addition in the cathode, and cathodic efficiency increased steadily over an 8 day operation period with successive Cr(VI) additions. In conclusion, effective and continuous Cr(VI) reduction with associated current production were achieved when MR-1 and lactate were both present in the biocathodes
. 11-12 Año 6 (2017) enero-agosto. CR. Conservación y restauración
No full text- Editorial por Manuel Alejandro González Gutiérrez y Magdalena Rojas Vences. -Proyecto de atención del acervo documental de Ixcamilpa de Guerrero por Patricia de la Garza Cabrera, Marie Vander Meeren, Laura Olivia Ibarra Carmona, Nora A. Pérez Castellanos, Carlos Orejel Delgadillo, Silvia Yocelin Pérez Ramírez, Débora Y. Ontiveros Ramírez, Denisse Ochoa Gutiérrez, Hugo Arriaga González y Gerardo Gutiérrez. - Haciendo frente a los embates medioambientales: conservación integral del sitio rupestre Cuevas Pintas,Baja California Sur por Sandra Cruz Flores, Alejandra Bourillón Moreno, Anacaren Morales Ortiz, Rodrigo Ruiz Herrera y María Fernanda López-Armenta. - Estrategia para la accesibilidad e inclusión de las personas con discapacidad a zonas arqueológicas “El pasado es de todos” por Daniela Tovar Ortiz y Luis Antonio Huitrón Santoyo. - Atención a grupos sociales. Sistematización de actividades por Manuel González Gutiérrez y Denisse Ochoa Gutiérrez. - Tañendo campanas: trabajando en equipo. Intervención de las campanas robadas en la capilla de Nuestra Señora de la Concepción, Escobedo, Nuevo León por Gabriela Peñuelas Guerrero, Carlos I. Cañete Ibáñez, Claudia Sánchez Gándara, Jannen Contreras Vargas e Ingrid K. Jiménez Cosme. - La apropiación del patrimonio cultural de El Ocote. Una aportación etnográfica para la sostenibilidad por Hugo Arriaga González. - Churubusco. 50 años en la memoria. Una muestra conmemorativa de la conservación en el INAH por Mónica Badillo Leal, Gabriela Gómez Llorente y Mariana Pascual Cáceres. - Los órganos y su conservación en la CNCPC por Norma Cristina Peña Peláez, Sandra María Álvarez Jacinto, José Luis Acevedo Guzmán y Fanny Magaña Nieto. - Conservación de cestería en espiral proveniente de la Cueva de la Candelaria, Torreón, Coahuila: criterios, tratamientos y líneas de investigación por Gloria Martha Sánchez Valenzuela, Miriam Elizabeth Castro Rodríguez y Adriana Reyes García. - Evaluación de recubrimientos de protección para metales. Caso de estudio: Imagen de México, relieve escultórico del Museo Nacional de Antropología. Primera etapa por Aline Moreno Núñez, Arturo A. Egea Salas, Gilda E. Salgado Manzanares, Mauricio B. Jiménez Ramírez, Armando Arciniega Corona y Nora A. Pérez Castellanos. - Patrimonio arqueológico digital. Uso de las tecnologías de la información y la comunicación para la divulgación del patrimonio arqueológico por Eduardo Andrés Escalante Carrillo y Luis Antonio Huitrón Santoyo. - El laboratorio de documentación y análisis tridimensional de la CNCPC. Resultados a un año de operación María Fernanda López-Armenta, Gilberto García Quintana y Celedonio Rodríguez Vidal. - La conservación-restauración de los bienes culturales en el Museo Regional de Querétaro: retos y perspectivas por María del Rosario Bravo Aguilar Conocer y reconocer a los actores sociales en la conservación de los bienes patrimoniales por Mitzi Vania García Toribio y Fanny Magaña Nieto. - Foro Anual de Trabajo. Una historia sin historia en el archivo de la CNCPC por Débora Y. Ontiveros Ramírez. - Expediente de incidentes en el tiempo. El Ehécatl-Quetzalcóatl de Coyoacán y cómo su caso puede ser usado para difundir la conservación en museos por Roberto Velasco Alonso. - Conservación en la vida cotidiana por María Bertha Peña Tenorio. - La Mediateca del INAH por Thalía E. Velasco Castelán. - Finaliza CNCPC la recuperación de sillares simulados originales en la bóveda del templo franciscano de Huaquechula, Puebla por Oscar Adrián Gutiérrez Vargas. - San Francisco de Asís en Huejotzingo, Puebla María Eugenia Rivera Pérez. - Investiga INAH factores de deterioro en la pirámide de la Serpiente Emplumada por Oscar Adrián Gutiérrez Vargas. - Lo que querías saber y no te atrevías a preguntar sobre el INAH en El Ocote por Oscar Adrián Gutiérrez Vargas. - Para saber más de El Caballito por Oscar Adrián Gutiérrez Vargas
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