Measurement of residual stresses in a dissimilar metal welded pipe

Dissimilar metal welds (DMW) are used in light water reactor power plants to join ferritic and austenitic steel piping components. High residual stresses remaining in this type of welded joint can significantly increase its susceptibility to stress corrosion cracking (SCC) under water reactor chemistry conditions. This degradation mechanism has compromised the integrity of many nuclear power plants throughout the world over the past 10 years. The Open University (OU) is undertaking a programme of research aimed at improving the reliability of residual stress measurements in DMWs using neutron diffraction. AREVA, the French nuclear power plant constructor, has developed an improved narrow gap DMW weld using a nickel-based corrosion resistant filler (alloy-52) to eliminate the risk of SCC in next generation nuclear plant. Through-wall neutron measurements have been carried out on a full-size DMW mock-up (352 mm OD, 40 mm thick) using the ENGIN-X instrument at the ISIS Facility in the UK. The results have shown that the largest tensile stress components in the welded component lie in the hoop direction, and have values of around 250 MPa and 225 MPa in the austenitic and alloy-52 materials respectively. These measured stresses were in reasonable agreement with those obtained from deep-hole drilling and numerical simulations. A notable finding in the experimental work was a wide scatter in the measured unstressed lattice parameters within a range equivalent to micro-strains of ≈ 430, 400 and 600 for austenitic stainless steel, ferritic steel and alloy-52 respectively. This scatter was reduced by two orders of magnitude through making additional measurements whilst slowly rotating the stress-free reference cubes. The OU is undertaking systematic studies to identify the origins of the observed measurement scatter in order to improve the reliability of measurements

Efects of temperature, air velocity and thickness over degradation of ascorbic acid during convective drying of mango and papaya

[SPA] El proceso de secado de frutas degrada la calidad tanto física (textura, color) como nutricional. El uso de indicadores de calidad, permite inferir acerca del estado nutricional de un alimento. El ácido ascórbico (c6h8o6), es un indicador de calidad ya que al ser uno de los nutrientes más sensibles al tratamiento térmico aplicado en frutas, su retención asegura que otros componentes permanezcan sin alterarse durante el procesamiento. Por lo tanto, el objetivo de este trabajo fue evaluar la degradación de ácido ascórbico durante el secado convectivo de rebanadas de mango y papaya en diferentes condiciones de operación. Se realizaron cinéticas de ácido ascórbico durante el secado a 40, 50, 60 y 70 ºC, a dos velocidades de aire (1,5 y 2,5 m/s), y dos espesores de rebanadas. Los resultados mostraron que la degradación de ácido ascórbico durante el secado sigue una conducta de primer orden. Con el total de los resultados se construyó un modelo de predicción de la constante de velocidad de degradación de ácido ascórbico como función de la temperatura y humedad del producto. El modelo demostró un efecto significante de la temperatura y humedad del producto sobre la constante de degradación. A menor humedad menor constante. Esto era esperado pues al disminuir la humedad disminuye la movilidad de las moléculas involucradas en la degradación. El modelo muestra que el efecto de la velocidad y espesor del producto son consecuencia de la evolución de temperatura y humedad. El modelo obtenido se puede aplicar en ecuaciones diferenciales del proceso de secado para encontrar las condiciones que minimicen la degradación del producto. [ENG] Fruits drying process usually produces a quality degradation both physical (texture, color) as nutritional. The use of quality indicators allows the estimation of the food nutritional state. Ascorbic acid (C6H8O6) may be considered as a quality indicator due its thermal sensitivity during fruits process, and therefore if it is retained indicates that another compounds present in foods can be not affected during process. Therefore, the aim of this work was to evaluate the ascorbic acid degradation during convective drying of mango and papaya at different operation conditions. Drying kinetics at 40, 50, 60 and 70º C, air velocities of 1.5 and 2.5 m/s, and product thickness of 1.0 and 1.5 cm were evaluated. The result showed that ascorbic acid degradation during drying follow a first order reaction. A prediction model for ascorbic acid degradation velocity constant as function of temperature and product moisture was build with the whole of experimental results. The model showed a significant effect of temperature and moisture over constant. Lower moisture indicates lower constant value. This was as expected because at lower moistures the molecular movement is constrained. The model shows that the effect of air velocity and product thickness have effect trough the temperature and moisture evolution. This model can be applied jointly with drying differential equations for predicting the conditions that minimize product degradation.Los autores agradecen al Consejo Nacional de Ciencia y Tecnología (CONACyT) de México por el soporte financiero del proyecto a través del convenio G35128-B.

Tau Protein Phosphorylated at Threonine-231 Is Expressed Abundantly in the Cerebellum in Prion Encephalopathies

ACKNOWLEDGMENTS: The authors want to express their gratitude to the following: Dr. P. Davies † (Albert Einstein College of Medicine, Bronx, NY, USA) and Lester I. Binder † (North Western, Chicago, IL, USA) for the generous gift of mAbs TG-3 and Alz-50, and Tau-1, Tau-5 and Tau-7, respectively; Tec. Amparo Viramontes Pintos for the handling of the brain tissue; support in the confocal microscopy unit of CIIDIR Durango, Instituto Politécnico Nacional; Union Medica University Clinic, Dominican Republic, for their support and collaboration in the development of this research project. We also want to express our gratitude to the Mexican families who have donated the brain of their loved ones affected with Alzheimer's disease and made our research possible. This work is dedicated to the memory of Professor Dr. José Raúl Mena López †. †Deceased. This work was supported by Fondo Nacional de Ciencia y Tecnologia, FONDOCyT, from the Ministry of Higher Education, Science and Technology, Dominican Republic (2015-3A2-127 to MP-H) and (2018-2019-2A3-208 to JL-M and MP-H).Peer reviewedPublisher PD

FCC testing at bench scale: New units, new processes, new feeds

As the FCC process has evolved over decades, several laboratory scale equipment have appeared to maintain a proper assessment of catalysts activity. Several laboratory equipments are available for simulating the FCC process, from the well known fixed bed, MicroActivity Test to newer, fluid bed or transported bed units. As well, a number of units have been created to simulate other parts of the process such as regenerator or stripper, The increased pressure for treating non-conventional feeds, from reprocessing gasoline to extra-heavy feeds or oils produced from biomass containing large amounts of heteroatoms, increase the needs to have a laboratory test which is as close as possible to the process so that data extraction from the laboratory test are simplified, thus less prone to errors or misunderstanding.Financial support by MICINN (Consolider-Ingenio 2010 MULTICAT) and MINECO (Project MAT2011-29020-0O2-02 and Subprogram for excellence Severo Ochoa, SEV 2012 0267) is gratefully acknowledged.Corma Canós, A.; Sauvanaud, LL. (2013). FCC testing at bench scale: New units, new processes, new feeds. Catalysis Today. 218-219:107-114. doi:10.1016/j.cattod.2013.03.038S107114218-21

Modelling the Microstructure and Mechanical Properties of Austempered Ductile Irons

Supporting materials for this thesis (computer programs) may be found on the website of the Materials Algorithms Project (MAP): http://www.msm.cam.ac.uk/map/mapmain.htm

Growth Morphologies and Primary Solidification Modes in a Dissimilar Weld between a Low-Alloy Steel and an Austenitic Stainless Steel

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Diálogo del saber campesino y la investigación científica: árboles nativos dendroenergéticos en la Reserva de la biosfera Sierra de Huautla, Morelos, México

The farming communities of the Sierra de Huautla, keep tradition in using firewood, which is strong pressure on the native deciduous trees. Through participatory dialogue with housewives and loggers and their local knowledge, 6 tree species were selected with value fuelwood in order to design agroforestry technologies that promote the use and the preservation. The species are: tlahuitol [Lysiloma divaricatum (Jacq.) Willd.], tepehuaje [Lysiloma acapulcense (Kunth) Benth.], palo Brasil (Haematoxylum brasiletto H.Karst.), palo dulce [Eysenhardtia polystachya (Ortega) Sarg.], tecolhuixtle (Mimosa benthamii J.F.Macbr.) and cubata blanca [Acacia pennatula (Schltdl. & Cham.) Benth.]. The contents of dry matter, moisture, organic matter, ash, as well as the heat of combustion and wood density rates, indicators of the quality of the wood, were measured for these species. Tecolhuixtle is the most diminished species by its highly desirable characteristics as firewood; currently, cubata blanca presents intense extraction, although the best species of wood for housewives and loggers are tlahuitol and tepehuaje