Residual stresses

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Relationship between residual stresses and mechanical behavior in ceramic composites

Relationship between residual stresses and mechanical behavior in ceramic composites

The calculated residual stresses in the alumina matrix by using the modified Eshelby model proposed by Taya [47] were very similar to those obtained by neutron diffraction measurements in this work, especially in the A-40YTZP composites. Such a good agreement was also observed for the residual stresses in the zirconia phase in the A-5YTZP composites. As the Y-TZP content increased to 40 vol. %, the tensile residual stress in the zirconia phase obtained from neutron diffraction measurements was slightly lower than the model predictions. According to recent work by C. Exare et al. [231], the attrition on alumina and zirconia slurries by high energy milling will influence the stability of the different zirconia phases and generate compressive residual stresses. Although in the present work, ball milling was used, the possibility that compressive residual stresses might be generated in zirconia should not be completely ruled out, especially when the volume fraction of zirconia is increased. This, in turn, might help to explain the differences observed between the residual stresses measured in zirconia by neutron diffraction and the model predictions.

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Evaluation of Residual Stresses Induced by Face Milling Using a Method of Micro-indents

Evaluation of Residual Stresses Induced by Face Milling Using a Method of Micro-indents

Abstract: The aim of this study is to determine and evaluate residual stresses induced by face milling in different zones, which are associated with asymmetries in orientation of cutting edge. In this study, a micro-indent method is used to determine these stresses, which were induced in samples of AA 7075-T6 aluminum alloy. The residual displacements were measured, with high accuracy, using a universal measuring machine. This study includes a thorough data analysis using Mohr's circles, which enabled to assess the stress states in all in-plane directions. The results obtained in samples subjected to different combinations of process parameters showed the introduction of compressive normal components for all directions of each zone evaluated. From the high sensitivity of the micro- indent method used, it was possible to detect smaller differences generated between the levels reaching the stress components in the cutting zones evaluated. Furthermore, these differences were similar for all evaluated directions when the highest feed rate was selected. This significant fact, finally, would reveal equivalent differences between asymmetrical zones, regarding the combination of local plastic deformation and heat reaching the milled surface, for all in-plane directions.

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Determination and Analysis of Residual Stresses Induced by High Speed Milling Using a Micro-indent Method

Determination and Analysis of Residual Stresses Induced by High Speed Milling Using a Micro-indent Method

These samples were milled at high speed using a numerically controlled vertical milling machine (Clever CMM-100). The tool, a face mill of 63 mm in diameter, includes five inserts (Palbit SEHT 1204 AFFN-AL SM10) of tungsten carbide. The values of cutting speed and depth of cut were V = 1000 m/min and d = 1.5 mm, respectively. Furthermore, the feed rate was varied from f = 0.1 mm/rev to f = 0.2 mm/rev in order to evaluate the behavior of the residual stresses in the cutting zones. Figure 3a shows a superior view of the relative position of the specimen regarding the cutting tool. This figure also shows two regions in the machined surface called climb and conventional cutting zones (Trent, 1991).

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Analysis of Residual Stresses in High Speed Milled Aluminum Alloys

Analysis of Residual Stresses in High Speed Milled Aluminum Alloys

However, residual stresses are introduced, inevitably, during the HSM of a mechanical component (Brinksmeier et al., 1982; Rao and Shin, 2001; Yao et al., 2012). This type of stresses can cause adverse effects on both the geometry and the life in service of different machined components. Due to this, the residual stresses must be studied exhaustively in the HSM regime. These stresses are caused by the plastic deformation generated by the interaction between the cutting tool and the material and also, by the heat conducted from the primary deformation zone to the surface generated (M’Saoubi et al., 2008; Abrão et al., 2011). It is important to note that these stresses are a

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Improved cold-drawn eutectoid steel wires based on residual stress measurement and simulation: Part 2. optimization of mechanical properties

Improved cold-drawn eutectoid steel wires based on residual stress measurement and simulation: Part 2. optimization of mechanical properties

In Figure 7 ferrite and cementite stresses are depicted together with the macrostress profile in an as-drawn eutectoid wire described in the first part of this paper [3,4]. Residual macrostresses are computed by the stress experimentally measured in every phase, weighted with their relative percentage in volume (rule of mixtures, in this case 90% ferrite and 10% cementite). This is a figure of significant interest (to the authors´ knowledge, the first time in which a whole profile of residual stresses has been obtained for both phases). From the macroscopic point of view, this profile shows tensile surface stresses with all the previously mentioned shortcomings. However, from the microscopic point of view, this is a very attractive profile. We should not forget that eutectoid steel could be considered as a composite material, a laminate material of alternating ferrite (matrix-soft phase) and cementite (reinforcing-hard phase) lamellae. In Figure 7 it is shown that the soft phase will be subjected to a previous compressive state, like a prestressing treatment inside the steel wire, which would be beneficial for the performance of the wire.

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Residual stress measurements of alumina-zirconia ceramics by time-of-flight neutron diffraction

Residual stress measurements of alumina-zirconia ceramics by time-of-flight neutron diffraction

Alumina-zirconia ceramics have received considerable attention in both engineering and academic fields due to their improved mechanical properties when compared with pure alumina ceramics [1-4]. It has been proposed that the residual stresses due to thermal and elastic mismatches between alumina and zirconia could contribute to toughening and enhance the structural performance of these ceramic composites [5, 6].

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Efecto residual de la aplicación de fertilizantes de nueva generación sobre la producción, composición y diversidad de pastos herbáceos en una dehesa toledana

Efecto residual de la aplicación de fertilizantes de nueva generación sobre la producción, composición y diversidad de pastos herbáceos en una dehesa toledana

Herbaceous pastures improvement is generally associated to phosphorous (P) fertilization. The objective of this practice is to increase dry matter yield and protein content through legume proportion rise. The main limiting factor for P fertilization effectiveness is water availability. There is also a residual effect after P fertilizer application or even a delayed effect in humid years after dry years with P fertilization. We analyze in this paper the delayed effect of traditional and new P fertilizers in dehesa herbaceous pastures in terms of yield, richness and botanical composition. The experiment was conducted in the CIA Dehesón del Encinar (Oropesa, Toledo) during 2013, monitoring three treatments: control, 36 UF of P 2 O 5 on NPK or

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Enfermedad mínima residual como predictor de recaída en leucemia linfoblástica aguda Instituto Nacional de Enfermedades Neoplásicas 2014 2016

Enfermedad mínima residual como predictor de recaída en leucemia linfoblástica aguda Instituto Nacional de Enfermedades Neoplásicas 2014 2016

Para determinar la enfermedad mínima residual (EMR) es por medio del método de citometria de flujo que sirve para discriminar las células fisiológicas normales, inmunofenotipo o reordenamiento, inmunoglobulinas de leucemia, y genes de Células T, además de otro método como transcripsiones de genes de fusión por reacción de cadena polimerasa cuantitativa en tiempo real (PCR), el PCR puede detectar hasta un 95% de EMR en los pacientes con leucemia linfoblástica aguda (LLA). Siendo alrededor del 30% al 40% de los pacientes con LLA precursoras de células B, y del 10% al 20% de los pacientes con LLA de células T, tienen aberacciones cromosomicas especificas que se pueden usar para detección de enfermedad mínima residual.

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Asma bronquial  Estado del arte

Asma bronquial Estado del arte

producido diariamente en la vía aérea es 355 ml y su función es facilitar el movimiento ciliar para que sea un efectivo mecanismo de transporte. El aclaramiento del moco se ve dismi- nuido normalmente durante el sueño. La crisis asmática se caracteriza por una obstrucción reversible al flujo aéreo, ocasionada por broncocons- tricción e inflamación de la pared de la vía aérea, inducida o no por estí- mulos inmunes. Esto se traduce en disminución de la capacidad vital forzada (CVF) y FEV1 como del pico máximo de flujo espiratorio (PEFR). Requieren una espiración activa por la gran resistencia al flujo aéreo espiratorio, con aumento del trabajo respiratorio y de la energía empleada en la respiración. Cuando la resis- tencia al flujo espiratorio se hace muy importante, se empieza a retener aire en el pulmón con aumento de los vo- lúmenes residuales. Los volúmenes pulmonares aumentados son el volu- men residual, la capacidad residual funcional y la capacidad pulmonar total durante las exacerbaciones de crisis asmática; se cree que se debe a la disminución de la elasticidad del pulmón y a que el aire está atrapado más allá de la obstrucción. La que siempre está disminuida es la capa- cidad vital 9 (Figura 1).

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Determinación del abatimiento del cloro en función al coeficiente de reacción en pared de tubería, en las redes de distribución de agua potable de la localidad de San Miguel de Monterrey

Determinación del abatimiento del cloro en función al coeficiente de reacción en pared de tubería, en las redes de distribución de agua potable de la localidad de San Miguel de Monterrey

El desarrollo de la tesis permitirá la determinación y análisis del decaimiento del cloro residual libre en la red de distribución de agua potable y con ello se podrá examinar el comportamiento del desinfectante en la red, haciendo posible definir estrategias para garantizar que la población de la localidad de San Miguel de Monterrey (distrito de Independencia, provincia de Huaraz, Ancash) consuma agua segura, contribuyendo así a la mejora de su calidad de vida. Para evidenciar el impacto social en la localidad de San Miguel de Monterrey, al inicio de la ejecución de la tesis se hará un diagnostico basal del siguiente indicador: casos de enfermedades gastrointestinales (se elige este indicador, por ser el principal y más representativo asociado a enfermedades de origen hídrico), ello se hará con ayuda del puesto de Salud de la localidad, y al final de la ejecución de la tesis se analizará cual fue la mejora de tal indicador.

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Diseño de un sistema de tratamiento de aguas residuales en la Planta de Lácteos “San Jacinto”, ubicada en el cantón Penipe, provincia de Chimborazo

Diseño de un sistema de tratamiento de aguas residuales en la Planta de Lácteos “San Jacinto”, ubicada en el cantón Penipe, provincia de Chimborazo

Se diseñó un sistema de tratamiento de aguas residuales para la Planta Láctea “San Jacinto”, que se encuentra ubicado en la Provincia de Chimborazo en el Cantón Penipe, la misma que requiere se cumpla con la norma ambiental vigente establecida en la Tabla 8 “Límites de descarga al sistema de alcantarillado público”, Libro VI Anexo 1, Normativa de Calidad Ambiental Recurso Agua del TULSMA, publicado en el registro oficial N°387. El agua residual no cumple con los parámetros establecidos dentro de la norma, se realizó la medición del caudal, posteriormente se la analizó permitiendo identificar los siguientes parámetros fuera de los límites permisibles según la normativa antes mencionada dando como resultado Aceites y Grasas, Fosforo Total, Solidos Totales, Demanda Bioquímica de Oxigeno y Demanda Química de Oxigeno con los valores de 289 mg/L, 54,48 mg/L, 11217 mg/L, 3581 mg/L, 6881 mg/L respectivamente. Una vez obtenido las variables operacionales se procedió a dimensionar los equipos para disminuir los contaminantes medidos, se definió el diseño el cual consta de lo siguiente un sistema de rejillas con un número de barras igual a 8 dispuestas en un canal que conducirá el agua a la trampa de grasa y aceite que va a tener un largo de 1.8 m, para luego llegar a un tanque imhoff de 2,59 m de

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Producción de Gladiolo (Gladiolus gandavensis) con lodo residual tratado en la ciudad de Puno

Producción de Gladiolo (Gladiolus gandavensis) con lodo residual tratado en la ciudad de Puno

The research work "PRODUCTION OF GLADIOL (GLADIOLUS GANDAVENSIS) WITH RESIDUAL SLUDGE TREATED IN THE CITY OF PUNO" was developed during two phases: the first one in the greenhouse of the "José Antonio Encinas" Technological Institute of Salcedo, Puno - Peru where Performed the bokashi-treated residual sludge composting, the second phase was carried out in the same institution but, in the open field with the management of Gladiolus cultivation during the 2013- 2014 agricultural season in the department, province and district of Puno An altitude 3824 msnm, 8243590 South Latitude and 393954 West Longitude. In the period from August 1, 2013 to March 30, 2014. The specific objectives were: a) to compare Gladiolus production with the incorporation of treated residual sludge, b) to determine the best dose of treated residual sludge applied for production Of Gladiolus, c) to estimate the economic profitability of Gladiolus culture with the application of treated residual sludge. For the data analysis aspect, the Block to Random (DBCA) design was used with a factorial arrangement of 1x 4x4 (1 variety of culture) (3 levels of treated residual sludge type Bokashi plus one control) (3 doses of Effective Microorganisms, Plus one control) 16 treatments and 4 replicates, making a total of 64 experimental units, the comparison of treatments was done by the Turkey test. As a conclusion, a) in cork production, treatment 16 (Gladiolus Duran variety + 60 mL of Activated Effective Microorganisms (EMa) per 1 liter of water + 25% treated residual sludge) obtained the highest number of corms , 75) on average. In the production of cormillos, treatment 16 (Gladiolus Duran + 60 mL Ema x 1 Liter of water + 25% treated residual sludge) obtained the largest number of corms with (26,50) on average, these exceed the control. In flower production, treatment 16 (Gladiolus Duran variety + 60 mL Ema x 1 Liter of water + 25% treated residual sludge), obtained the highest number of flowers with (23,04) on average and the control with (13,71) on average, b) As for the best treatment dose 16 (Gladiolus Duran + 60 mL Ema x 1 Liter of water + 25% treated residual sludge), c) On the profitability treatment 13 (Gladiolus variety Duran + 60 mL of Ema x 1 Liter of water + 100% untreated residual sludge), is the one that obtained the highest profitability with 578.69% having a profit of S/. 341074.10 and with a total cost of S /. 58939.23; Followed by treatment 1 (Gladiolus Duran + 0 mL of EMa + 100% untreated residual sludge), had a total cost of S / .58896.75, with yield of 489.71% with a gain of S / .588423.25.

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Propuesta de una tecnología para el tratamiento de residuales líquidos de la Tenería “Patricio Lumumba”

Propuesta de una tecnología para el tratamiento de residuales líquidos de la Tenería “Patricio Lumumba”

Las empresas de tenería de cuero emplean reactivos químicos muy agresivos durante el proceso de curtiembre. En el presente trabajo se exponen los resultados de la caracterización en el laboratorio de muestras de residuales líquidos vertidos en los procesos de pelambre, curtido y teñido de la tenería “Patricio Lumumba” en Caibarién por la elevada carga contaminante que presentan, evidenciado por la alta DQO, contenido de cromo trivalente y compuestos de carácter orgánicos e inorgánicos portadores de color respectivamente. Se logró la reducción de estos contaminantes a los niveles admisibles por los estándares ambientales a través de alternativas consistentes en la oxidación de sulfuros, remoción del cromo trivalente por precipitación química así como la decoloración con hipoclorito de sodio, tratamiento aplicado a cada una de los procesos objeto de estudio. Se proponen las tecnologías para cada residual y su escalado a nivel piloto cuya inversión se recupera en 4 años para la planta de tratamiento del residual del curtido, 4,5 años para la del residual del pelambre y 11 años para la del residual de teñido

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Effect of repeated scratches on the stresses behavior in a coated system

Effect of repeated scratches on the stresses behavior in a coated system

scratch on the coating, which suggests a possible failure (cracking) of the coating inside the groove, as well as, on the side of the contact with the indenter. This suggests, unlike the results of Holberg [15], that the first crack that appears is not of angular pattern but a crack of traction inside the groove, followed by lateral cracks possibly due to the accumulation of material in the part front and side of the contact with the indenter. Likewise, the results of stresses reached (S 11 , S 33 ) in subsequent scratch cycles on the same groove suggest the increase in the appearance

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Investigations on thermal stresses of a graded Ti(C,N) coating deposited on WC Co hardmetal

Investigations on thermal stresses of a graded Ti(C,N) coating deposited on WC Co hardmetal

Abstract. We investigated the stress behaviour of Ti(C,N) coatings deposited on WC-Co substrates during an individual thermal cycle. The stress analyses were performed in-situ by energy dispersive X-ray diffraction using a white synchrotron beam. The stresses were determined using the sin 2 ψ method combined with scattering vector measurements at the strain-free ψ-tilt, in order to avoid the effect of the chemical C/N gradient on the strain distributions over sin 2 ψ. It was found that compressive stresses induced by top blasting on the coating are released after the individual thermal cycle. During heating and cooling, part of the Ti(C,N) coating was oxidized into a TiO 2 rutile phase.

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Filtro de roca basáltica para agua residual

Filtro de roca basáltica para agua residual

con este valor se conoce la cantidad de la roca basáltica que es necesaria para ocuparlo de filtro conociendo la concentración de los elementos químicos del agua. Es muy práctico utilizar esta roca para la adsorción para agua contaminada, ya que es un recurso natural sin ningún costo. Si el agua residual solo tuviera manganeso 0.03 ppm y hierro a 0.103 ppm, entonces se necesitaría 313.95 g de roca basáltica para eliminar estos elementos químicos.

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Simulation of Temperatures and Stresses during Construction of a RCC Dam

Simulation of Temperatures and Stresses during Construction of a RCC Dam

Analyses have been presented spanning the construction and one additional year of the Cuira dam, to be built with roller compacted concrete. The calculations are particularly concerned with the possibility of cracking the outer surfaces of the dam and the possible development of excessive tensile stresses in the longitudinal direction if the distance between vertical joints is inadequate. Different cooling strategies were considered to judge their interest. As a result of the analyses conducted the following conclusions were reached:

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Stresses in steel wire ropes transversely impacted by a punctual mass

Stresses in steel wire ropes transversely impacted by a punctual mass

A deeper understanding in the transverse impact of wire ropes is required to be able to design more and improved structures to reduce the soaring loss of human lifes in traffic accident, by fall of object in mines and the huge amount of rockfalls and landslides ubiquitous all along the rugged geography that we have. By all these reasons, in this thesis are given the mathematical models of the forces in the ends of a steel wire rope and the movement of the body that impact transversely in its middle point. To achieve these objectives, both ends of the wire rope are considered rigidly fixed, reducing its geometry to an unidimensional elastic string and modeling the body as a material point that could be a rock, automobile or any machinery that could fall over a protection barrier, achieving this way a high level of acceleration what in turn induces large displacements and internal stresses around the contact zone in the wire rope. Next the models are validated using the developed equations to calculate the reaction of the steel wire ropes type 3x7 and 1x7, assuming equal conditions imposed in previous investigations done about protection barriers. At the end is concluded that all models, excepting the model of internal stresses, express the physics present in the referred experiments and simulations thus contributing to augment our knowledge about the transversal impact of steel wire ropes. And additionally, it has been contributed with a method to determine the frontier conditions in a transversely impacted string that can also be used as basis to solve more general problems, as the oblique impact of wire ropes.

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Mejoramiento de   suelos arenosos del  sector santo  domingo del valle santa catalina mediante el uso de lodo  residual municipal estabilizado

Mejoramiento de suelos arenosos del sector santo domingo del valle santa catalina mediante el uso de lodo residual municipal estabilizado

La finalidad del presente trabajo consistió en usar el lodo residual municipal estabilizado de la laguna facultativa de la Planta de Tratamiento de Aguas Residuales COVICORTI –Trujillo para mejorar el suelo arenoso del Sector Santo Domingo del Valle Santa Catalina – La Libertad. El lodo residual se añadió en 5 dosis comprendidos entre 10 a 70 toneladas de lodo por hectárea de suelo arenoso, calculados en base al requerimiento de nitrógeno, para producir una tonelada de maíz híbrido amarillo duro, variedad 'Marginal 28 Tropical'. Se determinó que el agregado de lodo residual estabilizado a dosis de 50 t/ha al suelo arenoso mejora los contenidos de materia orgánica de 0,08 a 1,83%; fósforo, de 100 a 647 mg/kg; nitrógeno, de 0,012 a 0,150 %; potasio de 160 a 185 mg/kg. También mejoró considerablemente la conductividad hidráulica, de 11,55 a 3,24 m/d; la densidad aparente de 1,6207 disminuyó a 1,0317 g/cm 3 ; la retención hidráulica aumentó de 24,2 a 59,0% y la porosidad, de 44,6 se incrementó a 63,50 %. Se concluye que la adición de lodo residual estabilizado mejora las propiedades químicas y físicas del suelo arenoso y lo transforma en apropiado para usos agrícolas. Se determinó que el rendimiento en maíz se incrementa gradualmente con la adicción de lodo residual al terreno arenoso. Se demostró que la mejor dosis es de 50 t/ha, la cual incrementa el rendimiento en grano de maíz en 472,2 por ciento en relación a la fertilización química.

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