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The processing parameters to obtain a laminate consisting of very thin alumina-aluminium titanate crack deflecting layered structures sandwiched between relatively thick load bearing alumina layers are described. The optimum processing conditions for the insertion of reactive layers to improve joining during sintering have been established. Pre-sintered alumina tapes were used as the load bearing components while the internal structures were shaped by a combination of electrophoretic deposition (EPD) and dipping. The dipped layers acted as reactive layers during sintering. The thickness of the dipped layers has to be controlled in order to avoid the disappearance of the EPD structure during sintering as well as the cracking of the coating during drying or handling. The specimens were mechanically tested in three points bending with the applied load perpendicular to the layers and the fracture surfaces were observed by scanning electron microscopy. The obtained structure presents crack deflection at the microstructural scale during fracture which confers it flaw tolerance.Se describen los parámetros de procesamiento mas adecuados para obtener laminados constituidos por capas finas de alúmina-titanato de aluminio deflectoras de grietas alternadas con capas gruesas de alúmina resistentes a las cargas. Estas últimas se han fabricado a partir de láminas obtenidas por colaje en cinta y presintetizadas. Las estructuras con capacidad para la deflexión de las grietas se conformaron mediante una combinación de deposición electroforética e inmersión. Se han establecido las condiciones óptimas para que las capas obtenidas por inmersión actúen como capas reactivas durante la sinterización, sin que desaparezca la estructura EPD durante la sinterización ni se produzca el agrietamiento durante el secado y la manipulación de la estructura. El comportamiento mecánico de las estructuras laminadas obtenidas se analizó mediante ensayos de flexión en tres puntos, con la carga aplicada en la dirección perpendicular a la superficie de las capas, y observaciones fractográficas. La estructura óptima obtenida es tolerante a las grietas debido a la deflexión de éstas por las capas internas durante la fractura.

The use of ceramic materials in structural applications is limited by the lack of reliability associated with brittle fracture behaviour. In order to extend the structural use of ceramics, the design of microstructures which exhibit flaw tolerance due to toughening mechanisms which produce an increase in crack growth resistance during crack propagation has been proposed. This work is a review of the mechanical behaviour of structural ceramic materials and its characterisation. Firstly, the basic brittle fracture parameters and the statistical criteria to determine the probability of exceeding the safety factors demanded for a particular application are analysed. Then, the toughening mechanisms which can be developed in the materials through microstructural design as well as the mechanical characterisation of toughened ceramics are discussed. The experimental values of linear elastic fracture toughness parameters (critical stress intensity factor, KIC, and critical energy release rate, GIC) are not intrinsic properties for toughened materials and depend on crack length and the loading system. In this work, the different mechanical parameters proposed to characterise such materials are reviewed. The following fracture parameters are analysed: work of fracture (γWOF), critical J-integral value (JIC) and R-curve. For the determination, stable fracture tests are proposed in order to ensure that the energy provided during the test is no more than the necessary one for crack propagation.El uso de los materiales cerámicos en aplicaciones estructurales está limitado por la falta de fiabilidad asociada a su comportamiento frágil durante la fractura. Para extender su aplicación se ha propuesto el diseño de microestructuras que presenten tolerancia a los defectos debido a la actuación de mecanismos de refuerzo. Este trabajo es una puesta al día sobre el estudio del comportamiento mecánico de los materiales cerámicos estructurales y su caracterización. En primer lugar, se revisan los parámetros de fractura utilizados para caracterizar materiales frágiles y los criterios de control estadístico que permiten determinar la probabilidad de que se sobrepasen los factores de seguridad exigidos en cada aplicación. A continuación, se discuten los mecanismos de refuerzo que se pueden desarrollar en los materiales cerámicos a través del diseño microestructural. En los materiales cerámicos en los que la actuación de mecanismos de refuerzo conduce a un comportamiento significativamente distinto del puramente frágil, los parámetros derivados del tratamiento lineal elástico (factor crítico de intensidad de tensiones, KIC, y tasa crítica de liberación de energía, GIC), determinados experimentalmente, dejan de ser propiedades intrínsecas del material, independientes del tamaño de grieta y el sistema de carga. El presente trabajo revisa los parámetros mecánicos propuestos para la evaluación de la tenacidad de fractura de los materiales cerámicos reforzados y los métodos utilizados para su determinación. Se analizan los siguientes parámetros mecánicos: trabajo de fractura (γWOF), valor crítico de la integral J (JIC) y curva R. Para su determinación se proponen ensayos de fractura estable, que aseguran que la energía suministrada durante el ensayo se emplea únicamente en la propagación de la grieta.

Arthroplasty with discectomy is a proven treatment for internal derangement of the temporomandibular joint (TMJ), however there is no consensus on the type of interpositional graft that should be used after the disc is removed. While an ideal graft should be easy to obtain and provide an adequate buffer between the articular surfaces, the authors suggest that it should also minimize donor site morbidity. This Technical Note highlights the technique for harvesting and utilizing the superficial musculoaponeurotic system (SMAS) as an interpositional graft. Three patients were treated with a SMAS graft after TMJ arthroplasty with discectomy. The average pain score decreased from 9/10 preoperatively to 2/10 at 6 weeks postoperatively, while the average maximum incisal opening increased from 31 mm to 36.7 mm. Since these patients were concurrently treated with a facelift, they were asked about their esthetic outcome on a scale of 1–10, with 1 representing extremely dissatisfied and 10 representing extremely satisfied. The average esthetic rating at 6 weeks postoperatively was 9.3/10. The SMAS interpositional graft technique eliminates a second surgical site, improves function, reduces pain, and provides the opportunity for concurrent esthetic facial rejuvenation if desired. [ABSTRACT FROM AUTHOR]

The effects of tensile strain on the current-voltage (I-V) characteristics of hydrogenated-edge armchair graphene nanoribbons are investigated by using DFT theory. The strain is introduced in two different ways related to the two types of systems studied in this work: in-plane strained systems (A) and out-of-plane strained systems due to bending (B). These two kinds of strain lead to make a distinction among three cases: in-plane strained systems with strained electrodes (A1) and with unstrained electrodes (A2), and out-of-plane homogeneously strained systems with unstrained, fixed electrodes (B). The systematic simulations to calculate the electronic transmission between two electrodes were focused on systems of 8 and 11 dimers in width. The results show that the differences between cases A2 and B are negligible, even though the strain mechanisms are different: in the plane case, the strain is uniaxial along its length; while in the bent case, the strain is caused by the arc deformation. Based on the study, a new type of nanoelectromechanical system solid state switching device is proposed. [ABSTRACT FROM AUTHOR]

We explore the dynamics of a graphene nanomechanical oscillator coupled to a reference oscillator. Circular graphene drums are forced into self-oscillation, at a frequency fosc, by means of photothermal feedback induced by illuminating the drum with a continuous-wave red laser beam. Synchronization to a reference signal, at a frequency fsync, is achieved by shining a power-modulated blue laser onto the structure. We investigate two regimes of synchronization as a function of both detuning and signal strength for direct (fsync ≈ fosc) and parametric locking (fsync ≈ 2fosc). We detect a regime of phase resonance, where the phase of the oscillator behaves as an underdamped second-order system, with the natural frequency of the phase resonance showing a clear power-law dependence on the locking signal strength. The phase resonance is qualitatively reproduced using a forced van der Pol-Duffing-Mathieu equation. [ABSTRACT FROM AUTHOR]

The postnatal ultrasound findings were bilateral hydronephrosis and hiperechogenic parenchymal texture of the kidneys, normal bladder and abdominal hipoechogenic cyst. There is a strong association between malformations of the urinary system and the genital tract. On 31 week's gestation the amniotic fluid has become normal (AFI =15.0 cm), but the kidneys findings were the same. [Extracted from the article]

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A parallel group randomized trial was designed to analyze the impact of 6 weeks of strength training programs performed with or without whole-body vibration on muscular and endurance performance parameters in long-distance runners. 22 endurance runners were allocated into strength with whole-body vibration (n = 8), without (n = 8), and control (n = 6) groups. Before and after the experimental period the subjects performed the following tests: a) maximum dynamic strength test, b) maximal incremental treadmill test, and c) time to exhaustion at velocity corresponding to maximal oxygen uptake. The fractions of the aerobic and anaerobic contribution in time to exhaustion test were also calculated. Both strength trained groups showed a similar increase in maximum dynamic strength (~18 %). The aerobic contribution was enhanced for strength training group without whole-body vibration (~25 %) after experimental period. No statistical differences were observed in any other variable. These results suggest that 6 weeks of strength training performed with or without whole-body vibration improve similarly the maximum dynamic strength in long-distance runners. In addition, both training modes studied had no deleterious effects on the traditional parameters of endurance performance, traditional strength training program results in increased aerobic contribution during high-intensity aerobic exercise. [ABSTRACT FROM AUTHOR]

A group of high strength, cost effective PM steels has been generated by combining alloying elements (e.g. Cr, Mo, Ni, Cu, Mn) in predetermined concentrations. The main aim was to optimise the balance between compress- ibility, hardenability and properties. Special efforts were devoted to identify-ing compositions and processing conditions giving specific proportions of transformation products (martensite, bainite, etc.) in an attempt to correlate microstructural characteristics with the mechanical properties of the sintered steels after tempering. Measuring dimensional changes after sintering as well as properties such as yield stress and hardness allowed processing conditions to be optimised for the composition and characteristics of the powder mixture. [ABSTRACT FROM AUTHOR]

Priming facilitation was examined under conditions of brief incremental prime exposures (28, 43, 71, and 199 msec) under masked conditions for two types of lexical relationships (associative-semantic pairs, such as 'wolf-fox,' and semantic-feature pairs, such as 'whale-dolphin') and in two tasks (primed lexical decision and semantic categorization). The results of eight experiments revealed, first, that priming elicits faster response times for semantic-feature pairs. The associative-semantic pairs produced priming only at the longer prime exposures. Second, priming was observed earlier for semantic categorization than for the lexical decision task, in which priming was observed only at the longer stimulus onset asynchronies. Finally, our results allowed us to discredit the congruency hypothesis, according to which priming is due to a common categorical response for the prime and target words. The implications of these results for current theories of semantic priming are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Alumina+10vol.% aluminium titanate composites were obtained by colloidal filtration and reaction sintering of alumina and titania. The materials were dense with aluminium titanate grains of average sizes 2.2–2.4μm located mainly at alumina triple points. The reaction sintering schedule promoted the formation of additional nanometric grains, identified as aluminium titanate using STEM–EDX analysis between the alumina grains. This special microstructure led to a change of the toughening mechanism from the typical crack bridging reported for microcrack-free composites fabricated from alumina and aluminium titanate powders to microcracking. The identification of microcracking as the main toughening mechanism was done from the analysis of stable fracture tests of SENVB samples in three points bending and fractographic observations. Monophase alumina materials with similar grain sizes were used as reference. Different fracture toughness parameters were derived from the load–displacement curves: the critical stress intensity factor, K IC, the critical energy release rate, G IC, the J-Integral and the work of fracture, γ WOF, and the R curves were also built. The comparison between the linear elastic fracture parameters and the non-linear ones revealed significant toughening and flaw tolerance. [Copyright &y& Elsevier]

The article discusses pemphigoid, an autoimmune disease with autoantibodies which appear against the basement membrane of the epithelium. It explains the difference between bullous and cicatricial pemphigoid. It cites the importance of examining tissue specimen and conducting immunofluorescence to patients in order to distinguish benign mucosal periphigoid from lesions with Nikolsky symptom. It states that intraoral lesions do not respond to topical and systemic corticosteroids treatment.

Dense and microcrack-free Al2O3/Al2TiO5 composites (10, 30 and 40 vol.% of Al2TiO5) have been obtained by colloidal filtration and reaction sintering, using alumina and titania as starting powders. The processing of the composites has been studied focusing on the rheological behaviour of aqueous suspensions of each powder and of mixtures. Colloidal filtration of optimised suspensions, with a solid loading as high as 50 vol.%, and a thermal treatment at 1450 °C, lead to completely reacted and uncracked sintered materials with homogeneously distributed aluminium titanate contents up to 40 vol.% and high density. Thermal diffusivity values from 25 to 800 °C are coincident on heating and cooling for the three studied composites, and decrease with temperature and with aluminium titanate content. [Copyright &y& Elsevier]

A análise de Theodor W. Adorno ao fascismo aparece como um dos temas mais importantes da Teoria Crítica, pois esse filósofo dedicou ao assunto uma parte expressiva de sua obra intelectual. Nessa reflexão, o conceito freudiano de unheimlich teve um papel fundamental, pois permitiu a compreensão da relação ambivalente no que diz respeito a estranhos e estrangeiros, na consideração de que o diferente repele e ao mesmo tempo é internamente familiar. Na análise crítica de Adorno sobre o fascismo, a estigmatização da diferença, impulsionada pela incapacidade de compreensão e aceitação dos próprios conteúdos pulsionais do sujeito, acarreta o desenvolvimento de fortes tendências de segregação, que adquirem coloração fascista sempre que se manifestam como oposições in-group e out-group. Este artigo pretende repercutir a importância dessa análise no campo educativo, em especial no que se refere a possibilidades autorreflexivas no campo formativo

Ecological and economic demands are driving PM markets to incorporate less expensive, yet effective, alloying elements in iron based powders. To investigate their potential for this purpose recently developed sinter-hardening iron powders containing Cr and smaller amounts of Mo and Ni were industrially sintered at 1120 and at 1240°C under laboratory conditions. One set of samples, containing 0·8% graphite additions, was cooled so to obtain sinter-hardened steels. A second set of samples, containing 0·3% graphite, was cooled under normal conditions and subjected to a secondary carburising treatment. The microstructures and mechanical properties developed were compared. [ABSTRACT FROM AUTHOR]

O presente artigo tem por objetivo problematizar dialeticamente o tema da diferença de acordo com os conceitos da teoria crítica. Em um primeiro momento, o tema da diferença será pensado em sua recepção negativa referida à produção de estereótipos e preconceitos de natureza étnica, racial e de gênero. Em um segundo momento, o tema será tratado em sua recepção positiva, muito comum entre movimentos sociais de esquerda e meios acadêmicos. Em um terceiro momento, ambos os tipos de recepção da diferença serão problematizados a partir do pensamento de Theodor Adorno, em sua Dialética negativa, como possível via de mediação entre a particularidade empírica e a universalidade conceitual

The article discusses a study conducted to describe a case series of five patients with panfacial fractures (PFF) associated with type III-nasoorbitethmoid (NOE) fractures, providing treatment guidelines with the use of a titanium plate to reconstruct the nasal dorsum.

The article aims to describe a case series of large penetrating orbital trauma providing treatment guidelines associated with a review of English language literature of large foreign bodies into the orbit from 1997 to 2017.

The article reports that the surgical management of the maxillofacial trauma can directly influence the aesthetics and function of the face and notes that the study aims to describe 11 cases where local flaps(LF) are used for facial trauma reconstruction.