Effects of Wood Density And Interlocked Grain on the Shear Strength of Three Amazonian Tropical Hardwoods

Three tropical hardwoods, ishpingo (Amburana cearensis A.C. Smith), pumaquiro (Aspidosperma macrocarpon Mart.), and tulpay (Clarisia racemosa Ruiz and Pav.), were studied to determine the effects of wood density and interlocked grain on the shear strength parallel to grain. The maximum angular deviation (MAD) and the interlocked grain index (IG) were used to evaluate interlocked grain. The parameters were determined for interlocked grain samples and for ASTM D 143 shear blocks. There was a strong relationship between the interlocked grain parameters for the three species. MAD was simpler to evaluate compared to IG. The interlocked grain was highly variable within wood species. Failure of sheared blocks was irregular and in general followed the interlocked grain pattern. Hence, apparent shear strength was calculated using either a measured shear area (actual shear strength) or a fixed shear area of 2500 mm2 (nominal shear strength). Wood density positively affected the apparent shear strength of the wood. The relationships were stronger for actual shear strength compared to nominal shear strength. For all species studied, the interlocked grain negatively affected actual shear strength. The relationships between nominal shear strength and interlocked grain parameters were positive for ishpingo and tulpay, but negative for pumaquiro. Finally, we concluded that the ASTM D 143 block shear test method should be adapted for woods with heavily interlocked grain

Changes in Physical Properties of Yellow Birch Below and Above the Fiber Saturation Point

Two experimental techniques were used to perform moisture sorption tests at 25°C on specimens of yellow birch sapwood. The first used saturated salt solutions (from 33% to 90% relative humidity), and the second used the pressure membrane method (above 96% relative humidity). These sorption tests were combined with dimensional measurements and perpendicular-to-the-grain tangential compression tests. Results showed that at equilibrium moisture content, radial, tangential, and volumetric shrinkage, as well as changes in transverse strength, occur above the fiber saturation point. This behavior can be explained by the effect of hysteresis at saturation on wood properties. This hysteresis indicates that loss of bound water takes place in the presence of liquid water, which contradicts the concept of FSP. The initial equilibrium moisture content at which bound water is removed from yellow birch was about 41%

Non-Fickian diffusion in biomaterials

[EN] The knowledge of water vapour diffusion in biomaterials is very important in several fields of application (drying, building materials, food packaging…). The process of vapour water transfer in biomaterials is usually described by Fick’s law of diffusion. Nevertheless, sometimes the experimental data of transient experiments in biosourced materials do not respect the standard Fickian model. The precise determination and formulation of this non-Fickian behaviour is therefore an important topic. This work presents a new methodology to quantify the non-Fickian diffusion. Based on memory functions and imbedded in a comprehensive heat and mass transfer computational model, the method is robust and prone to be applied to different biomaterials. Examples of application are proposed in the case of biofilms and lignocellulosic materials.Almeida, G.; Perre, P. (2018). Non-Fickian diffusion in biomaterials. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 2043-2052. https://doi.org/10.4995/IDS2018.2018.7943OCS2043205

Alteration of physico-chemical characteristics of coconut endocarp — Acrocomia aculeata — by isothermal pyrolysis in the range 250–550 °C

Characteristics of the endocarp of Acrocomia aculeata fruit samples were evaluated before and after 2 h of iso thermal pyrolysis in the range 250–550 °C. Differential thermogravimetric (DTG) curves from the char, obtained at 300 °C, confirm that degradation of hemicellulose and cellulose was complete and resulted in approximately 42.5% oxygen loss. The micrographs obtained from scanning electron microscopy with a field emission gun (SEM/FEG) confirmed a softened phase from the chars treated at 250 °C. The van Krevelen analysis shows that energy intensification of the sample transferred from peat to charcoal as the treatment intensity increased; this resulted in a 71% mass loss at 550 °C. The surface area of the treated sample increased exponentially with a factor of 1.2 per percentage of mass loss, from 450 °C and reached 216 m2 /g at 550 °C as a consequence of the development of microporous structures. The water-vapor-sorption properties were strongly affected by the treatment, with a pronounced type V isotherm curve for the char at 550 °C. These results show the evolution in chemical and structural properties of coconut endocarp during its isothermal pyrolysis. In particular, the im proved char properties indicate that this material may be used as solid fuel or as raw material for the gasification process.CONACYT - Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Mídias digitais e qualidade da interação mãe-bebê: revisão de literatura

A qualidade da interação mãe-bebê é estruturante para o desenvolvimento da criança. Cada vez mais, nota-se que as mídias digitais estão fortemente presentes na vida familiar. A investigação da qualidade da interação mãe-bebê no contexto atual, marcado por essas novas mídias, é essencial para conhecer seus possíveis impactos. A partir disso, esse estudo objetivou realizar uma revisão de literatura científica e sistematizar conhecimentos sobre o uso de mídias digitais e a qualidade da interação mãe-bebê. Foram realizadas buscas nas bases de dados PsycINFO, ERIC, Scopus e Pubmed. Os resultados mostraram que a interação mãe-bebê tem sido estudada, primordialmente, em três situações: a) comparativamente entre leitura de livros impressos e e-books; b) comparativamente entre brinquedos tradicionais e digitais e; c) em momentos da rotina. De acordo com os achados, observa-se que as mídias digitais tendem a influenciar negativamente a interação mãe-bebê, ainda que algumas vantagens dos recursos eletrônicos sejam apontadas. Discute-se a necessidade de mais estudos que possam investigar o fenômeno, considerando a relevância da interação mãe-bebê para o desenvolvimento humano

Digital media and quality of mother-baby interaction : literature review

A qualidade da interação mãe-bebê é estruturante para o desenvolvimento da criança. Cada vez mais, nota-se que as mídias digitais estão fortemente presentes na vida familiar. A investigação da qualidade da interação mãe-bebê no contexto atual, marcado por essas novas mídias, é essencial para conhecer seus possíveis impactos. A partir disso, esse estudo objetivou realizar uma revisão de literatura científica e sistematizar conhecimentos sobre o uso de mídias digitais e a qualidade da interação mãe-bebê. Foram realizadas buscas nas bases de dados PsycINFO, ERIC, Scopus e Pubmed. Os resultados mostraram que a interação mãe-bebê tem sido estudada, primordialmente, em três situações: a) comparativamente entre leitura de livros impressos e e-books; b) comparativamente entre brinquedos tradicionais e digitais e; c) em momentos da rotina. De acordo com os achados, observa-se que as mídias digitais tendem a influenciar negativamente a interação mãe-bebê, ainda que algumas vantagens dos recursos eletrônicos sejam apontadas. Discute-se a necessidade de mais estudos que possam investigar o fenômeno, considerando a relevância da interação mãe-bebê para o desenvolvimento humano.Introduction: The quality of the mother-baby interaction is essential for the child’s development. It is noted that digital media are strongly present in family relations. The investigation of the quality of mother-baby interaction in the current context, marked by these new media, is essential to know its possible impacts. Objective: Based on this, we performed a literature review and systematize scientifi c knowledge on use of digital media and the quality of mother-baby interaction. Material and Methods: The databases consulted were PsycINFO, ERIC, Scopus and Pubmed. Results: The results showed that the mother-baby interaction has been studied, mainly, in three situations: a) comparatively between traditional and digital books; b) comparatively between traditional and digital toys and; c) during the routine. According to the results, digital media tend to negatively infl uence mother-baby interaction, although some advantages of electronic resources are pointed out. Conclusion: The need for further studies that can investigate the phenomenon nationally is discussed, considering the relevance of motherbaby interaction for human development

Modélisation de la viscosité de suspensions de particules molles végétales et observation directe des particules en milieu encombré

Les pure?es de pommes sont des suspensions concentre?es de particules non colloi?dales (180 ?m), non- sphe?riques et tre?s de?formables. Ces particules sont de?limite?es par une paroi cellulaire ve?ge?tale et remplies par la phase continue. Sous contrainte ou lorsque la concentration en particules augmente, elles se compriment, ce qui rend difficile la de?termination de leur fraction volumique re?elle et la compre?hension de leurs proprie?te?s rhe?ologiques. En ge?ne?ral, le comportement rhe?ologique des suspensions de particules ve?ge?tales est de?crit par trois domaines de concentration : un domaine dilue? dans lequel les particules interagissent peu (newtonien), un domaine interme?diaire marque? par l'apparition d'un re?seau entre les particules (comportement de fluide a? seuil, caracte?rise? par un module e?lastique a? faible de?formation qui augmente fortement avec la concentration en particules) et un domaine concentre? dans lequel les particules sont contraintes de se de?former pour s'adapter a? l'espace environnant et permettre l'e?coulement (le module e?lastique est de l'ordre de 103 Pa et la de?pendance a? la concentration en particules diminue). En combinant microscopie confocale et reconstruction 3D, nous avons de?veloppe?? un protocole pour de?terminer le volume de cellules dans des suspensions concentre?es de particules ve?ge?tales. Ce travail a permis de mettre en e?vidence que le volume des cellules diminue uniquement dans les suspensions fortement concentre?es. Par observation directe au sein de l'e?chantillon, nous apportons ainsi la preuve de la capacite?? des particules ve?ge?tales a? se comprimer et a? diminuer ainsi leur volume lorsque la concentration augmente. Dans ce travail, nous proposons e?galement un moyen d'acce?der a? la fraction volumique apparente des particules et un mode?le de?crivant la de?pendance de la viscosite? a? la concentration sur une large plage de concentrations. Le mode?le propose?, adapte? du mode?le de Mendoza (Mendoza 2013), s'ajuste avec pre?cision aux re?sultats expe?rimentaux obtenus sur des pure?es de pommes de distribution granulome?trique variable et sur des suspensions mode?les reconstitue?es dans plusieurs phases continues. Les parame?tres du mode?le refle?tent la rigidite? et l'asphe?ricite? des particules. Ce travail offre des perspectives inte?ressantes pour l'industrie des fruits et le?gumes transforme?s et a permis une avance?e vers la mode?lisation de ces syste?mes. Re?fe?rences : Day L., Xu M., Øiseth S.K., Hemar Y. & Lundin L. (2010). Control of Morphological and Rheological Properties of Carrot Cell Wall Particle Dispersions through Processing. Food and Bioprocess Technology, 3(6), 928?934. doi :10.1007/s11947-010-0346-0. Espinosa-Mun?oz L., Renard C., Symoneaux R., Biau N. & Cuvelier G. (2013). Structural parameters that determine the rheological properties of apple puree. Journal of Food Engineering, 119(3), 619?626. doi :10.1016/j.jfoodeng.2013.06.014. Mendoza C.I. (2013). Model for the Shear Viscosity of Suspensions of Star Polymers and Other Soft Particles. Macromolecular Chemistry and Physics, 214(5), 599?604. doi :10.1002/macp.201200551

Construcción de significados en la pérdida gestacional: estudio cualitativo con parejas brasileñas

We investigated the process of meaning construction in pregnancy loss in 11 Brazilian couples. The reports were submitted to inductive and deductive thematic analysis using the categorization system from the integrative model of meaning construction in grief. Regarding the original dimensions of the model (Sense-making of death, benefit from the experience of loss, and identity change), there was a lack of meaning for death, perception of strengthened bonds within the couple as a benefit, and parenting as an identity project. We propose an additional dimension (Meaning-making process) that includes gender differences, lack of social recognition, and emotional intensity of the experience. As for coping strategies, spirituality and the search for peers were identified, especially in social media. After a pregnancy loss, the process of meaning construction proved similar to that of other types of loss, validating this experience. We discuss the implications of the category system used in this study.Investigou-se o processo de construção de significados na perda gestacional em 11 casais brasileiros. Os relatos foram submetidos à análise temática indutiva e dedutiva, utilizando o sistema de categorização do modelo integrativo de construção de significado no luto. Em relação às dimensões originais do modelo (Sentido para a morte, benefício na experiência de perda e modificação da identidade), constatou-se falta de sentido para a morte, fortalecimento de vínculo do casal como benefício e parentalidade enquanto projeto identitário. Foi proposta uma dimensão adicional (Processo de construir significado) que incluiu diferenças de gênero, falta de reconhecimento social e intensidade emocional da experiência. Enquanto estratégias de enfrentamento, identificou-se espiritualidade e busca por iguais, especialmente nas mídias sociais. O processo de construir significados na perda gestacional mostrou-se semelhante ao de outros tipos de perdas, validando esta experiência. Foram discutidas as implicações do sistema de categorias utilizado.Se investigó el proceso de construcción de significados en la pérdida gestacional en 11 parejas brasileñas. Los informes fueron sometidos a un análisis temático inductivo y deductivo, usando el sistema de categorización del modelo integrador de construcción de significado en el duelo. En cuanto a las dimensiones originales del modelo (Significado para la muerte, beneficio en la experiencia de pérdida, cambio de identidad), se encontró falta de significado para la muerte, fortificación de lazos de la pareja como un beneficio y la parentalidad como un proyecto de identidad. Se ha propuesto una dimensión adicional (Proceso de construcción de significado) que incluye diferencias de género, falta de reconocimiento social e intensidad emocional de la experiencia. Como estrategias de afrontamiento, se identificó la espiritualidad y la búsqueda de los iguales, especialmente en las redes sociales. El proceso de construir significado en la pérdida gestacional demostró ser similar al de los otros tipos de pérdida, validando esta experiencia. Son discutidas las implicaciones del sistema de categorías utilizado

Reducing harm and promoting positive media use strategies : new perspectives in understanding the impact of preschooler media use on health and development

Most children grow up in homes with easy access to multiple screens. Screen use by children between the ages of 0 to 5 has become a worldwide preoccupation. In the present narrative review, we examine child and parent screen use and its contribution to physical, cognitive, and social developmental outcomes. As research has mostly focused on the adverse consequences of screen media, we aim to depict both the negative and the positive infuences of screen usage. To provide a more nuanced portrait of the potential benefts and harms of screen use, we examine how consequences of media use vary according to the content of media (ex., educational, violent), context (ex., using screens during mealtimes), and the nature (ex., passive vs active use) of child screen use. Our review supports existing screen time guidelines and recommendations and suggests that media content, the context of use, and the nature of child use, as well as the parent’s own screen use, be considered clinically. Future research should seek to clarify how these dimensions jointly contribute to child screen use profles and associated consequences. Finally, child sex, behavioral/temperamental difculties, and family adversity appear to contribute to child screen use and its consequences and should be considered in future research. Suggestions for harm-reduction approaches are discussed

The Imaginary Child in the Context of Waiting for Adoption

O período anterior à chegada da criança na família adotiva é permeado por expectativas, incluindo o imaginário sobre a criança. O presente estudo investigou as representações maternas sobre a criança imaginária no contexto de espera pela adoção. Trata-se de um estudo de casos múltiplos em que participaram quatro mulheres que esperavam na fila de adoção. Os dados foram analisados através da Análise Temática e organizados a partir de três temas definidos previamente: (a) imaginário sobre características físicas; (b) imaginário sobre as características emocionais; e (c) imaginário sobre a relação mãe-criança. Observou-se que no primeiro tema surgiram questões raciais, enquanto no segundo tópico as participantes falaram sobre a representação de uma criança sofrida e/ou idealizada, sendo essa última baseada na apresentação de um comportamento calmo. Na relação com a criança, as participantes abordaram a necessidade de adaptação frente ao tornar-se mãe por adoção, apesar disso, suas perspectivas apontavam para interações positivas. Reconhecer a espera pela adoção como parte da transição para parentalidade faz-se primordial para saúde emocional dessas famílias. Este estudo contribui empiricamente para uma maior compreensão sobre as representações maternas da criança imaginária no contexto da filiação adotiva.The period prior to the arrival of the child in the adoptive family is permeated by expectations, including the imaginary about the child. The present study investigated the maternal representations about the imaginary child in the context of waiting for adoption. This is multiple case studies involving four women who were waiting in line for adoption. The data were analyzed through the Thematic Analysis and organized from three previously defined themes: (a) imaginary about physical characteristics (b) imaginary about emotional characteristics and (c) imaginary about the mother-child relationship. It was observed that in the first theme racial issues arose, while in the second it oscillated between the representation of a child suffered and/or idealized as calm. In the relationship with the child, the participants approached the need for adaptation to becoming an adoptive mother, despite this, their perspectives point to positive interactions. Recognizing the waiting period to adopt as part of the transition to parenting is essential for the emotional health of these families. This study empirically contributes to a better understanding of maternal representations of the imaginary child in this context of adoptive filiation