A contribution for the improvement in thermal insulation of tabique walls coated with metal corrugated sheets

Tabique is a traditional Portuguese building technique using timber and earth and was intensively applied until the 20th century. There is an impressive tabique heritage that requires maintenance and rehabilitation interventions. Taking into account the facts that technical and scientific publications related to this particular technique are lacking and that the technique is also applied worldwide, this research work is a very relevant one. This study aims at studying the thermal insulation behaviour of tabique walls and in particular, tabique walls coated using metal corrugated sheets and thermally reinforced with an insulation material. This type of building component is initially characterized and some building details concerning the metal corrugated sheet coating are described. An experimental work was conducted to determine the thermal transmission coefficient of the tabique wall samples. It was concluded that providing the tabique wall coated with metal corrugated sheets with a 3 cm extruded polystyrene board results in a thermal insulation improvement of 61%. These results revealed that the thermal insulation reinforcement of tabique walls is possible and it may be a straightforward building procedure because it can be achieved using the thermal insulation building materials that are currently being used. Therefore, the thermal insulation reinforcement of tabique walls seems feasible. Furthermore, the thermal insulation parameters obtained in this study are similar to the ones obtained for currently applied walls solutions in new buildings. This technical fact may provide guidance for the possibility of using solutions used in old buildings to meet the thermal comfort requirements expected in today’s times. The knowledge gained will also be useful to support future proposals of energy rehabilitation solutions.info:eu-repo/semantics/publishedVersio

Correlação entre ensaios com câmara termográfica e resistógrafo na avaliação da integridade de vigas antigas de madeira

Este trabalho de investigação pretende dar um contributo no campo das técnicas não destrutivas de inspecção e de diagnóstico de vigas antigas de madeira. Para o efeito, correlacionou-se os resultados obtidos através do uso do resistógrafo e da termografia no estudo de uma viga recolhida num edifício de habitação unifamiliar que foi sujeito a um processo de remodelação. Verificou-se que poderá haver uma cerca correlação entre ensaios. Contudo, também se recomenda a realização de um número mais expressivo de ensaios de amostras para ser possível apresentar uma conclusão mais fidedigna. A relevância desta possível correlação prende-se com o facto de poder haver uma alternância na realização destes ensaios consoante os condicionalismos do cenário de obra

A contribution to the thermal insulation performance characterization of corn cob particleboards

An alternative expedite experimental set-up is proposed to evaluate the thermal insulation performance of corn cob particleboards. Testing in situ thermal insulation performance under real thermal and hygrometric conditions, using more realistic sample dimensions, testing simultaneously several samples and monitoring continuously for several days the thermal behavior of a product are some advantages of this proposed technique. Therefore, it has shown to be accurate and versatile. Through this experimental methodology, a parametric thermal insulation study of the corn cob particleboard in which the impact of its thickness on its thermal insulation performance was also possible to perform. © 2011 Elsevier B.V

Optical fiber relative humidity sensor based on a FBG with a di-ureasil coating

In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values (15.0–95.0%) of the surrounding environment, allowing an increased sensitivity (22.2 pm/%RH) and durability due to the presence of a siliceous-based inorganic component. The developed sensor was tested in a real structure health monitoring essay, in which the RH inside two concrete blocks with different porosity values was measured over 1 year. The results demonstrated the potential of the proposed optical sensor in the monitoring of civil engineering structures

DNA Damage Responses in Human Induced Pluripotent Stem Cells and Embryonic Stem Cells

BACKGROUND: Induced pluripotent stem (iPS) cells have the capability to undergo self-renewal and differentiation into all somatic cell types. Since they can be produced through somatic cell reprogramming, which uses a defined set of transcription factors, iPS cells represent important sources of patient-specific cells for clinical applications. However, before these cells can be used in therapeutic designs, it is essential to understand their genetic stability.\ud \ud METHODOLOGY/PRINCIPAL FINDINGS: Here, we describe DNA damage responses in human iPS cells. We observe hypersensitivity to DNA damaging agents resulting in rapid induction of apoptosis after γ-irradiation. Expression of pluripotency factors does not appear to be diminished after irradiation in iPS cells. Following irradiation, iPS cells activate checkpoint signaling, evidenced by phosphorylation of ATM, NBS1, CHEK2, and TP53, localization of ATM to the double strand breaks (DSB), and localization of TP53 to the nucleus of NANOG-positive cells. We demonstrate that iPS cells temporary arrest cell cycle progression in the G(2) phase of the cell cycle, displaying a lack of the G(1)/S cell cycle arrest similar to human embryonic stem (ES) cells. Furthermore, both cell types remove DSB within six hours of γ-irradiation, form RAD51 foci and exhibit sister chromatid exchanges suggesting homologous recombination repair. Finally, we report elevated expression of genes involved in DNA damage signaling, checkpoint function, and repair of various types of DNA lesions in ES and iPS cells relative to their differentiated counterparts.\ud \ud CONCLUSIONS/SIGNIFICANCE: High degrees of similarity in DNA damage responses between ES and iPS cells were found. Even though reprogramming did not alter checkpoint signaling following DNA damage, dramatic changes in cell cycle structure, including a high percentage of cells in the S phase, increased radiosensitivity and loss of DNA damage-induced G(1)/S cell cycle arrest, were observed in stem cells generated by induced pluripotency.\ud \u

Reinventing the Neural Crest: Direct Reprogramming Makes iNCCs

Aberrant neural crest (NC) development is at the origin of many congenital diseases. Given the limitations in human NC cell isolation and expansion, the development of new strategies for NC generation is crucial. In this issue of Cell Stem Cell, Kim et al. (2014) report the direct reprogramming of postnatal fibroblasts into multipotent NC cells

Modulação mitochondrial da pluripotência em células estaminais embrionárias humanas

Tese de doutoramento em Biologia Celular, apresentada à Fac. de Ciências e Tecnologia da Universidade de Coimbr

Generating melanocytes from human pluripotent stem cells

Coverage on: Mica, Y., Lee, G., Chambers, S. M., Tomishima, M. J., and Studer, L. (2013). Modeling Neural Crest Induction, Melanocyte Specification, and Disease-Related Pigmentation Defects in hESCs and Patient-Specific iPSCS. Cell Reports 3, 1140-1152. Epidermal melanocytes are pigment-producing cells derived from the neural crest (NC), a transient embryonic stem cell population that emerges from the dorsal margin of the neural plate in vertebrate embryos. The generation of melanocytes encompasses several intricate cellular processes including fate specification, proliferation, migration, and differentiation. Aberrant melanocyte development and homeostasis is at the onset of many pigmentary disorders, such as albinism, piebaldism, vitiligo, hyperplasia, and melanoma. Therefore, understanding human melanocytic development and disease is crucial. To this end, the establishment of methods that facilitate the study of patient-specific melanocyte biology and disease modeling is important

Revestimentos tradicionais de paredes de tabique e respetivos impactos no desempenho térmico

Este trabalho de investigação centrou-se no estudo experimental do desempenho térmico de sistemas construtivos tradicionais de paredes de tabique. Para o efeito, diferentes modelos de paredes de tabique foram construídos e ensaiados termicamente em laboratório. Geralmente, uma parede de tabique é um elemento construtivo caracterizado por apresentar um sistema estrutural de madeira que é revestido por terra ou por uma argamassa terrosa bastarda. Uma parede de tabique pode ser divisória ou exterior e, em ambos os casos, ela pode desempenhar uma importante função estrutural. O facto de uma parede de tabique exterior estar exposta à intempérie, aumenta a sua vulnerabilidade patológica, e justifica a aplicação complementar de um revestimento exterior. Os sistemas construtivos de revestimento exterior do tipo simples, mais frequentemente aplicadas são a chapa metálica ondulada e os soletos de ardósia. Estas foram as soluções tradicionais de revestimento exterior alvo de estudo. Os materiais considerados foram recolhidos em obra e aplicados de forma análoga ao construído tradicionalmente. Deste modo, foi possível aferir o desempenho térmico destas soluções construtivas. Atendendo a que a construção de tabique é relevante no panorama do património construído Português, este trabalho de investigação poderá dar um contributo valioso para o conhecimento desta técnica construtiva e, simultaneamente para o auxílio de processos de reabilitação e de reforço térmico deste tipo de edifícios.info:eu-repo/semantics/publishedVersio

Traditional coatings of tabique walls and their thermal insulation contribution

This research work is focused on studying the thermal behaviour of traditional tabique wall systems. Therefore, different tabique wall samples were built and their thermal behaviour was experimentally assessed in laboratory. In general, a tabique wall system is formed by a timber structure frame which is filled with earth or an earth based render. A tabique wall may be exterior or partition. In both cases, it may have a contribution in the overall structural behaviour of a building. At the same time, the fact that a tabique wall may be exterior increases its pathology likelihood and justifies the application of a complementary exterior coating such as metal corrugated sheets or schist tiles. These were the studied traditional building solutions in terms of thermal insulation behaviour. The wall samples were prepared with materials which were collected from tabique buildings and they were applied according to the traditional techniques. The obtained outputs may contribute for the knowledge of this traditional building technique and they may be helpful in rehabilitation processes of this type of building, in particular, concerning thermal insulation improvement.info:eu-repo/semantics/publishedVersio