Non communiqué. / Non communiqué.

published_or_final_version / Applied Geosciences / Master / Master of Science

This thesis discusses the results of experimental tests on two post-tensioned timber core-walls, tested under bi-directional quasi-static seismic loading. The half-scale two-storey test specimens included a stair with half-flight landings. Multi-storey timber structures are becoming increasingly desirable for architects and building owners due to their aesthetic and environmental benefits. In addition, there is increasing public pressure to have low damage structural systems with minimal business interruption after a moderate to severe seismic event. Timber has been used extensively for low-rise residential structures in the past, but has been utilised much less for multi-storey structures, traditionally limited to residential type building layouts which use light timber framing and include many walls to form a lateral load resisting system. This is undesirable for multi-storey commercial buildings which need large open spaces providing building owners with versatility in their desired floor plan. The use of Cross-Laminated Timber (CLT) panels for multi-storey timber buildings is gaining popularity throughout the world, especially for residential construction. Previous experimental testing has been done on the in-plane behaviour of single and coupled post-tensioned timber walls at the University of Canterbury and elsewhere. However, there has been very little research done on the 3D behaviour of timber walls that are orthogonal to each other and no research to date into post-tensioned CLT walls. The “high seismic option” consisted of full height post-tensioned CLT walls coupled with energy dissipating U-shaped Flexural Plates (UFPs) attached at the vertical joints between coupled wall panels and between wall panels and the steel corner columns. An alternative “low seismic option” consisted of post-tensioned CLT panels connected by screws, to provide a semi-rigid connection, allowing relative movement between the panels, producing some level of frictional energy dissipation.

La investigación se enfoca en el estudio del territorio, planificación del espacio natural y arquitecturas relacionadas con el turismo, en el que convergen aspectos sociales, económicos, ambientales y de infraestructuras sostenibles con gran dinamismo, frente a los impactos negativos generados en el paisaje. Por tal motivo, la investigación inicia a partir del estudio de la situación turística, espacio natural y la ciudad, enfocado en el caso de la comunidad campesina Santa Catalina del distrito de Chongoyape, Perú; con el objetivo de reactivar e integrar natural y socialmente a la comunidad mediante la planificación adecuada del espacio turístico natural. La metodología aplicada se enfoca en el estudio de planes de desarrollo turístico sostenible con o sin infraestructuras turísticas y recreativas de ciudades modernas, seguido de la situación del sistema turístico de Santa Catalina para su posterior comprensión, evaluando sus potencialidades y deficiencias que delimitaran las estrategias y lineamientos en la propuesta final de la investigación. La planificación conformada por un conjunto de circuitos turísticos, infraestructuras sostenibles y la propuesta de un centro ecoturístico como equipamiento recreativo – cultural y espacio para el aprendizaje y sociabilización de pobladores y turistas en la zona, permitirá alcanzar el fin principal de esta investigación. / Tesis

Thesis (M. Soc. Sc.)--University of Hong Kong, 1984.

We investigate the temperature and size distribution of Ag, Ge, CdSe and ZnS nanoparticles undergoing UV excimer laser pulses. A two laser pulse experiment is designed to monitor nanoparticle size before and after laser interaction. We study HRTEM images and measure the ablation and fluorescence spectra of particles before and after evaporation. Results show that the nanoparticle mean radius decreases from 3.4 ± 0.2 nm to 2.6 ± 0.2 nm, from 4.3 ± 0.1 nm to 3.5 ± 0.1 nm, and from 3.1 ± 0.2 nm to 2.6 ± 0.2 nm for Ag, Ge and CdSe, respectively. No ZnS nanoparticle size reduction was observed. Theoretical models for nanoparticles undergoing laser heating show that temperatures above the bulk and nanoparticle material melting point reduce the nanoparticles size by a factor of 0.3 and suggest recondensation before collection. For CdSe nanoparticles collected on dry substrates and solvents, blue shifted fluorescence (PL) peaks support the size reduction. / text

In this dissertation, I will look into the size distribution of silver nanoparticles produced by laser ablation of microparticles (LAM). I will investigate the role of both pulsed and continuously operating nozzles on the size distribution. In addition, I will examine any deviations from the previously observed log-normal size distribution for silver nanoparticles comparing previous collection techniques involving supersonic jet impaction with a current time of flight mass spectrometer (TOF-MS). These new observations will be made in situ using a Wiley-McLaren TOF-MS with a reflector and multiphoton ionization and will mainly focus on the smaller sized nanoparticles. An introduction to enhancing a second harmonic optically generated signal will also be investigated involving silver nanocomposites while utilizing a polarized crossed-beam femtosecond laser technique. / text

This thesis describes a feasibility study into the use of a new method of timber construction developed in New Zealand. This new method combines the use of an engineered wood product (Laminated Veneer Lumber) and post-tensioned ductile connections. Three case study buildings are presented in concrete, steel and timber all representing current design and construction practice. A fourth building, referred to as the “timber plus” structure, is also considered with the addition of timber architectural components. The case study timber building consists of two lateral resisting systems. In one direction post-tensioned LVL moment resisting frames are used, with post-tensioned cantilever walls in the orthogonal direction. Timber-concrete composite floor units are also used. The method of design and detailing of the timber building is shown with member sizes being found to be comparable to that of the concrete structure. Sub-assembly testing is performed on some key connections with excellent results. Construction time is evaluated and compared to the concrete structure with similar construction times being achieved. Finally the costs of the case study buildings are calculated and compared. The costing found the four options to be similar in price with the Timber and Timber plus buildings showing only a 6% and 11% increase in total cost respectively.

Thesis (M.Soc.Sc.)--University of Hong Kong, 1984. / Also available in print.

VELHO, Liana Cleide Flor de Lima. Avaliação da Retenção de Nutrientes, Aspectos Sensoriais e Microbiológicos de Batata-Doce (Ipomoea Batatas (L.) Lam.) Submetida a Diferentes Métodos de Cocção. 2016. 109 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos)-Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2016-08-31T19:41:12Z No. of bitstreams: 1 2016_dis_lcflvelho.pdf: 3304129 bytes, checksum: 703028e8641aa28d63fb0da59e643aa1 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-08-31T23:10:40Z (GMT) No. of bitstreams: 1 2016_dis_lcflvelho.pdf: 3304129 bytes, checksum: 703028e8641aa28d63fb0da59e643aa1 (MD5) / Made available in DSpace on 2016-08-31T23:10:40Z (GMT). No. of bitstreams: 1 2016_dis_lcflvelho.pdf: 3304129 bytes, checksum: 703028e8641aa28d63fb0da59e643aa1 (MD5) Previous issue date: 2016 / The sweet potato (Ipomoea batatas (L.) Lam.) is a tuberous root plant that belongs to the Convolvulaceae family. It is one of the most important economic crops in many tropical and subtropical countries and it is the fourth most consumed vegetable in Brazil. Due to its nutritional composition, sweet potato is considered one of the healthiest foods on the planet. The sweet potato is high in energy, vitamins C and B complex, minerals, and also has phytochemical components that are beneficial to one´s health. In order to be consumed, the sweet potato must be subjected to heat for starch gelatinization to occur. However, the cooking methods cause chemical and physical changes that can modify their nutritional value. The objective of this study is to evaluate the retention of nutrients in sweet potatoes subjected to conventional cooking methods (boiling, steam, conventional oven and pressure cooker) and contemporary cooking methods (microwave and combination oven), and to evaluate the sensory acceptance and microbiological characteristics of each method. The chemical, physical-chemical, coloring, ascorbic acid, carotenoids, total polyphenols, and antioxidant activity determinations were conducted in triplicate through ABTS and FRAP assays, as well as sensory and microbiological analysis. The results were submitted to (ANOVA) variance analysis at 5% probability through the F-test and when the results were significant, they were submitted to the Tukey’s range test. The Pearson correlation coefficient (PCC) and principal component analysis (PCA) were also performed in order to correlate the results. A significant effect was found at (p ≤ 0.05) for all the treatments in the study in relation to all chemical and physico-chemical parameters of raw and cooked sweet potato samples. The sweet potato pH values showed a slight increase after processing, except for the combination oven method. The color of the cooked samples was less bright (L*), less green (negative a*) and less yellow (positive b*) than the raw sample. There was a reduction in ascorbic acid content in all the cooking methods, with less loss in samples submitted to cooking with the boiling method and in the combination oven method, which showed 9,77 ± 0,01 mg of ascorbic acid/100g in the fresh sample. Carotenoids were only detected in the boiling, oven, and microwave methods, however there was no significant difference between their means. The total polyphenol increased in all cooking methods, showing variation from 116.88 (steam) to 149.47 (oven) mg GA/100g FW (mg gallic acid/100 g fresh weight). The antioxidant activity through ABTS and FRAP assays increased in all cooking methods compared to the raw sample. Significantly high positive correlation was found between total phenolics and both the ABTS and FRAP methods, in that the cooked samples in the oven showed the highest elevation. The sensory analysis showed no significant difference between the (p > 0,05) methods for the mean test. In the CATA test, the “sweet potato flavor”, “cooked”, and “soft” characteristics were the most indicated by food tasters to characterize the samples of sweet potatoes cooked in different methods. The sample cooked in the steam method was the one that is closest to an ideal sample of the sweet potato, because it had “soft”, “homogeneous” and “baked smell” features that are required for an ideal product, according to the food tasters. / A batata-doce (Ipomoea batatas (L.) Lam.) é uma planta de raízes tuberosas pertencentes à família das convolvuláceas, sendo uma das culturas econômicas mais importantes de muitos países tropicais e subtropicais e a quarta hortaliça mais consumida no Brasil. Por sua composição nutricional é considerada um dos alimentos mais saudáveis do planeta, por ser rica em energia, vitaminas C e do complexo B, minerais, além de possuir componentes fitoquímicos benéficos à saúde. Para ser consumida deve sofrer ação do calor para que haja a gelatinização do amido. Contudo, os métodos de cocção provocam alterações químicas e físicas que podem modificar seu valor nutricional. O objetivo do estudo foi avaliar a retenção de nutrientes em batatas-doces submetidas a métodos de cocção convencionais (ebulição, vapor, forno convencional e panela de pressão) e contemporâneos (forno de micro-ondas e a vácuo no forno combinado), além de avaliar a aceitação sensorial e as características microbiológicas de cada método. Foram conduzidas em triplicata as determinações químicas, físico-químicas, coloração, ácido ascórbico, carotenoides, polifenóis totais e atividade antioxidante pelos ensaios ABTS e FRAP, bem como avaliação sensorial e análises microbiológicas. Os resultados foram submetidos à análise de variância (ANOVA) a 5% de probabilidade pelo teste F e quando significativos foram submetidos ao teste de médias (Tukey). Também foi realizado o teste de correlação de Pearson e análise de componentes principais (ACP) a fim de correlacionar os resultados. Constatou-se efeito significativo (p ≤ 0,05) em todos os tratamentos em estudo, sobre todos os parâmetros químicos e físico-químicos das amostras de batata-doce in natura e cozidas. Os valores de pH da batata-doce apresentaram aumento após o processamento, com exceção do método à vácuo no forno combinado. A cor das amostras cozidas foi menos brilhante (L*), verde (a* negativo) e amarela (b* positivo) que a amostra in natura. Houve redução no conteúdo de ácido ascórbico em todos os métodos de cocção, havendo menor perda nas amostras submetidas à cocção em ebulição e a vácuo no forno combinado, que apresentaram 9,77 ± 0,01 mg de ácido ascórbico/100g de amostra fresca. Apenas nas amostras submetidas às cocções por ebulição, forno e micro-ondas, os carotenoides foram detectados, porém, sem diferença significativa entre suas médias. Os polifenóis totais aumentaram em todos os métodos de cocção, mostrando variação de 116,88 (vapor) a 149,47 (forno) mg ácido gálico/100g peso fresco. A atividade antioxidante pelos ensaios ABTS e FRAP aumentou em todos os métodos de cocção comparados com a amostra in natura, sendo que as amostras cozidas em forno foram as que apresentaram maior elevação. Foi verificada correlação positiva de Pearson altamente significativa entre os compostos fenólicos totais e os métodos ABTS e FRAP. Na avaliação sensorial não houve diferença significativa entre os métodos (p > 0,05) pelo teste de médias. No teste CATA, as características “sabor de batata-doce”, “cozida” e “mole” foram as mais assinaladas pelos provadores para caracterizar as amostras de batatas-doces cozidas pelos diferentes métodos. A amostra de vapor foi a que mais se aproximou de uma amostra ideal de batata-doce, pois apresentou-se “mole”, "homogênea” e com “aroma de cozido”, características necessárias à um produto ideal, segundo os provadores.