Tensile strain hardening of a metakaolin based fibre reinforced composite

Portland cement concrete is the most used building material in the world. However, its manufacture is energy-intensive and it is susceptible to harsh environments. Alternative binder systems without ordinary Portland cement, such as geopolymers or alkali-activated materials, are recently new in the Civil Engineered world. These alternative binder systems seek, among other characteristics, improved durability and environmental efficiency. The attaining of strain hardening and multiple cracking typical of Strain Hardening Cementitious Composites (SHCC) using these alternative binder systems is very attractive from a conceptual point of view, since additional endurance to certain harsh or extreme environments, as well as enhanced durability, are usually expected as two of the main outcomes. In the present work, the behaviour of two different composites was studied: an existing Engineered Cementitious Composite (ECC) and a new composite based on an alternative binder prepared with metakaolin. Polyvinyl alcohol (PVA) fibres were used in both materials. A series of experiments, including compressive and direct tensile testing were carried out to characterize and compare the mechanical properties of both materials. The results showed that the alternative binder composite, when subjected to uniaxial tension, developed multiple cracks at steadily increasing tensile stress and strain, which is also typical of ECCs showing strain hardening behaviour. The development of fibre reinforced geopolymer or alkali-activated materials showing strain hardening ability in tension may still be considered as a novel research topic, with great potential for creating new and interesting developments for Civil Engineering and structural applications, particularly the ones subjected to harsh environments

Quality and safety conditions of flocked oats (Avena sativa L.) stored in bags: Poster

Oats (Avena sativa L.) have reached the healthy food market worldwide due to its special nutrients composition and fiber high quality. Therefore, quality & safety control is a must, both during the storage and commercialization stages. The current study evaluated the physicochemical characteristics (flakes size/variation %, pH, moisture content-mc, water activity-aw), living organisms (insects & mites / mycoflora - fungi load& genera identification), mycotoxins(ochratoxin A – OTA / zearalenone – ZON / aflatoxins – AFLs / esterigmatocistin – EST)andthe storage conditions of flocked oats stored inbags.Regarding the oats physicochemical characteristics, flakes particle size varied, however most of the samples present size uniformityand only one sample had high percentage of residue. That indicates high insects and other living organisms activity (consumption / proliferation) of oats starch and other nutrients. The analysis through stereomicroscope showed intense presence of insects and mites. Samples were seen also sheltering those living organisms (27%), which are not allowed by regulation (no soils, parasites and larvae presence). As expected, mc (10.8-13.2%) and/or aw (0.61-0.90) varied, however they kept on the safer levels (< 13% / 0.90) insects/mites and fungi growth wise. With respect to pH, it varied from4.1to 5.85, indicating some rancidity/fermentation reactions taking place, thus changes in organoleptic parameters. The total fungi load ranged from 3x102 to 1.29x105 CFU/g, with Aspergillus and Rhizopusthe genera more identified. Only one sample was toxin contaminated (OTA - 80 µg/kg). Insects are known vectors of fungal spores and can spread their hyphae on their dead/live skeleton, apart from mites that can trigger allergies in humans and animals. Therefore, current data demonstrate that despite the storage conditions control application, living organisms can occur in flocked oats (stored in bags) and it is necessary to apply decontamination methods to control/prevent their proliferation.Oats (Avena sativa L.) have reached the healthy food market worldwide due to its special nutrients composition and fiber high quality. Therefore, quality & safety control is a must, both during the storage and commercialization stages. The current study evaluated the physicochemical characteristics (flakes size/variation %, pH, moisture content-mc, water activity-aw), living organisms (insects & mites / mycoflora - fungi load& genera identification), mycotoxins(ochratoxin A – OTA / zearalenone – ZON / aflatoxins – AFLs / esterigmatocistin – EST)andthe storage conditions of flocked oats stored inbags.Regarding the oats physicochemical characteristics, flakes particle size varied, however most of the samples present size uniformityand only one sample had high percentage of residue. That indicates high insects and other living organisms activity (consumption / proliferation) of oats starch and other nutrients. The analysis through stereomicroscope showed intense presence of insects and mites. Samples were seen also sheltering those living organisms (27%), which are not allowed by regulation (no soils, parasites and larvae presence). As expected, mc (10.8-13.2%) and/or aw (0.61-0.90) varied, however they kept on the safer levels (< 13% / 0.90) insects/mites and fungi growth wise. With respect to pH, it varied from4.1to 5.85, indicating some rancidity/fermentation reactions taking place, thus changes in organoleptic parameters. The total fungi load ranged from 3x102 to 1.29x105 CFU/g, with Aspergillus and Rhizopusthe genera more identified. Only one sample was toxin contaminated (OTA - 80 µg/kg). Insects are known vectors of fungal spores and can spread their hyphae on their dead/live skeleton, apart from mites that can trigger allergies in humans and animals. Therefore, current data demonstrate that despite the storage conditions control application, living organisms can occur in flocked oats (stored in bags) and it is necessary to apply decontamination methods to control/prevent their proliferation

Evaluation of the indicators of inflammation in the diagnosis of ovine mastitis

O objetivo do presente trabalho foi avaliar diferentes indicadores inflamatórios no diagnóstico da mamite em ovinos da raça Santa Inês. Após a realização do exame físico das mamas e a prova de fundo escuro, foram coletadas e analisadas 390 amostras de leite, sendo as metades mamárias divididas de acordo com o exame bacteriológico e a prova de fundo escuro, resultando em 290 amostras negativas em ambos os exames, 90 amostras negativas à prova de fundo escuro e positivas na cultura bacteriológica, 5 amostras positivas à prova de fundo escuro e negativas ao exame bacteriológico e 3 amostras positivas em ambos os testes. Nestas amostras foram realizadas a contagem automática de células somáticas (CCS), o California Mastitis Test (CMT), a determinação da concentração hidrogeniônica (pH) e dos teores de cloreto e lactose, e ainda a avaliação do índice de cloreto-lactose. Os maiores valores preditivos foram observados para a CCS, CMT e teor de cloreto; o pH, o teor de lactose e o índice cloreto-lactose apresentaram-se como marcadores inflamatórios menos sensíveis, onde se considerou o resultado da cultura bacteriológica como padrão ouro. O exame físico não se mostrou como método diagnóstico seguro quando utilizado isoladamente, exaltando a importância da associação de outros meios diagnósticos indiretosThe aim of this trial was to evaluate distinct indictors of inflammation in the diagnosis of mastitis in Santa Ines ewes. The physical examination and the dark bottom cup test were performed. Afterwards, the bacteriologic samples of 390 milk samples were analyzed. The samples were divided according to the bacteriological examination and the dark cup bottom test, resulting in 290 samples negative in both tests, 90 samples positive in the bacteriological examination and negative in the dark cup bottom test, 5 samples positive in the dark cup bottom test and negative in bacteriological culture, and 3 samples positive in both tests. The automatic somatic cell count (SSC), the California mastitis test (CMT), the pH, the chloride and lactose content, and the chloride-lactose number were established. Then, their predictive value as a indicator of inflammation was calculated assuming the bacteriologic examination as the gold standard test. The CCS, CMT and chloride content proved to be the best predictors, while the pH, the lactose content and chloride-lactose number were the least sensitive tests. The physical examination was revealed to be a nonsensitive diagnostic procedure when used as the only procedure to detect the disease, showing that other diagnostics tests are requiredFAPESPCNP

Two-dimensional and three-dimensional techniques for determining the kinematic patterns for hindlimb obstacle avoidance during sheep locomotion

ABSTRACT: Analysis of locomotion is often used as a measure for impairment and recovery following experimental peripheral nerve injury. Compared to rodents, sheep offer several advantages for studying peripheral nerve regeneration. In the present study, we compared for the first time, two-dimensional (2D) and three-dimensional (3D) hindlimb kinematics during obstacle avoidance in the ovine model. This study obtained kinematic data to serve as a template for an objective assessment of the ankle joint motion in future studies of common peroneal nerve (CP) injury and repair in the ovine model. The strategy used by the sheep to bring the hindlimb over a moderately high obstacle, set to 10% of its hindlimb length, was pronounced knee, ankle and metatarsophalangeal flexion when approaching and clearing the obstacle. Despite the overall time course kinematic patterns about the hip, knee, ankle, and metatarsophalangeal were identical, we found significant differences between values of the 2D and 3D joint angular motion. Our results showed that the most apparent changes that occurred during the gait cycle were for the ankle (2D-measured STANCEmax: 157±2.4 degrees vs. 3D-measured STANCEmax: 151±1.2 degrees; P<.05) and metatarsophalangeal joints (2D-measured STANCEmin: 151±2.2 degrees vs. 3D-measured STANCEmin: 162 ± 2.2 degrees; P<.01 and 2D-measured TO: 163±4.9 degrees vs. 3D-measured TO: 177±1.4 degrees; P<.05), whereas the hip and knee joints were much less affected. Data and techniques described here are useful for an objective assessment of altered gait after CP injury and repairin an ovine model