1,027 research outputs found

    Definition of a benchmark for low Reynolds number propeller aeroacoustics

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    Experimental and numerical results of a propeller of 0.3 m diameter operated at 5000 RPM and axial velocity ranging from 0 to 20 m/s and advance ratio ranging from 0 to 0.8 are presented as a preliminary step towards the definition of a benchmark configuration for low Reynolds number propeller aeroacoustics. The corresponding rotational tip Mach number is 0.23 and the Reynolds number based on the blade sectional chord and flow velocity varies from about 46000 to 106000 in the operational domain and in the 30% to 100% blade radial range. Force and noise measurements carried out in a low-speed semi-anechoic wind-tunnel are compared to scale-resolved CFD and low-fidelity numerical predictions. Results identify the experimental and numerical challenges of the benchmark and the relevance of fundamental research questions related to transition and other low Reynolds number effects

    Multi-language neural network language models

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    Recently there has been a lot of interest in neural network based language models. These models typically consist of vocabulary dependent input and output layers and one or more vocabulary independent hidden layers. One standard issue with these approaches is that large quantities of training data are needed to ensure robust parameter estimates. This poses a significant problem when only limited data is available. One possible way to address this issue is augmentation: model-based, in the form of language model interpolation, and data-based, in the form of data augmentation. However, these approaches may not always be possible to use due to vocabulary dependent input and output layers. This seriously restricts the nature of the data possible to use in augmentation. This paper describes a general solution whereby only one or more vocabulary independent hidden layers are augmented. Such approach makes it possible to examine augmentation from previously impossible domains. Moreover, this approach paves a direct way for multi-task learning with these models. As a proof of the concept this paper examines the use of multilingual data for augmenting hidden layers of recurrent neural network language models. Experiments are conducted using a set of language packs released within IARPA Babel program

    Towards the definition of a benchmark for low Reynolds number propeller aeroacoustics

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    Experimental and numerical results of a propeller of 0.3 m diameter operated in quiescent standard ambient conditions at 5000 RPM and axial velocity ranging from 0 to 20 m/s and advance ratio ranging from 0 to 0.8 are presented as a preliminary step towards the definition of a benchmark configuration for low Reynolds number propeller aeroacoustics. The corresponding rotational tip Mach number is 0.231 and the Reynolds number based on the blade sectional chord and flow velocity in the whole radial and operational domain ranges from about 54000 to 106000. Force and noise measurements carried out in a low-speed semi-anechoic windtunnel are compared with scale-resolved CFD and low-fidelity numerical results. Results identify the experimental and numerical challenges of the benchmark and the relevance of fundamental research questions related to transition and other low Reynolds number effects

    Sensory quality of meat from lambs fed on different diets

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    The whole seed of sweet lupin var. Multitalia with a protein content higher than 35% and a low content in alkaloids constitutes a good protein source alternative to soybean meal, today deriving for more than 60% from OGM (Genetically Modified Organisms) cultivation. Moreover, the poor national production and the cost of feeds for animals forces the livestock compartment to utilize alternative biomasses the availability of which highly depends on from the environment and the season

    Improvement of sheep welfare and milk production fed on diet containing hydroponically germinating seeds.

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    Plasma cortisol and milk production responses of 45 lactating Comisana sheeps (4th- 5th parity), divided into three homogeneous groups of 15 subject each, were used to evaluate the effects of two different levels of partial substitution of a complete feed with hydroponically germinating seeds. Germinated oat was employed after 7 days of hydroponic growth. The three groups received the following diets: Control group (T) received only complete feed. The other 2 groups were fed on diet containing different levels of hydroponically germinating oat (1,5 kg – group A; 3 kg – group B). All the subjects have shown to accept the diets because the per capita ration was always completely consumed. In the second month, the A and B groups showed lower average values of cortisol (P<0.01) and a statistically significant increase in milk production as compared to T (P<0.05 and P<0.001). The obtained data induced to conclude that integration with hydroponically germinating oat in partial substitution of the complete feed does not modify biochemical and hematological parameters and seems to produce an improvement in animal welfare and production of milk

    An amino acid mixture, enriched with Krebs cycle intermediates, enhances extracellular matrix gene expression in cultured human fibroblasts

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    : In the human body, the skin is one of the organs most affected by the aging process. Nutritional approaches aimed to counteract the age-induced decline of extracellular matrix (ECM) deposition could be a valuable tool to decrease the degenerative processes underlying skin aging. Here, we investigated the ability of a six-amino acid plus hyaluronic acid (6AAH) formulation enriched with tricarboxylic acid (TCA) intermediates to stimulate ECM gene expression. To this aim, human BJ fibroblasts were treated with 6AAH alone or plus succinate or malate alone or succinate plus malate (6AAHSM), and mRNA levels of several ECM markers were evaluated. 6AAHSM increased the expression of all the ECM markers significantly above 6AAH alone or plus only succinate or malate. Furthermore, in an in vitro oxidative damage model, 6AAHSM blunted the hydrogen peroxide-induced decline in ECM gene expression. Our data suggest that feeding cells with 6AAH enriched with TCAs could efficiently be employed as a non-pharmacological approach for counteracting skin aging

    Development of engineering design tools to help reduce apple bruising

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    A large percentage of apples are wasted each year due to damage such as bruising. The apple journey from orchard to supermarket is very complex and apples are subjected to a variety of static and dynamic loads that could result in this damage occurring. The main aim of this work was to carry out numerical modelling to develop a design tool that can be used to optimise the design of harvesting and sorting equipment and packaging media to reduce the likelihood of apple bruise formation resulting from impact loads. An experimental study, along with analytical calculations, varying apple drop heights and counterface material properties, were used to provide data to validate the numerical modelling. Good correlation was seen between the models and experiments and this approach combined with previous work on static modelling should provide a comprehensive design tool for reducing the likelihood of apple bruising occurring
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