87 research outputs found

    Safety assessment of underground vehicles passing over highly resilient curved tracks in the presence of a broken rail

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    Vehicle–track interaction for a new resilient slab track designed to reduce noise and vibration levels was analysed, in order to assess the derailment risk on a curved track when encountering a broken rail. Sensitivity of the rail support spacing of the relative position of the rail breakage between two adjacent rail supports and of running speed were analysed for two different elasticities of the rail fastening system. In none of the cases analysed was observed an appreciable difference between either of the elastic systems. As was expected, the most unfavourable situations were those with greater rail support spacing and those with greater distance from the breakage to the nearest rail support, although in none of the simulations performed did a derailment occur when running over the broken rail. When varying the running speed, the most favourable condition was obtained for an intermediate speed, due to the superposition of two antagonistic effects

    Effect of late weaning and use of alternative cages on performance of does, suckling and fattening rabbits under extensive reproductive management

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    The effects of the combined use of long lactation periods (46 days) with alternative cages on the reproductive and growth performance of 104 rabbit does and their litters during five consecutive reproductive cycles were studied. Half of does were housed in conventional polyvalent cages (39 cm×100 cm×30 cm) and the other half in alternative polyvalent cages (39 cm×100 cm×60 cm), with a raised platform. Half of the rabbit does in each type of cage were weaned at 32 and the other half at 46 days after parturition. Longer lactation negatively affected the body weight (P<0.001), fat and energy content (P<0.05) of rabbit does at the end of the lactation period, but this effect decreased with the number of parturitions. Fertility, prolificacy and doe mortality were not affected by lactation length. Late weaning led to higher litter size (by 8.9%) and litter weight (by 11.3%) at the end of growing period (P<0.001) and lower feed conversion ratio per cage during the experimental period (13.5%) than weaning at 32 day (P<0.001). These results were paralleled by lower mortality (12.6 vs. 17.6%; P<0.01) of young rabbits weaned later during the overall experimental period. Differences in performance as a result of different weaning ages were only observed during cycles with worst health status (third and fifth cycles) in which late weaning decreased mortality. Type of cage did not affect doe body weight and body condition, mortality, fertility, prolificacy and litter size during the five reproductive cycles. Nevertheless, at day 21 litter weight and feed conversion ratio between 3 and 21 day were 4.2% higher (P<0.01) and 5.0% lower (P<0.05), respectively, in animals housed in alternative rather than in conventional cages. Alternative cages also led to heavier litters at 59 days (P<0.01). It was concluded that the combined use of longer lactations and cages with higher available surface with a raised platform could be alternatives to improve animal welfare in farmed rabbit

    Percepção dos consumidores relativamente à carne de bovino: critérios de escolha a partir de grupos de discussão

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    Nas economias desenvolvidas, a segurança dos alimentos, o bem‑estar animal e o ambiente tĂȘm vindo a assumir relevĂąncia nas preocupaçÔes dos consumidores. ProcurĂĄmos saber, atravĂ©s da metodologia dos grupos de discussĂŁo (focus groups) realizados em duas cidades de Portugal, Lisboa e Porto, as preocupaçÔes e perceçÔes dos consumidores relativamente a estes atributos, os quais sĂŁo essencialmente acreditados. Este conhecimento Ă© fundamental para a aplicação posterior de mĂ©todos de preferĂȘncias declaradas. Foi ainda possĂ­vel obter, com base em exercĂ­cios de seleção entre carnes diferenciadas, e atravĂ©s de um modelo logit, intervalos de preços passĂ­veis de serem utilizados posteriormente na definição de cenĂĄrios em experiĂȘncias de escolha (mĂ©todo de preferĂȘncias declaradas) -----ABSTRACT-----In developed economies, food safety, animal welfare and the environment have become relevant consumers’ concerns. We conducted several focus groups in two Portuguese cities, Lisboa and Porto, in order to get participants perceptions and concerns for these attributes, which are essentially credence attributes. This knowledge is critical for the subsequent application of stated preference methods. It was also possible to estimate, based on exercises of selection among different meats, and through a logit model, price ranges that could be used in the definition of scenarios for choice experiments (stated preference method)info:eu-repo/semantics/publishedVersio

    Does corporate reputation matter? Role of social media in consumer intention to purchase innovative food product

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    The exponential growth of the corporate reputation in food industry has resulted in innovations in every link of its supply chain. There have been studies that have characterized innovation in various industries from the perspective of technology, but far fewer in the area of corporate reputation, consumer perception, and intention towards innovations in food products. This research analyses the innovations in the food industry from the perspective of the consumer and provides a conceptual framework of food innovation stages. The study also investigates the relationship between corporate reputation and intention towards food innovation along with the other components of TPB model with an extension of social media engagement. The results from India and US samples confirm that social media engagement have a significant role to play in creating intention to purchase innovative food products. The study compares the US and Indian samples and identifies differences in subjective norms and perceived behavioural control

    Noise reduction in urban LRT networks by combining track based solutions

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    The overall objective of the Quiet-Track project is to provide step-changing track based noise mitigation and maintenance schemes for railway rolling noise in LRT (Light Rail Transit) networks. WP 4 in particular focuses on the combination of existing track based solutions to yield a global performance of at least 6 dB(A). The validation was carried out using a track section in the network of Athens Metro Line 1 with an existing outside concrete slab track (RHEDA track) where high airborne rolling noise was observed. The procedure for the selection of mitigation measures is based on numerical simulations, combining WRNOISE and IMMI software tools for noise prediction with experimental determination of the required track and vehicle parameters (e.g., rail and wheel roughness). The availability of a detailed rolling noise calculation procedure allows for detailed designing of measures and of ranking individual measures. It achieves this by including the modelling of the wheel/rail source intensity and of the noise propagation with the ability to evaluate the effect of modifications at source level (e.g., grinding, rail dampers, wheel dampers, change in resiliency of wheels and/or rail fixation) and of modifications in the propagation path (absorption at the track base, noise barriers, screening). A relevant combination of existing solutions was selected in the function of the simulation results. Three distinct existing solutions were designed in detail aiming at a high rolling noise attenuation and not affecting the normal operation of the metro system: Action 1: implementation of sound absorbing precast elements (panel type) on the track bed, Action 2: implementation of an absorbing noise barrier with a height of 1.10–1.20 m above rail level, and Action 3: installation of rail dampers. The selected solutions were implemented on site and the global performance was measured step by step for comparison with simulations. © 2015 Elsevier B.V

    High railway rolling noise reduction by combining existing track based solutions

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    The overall objective of the EU funded Quiet-Track project is to provide step changing track based noise mitigation systems and maintenance schemes for the railway rolling noise. This paper focuses on the combination of existing track based solutions to yield a global performance of at least 6 dB(A). The analysis and validation was carried out considering a track section in the network of Attiko Metro line 1 with an existing outside concrete slab track (RHEDA track) where high airborne rolling noise was observed. The procedure for the selection of mitigation measures is based on numerical simulations, combining two software tools for noise prediction, WRNOISE and IMMI with experimental determination of the required track and vehicle parameters. The availability of a detailed rolling noise calculation procedure, which includes the modelling of the wheel/rail source intensity and of the noise propagation with ability to evaluate the effect of modifications at source level (e.g. grinding, rail dampers, wheel dampers, change in resiliency of wheels and/or rail fixation) and of modifications in the propagation path (absorption at the track base, noise barriers, screening) allows for detailed designing of measures and of ranking individual measures. A relevant combination of existing solutions was selected in function of the simulation results. Three distinct existing solutions were designed in detail aiming at a high rolling noise attenuation and not affecting the normal operation of the metro system: - Action 1: implementation of sound absorbing precast elements (panel type) horizontally distributed in the track bed; - Action 2: Implementation of an absorbing noise barrier with a height of 1.10-1.20 m above rail level and close to the track and vehicle; - Action 3: Installation of rail dampers at the selected track. The selected solutions were implemented on-site and the global performance was measured-step by step-for comparison with simulations. A very good agreement was found between simulations and measurements after installation and a global noise attenuation performance of 9 dB(A) was obtained at the considered receiver location.
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