86,801 research outputs found
Effect of Finnsheep crossbreeding on Lamon sheep performance: in vivo traits
No full textThe objective of this trial was the comparison of the in vivo traits of Lamon (L), a local meat breed of the Eastern Italia Alps, and Finnsheep X Lamon (F x L) fattening lambs. Forty-one lambs (25 L and 16 F x L) of both sexes were weaned at 8 weeks of age and fattened for 14 weeks. The diet (11,6 MJ/kg d.m.M.E.) consisted of maize silage ad lib., 200 g/d of dried sugar beet pulp, 150 g/d of soybean meal and 30 g/d supplement. F x L lambs grew slightly more than L lambs (197 vs 176 g/d; P .1) while M.E. requirements for growth, estimated assuming a maintenance requirement of.44 MJ • d-1 • kg-1 • L.W.-75, resulted higher (+7 %) for F x L than for L lambs (2.18 vs 2.04 MJ • kgDG • kg-1 • L.W.-75; P < .1). The ram-lambs showed superior growth potential and feed efficiency in respect to the ewe-lambs. In conclusion it appears that crossbreeding with Finnsheep is not detrimental to the in vivo performance of fattening Lamon lambs except for a slight increase of the energy requirements for growth
EFFECT OF FINNSHEEP CROSSBREEDING ON LAMON SHEEP PERFORMANCE - POST-MORTEM TRAITS
No full textThis experiment was conducted in order to study the effects of crossbreeding of the local breed Lamon (L) with Finnsheep (F),on the post-mortem performance of F, lambs (F x L). Nine L and 8 F x L ram-lambs were fattened with a diet (11.6 MJ M.E./kg d.m.) based on maize silage, dried sugar beet pulp and soybean meal, and slaughtered at 40.5 ± 5.9 kg live weight at the age of 22 weeks. Genotype did not affect dressing percentage on empty body weight (E.B.W.) but the crossbred lambs showed a lower incidence of the pelt (18,4 vs 20.2 % on E.B.W.;
Analysis of multiple crack initiation and propagation in glass/epoxy woven fabrics under cyclic loadings
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Considerazioni sulla propagazione a fatica di cricche trasversali in laminati compositi: confronto tra cross-ply e DCB
No full textSviluppo e validazione di un modello analitico per la previsione delle proprietà elastiche e delle tensioni locali in compositi tessuti
No full textA multiscale strategy for assessing the micro-scale stress distribution in the matrix of textile composites
No full textIn this work, a multiscale strategy for estimating the local stress fields in the matrix of woven composites is presented. This is a fundamental tool for predicting the static and fatigue bundle crack initiation. The strategy adopts first an analytical model to estimate the average stresses in the bundles at the meso-scale. These are used as an input for 2D Finite Element (FE) analyses on representative volume elements to calculate the local stress fields in the matrix at the micro-scale. In particular, the cumulative distribution function of the local stress components in the matrix are predicted. From that, the average stresses in a control volume of the matrix are obtained, to be used for assessing the crack initiation in off-axis bundles. The entire strategy is validated experimentally, in terms of elastic properties, and numerically, in terms of average bundle stresses and local stress fields obtained through full 3D FE analyses
A Collaborative Robotic Approach to Autonomous Pallet Jack Transportation and Positioning
No full textThis paper proposes a novel loco-manipulation control framework for the execution of complex tasks with kinodynamic constraints using mobile manipulators. As a representative example, we consider the handling and re-positioning of pallet jacks (or lifts/carriers with similar characteristics) in unstructured environments. This task is associated with significant challenges in terms of locomotion, due to the mobility constraints that are imposed by their limited kinematics while moving, and manipulation, due to the existence of dynamic uncertainties while grasping and handling of pallet jacks. To tackle these challenges, our solution enables the robotic platform to autonomously reach a pallet jack location while avoiding the obstacles, and to detect and manipulate its handle by fusing the perception and the contact force data. Subsequently, the transportation of the pallet jack is achieved through a whole-body impedance controller and a trajectory planner which takes into account the mobility constraints of the robot-pallet jack chain. We demonstrate the effectiveness of the proposed solution in reaching and displacing the pallets to desired locations through simulation studies and experimental results. While these results reveal with a proof-of-concept the effectiveness of the proposed framework, they also demonstrate the high potential of mobile manipulators for relieving human workers from such repetitive and labor intensive tasks. We believe that this extended functionality can contribute to increasing the usability of mobile manipulators in different application scenarios
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