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71.
Sixty male Apenninica suckling lambs carcasses were studied in order to evaluate the relationship between carcass and meat quality of light lambs as evaluated according to the EU Mediterranean classification system. Increased carcass weight (6–12 kg) was accompanied by greater carcass size and compactness and reduced bone percentage. Moreover the meat quality was similar with the increase of carcass weight in terms of colour, water holding capacity and suitability for domestic storage. No differences for the examined parameters were found between carcasses classified in quality 1 and 2. The EU Mediterranean classification system appears to be unrelated to the quality of the merchandized meat.  相似文献   
72.
Human-robot synchrony: flexible assistance using adaptive oscillators   总被引:1,自引:0,他引:1  
We propose a novel method for movement assistance that is based on adaptive oscillators, i.e., mathematical tools that are capable of extracting the high-level features (amplitude, frequency, and offset) of a periodic signal. Such an oscillator acts like a filter on these features, but keeps its output in phase with respect to the input signal. Using a simple inverse model, we predicted the torque produced by human participants during rhythmic flexion-extension of the elbow. Feeding back a fraction of this estimated torque to the participant through an elbow exoskeleton, we were able to prove the assistance efficiency through a marked decrease of the biceps and triceps electromyography. Importantly, since the oscillator adapted to the movement imposed by the user, the method flexibly allowed us to change the movement pattern and was still efficient during the nonstationary epochs. This method holds promise for the development of new robot-assisted rehabilitation protocols because it does not require prespecifying a reference trajectory and does not require complex signal sensing or single-user calibration: the only signal that is measured is the position of the augmented joint. In this paper, we further demonstrate that this assistance was very intuitive for the participants who adapted almost instantaneously.  相似文献   
73.
74.
A simple method for parametric analysis of grid amplifier performances is presented here. The proposed approach is based on the development of an equivalent transmission line model where each element of the grid is represented by an S-matrix derived from a full-wave simulation in an infinite array environment. The proposed technique makes it possible to investigate the dependency of grid amplifier performance on its major parameters taking into account the actual geometry of each part of the circuit while preserving the simulation efficiency.  相似文献   
75.
The problem of information flow in multithreaded programs remains an important open challenge. Existing approaches to specifying and enforcing information-flow security often suffer from over-restrictiveness, relying on nonstandard semantics, lack of compositionality, inability to handle dynamic threads, inability to handle synchronization, scheduler dependence, and efficiency overhead for the code that results from security-enforcing transformations. This paper suggests a remedy for some of these shortcomings by developing a novel treatment of the interaction between threads and the scheduler. As a result, we present a permissive noninterference-like security specification and a compositional security type system that provably enforces this specification. The type system guarantees security for a wide class of schedulers and provides a flexible and efficiency-friendly treatment of dynamic threads.  相似文献   
76.
First results from a study on tunable frequency-selective surfaces (FSSs) used for beam-steering applications are reported. In particular, the scattering response of a multilayer passband FSS based on varactorloaded rectangular slots has been investigated. Simulated and measured results show that tunable FSSs can be employed to locally control the phase of the transmitted field with limited amplitude losses.  相似文献   
77.
A research program addressed to evaluate the magnesium hydride storage scaling up effects is being developed by CESI RICERCA, Milano, and the Hydrogen Group of Padova University. A storage device containing 500 g of magnesium hydride powder (manufactured by Venezia Tecnologie S.p.A. using high-energy ball milling) has been designed and tested in different operating conditions. A number of absorption and desorption cycles at different temperatures and pressures has been carried out in order to see if the results are comparable with laboratory data obtained on small amounts (fractions of grams) of powder samples. A sensible performance degradation that reduced the overall storage capacity of about 50% has been noticed after 20 cycles, presumably due to local powder heating, fragmentation and subsequent compaction. Further tests on a smaller tank equipped also with a porous baffle gave useful indications for the design of an improved large hydrogen reservoir.  相似文献   
78.
The scope for diffusion of very low-enthalpy geothermal plants in the Piemonte region of Italy, using groundwater heat pumps (GWHP), was analyzed to check environmental sustainability and the benefits in terms of reducing greenhouse gas emissions from fossil fuels. GWHP implementation seemed particularly suitable to the specific characteristics of the Piemonte plain. An important thick and productive shallow aquifer is present across the entire plain beneath the major energy users and is therefore appropriate for geothermal energy development purposes. The building stock could be adapted to heat pumps in different ways, but objective-oriented policies will be required to reach the best results in terms of environmental benefits.  相似文献   
79.
Consumers are oriented towards fresh-cut vegetables that provide phytonutrients useful for preventing stress-related diseases. The aim of this work was to evaluate the cut operations on the quality changes of lamb's lettuce ( Valerianella olitoria L.) cv. Trofy during storage at 4 °C for 8 days. Results showed that chlorophyll and carotenoids reduction was observed after 8 days of storage. In both treatments, total carotenoids after 8 days decreased from 20 to 16 mg g−1 FW. Free and total phenols increased with storage in both treatments. Total phenols were 23% higher in control (32 μmol g−1 FW) compared to cut leaves (25 μmol g−1 FW) after 8 days of storage. Anthocyanins increased after 8 days and reached 30 mg 100 g−1 FW without significant difference between treatments. Ascorbic acid (AsA) and dehydroascorbic (DHA) acid increased in cut leaves compared to control. After 1 day AsA concentration was 3 300 nmol g−1 FW in cut leaves, while in control leaves was 1 500 nmol g−1 FW. Analogously AsA + DHA was higher in cut leaves, 4 100 nmol g−1 FW, while in control leaves the mean was 3 000 nmol g−1 FW. After 5 days of storage the values of AsA returned to initial values, while AsA + DHA were lower.  相似文献   
80.
The presence of sulphur containing compounds, naturally occurring in natural gas or added as odorants, can adversely affect the performance of noble metals based catalysts for the partial oxidation of methane to syngas. In this paper the effect of SO2 addition on the catalytic partial oxidation of methane was investigated on Rh (1 wt.%) catalysts prepared by incipient wetness impregnation method on two different commercially available high temperature γ-alumina supports stabilized either with 10% SiO2 or 3% La2O3. Based on the results of catalytic activity measurements and in-situ FT-IR spectroscopic characterisation, as well as TPR/TPD studies, it has been shown that the presence of sulphur can severely suppress the formation of synthesis gas by inhibiting the reforming reactions during the catalytic partial oxidation of methane. The results also demonstrated that the support plays a crucial role in the partial oxidation reaction. In the presence of a sulphating support such as La2O3–Al2O3 the partial oxidation reaction was much less inhibited than a less sulphating support such as SiO2–Al2O3. The sulphating support acts as a sulphur storage reservoir, which minimises the poison from adsorbing on or near the active Rh sites where reactions take place.  相似文献   
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