Search results for "Shaker"
showing 10 items of 10 documents
Vibration Monitoring of the Mechanical Harvesting of Citrus to Improve Fruit Detachment Efficiency
2019
The introduction of a mechanical harvesting process for oranges can contribute to enhancing farm profitability and reducing labour dependency. The objective of this work is to determine the spread of the vibration in citrus tree canopies to establish recommendations to reach high values of fruit detachment efficiency and eliminate the need for subsequent hand-harvesting processes. Field tests were carried out with a lateral tractor-drawn canopy shaker on four commercial plots of sweet oranges. Canopy vibration during the harvesting process was measured with a set of triaxial accelerometer sensors with a datalogger placed on 90 bearing branches. Monitoring of the vibration process, fruit pro…
Frequency-domain experimental setup for mechatronic and suspension system components
2021
This paper presents a frequency-domain experimental setup for modal analysis of mechatronic and suspension system components. Design, instrumentation and dynamic behavior of the one degree-of-freedom (DOF) system, capable of providing both, periodic and application-specific, excitation forces is described. The excitation is realized by an electromagnetic modal shaker with additional assembly and interface components designed and instrumented for frequency -domain analysis of vertical dynamics. Frequency response functions (FRFs) of the implemented system are experimentally measured and the associated basic model parameters are calculated, correspondingly identified. Accurate fit between the…
Differential localization of voltage-gated potassium channels duringDrosophilametamorphosis
2020
Neuronal excitability is determined by the combination of different ion channels and their sub-neuronal localization. This study utilizes protein trap fly strains with endogenously tagged channels ...
Optimising the efficiency of olive harvesting considering operator safety
2019
Mechanical-assisted harvesting of olives, which is carried out using hand-held harvesting units that detach the drupes through vibration supplied by electric motor or combustion engines, is a widespread method used in southern Italy. Such machines are able to harvest more than 80% of the overall quantity of olives available per tree in 5–10 min, but their performance is influenced by several factors related to the mechanical characteristics of the device and to the features of the trees. Here the problem of optimising harvesting efficiency whilst minimising the health risks to the operators is investigated, with the aim of demonstrating that it is possible to determine an optimum harvesting…
Postnatal increases in axonal conduction velocity of an identified Drosophila interneuron require fast sodium, L-type calcium and shaker potassium ch…
2019
Abstract During early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in the Drosophila giant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelina…
Role of K+ and Ca2+ fluxes in the cerebroarterial vasoactive effects of sildenafil
2007
The aim of this study was to assess the role of K(+) and Ca(2+) fluxes in the cerebroarterial vasoactive effects of the phosphodiesterase-5 inhibitor sildenafil. We used isolated rabbit basilar arteries to assess the effects of extracellular K(+) raising on sildenafil-induced vasodilatation, and studied the pharmacological interaction of sildenafil with selective modulators of membrane K(+) and Ca(2+) channels. Expression of Kv1 subunits of K(+) channels was assessed at messenger and protein levels. Parallel experiments were carried out with zaprinast for comparison. Sildenafil (10 nM-0.1 mM) induced concentration-dependent relaxation of endothelin-1 (10 nM)-precontracted arteries, which wa…
Two Structurally Distinct Pathways for the Voltage-Sensing S4 Helices
2010
In voltage-dependent ion channels, the movement of the voltage-sensing S4 helices produces gating currents. The charge displaced as a function of the membrane potential (Q-V) is well described by a sequential two-state Boltzmann relation, indicating that there are at least two steps of gating charge movement from their Resting state to the Active state. In addition, it has been shown that at a maintained positive potential, the S4 helices of voltage-gated Na, Ca and K channels and the voltage sensitive phosphatase Ci-VSP, undergo a slower secondary conformational transition stabilizing the sensor in a Relaxed (inactivated) state. From the Relaxed state, the Q-V relation exhibits a strong sh…
A System to Simplify the Use of Mounted Shakers for Harvesting Olives and Dry Fruits
2009
The shakers for harvesting olives and dry fruits have reached a high standard and their use is increasing rapidly. In order to satisfy the different demand, manufacturers offer a wide range of shakers, from the more expensive self-propelled ones to those to be mounted on the tractor’s power lift, with shaking headers of different mass and size, suitable for the different orchard characteristics. Self-propelled shakers have high steering capacity and optimum visual field for the operator, so their working capacity is very high with respect to that of mounted shakers, which are less expensive but have lower steering capacity and a limited view on the header. Therefore the approaching of mount…
Evaluation of different mechanical fruit harvesting systems and oil quality in very large size olive trees
2014
In 2006 and 2009, trials were carried out in the Apulia region in Southern Italy to evalu-ate the possibility of mechanizing olive harvesting in groves of old and very large trees. The trees belonged to the cultivars ‘Cellina di Nardò’ and ‘Ogliarola Salentina’. They were 60-100 years old and 7-9 m tall with a canopy volume of 140-360 m3. In the first half of November 2006, with a mechanical beater mounted on a tractor plus hand-held pneumatic combs, the harvesting yield was close to 90% of the total olives present in the canopy, and the harvesting working productivity was around 60 kg of harvested olives h-1 worker-1. With a self-propelled shaker attached to the main branches the harvestin…