1,404 research outputs found
Single-Particle Self-Excited Oscillator
Electronic feedback is used to self-excite the axial oscillation of a single electron in a Penning trap. Large, stable, easily detected oscillations arise even in an anharmonic potential. Amplitudes are controlled by adjusting the feedback gain, and frequencies can be made nearly independent of amplitude fluctuations. Quantum jump spectroscopy of a perpendicular cyclotron motion reveals the absolute temperature and amplitude of the self-excited oscillation. The possibility to quickly measure parts per billion frequency shifts could open the way to improved measurements of e-, e+, p, and [overline p] magnetic moments
Gambling Disorders Among Young Women Regular Gamblers: The Unique and Common Contribution of Executive Thinking Style and Mindfulness
The aim of this study is to investigate the role played by mindfulness in the relationship between cognitive styles and gambling disorders in a sample of female young adults. Participants in this study (125 women; Mage = 18.64 years; SD = 1.7) were recruited in betting or bingo halls. They completed the South Oaks Gambling Screen, the Child and Adolescent Mindfulness Measure, and Sternberg's questionnaire on thinking styles. The results from the mediation analyses revealed that the executive thinking style increases gambling and that the deficit in mindfulness ability mediates this relationship. Theoretical and clinical implications are discussed
Process parameters effect on mechanical properties and fatigue behaviour of friction stir weld AA6060 joints
Friction stir welding (FSW) is the most remarkable welding technology that has been invented and developed in the last decade. It is a solid-state welding process in which a rotating tool is driven into the material and translated along the interface of two or more plates. This technology has been successfully used to join materials that are considered difficult to be welded by fusion welding methods. FSW has potentially significant applications in many industrial fields such as aerospace, automotive, and naval industry. Anyway, FSW technology requires a meticulous understanding of the process and consequent mechanical properties of the welds in order to be used in the production of high performance components. The present work deals with an experimental campaign aimed at the evaluation of the mechanical properties of AA6060 T6 friction stir welded joints. The butt joints obtained using two different tool geometries (standard and threaded) were performed by varying the welding parameters, namely, tool rotating speed and feed rate. The standard tool was a very simple device fabricated using AISI 1040 steel, with a flat shoulder and a cylindrical pin. The threaded tool was a more complex device based on two main components: a tool holder, with a flat shoulder, and a threaded probe obtained using a commercial thread forming tap. The quality of the joints was evaluated in terms of both tensile strength (UTS) and fatigue behavior. The study of axial pulsing fatigue properties required the fabrication of a specific testing device able to avoid parasite bending moments. In order to estimate the more efficient and effective tool type, the welding forces (axial and longitudinal) were also measured
RESCUE MANAGEMENT AND ASSESSMENT OF STRUCTURAL DAMAGE BY UAV IN POST-SEISMIC EMERGENCY
Abstract. The increasing frequency of emergencies urges the need for a detailed and thorough knowledge of the landscape. The first hours after a disaster are not only chaotic and problematic, but also decisive to successfully save lives and reduce damage to the building stock. One of the most important factors in any emergency response is to get an adequate awareness of the real situation, what is only possible after a thorough analysis of all the available information obtained through the Italian protocol Topography Applied to Rescue. To this purpose geomatic tools are perfectly suited to create, manage and dynamically enrich an organized archive of data to have a quick and functional access to information useful for several types of analysis, helping to develop solutions to manage the emergency and improving the success of rescue operations. Moreover, during an emergency like an earthquake, the conventional inspection to assess the damage status of buildings requires special tools and a lot of time. Therefore, given the large number of buildings requiring safety measures and rehabilitation, efficient use of limited resources such as time and equipment, as well as the safety of the involved personnel are important aspects. The applications shown in the paper are intended to underline how the above-mentioned objective, in particular the rehabilitation interventions of the built heritage, can be achieved through the use of data acquired from UAV platform integrated with geographic data stored in GIS platforms
Assessing influence factors on daily ammonia and greenhouse gas concentrations from an open-sided cubicle barn in hot mediterranean climate
Measurement of gas concentrations constitutes basic knowledge for the computation of emissions from livestock buildings. Although it is well known that hot climate conditions increase gas emissions, in the literature the relation between gas concentrations from open barns and animalrelated parameters has not been investigated yet. This study aimed at filling this gap by evaluating daily gas concentrations within an open-sided barn in hot Mediterranean climate. The influence of microclimatic parameters (MC) and cow behavior and barn management (CBBM) were evaluated for ammonia (NH3 ), methane (CH4 ), and carbon dioxide (CO2 ) concentrations. Results showed that both MC and CBBM affected concentrations of NH3 (p < 0.02), CH4 (p < 0.001), and CO2 (p < 0.001). Higher values of NH3 concentration were detected during the cleaning of the floor by a tractor with scraper, whereas the lowest NH3 concentrations were recorded during animal lying behavior. Measured values of CO2 and CH4 were highly correlated (C = 0.87–0.89) due to the same sources of production (i.e., digestion and respiration). The different management of the cooling systems during the two observation periods reduced significantly CH4 concentrations in the barn when the cooling system in the feeding area was switched off. Based on methodological choices due to the specific barn typology, parameters related to animals can provide information on the variation of gas concentrations in the barn environment in hot climate conditions
Coping Strategies, Creativity, Social Self-Efficacy, and Hypercompetitiveness in Gambling Behaviors: A Study on Male Adolescent Regular Gamblers
The purpose of this research was to explore the cognitive and personality characteristics of male adolescent gamblers. Participants were 273 teenage males (M = 18.04, SD = 2.10) attending betting centers in Sicily, who completed self-report questionnaires on gambling, creativity, perceived social self-efficacy, hypercompetitiveness, and coping strategies. Pathological gamblers reported higher levels of avoidant coping strategies than occasional gamblers. They also scored higher on hypercompetitiveness than both occasional and problem gamblers. Further, problem gamblers scored higher than occasional gamblers on the complexity domain of creative personality. Finally, poor perceived social self-efficacy, higher levels of avoidant coping, and hypercompetitiveness predicted pathological gambling. Theoretical, psycho-educational, and clinical implications are discussed
Effect of sustained-release somatotropin on performance and grazing behavior of ewes housed at different stocking rates.
This study evaluated the effects of recombinant bovine somatotropin (bST; one injection of 320 mg per ewe) on milk production and composition and on the grazing behavior of multiparous ewes in the third to fourth lactation. Forty Comisana lactating ewes were divided into four groups: 1) untreated, grazing on natural pasture (botanical composition: 35% of Graminaceae, 49% of Fabaceae, 6% of Cruciferae, 10% of other families) at a low stocking rate (16 m2/d); 2) untreated, grazing at a high stocking rate (8 m2/d); 3) treated with bST, grazing at a low stocking rate; and 4) treated with bST, grazing at a high stocking rate. The diets of the ewes were supplemented with vetch and oat hay (500 g/d) and with concentrate (500 g/d). Treatment increased milk production (923.8 vs. 669.5 g/d) but had little effect on fat and protein contents. Administration of bST significantly increased herbage intake; the effect on intake was more marked at the high stocking rate. Under these grazing conditions, the treated ewes reduced selective intake behavior and, thus, achieved good feed intake despite the low biomass availability
Multi-vehicle refill scheduling with queueing
© 2017 We consider the problem of refill scheduling for a team of vehicles or robots that must contend for access to a single physical location for refilling. The objective is to minimise time spent in travelling to/from the refill station, and also time lost to queuing (waiting for access). In this paper, we present principled results for this problem in the context of agricultural operations. We first establish that the problem is NP-hard and prove that the maximum number of vehicles that can usefully work together is bounded. We then focus on the design of practical algorithms and present two solutions. The first is an exact algorithm based on dynamic programming that is suitable for small problem instances. The second is an approximate anytime algorithm based on the branch and bound approach that is suitable for large problem instances with many robots. We present simulated results of our algorithms for three classes of agricultural work that cover a range of operations: spot spraying, broadcast spraying and slurry application. We show that the algorithm is reasonably robust to inaccurate prediction of resource utilisation rate, which is difficult to estimate in cases such as spot application of herbicide for weed control, and validate its performance in simulation using realistic scenarios with up to 30 robots
Cross Sectional and Longitudinal Fuzzy Clustering of the NUTS and Positioning of the Italian Regions with Respect to the Regional Competitiveness Index (RCI) Indicators with Contiguity Constraints
In socio-economical clustering often the empirical information is represented by time-varying data generated by indicators observed over time on a set of subnational (regional) units. Usually among these units may exist contiguity relations, spatial but not only.In this paper we propose a fuzzy clustering model of multivariate time-varying data, the longitudinal fuzzy C-Medoids clustering with contiguity constraints. The temporal aspect is dealt with by using appropriate measures of dissimilarity between time trajectories. The contiguity among units is dealt with adding a contiguity matrix as a penalization term in the clustering model.The cross sectional fuzzy C-Medoids clustering with contiguity constraints is obtained considering one instant of time. The model is applied to the classification of the European NUTS on the basis of the observed dynamics of the Basic, Efficiency and Innovation subindexes of the Regional Competitiveness Index (RCI) 2013 and 2016. The positioning of the Italian regions is analyzed through the values of the medoids of the clusters and shows the peculiarities of the regions with respect to the subindexes either in single times or in the dynamic. Two contiguity constraints, one based on the European Western, Southern, Central and Northern geographic areas and one on the level of GDP—taken into account in the computation of the RCI—are also introduced in the models
Physico-empirical approach for mapping soil hydraulic behaviour
International audienceAbstract: Pedo-transfer functions are largely used in soil hydraulic characterisation of large areas. The use of physico-empirical approaches for the derivation of soil hydraulic parameters from disturbed samples data can be greatly enhanced if a characterisation performed on undisturbed cores of the same type of soil is available. In this study, an experimental procedure for deriving maps of soil hydraulic behaviour is discussed with reference to its application in an irrigation district (30 km2) in southern Italy. The main steps of the proposed procedure are: i) the precise identification of soil hydraulic functions from undisturbed sampling of main horizons in representative profiles for each soil map unit; ii) the determination of pore-size distribution curves from larger disturbed sampling data sets within the same soil map unit. iii) the calibration of physical-empirical methods for retrieving soil hydraulic parameters from particle-size data and undisturbed soil sample analysis; iv) the definition of functional hydraulic properties from water balance output; and v) the delimitation of soil hydraulic map units based on functional properties
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