350 research outputs found

    Towards practical guidelines for conversion from fixed to reconfigurable manufacturing automation systems

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    It is generally considered that economic feasibility of a reconfigurable manufacturing system is only attainable if the system is defined to be reconfigurable at the outset of its design. In this work we consider the potential exception to this perception, in the context of a common industrial scenario where a specialized and expensive manufacturing machine or system will otherwise be rendered useless due to loss of business of the particular product being manufactured. Specific guidelines to convert from a fixed to a reconfigurable system are proposed, and evaluated through a case study. It is shown that under certain conditions, reconfigurable manufacturing systems may be economically feasible even if they are developed through the modification of pre-existing dedicated systems.peer-reviewe

    KINEMATIC AND DYNAMIC ANALYSIS OF SPRINT START

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    Aims of this study were the tuning of the methods for kinematic and dynamic analysis of sprint start and the assessment of their relevance for field practice. Data collection was performed by means of an Elite Motion Analysis System (two cameras,3D) at 100 Hzi and a Kistler force platform (type 9281b ) at 500 Hz. Three elite athletes participated in the study; each subject performed three trials. statistical analysis ( ONEWAY ANOVA - SPSSPC software package) was performed in order to highlight significant differences ( F>0.05 ) between the subjects. The start movement was divided into three temporal phases: release of the starting block, landing on first supported push off from platform. significant differences were observed with respect to hip horizontal linear velocity within these phases (F > 0.02-0.001-0.0003) between the subjects. In order to give a complete description of the movement pattern four groups of variables were selected: 1)LINEAR DISPLACEMENTS. Eighteen variables were studied ; thirteen of them show significant differences index of different positions on the starting blocks -and different movement pattern during push-of f . 2)ANGULAR DISPLACEMENTS. Thirty-five variables were selected; eighteen show significant differences. 3) LINEAR AND ANGULAR-VEMCITIES Of the 54 variables studied (20 linear var. and 34 angular var.) , 38 (13 linear var. and 15 angular var. ) shows significant differences. 4)DYNAMIC DATA. We studied 62 variables, 26 of which showed significant differences. Exit velocity from starting blocks is influenced by the force produced during the first support phase and by the kinematics of the body segments. The different results obtained by the athletes in hip horizontal velocity, can be explained with the significant differences observed with respect to kinematic and dynamic of the phases of start studied. Main variables that shows significant differences are: hip, knee and ankle peak angular velocities, duration of first support phase and joint moments during push-off from first support phase. These variables seems to be logically related with the index of performance,hip horizontal velocity

    Mediterranean Sea large-scale low-frequency ocean variability and water mass formation rates from 1987 to 2007: A retrospective analysis

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    We describe a synthesis of the Mediterranean Sea circulation structure and dynamics from a 23-year- long reanalysis of the ocean circulation carried out by Adani et al. (2011). This mesoscale permitting dynamical reconstruction of past ocean variability in the Mediterranean Sea allows the study of the time-mean circulation and its low frequency, decadal, components. It is found that the time-mean circu- lation is composed of boundary and open ocean intensified jets at the border of cyclonic and anticyclonic gyres. The large scale basin circulation is generally characterized in the northern regions by cyclonic gyres and in its southern parts by anticyclonic gyres and eddy-dominated flow fields, with the exception of the Tyrrhenian and the northern Ionian Sea. The time-mean Tyrrhenian Sea circulation is dominated by cyclonic gyres of different intensity and intermittency. The northern Ionian Sea circulation, however, reverses in sign in two ten-year periods, the first in 1987–1996 and the second in 1997–2006, which is here called the Northern Ionian reversal phenomenon. This reversal is provoked by the excursion of the Atlantic-Ionian Stream from the middle to the northern parts of the basin. The decadal variability of other parts of the basin is characterized by changes in strength of the basin scale structures. The water mass formation rates and variability are dominated by event-like periods where the intermediate and deep waters are formed for 2–3 years at higher rates. The largest deep water formation events of the past 23 years occurred separately in the western and eastern Mediterranean basin: the first coincided with the Eastern Mediterranean Transient (Roether et al., 1996) and the second with the western Mediterranean deep water formation event in 2005–2006 (Smith et al., 2008). A new schematic of the basin-scale circu- lation is formulated and commented.Published318-3324A. Oceanografia e climaJCR Journa

    Compared clinical efficacy and bone metabolic effects of low-dose deflazacort and methyl prednisolone in male inflammatory arthropathies: a 12-month open randomized pilot study.

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    Objective. To evaluate: (i) a correct equivalence ratio of clinical efficacy between low-dose deflazacort (DFZ) and methyl prednisolone (MP); and (ii) bone metabolic effects of low-dose DFZ and MP in the treatment of male RA and PsA. Methods. A total of 21 male patients with active RA or PsA, naive to steroid treatment were chosen for the study. Group I: 10 patients treated for 6 months with DFZ 7.5 mg, calcium, cholecalciferol and a DMARD; for the following 6 months with MP 4 mg, calcium, cholecalciferol and a DMARD. Group II: 11 patients treated for 6 months with MP 4 mg, calcium, cholecalciferol and a DMARD; for the following 6 months with DFZ 7.5 mg, calcium, cholecalciferol and a DMARD. At day 0, 90, 180, 240 and 360 evaluation of ACR improvement criteria; a blood sample for total and bone-specific ALP, calcium, phosphorus, PTH, SHBG, estradiol, ACTH, osteocalcin, LH, OPG; a sample of urine for calcium, phosphorus, creatinine and DPD. Results. 13/21 patients (6/10 Group I; 7/11 Group II) reached ACR 20 at 6 months; 14/21 (7/10 Group I, 7/10 Group II) at 12 months. Only at the third month we observed in Group II vs Group I a reduction of OPG (24% vs 6%, P= n.s.); ALP (P < 0.001) and osteocalcin (P = 0.006) decreased in both groups from the third month; DPD decreased in both groups only from the sixth month (P = 0.002). Conclusions. The correct equivalence ratio of DFZ to MP is 1.875:1, and of DFZ to prednisolone 1.5:1. We found a relative prevalence of bone resorption compared to bone formation in the first 6 months of treatment. The trend of OPG requires further investigation

    The Black Sea Physics Analysis and Forecasting System within the Framework of the Copernicus Marine Service

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    This work describes the design, implementation and validation of the Black Sea physics analysis and forecasting system, developed by the Black Sea Physics production unit within the Black Sea Monitoring and Forecasting Center as part of the Copernicus Marine Environment and Monitoring Service. The system provides analyses and forecasts of the temperature, salinity, sea surface height, mixed layer depth and currents for the whole Black Sea basin, excluding the Azov Sea, and has been operational since 2016. The system is composed of the NEMO (v 3.4) numerical model and an OceanVar scheme, which brings together real time observations (in-situ temperature and salinity profiles, sea level anomaly and sea surface temperature satellite data). An operational quality assessment framework is used to evaluate the accuracy of the products which set the basic standards for the future upgrades, highlighting the strengths and weaknesses of the model and the observing system in the Black Sea

    Marine climatological datasets for the Maltese Islands

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    During the last 25 years of activity, the Physical Oceanography Research Group, previously known as the PO-Unit, and currently established within the Department of Geosciences of the University of Malta, has been promoting the downscaling of broad scope marine core services to higher resolution local scale domains for the Maltese Islands. Several services are delivered either by an intrinsic data elaboration or by making use of and integrating the COPERNICUS Marine Environment Monitoring Service (CMEMS) data to local marine data streams. Local observations are also integrated with higher resolution forecasts for the preparation and provision of dedicated services that address real specific needs of sub-regional and coastal users. This effort has yielded valuable climatological datasets covering the Maltese coastal waters and spanning over several years. This work focusses on the climatologies derived from numerical models and satellites, and compiled within the Interreg MED programme AMAre (Actions for Marine Protected Areas) project.peer-reviewe
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