Flow configurations in a Y splitting-junction microchannel

In the present work, the flow field in a splitting-junction micro channel with a Y shape, which is the simplest geometry to be employed for heat and mass transfer in micro-devices such as micro-heat-exchangers and micro-mixers, is investigated experimentally using micro Particle Image Velocimetry (microPIV). The angular divergence in the Y splitting is changed, as well as the Reynolds number, in order to investigate the instantaneous and mean flow fields to determine which configurations are more suitable for practical applications. The results show that the flow configuration is strongly dependent on the Y shape angle, especially in the junction part, and that there is also a significant dependence on the Reynolds number

Experimental investigation on free surface vortices driven by tangential inlets

Particle Image Velocimetry (PIV) measurements have been carried out in order to analyze the structure of free surface vortices in a promoting geometry with two tangential inlets. Velocity fields associated to the free surface vortex have been obtained at different horizontal planes and Reynolds numbers. Average velocity fields have been calculated and tangential velocity profiles have been compared at different vortex stages and measurement planes. The results show that tangential flow is uniform along the vortex axis and it scales well with the average exit velocity. The tangential velocity profiles, in comparison to the potential behavior, show discrepancies especially at large distances from the vortex axis. Vorticity fields and circulation profiles have been also derived from the measured velocity fields and discussed. The circulation profiles increase along the vortex radius even at large distances from the vortex axis, so that the potential solution is not applicable at all. The comparison of tangential velocity and circulation profiles between promoted and free vortices, the last presented in a previous paper, shows that the tangential motion in a driven vortex is more intense and predominant over the sink effect (radial motion), except very close to the tank bottom, as in a forced configuration (i.e. rotating cylindrical tank)

The determination of velocity fluctuations in shear flows by means of PTV

The present study considers the effects of some parameters in image acquisition and analysis procedures in connection with the use of the Particle Tracking Velocimetry (PTV) technique. The interest is focused towards flow fields with large velocity gradients as shear flows; in the paper, velocity measurements by PTV are performed in a turbulent channel flow upstream and downstream of a backward facing step at low Reynolds numbers. This is a flow field largely investigated in the past with available numerical and experimental to make comparison with. Among the possible parameters to be chosen in particle image acquisition and analysis, the following are considered - the concentration of seeding particles in the imaged region; - the spatial resolution of the image acquisition system; - the parameters used in the image analysis algorithm

Investigation on bathtub vortex flow field by Particle Image Velocimetry

An experimental investigation on bathtub vortices has been performed by using Particle Image Velocimetry (PIV). Velocity fields associated to the free surface vortex were obtained at three horizontal planes and four Reynolds numbers, i.e. between 2400 and 11000 (calculated with reference to the exit hole diameter and the mean exit velocity). Due to the unsteady behavior of the low field, the vortex center positions have been identified and the vortex paths were reconstructed for all experiments. Average velocity fields have been calculated by aligning the vortex centers at each frame, in order to derive radial and tangential velocity profiles, to be compared at different Reynolds numbers and measurement planes. The results show that the radial motion assumes a potential behavior when it is near the exit hole, scaling quite well with the average exit velocity (thus with the corresponding Reynolds number). On the other hand, the tangential component is well approximated by the Rankine’s flow potential solution only near the free surface, the tangential velocity peak increment not being linearly proportional to the outlet velocity. Vorticity fields and circulation profiles have been derived from the measured velocity fields and discussed. Turbulence fluctuations statistical analysis gives also evidence of a clear dependence on Reynolds number and distance from the exit hole

Time-clustering of wave storms in the Mediterranean Sea

In this contribution we identify storm time-clustering in the Mediterranean Sea through a comprehensive analysis of the Allan Factor. This parameter is evaluated from long time series of wave height provided by oceanographic buoy measurements and hindcast re-analysis of the whole basin, spanning the period 1979-2014 and characterized by a horizontal resolution of about 0.1 degree in longitude and latitude and a temporal sampling of one hour (Mentaschi et al., 2015). The nature of the processes highlighted by the AF and the spatial distribution of the parameter are both investigated. Results reveal that the Allan Factor follows different curves at two distinct time scales. The range of time scales between 12 hrs to 50 days is characterised by a departure from the Poisson distribution. For timescales above 50 days, a cyclic Poisson process is identified. The spatial distribution of the Allan Factor reveals that the clustering at smaller time scales is present in the North-West of the Mediterranean, while seasonality is observed in the whole basin. This analysis is believed to be important to assess the local increased flood and coastal erosion risks due to storm clustering

Fulminant ischemic colitis with a fatal outcome after cocaine snorting: Case report and literature review

Abstract Snorting represents the most common route of administration for recreational powdered cocaine, and it is considered less dangerous than other routes of intake (i.e., intravenous; crack inhalation; etc.). A case of fulminant ischemic colitis with a fatal outcome, which occurred in a 19-year-old man after cocaine snorting, is presented in this report. Although several cases are reported in the literature, no one has involved people aged less than 20 years. The young man showed unspecific symptoms, which began about 2 h after the cocaine intake and the physicians were unable to make the diagnosis. This report may assist doctors treating young men who have consumed cocaine to consider this possible complication in all young adults (teenagers) in the presence of unspecific symptoms

Lean Six Sigma: A new approach to the management of patients undergoing prosthetic hip replacement surgery

Rationale, aims and objectives In 2012, health care spending in Italy reached €114.5 billion, accounting for 7.2% of the Gross Domestic Product (GDP) and 14.2% of total public spending. Therefore, reducing waste in health facilities could generate substantial cost savings. The objective of this study is to show that Lean Six Sigma represents an appropriate methodology for the development of a clinical pathway which allows to improve quality and to reduce costs in prosthetic hip replacement surgery. Methods The methodology used for the development of a new clinical pathway was Lean Six Sigma. Problem solving in Lean Six Sigma is the DMAIC (Define, Measure, Analyse, Improve, Control) roadmap, characterized by five operational phases which make possible to reach fixed goals through a rigorous process of defining, measuring, analysing, improving and controlling business problems. Results The following project indicated several variables influencing the inappropriate prolongation of the length of stay for inpatient treatment and corrective actions were performed to improve the effectiveness and efficiency of the process of care. The average length of stay was reduced from 18.9 to 10.6 days (-44%). Conclusion This article shows there is no trade-off between quality and costs: Lean Six Sigma improves quality and, at the same time, reduces costs

Outcomes of Abrupt Switch to Bevacizumab of Patients Undergoing Aflibercept Intravitreal Injections for Neovascular Age-Related Macular Degeneration in a Tertiary Center in Lombardy, Italy: A Real-Life Retrospective Analysis

To assess real-life anatomical and functional outcomes of switch to bevacizumab in patients undergoing aflibercept intravitreal injections for nAMD

A Low Rivaroxaban Plasma Level May Indicate Anticoagulation Undertreatment

Few reports have been published on the correlation between plasma concentrations of rivaroxaban and clinical outcome in patients who have experienced venous thromboembolism. This article describes the case of a 44-year-old woman who experienced deep vein thrombosis during anticoagulation therapy with rivaroxaban, with evidence of repeated low plasma levels of the drug. We postulate that the determination of plasma rivaroxaban anti-Xa activity can be useful in the evaluation of anticoagulation therapy in selected cases

INFRARED THERMOGRAPHY APPLIED TO POWER ELECTRON DEVICES INVESTIGATION

The aim of this paper is to give a presentation of the principal applications of Infrared Thermography for analysis and testing of electron devices. Even though experimental characterization could be carried out on almost any electronic devices and circuits, here IR Thermography for investigation of power semiconductor devices is presented. Different examples of functional and failure analysis in both transient and lock-in modes will be reported