816 research outputs found
Risks of hospitalization and drug consumption in children and young adults with diagnosed celiac disease and the role of maternal education: A population-based matched birth cohort study
Background: Celiac disease (CD) may affect healthcare use in children and young adults. Socio-economic factors
may act as a confounder or effect modifier. We assessed such hypotheses in a population-based birth cohort of
young celiac subjects and references matched by maternal education.
Methods: The cohort included all newborns recorded in the Medical Birth Register of Friuli-Venezia Giulia Region
(Italy) between 1989 and 2011. CD incident cases were identified through pathology reports, hospital discharges
and copayment exemptions and matched with up to five references by sex, year of birth and maternal education.
Cox regression models were used to estimate Hazard Ratios (HRs) for major causes of inpatient diagnosis and drug
prescription occurring after diagnosis in CD patients compared to references, stratifying by time of first event and
maternal education.
Results: We identified 1294 CD cases and 5681 references. CD cases had a higher risk of hospital admission for
any cause (HR: 2.34; 95 % CI 2.08-2.63) and for all major ICD9-CM categories except obstetric complications, skin
and musculoskeletal diseases, and injuries and poisoning. Prescription of all major ATC drug categories, except
dermatologicals and genito-urinary medications, was significantly increased in CD subjects. For most outcomes, HRs
were highest in the first year after CD diagnosis but remained significant after five or more years. HRs were similar
across different categories of maternal education.
Conclusions: Diagnosed CD subjects had a higher risk of hospitalization and medication use compared to the
general population, even five or more years after diagnosis, with no effect modification of maternal education
Experimental analysis of the influence of polymer solutions on performances and cavitation of small size pumps for professional appliances
Pumps used in professional appliances process a solution of water, soils residues and detergents. These affect vapor tension, viscosity and rheology of the solution, mainly due to the presence of surfactants and polymers. Only a few studies have been found on how these substances can influence pump performances. Therefore, an experimental analysis has been carried out with aqueous solutions of a detergent component, the Polyox WSR 301, in the concentration range of 100\u20137000 ppm, to evaluate their influence on pump performances and cavitation. Some properties of the solutions have been preliminary characterized with a rheometer. Then, each solution has been tested in a dedicated test rig, to compare the performance curves of a centrifugal pump used in professional warewashing machines with those obtained with pure water. A non-intrusive method, based on the investigation of high frequency vibrations and noise signals, has been developed to detect cavitation at its early stage of inception. It was observed that polymer mitigates cavitating pump vibrations, with a reduction of the acceleration to less than one g. The analysis has provided the data necessary for the successive development of a control strategy for pump operation in professional appliances
Influence of Polymer Solution on Pump Performances
5In professional warewashing machines, as for example the model of Electrolux Rack Type, the working conditions of the pump are affected by the operating fluid properties, which are different from those of pure water. In fact, the actual trend in this kind of professional appliances is to reduce both energy consumption and time needed for cleaning process: this involves short washing cycles conducted at low temperatures with a solution of water and highly concentrated chemistry. Detergents contain different components and additives, as polymers and surfactants, which can affect the performance of the pump, including cavitation inception conditions. Cavitation leads to flow instabilities, affecting pump performances and inducing an increment in the level of vibrations and noise. While cavitation phenomena in Newtonian fluids is well known, particularly as far as pure water is concerned, in literature there are also various studies on cavitating flows in presence of diluted solutions of polymers additives in water, but only few studies are available regarding the effect of detergent components on pumps cavitation and, in general, on pumps performances. The wide range of variables affecting the phenomenon has led to the development of a laboratory rig for testing centrifugal pumps with aqueous solutions representative of those used in the warewashing sector [1]. This paper presents the results of tests performed with various solutions of a polymer (Polyox WSR301) in water. A rheometric analysis has been previously performed on samples of some of the tested solutions, for characterizing their behavior in terms of both viscosity in laminar conditions and their classification as “diluted” or “concentrated”. For each solution, the resulting performance curves of the pump are then compared with those obtained with pure water.openopenBurlon, F.; Micheli, D.; Furlanetto, R.; Simonato, M.; Cucit, V.Burlon, Fabio; Micheli, Diego; Furlanetto, R.; Simonato, M.; Cucit, Valentin
Cavitation Detection and Prevention in Professional Warewashing Machines
Cavitation is a phenomenon characterised by the presence of vapour bubbles in the fluid led by a local drop in pressure. In literature it is well known the impact on cavitation of pressure and temperature of pure water, but there are only few studies analysing how the presence of certain components of detergents and additives can influence the phenomenon. The impact of detergents and additives could be explained by the modified viscosity and rheology of the solution but also by the variation in the vapour tension. Most of these effects are due to the presence of surfactants and polymers in the solution. Cavitation in dynamic pumps is an important aspect that needs to be monitored and prevented, because it can cause damages affecting pump performances and inducing an increment in the level of vibration and noise. In professional warewashing machines, as for example the models of Electrolux Rack Type, this phenomenon can affect the operating functionalities of the machine. An experimental pump test rig has been realized with the aim of studying and monitoring the influence of these parameters on cavitation inception. This test rig permits measuring the pump performances at various operating conditions, in order to obtain its characteristic curves, and also forcing cavitation to measure its Net Positive Suction Head required (NPSHr) at different flow rates. The pump test rig allows also testing various configurations of the pump at different cavitation conditions, obtained by changing not only the suction pressure and temperature of the fluid but also its properties, adding detergents and additives. Cavitation inception can be detected measuring both the corresponding prevalence decrease and the change of vibration and noise level
Transient model of a Professional Oven
Tackling the climate change by reducing energy consumption is among the biggest, most urgent challenges society is facing and requires a continuous efficiency improvement of thermal systems. Appropriate design strategies, developed a priori and then experimentally validated according to suitable test protocols on a prototype, are needed in order to reach potential energy saving targets. These strategies can successfully be implemented in the food service sector, where cooking appliances, in particular, present many possibilities for improving energy savings. Therefore, a valuable design methodology should take into account not only steady state operating conditions but also the transient behaviours of the device, which must be described by means of specially developed theoretical dynamic models. The operating profile of an oven, for example, consists of a sequence of unsteady phases (cavity heating-up, food introduction and extraction, switching from one cooking mode to another) interspersed with steady cooking phases. The dynamic model presented in this paper defines the energy conservation equations of a professional oven, where a high temperature thermal source positioned inside its cavity produces thermal power radiated and modulated over time, according to a suitable control strategy. In particular, when the temperature in the cooking zone of the cavity has reached a specified set point, this is thermostatically controlled in time, depending on the cooking phase. The resulting equation system is then solved by means of numerical methods. With this code, it is possible to support the design phase of both the structure and the control strategy of the oven. It permits, for example, to get a general understanding of the best possible configurations and combinations of insulation materials for the cavity walls or, with reference to the control strategy, to simulate different cooking procedures, with the aim of optimizing the operating sequence of the oven, reaching the maximum energy saving without reducing the cooking quality. The code, validated by comparison with a set of experimental data obtained with a current production model, will be applied in the design phase of a new line of high efficiency professional ovens
Correlating Noble Rot Infection of Garganega Withered Grapes with Key Molecules and Odorants of Botrytized Passito Wine
Experimental passito wines with dierent percentages of naturally noble-rotten grapes of the Garganega variety were analyzed to evaluate key molecules and odorants related to the typical aroma and sensory profile of botrytized passito wine. Remarkable changes in the concentration of 1-octen-3-ol, 4-terpineol, benzaldehyde, N-(3-methylbutyl)acetamide, and sherry lactone 1 and 2 were observed between sound and noble-rotten wines. Wines were perceived to be dierent for floral, honey, figs, apricot, and caramel scents. By partial least square regression these descriptors were well correlated to samples. An important positive contribution of sherry lactones, N-(3-methylbutyl)acetamide, vanillin, benzaldehyde, and -butyrolactone to honey, apricot, and caramel was observed. It is conceivable that oxidative eects of Botrytis cinerea infection play an important role in the genesis of these chemical and sensory aroma markers. This study provides a predictive tool for winemakers that use natural grape withering to produce wines whose aroma profile is not standardized due to the seasonal variation of noble rot incidence
Tactile discrimination of material properties: application to virtual buttons for professional appliances
An experiment is described that tested the possibility to classify wooden, plastic, and metallic objects based on reproduced auditory and vibrotactile stimuli. The results show that recognition rates are considerably above chance level with either unimodal auditory or vibrotactile feedback. Supported by those findings, the possibility to render virtual buttons for professional appliances with different tactile properties was tested. To this end, a touchscreen device was provided with various types of vibrotactile feedback in response to the sensed pressing force and location of a finger. Different virtual buttons designs were tested by user panels who performed a subjective evaluation on perceived tactile properties and materials. In a first implementation, virtual buttons were designed reproducing the vibration recordings of real materials used in the classification experiment: mainly due to hardware limitations of our prototype and the consequent impossibility to render complex vibratory signals, this approach did not prove successful. A second implementation was then optimized for the device capabilities, moreover introducing surface compliance effects and button release cues: the new design led to generally high quality ratings, clear discrimination of different buttons and unambiguous material classification. The lesson learned was that various material and physical properties of virtual buttons can be successfully rendered by characteristic frequency and decay cues if correctly reproduced by the device
Does It Ping or Pong? Auditory and Tactile Classification of Materials by Bouncing Events
Two experiments studied the role of impact sounds and vibrations in classification of materials. The task consisted of feeling on an actuated surface and listening through headphones to the recorded feedback of a ping-pong ball hitting three flat objects respectively made of wood, plastic, and metal, and then identifying their material. In Experiment 1, sounds and vibrations were recorded by keeping the objects in mechanical isolation. In Experiment 2, recordings were taken while the same objects stood on a table, causing their resonances to fade faster due to mechanical coupling with the support. A control experiment, where participants listened to and touched the real objects in mechanical isolation, showed high accuracy of classification from either sounds (90% correct) or vibrations (67% correct). Classification of reproduced bounces in Experiments 1 and 2 was less precise. In both experiments, the main effect of material was statistically significant; conversely, the main effect of modality (auditory or tactile) was significant only in the control. Identification of plastic and especially metal was less accurate in Experiment 2, suggesting that participants, when possible, classified materials by longer resonance tails. Audio-tactile summation of classification accuracy was found, suggesting that multisensory integration influences the perception of materials. Such results have prospective application to the nonvisual design of virtual buttons, which is the object of our current research
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