2,073 research outputs found

    Simulation of copper-water nanofluid in a microchannel in slip flow regime using the lattice Boltzmann method with heat flux boundary condition

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    Laminar forced convection heat transfer of water–Cu nanofluids in a microchannel is studied using the double population Thermal Lattice Boltzmann method (TLBM). The entering flow is at a lower temperature compared to the microchannel walls. The middle section of the microchannel is heated with a constant and uniform heat flux, simulated by means of the counter slip thermal energy boundary condition. Simulations are performed for nanoparticle volume fractions equal to 0.00%, 0.02% and 0.04% and slip coefficient equal to 0.001, 0.01 and 0.1. Reynolds number is equal to 1, 10 and 50.The model predictions are found to be in good agreement with earlier studies. Streamlines, isotherms, longitudinal variations of Nusselt number and slip velocity as well as velocity and temperature profiles for different cross sections are presented. The results indicate that LBM can be used to simulate forced convection for the nanofluid micro flows. They show that the microchannel performs better heat transfers at higher values of the Reynolds number. For all values of the Reynolds considered in this study, the average Nusselt number increases slightly as the solid volume fraction increases and the slip coefficient increases. The rate of this increase is more significant at higher values of the Reynolds number

    Factors affecting use and understanding of nutrition information on food labels: evidences from consumers

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    In the past years, European population has experienced an increase in several chronic diseases linked to dietary and lifestyle factors. In particular obesity is increasing at an alarming rate all over Europe, while warnings about its diffusion have intensified. As a result nutrition-related measures are highly ranked in the agenda of the European Union political priorities. Specifically, at the end of 2011 the EU introduced new rules on food labelling requirements by adding a nutritional declaration. In this context the current paper explores factors affecting use and understanding of nutrition information on food labels in Italy and provides potentially useful assistance for the implementation of new nutrition labelling. Results of a direct survey on a random sample of 400 food shoppers identifies different profiles of consumers, through the use of PCA and Cluster Analysis. Main findings reveal the need to focus primarily on education campaigns and provide specific indications for developers and marketers as well as government bodies that are interested in designing consumer communication strategies and effective health programs

    Impact of hypoglycemia on patients with type 2 diabetes mellitus and their quality of life, work productivity, and medication adherence.

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    BackgroundThe purpose of this study was to determine the characteristics of adults with type 2 diabetes mellitus (T2DM) that correlate with greater risk of hypoglycemia and determine the impact of hypoglycemia on health-related quality of life, work productivity, and medication adherence from a patient perspective.MethodsData from a large web-based survey were retrospectively analyzed. Adults with a diagnosis of T2DM taking antihyperglycemic agents were included in the analysis. Participants with knowledge of their hypoglycemic history were divided into three groups: those experiencing recent hypoglycemia (previous 3 months), those experiencing nonrecent hypoglycemia, and those never experiencing hypoglycemia.ResultsOf the participants with T2DM taking antihyperglycemic agents who were knowledgeable of their hypoglycemia history, 55.7% had ever experienced hypoglycemia. Of those, 52.7% had recent hypoglycemia. Compared with those who never experienced hypoglycemia, those who experienced hypoglycemia tended to: be younger; be more aware of their glycated hemoglobin (HbA1c) levels; have higher HbA1c levels; have a higher body mass index; have higher Charlson Comorbidity Index scores; be on insulin, sulfonylureas, and/or glucagon-like peptide-1 agonists; and be less adherent to their antihyperglycemic agents. Hypoglycemia interfered with social activities, caused more missed work (absenteeism), more impairment while at work (presenteeism), and decreased overall work productivity compared with patients who had never experienced hypoglycemia. Overall health-related quality of life, as determined by the Short Form-36 health questionnaire, was negatively impacted by hypoglycemia. Both Physical and Mental Summary scores were significantly lower for the recent hypoglycemia and nonrecent hypoglycemia groups compared with the never hypoglycemia group.ConclusionHypoglycemia can negatively impact many aspects of life. Greater awareness of those who are at risk for developing hypoglycemia can lead to the development of measures (eg, patient and physician education) to prevent future hypoglycemia episodes

    Ferromagnetic features on zero-bias conductance peaks in ferromagnet/insulator/superconductor junction

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    We present a formula for tunneling conductance in ballistic ferromagnet/ferromagnetic insulator/superconductor junctions where the superconducting state has opposite spin pairing symmetry. The formula can involve correctly a ferromagnetism has been induced by effective mass difference between up- and down-spin electrons. Then, this effective mass mismatch ferromagnet and standard Stoner ferromagnet have been employed in this paper. As an application of the formulation, we have studied the tunneling effect for junctions including spin-triplet p-wave superconductor. The conductace spectra show a clear difference between two ferromagnets depending upon the way of normalization of the conductance. Especially, a essential difference is seen in zero-bias conductance peaks reflecting characteristics of each ferromagnets. From obtained results, it will be suggested that the measurements of the tunneling conductance in the junction provide us a useful information about the mechanism of itinerant ferromagnetism in metal.Comment: 8 pages, 8 figures, references added to the first versio

    Preventing Household Food Waste in Italy: A Segmentation of the Population and Suggestions for Action

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    Household food waste represents one of the main challenges threatening the sustainability of modern food systems globally. As is widely recognised, a deeper understanding of wasteful behaviour profiles is the starting point of designing intervention strategies. The overall objective of this research is to explore the role of psychological factors that influence household wasteful food behaviour in Italy and to profile consumers with heterogeneous personal attitudes towards wasting food. Starting with data collected through a web-based survey realized on a sample of 530 individuals responsible for household shopping, a principal component analysis and a two-step cluster analysis revealed three different segments of consumers with heterogeneous wasteful behaviours. The clusters differ in relation to psychological factors, such as moral attitudes and concerns about and intentions to reduce food waste. The study findings provide insights for implementing prevention, reduction, and recovery strategies tailored to these different consumer profiles

    Food waste as a consequence of an inefficient consumer’s choices: a microeconomic approach

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    This study frames the household food waste challenge in the microeconomic theory context by proposing a model that considers food waste a consequence of inefficient consumer choices. A data envelopment analysis (DEA) methodology was applied to factor consumer’s efficiency level dimension, starting from data collected through a web survey conducted in Italy with a sample of 530 individuals responsible for their households’ food-shopping. The findings confirm that food waste is a complex issue, affected by both behavioural and psychological factors, synthesized in three indices constructed with fuzzy analysis. The results show that the shopping behaviour index generates a higher average efficiency score for food waste minimization than the food waste concerns and moral attitudes indices. Furthermore, those drivers have different efficiency levels in reducing food waste with reference to gender, age, family composition, and educational level. The results have several implications for policymakers: they highlight the need to implement tailored educational and information campaigns that consider the most important targets identified, such as large families with children, young people, and me

    Gated Mode Superconducting Nanowire Single Photon Detectors

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    Single Photon Detectors (SPD) are fundamental to quantum optics and quantum information. Superconducting Nanowire SPDs (SNSPD) [1] provide high performance in terms of quantum efficiency (QE), dark count rate (DCR) and timing jitter [2], but have limited maximum count rate (MCR) when operated as a free-running mode (FM) detector [3, 4]. However, high count rates are needed for many applications like quantum computing [5] and communication [6], and laser ranging [7]. Here we report the first operation of SNSPDs in a gated mode (GM) that exploits a single photon triggered latching phenomenon to detect photons. We demonstrate operation of a large active area single element GM-SNSPD at 625MHz, one order of magnitude faster than its FM counterpart. Contrary to FM-SNSPDs, the MCR in GM can be pushed to GHz range without a compromise on the active area or QE, while reducing the DCR
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