799 research outputs found

    Smoke and thriving: An ecological study

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    Studies suggest a possible inverse correlation between smoking attitude and happiness levels. The present paper investigates the relation between males and females smoking prevalence and happiness levels in 155 countries worldwide. Analyses, after adjusting for socio-economic factors, reveal a different relationship between happiness and prevalence of tobacco smoking in the two genders. Countries with highest prevalence of males smoking show the lowest wellbeing levels (Beta coefficient: -0.350; P Value <0.001) while countries with highest prevalence of females smoking show the highest levels of wellbeing (Beta coefficient: 0.144; P Value: 0.030). The countries with the highest prevalence of people thriving are those with the highest prevalence of women smoking and the lowest prevalence of males smoking

    Melting of carbonated pelites at 8-13GPa: generating K-rich carbonatites for mantle metasomatism

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    The melting behaviour of three carbonated pelites containing 0-1wt% water was studied at 8 and 13GPa, 900-1,850°C to define conditions of melting, melt compositions and melting reactions. At 8GPa, the fluid-absent and dry carbonated pelite solidi locate at 950 and 1,075°C, respectively; >100°C lower than in carbonated basalts and 150-300°C lower than the mantle adiabat. From 8 to 13GPa, the fluid-present and dry solidi temperatures then increase to 1,150 and 1,325°C for the 1.1wt% H2O and the dry composition, respectively. The melting behaviour in the 1.1wt% H2O composition changes from fluid-absent at 8GPa to fluid-present at 13GPa with the pressure breakdown of phengite and the absence of other hydrous minerals. Melting reactions are controlled by carbonates, and the potassium and hydrous phases present in the subsolidus. The first melts, which composition has been determined by reverse sandwich experiments, are potassium-rich Ca-Fe-Mg-carbonatites, with extreme K2O/Na2O wt ratios of up to 42 at 8GPa. Na is compatible in clinopyroxene with DNacpx/carbonatite=10−18 D_{\text{Na}}^{{{\text{cpx}}/{\text{carbonatite}}}} = 10{-}18 at the solidus at 8GPa. The melt K2O/Na2O slightly decreases with increasing temperature and degree of melting but strongly decreases from 8 to 13GPa when K-hollandite extends its stability field to 200°C above the solidus. The compositional array of the sediment-derived carbonatites is congruent with alkali- and CO2-rich melt or fluid inclusions found in diamonds. The fluid-absent melting of carbonated pelites at 8GPa contrasts that at ≤5GPa where silicate melts form at lower temperatures than carbonatites. Comparison of our melting temperatures with typical subduction and mantle geotherms shows that melting of carbonated pelites to 400-km depth is only feasible for extremely hot subduction. Nevertheless, melting may occur when subduction slows down or stops and thermal relaxation sets in. Our experiments show that CO2-metasomatism originating from subducted crust is intimately linked with K-metasomatism at depth of >200km. As long as the mantle remains adiabatic, low-viscosity carbonatites will rise into the mantle and percolate upwards. In cold subcontinental lithospheric mantle keels, the potassic Ca-Fe-Mg-carbonatites may freeze when reacting with the surrounding mantle leading to potassium-, carbonate/diamond- and incompatible element enriched metasomatized zones, which are most likely at the origin of ultrapotassic magmas such as group II kimberlite

    The Melting of Carbonated Pelites from 70 to 700 km Depth

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    Phase assemblages, melting relations and melt compositions of a dry carbonated pelite (DG2) and a carbonated pelite with 1·1 wt % H2O (AM) have been experimentally investigated at 5·5-23·5 GPa and 1070-1550°C. The subsolidus mineralogies to 16 GPa contain garnet, clinopyroxene, coesite or stishovite, kyanite or corundum, phengite or potassium feldspar (≤8 GPa with and without H2O, respectively), and then K-hollandite, a Ti phase and ferroan dolomite/Mg-calcite or aragonite + ferroan magnesite at higher pressures. The breakdown of clinopyroxene at >16 GPa causes Na-rich Ca-carbonate containing up to 11 wt % Na2O to replace aragonite and leads to the formation of an Na-rich CO2 fluid. Further pressure increase leads to typical Transition Zone minerals such as the CAS phase and one or two perovskites, which completely substitute garnet at the highest investigated pressure (23·5 GPa). Melting at 5·5-23·5 GPa yields alkali-rich magnesio-dolomitic (DG2) to ferro-dolomitic (AM) carbonate melts at temperatures 200-350°C below the mantle geotherm, lower than for any other studied natural composition. Melting reactions are controlled by carbonates and alkali-hosting phases: to 16 GPa clinopyroxene remains residual, Na is compatible and the magnesio- to ferro-dolomitic carbonate melts have extremely high K2O/Na2O ratios. K2O/Na2O weight ratios decrease from 26-41 at 8 GPa to 1·2 at 16 GPa when K-hollandite expands its stability field with increasing pressure. At >16 GPa, Na is repartitioned between several phases, and again becomes incompatible as at <3 GPa, leading to Na-rich carbonate melts with K2O/Na2O ratios 1. This leaves the pressure interval of c. 4-15 GPa for ultrapotassic metasomatism. Comparison of the solidus with typical subducting slab-surface temperatures yields two distinct depths of probable carbonated pelite melting: at 6-9 GPa where the solidus has a negative Clapeyron slope between the intersection of the silicate and carbonate melting reactions at ∼5 GPa, and the phengite or potassium feldspar stability limit at ∼9 GPa. The second opportunity is related to possible slab deflection along the 660 km discontinuity, leading to thermal relaxation and partial melting of the fertile carbonated pelites, thus recycling sedimentary CO2, alkalis and other lithophile and strongly incompatible elements back into the mantl

    A Proposal for New Microclimate Indexes for the Evaluation of Indoor Air Quality in Museums

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    A correct artwork preservation requires strict values of several microclimate parameters, in particular temperature, humidity, and light. In existing museums, the evaluation of the effectiveness of current building plant systems and management is essential to avoid artwork deterioration. In this work, we propose the use of five simple performance indexes that use monitored data to estimate the suitability of the whole museum system in the maintenance of benchmark values of temperature, humidity, and light. The new indexes also take into account microclimate daily span and spatial homogeneity, which can represent a criticality in the preservative process. We apply these new indexes to the results of a monitoring campaign in Palazzo Blu, a museum in Pisa, which lasted for almost four months during a temporary exhibition on Toulouse-Lautrec works. The indexes show a mainly acceptable instantaneous microclimate, but HVAC (Heating, Ventilating and Air Conditioning) system improvement is necessary to avoid high thermo-hygrometric daily span. This methodology is useful for the identification of microclimate criticalities and can help the cooperation between conservation experts and professionals giving hints to improve museum internal microclimate. In case ofalready optimal microclimate, these indexes can be useful in more complex analyses, including simulations of possible retrofit actions, keeping microclimate suitability as a constraint

    Control of natural circulation loops by electrohydrodynamic pumping

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    The paper analyses the effect of electrohydrodynamic (EHD) pumping on the control of natural circulation loops (NCLs). The two major objectives of the investigation are: finding the optimal configuration of an EHD pump and demonstrating that the NCL flow direction can be inverted by exploiting the EHD phenomena. In the initial experimental set-up, we measured the static pressure rise given by an EHD pump made of three consecutive modules of point-ring electrodes for different dielectric fluids and electrode materials. When reversing the polarity of the applied DC voltage, we observed opposite pumping directions, suggesting the presence of two distinct EHD phenomena, inducing motion on opposite directions: ion-drag pumping and conduction pumping. The former was identified as a more efficient process compared to the latter. Based on these preliminary experiments, we built a NCL, operating with the fluid HFE-7100. Two oppositely mounted optimised pumping sections could be alternately activated, to promote clockwise or anticlockwise motion. In the first series of tests, alternately, the pumping sections were triggered prior to the heat input. In any case, the circulation followed the EHD pumping direction. In other tests, the electric field was applied when natural circulation was already present and the flow was reversed by means of opposite EHD pumping, at both polarities. Simply inverting the polarity of the applied voltage, we could alternate ion-drag and conduction pumping; in this way, we easily controlled the direction of motion by means of a single EHD pumping device

    Validation of SEAS, a Quasi-Steady-State Tool for Building Energy Audits

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    SEAS is an energy auditing software that can simulate residential, office, school, and hospital buildings, providing energy requirements for heating, domestic hot water production, ventilation, lighting, and other electrical uses. In order to validate this quasi-steady-state tool, we simulated in SEAS several reference cases (based on EN 15265 benchmark room) and a residential dwelling. We also used the dynamic simulation software TRNSYS and compared the results of the two software in terms of seasonal energy requirements for space heating and energy fluxes through the elements of the building envelope. Most of SEAS results are in good agreement with EN 15265 and with TRNSYS. Nonetheless, we pointed out that SEAS lacks in accuracy when it simulates high thermal inertia buildings with intermittent heating: for these particular cases, new correlations for dynamic parameters and reduction factors should be developed

    On Sustainable and Efficient Design of Ground-Source Heat Pump Systems

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    This paper is mainly aimed at stressing some fundamental features of the GSHP design and is based on a broad research we are performing at the University of Pisa. In particular, we focus the discussion on an environmentally sustainable approach, based on performance optimization during the entire operational life. The proposed methodology aims at investigating design and management strategies to find the optimal level of exploitation of the ground source and refer to other technical means to cover the remaining energy requirements and modulate the power peaks. The method is holistic, considering the system as a whole, rather than focusing only on some components, usually considered as the most important ones. Each subsystem is modeled and coupled to the others in a full set of equations, which is used within an optimization routine to reproduce the operative performances of the overall GSHP system. As a matter of fact, the recommended methodology is a 4-in-1 activity, including sizing of components, lifecycle performance evaluation, optimization process, and feasibility analysis. The paper reviews also some previous works concerning possible applications of the proposed methodology. In conclusion, we describe undergoing research activities and objectives of future works

    A comparative analysis of MAIDS and ISO13232 databases for the identification of the most representative impact scenarios for powered 2-wheelers in Europe

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    Objective: The ISO13232 standard provides guidelines and methodologies for research on the effectiveness of protective devices fitted to motorcycles. The accident database used to develop the standard was composed of 2 data sets from Hannover and Los Angeles, dating from 1996. This study aims to apply the methodology outlined in the standard to a more recent European accident database to determine whether the set of the 7 most relevant impact configurations identified in the ISO13232 are representative of the European context. Methods: The ISO13232 database was rebuilt from the data tables attached to the standard and processed according to the procedure described in ISO13232-Part 2, to ensure reproducibility of the results. The comparison data set was extracted from the Motorcycle Accidents In-Depth Study (MAIDS) database. Data were then coded, processed, and analyzed using the ISO13232 methodology. To eliminate any subjectivity in the selection process of the configurations, a new ranking criterion (configuration risk index, CRI) was implemented. The CRI combined the evaluation of an accident configuration's frequency of occurrence and its harmfulness. Results: Comparison of the frequency ranking of the impact configurations from the 2 databases revealed some notable differences. Five of the 10 most important configurations were common to both databases, although ranking order differed. CRI-based selection led to differences in ranking orders. The CRI allowed better identification of the most important configurations and it was employed to define the proposed new set of configurations. Conclusion: A new set of 7 accident configurations was defined by applying the ISO13232 procedure to the MAIDS data and ranking the results with a newly proposed method. The final set had only one configuration in common with those defined in the ISO13232, testifying to the importance of defining an updated and more representative set of configurations for the European context

    Laparoscopic peritoneal lavage. Our experience and review of the literature

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    NTRODUCTION: Over the years various therapeutic techniques for diverticulitis have been developed. Laparoscopic peritoneal lavage (LPL) appears to be a safe and useful treatment, and it could be an effective alternative to colonic resection in emergency surgery. AIM: This prospective observational study aims to assess the safety and benefits of laparoscopic peritoneal lavage in perforated sigmoid diverticulitis. MATERIAL AND METHODS: We surgically treated 70 patients urgently for complicated sigmoid diverticulitis. Thirty-two (45.7%) patients underwent resection of the sigmoid colon and creation of a colostomy (Hartmann technique); 21 (30%) patients underwent peritoneal laparoscopic lavage; 4 (5.7%) patients underwent colostomy by the Mikulicz technique; and the remaining 13 (18.6%) patients underwent resection of the sigmoid colon and creation of a colorectal anastomosis with a protective ileostomy. RESULTS: The 66 patients examined were divided into 3 groups: 32 patients were treated with urgent surgery according to the Hartmann procedure; 13 patients were treated with resection and colorectal anastomosis; 21 patients were treated urgently with laparoscopic peritoneal lavage. We had no intraoperative complications. The overall mortality was 4.3% (3 patients). In the LPL group the morbidity rate was 33.3%. CONCLUSIONS: Currently it cannot be said that LPL is better in terms of mortality and morbidity than colonic resection. These data may, however, be proven wrong by greater attention in the selection of patients to undergo laparoscopic peritoneal lavage
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