243 research outputs found

    Revision of the first Carboniferous palaeofloristic locality discovered in Argentina

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    The first Carboniferous palaeofloristic locality recognized in Argentina is situated to the south of the Sierra Chica de Zonda in San Juan Province, Argentina. The fossiliferous site known as Retamito or Río del Agua provided plant remains which were studied by the Polish scientist Ladislaus Szajnocha in 1891. Szajnocha proposed an early Carboniferous age for the assemblage and described some species of lycophytes and sphenophytes, and foliage of cordaitalean and probable pteridosperms. Subsequent studies of this outcrop and its palaeontological content have been few, and a new interdisciplinary approach is needed. The succession is interpreted as fluvial-deltaic in origin, with intercalation of shallow marine deposits, which provided diagnostic plant components of the Nothorhacopteris/Botrychiopsis/Ginkgophyllum Biozone of the late Carboniferous in Argentina. Palynological assemblages recovered from the same strata contain bisaccate taeniate pollen and spores (e.g. Striatosporites heyleri) that support an age probably not older than early Moscovian.Fil: Correa, Gustavo Alejandro. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto y Museo de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cesari, Silvia Nelida. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

    Study on thermal performance of a PCM enhanced hydronic radiant floor heating system

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    Abstract Radiant floor systems enhanced with Phase Change Materials (PCMs) could achieve significant energy savings while improving the thermal comfort of occupants in lightweight buildings. Effective integration of PCMs typically requires customised solutions based on a comprehensive analysis due to their complex nature. The objective of the present study is the experimental and numerical investigation of a hydronic radiant floor heating system integrated with macroencapsulated PCM. Experimental tests were carried out on a laboratory-scale by the University of Ferrara, Italy, within the H2020 European project IDEAS. A 2D model was then implemented in COMSOL Multiphysics and calibrated in steady as well as in transient state according to the experimental tests. The behaviour of the system, including temperature distribution and heat flux, were analysed under different conditions. The impact of using dry and wet sand, as well as the effect of the position of PCM – above or under heating pipes – on thermal performance, were investigated. Results showed that the use of high thermal conduction in mortar increases much faster the overall performance of the PCM integrated underfloor heating system. Furthermore, the coupling technology with PCM containers installed under piping significantly enhances the positive effect of wet sand

    A new Late Triassic phytogeographical scenario in westernmost Gondwana

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    Floral provincialism within the Southern Hemisphere during the Late Triassic (230 Ma) is characterized by the Ipswich and Onslow provinces, recognized originally in eastern Gondwana. However, new palynological assemblages from the Ischigualasto Formation, northwestern Argentina (231–225 Ma), change the phytogeographic interpretation for the Carnian–Norian in the westernmost Gondwana, which was previously considered part of the southern floral Ipswich province. Here we show the presence of diagnostic Euramerican species within assemblages dominated by Gondwanan taxa that allows us to refer the palynofloras to the Onslow province. Our new data extend the Onslow floral belt, previously recognized from the western edge of Tethys to Timor, to the western margin of South America. This has implications for palaeophytogeography, palaeoclimate reconstructions and the palaeoecology of a Triassic ecosystem, which has yielded significant vertebrate remains and is regarded important in the early evolution of groups such as the Dinosauria.Fil: Cesari, Silvia Nelida. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Colombi, Carina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto y Museo de Ciencias Naturales; Argentin

    Role of phase change materials in backfilling of flat-panels ground heat exchanger

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    The behaviour of a multi-source heat pump system coupled with phase change materials (PCMs) is discussed in this manuscript, as based on selected data collected during one-year testing at the TekneHub Laboratory of the University of Ferrara (Italy), as a synergic prototype setup of two European projects: IDEAS, an H2020 project, and CLIWAX, an EFDR project. Three geothermal loops of novel shallow FlatPanels ground heat exchangers (GHX) provide the coupling of a water-to-water heat pump with the ground, as backfilled with sand, a mixture of sand and granules with paraffins and containers filled in with hydrated salts. Furthermore, two hybrid photovoltaic panels and a dry-cooler complete the exploitable thermal sources landscape. Finally, a control unit manages all the elements for the exploitation of the different thermal sources. How the increased underground thermal energy storage is driven by PCMs has been investigated by means of specific tests, and compared with the standard case of backfilling sand. Results confirm that PCMs can compensate peak loads occurring during hard weather conditions. Good performances of the multi-source heat pump were found, with a winter coefficient of performance always higher than 5. Finally, the application of PCM in summer should be preferred in climatic zones with hot summers and cold winters, With evidence, latent heat, thermal conductivity and melting point of PCMs should be tuned accordingly to the energy requirements and the local ground thermal conditions. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

    Energy savings in hospital patient rooms: the role of windows size and glazing properties

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    Abstract Large windows with increased exposure to daylight have strong positive effects on the well-being of building occupants and can provide energy savings when appropriate glazing specifications are employed. The work evaluates the impact of different window sizes and glazing on heating and cooling energy needs in a hospital patient room, in order to investigate the energy savings achievable by adopting wider openings and to identify the most effective glazing types. Simulations have been conducted for different commercially available glazing systems. The authors analyzed the energy performance of a base case window with 25% Window-to-Wall Ratio (WWR) and of a wall-to-ceiling window with 77% WWR, in rooms facing the four different orientations and located in Bologna, Italy. Results show that the adoption of wider windows with appropriate glazing can lower the heating and cooling energy demand

    Afloramientos carboníferos en la quebrada La Herradura, provincia de San Juan (oeste de Argentina), revisados: edad de las transgresiones.

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    At the outcrops of the Tupe Formation in the La Herradura Creek, San Juan Province, two transgressive events are recorded, which range from few meters to tens of meters in thickness. These strata correspond to the stratotype of the faunal Tivertonia jachalensis-Streptorhynchus inaequiornatus Biozone. An evaluation of the timing of the two marine transgressions is made on the basis of palynological assemblages and available radiometric ages. A short-lived transgression is recorded in the latest Bashkirian-early Moscovian, and then a substantial sea level fall took place forming an irregular incision surface. Later, a major high eustatic sea-level occurred during the middle Moscovian resulting in a more important marine ingression. The palynological assemblages associated to the older transgressive event indicate the presence of the Raistrickia densa-Convolutispora muriornata (DM) Biozone (Subzone B). Palynofloras referred to the Subzone C of the DM Biozone characterize the strata of the younger transgression that also bear marine fauna of the Tivertonia jachalensis-Streptorhynchus inaequiornatus Biozone. Correlations with other Pennsylvanian outcrops in the region give support to the stratigraphic scheme here proposed.En los afloramientos de la Formación Tupe en la quebrada de La Herradura, provincia de San Juan, se registran dos eventos transgresivos, cuya magnitud varía desde unos pocos metros a decenas de metros de espesor. Estos estratos corresponden al estratotipo de la biozona faunística Tivertonia jachalensis-Streptor- hynchus inaequiornatus. En esta contribución se presenta una evaluación y ajuste de la edad de las dos transgresiones marinas, sobre la base de las asociaciones palinológicas y las dataciones radiométricas disponibles. Una transgresión de corta duración se registró en el Bashkiriano tardío-Moscoviano temprano, a la que siguió una sustancial caída del nivel del mar, y originó una superficie de incisión irregular. Posteriormente, significativas condiciones de mar alto se produjeron durante el Moscoviano medio, lo que resultó en una más importante ingresión marina. Las asociaciones palinológicas relacionadas con el evento más antiguo pueden ser asignadas a la Subzona B de la Biozona Raistrickia densa-Convolutispora muriornata (DM). Palinofloras referidas a la Subzona C de la Biozona DM caracterizan los estratos de la transgresión más joven, donde también se reconoce la fauna marina de la Biozona Tivertonia jachalensis- Streptorhynchus inaequiornatus. Las correlaciones con otros afloramientos pennsylvanianos en la región dan soporte al esquema estratigráfico aquí propuesto.Fil: Perez Loinaze, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Limarino, Carlos Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Cesari, Silvia Nelida. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "bernardino Rivadavia"; Argentin

    The Biozone Pakhapites fusus-Vittatina subsaccata in the Patquía Formation (Permian), Precordillera of La Rioja, Argentina

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    La Formación Patquía es una de las pocas unidades neopaleozoicas de la Cuenca Paganzo que carecía de detallados estudios palinológicos. Doce muestras obtenidas de la sección media, depositada en un ambiente marino costero, en el área de Cerro Veladero (provincia de La Rioja) han permitido caracterizar su contenido palinológico. Todas las asociaciones recuperadas están dominadas por granos de polen, con un importante porcentaje de granos teniados. Se realiza una detallada comparación con otras palinofloras de Argentina y Brasil. La presencia de varias especies de Vittatina y Protohaploxypinus junto con Weylandites magmus, Pakhapites fusus y Converrucosisporites confluens Morphon sustentan su correlación con la Biozona Pakhapites fusus - Vittatina subsaccata que define el más temprano Cisuraliano en Argentina.The Patquía Formation is one of the few neopaleozoic units from the Paganzo Basin lacking detailed palynological studies. twelve samples from the midsection, deposited in a coastal marine environment in the area of cerro Veladero (La rioja Province) allowed us to characterize their palynologi- cal content. All associations recovered are dominated by pollen grains, with a important percentage of taeniate pollen. A detailed comparison is made with other associations from Argentina and Brazil. the presence of sev- eral species such as Protohaploxypinus and Vittatina together with Pakhapites fusus, Weylandites magmus and Converrucosisporites confluens Morphon sustains its correlFil: Cesari, Silvia Nelida. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Perez Loinaze, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Limarino, Carlos Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentin

    Olfaction and gustation in blindness: a state of the art of the literature

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    To date, there are quite a few studies assessing olfaction and gustation in blindness, with great variability in sample size, participants' age, blindness onset and smell and taste evaluation methods. Indeed, the evaluation of olfactory and gustatory performance can differ depending on several factors, including cultural differences. Therefore, here we analysed through a narrative review, all the works reporting a smell and taste assessment in blind individuals during the last 130 years, trying to summarize and address the knowledge in this field

    Emotional management and biological markers of dietetic regimen in chronic kidney disease patients

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    The aim of the study was to investigate the association between psychological characteristics and biological markers of adherence in chronic kidney disease patients receiving conservative therapy, hemodialysis, peritoneal dialysis (PD), or kidney transplantation. Seventy-nine adult patients were asked to complete the following questionnaires: Toronto Alexithymia scale, Snaith–Hamilton Pleasure Scale, and Short Form Health Survey. Biological markers of adherence to treatment were measured. Peritoneal dialysis patients showed a lower capacity to feel pleasure from sensorial experience (p = .011) and a higher values of phosphorus compared to the other patients’ groups (p = .0001). The inability to communicate emotions was negatively correlated with hemoglobin levels (r = −(0).69; p = .001) and positively correlated with phosphorus values in the PD patients (r = .45; p = .050). Findings showed higher psychological impairments and a lower adherence to the treatment in PD patients and suggest the implication of emotional competence in adherence to treatment.The aim of the study was to investigate the association between psychological characteristics and biological markers of adherence in chronic kidney disease patients receiving conservative therapy, hemodialysis, peritoneal dialysis (PD), or kidney transplantation. Seventy-nine adult patients were asked to complete the following questionnaires: Toronto Alexithymia scale, Snaith-Hamilton Pleasure Scale, and Short Form Health Survey. Biological markers of adherence to treatment were measured. Peritoneal dialysis patients showed a lower capacity to feel pleasure from sensorial experience (p = .011) and a higher values of phosphorus compared to the other patients' groups (p = .0001). The inability to communicate emotions was negatively correlated with hemoglobin levels (r = -(0).69; p = .001) and positively correlated with phosphorus values in the PD patients (r = .45; p = .050). Findings showed higher psychological impairments and a lower adherence to the treatment in PD patients and suggest the implication of emotional competence in adherence to treatment

    Atomically precise rhodium nanoclusters: synthesis and characterization of the heterometallic [Rh18Sn3Cl2(CO)33]4- and Rh7Sn4Cl10(CO)14]5- carbonyl compounds

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    This paper presents a deepening on the investigation of the Rh-Sn system of heterometallic carbonyl clusters. More specifically, we herein report the synthesis and isolation of the new [Rh7Sn4Cl10(CO)14]5− (1) compound and the atomically precise [Rh18Sn3Cl2(CO)33]4− (2) nanocluster. Cluster 1 can be obtained by reacting the [Rh7(CO)16]3− homometallic cluster with hydrated Sn(II) chloride, in acetone; conversely, cluster 2 derives from the previously known [Rh12Sn(CO)23Cl2]4− precursor after controlled addition of diluted sulphuric acid. Notably, only 2 has retained the recurrent Sn-centred icosahedral structural feature, while 1 shows a molecular structure based on two Rh4 tetrahedra joint by one vertex and stabilized by SnCl2 and [SnCl3]− fragments. Both species have been characterized by infrared (IR) analysis in solution, single-crystal X-ray diffraction and Electrospray Ionization Mass Spectrometry (ESI-MS)
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