222 research outputs found

    CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2capture: Techno-economic analysis

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    Among the carbon capture and storage (CCS) technologies suitable for power generation plants, partial oxy-combustion coupled with post combustion CO2capture is gaining interest, since such a hybrid configuration could allow to reduce the size and enhance the performance of post-combustion CO2capture by operating combustion with air enriched with oxygen and reducing the dilution of flue gas. Moreover, partial oxy-combustion is a potential candidate for the retrofit of existing steam plants because it could be based on an almost conventional boiler and requires a smaller CO2capture section. This work presents the results of a comparative techno-economic analysis of a 1000 MWthpartial oxy-combustion plant based on an ultra-supercritical pulverized coal combustion power plant integrated with a post-combustion CO2capture system and geological storage in saline aquifer. In particular, plant performance is assessed by using simulation models implemented through Aspen Plus 7.3 and Gate Cycle 5.40 commercial tools, whereas economic performance are evaluated on the basis of the expected annual cash flow. The analysis shows that, for new plants, this hybrid approach is not feasible from the economic point of view and full oxy-combustion potentially remains the most profitable technology even if, in the short-term period, the lack of commercial experience will continue to involve a high financial risk

    Implementation of a Simulating Code for Heating and Cooling Networks for Residential, Commercial and Tertiary Buildings☆

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    Abstract In the present energy scenario in which efficiency and sustainability will take the primary role in the decision making process it becomes more and more important to dispose of reliable simulating codes which allow to highlight the pros and cons of a given energy installation. New and old (forgotten) technologies are nowadays challenging the traditional technologies in different sectors of energy transformation from power generation down to heating and air conditioning. In the present situation of fuel cost oscillations and with the perspective of long-term scarcity of fuels, new, less energy demanding systems must be employed to maintain the actual comfort level. The present work aims at creating a reliable tool for correct evaluation of energy performance of heating and cooling networks. A code has been implemented in Simulink environment to simulate the network behaviour in summer and winter weather condition and to evaluate the primary energy indexes for comparison with the traditional configuration of a distributed heating and cooling plants common in residential, commercial and tertiary sectors. The code has been validated and the results will show the energy, economic and environment feasibility and convenience of one solution with respect to another for different climatic regions in Italy

    Preparazione di un nuovo reattivo supportato su fase solida per la realizzazione di reazioni radicaliche

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    Abbiamo preparato un derivato del 4-aril, N-idrossitiazol-2-(3H)-tione e lo abbiamo legato ad una glicina supportata su di una resina di tipo Wang. Su tale resina modificata sono stati supportati successivamente alcoli ed acidi carbossilici. I prodotti così ottenuti sono stati sottoposti a fotolisi con una normale lampada con filamento di tungsteno da 200 W per generare dei radicali che sono stati intercettati da CBrCl3 con formazione dei corrispondenti bromuri alchilici

    Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation

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    Cartilaginous fish are commonly recognized as key species in marine ecosystems for their fundamental ecological role as top predators. Nevertheless, effective management plans for cartilagi- nous fish are still missing, due to the lack of knowledge on their abundance, distribution or even life-history. In this regard, this paper aims at providing new information on the life-history traits, such as age, maturity, reproductive period, in addition to diet characteristics of eleven rare cartilagi- nous fish inhabiting the Central-Western Mediterranean Sea belonging to the orders Chimaeriformes (Chimaera monstrosa), Hexanchiformes (Heptranchias perlo and Hexanchus griseus), Myliobatiformes (Aetomylaeus bovinus and Myliobatis aquila), Rajiformes (Dipturus nidarosiensis and Leucoraja circu- laris), Squaliformes (Centrophorus uyato, Dalatias licha and Oxynotus centrina) and Torpediniformes (Tetronarce nobiliana), useful for their assessment and for future management actions. Particularly, the present paper provides for the first time the age estimation of D. nidarosienis and L. circularis which were both found capable of becoming older than ten years. In addition, the present study updates the sizes of first maturity of C. uyato and D. licha, which appeared to be capable of reproducing earlier than what was previously hypothesized, representing very valuable information for a better understanding of these rare species populations status and, eventually, their conservation. On the basis of the stomach content analysis, it was possible to identify five different predator groups

    Optimizing the Mechanoluminescent Properties of CaZnOS:Tb via Microwave-Assisted Synthesis: A Comparative Study with Conventional Thermal Methods

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    Recent developments in lighting and display technologies have led to an increased focus on materials and phosphors with high efficiency, chemical stability, and eco-friendliness. Mechanoluminescence (ML) is a promising technology for new lighting devices, specifically in pressure sensors and displays. CaZnOS has been identified as an efficient ML material, with potential applications as a stress sensor. This study focuses on optimizing the mechanoluminescent properties of CaZnOS:Tb through microwave-assisted synthesis. We successfully synthesized CaZnOS doped with Tb3+ using this method and compared it with samples obtained through conventional solid-state methods. We analyzed the material's characteristics using various techniques to investigate their structural, morphological, and optical properties. We then studied the material's mechanoluminescent properties through single impacts with varying energies. Our results show that materials synthesized through microwave methods exhibit similar optical and, primarily, mechanoluminescent properties, making them suitable for use in photonics applications. The comparison of the microwave and conventional solid-state synthesis methods highlights the potential of microwave-assisted methods to optimize the properties of mechanoluminescent materials for practical applications

    On the presence of the Endangered white skate Rostroraja alba in Sardinian waters

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    The white skate Rostroraja alba is assessed by the International Union for Conservation of Nature as Endangered globally and is now considered rare in the Mediterranean. This species has never been recorded in Sardinian seas (central western Mediterranean), but an empty eggcase was collected on a sandy bottom off the western Sardinia coasts during the MEDiterranean International Trawl Survey (MEDITS) program in 2019. A morphometric and morphological description of the Sardinian eggcase, after a comparison with measurements from other Mediterranean and Atlantic specimens, showed it to be clearly ascribable to Rostroraja alba

    Glycated hemoglobin for the diagnosis of diabetes and prediabetes: Diagnostic impact on obese and lean subjects, and phenotypic characterization

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    Aims/Introduction Measurement of glycated hemoglobin (HbA1c) has been recommended for the diagnosis of diabetes and prediabetes. However, epidemiological studies have shown significant discordance between HbA1c and glucose-based tests. Of the factors that could influence agreement between HbA1c and the oral glucose tolerance test (OGTT), bodyweight has not been fully evaluated. The aims of the present study were to evaluate the impact of HbA1c criteria to diagnose diabetes and prediabetes compared with OGTT, and to examine HbA1c in relation to body mass index. Materials and Methods Two cohorts were studied, one from an obesity clinic (n = 592) and one from subjects undergoing screening for diabetes (n = 462). All underwent OGTT and HbA1c measurement. Results In the obese cohort, HbA1c ≥6.5% (≥48 mmol/mol) showed a sensitivity of 69.3% for diabetes, whereas HbA1c 5.7–6.4% (39–46 mmol/mol) did not identify prediabetes well (sensitivity 39.1%). In the diabetes screening cohort, HbA1c h

    Failure of Acute Ethanol Administration to Alter Cerebrocortical and Hippocampal Allopregnanolone Levels in C57BL/6J and DBA/2J Mice

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    Ethanol (EtOH) administration increases brain allopregnanolone levels in rats, and this increase contributes to sensitivity to EtOH's behavioral effects. However, EtOH's effects on allopregnanolone may differ across species. We investigated the effects of acute EtOH administration on allopregnanolone, progesterone, and corticosterone levels in cerebral cortex and hippocampus of C57BL/6J and DBA/2J mice, 2 inbred strains with different alcohol sensitivity

    The effect of by-pass linseed oil supplementation on the maternal antioxidant system during the embryo-maternal recognition period in ewes

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    This study analyzed the effects of dietary supplementation with by-pass linseed oil (LO; rich in α-linolenic acid) on maternal antioxidant systems at Days 14 and 16 of pregnancy in Sarda ewes. This trial used sixteen dry ewes. Eight ewes (CT group) were fed with a control diet without LO, and eight ewes (LO group) were fed with a diet supplemented with LO (10.8 g of α-linolenic acid/ewe/day). Both diets had similar crude protein and energy levels. The experiment included 10 days of an adaptation period and 31 days of a supplementation period. This supplementation period was divided into Period −2 (from Day −15 to −8), Period −1 (from Day −7 to −1; before synchronized mating period/Day 0), Period +1 (from Day +1 to + 7 after mating), and Period +2 (from Day +8 to +15 after mating). Estrous synchronization was induced in all the ewes using an intravaginal sponge (45 mg fluorgestone acetate) for 14 days and equine chorionic gonadotropin (350 UI/ewe) at the end of the treatment. On Days 14 (CT, N = 4; LO, N = 4) and 16 (CT, N = 4; LO, N = 4) after mating, the ewes were slaughtered. Samples of plasma, uterine, and luteal tissues were collected. Thiols, total antioxidant activity (TEAC), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content were measured. On Day 16, thiol and TEAC in luteal tissues were higher in the LO group when compared with the control one (p < 0.05). Moreover, TEAC was higher for the LO group in uterine tissues on Days 14 and 16 (p < 0.05). SOD activity was higher in the LO group in luteal and uterine tissues on Day 14 and Day 16, respectively (p < 0.001). On Day 16, uterine MDA content was lower for the LO group (p < 0.001). No differences were found between groups at the plasmatic level. However, the by-pass LO supplementation enhanced the analyzed antioxidant parameters in luteal and uterine tissues. In conclusion, these results demonstrate that by-pass LO supplementation exerted a positive effect on antioxidative defenses on maternal structures during the embryo-maternal recognition period in ewes. Thus, this could contribute to improving the maternal environment during the embryo-maternal recognition period in mammals
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