4,184 research outputs found
Improving operation of a complex headworks system for municipal use and hydropower production by mathematical programming
The paper presents a Mixed Integer Non Linear Programming (MINLP) model of the water resources system supplying Genoa, in northern Italy. The system presently features five reservoirs, three main river intakes, and two well fields. The hydrological regime is typically Mediterranean; water availability is however relatively abundant, so that drought issues are limited, especially now that water demand from the supply sources has decreased due to reduced population, deindustrialization and to improvement in the operation and maintenance of the water distribution network. In this context, it is worthwhile considering the possibility to relax an over-conservative management of resources, justified by the experience of previous drought events, and to explore the viability of exploiting resources from reservoirs for hydropower production.
The MINLP model expresses cost minimization over a 40 year time period on a monthly basis, subject to physical constraints. Costs include scarcity costs (the economic value of possible water deficits) and extraction costs from wells, minus hydropower production. The model has been written in GAMS and solved through the SBB (Simple Branch and Bound) solver.
Results show that the system is able to meet demand over the 40 year hydrologic scenario with negligible water deficits and that hydropower production may be enhanced compared to present by increasing releases from reservoirs, which ultimately implies accepting keeping reservoirs emptier than presently done
Weakly Coupled Motion of Individual Layers in Ferromagnetic Resonance
We demonstrate a layer- and time-resolved measurement of ferromagnetic
resonance (FMR) in a Ni81Fe19 / Cu / Co93Zr7 trilayer structure. Time-resolved
x-ray magnetic circular dichroism has been developed in transmission, with
resonant field excitation at a FMR frequency of 2.3 GHz. Small-angle (to 0.2
degree), time-domain magnetization precession could be observed directly, and
resolved to individual layers through elemental contrast at Ni, Fe, and Co
edges. The phase sensitivity allowed direct measurement of relative phase lags
in the precession oscillations of individual elements and layers. A weak
ferromagnetic coupling, difficult to ascertain in conventional FMR
measurements, is revealed in the phase and amplitude response of individual
layers across resonance.Comment: 22 pages, 6 figures submitted to Physical Review
Using cardiorespiratory fitness assessment to identify pathophysiology in long COVID – Best practice approaches
Cardio-respiratory fitness (CRF) is well-established in the clinical domains as an integrative measure of the body's physiological capability and capacity to transport and utilise oxygen during controlled bouts of physical exertion. Long COVID is associated with >200 different symptoms and is estimated to affect ∼150 million people worldwide. The most widely reported impact is reduced quality of life and functional status due to highly sensitive and cyclical symptoms that manifest and are augmented following exposure to physical, emotional, orthostatic, and cognitive stimuli, more commonly known as post-exertional symptom exacerbation (PESE) which prevents millions from engaging in routine daily activities. The use of cardiopulmonary exercise testing (CPET) is commonplace in the assessment of integrated physiology; CPET will undoubtedly play an integral role in furthering the pathophysiology and mechanistic knowledge that will inform bespoke Long COVID treatment and management strategies. An inherent risk of previous attempts to utilise CPET protocols in patients with chronic disease is that these are compounded by PESE and have induced a worsening of symptoms for patients that can last for days or weeks. To do this effectively and to meet the global need, the complex multi-system pathophysiology of Long COVID must be considered to ensure the design and implementation of research that is both safe for participants and capable of advancing mechanistic understanding
Conceptual design of the enhanced coolant purification systems for the European HCLL and HCPB test blanket modules
The Coolant Purification Systems (CPSs) is one of the most relevant ancillary systems of European Helium Cooled Lead Lithium (HCLL) and Helium Cooled Pebble Bed (HCPB) Test Blanket Modules (TBMs) which are currently in the preliminary design phase in view of their installation and operation in ITER. The CPS implements mainly two functions: the extraction and concentration of the tritium permeated from the TBM modules into the primary cooling circuit and the chemistry control of helium primary coolant. During the HCLL and HCPB-TBSs (Test Blanket Systems) Conceptual Design Review (CDR) in 2015 it was recognized the need of reducing the tritium permeation into the Port Cell #16 of ITER. To achieve this and, then, to lower the tritium partial pressure in the Helium Cooling Systems in normal operation, the helium flow-rate treated by each CPS has been increased of almost one order of magnitude. In 2017, to satisfy the CDR outcomes and the new design requirements requested by Fusion for Energy (F4E, the European Domestic Agency for ITER), ENEA performed a preliminary design of the “enhanced” CPSs. This paper presents the current design of the “enhanced” CPSs, focusing on design requirements, assumptions, selection of technologies and preliminary components sizing
Output-only identification of rigid body motions of floating structures: a case study
In order to identify rigid body motions of floating offshore structures, output-only techniques are very useful for developing low-cost intermediate-scale experimental activities directly into the sea, instead of wave tanks. A crucial parameter, however, is the length of the response records used as input for the identification process, since short records may result in significant loss of accuracy, while long ones may be incompatible with the assumption of stationarity of the sea state. This work presents a sensitivity study conducted on a numerical model of a spar structure, identified by means of Enhanced Frequency Domain Decomposition method. An overview on the efficiency of the method is given for various lengths of response record, along with practical indications on the minimum values acceptable
Comparative Studies on Different Citrus Cultivars: A Revaluation of Waste Mandarin Components
Peel, pulp and seed extracts of three mandarin varieties, namely Phlegraean mandarin (Citrus reticulata), Kumquat (Citrus japonica), and Clementine (Citrus clementina) were compared and characterised in terms of photosynthetic pigment content, total polyphenols amount, antioxidant activity and vitamin C to assess the amount of functional compounds for each cultivar. The highest polyphenols content was found in the Phlegraean mandarin, especially in peel and seeds, whereas Kumquat exhibited the highest polyphenols amount in the pulp. The antioxidant activity was higher in the peel of Phlegraean mandarin and clementine compared to Kumquat, which showed the highest value in the pulp. The antioxidant activity peaked in the seeds of Phlegraean mandarin. The vitamin C in the Phlegraean mandarin was the highest in all parts of the fruit, especially in the seeds. Total chlorophyll content was comparable in the peel of different cultivars, in the pulp the highest amount was found in clementine, whereas kumquat seeds showed the greatest values. As regards total carotenoids, peel and pulp of clementine exhibited higher values than the other two cultivars, whereas the kumquat seeds were the richest in carotenoids. Among the analysed cultivars Phlegraean mandarin may be considered the most promising as a source of polyphenols and antioxidants, compared to the clementine and Kumquat, especially for the functional molecules found in the seeds. Moreover, regardless of cultivars this study also highlights important properties in the parts of the fruit generally considered wastes
The Use of a Plant-Based Biostimulant Improves Plant Performances and Fruit Quality in Tomato Plants Grown at Elevated Temperatures.
Abiotic stresses can cause a substantial decline in fruit quality due to negative impacts on plant growth, physiology and reproduction. The objective of this study was to verify if the use of a biostimulant based on plant and yeast extracts, rich in amino acids and that contains microelements (boron, zinc and manganese) can ensure good crop yield and quality in tomato plants grown at elevated temperatures (up to 42 C). We investigated physiological responses of four di↵erent tomato landraces that were cultivated under plastic tunnel and treated with the biostimulant CycoFlow. The application of the biostimulant stimulated growth (plants up to 48.5% taller) and number of fruits (up to 105.3%). In plants treated with the biostimulant, antioxidants contents were higher compared to non-treated plants, both in leaves and in fruits. In particular, the content of ascorbic acid increased after treatments with CycoFlow. For almost all the traits studied, the e↵ect of the biostimulant depended on the genotype it was applied on. Altogether, the use of the biostimulant on tomato plants led to better plant performances at elevated temperatures, that could be attributed also to a stronger antioxidant defence system, and to a better fruit nutritional quality
Facing metal stress by multiple strategies: morphophysiological responses of cardoon (Cynara cardunculus L.) grown in hydroponics
The contamination of environments by heavy metals has become an urgent issue causing undesirable accumulations and severe damages to agricultural crops, especially cadmium and lead which are among the most widespread and dangerous metal pollutants worldwide. The selection of proper species is a crucial step in many plant-based restoration approaches; therefore, the aim of the present work was to check for early morphophysiological responsive traits in three cultivars of Cynara cardunculus (Sardo, Siciliano, and Spagnolo), helping to select the best performing cultivar for phytoremediation. For all three tested cultivars, our results indicate that cardoon displays some morphophysiological traits to face Cd and Pb pollution, particularly at the root morphology level, element uptake ability, and photosynthetic pigment content. Other traits show instead a cultivar-specific behavior; in fact, stomata plasticity, photosynthetic pattern, and antioxidant power provide different responses, but only Spagnolo cv. achieves a successful strategy attaining a real resilience to metal stress. The capacity of Spagnolo plants to modify leaf structural and physiological traits under heavy metal contamination to maintain high photosynthetic efficiency should be considered an elective trait for its use in contaminated environments
Combination of freezing, low sodium brine, and cold smoking on the quality and shelf-life of sea bass (Dicentrarchus labrax l.) fillets as a strategy to innovate the market of aquaculture products
Aquaculture is playing a leading role in both meeting the growing demand for seafood and increasing the sustainability of the fish production sector. Thus, innovative technologies that improve its sustainability, competitiveness, and safety are necessary for growth in the sector. This study aimed to develop cold smoked sea bass fillets from aquaculture. The aptitude of frozen and fresh fillets for cold smoking was investigated by processing both fresh and thawed fillets kept previously at −20◦C for 15, 30, 60, and 90 days. Moreover, to develop a low-salt product, fillets were immersed in low-sodium or standard brine. Sensory, biochemical, and physical-chemical analyses were performed on both the raw fillets and the smoked fillets during vacuum packaged storage for 35 days at 1 ± 0.5◦C. Young modulus values, representative of texture and sensory evaluation, showed that the quality of fresh fillets was better compared to the thawed ones, thus affecting the quality of the final product as the correlation between parameters showed (principal component analysis). Cold smoking was effective in both maintaining the total volatile basic nitrogen (TVB-N) below the threshold for spoilage and preventing lipid peroxidation. Moreover, partial sodium replacement by potassium did not alter the sensory attributes of smoked fillets, which maintained high scores up to 21 days
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