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排序方式: 共有103条查询结果,搜索用时 15 毫秒
1.
In this work, a possible way for partial CO2 emissions reduction from gas turbine exhausts by co-firing with biomass is investigated. The basic principle is the recirculation of a fraction of the exhausts (still rich in oxygen) to a gasifier, in order to produce syngas to mix with natural gas fuel. As biomass is a CO2 neutral fuel, the fraction of replaced natural gas is a measure of CO2 removal potential of the powerplant. 相似文献
2.
This paper presents an operational analysis of the prototype of an innovative fully autonomous wind powered desalination system. The system consists of a wind farm, made up of two wind turbines and a flywheel, which operates in isolation from the conventional power grids and which supplies the energy needs of a group of eight reverse osmosis (RO) modules throughout the complete desalination process (from the pumping of sea water to the storage of the product water), as well as the energy requirements of the control subsystems. The analysis of the electrical and hydraulic results obtained from this prototype, installed on the island of Gran Canaria in the Canarian Archipelago, shows the technical feasibility of the system design and the automatic operational strategy programmed for it. Amongst other tasks, the automatic operational strategy controls the number of RO plants that have to be connected or disconnected at any given moment in order to match the variable wind energy supply. The results obtained thus far have not revealed any significant variation in the level of quality or average volume of the product water, nor any physical deterioration to the main components of the system as a result of the start-ups and shut-downs required as a result of the variations in the wind energy supply or oscillations of the electrical parameters of voltage and frequency. In conclusion, the system under analysis can be applied to sea water desalination, both on a small and large scale, in coastal regions with a scarcity of water for domestic and/or agricultural use but with wind energy resources. 相似文献
3.
Francesca Guidi Giovanni Carta Gilberto Rossetto Guido Salmaso 《Electrochimica acta》2005,50(23):4609-4614
Alumina (Al2O3) coatings of different thickness were deposited on OT59 brass substrate (BS) using the metal organic chemical vapour deposition (MOCVD) technique to evaluate the corrosion performance by EIS measurements. The used precursor was dimethyl-aluminium-isopropoxide. Electrochemical characterizations of the deposited films were performed in a standard very aggressive acidic solution (aerated 1N H2SO4 at 25 °C up to 168 h of immersion time) by means of direct current method (Tafel curves) and electrochemical impedance spectroscopy (EIS). The Rutherford backscattering spectroscopy (RBS) indicated that the films are very pure with the correct Al2O3 stoichiometry, while the IR absorption spectra showed that the films did not contain any OH groups. The surface film morphology was investigated by atomic force microscopy (AFM) and displayed a globular texture. The films were very smooth, with a maximum root mean square roughness, for example, of 14 nm for a 0.96 μm thick coating. The EIS data confirmed, as expected, that a 2.40 μm Al2O3 layer ensures the best corrosion protection after 168 h of immersion in the very acidic environment used. 相似文献
4.
Vladimir A. Tyurin Gianfranca Carta Yulia Y. Tyurina Sebastiano Banni Billy W. Day Francesco P. Corongiu Valerian E. Kagan 《Lipids》1997,32(2):131-142
Recent studies provide extensive evidence for the importance of carotenoids in protecting against oxidative stress associated
with a number of diseases. In particular, reactions of carotenoids with phenoxyl radicals generated by peroxidasecatalyzed
one-electron metabolism of phenolic compounds may represent an important antioxidant function of carotenoids. To further our
understanding of the antioxidant mechanisms of carotenoids, we used in the present work two different phenolic compounds,
phenol and a polar homologue of vitamin E (2,2,5,7,8-pentamethyl-6-hydroxychromane, PMC), as representatives of two different
types of phenols to study reactions of their respective phenoxyl radicals with carotenoids in cells and in model systems.
We found that phenoxyl radicals of PMC did not oxidize β-carotene in either HL-60 cells or in model systems with horseradish
peroxidase (HRP)/H2O2. In contrast, the phenoxyl radicals generated from phenol (by native myeloperoxidase in HL-60 cells or HRP/H2O2 in model systems) effectively oxidized β-carotene and other carotenoids (canthaxanthin, lutein, lycopene). One-electron reduction
of the phenoxyl radical by ascorbate (assayed by electron spin resonance-detectable formation of semidehydroascorbyl radicals)
prevented HRP/H2O2-induced oxidation of β-carotene. PMC, but not phenol, protected β-carotene against oxidation induced by a lipid-soluble azo-initiator
of peroxyl radicals. No adducts of peroxidase/phenol/H2O2-induced β-carotene oxidation intermediates with phenol were detected by high-performance liquid chromatography-mass spectrometry
analysis of the reaction mixture. Since carotenoids are essential constituents of the antioxidant defenses in cells and biological
fluids, their depletion through the reaction with phenoxyl radicals formed from endogenous, nutritional and environmental
phenolics, as well as phenolic drugs, may be an important factor in the development of oxidative stress. 相似文献
5.
Roberto Saia Ludovico Boratto Salvatore Carta 《Journal of Intelligent Information Systems》2016,47(1):111-134
Recommender systems usually suggest items by exploiting all the previous interactions of the users with a system (e.g., in order to decide the movies to recommend to a user, all the movies she previously purchased are considered). This canonical approach sometimes could lead to wrong results due to several factors, such as a change in user preferences over time, or the use of her account by third parties. This kind of incoherence in the user profiles defines a lower bound on the error the recommender systems may achieve when they generate suggestions for a user, an aspect known in literature as magic barrier. This paper proposes a novel dynamic coherence-based approach to define the user profile used in the recommendation process. The main aim is to identify and remove, from the previously evaluated items, those not semantically adherent to the others, in order to make a user profile as close as possible to the user’s real preferences, solving the aforementioned problems. Moreover, reshaping the user profile in such a way leads to great advantages in terms of computational complexity, since the number of items considered during the recommendation process is highly reduced. The performed experiments show the effectiveness of our approach to remove the incoherent items from a user profile, increasing the recommendation accuracy. 相似文献
6.
《国际城市规划》(UPI)于2009年出版了一辑专刊,介绍了意大利城市规划的相关情况和背景.意大利是一个具有2 000多年文化创造传统的国度,城市在意大利的发展历程中始终发挥着重要作用.作为一个事实上的城邦国家,意大利的城市发展深受根植于当地的市民文化.
1城市新景象
最近几年,从佛罗里达(Florida)和兰德利(Landry)的著作开始,人们对“创意”这一城市竞争要素的反思和实验交织在一起,引发了对其理论与实践的进一步反省,其目的是为了给创意城市提供更宽阔的空间,付诸实际行动,提高实施效果,改善生活品质. 相似文献
7.
Dr. Lilia Clima Bogdan Florin Craciun Dr. Andrea Angeli Andrea Petreni Alessandro Bonardi Dr. Alessio Nocentini Dr. Fabrizio Carta Prof. Paola Gratteri Prof. Mariana Pinteala Prof. Claudiu T. Supuran 《ChemMedChem》2020,15(21):2052-2057
We report novel molecules incorporating the nontoxic squalene scaffold and different carbonic anhydrase inhibitors (CAIs). Potent inhibitory action, in the low-nanomolar range, was detected against isoforms hCA II for sulfonamide derivatives, which proved to be selective against this isoform over the tumor-associate hCA IX and XII isoforms. On the other hand, coumarin derivatives showed weak potency but high selectivity against the tumor-associated isoform CA IX. These compounds are interesting candidates for preclinical evaluation in glaucoma or various tumors in which the two enzymes are involved. In addition, an in silico study of inhibitor-bound hCA II revealed extensive interactions with the hydrophobic pocket of the active site and provided molecular insights into the binding properties of these new inhibitors. 相似文献
8.
Vincenzo Di Marzo Mikko Griinari Gianfranca Carta Elisabetta Murru Alessia Ligresti Lina Cordeddu Elena Giordano Tiziana Bisogno Maria Collu Barbara Batetta Sabrina Uda Kjetil Berge Sebastiano Banni 《International Dairy Journal》2010,20(4):231-235
Evidence suggests that dietary long chain polyunsaturated fatty acids (LCPUFAs), and particularly those belonging to the n-3 family, may influence the brain fatty acid profile and, thereby, the biosynthesis of endocannabinoids in rodents. However, the doses used are usually quite high and not comparable with human intake. Recently, we have shown that relatively low doses of dietary n-3 LCPUFAs (4 weeks), in the form of either fish or krill oil, balanced for EPA and DHA content, and against a control diet with no EPA and DHA and similar contents of oleic, linoleic and α-linolenic acids, lower the concentrations of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), in the visceral adipose tissue, and of AEA in the liver and heart, of obese Zucker rats. This, in turn, is associated with lower levels of arachidonic acid in membrane phospholipids and with amelioration of some metabolic syndrome parameters. We investigated here whether in Zucker rats, under the same conditions, fish and krill oil are also able to influence LCPUFA and endocannabinoid profiles in brain. Only krill oil was able to increase significantly DHA levels in brain phospholipids, with no changes in arachidonic acid. DHA increase was associated with lower levels of 2-AG in the brain, whereas AEA and its congeners, N-palmitoylethanolamine and N-oleoylethanolamine, were unchanged. We conclude that, despite the strong impact of dietary n-3 fatty acid on endocannabinoid levels previously observed in peripheral tissues, in the brain only 2-AG is affected by dietary krill oil, suggesting that the beneficial effect of the latter on the metabolic syndrome is mostly exerted by modifying peripheral endocannabinoids. Nevertheless, possible effects of dietary krill oil in the brain through modification of 2-AG levels deserve further investigation. 相似文献
9.
We present an electrostrictive polymer bimorph controllable with low voltage through an integrated CMOS OFET control system. We have actuated the device by applying voltages up to 400 V to the control system, and can actuate the control with 60 V switching. The electrostrictor material was used both as the substrate for the transistors and as the dielectric layer for the control circuitry. This allows for a reduction in the number of layers in the structure, minimizing the clamping effect that would compromise the strain capabilities of the device. We have characterized the macroscopic displacement of the structure through a radius of curvature measurement, ranging from 11.4 mm to 7.5 mm depending on the supply voltage provided. The architecture proposed can be scaled to larger system with higher supply voltages. 相似文献
10.
A plug flow reactor (PFR) which permits the growth of bacteria in a microwave environment is described. The apparatus is used to analyse the effect of microwave radiation at the frequency of 2.45 GHz and at 37°C on the growth rate of three bacterial species: Bacillus clausii, Pseudomonas aeruginosa, and Staphylococcus aureus. The growth constant is determined for reacting mixtures irradiated with microwaves of different powers ranging from 0 to 400 mW. Analyses show that (a) the apparatus is able to perform the experimental runs maintaining an aseptic environment; (b) under the microwave power levels examined in the present study, no effects are detected for the Bacillus clausii and Pseudomonas aeruginosa species, while for the Staphylococcus aureus species, a few small effects are found (a minimum value of the growth constant at 200 mW and an increase of the constant between 200 and 400 mW). © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献