1,721,072 research outputs found
PERFORMANCE ASSESSMENT AND OPTIMIZATION OF MULTI-PURPOSE SOLAR THERMAL SYSTEMS
No full textEven under the powerful thrust of 20-20-20 measures, solar thermal systems are experiencing a slow-down in their development in most EU countries. One reason is the growing competition with photovoltaic (PV) systems; another one is their traditional confinement to sanitary hot water (SHW) production. In order to widen the use of solar thermal collectors (STC), they should also be able to contribute to space heating and cooling and become multi-purpose STC. This paper addresses the issue of optimal sizing of multi-purpose STC systems. The criterion adopted is based on maximization of Net Present Value and has been applied to some Italian cities and in Pakistan with diverse weather conditions. Results show that optimal thermal collector areas per peak cooling demand (Ac/Pc) can be conveniently expressed as a function of Peak Heating to Cooling Ratio (Ph/Pc). The optimum Ac/Pc varies between 3 and 5 m2/kWc and decreases with increasing Ph/Pc. The paper also analyses and compares a STC-based system with a multi-purpose PV-based heat pump system using a traditional one (boiler and compression chiller) as reference. Results show that steadily decreasing prices have made PV systems more favorable, even without consideration of public subsidies. Finally, the limit cost of STC in order to reach the same cost effectiveness of PV systems is calculate
DISMI - an intent interface for application-centric transport network services
No full textApplication-centric networking is a novel approach to construct transport networks that allows application-specific requirements to be taken into account through the entire service provisioning process: the service offered to each application is differentiated at each layer of the transport network, from IP to optical. This approach replaces the grooming of traffic with different requirements into a shared path in the transport layer, and allows for a finer control and utilization of network resources by network operators. To make this concept viable, an interface for requesting a connectivity service by applications requires an abstraction with respect to the various underlying network technologies. Interfaces based on the concept of Intents provide such an abstraction: applications can describe what they need from the network (their requirements) rather than how to achieve them. This paper describes the design and implementation of the solution we propose: DISMI, the Intent-based North-Bound Interface of a network controlle
Experimental and theoretical analysis of thermal solar collector systems for DHW in northern Italy
Get PDFSolar collectors performance evaluation has some established standards, represented by UNI 12976 and ISO 9806. Nevertheless, solar collectors are often installed as part of more complex Domestic Hot Water system (DHW). The aim of this work is to describe a methodology adopted for the experimental efficiency evaluation of Solar Collector systems for DHW production (SCDHW). In situ measurements of solar collector DHW system performance, including DHW storage and back-up heating system, have been compared with results from simulations performed using widely spread commercial software and f- chart method. In this paper ten SCDHW systems were analyzed. e. In situ measurements was carried out for at least 20 days for each plant, with sampling rate of ten minutes using ultra sound flow meter, and temperature probes. Almost all the plants had a previously installed heating power logger. Results show that generally the solar collector's area was exceeding actual DHW needing, resulting in measured lower efficiency (around 30%) than calculate by commercial software. Discrepancies between the measured and simulated data are probably due to unpredictable control system and end users behavior.Fil: Arboit, Mariela Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina. Università di Torino; ItaliaFil: Toniolo, J.. Università di Torino; ItaliaFil: Ghafoor, A.. Università di Torino; ItaliaFil: Fracastoro, G.V. Università di Torino; Itali
In-field monitoring and numerical parametric analysis of a small size adsorption solar cooling plant in Italy
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An interactive intent-based negotiation scheme for application-centric networks
No full textThe demonstration presents the first implementation of a resource negotiation scheme between users and a network for the provisioning of application-aware connectivity services. This active interaction enables the users, who request connectivity services with multiple application requirements, to select an alternative solution when the network does not have enough resources to satisfy the original requests
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Irrigation and soil management strategies for usingsaline-sodic water in a cotton–wheat rotation
No full textConsequent to population growth and high living standards in several and and semi-arid regions, competition for freshwater among different water-use sectors is expected to increase vis-a-vis its decreased allocation to irrigation. Non-conventional water resources, such as saline and/or sodic drainage and groundwater represent complementary supply to narrow the gap between freshwater availability and demand. We carried out a 3-year field study in the Indus Plains of Pakistan to evaluate different irrigation and soil management strategies for using saline-sodic water to grow cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) on a sandy loam soil (ECe = 1.3-1.76 dS m(-1), pH(s) = 8.47-8.61, SAR = 5.50-7.41, infiltration rate = 0.6-0.8 cm h(-1), p(b) = 1.56-1.61 Mg m(-3)). The treatments were: (1) irrigation with freshwater from a nearby canal (FW); (2) irrigation with saline-sodic water (EC = 3.32 dS m(-1), SAR = 16.29, SAR(adj) = 18.24, RSC = 5.25 mmol(c) L-1) (SSW); (3) cyclic use of fresh and saline-sodic water through alternate irrigations (FW - SSW); (4) Soil application of farm manure at 25 Mg ha(-1) year(-1) and irrigation with saline-sodic water (FM + SSW); and (5) soil application of gypsum equivalent to gypsum requirement of saline-sodic water and irrigation with the same water (G + SSW). The seed yield of first cotton crop was not significantly affected by different treatments. The yields of subsequent wheat and cotton crops were lower in the SSW than other treatments, indicating negative impacts of saline-sodic water when used in the absence of a soil or irrigation management approach. The treatments using saline-sodic water did increase soil ECe and SAR levels, but this increase was only significant in SSW treatment. Irrigation with saline-sodic water together with amendments significantly increased infiltration rate than SSW alone, where bulk density was increased. The net benefit was the maximum from FW - SSW treatment followed by FW, G + SSW, FM + SSW and SSW. (c) 2005 Elsevier B.V. All rights reserved
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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