1,720,995 research outputs found
Water losses dynamic modelling in water distribution networks
No full textIn the last decades, one of the main concerns of the water system managers have been the minimisation of water losses, that frequently reach values of 30% or even 70% of the volume supplying the water distribution network. The economic and social costs associated with water losses in modern water supply systems are rapidly rising to unacceptably high levels. Furthermore, the problem of the water losses assumes more and more importance mainly when periods of water scarcity occur or when not sufficient water supply takes part in areas with fast growth. In the present analysis, a dynamic model was used for estimating real and apparent losses of a real case study. A specific nodal demand model reflecting the user's tank installation and a specific apparent losses module were implemented. The results from the dynamic model were compared with the modelling estimation based on a steady-state approach
Energy, water and environmental balance of a complex water supply system
Full text linkThe present paper describes the analysis of water and energy balance in a complex
urban water supply system. The analysis was carried out employing Life Cycle
Analysis (LCA) methodologies. The LCA approach was integrated with the
analysis of the system energy and water balance. For a real size water supply
system, based on the results of the individual LCAs, the current baseline was
constructed highlighting the water, energy and environmental (in terms of CO2eq
emissions in the atmosphere) costs of supplied water. Then, three different
mitigation measures have been evaluated: the first is based on energy production
by installation of photovoltaic systems; the second is based on energy recovery by
means of hydraulic turbines, exploiting the available pressure potential to produce
energy; the third based on energy optimization of pumping stations by installing
inverter systems, replacement of rotors with optimized blade profiles and
installation of automation systems and self-control. Also the possibility of
substituting some of the pipes of the water supply system was considered in the
recovery scenario in order to reduce leakages and recovery the energy needed for
leakages transport and treatment. The analysis of the results shown that energy
recovery scenario is the most reliable solution even without any pipe substitution.
Thanks to the recovery of energy and limiting the environmental impact of the
system, the CO2eq production per cubic meter of supplied water was reduced from
0.41 to 0.07 kg CO2eq/m3 of supplied water
Multivariate Statistical Analysis for Water Demand Modeling
Full text linkAbstractThe actual level of water demand is the driving force behind the hydraulic dynamics in water distribution systems. Consequently, it is crucial to estimate it as accurately as possible in order to result in reliable simulation models. In this paper, a copula-based multivariate analysis has been proposed and used for demand prediction for given return period. The analysis is applied to water consumption data collected in the water distribution network of Palermo (Italy). The approach showed to produce consisted demand patterns and to be a powerful tool to be coupled with water distribution network models for design or analysis problems
Multi-stage linear programming optimization for pump scheduling
Full text link12th International Conference on Computing and Control for the Water Industry, CCWI2013This study presents a methodology based on Linear Programming for determining the optimal pump schedule on a 24-hour basis, considering as decision variables the continuous pump flow rates which are subsequently transformed into a discrete schedule. The methodology was applied on a case study derived from the benchmark Anytown network. To evaluate the LP reliability, a comparison was made with solutions generated by a Hybrid Discrete Dynamically Dimensioned Search (HD-DDS) algorithm. The cost associated with the result derived from the LP initial solution was shown to be lower than that obtained with repeated HD-DDS runs with differing random seeds
Multi Sources Water Supply System Optimal Control: A Case Study
No full textAbstractThe optimal operation of a multi quality network was analysed applying Linear Programming methods. The peculiar service condition of the industrial city of Gela (Italy) was investigated. The network is supplied both from waters derived from a desalination plant and other natural sources. The method aimed to minimise energy cost and find the optimal operation control, while satisfying demand and quality constraints, specifically with regard to water temperature. The method proved to be effective in the selection of the optimal management strategy after the definition of a specific water quality target
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Melanoma cells release extracellular vesicles which contain RNA-binding proteins able to bind the mRNA encoding histone H1°
No full textExtracellular vesicles (EVs) are produced by most prokaryotic and eukaryotic cells; tumour cells, however, release much higher amounts of EVs, which contain cancer-specific proteins and RNAs. Molecules carried by EVs are captured by surrounding cells, which then undergo profound phenotypic modifications. G26/24 oligodendroglioma cells release, for example, EVs containing FasL and TRAIL, which induce apoptosis in rat cortical neurons and astrocytes in culture. By metabolic labelling of cells, EV-mediated horizontal transfer of radioactive proteins was clearly demonstrated. Among the proteins present in EVs produced by oligodendroglioma cells, extracellular matrix remodelling proteases, and the linker histone H1°, a differentiation-specific histone, were identified. We also found that A375 melanoma cells release EVs which, like the once produced by oligodendroglioma cells, contain H1°. Interestingly, H1° histone sorted to vesicles has a molecular mass higher than expected, and is probably sumoylated.
More recently, by a T1 RNase-protection assay, done by mixing an in-vitro transcribed, H1°- encoding RNA, and EVs, three main RNA-protein complexes were evidenced, the most abundant of which had an apparent molecular mass of about 65 kDa. We then synthesized a biotinylated H1° RNA, with the aim to fish, by affinity chromatography, the evidenced proteins. The RNA-bound fraction was finally analysed by mass spectrometry. The most abundant protein identified was the myelin expression factor-2 (MYEF2), which has indeed a molecular mass of about 60 kDa. The presence of MYEF2 in EVs released from A375 melanoma cells was finally confirmed by Western blot analysis
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